Dramatic Shift Towards Outpatient Total Hip Arthroplasty in 2020 with No Change in Patient Comorbidities

Dramatic Shift Towards Outpatient Total Hip Arthroplasty in 2020 with No Change in Patient Comorbidities | 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 Dramatic Shift Towards Outpatient Total Hip Arthroplasty in 2020 with No Change in Patient Comorbidities Jong Hyun Choi, Xiuyi Alexander Yang, Gerald Andah, Zeynep Seref-Ferlengez, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7963836/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 Centers for Medicare & Medicaid Services removed total hip arthroplasty (THA) from the inpatient-only list on January 1, 2020. The purpose of this study is to assess the changes in arthroplasty coding site-of-care (inpatient versus outpatient), length of stay, and evaluate the comorbidities of patients undergoing outpatient THA following this change. Methods Patients who received THA in the first quarter (Q1) of 2018, 2019, and 2020 were analyzed from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database. Q1 data were selected to minimize the effects of the COVID-19 pandemic. Patient demographics, length of stay (LOS), comorbidities, and inpatient/outpatient coding were compared among 2018, 2019, and 2020 cohorts. Results 9,534, 11,120 and 9,822 THAs were included in Q1 of 2018, 2019, and 2020, respectively. There were small increases in patients age (p < 0.01), bleeding disorder (p = 0.01), and congestive heart failure (p = 0.02) in 2020 compared to 2018 and 2019. The overall rates of chronic obstructive pulmonary disease, hypertension, and diabetes did not change significantly; p > 0.05. Patients admitted as outpatient THA increased from 2.8% in 2018 to 22.5% in 2020; p < 0.01. The mean LOS in 2018, 2019, and 2020 decreased from 2.2, 2.0, to 1.8 days, respectively; p < 0.01. Conclusion There was a significant increase in the volume of outpatient admission in THA as well as the ratio of outpatient to inpatient THAs performed with no significant change in the demographics or comorbidities. total hip arthroplasty hip osteoarthritis outpatient inpatient comorbidities Medicare Figures Figure 1 Figure 2 Introduction Elective total hip arthroplasty (THA) is a procedure predominantly performed as an inpatient procedure in the United States prior to 2020. Advancements in surgical techniques, pain management, and rapid discharge protocols, in combination with an emphasis on value-based care have led to increased interests in outpatient total hip arthroplasty (THA). 1 – 4 The increased popularity of outpatient THA contributed to the removal of THA from the Inpatient Only (IPO) list by the Centers for Medicare & Medicaid Services (CMS) on January 1, 2020. Benefits of outpatient THA include reduced healthcare costs, improved patient satisfaction, and quicker recovery in select patients compared to those undergoing inpatient THA. 5 – 7 Several independent factors associated with increased postoperative complications following outpatient THA have been identified. 6 With its proposed policy change, CMS stated that selection of patients for outpatient THA needs to be tailored to individual patient needs. Good candidates include those with relatively low anesthesia risk and without significant comorbidities who have in-home support for recovery. 8 Many institutions now offer outpatient THA and the decision to offer outpatient THA remains largely at the discretion of the surgeon. It is unclear, however, the impact this policy change has had on actual hospital length of stay and patient admission coding. The purpose of this study is to quantify the changes in inpatient versus outpatient THA coding and to assess the comorbidity profile of patients undergoing outpatient THA following the removal of THA from the IPO list by CMS. Materials and Methods We retrospectively analyzed data from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP), which is a nationally validated, risk-adjusted, outcome-based database that contains 275 preoperative, intraoperative, and postoperative variables collected from 706 participating sites. The ACS NSQIP and participating hospitals are the sources of data and have not verified and are not responsible for the statistical validity of the data analyses or conclusions derived by the authors here. Patients with commercial insurances, Medicaid, or Medicare are included in the database. Data is collected from each site by a trained and certified Surgical Clinical Reviewer and audited by ACS NSQIP for inter-rater reliability and validity. CMS removed THA from the Medicare IPO list with the start of January 2020. In March 2020, COVID-19 was declared a pandemic by the World Health Organization as well as a national emergency in the United States. 9 In April 2020, the American Academy of Orthopaedic Surgeons released guidelines to defer elective procedures to preserve the limited availability of health-care resources. This led to the cancellation of elective procedures, most pronounced in April 2020, when there was a 98% decrease in elective joint cases compared to that month in prior years. 10 Given that the first wave of the COVID-19 pandemic started between March and April 2020, only procedures in the first quarter (Q1) of 2018, 2019, and 2020 were analyzed in our study to decrease confounding variables associated with the pandemic Patients who underwent elective primary THA based on the Current Procedural Terminology code for primary THA (27130) were included in our study with no exclusions. Patient demographics (age, sex), length of stay (LOS), medical comorbidities (severe chronic obstructive pulmonary disease (COPD), diabetes, hypertension, bleeding disorders, congestive heart failure), and inpatient/outpatient status were collected. Outpatient status includes observational and 23-hour stays. 11 Age was divided into two groups, < 65 years and ≥ 65 years, based on Medicare eligibility. Hospital LOS was used as a categorical variable and categorized by 0, 1, 2, or ≥ 3 days. Categorical and continuous variables were compared with the Pearson chi-squared tests and one-way ANOVA. Statistical analysis was performed with IBM SPSS Statistics. Statistical significance was defined as p ≤ 0.05. Results Population Data There were 9,534, 11,120, and 9,822 THA cases input into the NSQIP database in the first quarter (Q1) of 2018, 2019, and 2020 that met our inclusion criteria, respectively (Table 1 ). There was a slight increase in the average age from 65.4 years to 65.8 years to 65.9 years in 2018, 2019, and 2020, respectively; p < 0.01. There was also a slight increase in the percentage of Medicare eligible patients (≥ 65 years) from 2018 to 2020, which was 5,286 (56%), 6,295 (57%), and 5,683 (58%), respectively; p < 0.01. Inpatient THA Q1 volume was 9,270 (97.2%), 10,641 (95.7%), 7,616 (77.5%) cases in 2018, 2019, and 2020, respectively. Outpatient THA Q1 volume was 264 (2.8%), 479 (4.3%), and 2,206 (22.5%) cases in 2018, 2019, and 2020, respectively (p < 0.01) (Fig. 1). When evaluating all patients undergoing THA, there was a small statistically significant difference in the number of patients with bleeding disorders 207 (2.2%), 183 (1.6%), and 205 (2.1%) in 2018, 2019, and 2020, respectively; p = 0.01 (Table 1 ). The number of patients in the registry with congestive heart failure had a small statistically significant increase 30 (0.3%) in 2018, 42 (0.4%) in 2019, 55 (0.6%) in 2020; p = 0.02. The overall rate of COPD, hypertension, and diabetes did not significantly change between 2018 to 2020; p > 0.05. Length of Stay The overall average LOS decreased in Q1 2018, 2019, and 2020 (2.2 vs 2.0 vs 1.8 days, respectively; p = 0.01) (Fig. 2). While the overall quantity of patients coded as “outpatient” increased in Q1 from 2018 to 2020, the proportion of “outpatient” patients who stayed 2 or more midnights stayed similar, with 16.3%, 12.5%, 14.3% from 2018, 2019, and 2020 respectively (p = 0.4) (Table 2 ). The proportion of patients labeled as “inpatient” and stayed 2 or more midnights decreased from 59.9%, 52.5%, to 48.2% from 2018, 2019, and 2020 respectively (p < 0.001) (Table 2 ). Discussion There are many potential benefits to outpatient total joint arthroplasty when performed in the appropriate candidate. 12 , 13 While there has been no consensus on the ideal patient despite efforts to create standardized protocols, it has been established in several studies that healthier patients are better candidates for outpatient joint arthroplasty. 5 , 6 , 13 – 16 Our study found large increases in outpatient THA from 2018 to 2020, 2.8% to 18.2%, with minimal changes in patient comorbidity profiles. While there was an increase towards outpatient from 2018 to 2019, the removal of total hip arthroplasty from the Medicare IPO list likely contributed to the large increase in 2020. 17 Given the timing of the increase, one possibility is that the change could be driven by insurance companies or other payors. A study by Krueger et al. showed that 54% of physicians had to obtain pre-authorization or appeal a denial for an inpatient total joint arthroplasty at least monthly, while 10% said they have undergone an audit for a patient’s inpatient stay. 18 This increase in administrative burden could be one factor shifting patients towards outpatient total hip arthroplasty. A 2023 study by Christensen et al. reported that contribution margins, the difference between net revenue and total costs per case, is far lower in THA patients indicated for inpatient compared to outpatient as insurance reimbursement has decreased faster than cost. 24–25 Yates et al. also outlined an important unintended consequence seen when total knee arthroplasty was removed from the Medicare IPO list, stating that hospitals moved towards outpatient total knee arthroplasty for Medicare to avoid justifying inpatient stays under two nights and risk violating Medicare two-midnight rule. Despite Medicare’s expectation that most TKAs would still be performed in an inpatient setting, 60% of doctors surveyed had been instructed by the hospital to classify fee for service Medicare patients as outpatient unless they stay longer than 2 nights in the hospital. 19 These factors could be linked to the drastic increase in outpatient total hip arthroplasty coding seen the same year that Medicare removed THA from the IPO list. From 2019 to 2020, while the absolute change in outpatient THA coding increased by 18.2%, the absolute change in patients being discharged on Day 0 was 3%. This is consistent with prior literature showing that despite patients being scheduled for outpatient surgery, a smaller percentage of them are being discharged Day 0. 20,21 A study by Greenky et al. showed that independent risk factors for requiring an inpatient admission were general anesthesia, hypertension, BMI over 35, cardiopulmonary disease, diabetes, American society of anesthesiologist score of 4 and age over 75. 5 However, our study shows that in this patient population, diabetes, cardiopulmonary disease, and hypertension were not less prevalent, raising concerns about whether the increased utilization of outpatient THA is patient centric or due to outside factors. Ideally, the increase in outpatient arthroplasty would derive primarily from the coded as “inpatient” pool who only stayed 0–1 midnights. However, our data found that the proportion of “inpatients” staying two or more midnights actually decreased from 2018 to 2020. Additionally, the proportion of “outpatient” patients who stayed under two midnights stayed similar despite the large increase in “outpatient” arthroplasty (Table 2 ). It is clear that the indications for which patients can be appropriately coded as “outpatient” is unclear and requires further investigation. Our study does have some limitations. To adjust for the impact of COVID-19 in 2020, the data was analyzed by the first quarter of each year and thus may not be representative of the entire year. Patients initially coded as outpatient could have their status change, and based on the hospital coding policy may not be represented in the database. This study only analyzes data up to the year of the policy change which may not represent the full impact of the policy. Confounding variables related to the COVID-19 are possible. Additionally, the variables gathered are limited to those available via the database. Notably, surgical centers are not included in the database. These surgical centers are more likely to be predominantly or exclusively outpatient THA which would affect the overall ratio of outpatient to inpatient cases. Due to the lack of information on individual insurance plans, a 65-year-old age cutoff was used to represent Medicare eligibility. Though the ACS NSQIP database represents one of the largest nationwide samples, it does not collect data from every hospital and surgical center in the United States. Conclusion Since removal of THA from the inpatient only list, there has been a dramatic increase in the number of outpatient THA being performed with no significant change in the comorbidity profile of these patients. A point of further investigation will be needed to investigate whether this trend has continued after COVID. Further studies are needed to understand the driving factor for the dramatic shift for outpatient THA to ensure appropriate patient selection and safe patient outcomes. Declarations Funding Statement There was no funding source for this work Author Contribution JHC, XAY, GA were involved with data collection and wrote the main manuscript text, ZSF performed data analysis. All authors reviewed the manuscript References Debbi EM, Mosich GM, Bendich I, Kapadia M, Ast MP, Westrich GH (2022) Same-Day Discharge Total Hip and Knee Arthroplasty: Trends, Complications, and Readmission Rates. J Arthroplasty Mar 37(3):444–448e1. 10.1016/j.arth.2021.11.023 Dorr LD, Thomas DJ, Zhu J, Dastane M, Chao L, Long WT (2010) Outpatient total hip arthroplasty. J Arthroplasty Jun 25(4):501–506. 10.1016/j.arth.2009.06.005 Aynardi M, Post Z, Ong A, Orozco F, Sukin DC (2014) Outpatient surgery as a means of cost reduction in total hip arthroplasty: a case-control study. Hss j Oct 10(3):252–255. 10.1007/s11420-014-9401-0 Berger RA, Jacobs JJ, Meneghini RM, Della Valle C, Paprosky W, Rosenberg AG (2004) Rapid rehabilitation and recovery with minimally invasive total hip arthroplasty. Clin Orthop Relat Res Dec 429239–247. 10.1097/01.blo.0000150127.80647.80 Greenky MR, Wang W, Ponzio DY, Courtney PM (2019) Total Hip Arthroplasty and the Medicare Inpatient-Only List: An Analysis of Complications in Medicare-Aged Patients Undergoing Outpatient Surgery. J Arthroplasty Jun 34(6):1250–1254. 10.1016/j.arth.2019.02.031 Courtney PM, Boniello AJ, Berger RA (2017) Complications Following Outpatient Total Joint Arthroplasty: An Analysis of a National Database. J Arthroplasty May 32(5):1426–1430. 10.1016/j.arth.2016.11.055 Bertin KC (2005) Minimally invasive outpatient total hip arthroplasty: a financial analysis. Clin Orthop Relat Res Jun 435154–163. 10.1097/01.blo.0000157173.22995.cf Medicare Program (2019) Changes to Hospital Outpatient Prospective Payment and Ambulatory Surgical Center Payment Systems and Quality Reporting Programs (Federal Register) 61142–61492 Declaring a National Emergency Concerning the Novel Coronavirus Disease (COVID-19) Outbreak (2020) Heckmann ND, Bouz GJ, Piple AS et al (2022) Elective Inpatient Total Joint Arthroplasty Case Volume in the United States in 2020: Effects of the COVID-19 Pandemic. J Bone Joint Surg Am Jul 6(13):e56. 10.2106/jbjs.21.00833 Rankin KA, Freedman IG, Rubin LE, Grauer JN (2021) Centers for Medicare & Medicaid Services' 2018 Removal of Total Knee Arthroplasty From the Inpatient-only List Led to Broad Changes in Hospital Length of Stays. J Am Acad Orthop Surg Dec 15(24):1061–1067. 10.5435/jaaos-d-20-01228 Bert JM, Hooper J, Moen S (2017) Outpatient Total Joint Arthroplasty. 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J Arthroplasty Aug 33(8):2412–2416. 10.1016/j.arth.2018.03.025 Ziemba-Davis M, Caccavallo P, Meneghini RM (2019) Outpatient Joint Arthroplasty-Patient Selection: Update on the Outpatient Arthroplasty Risk Assessment Score. J Arthroplasty Jul 34(7s):S40–s43. 10.1016/j.arth.2019.01.007 Lynch JC, Yayac M, Krueger CA, Courtney PM (2021) Amount of CMS Reduction in Facility Reimbursement Following Removal of Total Hip Arthroplasty From the Inpatient-Only List Far Exceeds Reduction in Actual Care Cost. J Arthroplasty Jul 36(7):2276–2280. 10.1016/j.arth.2020.08.038 Krueger CA, Kerr JM, Bolognesi MP, Courtney PM, Huddleston JI 3 (2020) The Removal of Total Hip and Total Knee Arthroplasty From the Inpatient-Only List Increases the Administrative Burden of Surgeons and Continues to Cause Confusion. 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J Arthroplasty 36(7):2276–2280 Tables Table 1 Population Data from 2018 to 2020 2018 2019 2020 p-value N = 9,534 N = 11,120 N = 9,822 Sex Female 5,238 (55%) 5,949 (54%) 5,337 (54%) 0.2 Male 4,296 (45%) 5,170 (46%) 4.485 (46%) Age (years) Mean ± SD 65.4 ± 10.9 65.8 ± 10.9 65.9 ± 10.9 < 0.01 65+ 5,286 (56%) 6,295 (57%) 5,683 (58%) < 0.01 Coding “Inpatient” 9,270 (97.2%) 10,641 (95.7%) 7,616 (77.5%) < 0.01 “Outpatient” 264 (2.8%) 479 (4.3%) 2,206 (22.5%) LOS (days) Mean ± SD 2.2 ± 2.6 2.0 ± 2.4 1.8 ± 2.2 < 0.01 0 575 (6%) 901 (8%) 1,058 (11%) 1 3,354 (35%) 4,559 (41%) 4,773 (49%) 2 2,881 (30%) 3,029 (27%) 2,114 (22%) ≥ 3 2,710 (29%) 2,613 (24%) 1,867 (19%) Bleeding Disorder 207 (2.2%) 183 (1.6%) 205 (2.1%) 0.01 CHF 30 (0.3%) 42 (0.4%) 55 (0.6%) 0.02 COPD 367 (4%) 407 (4%) 351 (4%) 0.6 Chronic Steroid Use 376 (4%) 401 (4%) 347 (4%) 0.27 Diabetes 0.6 Non-insulin 911 (10%) 1,038 (9%) 904 (9%) Insulin 255 (3%) 333 (3%) 291 (3%) Hypertension 5,229 (55%) 6,025 (54%) 5,352 (55%) 0.6 ASA Class N = 9,522 N = 11,109 N = 9,820 1-2 5,283 (55.5%) 5,974 (53.8%) 5,194 (52.9%) < 0.01 3-4 4,239 (44.5%) 5,135 (46.2%) 4,626 (47.1%) < 0.01 SD, standard deviation; LOS, length of stay; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; ASA, American Society of Anesthesiologists Table 2 Length of Stay and “Inpatient/Outpatient” Coding LOS (Days) 2018 2019 2020 p Inpatient 0-1 3708 (40.1%) 5041 (47.5%) 3941 (51.8%) <0.001 ≥2 5548 (59.9%) 5582 (52.5%) 3666 (48.2%) Outpatient 0-1 221 (83.7%) 419 (87.5%) 1890 (85.7%) 0.4 ≥2 43 (16.3%) 60 (12.5%) 315 (14.3%) LOS, length of stay Additional Declarations No competing interests reported. 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08:17:56","extension":"html","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":71576,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7963836/v1/58269a46ff5f69987603786f.html"},{"id":96355603,"identity":"e646b470-80af-41fa-829c-f82ebb8c20e0","added_by":"auto","created_at":"2025-11-20 08:17:56","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":39023,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7963836/v1/a9adb4cb7ec0e09fa1c784c7.png"},{"id":96355604,"identity":"f03d944e-12b4-45de-926c-ab5da3887bc9","added_by":"auto","created_at":"2025-11-20 08:17:56","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":21898,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7963836/v1/8909b1a726ea6da7b0864ffd.png"},{"id":98775246,"identity":"b62a9bf7-8a3b-4a1f-8fcf-6d49f1e507b6","added_by":"auto","created_at":"2025-12-22 12:18:59","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":478222,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7963836/v1/3868e48b-feb7-4b66-b850-ac061705040a.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Dramatic Shift Towards Outpatient Total Hip Arthroplasty in 2020 with No Change in Patient Comorbidities","fulltext":[{"header":"Introduction","content":"\u003cp\u003eElective total hip arthroplasty (THA) is a procedure predominantly performed as an inpatient procedure in the United States prior to 2020. Advancements in surgical techniques, pain management, and rapid discharge protocols, in combination with an emphasis on value-based care have led to increased interests in outpatient total hip arthroplasty (THA).\u003csup\u003e\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e The increased popularity of outpatient THA contributed to the removal of THA from the Inpatient Only (IPO) list by the Centers for Medicare \u0026amp; Medicaid Services (CMS) on January 1, 2020.\u003c/p\u003e\u003cp\u003eBenefits of outpatient THA include reduced healthcare costs, improved patient satisfaction, and quicker recovery in select patients compared to those undergoing inpatient THA.\u003csup\u003e\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e Several independent factors associated with increased postoperative complications following outpatient THA have been identified.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e With its proposed policy change, CMS stated that selection of patients for outpatient THA needs to be tailored to individual patient needs. Good candidates include those with relatively low anesthesia risk and without significant comorbidities who have in-home support for recovery.\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eMany institutions now offer outpatient THA and the decision to offer outpatient THA remains largely at the discretion of the surgeon. It is unclear, however, the impact this policy change has had on actual hospital length of stay and patient admission coding. The purpose of this study is to quantify the changes in inpatient versus outpatient THA coding and to assess the comorbidity profile of patients undergoing outpatient THA following the removal of THA from the IPO list by CMS.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e We retrospectively analyzed data from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP), which is a nationally validated, risk-adjusted, outcome-based database that contains 275 preoperative, intraoperative, and postoperative variables collected from 706 participating sites. The ACS NSQIP and participating hospitals are the sources of data and have not verified and are not responsible for the statistical validity of the data analyses or conclusions derived by the authors here. Patients with commercial insurances, Medicaid, or Medicare are included in the database. Data is collected from each site by a trained and certified Surgical Clinical Reviewer and audited by ACS NSQIP for inter-rater reliability and validity.\u003c/p\u003e\u003cp\u003eCMS removed THA from the Medicare IPO list with the start of January 2020. In March 2020, COVID-19 was declared a pandemic by the World Health Organization as well as a national emergency in the United States.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e In April 2020, the American Academy of Orthopaedic Surgeons released guidelines to defer elective procedures to preserve the limited availability of health-care resources. This led to the cancellation of elective procedures, most pronounced in April 2020, when there was a 98% decrease in elective joint cases compared to that month in prior years.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e Given that the first wave of the COVID-19 pandemic started between March and April 2020, only procedures in the first quarter (Q1) of 2018, 2019, and 2020 were analyzed in our study to decrease confounding variables associated with the pandemic\u003c/p\u003e\u003cp\u003ePatients who underwent elective primary THA based on the Current Procedural Terminology code for primary THA (27130) were included in our study with no exclusions. Patient demographics (age, sex), length of stay (LOS), medical comorbidities (severe chronic obstructive pulmonary disease (COPD), diabetes, hypertension, bleeding disorders, congestive heart failure), and inpatient/outpatient status were collected. Outpatient status includes observational and 23-hour stays.\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e Age was divided into two groups, \u0026lt; 65 years and \u0026ge;\u0026thinsp;65 years, based on Medicare eligibility. Hospital LOS was used as a categorical variable and categorized by 0, 1, 2, or \u0026ge;\u0026thinsp;3 days.\u003c/p\u003e\u003cp\u003eCategorical and continuous variables were compared with the Pearson chi-squared tests and one-way ANOVA. Statistical analysis was performed with IBM SPSS Statistics. Statistical significance was defined as p\u0026thinsp;\u0026le;\u0026thinsp;0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003ePopulation Data\u003c/p\u003e\n\u003cp\u003eThere were 9,534, 11,120, and 9,822 THA cases input into the NSQIP database in the first quarter (Q1) of 2018, 2019, and 2020 that met our inclusion criteria, respectively (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). There was a slight increase in the average age from 65.4 years to 65.8 years to 65.9 years in 2018, 2019, and 2020, respectively; p\u0026thinsp;\u0026lt;\u0026thinsp;0.01. There was also a slight increase in the percentage of Medicare eligible patients (\u0026ge;\u0026thinsp;65 years) from 2018 to 2020, which was 5,286 (56%), 6,295 (57%), and 5,683 (58%), respectively; p\u0026thinsp;\u0026lt;\u0026thinsp;0.01. Inpatient THA Q1 volume was 9,270 (97.2%), 10,641 (95.7%), 7,616 (77.5%) cases in 2018, 2019, and 2020, respectively. Outpatient THA Q1 volume was 264 (2.8%), 479 (4.3%), and 2,206 (22.5%) cases in 2018, 2019, and 2020, respectively (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01) (Fig. 1). When evaluating all patients undergoing THA, there was a small statistically significant difference in the number of patients with bleeding disorders 207 (2.2%), 183 (1.6%), and 205 (2.1%) in 2018, 2019, and 2020, respectively; p\u0026thinsp;=\u0026thinsp;0.01 (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). The number of patients in the registry with congestive heart failure had a small statistically significant increase 30 (0.3%) in 2018, 42 (0.4%) in 2019, 55 (0.6%) in 2020; p\u0026thinsp;=\u0026thinsp;0.02. The overall rate of COPD, hypertension, and diabetes did not significantly change between 2018 to 2020; p\u0026thinsp;\u0026gt;\u0026thinsp;0.05.\u003c/p\u003e\n\u003cp\u003eLength of Stay\u003c/p\u003e\n\u003cp\u003eThe overall average LOS decreased in Q1 2018, 2019, and 2020 (2.2 vs 2.0 vs 1.8 days, respectively; p\u0026thinsp;=\u0026thinsp;0.01) (Fig. 2). While the overall quantity of patients coded as \u0026ldquo;outpatient\u0026rdquo; increased in Q1 from 2018 to 2020, the proportion of \u0026ldquo;outpatient\u0026rdquo; patients who stayed 2 or more midnights stayed similar, with 16.3%, 12.5%, 14.3% from 2018, 2019, and 2020 respectively (p\u0026thinsp;=\u0026thinsp;0.4) (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). The proportion of patients labeled as \u0026ldquo;inpatient\u0026rdquo; and stayed 2 or more midnights decreased from 59.9%, 52.5%, to 48.2% from 2018, 2019, and 2020 respectively (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThere are many potential benefits to outpatient total joint arthroplasty when performed in the appropriate candidate.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e While there has been no consensus on the ideal patient despite efforts to create standardized protocols, it has been established in several studies that healthier patients are better candidates for outpatient joint arthroplasty.\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan additionalcitationids=\"CR14 CR15\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e Our study found large increases in outpatient THA from 2018 to 2020, 2.8% to 18.2%, with minimal changes in patient comorbidity profiles.\u003c/p\u003e\u003cp\u003eWhile there was an increase towards outpatient from 2018 to 2019, the removal of total hip arthroplasty from the Medicare IPO list likely contributed to the large increase in 2020.\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e Given the timing of the increase, one possibility is that the change could be driven by insurance companies or other payors. A study by Krueger et al. showed that 54% of physicians had to obtain pre-authorization or appeal a denial for an inpatient total joint arthroplasty at least monthly, while 10% said they have undergone an audit for a patient\u0026rsquo;s inpatient stay.\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e This increase in administrative burden could be one factor shifting patients towards outpatient total hip arthroplasty. A 2023 study by Christensen et al. reported that contribution margins, the difference between net revenue and total costs per case, is far lower in THA patients indicated for inpatient compared to outpatient as insurance reimbursement has decreased faster than cost.\u003csup\u003e24\u0026ndash;25\u003c/sup\u003e Yates et al. also outlined an important unintended consequence seen when total knee arthroplasty was removed from the Medicare IPO list, stating that hospitals moved towards outpatient total knee arthroplasty for Medicare to avoid justifying inpatient stays under two nights and risk violating Medicare two-midnight rule. Despite Medicare\u0026rsquo;s expectation that most TKAs would still be performed in an inpatient setting, 60% of doctors surveyed had been instructed by the hospital to classify fee for service Medicare patients as outpatient unless they stay longer than 2 nights in the hospital.\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e These factors could be linked to the drastic increase in outpatient total hip arthroplasty coding seen the same year that Medicare removed THA from the IPO list.\u003c/p\u003e\u003cp\u003eFrom 2019 to 2020, while the absolute change in outpatient THA coding increased by 18.2%, the absolute change in patients being discharged on Day 0 was 3%. This is consistent with prior literature showing that despite patients being scheduled for outpatient surgery, a smaller percentage of them are being discharged Day 0.\u003csup\u003e20,21\u003c/sup\u003e A study by Greenky et al. showed that independent risk factors for requiring an inpatient admission were general anesthesia, hypertension, BMI over 35, cardiopulmonary disease, diabetes, American society of anesthesiologist score of 4 and age over 75.\u003csup\u003e5\u003c/sup\u003e However, our study shows that in this patient population, diabetes, cardiopulmonary disease, and hypertension were not less prevalent, raising concerns about whether the increased utilization of outpatient THA is patient centric or due to outside factors.\u003c/p\u003e\u003cp\u003eIdeally, the increase in outpatient arthroplasty would derive primarily from the coded as \u0026ldquo;inpatient\u0026rdquo; pool who only stayed 0\u0026ndash;1 midnights. However, our data found that the proportion of \u0026ldquo;inpatients\u0026rdquo; staying two or more midnights actually decreased from 2018 to 2020. Additionally, the proportion of \u0026ldquo;outpatient\u0026rdquo; patients who stayed under two midnights stayed similar despite the large increase in \u0026ldquo;outpatient\u0026rdquo; arthroplasty (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). It is clear that the indications for which patients can be appropriately coded as \u0026ldquo;outpatient\u0026rdquo; is unclear and requires further investigation.\u003c/p\u003e\u003cp\u003eOur study does have some limitations. To adjust for the impact of COVID-19 in 2020, the data was analyzed by the first quarter of each year and thus may not be representative of the entire year. Patients initially coded as outpatient could have their status change, and based on the hospital coding policy may not be represented in the database. This study only analyzes data up to the year of the policy change which may not represent the full impact of the policy. Confounding variables related to the COVID-19 are possible. Additionally, the variables gathered are limited to those available via the database. Notably, surgical centers are not included in the database. These surgical centers are more likely to be predominantly or exclusively outpatient THA which would affect the overall ratio of outpatient to inpatient cases. Due to the lack of information on individual insurance plans, a 65-year-old age cutoff was used to represent Medicare eligibility. Though the ACS NSQIP database represents one of the largest nationwide samples, it does not collect data from every hospital and surgical center in the United States.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eSince removal of THA from the inpatient only list, there has been a dramatic increase in the number of outpatient THA being performed with no significant change in the comorbidity profile of these patients. A point of further investigation will be needed to investigate whether this trend has continued after COVID. Further studies are needed to understand the driving factor for the dramatic shift for outpatient THA to ensure appropriate patient selection and safe patient outcomes.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eFunding Statement\u003c/h2\u003e\u003cp\u003eThere was no funding source for this work\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eJHC, XAY, GA were involved with data collection and wrote the main manuscript text, ZSF performed data analysis. All authors reviewed the manuscript\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eDebbi EM, Mosich GM, Bendich I, Kapadia M, Ast MP, Westrich GH (2022) Same-Day Discharge Total Hip and Knee Arthroplasty: Trends, Complications, and Readmission Rates. 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Curr Rev Musculoskelet Med Dec 10(4):567\u0026ndash;574. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s12178-017-9451-2\u003c/span\u003e\u003cspan address=\"10.1007/s12178-017-9451-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRosinsky PJ, Chen SL, Yelton MJ et al (2020) Outpatient vs. inpatient hip arthroplasty: a matched case-control study on a 90-day complication rate and 2-year patient-reported outcomes. 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J Arthroplasty Aug 32(8):2325\u0026ndash;2331. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.arth.2017.03.004\u003c/span\u003e\u003cspan address=\"10.1016/j.arth.2017.03.004\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKim KY, Feng JE, Anoushiravani AA, Dranoff E, Davidovitch RI, Schwarzkopf R (2018) Rapid Discharge in Total Hip Arthroplasty: Utility of the Outpatient Arthroplasty Risk Assessment Tool in Predicting Same-Day and Next-Day Discharge. 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J Arthroplasty Jul 34(7s):S40\u0026ndash;s43. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.arth.2019.01.007\u003c/span\u003e\u003cspan address=\"10.1016/j.arth.2019.01.007\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLynch JC, Yayac M, Krueger CA, Courtney PM (2021) Amount of CMS Reduction in Facility Reimbursement Following Removal of Total Hip Arthroplasty From the Inpatient-Only List Far Exceeds Reduction in Actual Care Cost. 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J Arthroplasty Dec 33(12):3602\u0026ndash;3606. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.arth.2018.09.043\u003c/span\u003e\u003cspan address=\"10.1016/j.arth.2018.09.043\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eScully RD, Kappa JE, Melvin JS (2020) Outpatient-Same-calendar-day Discharge Hip and Knee Arthroplasty. J Am Acad Orthop Surg Oct 15(20):e900\u0026ndash;e909. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.5435/jaaos-d-19-00778\u003c/span\u003e\u003cspan address=\"10.5435/jaaos-d-19-00778\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eIorio R, Anoushiravani AA, Stronach BM, Barnes CL, Zhang X, Haas DA (2022) The COVID-19 Pandemic and Centers of Medicaid and Medicare Services Regulatory Reform Impact on Total Hip Arthroplasty Metrics. J Arthroplasty Jul 37(7s):S408\u0026ndash;s412. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.arth.2022.02.101\u003c/span\u003e\u003cspan address=\"10.1016/j.arth.2022.02.101\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLynch JC, Yayac M, Krueger CA, Courtney PM (2021) Amount of CMS Reduction in Facility Reimbursement Following Removal of Total Hip Arthroplasty From the Inpatient-Only List Far Exceeds Reduction in Actual Care Cost. J Arthroplasty 36(7):2276\u0026ndash;2280\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1 Population Data from 2018 to 2020\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"661\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e2018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e2019\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e2020\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003eN = 9,534\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003eN = 11,120\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003eN = 9,822\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003eSex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,238 (55%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,949 (54%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,337 (54%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e4,296 (45%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,170 (46%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e4.485 (46%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003eAge (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003eMean \u0026plusmn; SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e65.4 \u0026plusmn; 10.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e65.8 \u0026plusmn; 10.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e65.9 \u0026plusmn; 10.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026lt; 0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003e65+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,286 (56%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e6,295 (57%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,683 (58%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026lt; 0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003eCoding\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003e\u0026ldquo;Inpatient\u0026rdquo;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e9,270 (97.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e10,641 (95.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e7,616 (77.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026lt; 0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003e\u0026ldquo;Outpatient\u0026rdquo;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e264 (2.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e479 (4.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e2,206 (22.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003eLOS (days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003eMean \u0026plusmn; SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e2.2 \u0026plusmn; 2.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e2.0 \u0026plusmn; 2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e1.8 \u0026plusmn; 2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026lt; 0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e575 (6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e901 (8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e1,058 (11%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e3,354 (35%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e4,559 (41%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e4,773 (49%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e2,881 (30%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e3,029 (27%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e2,114 (22%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003e\u0026ge; 3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e2,710 (29%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e2,613 (24%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e1,867 (19%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003eBleeding Disorder\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e207 (2.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e183 (1.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e205 (2.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003eCHF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e30 (0.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e42 (0.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e55 (0.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003eCOPD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e367 (4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e407 (4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e351 (4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003eChronic Steroid Use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e376 (4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e401 (4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e347 (4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003eDiabetes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003eNon-insulin\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e911 (10%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e1,038 (9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e904 (9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003eInsulin\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e255 (3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e333 (3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e291 (3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003eHypertension\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,229 (55%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e6,025 (54%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,352 (55%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003eASA Class\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003eN = 9,522\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003eN = 11,109\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003eN = 9,820\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\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: 24.4713%;\"\u003e\n \u003cp\u003e1-2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,283 (55.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,974 (53.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,194 (52.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026lt; 0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 24.4713%;\"\u003e\n \u003cp\u003e3-4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e4,239 (44.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e5,135 (46.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e4,626 (47.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.8822%;\"\u003e\n \u003cp\u003e\u0026lt; 0.01\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\u003eSD, standard deviation; LOS, length of stay; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; ASA, American Society of Anesthesiologists\u003c/p\u003e\n\u003cp\u003eTable 2 Length of Stay and \u0026ldquo;Inpatient/Outpatient\u0026rdquo; Coding\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 51px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003eLOS\u003c/p\u003e\n \u003cp\u003e(Days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e2018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e2019\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e2020\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003ep\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 51px;\"\u003e\n \u003cp\u003eInpatient\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e0-1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e3708\u003c/p\u003e\n \u003cp\u003e(40.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e5041\u003c/p\u003e\n \u003cp\u003e(47.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e3941\u003c/p\u003e\n \u003cp\u003e(51.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026ge;2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e5548\u003c/p\u003e\n \u003cp\u003e(59.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e5582\u003c/p\u003e\n \u003cp\u003e(52.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e3666\u003c/p\u003e\n \u003cp\u003e(48.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 51px;\"\u003e\n \u003cp\u003eOutpatient\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e0-1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e221\u003c/p\u003e\n \u003cp\u003e(83.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e419\u003c/p\u003e\n \u003cp\u003e(87.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e1890\u003c/p\u003e\n \u003cp\u003e(85.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 85px;\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026ge;2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e43\u003c/p\u003e\n \u003cp\u003e(16.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003cp\u003e(12.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e315\u003c/p\u003e\n \u003cp\u003e(14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eLOS, length of stay\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"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":"total hip arthroplasty, hip osteoarthritis, outpatient, inpatient, comorbidities, Medicare","lastPublishedDoi":"10.21203/rs.3.rs-7963836/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7963836/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eCenters for Medicare \u0026amp; Medicaid Services removed total hip arthroplasty (THA) from the inpatient-only list on January 1, 2020. The purpose of this study is to assess the changes in arthroplasty coding site-of-care (inpatient versus outpatient), length of stay, and evaluate the comorbidities of patients undergoing outpatient THA following this change.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003ePatients who received THA in the first quarter (Q1) of 2018, 2019, and 2020 were analyzed from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database. Q1 data were selected to minimize the effects of the COVID-19 pandemic. Patient demographics, length of stay (LOS), comorbidities, and inpatient/outpatient coding were compared among 2018, 2019, and 2020 cohorts.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003e9,534, 11,120 and 9,822 THAs were included in Q1 of 2018, 2019, and 2020, respectively. There were small increases in patients age (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01), bleeding disorder (p\u0026thinsp;=\u0026thinsp;0.01), and congestive heart failure (p\u0026thinsp;=\u0026thinsp;0.02) in 2020 compared to 2018 and 2019. The overall rates of chronic obstructive pulmonary disease, hypertension, and diabetes did not change significantly; p\u0026thinsp;\u0026gt;\u0026thinsp;0.05. Patients admitted as outpatient THA increased from 2.8% in 2018 to 22.5% in 2020; p\u0026thinsp;\u0026lt;\u0026thinsp;0.01. The mean LOS in 2018, 2019, and 2020 decreased from 2.2, 2.0, to 1.8 days, respectively; p\u0026thinsp;\u0026lt;\u0026thinsp;0.01.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eThere was a significant increase in the volume of outpatient admission in THA as well as the ratio of outpatient to inpatient THAs performed with no significant change in the demographics or comorbidities.\u003c/p\u003e","manuscriptTitle":"Dramatic Shift Towards Outpatient Total Hip Arthroplasty in 2020 with No Change in Patient Comorbidities","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-20 08:17:51","doi":"10.21203/rs.3.rs-7963836/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":"f3fa7166-709a-4767-9742-2629f9ef60fd","owner":[],"postedDate":"November 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-14T22:38:43+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-20 08:17:51","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7963836","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7963836","identity":"rs-7963836","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}