Prevalence of Chronic Overlapping Pain Conditions in Participants With Chronic Low Back Pain Enrolled in a Pragmatic Trial of Mindfulness-Based Stress Reduction.

This cross-sectional study includes analysis of data collected at a single timepoint as part of a multisite pragmatic randomized clinical trial of an online synchronous video-conference group mindfulness program or usual primary care for people with cLBP. Study protocol and recruitment for the Optimizing Pain Treatment in Medical settings Using Mindfulness (OPTIMUM) trial have been published elsewhere.( Greco et al., 2021 ) We implemented the COPC-Screener after the initiation of the OPTIMUM study, therefore not all participants in the larger trial were included. We used psychosocial, demographic, and clinical data collected at the baseline visit of the parent study in the present study, avoiding effects of the intervention. The COPC-Screener was administered at a single time point. The OPTIMUM trial recruited participant cohorts across three US sites, representing patients from Academic medical centers and community health settings in urban, suburban, and rural communities, including people with Medicaid, uninsured, and private insurance. Participating sites were Boston University Medical Center (BUMC), Piedmont Health Services and the integrated healthcare delivery system of the University of North Carolina at Chapel Hill Hospitals (UNC), and the University of Pittsburgh Medical Center (UPMC) from 2020–2023. Both the parent study and the COPC ancillary project were approved by IRBs at each study site (UNC IRB#19–2032). Study participants were 285 students who met the criteria for cLBP in both duration and frequency at enrollment in the OPTIMUM Study. The COPC-Screener was added after the first group of participants had completed the study, limiting the total number of participants eligible to complete the screener. Criteria for inclusion were English-speaking adults ≥ 18 years old, with chronic low back pain, persisting for at least 3-months and resulting in pain on at least half the days in the past 6 months, and a score ≥ 3 on the PEG (Pain, Enjoyment of Life, and General Activity) Scale( Krebs et al., 2009 ) indicating pain was causing interference in daily functioning. Exclusion criteria for participation in OPTIMUM were: practicing mindfulness meditation at least once a week, recent loss of 10 pounds or more, current unexplained fever, current cancer treatment, recent unexplained worsening of pain, back pain caused by injury occurring in the previous three months, pregnancy or planning to become pregnant within the next three months, not a patient at a participating clinic or planning to continue as a patient at the participating clinic for the next twelve months or if a relative or cohabitant was participating in the study. No additional examination of enrollees or confirmation via diagnostic codes was performed to assess an individual’s pain. Specific inclusion for this sub-study was anyone who was enrolled in the parent study (OPTIMUM) that responded to queries to complete the screener. Seven individuals initiated the screener but did not finish, therefore these people were not included in analyses. Chronic Overlapping Pain Condition-Screener (COPC-S) ( Schrepf et al., 2023 ) is self-administered via online survey, and responses were captured using an embedded REDCap ( Schrepf et al., 2022 ) framework. The online survey was administered in week 8 of enrollment in the trial, but participants were able to complete the survey later, if necessary. Prior to implementation, consultation with the study’s community advisory board resulted in a few basic changes to the screener to increase useability. The COPC-S was developed and validated by researchers to screen populations for the presence of symptomatic chronic overlapping pain conditions. Initial validation reported excellent agreement between the COPC-S and criteria administered by a physician. Analysis of data from 30 participants resulted in a kappa score of .813 indicating excellent agreement.( Schrepf et al., 2023 ) All participants completed a Symptom Severity (SS) scale assessing the severity of fatigue, cognitive symptoms, unrefreshing sleep over the past week (with ranking options of no problem, slight of mild problems due to the symptom, moderate problems, or severe problems related to the symptom) and specific yes/no questions about depression, and headache in the previous 6 months. Survey responses trigger an algorithm that identifies whether participants are likely to have any of the 10 recognized COPCs. The screener uses a body map to select areas of pain or tenderness over the past 30 days. The responses trigger subsequent questions regarding specific diagnostic criteria. The body map included 19 unique anatomical sites that were numeric and color-coded for self-reporting pain. These body map responses were summed to create the Widespread Pain Index ranging from 0–19. A classification of fibromyalgia requires that pain be present in at least 4 of 5 regions (to avoid misclassification of regional pain syndromes).( Wolfe et al., 2016 ) Areas of endorsed pain did not necessarily qualify as a COPC. For example, the screener uses the NIH Task Force on chronic low back pain criteria for identifying someone as having cLBP; per the screener was dependent on the following: 1) self-reported pain in areas associated with the lower back, 2) duration of pain that has persisted at least 3 months, and 3) frequency of pain on at least half of the days in the past 6 months( Deyo et al., 2014 ). Pain impact was assessed at baseline using the 3-item PEG, an instrument designed to assess pain intensity (P), interference with enjoyment of life (E), and interference with general activity (G) during the past week.( Krebs et al., 2009 ) The PEG is scored by calculating a mean score from 0–10 where 0 represents no pain and no interference while a score of 10 indicates the highest level of pain intensity and interference reported as “completely interferes”. The generally accepted meaningful clinically important difference (MCID) for the PEG is 1 point.( Krebs et al., 2009 ) The short form pain catastrophizing scale (6-item) was used to assess individual levels of pain catastrophizing at baseline. These six items asked the participant to report how often they experience feelings of distress such as “It’s awful and I feel that it overwhelms me” and “I become afraid that the pain will get worse” when they are experiencing pain.( McWilliams et al., 2015 ) Answers are reported using a Likert scale ranging from 0 representing “not at all” to 4 representing “all the time”. A summary score ranging from 0–24 is calculated based on responses to all six items with higher scores representing more frequent endorsement of catastrophizing responses to experiences of pain. In longer versions of the scale, a score representing the 75 th percentile has been identified as a clinically significant cut point.( Sullivan et al., 1995 ) In our sample, the score at the 75 th percentile was 17. We created a cut point at the 75 th percentile and compared the proportion of people with cLBP with high pain catastrophizing to the proportion of people with cLBP+ COPCs who scored high in pain catastrophizing. Sleep disturbance, fatigue, depressive symptoms, anxiety, pain interference, ability to participate in social roles, and physical functioning were assessed using the Patient-Reported Outcomes Measurement Information System 29-Profile (PROMIS-29)( Dewitt et al., 2018 ), a widely used 29-item questionnaire that has been validated across studies of health-related quality of life and chronic pain.( Terkawi et al., 2023 ) PROMIS assessments are converted to a T-score metric with a mean of 50 for the overall population and a standard deviation of 10. In general, T-scores are interpreted as a higher score on a negative health outcome (sleep disturbance, fatigue, depressive symptoms, anxiety, and pain interference) indicates more symptoms and poorer functioning while the physical functioning and ability to participate in social roles scores are reverse scored with higher scores signifying higher levels of functioning and participation, respectively. Bookmarking or thresholds of meaningful change in PROMIS measures have been suggested for pain interference and fatigue scores in rheumatoid arthritis patients( Bingham et al., 2021 ) and clinically meaningful cut-points in adult patients with rheumatic diseases( Nagaraja et al., 2018 ) have suggested a meaningful difference for both clinicians and patients range from 5 to 7 points. Difference in PROMIS measures of half a standard deviation from the standardized T-score population mean of 50 and standard deviation of 10 have been suggested as meaningful shifts in people with fibromyalgia.( Wohlfahrt et al., 2019 ) We used cut-points of scoring PROMIS measures to delineate normal scores from individuals with mild, moderate, and severe impairment using general cut points for mild (0.5 to 1.0 SD) moderate (1.0–2.0 SD), severe difficulty (2.0+ SD) ( Supplemental Table S1 ). PROMIS scores measuring sleep disturbance, fatigue, depressive symptoms, anxiety, and pain interference all follow the same scoring with higher scores indicating lower functioning while Physical functioning scores and social roles scores are scored such that lower scores indicate worse physical and social role functioning.( Health Measures 2024 ) The PROMIS measures are designed to measure distinct domains. However, it is important to note that those domains likely interact and overlap with one another. We examined the correlation between the PROMIS domain scores. Participant demographic information was collected by self-report at the time of enrollment. Sex assigned at birth, age, race, ethnicity, marital status, duration of pain, employment status, annual household income, and level of educational attainment were assessed. Study site was defined as the research site (Boston Medical Center, University of North Carolina, or University of Pittsburgh). The exposure of interest was one or more COPCs (not including cLBP) compared to cLBP only. The outcomes of interest were measures of physical and psychological functioning, including self-reported pain intensity, pain interference, and pain-related measures. Missing data was assessed and reported in descriptive statistics. Participants with missing data were excluded from bivariable and multivariable analysis (n=7). In this exploratory study, we performed Student’s t -tests to compare the mean values of continuous variables between the two groups. PROMIS measures of pain interference, anxiety, depressive symptoms, fatigue, sleep disturbance, physical functioning and ability to participate in social roles were normally distributed. Means were calculated for the total sample, t-tests were used to compare means between the cLBP only group and the group of participants with cLBP and an additional COPC, and multivariable analysis was performed to examine the difference in PROMIS scores between the two groups after adjusting for age, sex, and study site. Multivariable analysis was repeated separately with the addition of any pain medication (as a binary variable) to the adjustment set. Categorical variables were examined for frequency and association with exposure variables (categories of fatigue, cognitive functioning and unrefreshing sleep) using chi-squared tests and Fishers exact tests as appropriate. From the screener, we report the body map regions identified as painful, symptoms and severity endorsed on the symptom severity (SS) scale, and the prevalence and number of COPCs identified. Linear regression was used to determine the difference in PROMIS-29 measures and pain impact (PEG) measures, comparing those with cLBP only to those with cLBP and at least one additional COPC. Linear models were adjusted for potential confounders of study site (UNC, BMC, PIT), age (continuous), and sex assigned at birth (male or female). Multicollinearity was assessed using variance inflation factors (VIF) with values of 5 or larger as a cut point for problematic multicollinearity. Separate descriptive analyses were performed using the count of COPCs as a categorical variable using the following cut-points: 0 additional COPCs, 1 COPC, 2 COPCs, and 3 or more COPCs. This analysis aimed to examine the difference in each measure associated with the number of COPCs, as opposed to using the COPC binary variable described above. Means and medians for PROMIS-29 measures were calculated for each of the four categories to determine if an increase in symptoms and decrease in functioning was observed as the number of COPCs increased. We examined potential effect measure modification due to race by performing the multivariable linear regression within subgroups of race (Black or White). Additional racial groups (Asian, American Indian or Alaskan Native, or those who described themselves as multiracial) were not included in the analysis stratified by race due to small sample size. We also stratified the regression analysis by sex (male or female). To address the sex-specific nature of two conditions (endometriosis and VVS), we created a binary variable representing those with cLBP compared with those with cLBP and another COPC not including endometriosis or VVS. All analyses were performed using SAS version 9.4 (Cary, North Carolina). Instead of a priori null hypothesis testing, we rely on published guidance ( McShane et al., 2019 ) and report results including measures of the effect size and 95% confidence intervals around estimates. We report p-values as continuous measures for mean differences and beta coefficients reported from linear regression as well as the 95% confidence intervals around the beta coefficients and R 2 .

Two hundred and eight-five participants completed the COPC-Screener, with a mean age of 52.2 years (SD=15.3). Participants were predominately female sex assigned at birth (n=198, 69.5%). Half of the sample self-identified as White (n=143, 50.2%), while 119 participants (41.8%) of the sample identified as Black ( Table 1 ). The number of participants who identified as Asian, American Indian/Alaskan Native, identified more than one race, or did not report their race accounted for less than 25 participants. Most participants reported their ethnicity as not Hispanic or Latino (n=252, 89.4%). One hundred and fifty-three participants reported that they were not employed (53.9%) and educational attainment ranged from 25 people (8.8%) who did not complete high school to 55 participants (19.4%) who reported the completion of doctoral or post graduate education ( Table 1 ). Nearly everyone in the study (95.4%, n=272) reported experiencing pain outside the upper and lower back region, with the average number of pain locations reported on the body map was 4.4 (SD=3.4). The most frequently reported pain sites outside of the upper and lower back region were the right hip (n=103, 36.1%) and the lower right leg (n=84, 29.5%). Participants also reported pain in the right shoulder (n=76, 26.7%) and the neck (n=73, 25.6%) ( Supplemental Table S2 ). In this sample of 285 people seeking treatment for cLBP, nearly half (n=129, 45.3%) were identified as having an additional COPC per the screener. Irritable bowel syndrome was the most common COPC, impacting 56 (19.9%) of people ( Table 2 ). The next most common COPC was ME/CFS with 54 (18.9%) people identified using the COPC screener. Fibromyalgia was identified in 42 individuals (14.7%), tension type or migraine headache was identified in 32 (11.4%), UCPPS was found in 21 (7.4%) of the sample, 13 people met criteria for TMD (4.6%). Out of 198 women, endometriosis was identified in 24 (12.1%), vulvodynia impacted 12 (6.1%). When cLBP was excluded from the total count of COPCs, 45.3% (n=129) of the sample had at least one COPC while 23.9% (n=68) of the sample had 2 or more COPCs. The symptom severity scale identified a high prevalence of fatigue and unrefreshing sleep, with a greater frequency of severe fatigue reported in people with additional COPCs compared to people with cLBP alone (20.1% vs 1.9%). Fatigue was common in this sample with most (236, 82.8%) reporting fatigue in the prior 7 days, and 10.2% reporting severe fatigue; 174 (61.0%) people reported cognitive symptoms on the screener with 4.9% of the sample reporting severe cognitive symptoms; and 87.4% (n=249) reported unrefreshing sleep, while 15.4% reported unrefreshing sleep symptoms as severe ( Table 3 ). There was no difference in the duration of sleep reported in the two groups (cLBP only vs. cLBP and COPCs). Over the past 6 months, 50.9% of the sample endorsed experiencing depression and 54.7% reported they experienced headaches in the past 6 months. On the 3-item PEG, the average pain score for the past week for the entire sample was 6.0 out of 10 on the numeric pain rating scale (SD=2.2). People with cLBP and at least one additional COPC reported higher numeric pain ratings during the past week compared to those with only cLBP, 6.5 (SD=2.1) vs 5.7 (SD=2.3), respectively, and higher pain interference scores, 6.5 (SD=2.2) vs 5.4 (SD=2.4), respectively. There was no difference in the self-reported duration of pain, with both groups reporting more than 10 years of low back pain. Eighty-six percent of the sample (n=245) reported taking any medication for pain, with 129 (52.7% of the sample) reporting taking prescription medication for pain and 25 (10.2% of the sample) reporting taking opioids for pain ( Table 3 ). There were no strong differences in reports of taking medication for pain, including prescription medication and opioids when comparing people with cLBP only to those with cLBP and at least one additional COPC. People with cLBP and an additional COPC had higher pain catastrophizing scores compared to people with cLBP only (mean in cLBP only=10.7, SD=5.9, mean in cLBP and COPC=13.5, SD=5.9, MD=2.8, 95%CI 1.5, 4.2). When applying the low/high cut point for catastrophizing based on the 75 th percentile of the PCS (score=17), we found 35.2% (n=45) of people with additional COPCs were in the high catastrophizing group compared with 17.3% (n=27) of people in the cLBP only group. All mean comparisons of PROMIS measures reflected differences between the cLBP only and cLBP and additional COPCs group ( Table 3 ). These differences demonstrated that people with COPCs reported experiencing worse health outcomes in all areas except sleep disturbance. In the cLBP only group, the mean score on the sleep disturbance measure was 57.7 (SD=4.3), while the mean score in the cLBP and additional COPCs group was 56.1 (SD=4.5), indicating mild sleep disturbance on average in both groups. The largest difference between the two groups was observed on the PROMIS measure of fatigue with people with cLBP and additional COPCs scoring on average 7.6 points higher compared to those with cLBP only (mean with cLBP only=52.9, SD=9.3, mean in cLBP and COPC=60.5, SD=8.2). Lower scores indicating reduced physical functioning (MD= −2.9 (95% CI −4.3, −1.5)), and ability to participate in social roles (MD= −4.2 (95% CI −6.2, −2.2)) were observed in the group with cLBP and additional COPCs compared to the group with only cLBP, indicating that having additional COPCs was associated with a decreased ability to perform physical functions and social roles. Both groups scored below the population mean t-score of 50 ( Table 3 ). Results of the bivariable analysis resulted in higher scores on PROMIS measures assessing pain interference when comparing the two groups (mean with cLBP only=60.3, SD=7.7, mean cLBP and COPC=64.0, SD=6.0, MD= 3.6 95% CI 2.0, 5.2). Depressive symptoms, anxiety and fatigue scores in people with COPCs were within the moderate range, while mean scores in the cLBP only group were in the mild range. Higher scores on measures of anxiety, depressive symptoms, and fatigue were consistent in people with an additional COPC compared to people with cLBP only after adjustment for study site, sex, and age ( Table 4 ). The largest difference between people with cLBP and COPCs compared to people with cLBP only was the fatigue score, where people with cLBP and COPCs had a higher mean fatigue score by 7.31 (95% CI 5.19, 9.43) points compared to people with cLBP alone after adjustment. After adjustment, results indicated poorer health in people with cLBP and COPCs compared to those with cLBP only. This was true in all PROMIS measures except sleep disturbance and consistent when adjustment for any pain medication was included ( Supplemental Table S3 ). The most frequently observed overlap was cLBP and IBS (n=51, 17.9%), followed by cLBP and ME/CFS, (n= 48,16.8% of the sample). Out of 54 people who were identified with ME/CFS, 21 (38.8%) also had IBS and 21 had ME/CFS and fibromyalgia (38.8%). Eighteen of 42 (42.8%) participants with fibromyalgia met criteria for IBS ( Figure 1 ). Race was not associated with having additional COPCs (unadjusted OR comparing Black participants to White participants was 1.38 (95% CI 0.84, 2.26)). The role of race was assessed by performing the linear regression models restricted to participant groups by self-defined by race (White or Black). Although confidence intervals overlapped, point estimates for Black individuals indicated worse health (higher sleep disturbance, higher fatigue, more depression and more anxiety) on PROMIS measures when comparing Black people with an additional COPC to White people with an additional COPC. Also, point estimates for Black individuals indicated less impairment in social roles and physical functioning when compared to estimates from the sample restricted to only White individuals indicating that although people from a racially minoritized group may have reported more impairment and more clinical symptoms, Black individuals reported higher levels of functioning and less pain interference ( Figure 2 ). Unlike race, sex was statistically associated with having additional COPCs. Females had 1.83 times the odds of having an additional COPC compared to males (95% CI 1.08, 3.01). However, this could be due in part to 2 pain conditions only classified in females (endometriosis and VVS). Upon removing the two sex-specific conditions from the count and thus the binary variable of cLBP vs cLBP with an additional COPC (which changed the classification of 13 females), the OR reduced, and the confidence interval widened (OR=1.40, 95% 0.83, 2.37). When we examined each condition and sex, we observed an association between sex and fibromyalgia as well as sex and IBS, but we do not see a relationship between sex and cLBP, ME/CFS, BPS, migraine, TMD, or tension-type headache. We repeated the linear regression models restricted to only females and then repeated the models using only male participants. While the direction of the coefficients did not change, all the PROMIS measures and PEG items had wider confidence intervals with the effect estimates when the sample was restricted to only men. For women, the effect sizes were greater for every outcome comparing those without COPCs to those with COPCs. For example, the change in social roles in women comparing those with an additional COPC to those with only cLBP, the mean difference was −6.18 (95% −8.59, −3.79), after adjusting for study site and age ( Supplemental Table S4 ). Adjustment for age and study site resulted in an OR=1.73 (95% CI 1.02, 2.95). When we repeated the multivariable analysis of the PROMIS measures stratified by sex and adjusted for study site and age, we observed females with additional COPCs experienced more negative health outcomes on PROMIS measures compared to those with LBP only. Males with additional COPCs consistently had scores that indicated less fatigue, depression, anxiety, pain interference ( Figure 3 ). Males (with COPCs) had almost no difference in their score on the measure assessing the ability to fulfill social roles but reported slightly more physical function impairment compared to females. When we used the categorization of number of COPCs not including cLBP as opposed to the two groups of cLBP only and cLBP and another COPC, we observed a monotonic relationship of increasing fatigue, decreased ability to participate in social roles and decreased physical functioning as the number of pain conditions increased. We observed consistently worse scores in those with one, two or three or more COPCs compared to those without COPCs, but this difference does not appear to reflect a linear or exponential relationship between outcomes and the number of COPCs assessed with the PROMIS-29 measures assessing pain interference, sleep, anxiety, or depression ( Supplementary Figure 1 ).

Results found high prevalence of COPCs (45.3%) in people seeking treatment for cLBP associated with high symptom burden demonstrated by negative self-reported health, increased pain interference, increased anxiety, depressive symptoms, and fatigue. Our findings show that people who experience COPCs live with increased symptom burden and reduced quality of life. The increase in indicators of reduced quality of life in those with additional COPCs in all measures except for sleep disturbance, provides a multidimensional examination of the areas in which patients with COPCs may differ from those with cLBP alone. This finding is consistent with other studies that people with COPCs have more symptoms and poorer functioning.( Crane et al., 2017 ; Fillingim et al., 2020 ; Henningsen et al., 2022 ; Terkawi et al., 2023 ) Our approach differs from prior studies that relied on reports of body pain or diagnoses from medical records by using a validated screener to assess chronic overlapping pain conditions.( Schrepf et al., 2023 ) The COPC screener and the OPTIMUM study baseline assessments demonstrate that COPCs are a major cause for concern in patients presenting with cLBP. In a larger study (n=8783) of patients with cLBP, 94.5% of patients were identified as having cLBP and COPCs compared to those with only localized pain. The authors used PROMIS measures and reported mean differences (MD) very similar to our findings. Specifically, the PROMIS fatigue score MD comparing cLBP to cLBP and COPCs was 7.0 points in the reported finding (MD=7.3 (95% CI 5.2, 9.4), MD for physical function of −4.0 whereas we found a MD of −3.2 (95% CI −4.6, −1.8), pain interference MD was 3.4 compared to the MD we observed of 3.7 (95% CI 2.1, 5.4)( Terkawi et al., 2023 ). Although it is important to note that the previous study defined COPCs as two or more painful regions on a standardized body map, as opposed to use of a detailed screener based on consensus diagnostic criteria. The finding that nearly half of the participants met the criteria for at least one additional COPC has ramifications for interventions treating localized pain conditions without assessment of widespread pain. Qualitative research reporting the experiences of women with COPCs has emphasized the disenfranchisement, silencing, and gendered experience in women with COPCs that lead to physician mistrust and deterioration of relationships with treatment providers.( Hintz 2023 ) This study emphasizes what has been found in other chronic pain samples is also true in people with cLBP. We also characterize the symptoms reported in those with cLBP, and an additional pain condition compared to those with cLBP only. In a study restricted to 5 COPCs, researchers found within each primary COPC (self-identified by the participant), pain intensity, pain interference, and the proportion of participants with high-impact pain increased with each additional COPC up to 4 or more COPCs.( Ohrbach et al., 2020 ) In the same population, researchers also reported that two-thirds of cLBP cases had one or more COPCs, with cLBP cases having 2.5 times the odds of having IBS and 20.1 times the odds of having fibromyalgia.( Slade et al., 2020 ) One study found 48% of cLBP patients have fibromyalgia with those with cLBP and FM experiencing more anxiety, depression, add pain catastrophizing compared to those with cLBP alone( Aoyagi et al., 2019 ). In an assessment of people with ME/CFS, researchers found 33% of the sample also had a medical history of chronic low back pain. ( Fall et al., 2024 )However, it is important to note that most people with cLBP reported pain in other areas and the fluctuation of pain and health symptoms may be reflective of a spectrum of symptom severity rather than discrete groups as used in our study and others. Central sensitization is proposed as one mechanism uniting these conditions (although evidence is not conclusive in humans), whereby the central nervous system “amplifies” pain perceived in the peripheral nervous system as a result of biological, environmental, and social processes.( Schirle et al., 2023 ) Neurological research using functional magnetic resonance imaging has suggested variations in white matter microstructure( Huang et al., 2016 ), increased gray matter volume and connectivity in the sensorimotor and insular cortices of the brain comparing pain-free individuals with patients with fibromyalgia, painful bladder syndrome, irritable bowel syndrome, and temporomandibular disorder.( Kutch et al., 2017 ) Other mechanisms, such as genetics, have been identified utilizing twin studies( Gasperi et al., 2017 ) and genome-wide approaches have found differences between single-site and multi-site pain.( Khoury et al., 2022 ) Mechanistic approaches to COPCs have suggested that peripheral inflammation or mechanical damage in peripheral tissue could cause nociplastic pain.( Petzke et al., 2003 ) These findings suggest COPCs share the same pathophysiological mechanism which amplifies signaling in the central nervous system( Fitzcharles et al., 2021 ), otherwise known as central sensitization( Williams 2018 ) and support the conclusion that COPCs represent a single syndrome. This study benefitted from a racially diverse sample collected from multiple study sites representing urban, rural, and a mix of suburban and rural settings. However, due to the nature of the parent study, individuals may not be representative of people with cLBP, but instead generalizable to patients in primary care settings who are willing to enroll in a 12-month study of mindfulness for cLBP. Frequently, generalizability is an issue in clinical research of chronic pain patients, as samples are often recruited from specialty clinics and clinical trials. Because our study enrolled participants from primary care, we believe the results are more generalizable to people with cLBP, but we cannot comment on the sample representativeness education status, race, and ethnicity of the larger community. The screener may not be sensitive to identifying cases but is specific in avoiding false positives. The overall kappa statistic of agreement for the electronic screener and physician criteria was high (0.813) while the kappa statistic for cLBP was 0.780 which nearly matches the percent of this sample of people with cLBP who were identified by the screener as having cLBP.( Schrepf et al., 2023 ) The screener identified cLBP pain in 77% of participants, although all participants met the criteria for cLBP (pain location, duration, and frequency) at the time of enrollment in the OPTIMUM trial. The difference in classification may reflect the ability of the screener to identify cases. Separate analysis of the 65 participants who did not meet criteria for cLBP per the screener did not identify patterns of when the screener was administered relative to study enrollment or study participant characteristics (age, sex, study site). Discrepancies could be attributed to improvement in the condition due to the study intervention, fluctuations in symptoms, issues of remembering pain, or difficulty reporting symptoms using the screener. Additionally, the initial validation of the COPC-screener was performed in a sample of 30 participants, about whom we do not have information about age, gender, or race. Further validation of the scale in a diverse population is warranted. The aim of the screener is to identify commonly coexistent conditions within individuals not to diagnose, but to assess the burden of pain in individuals and may identify those who need treatment; however, it is not clear if the screener is able to create an accurate picture of the prevalence of symptomatic COPCs in the population. This discrepancy could be explained in several ways related to criteria and is not as pertinent as the number of people who were identified with cLBP per the screener. One reason for this concern is the screener would likely miss people whose conditions are well-controlled or well-treated. For example, 156 people (54.7% of the sample) reported problems with headaches in the past 6 months on single-item questions, while the screener identified 28 (9.8%) people as meeting the criteria for migraine headache and 5 people (1.8%) as meeting the criteria for tension type headache. Classifications differ by condition and the rigor of classifications differ as well. For example, the TMD screener includes only self-report items and requires no physical exam while endometriosis requires surgery for diagnosis. The screener questions depend on the body map responses to trigger individual question modules. If a person did not report pain in the jaw on the body map, then they did not trigger the 6-item TMD screener. Because the body map is programmed in the electronic screener to require participants to identify where on the map they have had pain and then scroll down to check the corresponding box to record their experience, this suggests that the results could be different compared to a body map where individuals could click to report pain without the added step of translating where they have had pain on the body map to a separate item response. This added step could lead to an undercounting of COPCs and not an overcounting, reinforcing the conclusion that our estimates represent the lowest number of people with each condition. The same is true for someone who is receiving care and managing their symptoms, who would not be identified as having a COPC per the screener. Instead of pain reported solely on a body map, the COPC screener utilizes rigorous criteria based on frequency, intensity, duration, and for some conditions, physician verification to identify people with active need for treatment. Directionality is a concern when interpreting findings from a single time point about a single measurement. Future studies should examine risk factors for incident COPCs as our cross-sectional approach does not allow for inference regarding a trajectory from cLBP to cLBP with COPCs. A cohort study of 258 patients with abdominal pain found those with widespread pain had more anger, anxiety, and pain interference.( Hah et al., 2022 ) A national EHR database study followed individuals for up to 3 years and found pre-existing diagnosed COPCs predicted the development of long COVID based on ICD-9 and ICD-10 codes, reporting risk ratios from 1.20 for cognitive symptoms (95% CI 1.19, 1.22) to 2.16 for headache (95% CI 2.14, 2.19).( Bergmans et al., 2024 ) Other limits of this study are the potential for bias from residual confounding due to unmeasured variables and the fact that the study was not designed to be statistically powered to detect a specific effect size defined a priori . However, the descriptive aim of this study effectively addressed an assessment of the burden and prevalence of additional chronic pain conditions in people with cLBP.

In 2015, the Chronic Pain Research Alliance released their analysis and policy recommendations emphasizing the need for evidence-based treatments (noting that there were no FDA-approved therapies indicated for more than one COPC) and the “urgent need and tremendous opportunity to advance a comprehensive, rigorous and coordinated research and development effort for COPCs”.( Veasley et al., 2015 ) In this study of chronic low back pain patients, we found 45.3% of participants met the criteria for an additional COPC. Prevalence of irritable bowel syndrome (19.6%), myalgia encephalomyelitis/chronic fatigue syndrome (18.9%), and fibromyalgia (14.7%) were higher than expected ( Kaplan and Ng 2017 ; Valdez et al., 2018 ; Wolfe et al., 1995 ). Our findings suggest that the COPC-screener is a useful tool for identifying untreated pain, but further external validation is needed. As treatment of these conditions is often unsatisfactory and the domain of specialty clinics, based on this finding we encourage clinicians to query their patients about other co-occurring painful or fatiguing conditions. Given the financial, symptomatic, and frustrating burden of COPCs, it is important that researchers explore these conditions in more detail and seek treatments which address symptoms that patients report as the most detrimental to everyday functioning.

In 2010, the Chronic Pain Research Alliance issued a report on the prevalence of 6 of the 10 recognized chronic overlapping pain conditions (COPCs), impacting 50 million people and healthcare cost of $80 billion USD annually in direct and indirect health care expenses.( Veasley et al., 2015 ) The National Institutes of Health acknowledges COPCs as “a set of disorders that co-aggregate and include, but are not limited to, chronic low back pain (cLBP), migraine and chronic tension-type headache, fibromyalgia, irritable bowel syndrome (IBS), myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), temporomandibular disorders (TMD), urological chronic pelvic pain syndrome/painful bladder syndrome, endometriosis and vulvodynia”.( Veasley et al., 2015 ) People with COPCs experience worse mental and physical health( Zheng et al., 2024 ), including more depression and anxiety( Hah et al., 2022 ), and have greater healthcare needs.( Falasinnu et al., 2022 ) The estimated prevalence of chronic severe back pain (defined as pain most days or every day and the amount of back pain reported as “a lot”) in the general population is 8.2%, with 75% of people with chronic severe back pain reporting some difficulty with mobility, social participation, self-care, or work participation. ( Feldman and Nahin 2022 ) The prevalence of COPCs in people with back pain is unknown, as are the overlap between COPCs while this information is relevant for assessment and treatment of cLBP. Research has relied on electronic health records (EHR) or study samples from specialty clinics. Research with cLBP patients has reported on the prevalence of COPCs using two sources: EHR ( Zheng et al., 2024 ) or self-reported pain on a body map.( Terkawi et al., 2023 ) In a cohort of 241 patients receiving care at a LBP-specialty clinic, EHR data showed 21.6% of people experienced at least one documented COPC in addition to cLBP. The most common COPCs in this population were migraine (11.2%), IBS (4.1%) and fibromyalgia (2.9%).( Zheng et al., 2024 ) We sought to determine the prevalence of COPCs in a sample of people with cLBP. Our aim was to compare the physical and psychological functioning in those with cLBP only in contrast to individuals with cLBP and at least one additional COPC. In contrast to previous research approaches using diagnosis codes or pain reported on a body map, we administered a validated self-report instrument ( Schrepf et al., 2023 ) in a sample of primary care patients. Recruitment at three study sites where individuals with cLBP were enrolled in a randomized controlled trial of mindfulness for cLBP.