Association of Nociplastic Pain Features with Function in Aging Veterans with Chronic Low Back Pain

Association of Nociplastic Pain Features with Function in Aging Veterans with Chronic Low Back Pain | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Association of Nociplastic Pain Features with Function in Aging Veterans with Chronic Low Back Pain Victoria D Powell, Jinkyung Ha, Andrzej Galecki, Dan Clauw, Pooja Lagisetty, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8376244/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Chronic low back pain (CLBP) affects nearly one million Veterans and is a leading cause of disability. Nociplastic pain, characterized by altered central nervous system processing, widespread pain and sleep disturbance, may negatively impact treatment response in this population, yet remains underrecognized. Objective Determine the prevalence and association of nociplastic features with function among aging Veterans with CLBP. Design: Cross-sectional survey of Veterans aged 50–89 years with CLBP identified through VA administrative data. A stratified random sampling design oversampled women and Black/African-American veterans. Participants: Of 800 invited, 361 responded (45.1% response rate); after excluding those without CLBP, 342 participants were included (mean age 69.2 years, 19.2% women, 17.8% Black/African-American). Main Measures: Nociplastic features were assessed using the Fibromyalgia Survey Questionnaire to calculate a fibromyalgia severity score. Function was assessed via the Veterans RAND 12-Item Health Survey (VR-12) Physical (PCS) and Mental Component Summary (MCS) scores. Regression models adjusted for sociodemographics, comorbidities, opioid use, pain intensity, and surgical history. Key Results: Nociplastic characteristics were highly prevalent (fibromyalgia severity score mean 11.3, SD 5.9). Overall, 36% screened positive for fibromyalgia via American College of Rheumatology criteria, however, over half of respondents aged 50–64 years met criteria. Widespread pain was common; on average, pain was experienced in six discrete locations. Physical function was severely impaired (mean VR-12 PCS 30.2, nearly 2 SD below population norms); psychological function was moderately impaired (mean MCS 45). Higher fibromyalgia severity scores independently associated with poorer physical function (β= -0.30 per point increase, 95% CI -0.49, -0.12; p = 0.0014) and psychological function (β= -0.64, 95% CI -0.93, -0.35; p < 0.001) after adjustment. Gender, BMI, comorbidities, and back surgery were also associated with poorer function. Conclusions Nociplastic features are highly prevalent in aging Veterans with CLBP and demonstrate a dose-response relationship with impaired functioning. Recognition may guide more effective, mechanism-based treatment approaches and reduce harm. Geriatrics & Gerontology Anesthesiology & Pain Medicine Veterans aging chronic low back pain nociplastic pain Figures Figure 1 Introduction Chronic low back pain (CLBP) affects nearly one million US Veterans and is a common cause of functional impairment 1 , 2 . Aging Veterans, especially those above 50 years old, are considerably more affected than the general population 1 . Only about a quarter of older adults experience substantial improvement in back pain-related disability after a year of treatment 3 . One possible explanation for failure of certain treatments may be the unrecognized presence of nociplastic features of pain. “Nociplastic” is a recently described construct intended to specify the increasingly better understood mechanism whereby altered central nervous system processing causes a shift from pain as a straightforward perception of tissue or nerve injury (nociceptive or neuropathic pain mechanisms, respectively) to a complex emotional and threatening experience 4 , 5 . Nociplastic mechanisms likely underlie several chronic overlapping pain conditions (COPCs), or disorders of primary pain 6 . COPCs include conditions that frequently co-occur within individual patients, such as nonspecific CLBP, irritable bowel syndrome, fibromyalgia, and interstitial cystitis/bladder pain syndrome 6 . In COPCs, nociceptive input (such as inflammation and arthritis) may also be present but is insufficient to explain an individual’s pain intensity and interference. Accumulating evidence suggests a dose-response relationship between reporting more nociplastic features with poorer pain treatment outcomes. After undergoing surgeries intended to relieve pain, more severe nociplastic pain characteristics predict more post-operative pain and opioid use but less clinical improvement 7 – 9 . In contrast to nociceptive pain mechanisms, both targeting peripheral pain generators (for example, epidural steroid injections) and opioid therapy in patients who endorse many nociplastic pain symptoms results in poorer analgesia 10 – 12 . Rather, individuals with prominent nociplastic features may benefit more from education, psychotherapy, structured physical activity, and certain centrally-acting medications such as duloxetine 5 . Unfortunately, nociplastic features in aging patients may be especially underrecognized. One longitudinal study found recognition delayed for a mean of seven years 13 . During this time, patients received potentially ineffective peripherally-directed treatments yet did not receive other treatments more supported by evidence. The failure to recognize and appropriately treat nociplastic features and COPCs in aging patients may predispose them to progressive functional decline, disability, and frailty. However, it is unclear to what extent aging Veterans with CLBP, a highly prevalent COPC, report nociplastic features and whether nociplastic characteristics contribute to poorer physical and psychological function. We conducted a national survey of Veterans 50–89 years old with CLBP to test the hypothesis that more nociplastic features will be associated with worse physical and psychological functioning in a dose-dependent manner, even after adjustment for factors known to be associated with more severe functional impairment from pain (e.g. prior back surgeries, comorbidities, and pain intensity). We also hypothesized that nociplastic features will be more prevalent in later middle-age (50–64 years) vs older (65 + years) patients. Methods Study Population and Sample Selection Using the Veterans Affairs Corporate Data Warehouse and the Medicare Vital Status File, we identified 450,896 living Veterans 50–89 years old with at least two VA provider outpatient encounters from October 2018 to September 2022 where an ICD-10 code for low back pain (M54.5, M54.40, 41, 42, M54.89) 14 was assigned. Of those meeting selection criteria, 9.8% were women and 22% were Black/African-American (AA). The proportion of Veterans reporting Black/AA ancestry is 15.4%, and 7.4% of Veterans 50 years and older are women 27 . A stratified random sampling approach oversampled women and Black/AA Veterans by a factor of 2, identifying 800 individuals to receive study invitations. Appendix 1 contains the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) study flow diagram. Data Source Study data was obtained via completion of a one-time survey. Participants could choose to complete it either electronically (via Qualtrics FedRAMP instance) or via paper, but were instructed to only complete the survey once. The packet included an invitational letter with opt-out instructions, a QR code linking to Qualtrics; a study information sheet; the paper survey with a prepaid return envelope; and a $ 10 gift card. Neither the paper survey nor the electronic version was individually linked. A reminder packet was sent four weeks later to all not opting out. The study protocol was approved by the VA Ann Arbor Healthcare System Institutional Review Board. Measures Back PainChronicity All information was obtained by self-report. Participants endorsing current, ongoing back pain for ≥ 3 months were considered to have CLBP. Nociplastic Characteristics Features consistent with a nociplastic pain mechanism were assessed using the Fibromyalgia Survey Questionnaire (FSQ), an adaptation of the American College of Rheumatology (ACR) fibromyalgia survey criteria for survey research 18 . The FSQ assesses pain widespreadedness (Widespread Pain Index [WPI]) by asking participants to specify discrete body pain location(s). The Symptom Severity score (SSS) assesses additional co-occurring symptoms such as fatigue and trouble thinking or remembering. The total Fibromyalgia Severity (FS) score is the sum of the WPI and SSS, ranging from 0 (symptoms absent) to 31 (most severe) 19 . Respondents were considered to screen positive for fibromyalgia if they met 2016 ACR diagnostic criteria of WPI ≥ 7 and SSS ≥ 5 or WPI 4–6 and SSS ≥ 9 19 . We used this instrument both to ascertain those with severe nociplastic features (defined as meeting ACR fibromyalgia screening criteria) and as a continuous measure allowing capture of those with clinically important nociplastic features not necessarily meeting a cutpoint (i.e., subthreshold symptoms). This methodology has been used in multiple studies of chronic pain populations not otherwise diagnosed with fibromyalgia, including CLBP, finding dose-dependent relationships with higher FSQ scores predictive of more disability, more opioid use (but poorer response to opioids), and poorer response to procedures intended to relieve pain, such as surgery or steroid injections 7 – 9 , 20 , 21 . Function The Veterans RAND 12-Item Health Survey (VR-12) is a general measure of overall function and well-being extensively used in Veteran research and clinical applications 17 . The VR-12 Physical (PCS) and Mental Component Summary (MCS) scores assess physical and psychological function, respectively. Scores are standardized and normed to Veteran populations, with lower indicating poorer self-perception of overall function and well-being. Additional Measures Sociodemographic data obtained included age, gender, ethnicity, race, education level, employment status, tobacco use, weight, and height (to calculate body mass index [BMI]). Items adapted from the Health and Retirement Study 15 assessed the presence of comorbid conditions. An adapted questionnaire 16 was used to assess surgical and opioid use history. Patient Reported Outcomes Measurement and Information System (PROMIS) short forms assessed pain intensity and interference. The PainDETECT questionnaire was used to ascertain likelihood of neuropathic mechanisms contributing to back pain 22 . Data Handling and Analysis Paper survey data was double-coded and entered by two individuals then combined with Qualtrics data. Respondents without current CLBP were excluded from further analyses. Ambiguous paper survey responses (e.g. selection of multiple adjacent responses) were assigned one response via a random probability generator. For example, if a participant circled both “4” and “5” on a Likert scale, a random probability was generated; if ≥ 0.5, the response was coded as the higher value. Mutually exclusive responses (e.g. both “yes” and “no”) were coded as missing. The HealthMeasures Scoring Service 23 was used to generate standardized T-scores for PROMIS items. VR-12 data was scored using tool developers’ recommended code which produces a single imputation as long as a single item is non-missing 17 . Missing values in other variables were treated as missing at random. Missingness ranged from < 1% to 31%. Most items contained < 10% missing (Appendix 2). Descriptive analyses were performed on sample data. The PROC MI procedure in SAS version 9.4 (SAS Institute, Inc., Cary, NC) was used to generate and analyze 10 datasets with no missing values, imputed using fully conditional specification (FCS) 24 – 26 . All inferential analyses were performed on the imputed dataset. To characterize the association of nociplastic features with functioning, we constructed multiple linear regression models adjusting for age, gender, race, ethnicity, employment, education, history of back surgery, BMI, number of comorbidities, pain intensity, and prescription opioid use. R 2 values were used to assess goodness-of-fit 26 . The MI estimate of each statistic of interest in the regression models was calculated by averaging across the 10 imputed datasets according to Rubin’s rules 26 . Results In total, 361 surveys were returned or completed electronically (45.1% response rate). After excluding those without CLBP (n=19), the final sample contained 342 veterans who reported experiencing back pain for nearly 27 years on average. Most (86.5%) indicated back pain was a problem at least half the days in the past 6 months. The proportion of women (19.2%) and Black/AA (17.8%) respondents indicated adequate representation. Prescribed opioids were used by 14.0% for back pain specifically. Nearly one-third reported at least some prescribed opioid use in the last year, and approximately 15% used prescribed opioids long-term (≥3 months). Comorbidities were common, with hypertension and arthritis most frequently reported. Table 1 details respondent characteristics. Nociplastic Features: Participants experienced pain in a mean of 6 (SD 3.8) discrete locations, though there was marked variability (range 0-18, median 5, IQR 3-8). The fibromyalgia severity score mean was 11.3 (SD 5.9) with a similarly wide distribution (range 0-28, median 11, IQR 7-15). When grouped by age, respondents aged 50-64 years had fibromyalgia severity scores that were 3.3 points higher on average than those 65 years and older. Overall, 36% reported nociplastic features severe enough to meet 2016 ACR fibromyalgia diagnostic criteria. However, 51% of the younger group met criteria compared to just 29% of the older respondents. Function : On average, self-assessment of physical function was very poor, two SD below population norms (PCS T-score mean 30.2, SD 9.9). Respondents’ psychological status fared better; the MCS T-score mean of 45 (SD 13.4) was closer to the population average. Additional Pain Characteristics: Average pain intensity was 5.7/10 (SD 2.3) but ranged from 0 (no pain) –10 (worst pain imaginable). Both pain intensity and interference were severe in many cases, with mean T-scores greater than a standard deviation above population average. Slightly fewer than half reported back pain with likely or possible neuropathic features. Relationship of Nociplastic Features with Function: Details of regression analyses are presented in Table 2. Ten imputations produced n=3,350 complete cases available for analysis. Higher fibromyalgia severity scores (indicating more severe nociplastic features) were associated with lower significantly poorer physical function (β -0.03 (95% CI -0.49, -0.12), p=0.0014) and psychological function (β -0.64 (95% CI -0.93, -0.35), p<0.001), after adjusting for sociodemographic factors, pain intensity, surgical history, and opioid use.Altogether, more nociplastic features, higher pain intensity, higher BMI, more comorbidities, woman gender, and history of back surgery were significantly associated with poorer physical function (lower VR-12 PCS T-scores). Nociplastic features, higher pain intensity, and employment status other than employed full/part-time were significantly associated with poorer psychological function (lower VR-12 MCS T-scores). When grouped by younger age (50-64 years) vs older (≥65 years), younger respondents had significantly higher mean fibromyalgia severity scores (mean 13.6 (SD 5.9) vs 10.8 (SD 5.3), t (1795.1) = 13.18, p <.001). However, the directionality and slope of the relationship were not significantly different in the adjusted model; higher fibromyalgia severity scores were associated with poorer overall function regardless of age (Figure 1). A sensitivity analysis of complete cases from the sample produced similar results (Appendix 3). Discussion In this national sample of Veterans 50 years and older with CLBP, reporting features consistent with a nociplastic mechanism of pain (e.g., widespread pain and concurrent mood and sleep disturbance) robustly associated with poorer overall function. This dose-response relationship remained significant after controlling for sociodemographic and clinical factors known to associate with poorer functioning, such as older age. More than a third reported nociplastic features severe enough to meet diagnostic criteria for fibromyalgia, the prototypical nociplastic pain disorder, though the proportion was considerably higher among younger respondents. Despite sample selection based only on a single site of pain, participants reported experiencing six distinct painful sites on average, suggesting that multiple chronic pain conditions may be present in aging Veterans with CLBP. Notably, a minority of participants reported no or very few nociplastic characteristics, including localized back pain. Chronic nonspecific low back pain is one of multiple COPCs where nociplastic pain is considered the predominant pain mechanism. In these conditions, other pain mechanisms may be present, but they do not fully capture the pain experience either in severity or functional interference 28 . COPCs, including fibromyalgia, CLBP, and irritable bowel syndrome among others, are termed such because they commonly co-occur within individuals. The widespread pain in this national sample suggests the presence of additional COPCs in late middle-aged and older Veterans with CLBP. In this sample, nociplastic features were common, and in a significant minority, they were very severe. Similar to prior studies 7 – 9 , we benchmarked “severe” nociplastic features as those meeting 2016 ACR fibromyalgia screening criteria. The chronic, multisite pain experienced by patients with fibromyalgia, a condition defined by pain co-occurring alongside symptoms of fatigue, dyscognition, and unrefreshing sleep, is a prototypical example of the “nociplastic” pain category, a term coined to distinguish it from nociceptive and neuropathic pain 4 , 5 . When survey instruments are used to screen for fibromyalgia, prevalence ranges from 2–4% (general or non-clinical populations) to above 40% (patients presenting to a tertiary back pain clinic). 29 – 31 Similar to our findings, younger age, unemployment, higher pain severity, and poorer physical function were all associated with screening positive. Prior investigation into nociplastic characteristics among older veterans with CLBP has been extremely limited. One small study of Veterans > 65 years old noted a prevalence of approximately 25% 30 . Our finding a prevalence of about 35% may relate to our sample’s relatively younger mean age; indeed, when divided into younger (50–64 years) and older (≥ 65 years) respondents, prevalence was significantly higher in the younger group. Overall, patients with CLBP may have more prevalent and severe nociplastic features than in certain other chronic pain states. For example, only 8–9% of patients presenting for surgeries intended to relieve pain screen positive for fibromyalgia, indicating severe nociplastic features may be less prevalent 7 – 9 . Our findings support that persistent, nonspecific back pain is a disorder of primary pain rather than a result of peripheral pathology, such as degenerative changes seen on imaging. Clinically, nociplastic characteristics are important to recognize because their presence predicts poorer response to certain common treatments, especially those aimed at addressing peripheral pain generators as would be appropriate for nociceptive pain. For example, in patients undergoing surgery to relieve a painful condition (e.g. knee replacement, hysterectomy), reporting more nociplastic features predicts more post-operative pain, more opioid use, and less overall improvement 7 , 9 , 32 . In clinical trials of medial branch blocks and steroid injections, treatments aimed at addressing peripheral targets, participants with symptoms consistent with a nociplastic pain mechanism experience poorer outcomes 10 – 12 , 33 – 35 . Encouragingly, patients with prominent nociplastic features can benefit from targeted treatment. Grounded in a trusted clinician-patient relationship, multimodal approaches featuring both pharmacologic and behavioral treatments may be helpful 36 . In older adults, recognizing nociplastic features when seeking treatment for pain may be especially important to prevent or mitigate functional decline and frailty. Our findings suggest that older Veterans, especially those ≥ 65 years, have somewhat less severe nociplastic features on average than those in the 50–64 year age range. However, when nociplastic features are present, the association with poor function is no less prominent. Unfortunately, nociplastic features are likely underrecognized in older adults; one study 13 found that participants ≥ 55 years old reported symptoms an average of seven years before eventually receiving an appropriate fibromyalgia diagnosis. During that time, they received non-targeted treatments that were ineffective and potentially harmful. Though effective treatments for patients with prominent nociplastic features exist, precise recognition of pain mechanism(s) in any individual patient remains a matter of some debate. Recently, a stepped algorithmic approach to identifying nociplastic pain was recommended 4 , necessitating that pain must be chronic, widespread, and accompanied by central symptoms. Moreover, this approach requires the presence of sensory hypersensitivity, either assessed through a clinical history or evoked hypersensitivity testing. The instrument used in this study to assess nociplastic features does not explicitly ascertain hypersensitivity. However, the FSQ has been used as a continuous measure in multiple studies finding similarly that higher scores (indicating higher likelihood and severity of nociplastic pain) are associated with poorer functional outcomes 37 . The FSQ has several advantages, including brevity; it can be administered during routine clinical encounters and provide actionable information for clinical decision-making. This study has several limitations. As a cross-sectional survey, no causal conclusions can be made regarding the association with nociplastic features and poorer function. The survey response rate (45.1%), while higher than other mailout surveys of Veterans with CLBP 16 , is less than recent surveys using mixed-mode mail and phone follow up methods 38 . There is the possibility of recall bias and unmeasured confounding. As survey responses were anonymous, it is not possible to know whether respondents completed the survey multiple times. However, we believe that this occurring frequently enough to skew results is unlikely. Conclusions Our findings support that in aging Veterans with chronic low back pain, characteristics of nociplastic pain are common. Among those aged 50–64 years, nociplastic features may be more prevalent and severe than later in life. When examined along a continuum, there was a strong association with reporting more pronounced nociplastic attributes and poorer self-perception of overall physical and psychological function and well-being. Future investigations, including clinical trials of new pain interventions, should examine nociplastic features to determine the efficacy of novel treatments in this important but understudied group. Declarations Acknowledgements Contributors : We gratefully acknowledge the following research staff for assistance with data collection and entry: Marian Gelani, Jennifer Caldararo, and Elizabeth Firsht. Funders : Dr. Powell, Dr. Ha, Dr. Silveira, and Dr. Galecki received support from the National Institute on Aging (5P30AG024824-20, 5T32AG062403; 3T32AG062403-03S1). Dr. Ha and Dr. Powell received support from the Department of Veterans Affairs (VA) through a Pain Opioid CORE Rapid Start grant. Dr. Powell is supported by a VA Career Development Award (1IK2CX002646-01A2). Dr. Krein is supported by a VA research career scientist award (RCS 11-222). Prior presentations: Portions of this work have been presented at the Gerontological Society of America 2025 annual meeting, University of Michigan Pepper Center Research Education Core conference (2023), University of Michigan Palliative Care Research Seminar (2023), and the Pain Opioid CORE Career Development Workgroup (2023). Conflicts of Interest : Dr. Clauw reports grants and personal fees from Tonix and personal fees from Axsome and Merck. References Nahin RL. Severe Pain in Veterans: The Impact of Age and Sex, and Comparisons to the General Population. J Pain . 2017;18(3):247-254. doi:10.1016/j.jpain.2016.10.021 Dahlhamer J, Lucas J, Zelaya, C, et al. Prevalence of Chronic Pain and High-Impact Chronic Pain Among Adults — United States, 2016. MMWR Morb Mortal Wkly Rep . 2018;67(36):1001-1006. doi:10.15585/mmwr.mm6736a2 Rundell SD, Sherman KJ, Heagerty PJ, Mock CN, Jarvik JG. The Clinical Course of Pain and Function in Older Adults with a New Primary Care Visit for Back Pain. 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PLOS ONE . 2020;15(4):e0230751. doi:10.1371/journal.pone.0230751 Tables Table 1. Sample Characteristics (total n=342)* Response Method Paper, n(%) 269 (78.7%) Electronic (Qualtrics), n(%) 73 (21.3%) Back Pain History Duration of low back pain in years Mean (SD) 26.9 (15.9) Back pain is a problem… n(%) Every or nearly every day 229 (67.6%) At least half the days 67 (19.8%) Less than half the days 43 (12.7%) Prior back surgery, n(%) 75 (22.1%) Demographics and Comorbidities Age in years, mean (SD) 69.2 (9.1) Age 50-64 years, n(%) 92 (30.6%) Age ≥65 years, n(%) 209 (69.4%) Women, n(%) 60 (19.2%) Race, n(%)† American Indian/Alaska Native 9 (3.1%) Asian 7 (2.4%) Black/African-American 52 (17.8%) Native Hawaiian/Pacific Islander 1 (0.3%) White 234 (80.1%) Hispanic/Latino ethnicity, n(%) 16 (6.8%) BMI, mean (SD) 29.4 (5.3) Smoking history, n(%) Never smoked 112 (32.8%) Current smoker 34 (9.9%) Former smoker 164 (48.0%) Employment Status, n(%) Retired 191 (61.4%) Employed full or part-time 59 (19.0%) Disabled 50 (16.1%) Other 11 (3.5%) Education, n(%) High School diploma/GED or less 75 (23.9%) Some college, Vocational/skilled trade, or Associates degree 143 (45.7%) Bachelors, masters, or professional degree 95 (30.4%) Comorbidities, n(%) High blood pressure 224 (74.2%) Arthritis 202 (66.9%) Diabetes 116 (38.4%) Heart disease 97 (32.1%) Mental health issue 85 (28.1%) Cancer 53 (17.5%) Chronic lung disease 41 (13.6%) Weakened immune system 32 (10.6%) Stroke 24 (7.9%) Dementia 3 (1.0%) Total number of comorbidities, mean (SD) 2.9 (1.3) Function Physical Functioning‡ T-score mean (SD) 30.2 (9.9), range 8.72 – 63.0 Psychological Functioning‡ T-score mean (SD) 45.0 (13.4), range 12.7 – 73.0 Pain Characteristics Widespread Pain Index (number of painful areas) Mean (SD) 6.0 (3.8) Symptom Severity Scale Mean (SD) 5.3 (3.0) Fibromyalgia Severity Score, mean (SD) Total sample 11.3 (5.9) 50-64 years old 13.7 (6.3) ≥65 years old 10.4 (5.4) Screen positive for fibromyalgia, n(%) ‖ Total sample 112 (35.8%) 50-64 years old 44 (51.2%) ≥65 years old 58 (29.3%) Average pain intensity ¶ Mean (SD) 5.7 (2.3) Pain intensity § T-score mean (SD) 63.0 (8.2) Pain interference T-score mean (SD) 63.1 (7.4) Neuropathic pain, n(%) # Unlikely 189 (55.9%) Possible 74 (21.9%) Likely 75 (22.2%) Prescription Opioid Use Prescription opioid use for back pain, n(%) Currently Using 44 (14.0%) Used in Past 129 (41.0%) Never Used 142 (45.1%) Prescription opioid use in last year (any), n(%) 88 (27.3%) Prescription opioid use in last year for ≥3 months, n(%) 49 (15.4%) * Percentages expressed as percent of available responses, exact n varies due to missingness † Participants could select multiple races ‡ Physical and psychological functioning measured by VR-12 Physical Component Summary (PCS) and Mental Component Summary (MCS) T-scores respectively § Measured by PROMIS Short Form T-scores ‖ Via 2016 American College of Rheumatology Fibromyalgia Screening Criteria ¶ Measured with 0-10 numeric rating scale # Measured with PainDETECT questionnaire Table 2. Results of multiple linear regression* Outcome: Physical Function (VR-12 Physical Component Summary T-score) Model 1 (unadjusted) † Variable β (95% CI) SE p (intercept) 38.7 (36.4, 40.9) 1.15 <0.001** Fibromyalgia Severity Score -0.73 (-0.90, -0.56) 0.09 <0.001** Model 2 (adjusted)‡ Variable β (95% CI) SE p (intercept) 88.6 (76.4, 100.8) 6.22 <0.001** Fibromyalgia Severity Score -0.30 (-0.49, -0.12) 0.096 0.0014 # Age in years -0.11 (-0.23, 0.01) 0.063 0.083 Women (vs. men) -2.70 (-5.06, -0.35) 1.20 0.024 # Race: Black/African-American -0.22 (-2.70, 2.26) 1.26 0.861 Ethnicity: Hispanic/Latino -0.81 (-4.58, 2.96) 1.92 0.673 BMI -0.21 (-0.38, -0.04) 0.086 0.0141 # Employment Status Other reference – – Retired -4.04 (-8.95, 0.86) 2.50 0.106 Employed full or part time -0.62 (-5.74, 4.51) 2.60 0.8122 Disabled -3.27 (-8.43, 1.90) 2.63 0.2142 Number of comorbidities -1.33 (-2.02, -0.64) 0.350 <0.001** Pain intensity ¶ -0.51 (-0.63, -0.38) 0.065 <0.001** Education High School diploma/GED or less -1.95 (-4.34, 0.45) 1.22 0.1108 Some college, Vocational/skilled trade, or Associates degree -1.11 (-3.14, 0.92) 1.03 0.2836 Bachelors, masters, or professional degree reference – – Prior back surgery -2.24 (-4.30, -0.17) 1.05 0.0339 # Prescription opioid use in last year (any) -0.167 (-2.10, 1.76) 0.983 0.8657 Outcome: Psychological Function (VR-12 Mental Component Summary T-score) Model 3 (unadjusted) § Variable β (95% CI) SE p (intercept) 56.60 (53.60, 59.61) 1.53 <0.001** Fibromyalgia Severity Score -0.996 (-1.23, -0.76) 0.118 <0.001** Model 4 (adjusted) ‖ Variable β (95% CI) SE p (intercept) 60.06 (40.19, 79.94) 10.12 <0.001** Fibromyalgia Severity Score -0.64 (-0.93, -0.35) 0.150 <0.001** Age in years 0.13 (-0.084, 0.332) 0.106 0.2399 Women (vs. men) -0.53 (-4.34, 3.28) 1.93 0.7841 Race: Black/African-American 0.597 (-2.94, 4.14) 1.81 0.7409 Ethnicity: Hispanic/Latino -0.373 (-6.36, 5.62) 3.04 0.9025 BMI 0.154 (-0.11, 0.42) 0.13 0.2476 Employment Status Other reference – – Retired 5.78 (-1.64, 13.20) 3.78 0.1265 Employed full or part time 10.75 (3.26, 18.24) 3.82 0.0049 # Disabled 3.89 (-3.87, 11.64) 3.95 0.3259 Number of comorbidities -0.96 (-2.09, 0.16) 0.57 0.0921 Pain intensity ¶ -0.37 (-0.57, -0.17) 0.102 0.001** Education High School diploma/GED or less -0.52 (-4.15, 3.11) 1.85 0.7805 Some college, Vocational/skilled trade, or Associates degree -2.25 (-5.44, 0.94) 1.62 0.1672 Bachelors, masters, or professional degree reference - - Prior back surgery 1.09 (-2.10, 4.28) 1.63 0.5033 Prescription opioid use in last year (any) 0.63 (-2.50, 3.76) 1.60 0.6915 *To conduct multiple regression, the FSC method was used to impute missing values in both continuous and CLASS variables in a dataset with an arbitrary missing pattern, producing n=3,350 complete cases after 10 imputations † Model 1 R 2 0.159 – 0.183 ‡ Model 2 R 2 0.447 – 0.471 § Model 3 R 2 0.171 – 0.183 ‖ Model 4 R 2 0.268 – 0.289 ¶ Pain intensity was measured by PROMIS Pain Intensity Short Form-3 T-score. # p-value <0.05 **p-value <0.001 Additional Declarations The authors declare no competing interests. Supplementary Files AppendicesJGIM121525.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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1","display":"","copyAsset":false,"role":"figure","size":57509,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between nociplastic features and function. Shaded regions represent 95% confidence intervals. Top panel: Physical function (measured by the VR-12 PCS T-score) was poorer on average in the older (65+ years) group compared with the younger (50-64 years) group. More severe nociplastic features (as indicated by higher total fibromyalgia severity scores on the FSQ) were associated with poorer function regardless of age. Bottom panel: There was no difference in psychological function / mental health (measured by the VR-12 MCS T-score) by age group. More severe nociplastic features are also associated with poorer mental health regardless of age.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8376244/v1/e2d7b05096cde2b61f961d53.jpg"},{"id":98440126,"identity":"922f4bb5-7657-4c2d-be0b-7942280ba969","added_by":"auto","created_at":"2025-12-17 17:03:20","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":999487,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8376244/v1/3b77dacf-5689-434c-8299-0c4977b79ad5.pdf"},{"id":98379154,"identity":"7594adaa-dc46-49ea-8552-dc1cc66d237a","added_by":"auto","created_at":"2025-12-17 07:24:46","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":244461,"visible":true,"origin":"","legend":"","description":"","filename":"AppendicesJGIM121525.docx","url":"https://assets-eu.researchsquare.com/files/rs-8376244/v1/ebb8571e3f310b5189254b69.docx"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eAssociation of Nociplastic Pain Features with Function in Aging Veterans with Chronic Low Back Pain\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eChronic low back pain (CLBP) affects nearly one million US Veterans and is a common cause of functional impairment\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. Aging Veterans, especially those above 50 years old, are considerably more affected than the general population\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. Only about a quarter of older adults experience substantial improvement in back pain-related disability after a year of treatment\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. One possible explanation for failure of certain treatments may be the unrecognized presence of nociplastic features of pain. \u0026ldquo;Nociplastic\u0026rdquo; is a recently described construct intended to specify the increasingly better understood mechanism whereby altered central nervous system processing causes a shift from pain as a straightforward perception of tissue or nerve injury (nociceptive or neuropathic pain mechanisms, respectively) to a complex emotional and threatening experience\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Nociplastic mechanisms likely underlie several chronic overlapping pain conditions (COPCs), or disorders of primary pain\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. COPCs include conditions that frequently co-occur within individual patients, such as nonspecific CLBP, irritable bowel syndrome, fibromyalgia, and interstitial cystitis/bladder pain syndrome\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. In COPCs, nociceptive input (such as inflammation and arthritis) may also be present but is insufficient to explain an individual\u0026rsquo;s pain intensity and interference.\u003c/p\u003e \u003cp\u003eAccumulating evidence suggests a dose-response relationship between reporting more nociplastic features with poorer pain treatment outcomes. After undergoing surgeries intended to relieve pain, more severe nociplastic pain characteristics predict more post-operative pain and opioid use but less clinical improvement\u003csup\u003e\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. In contrast to nociceptive pain mechanisms, both targeting peripheral pain generators (for example, epidural steroid injections) and opioid therapy in patients who endorse many nociplastic pain symptoms results in poorer analgesia\u003csup\u003e\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. Rather, individuals with prominent nociplastic features may benefit more from education, psychotherapy, structured physical activity, and certain centrally-acting medications such as duloxetine\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Unfortunately, nociplastic features in aging patients may be especially underrecognized. One longitudinal study found recognition delayed for a mean of seven years\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. During this time, patients received potentially ineffective peripherally-directed treatments yet did not receive other treatments more supported by evidence. The failure to recognize and appropriately treat nociplastic features and COPCs in aging patients may predispose them to progressive functional decline, disability, and frailty.\u003c/p\u003e \u003cp\u003eHowever, it is unclear to what extent aging Veterans with CLBP, a highly prevalent COPC, report nociplastic features and whether nociplastic characteristics contribute to poorer physical and psychological function. We conducted a national survey of Veterans 50\u0026ndash;89 years old with CLBP to test the hypothesis that more nociplastic features will be associated with worse physical and psychological functioning in a dose-dependent manner, even after adjustment for factors known to be associated with more severe functional impairment from pain (e.g. prior back surgeries, comorbidities, and pain intensity). We also hypothesized that nociplastic features will be more prevalent in later middle-age (50\u0026ndash;64 years) vs older (65\u0026thinsp;+\u0026thinsp;years) patients.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e \u003cstrong\u003eStudy Population and Sample Selection\u003c/strong\u003e \u003cp\u003eUsing the Veterans Affairs Corporate Data Warehouse and the Medicare Vital Status File, we identified 450,896 living Veterans 50\u0026ndash;89 years old with at least two VA provider outpatient encounters from October 2018 to September 2022 where an ICD-10 code for low back pain (M54.5, M54.40, 41, 42, M54.89)\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e was assigned. Of those meeting selection criteria, 9.8% were women and 22% were Black/African-American (AA). The proportion of Veterans reporting Black/AA ancestry is 15.4%, and 7.4% of Veterans 50 years and older are women\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. A stratified random sampling approach oversampled women and Black/AA Veterans by a factor of 2, identifying 800 individuals to receive study invitations. Appendix 1 contains the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) study flow diagram.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eData Source\u003c/strong\u003e \u003cp\u003eStudy data was obtained via completion of a one-time survey. Participants could choose to complete it either electronically (via Qualtrics FedRAMP instance) or via paper, but were instructed to only complete the survey once. The packet included an invitational letter with opt-out instructions, a QR code linking to Qualtrics; a study information sheet; the paper survey with a prepaid return envelope; and a \u003cspan\u003e$\u003c/span\u003e10 gift card. Neither the paper survey nor the electronic version was individually linked. A reminder packet was sent four weeks later to all not opting out. The study protocol was approved by the VA Ann Arbor Healthcare System Institutional Review Board.\u003c/p\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eMeasures\u003c/h2\u003e \u003cp\u003e \u003cstrong\u003eBack PainChronicity\u003c/strong\u003e \u003cp\u003eAll information was obtained by self-report. Participants endorsing current, ongoing back pain for \u0026ge;\u0026thinsp;3 months were considered to have CLBP.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eNociplastic Characteristics\u003c/strong\u003e \u003cp\u003eFeatures consistent with a nociplastic pain mechanism were assessed using the Fibromyalgia Survey Questionnaire (FSQ), an adaptation of the American College of Rheumatology (ACR) fibromyalgia survey criteria for survey research\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. The FSQ assesses pain widespreadedness (Widespread Pain Index [WPI]) by asking participants to specify discrete body pain location(s). The Symptom Severity score (SSS) assesses additional co-occurring symptoms such as fatigue and trouble thinking or remembering. The total Fibromyalgia Severity (FS) score is the sum of the WPI and SSS, ranging from 0 (symptoms absent) to 31 (most severe)\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Respondents were considered to screen positive for fibromyalgia if they met 2016 ACR diagnostic criteria of WPI\u0026thinsp;\u0026ge;\u0026thinsp;7 and SSS\u0026thinsp;\u0026ge;\u0026thinsp;5 \u003cem\u003eor\u003c/em\u003e WPI 4\u0026ndash;6 and SSS\u0026thinsp;\u0026ge;\u0026thinsp;9\u003csup\u003e19\u003c/sup\u003e. We used this instrument both to ascertain those with severe nociplastic features (defined as meeting ACR fibromyalgia screening criteria) and as a continuous measure allowing capture of those with clinically important nociplastic features not necessarily meeting a cutpoint (i.e., subthreshold symptoms). This methodology has been used in multiple studies of chronic pain populations not otherwise diagnosed with fibromyalgia, including CLBP, finding dose-dependent relationships with higher FSQ scores predictive of more disability, more opioid use (but poorer response to opioids), and poorer response to procedures intended to relieve pain, such as surgery or steroid injections\u003csup\u003e\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e,\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eFunction\u003c/strong\u003e \u003cp\u003eThe Veterans RAND 12-Item Health Survey (VR-12) is a general measure of overall function and well-being extensively used in Veteran research and clinical applications\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. The VR-12 Physical (PCS) and Mental Component Summary (MCS) scores assess physical and psychological function, respectively. Scores are standardized and normed to Veteran populations, with lower indicating poorer self-perception of overall function and well-being.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eAdditional Measures\u003c/strong\u003e \u003cp\u003eSociodemographic data obtained included age, gender, ethnicity, race, education level, employment status, tobacco use, weight, and height (to calculate body mass index [BMI]). Items adapted from the Health and Retirement Study\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e assessed the presence of comorbid conditions. An adapted questionnaire\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e was used to assess surgical and opioid use history. Patient Reported Outcomes Measurement and Information System (PROMIS) short forms assessed pain intensity and interference. The PainDETECT questionnaire was used to ascertain likelihood of neuropathic mechanisms contributing to back pain\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eData Handling and Analysis\u003c/strong\u003e \u003cp\u003ePaper survey data was double-coded and entered by two individuals then combined with Qualtrics data. Respondents without current CLBP were excluded from further analyses. Ambiguous paper survey responses (e.g. selection of multiple adjacent responses) were assigned one response via a random probability generator. For example, if a participant circled both \u0026ldquo;4\u0026rdquo; and \u0026ldquo;5\u0026rdquo; on a Likert scale, a random probability was generated; if\u0026thinsp;\u0026ge;\u0026thinsp;0.5, the response was coded as the higher value. Mutually exclusive responses (e.g. both \u0026ldquo;yes\u0026rdquo; and \u0026ldquo;no\u0026rdquo;) were coded as missing.\u003c/p\u003e \u003c/p\u003e \u003cp\u003eThe HealthMeasures Scoring Service\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e was used to generate standardized T-scores for PROMIS items. VR-12 data was scored using tool developers\u0026rsquo; recommended code which produces a single imputation as long as a single item is non-missing\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. Missing values in other variables were treated as missing at random. Missingness ranged from \u0026lt;\u0026thinsp;1% to 31%. Most items contained\u0026thinsp;\u0026lt;\u0026thinsp;10% missing (Appendix 2). Descriptive analyses were performed on sample data. The PROC MI procedure in SAS version 9.4 (SAS Institute, Inc., Cary, NC) was used to generate and analyze 10 datasets with no missing values, imputed using fully conditional specification (FCS)\u003csup\u003e\u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. All inferential analyses were performed on the imputed dataset. To characterize the association of nociplastic features with functioning, we constructed multiple linear regression models adjusting for age, gender, race, ethnicity, employment, education, history of back surgery, BMI, number of comorbidities, pain intensity, and prescription opioid use. R\u003csup\u003e2\u003c/sup\u003e values were used to assess goodness-of-fit\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. The MI estimate of each statistic of interest in the regression models was calculated by averaging across the 10 imputed datasets according to Rubin\u0026rsquo;s rules\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eIn total, 361 surveys were returned or completed electronically (45.1% response rate). After excluding those without CLBP (n=19), the final sample contained 342 veterans who reported experiencing back pain for nearly 27 years on average. Most (86.5%) indicated back pain was a problem at least half the days in the past 6 months. The proportion of women (19.2%) and Black/AA (17.8%) respondents indicated adequate representation. Prescribed opioids were used by 14.0% for back pain specifically. Nearly one-third reported at least some prescribed opioid use in the last year, and approximately 15% used prescribed opioids long-term (≥3 months).\u0026nbsp;Comorbidities were common, with hypertension and arthritis most frequently reported. Table 1 details respondent characteristics.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eNociplastic Features:\u003c/em\u003e Participants experienced pain in a mean of 6 (SD 3.8) discrete locations, though there was marked variability (range 0-18, median 5, IQR 3-8). The fibromyalgia severity score mean was 11.3 (SD 5.9) with a similarly wide distribution (range 0-28, median 11, IQR 7-15). When grouped by age, respondents aged 50-64 years had fibromyalgia severity scores that were 3.3 points higher on average than those 65 years and older. Overall, 36% reported nociplastic features severe enough to meet 2016 ACR fibromyalgia diagnostic criteria. However, 51% of the younger group met criteria compared to just 29% of the older respondents.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFunction\u003c/em\u003e: On average, self-assessment of physical function was very poor, two SD below population norms (PCS T-score mean 30.2, SD 9.9). Respondents’ psychological status fared better; the MCS T-score mean of 45 (SD 13.4) was closer to the population average.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAdditional Pain Characteristics:\u0026nbsp;\u003c/em\u003eAverage pain intensity was 5.7/10 (SD 2.3) but ranged from 0 (no pain) –10 (worst pain imaginable). Both pain intensity and interference were severe in many cases, with mean T-scores greater than a standard deviation above population average. Slightly fewer than half reported back pain with likely or possible neuropathic features.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eRelationship of\u0026nbsp;\u003c/em\u003e\u003cem\u003eNociplastic\u0026nbsp;Features with\u0026nbsp;Function:\u0026nbsp;\u003c/em\u003eDetails of regression analyses are presented in Table 2. Ten imputations produced n=3,350 complete cases available for analysis. Higher fibromyalgia severity scores (indicating more severe nociplastic features) were associated with lower significantly poorer physical function (β -0.03 (95% CI -0.49, -0.12), p=0.0014) and psychological function (β -0.64 (95% CI -0.93, -0.35), p\u0026lt;0.001), after adjusting for sociodemographic factors, pain intensity, surgical history, and opioid use.Altogether, more nociplastic features, higher pain intensity, higher BMI, more comorbidities, woman gender, and history of back surgery were significantly associated with poorer physical function (lower VR-12 PCS T-scores). Nociplastic features, higher pain intensity, and employment status other than employed full/part-time were significantly associated with poorer psychological function (lower VR-12 MCS T-scores). When grouped by younger age (50-64 years) vs older (≥65 years), younger respondents had significantly higher mean fibromyalgia severity scores (mean 13.6 (SD 5.9) vs 10.8 (SD 5.3), \u003cem\u003et\u003c/em\u003e(1795.1) = 13.18, \u003cem\u003ep\u003c/em\u003e\u0026lt;.001). However, the directionality and slope of the relationship were not significantly different in the adjusted model; higher fibromyalgia severity scores were associated with poorer overall function regardless of age (Figure 1). \u0026nbsp;A sensitivity analysis of complete cases from the sample produced similar results (Appendix 3).\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this national sample of Veterans 50 years and older with CLBP, reporting features consistent with a nociplastic mechanism of pain (e.g., widespread pain and concurrent mood and sleep disturbance) robustly associated with poorer overall function. This dose-response relationship remained significant after controlling for sociodemographic and clinical factors known to associate with poorer functioning, such as older age. More than a third reported nociplastic features severe enough to meet diagnostic criteria for fibromyalgia, the prototypical nociplastic pain disorder, though the proportion was considerably higher among younger respondents. Despite sample selection based only on a single site of pain, participants reported experiencing six distinct painful sites on average, suggesting that multiple chronic pain conditions may be present in aging Veterans with CLBP. Notably, a minority of participants reported no or very few nociplastic characteristics, including localized back pain.\u003c/p\u003e \u003cp\u003eChronic nonspecific low back pain is one of multiple COPCs where nociplastic pain is considered the predominant pain mechanism. In these conditions, other pain mechanisms may be present, but they do not fully capture the pain experience either in severity or functional interference\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. COPCs, including fibromyalgia, CLBP, and irritable bowel syndrome among others, are termed such because they commonly co-occur within individuals. The widespread pain in this national sample suggests the presence of additional COPCs in late middle-aged and older Veterans with CLBP. In this sample, nociplastic features were common, and in a significant minority, they were very severe. Similar to prior studies\u003csup\u003e\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e, we benchmarked \u0026ldquo;severe\u0026rdquo; nociplastic features as those meeting 2016 ACR fibromyalgia screening criteria. The chronic, multisite pain experienced by patients with fibromyalgia, a condition defined by pain co-occurring alongside symptoms of fatigue, dyscognition, and unrefreshing sleep, is a prototypical example of the \u0026ldquo;nociplastic\u0026rdquo; pain category, a term coined to distinguish it from nociceptive and neuropathic pain\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. When survey instruments are used to screen for fibromyalgia, prevalence ranges from 2\u0026ndash;4% (general or non-clinical populations) to above 40% (patients presenting to a tertiary back pain clinic).\u003csup\u003e\u003cspan additionalcitationids=\"CR30\" citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e Similar to our findings, younger age, unemployment, higher pain severity, and poorer physical function were all associated with screening positive.\u003c/p\u003e \u003cp\u003ePrior investigation into nociplastic characteristics among older veterans with CLBP has been extremely limited. One small study of Veterans\u0026thinsp;\u0026gt;\u0026thinsp;65 years old noted a prevalence of approximately 25%\u003csup\u003e30\u003c/sup\u003e. Our finding a prevalence of about 35% may relate to our sample\u0026rsquo;s relatively younger mean age; indeed, when divided into younger (50\u0026ndash;64 years) and older (\u0026ge;\u0026thinsp;65 years) respondents, prevalence was significantly higher in the younger group. Overall, patients with CLBP may have more prevalent and severe nociplastic features than in certain other chronic pain states. For example, only 8\u0026ndash;9% of patients presenting for surgeries intended to relieve pain screen positive for fibromyalgia, indicating severe nociplastic features may be less prevalent\u003csup\u003e\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Our findings support that persistent, nonspecific back pain is a disorder of primary pain rather than a result of peripheral pathology, such as degenerative changes seen on imaging.\u003c/p\u003e \u003cp\u003eClinically, nociplastic characteristics are important to recognize because their presence predicts poorer response to certain common treatments, especially those aimed at addressing peripheral pain generators as would be appropriate for nociceptive pain. For example, in patients undergoing surgery to relieve a painful condition (e.g. knee replacement, hysterectomy), reporting more nociplastic features predicts more post-operative pain, more opioid use, and less overall improvement\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. In clinical trials of medial branch blocks and steroid injections, treatments aimed at addressing peripheral targets, participants with symptoms consistent with a nociplastic pain mechanism experience poorer outcomes\u003csup\u003e\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan additionalcitationids=\"CR34\" citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eEncouragingly, patients with prominent nociplastic features can benefit from targeted treatment. Grounded in a trusted clinician-patient relationship, multimodal approaches featuring both pharmacologic and behavioral treatments may be helpful\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. In older adults, recognizing nociplastic features when seeking treatment for pain may be especially important to prevent or mitigate functional decline and frailty. Our findings suggest that older Veterans, especially those\u0026thinsp;\u0026ge;\u0026thinsp;65 years, have somewhat less severe nociplastic features on average than those in the 50\u0026ndash;64 year age range. However, when nociplastic features are present, the association with poor function is no less prominent. Unfortunately, nociplastic features are likely underrecognized in older adults; one study\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e found that participants\u0026thinsp;\u0026ge;\u0026thinsp;55 years old reported symptoms an average of seven years before eventually receiving an appropriate fibromyalgia diagnosis. During that time, they received non-targeted treatments that were ineffective and potentially harmful.\u003c/p\u003e \u003cp\u003eThough effective treatments for patients with prominent nociplastic features exist, precise recognition of pain mechanism(s) in any individual patient remains a matter of some debate. Recently, a stepped algorithmic approach to identifying nociplastic pain was recommended\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e, necessitating that pain must be chronic, widespread, and accompanied by central symptoms. Moreover, this approach requires the presence of sensory hypersensitivity, either assessed through a clinical history or evoked hypersensitivity testing. The instrument used in this study to assess nociplastic features does not explicitly ascertain hypersensitivity. However, the FSQ has been used as a continuous measure in multiple studies finding similarly that higher scores (indicating higher likelihood and severity of nociplastic pain) are associated with poorer functional outcomes\u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. The FSQ has several advantages, including brevity; it can be administered during routine clinical encounters and provide actionable information for clinical decision-making.\u003c/p\u003e \u003cp\u003eThis study has several limitations. As a cross-sectional survey, no causal conclusions can be made regarding the association with nociplastic features and poorer function. The survey response rate (45.1%), while higher than other mailout surveys of Veterans with CLBP\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e, is less than recent surveys using mixed-mode mail and phone follow up methods\u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e. There is the possibility of recall bias and unmeasured confounding. As survey responses were anonymous, it is not possible to know whether respondents completed the survey multiple times. However, we believe that this occurring frequently enough to skew results is unlikely.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eOur findings support that in aging Veterans with chronic low back pain, characteristics of nociplastic pain are common. Among those aged 50\u0026ndash;64 years, nociplastic features may be more prevalent and severe than later in life. When examined along a continuum, there was a strong association with reporting more pronounced nociplastic attributes and poorer self-perception of overall physical and psychological function and well-being. Future investigations, including clinical trials of new pain interventions, should examine nociplastic features to determine the efficacy of novel treatments in this important but understudied group.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eContributors\u003c/em\u003e: We gratefully acknowledge the following research staff for assistance with data collection and entry: Marian Gelani, Jennifer Caldararo, and Elizabeth Firsht.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFunders\u003c/em\u003e:\u0026nbsp;Dr. Powell, Dr. Ha, Dr. Silveira, and Dr. Galecki received support from the National Institute on Aging (5P30AG024824-20, 5T32AG062403; 3T32AG062403-03S1). Dr. Ha and Dr. Powell received support from the Department of Veterans Affairs (VA) through a Pain Opioid CORE Rapid Start grant. Dr. Powell is supported by a VA Career Development Award (1IK2CX002646-01A2). \u0026nbsp; Dr. Krein is supported by a VA research career scientist award (RCS 11-222).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePrior presentations:\u003c/em\u003e Portions of this work have been presented at the Gerontological Society of America 2025 annual meeting, University of Michigan Pepper Center Research Education Core conference (2023), University of Michigan Palliative Care Research Seminar (2023), and the Pain Opioid CORE Career Development Workgroup (2023).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u0026nbsp;Conflicts of Interest\u003c/em\u003e\u003cstrong\u003e:\u0026nbsp;\u003c/strong\u003eDr. Clauw\u0026nbsp;reports grants and personal fees from Tonix and personal fees from Axsome and Merck.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eNahin RL. Severe Pain in Veterans: The Impact of Age and Sex, and Comparisons to the General Population. \u003cem\u003eJ Pain\u003c/em\u003e. 2017;18(3):247-254. doi:10.1016/j.jpain.2016.10.021\u003c/li\u003e\n \u003cli\u003eDahlhamer J, Lucas J, Zelaya, C, et al. Prevalence of Chronic Pain and High-Impact Chronic Pain Among Adults \u0026mdash; United States, 2016. \u003cem\u003eMMWR Morb Mortal Wkly Rep\u003c/em\u003e. 2018;67(36):1001-1006. doi:10.15585/mmwr.mm6736a2\u003c/li\u003e\n \u003cli\u003eRundell SD, Sherman KJ, Heagerty PJ, Mock CN, Jarvik JG. The Clinical Course of Pain and Function in Older Adults with a New Primary Care Visit for Back Pain. \u003cem\u003eJ American Geriatrics Society\u003c/em\u003e. 2015;63(3):524-530. doi:10.1111/jgs.13241\u003c/li\u003e\n \u003cli\u003eKosek E, Clauw D, Nijs J, et al. Chronic nociplastic pain affecting the musculoskeletal system: clinical criteria and grading system. \u003cem\u003ePain\u003c/em\u003e. 2021;162(11):2629-2634. doi:10.1097/j.pain.0000000000002324\u003c/li\u003e\n \u003cli\u003eFitzcharles MA, Cohen SP, Clauw DJ, Littlejohn G, Usui C, H\u0026auml;user W. Nociplastic pain: towards an understanding of prevalent pain conditions. \u003cem\u003eThe Lancet\u003c/em\u003e. 2021;397(10289):2098-2110. doi:10.1016/S0140-6736(21)00392-5\u003c/li\u003e\n \u003cli\u003eKaplan CM, Kelleher E, Irani A, Schrepf A, Clauw DJ, Harte SE. Deciphering nociplastic pain: clinical features, risk factors and potential mechanisms. \u003cem\u003eNat Rev Neurol\u003c/em\u003e. 2024;20(6):347-363. doi:10.1038/s41582-024-00966-8\u003c/li\u003e\n \u003cli\u003eBrummett CM, Urquhart AG, Hassett AL, et al. Characteristics of Fibromyalgia Independently Predict Poorer Long‐Term Analgesic Outcomes Following Total Knee and Hip Arthroplasty. \u003cem\u003eArthritis \u0026amp; Rheumatology\u003c/em\u003e. 2015;67(5):1386-1394. doi:10.1002/art.39051\u003c/li\u003e\n \u003cli\u003eJanda AM, As-Sanie S, Rajala B, et al. Fibromyalgia Survey Criteria Are Associated with Increased Postoperative Opioid Consumption in Women Undergoing Hysterectomy. \u003cem\u003eAnesthesiology\u003c/em\u003e. 2015;122(5):1103-1111. doi:10.1097/ALN.0000000000000637\u003c/li\u003e\n \u003cli\u003eBrummett CM, Janda AM, Schueller CM, et al. Survey Criteria for Fibromyalgia Independently Predict Increased Postoperative Opioid Consumption after Lower-extremity Joint Arthroplasty: A Prospective, Observational Cohort Study. \u003cem\u003eAnesthesiology\u003c/em\u003e. 2013;119(6):1434-1443. doi:10.1097/ALN.0b013e3182a8eb1f\u003c/li\u003e\n \u003cli\u003eJamison RN, Edwards RR, Liu X, et al. Relationship of Negative Affect and Outcome of an Opioid Therapy Trial Among Low Back Pain Patients. \u003cem\u003ePain Practice\u003c/em\u003e. 2013;13(3):173-181. doi:10.1111/j.1533-2500.2012.00575.x\u003c/li\u003e\n \u003cli\u003eKarp JF, Yu L, Friedly J, Amtmann D, Pilkonis PA. Negative Affect and Sleep Disturbance May Be Associated With Response to Epidural Steroid Injections for Spine-Related Pain. \u003cem\u003eArchives of Physical Medicine and Rehabilitation\u003c/em\u003e. 2014;95(2):309-315. doi:10.1016/j.apmr.2013.09.007\u003c/li\u003e\n \u003cli\u003eEdwards RR, Dworkin RH, Turk DC, et al. Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations. \u003cem\u003ePain\u003c/em\u003e. 2016;157(9):1851-1871. doi:10.1097/j.pain.0000000000000602\u003c/li\u003e\n \u003cli\u003eJacobson SA, Simpson RG, Lubahn C, et al. Characterization of fibromyalgia symptoms in patients 55\u0026ndash;95 years old: a longitudinal study showing symptom persistence with suboptimal treatment. \u003cem\u003eAging Clin Exp Res\u003c/em\u003e. 2015;27(1):75-82. doi:10.1007/s40520-014-0238-7\u003c/li\u003e\n \u003cli\u003eSchrepf A, Phan V, Clemens JQ, Maixner W, Hanauer D, Williams DA. ICD-10 Codes for the Study of Chronic Overlapping Pain Conditions in Administrative Databases. \u003cem\u003eThe Journal of Pain\u003c/em\u003e. 2020;21(1-2):59-70. doi:10.1016/j.jpain.2019.05.007\u003c/li\u003e\n \u003cli\u003eHealth and Retirement Study ([HRS Core]) public use dataset. Published online 2025. https://hrs.isr.umich.edu/\u003c/li\u003e\n \u003cli\u003eBelitskaya-Levy I, Clark D, Shih MC, Bair M. Treatment Preferences for Chronic Low Back Pain: Views of Veterans and Their Providers. \u003cem\u003eJPR\u003c/em\u003e. 2021;Volume 14:161-171. doi:10.2147/JPR.S290400\u003c/li\u003e\n \u003cli\u003eIqbal, SU, Rogers, W, Selim, A, Qian, S, Lee, A, Ren, XS, Rothendler, JD, Miller, D, Kazis LE. The Veterans RAND 12 Item Health Suvery (VR-12): What It Is and How It Is Used.; 2007. https://www.bu.edu/sph/files/2015/01/veterans_rand_12_item_health_survey_vr-12_2007.pdf.\u003c/li\u003e\n \u003cli\u003eWolfe F, Clauw DJ, Fitzcharles MA, et al. Fibromyalgia Criteria and Severity Scales for Clinical and Epidemiological Studies: A Modification of the ACR Preliminary Diagnostic Criteria for Fibromyalgia. \u003cem\u003eJ Rheumatol\u003c/em\u003e. 2011;38(6):1113-1122. doi:10.3899/jrheum.100594\u003c/li\u003e\n \u003cli\u003eWolfe F, Clauw DJ, Fitzcharles MA, et al. 2016 Revisions to the 2010/2011 fibromyalgia diagnostic criteria. \u003cem\u003eSeminars in Arthritis and Rheumatism\u003c/em\u003e. 2016;46(3):319-329. doi:10.1016/j.semarthrit.2016.08.012\u003c/li\u003e\n \u003cli\u003eHolman A, Parikh ND, Zhao Z, et al. Association between widespread pain and associated symptoms in patients with cirrhosis. \u003cem\u003eHepatology Communications\u003c/em\u003e. 2023;7(5). doi:10.1097/HC9.0000000000000120\u003c/li\u003e\n \u003cli\u003eNeville SJ, Clauw AD, Moser SE, et al. Association Between the 2011 Fibromyalgia Survey Criteria and Multisite Pain Sensitivity in Knee Osteoarthritis. \u003cem\u003eThe Clinical Journal of Pain\u003c/em\u003e. 2018;34(10):909-917. doi:10.1097/AJP.0000000000000619\u003c/li\u003e\n \u003cli\u003eFreynhagen R, Baron R, Gockel U, T\u0026ouml;lle TR. pain \u003cem\u003eDETECT\u003c/em\u003e : a new screening questionnaire to identify neuropathic components in patients with back pain. \u003cem\u003eCurrent Medical Research and Opinion\u003c/em\u003e. 2006;22(10):1911-1920. doi:10.1185/030079906X132488\u003c/li\u003e\n \u003cli\u003eAssessment Center. HealthMeasures Scoring Service. Published online 2025. https://www.assessmentcenter.net/ac_scoringservice\u003c/li\u003e\n \u003cli\u003eVan Buuren S, Groothuis-Oudshoom K. MICE:Multivariate imputation by chained equations in R. \u003cem\u003eJ Stat Software\u003c/em\u003e. Published online 2011.\u003c/li\u003e\n \u003cli\u003eVan Buuren S. Multiple imputation of discrete and continuous data by fully conditional specification. \u003cem\u003eStat Methods Med Res\u003c/em\u003e. 2007;16(3):219-242. doi:10.1177/0962280206074463\u003c/li\u003e\n \u003cli\u003eRubin DB. Multiple Imputation for Survey Nonresponse. John Wiley \u0026amp; Sons; 1987.\u003c/li\u003e\n \u003cli\u003eVan Ginkel JR. Significance Tests and Estimates for \u003cem\u003eR\u003c/em\u003e\u003csup\u003e2\u003c/sup\u003e for Multiple Regression in Multiply Imputed Datasets: A Cautionary Note on Earlier Findings, and Alternative Solutions. \u003cem\u003eMultivariate Behavioral Research\u003c/em\u003e. 2019;54(4):514-529. doi:10.1080/00273171.2018.1540967\u003c/li\u003e\n \u003cli\u003eMaixner W, Fillingim RB, Williams DA, Smith SB, Slade GD. Overlapping Chronic Pain Conditions: Implications for Diagnosis and Classification. \u003cem\u003eThe Journal of Pain\u003c/em\u003e. 2016;17(9):T93-T107. doi:10.1016/j.jpain.2016.06.002\u003c/li\u003e\n \u003cli\u003eH\u0026auml;user W, Br\u0026auml;hler E, Ablin J, Wolfe F. Modified 2016 American College of Rheumatology Fibromyalgia Criteria, the Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks\u0026ndash;American Pain Society Pain Taxonomy, and the Prevalence of Fibromyalgia. \u003cem\u003eArthritis Care \u0026amp;amp; Research\u003c/em\u003e. 2021;73(5):617-625. doi:10.1002/acr.24202\u003c/li\u003e\n \u003cli\u003eWeiner DK, Gentili A, Rossi M, et al. Aging Back Clinics\u0026mdash;a Geriatric Syndrome Approach to Treating Chronic Low Back Pain in Older Adults: Results of a Preliminary Randomized Controlled Trial. \u003cem\u003ePain Medicine\u003c/em\u003e. 2020;21(2):274-290. doi:10.1093/pm/pnz179\u003c/li\u003e\n \u003cli\u003eClauw DJ. Fibromyalgia: A Clinical Review. \u003cem\u003eJAMA\u003c/em\u003e. 2014;311(15):1547. doi:10.1001/jama.2014.3266\u003c/li\u003e\n \u003cli\u003eAs-Sanie S, Till SR, Mowers EL, et al. Opioid Prescribing Patterns, Patient Use, and Postoperative Pain After Hysterectomy for Benign Indications. \u003cem\u003eObstetrics \u0026amp; Gynecology\u003c/em\u003e. 2017;130(6):1261-1268. doi:10.1097/AOG.0000000000002344\u003c/li\u003e\n \u003cli\u003eAblin JN, Berman M, Aloush V, et al. Effect of Fibromyalgia Symptoms on Outcome of Spinal Surgery. \u003cem\u003ePain Medicine\u003c/em\u003e. 2017;18(4):773-780. doi:10.1093/pm/pnw232\u003c/li\u003e\n \u003cli\u003eWasserman RA, Brummett CM, Goesling J, Tsodikov A, Hassett AL. Characteristics of Chronic Pain Patients Who Take Opioids and Persistently Report High Pain Intensity: \u003cem\u003eRegional Anesthesia and Pain Medicine\u003c/em\u003e. 2014;39(1):13-17. doi:10.1097/AAP.0000000000000024\u003c/li\u003e\n \u003cli\u003eKoffel E, Kats AM, Kroenke K, et al. Sleep Disturbance Predicts Less Improvement in Pain Outcomes: Secondary Analysis of the SPACE Randomized Clinical Trial. \u003cem\u003ePain Med\u003c/em\u003e. 2020;21(6):1162-1167. doi:10.1093/pm/pnz221\u003c/li\u003e\n \u003cli\u003eMueller BR, Clauw DJ, De Lott LB. Advances in Our Understanding and Treatment of Nociplastic Pain. \u003cem\u003eNeurol Clin\u003c/em\u003e. 2025;43(3):549-560. doi:10.1016/j.ncl.2025.04.005\u003c/li\u003e\n \u003cli\u003eH\u0026auml;user W, Jung E, Erbsl\u0026ouml;h-M\u0026ouml;ller B, et al. Validation of the Fibromyalgia Survey Questionnaire within a Cross-Sectional Survey. Baradaran HR, ed. \u003cem\u003ePLoS ONE\u003c/em\u003e. 2012;7(5):e37504. doi:10.1371/journal.pone.0037504\u003c/li\u003e\n \u003cli\u003eKrebs EE, Clothier B, Nugent S, et al. The evaluating prescription opioid changes in veterans (EPOCH) study: Design, survey response, and baseline characteristics. \u003cem\u003ePLOS ONE\u003c/em\u003e. 2020;15(4):e0230751. doi:10.1371/journal.pone.0230751\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1.\u0026nbsp;\u003c/strong\u003eSample Characteristics (total n=342)*\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"753\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eResponse Method\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp;Paper, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e269 (78.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp;Electronic (Qualtrics), n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e73 (21.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBack Pain History\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cp\u003eDuration of low back pain in years\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Mean (SD)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e26.9 (15.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cp\u003eBack pain is a problem\u0026hellip; \u0026nbsp;n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Every or nearly every day\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e229 (67.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; At least half the days\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e67 (19.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Less than half the days\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e43 (12.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003ePrior back surgery, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e75 (22.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDemographics and Comorbidities\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eAge in years, mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e69.2 (9.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eAge 50-64 years, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e92 (30.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp;Age \u0026ge;65 years, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e209 (69.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eWomen, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e60 (19.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eRace, \u0026nbsp;n(%)\u0026dagger;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; American Indian/Alaska Native\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e9 (3.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Asian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e7 (2.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Black/African-American\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e52 (17.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Native Hawaiian/Pacific Islander\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e1 (0.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; White\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e234 (80.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eHispanic/Latino ethnicity, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e16 (6.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eBMI, mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e29.4 (5.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eSmoking history, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Never smoked\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e112 (32.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Current smoker\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e34 (9.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Former smoker\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e164 (48.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eEmployment Status, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Retired\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e191 (61.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Employed full or part-time\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e59 (19.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Disabled\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e50 (16.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Other\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e11 (3.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eEducation, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; High School diploma/GED or less\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e75 (23.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Some college, Vocational/skilled trade, or Associates degree\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e143 (45.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Bachelors, masters, or professional degree\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e95 (30.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eComorbidities, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; High blood pressure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e224 (74.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Arthritis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e202 (66.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Diabetes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e116 (38.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Heart disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e97 (32.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Mental health issue\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e85 (28.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Cancer\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e53 (17.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Chronic lung disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e41 (13.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Weakened immune system\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e32 (10.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Stroke\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e24 (7.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Dementia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e3 (1.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Total number of comorbidities, mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e2.9 (1.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFunction\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003ePhysical Functioning\u0026Dagger;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; T-score mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e30.2 (9.9), range 8.72 \u0026ndash; 63.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003ePsychological Functioning\u0026Dagger;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; T-score mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e45.0 (13.4), range 12.7 \u0026ndash; 73.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePain Characteristics\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eWidespread Pain Index (number of painful areas)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e6.0 (3.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eSymptom Severity Scale\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e5.3 (3.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eFibromyalgia Severity Score, mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Total sample\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e11.3 (5.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; 50-64 years old\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e13.7 (6.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026ge;65 years old\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e10.4 (5.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eScreen positive for fibromyalgia, n(%) ‖\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Total sample\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e112 (35.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;50-64 years old\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e44 (51.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;\u0026ge;65 years old\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e58 (29.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eAverage pain intensity \u0026para;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e5.7 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003ePain intensity \u0026sect;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; T-score mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e63.0 (8.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003ePain interference\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; T-score mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e63.1 (7.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003eNeuropathic pain, n(%)\u0026nbsp;#\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp;Unlikely\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e189 (55.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp;Possible\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e74 (21.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp;Likely\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e75 (22.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrescription Opioid Use\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003ePrescription opioid use for back pain, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Currently Using\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e\u0026nbsp;44 (14.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Used in Past\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e129 (41.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003e\u0026nbsp; Never Used\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e142 (45.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003ePrescription opioid use in last year (any), n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e88 (27.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 53.3865%;\"\u003e\n \u003cp\u003ePrescription opioid use in last year for \u0026ge;3 months, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 46.6135%;\"\u003e\n \u003cp\u003e49 (15.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cp\u003e* Percentages expressed as percent of available responses, exact n varies due to missingness\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026dagger; Participants could select multiple races\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cp\u003e\u0026Dagger; \u0026nbsp;Physical and psychological functioning measured by VR-12 Physical Component Summary (PCS) and Mental Component Summary (MCS) T-scores respectively\u003c/p\u003e\n \u003cp\u003e\u0026sect;\u0026nbsp;Measured by PROMIS Short Form T-scores\u003c/p\u003e\n \u003cp\u003e‖ \u0026nbsp;Via 2016 American College of Rheumatology Fibromyalgia Screening Criteria\u003c/p\u003e\n \u003cp\u003e\u0026para; Measured with 0-10 numeric rating scale\u003c/p\u003e\n \u003cp\u003e# Measured with PainDETECT questionnaire\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"707\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 2.\u003c/strong\u003e Results of multiple linear regression*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable class=\"MsoNormalTable\" border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"710\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 710px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eOutcome: \u0026nbsp;Physical Function (VR-12 Physical Component Summary T-score)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 710px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eModel 1 (unadjusted)\u003c/span\u003e\u003c/strong\u003e\u003cspan lang=\"EN\"\u003e\u0026dagger;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eVariable\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003e\u0026beta; (95% CI)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eSE\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan lang=\"EN\"\u003ep\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e(intercept)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e38.7 (36.4, 40.9)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.15\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026lt;0.001**\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eFibromyalgia Severity Score\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.73 (-0.90, -0.56)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.09\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026lt;0.001**\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 710px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eModel 2 (adjusted)\u0026Dagger;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eVariable\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003e\u0026beta; (95% CI)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eSE\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan lang=\"EN\"\u003ep\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e(intercept)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e88.6 (76.4, 100.8)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e6.22\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026lt;0.001**\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eFibromyalgia Severity Score\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.30 (-0.49, -0.12)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.096\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.0014\u0026nbsp;\u003c/span\u003e\u003cspan lang=\"EN\"\u003e#\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eAge in years\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.11 (-0.23, 0.01)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.063\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.083\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eWomen (vs. men)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-2.70 (-5.06, -0.35)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.20\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.024\u0026nbsp;\u003c/span\u003e\u003cspan lang=\"EN\"\u003e#\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eRace: Black/African-American\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.22 (-2.70, 2.26)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.26\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.861\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eEthnicity: Hispanic/Latino\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.81 (-4.58, 2.96)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.92\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.673\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eBMI\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.21 (-0.38, -0.04)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.086\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.0141\u0026nbsp;\u003c/span\u003e\u003cspan lang=\"EN\"\u003e#\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 710px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eEmployment Status\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; \u0026nbsp;Other\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003ereference\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026ndash;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026ndash;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; \u0026nbsp;Retired\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-4.04 (-8.95, 0.86)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e2.50\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.106\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; \u0026nbsp;Employed full or part time\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.62 (-5.74, 4.51)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e2.60\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.8122\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; \u0026nbsp;Disabled\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-3.27 (-8.43, 1.90)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e2.63\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.2142\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eNumber of comorbidities\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-1.33 (-2.02, -0.64)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.350\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026lt;0.001**\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003ePain intensity\u003csup\u003e\u0026nbsp;\u003c/sup\u003e\u003c/span\u003e\u003cspan lang=\"EN\"\u003e\u0026para;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.51 (-0.63, -0.38)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.065\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026lt;0.001**\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 710px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eEducation\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; High School diploma/GED or less\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-1.95 (-4.34, 0.45)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.22\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.1108\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; Some college, Vocational/skilled trade, or Associates degree\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-1.11 (-3.14, 0.92)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.03\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.2836\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; Bachelors, masters, or professional degree\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003ereference\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026ndash;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026ndash;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003ePrior back surgery\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-2.24 (-4.30, -0.17)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.05\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.0339\u0026nbsp;\u003c/span\u003e\u003cspan lang=\"EN\"\u003e#\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003ePrescription opioid use in last year (any)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.167 (-2.10, 1.76)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.983\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.8657\u003c/span\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 710px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eOutcome: Psychological Function (VR-12 Mental Component Summary T-score)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 710px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eModel 3 (unadjusted)\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003cspan lang=\"EN\"\u003e\u0026sect;\u003c/span\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eVariable\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003e\u0026beta; (95% CI)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eSE\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan lang=\"EN\"\u003ep\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e(intercept)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e56.60 (53.60, 59.61)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.53\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026lt;0.001**\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eFibromyalgia Severity Score\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.996 (-1.23, -0.76)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.118\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026lt;0.001**\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 710px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eModel 4 (adjusted)\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003cspan lang=\"EN\"\u003e‖\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eVariable\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003e\u0026beta; (95% CI)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN\"\u003eSE\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan lang=\"EN\"\u003ep\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e(intercept)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e60.06 (40.19, 79.94)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e10.12\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026lt;0.001**\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eFibromyalgia Severity Score\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.64 (-0.93, -0.35)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.150\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026lt;0.001**\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eAge in years\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.13 (-0.084, 0.332)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.106\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.2399\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eWomen (vs. men)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.53 (-4.34, 3.28)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.93\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.7841\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eRace: Black/African-American\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.597 (-2.94, 4.14)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.81\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.7409\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eEthnicity: Hispanic/Latino\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.373 (-6.36, 5.62)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e3.04\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.9025\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eBMI\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.154 (-0.11, 0.42)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.13\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.2476\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 710px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eEmployment Status\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; \u0026nbsp; Other\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003ereference\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026ndash;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026ndash;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; \u0026nbsp; Retired\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e5.78 (-1.64, 13.20)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e3.78\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.1265\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; \u0026nbsp; Employed full or part time\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e10.75 (3.26, 18.24)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e3.82\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.0049\u0026nbsp;\u003c/span\u003e\u003cspan lang=\"EN\"\u003e#\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; \u0026nbsp; Disabled\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e3.89 (-3.87, 11.64)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e3.95\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.3259\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eNumber of comorbidities\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.96 (-2.09, 0.16)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.57\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.0921\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003ePain intensity\u0026nbsp;\u003c/span\u003e\u003cspan lang=\"EN\"\u003e\u0026para;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.37 (-0.57, -0.17)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.102\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.001**\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 710px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003eEducation\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;High School diploma/GED or less\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-0.52 (-4.15, 3.11)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.85\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.7805\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;Some college, Vocational/skilled trade, or Associates degree\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-2.25 (-5.44, 0.94)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.62\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.1672\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;Bachelors, masters, or professional degree\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003ereference\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e-\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003ePrior back surgery\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.09 (-2.10, 4.28)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.63\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.5033\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 390px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003ePrescription opioid use in last year (any)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 173px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.63 (-2.50, 3.76)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e1.60\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e0.6915\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 710px;\"\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e*To conduct multiple regression, the FSC method was used to impute missing values in both continuous and CLASS variables in a dataset with an arbitrary missing pattern, producing n=3,350 complete cases after 10 imputations\u003c/span\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026dagger; Model 1\u0026nbsp;\u003c/span\u003e\u003cspan lang=\"EN\"\u003eR\u003csup\u003e2\u0026nbsp;\u003c/sup\u003e0.159 \u0026ndash; 0.183\u003c/span\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026Dagger;\u0026nbsp;\u003c/span\u003e\u003cspan lang=\"EN\"\u003eModel 2 R\u003csup\u003e2\u0026nbsp;\u003c/sup\u003e0.447 \u0026ndash; 0.471\u003c/span\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026sect;\u0026nbsp;\u003c/span\u003e\u003cspan lang=\"EN\"\u003eModel 3 R\u003csup\u003e2\u0026nbsp;\u003c/sup\u003e0.171 \u0026ndash; 0.183\u003c/span\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e‖\u0026nbsp;\u003c/span\u003e\u003cspan lang=\"EN\"\u003eModel 4 R\u003csup\u003e2\u0026nbsp;\u003c/sup\u003e0.268 \u0026ndash; 0.289\u003c/span\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e\u0026para;\u0026nbsp;\u003c/span\u003e\u003cspan lang=\"EN\"\u003ePain intensity was measured by PROMIS Pain Intensity Short Form-3 T-score.\u003c/span\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e#\u003c/span\u003e\u003cspan lang=\"EN\"\u003ep-value \u0026lt;0.05\u003c/span\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN\"\u003e**p-value \u0026lt;0.001\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"}],"fulltextSource":"","fullText":"","funders":[{"identity":"f4bf33ad-27c1-467b-94be-49e977e4d46a","identifier":"10.13039/100006379","name":"Office of Research and Development","awardNumber":"1IK2CX002646-01A2, RCS 11-222","order_by":0},{"identity":"4ca116df-2e9a-47db-b63b-df192d691974","identifier":"10.13039/100000049","name":"National Institute on Aging","awardNumber":"5P30AG024824-20, 5T32AG062403; 3T32AG062403-03S1","order_by":1},{"identity":"1178c6cf-167e-4362-b11a-525759dfe69d","identifier":"10.13039/100007217","name":"Health Services Research and Development","awardNumber":"Pain Opioid CORE Rapid Start Grant","order_by":2}],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Veterans Health Administration","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Veterans, aging, chronic low back pain, nociplastic pain","lastPublishedDoi":"10.21203/rs.3.rs-8376244/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8376244/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eChronic low back pain (CLBP) affects nearly one million Veterans and is a leading cause of disability. Nociplastic pain, characterized by altered central nervous system processing, widespread pain and sleep disturbance, may negatively impact treatment response in this population, yet remains underrecognized.\u003c/p\u003e\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eDetermine the prevalence and association of nociplastic features with function among aging Veterans with CLBP.\u003c/p\u003e\u003ch2\u003eDesign:\u003c/h2\u003e \u003cp\u003eCross-sectional survey of Veterans aged 50\u0026ndash;89 years with CLBP identified through VA administrative data. A stratified random sampling design oversampled women and Black/African-American veterans.\u003c/p\u003e\u003ch2\u003eParticipants:\u003c/h2\u003e \u003cp\u003eOf 800 invited, 361 responded (45.1% response rate); after excluding those without CLBP, 342 participants were included (mean age 69.2 years, 19.2% women, 17.8% Black/African-American).\u003c/p\u003e\u003ch2\u003eMain Measures:\u003c/h2\u003e \u003cp\u003eNociplastic features were assessed using the Fibromyalgia Survey Questionnaire to calculate a fibromyalgia severity score. Function was assessed via the Veterans RAND 12-Item Health Survey (VR-12) Physical (PCS) and Mental Component Summary (MCS) scores. Regression models adjusted for sociodemographics, comorbidities, opioid use, pain intensity, and surgical history.\u003c/p\u003e\u003ch2\u003eKey Results:\u003c/h2\u003e \u003cp\u003eNociplastic characteristics were highly prevalent (fibromyalgia severity score mean 11.3, SD 5.9). Overall, 36% screened positive for fibromyalgia via American College of Rheumatology criteria, however, over half of respondents aged 50\u0026ndash;64 years met criteria. Widespread pain was common; on average, pain was experienced in six discrete locations. Physical function was severely impaired (mean VR-12 PCS 30.2, nearly 2 SD below population norms); psychological function was moderately impaired (mean MCS 45). Higher fibromyalgia severity scores independently associated with poorer physical function (β= -0.30 per point increase, 95% CI -0.49, -0.12; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0014) and psychological function (β= -0.64, 95% CI -0.93, -0.35; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) after adjustment. Gender, BMI, comorbidities, and back surgery were also associated with poorer function.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eNociplastic features are highly prevalent in aging Veterans with CLBP and demonstrate a dose-response relationship with impaired functioning. Recognition may guide more effective, mechanism-based treatment approaches and reduce harm.\u003c/p\u003e","manuscriptTitle":"Association of Nociplastic Pain Features with Function in Aging Veterans with Chronic Low Back Pain","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-17 07:24:21","doi":"10.21203/rs.3.rs-8376244/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"abfdf2f1-a907-47c7-9254-e4540f2c8646","owner":[],"postedDate":"December 17th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":59748407,"name":"Geriatrics \u0026 Gerontology"},{"id":59748408,"name":"Anesthesiology \u0026 Pain Medicine"}],"tags":[],"updatedAt":"2025-12-17T07:24:27+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-17 07:24:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8376244","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8376244","identity":"rs-8376244","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}