Background

Various studies have demonstrated racial disparities in perioperative care and outcomes. The authors hypothesize that among lower extremity total joint arthroplasty patients, evidence-based perioperative practice utilization increased over time among all racial groups, and that standardized evidence-based perioperative practice care protocols resulted in reduction of racial disparities and improved outcomes.

Methods

The study analyzed 3,356,805 lower extremity total joint arthroplasty patients from the Premier Healthcare database (Premier Healthcare Solutions, Inc., USA). The exposure of interest was race (White, Black, Asian, other). Outcomes were evidence-based perioperative practice adherence (eight individual care components; more than 80% of these implemented was defined as “high evidence-based perioperative practice”), any major complication (including acute renal failure, delirium, myocardial infarction, pulmonary embolism, respiratory failure, stroke, or in-hospital mortality), in-hospital mortality, and prolonged length of stay.

Results

Evidence-based perioperative practice adherence rate has increased over time and was associated with reduced complications across all racial groups. However, utilization among Black patients was below that for White patients between 2006 and 2021 (odds ratio, 0.94 [95% CI, 0.93 to 0.95]; 45.50% vs. 47.90% on average). Independent of whether evidence-based perioperative practice components were applied, Black patients exhibited higher odds of major complications (1.61 [95% CI, 1.55 to 1.67] with high evidence-based perioperative practice; 1.43 [95% CI, 1.39 to 1.48] without high evidence-based perioperative practice), mortality (1.70 [95% CI, 1.29 to 2.25] with high evidence-based perioperative practice; 1.29 [95% CI, 1.10 to 1.51] without high evidence-based perioperative practice), and prolonged length of stay (1.45 [95% CI, 1.42 to 1.48] with high evidence-based perioperative practice; 1.38 [95% CI, 1.37 to 1.40] without high evidence-based perioperative practice) compared to White patients.

Conclusions

Evidence-based perioperative practice utilization in lower extremity joint arthroplasty has been increasing during the last decade. However, racial disparities still exist with Black patients consistently having lower odds of evidence-based perioperative practice adherence. Black patients (compared to the White patients) exhibited higher odds of composite major complications, mortality, and prolonged length of stay, independent of evidence-based perioperative practice use, suggesting that evidence-based perioperative practice did not impact racial disparities regarding particularly the Black patients in this surgical cohort.

Editor’s Perspective
What We Already Know about This Topic
  • Racial disparities in postsurgical outcomes have previously been reported

  • A wide variety of evidence-based perioperative practice utilization exists across institutions and healthcare systems, which could potentially account for differences in postsurgical outcomes

What This Article Tells Us That Is New
  • This study investigated outcomes in more than 3 million lower extremity joint surgery patients using the Premier Healthcare database (Premier Healthcare Solutions, Inc., USA) to investigate differences in outcomes among races, and found that evidence-based perioperative practice, although increasingly used, was less likely to be applied in the care of Black than White patients

  • Even when accounting for the lower use of evidence-based perioperative practice, outcomes were worse among Black patients

Racial and ethnicity disparities in care and outcomes have been drawing extensive attention in recent years. Indeed, such disparities in care have been described in various surgical specialties, such as colorectal,1  cardiac,2  and other settings.3  The existence of such disparities has been associated with worse surgical outcomes among racial minority groups.4,5 

One proposed intervention to reduce the risk for disparate care is the establishment of protocolized care approaches such as Enhanced Recovery after Surgery protocols.6  These interdisciplinary, standardized protocols aim at hastening recovery, optimizing patient outcomes, and minimizing complications after surgery. These protocols typically involve preoperative education, optimization of pain management, early mobilization, and various other components as supported by evidence-based perioperative practice.

To date, there is a paucity of data to show how evidence- based perioperative practice has been implemented across patient groups of different racial backgrounds, and specifically if they can improve disparities and thus outcomes among orthopedic patients, such as lower extremity total joint arthroplasty. We hypothesize that among lower extremity total joint arthroplasty patients, evidence-based perioperative practice utilization increased over time among all racial groups, and that such standardized evidence-based perioperative practice care protocols resulted in reduction of racial disparities and improved outcomes.

Study Design, Data Source, and Patient Population

This retrospective cohort study was approved by the institutional review board of the Hospital for Special Surgery (New York, New York; No. 2017-0169). The requirement for written informed consent was waived given the deidentified nature of the data. From the Premier Healthcare claims database (Premier Healthcare Solutions, Inc., USA; 2006 to 2021), we identified patients who underwent elective knee or hip total joint arthroplasty using a standard set of International Classification of Diseases, Ninth and Tenth Revisions codes that have been previously published.7  The Premier Healthcare database is one of the most comprehensive electronic healthcare databases. It is service-level, all-payer claims data, representing about 20 to 25% of all U.S. hospitals. This manuscript adhered to the Strengthening the Reporting of Observational Studies in Epidemiology and Enhancing the Quality and Transparency of Health Research guidelines.

Inclusion and Exclusion Criteria

The study sample included adult patients from January 2006 to December 2021 who were admitted to the hospital for elective total joint arthroplasty surgery (N = 3,449,941). Exclusion criteria were age less than 18 yr (n = 863), unknown sex (N = 59), unknown race (n = 27,561), or outpatient surgery (n = 64,532).

Study Variables

The main “exposure” of interest was race categorized as Asian, Black, White, or Other. “Other” race included any patient who was not categorized as an Asian patient, Black patient, or White patient per Premier Healthcare. Race is patient self-reported, and the information on race is submitted by the hospitals directly to Premier Healthcare as part of electronic health records. Premier Healthcare only validates that the value submitted by the hospital is a valid entry appropriate for race categories. We elected to focus on race in this study due to the fact that race is a well-defined and consistent variable in the Premier Healthcare database. The ethnicity variable was introduced into Premier Healthcare data collection in 2011, which was categorized as Hispanic or non-Hispanic ethnicity. The changes in the way Hispanic race is reported over time are a product of changes mandated by Centers for Medicare & Medicaid Services (Baltimore, Maryland), whereby Hispanic race was discontinued and instead reported as Hispanic ethnicity. Therefore, patients of Hispanic ethnicity could be White patients, Black patients, Asian patients, and so forth. The change of Hispanic race to Hispanic ethnicity makes the analysis on Hispanic patients uninterpretable. Therefore, we excluded Hispanic patients from this analysis. The reporting and discussion of race followed medical journal guidance as described.8 

Outcomes were modeled sequentially; we first assessed the outcome of evidence-based perioperative practice adherence. Evidence-based perioperative practice use was defined by eight components commonly used in such protocols, identified using billing and Current Procedural Terminology codes as previously described9,10  (appendix 1): (1) use of multimodal anesthesia (including peripheral nerve block, nonsteroidal anti-inflammatory drugs, cyclooxygenase-2 inhibitors, paracetamol or acetaminophen, gabapentin or pregabalin, or ketamine) on the day of surgery or postoperative day 1, (2) use of tranexamic acid on the day of surgery or postoperative day 1, (3) use of antiemetics on the day of surgery or postoperative day 1, (4) use of steroids on the day of surgery, (5) physical therapy on the day of surgery or postoperative day 1, (6) avoidance of urinary catheters, (7) avoidance of patient-controlled analgesia, and (8) avoidance of wound drains. Evidence-based perioperative practice use was operationalized as previously described.9–12  The frequencies of utilization of each component of evidence- based perioperative practice exhibited similar patterns across White, Black, and Asian patients (appendix 2).

An evidence-based perioperative practice adherence variable was created by categorizing the number of evidence- based perioperative practice components applied. A binary outcome variable was generated based on whether a patient received more than 80% of evidence-based perioperative practice components. Secondary outcome variables include any major complication defined by International Classification of Diseases, Ninth and Tenth Revisions codes (including acute renal failure, delirium, myocardial infarction, pulmonary embolism, respiratory failure, stroke, in-hospital mortality, and prolonged length of stay [more than 3 days]; appendix 3).

Patient-level variables included age, sex (male, female), insurance type (commercial, Medicaid, Medicare, uninsured, other), and Elixhauser Comorbidity Index (categorized as 0, 1, 2, 3+). Healthcare-level variables included hospital location (urban, rural), hospital size (fewer than 300, 300 to 499, 500 or more beds), hospital teaching status, procedure type (hip/knee total joint arthroplasty), and year of procedure.

Statistical Analysis

The primary model was specified a priori. We did not perform sample size calculation before data access. No minimum clinical difference was defined a priori. This study is motivated to use all data from 2006 to 2021 available in the Premier Healthcare database.

We first assessed (unadjusted) trends in “high evidence- based perioperative practice” use by racial subgroups. Descriptive analysis of all study variables was stratified by race. Categorical variables were presented as counts and percentages, and continuous variables were presented as median and interquartile ranges.

Mixed-effects models were applied to compare associations between race and the use of more than 80% of evidence-based perioperative practice components, i.e., “high evidence-based perioperative practice.” We subsequently modeled the association between race and “high evidence-based perioperative practice” and the outcomes of any major complication, in-hospital mortality, and prolonged length of stay. We next modeled all covariates to estimate effects for each race groups. Finally, we applied an interaction term between race and evidence-based perioperative practice to assess whether the association between evidence-based perioperative practice and outcomes was any different across racial subgroups, i.e., to assess whether evidence-based perioperative practice protocols exerted a stronger effect in the White patient subgroup versus all other racial subgroups (including Asian patients, Black patients, and other patients), assuming higher odds of complications for all other racial subgroups that would require a stronger impact of evidence-based perioperative practice protocols to reduce potential racial disparities in outcomes. Race is a progressive social construct without biologic meaning. However, genetic admixture and its potential interaction with evidence-based perioperative practice could influence the outcome. We therefore conducted this analysis to further challenge our findings. Models were adjusted for all available covariates. A random intercept term that varies at the level of each hospital was included in the model, accounting for the cluster effect of patients within hospitals as they are likely to experience similar care. Odds ratios and 95% CIs were reported. A P value <0.05 was used as the cutoff for statistical significance. Analyses were performed with SAS version 9.4 (SAS Institute, USA).

All these analyses were the primary analysis. In addition, we conducted a secondary sensitivity analysis on the primary and secondary outcomes by sequentially dropping several components of the evidence-based perioperative practice, including use of tranexamic acid on the day of surgery or postoperative day 1, use of steroids on the day of surgery, and avoidance of patient-controlled analgesia. Each sensitivity analysis was executed exactly as described for the main eight-component analysis.

Our study included 3,356,805 lower extremity total joint arthroplasty patients between 2006 to 2021 (table 1). High evidence-based perioperative practice components utilization was associated with decreased odds of composite major complications, mortality, and prolonged length of stay across all racial groups (table 2).

Evidence-based perioperative practice utilization increased across all racial groups over time, with major changes starting around 2012, and plateauing around 2019 (fig. 1). However, the Black patients consistently had lower evidence-based perioperative practice utilization compared to White patients (odds ratio, 0.94; 95% CI, 0.93 to 0.95). Black patients exhibited higher odds of composite major complications, mortality, and prolonged length of stay compared to the White patients after adjusting high evidence- based perioperative practice use and other variables (table 3). Further stratification on evidence-based perioperative practice utilization indicated that high evidence-based perioperative practice utilization did not seem to improve the worse outcomes associated with Black patients (table 4). Similar patterns of differences between Black patients and White patients were also confirmed with our sensitivity analysis (appendix 4).

Asian patients had lower utilization rates than White patients as well (fig. 1); however, this did not reach statistical significance in the adjusted analysis (odds ratio, 1.01; 95% CI, 0.98 to 1.04). There were no differences between the Asian and White patients in regards to all studied outcomes, except for prolonged length of stay. However, such differences were erased after high evidence-based perioperative practice utilization (table 4).

Our study of more than 3 million lower extremity joint arthroplasty patients indicated evidence-based perioperative practice utilization increased during the last decade across all racial groups. However, racial disparities still exist, with Black patients consistently receiving evidence-based perioperative practice less commonly than White patients. The Black patients exhibited higher odds of composite major complications, mortality, and prolonged length of stay compared to White patients, independent of whether they received evidence-based perioperative practice. Sensitivity analysis on the primary and secondary outcomes by sequentially dropping several components of the evidence-based perioperative practice drew the same conclusions.

Our study confirmed that racial disparities in low extremity total joint arthroplasty exist, with Black patients less commonly receiving interventions like evidence-based perioperative practice that might reduce them. Although the difference in implementation significantly improved during the last decade, there is still room to close the gap. Our finding is consistent with existing literature reporting that racial disparities do exist and that Black patients have a higher risk of morbidity and mortality across many surgical specialties. Historically, Black patients experienced worse outcome related to longer length of stay, higher readmission, and higher mortality after colorectal surgery,1,13  cardiac surgery,14  and oncologic surgery,15  among others.

Evidence-based perioperative practice pathways focus on hastening recovery without compromising on surgical outcomes. Their main focus is on reducing stress and organ dysfunction postoperatively by implementing evidence- based standardized care protocols. Evidence-based perioperative practice has been consistently shown to reduce lengths of stay and perioperative complications, while most of the literature is derived from colorectal surgery.12,16,17  Our results also showed that evidence-based perioperative practice adherence after low extremity total joint arthroplasty was associated with significantly lower odds of composite major complications and mortality, and less prolonged length of stay across all Asian, Black, and White patient subgroups.

Racial disparities are attributable to multiple factors, and are associated with variations at the patient, provider, and healthcare system level. Evidence-based perioperative practice pathways are designed to reduce unwanted variations via standardization, and therefore have been proposed as a platform to minimize potential disparities in surgery. Encouragingly, Buchanan reported that racial disparities in perioperative management and outcomes in 606 elective congenital cardiac surgical patients under the Enhanced Recovery after Surgery pathway did not exist.18  Wahl et al. also reported that an Enhanced Recovery after Surgery pathway was effective in eliminating racial disparity in postoperative length of stay after colorectal surgery without increase of complications and mortality.19  Our study showed that evidence-based perioperative practice compliance improved length of stay without increasing complications among Asian patients.

However, this is not the case for Black patients. Our analysis showed that Black patients exhibited worse outcomes compared to the White patients, independent of whether they received evidence-based perioperative practice or not. While the former finding is not new, the latter indicates that more work is needed on effective strategies to reduce racial disparities. Indeed, Singh et al. studied Medicare data for the years 1991 to 2008 and reported persistent racial disparities in joint arthroplasty usage and readmission rates.20  Likewise, Rudisill et al. conducted a systemic review and meta-analysis on racial and ethnic disparities of 63 published studies and concluded that Black patients exhibited higher incidences of mortality, complications, prolonged length of stay, and readmission.5  However, none of these studies focused on strategies to decrease disparities and improve outcomes. Although both Black and White patients exhibited lower odds for composite major complication, mortality, and prolonged length of stay after receiving evidence-based perioperative practice protocols, the more standardized evidence-based perioperative practice model did not reduce all studied complications when comparing Black and White patients. More research is needed to determine the impact of these pathways on specific populations as why Black patients and White patients respond to evidence-based perioperative practice standardized intervention differently. More research is also indicated to identify any barriers to implementation that may disproportionately affect certain racial or ethnic groups.

It is worth noting that while race and ethnicity can play a role in healthcare disparities, the situation is complex and often involves many other factors, including socioeconomic status, access to health care, and so forth. Addressing racial disparities in health care therefore requires a multifaceted approach that takes into account the unique needs and experiences of each population, and it is important to have robust data and research to inform these efforts.

Our study has several limitations. First, this is a retrospective cohort study. Our study is limited by the quality of existing database and by the available details. Socioeconomic and geographic information could not be extracted for further analysis. Second, we defined evidence-based perioperative practice based on our group’s previous publication.10  Evidence-based perioperative practice pathways vary across different institutions at different times, and our approach is unlikely to appreciate these differences. Third, we defined high evidence-based perioperative practice use as above 80% with equal weight on each component. However, the benefits from different components on the outcome are likely unequal. Fourth, the component used in our definition of evidence-based perioperative practice is similar to that used in many Enhanced Recovery after Surgery pathways. Even though our study includes a period of time before many Enhanced Recovery after Surgery pathways were implemented in the United States, our definition of evidence-based perioperative practice includes many of the same categories (e.g., multimodal analgesia, use of antiemetics, avoidance of drains) in many contemporary Enhanced Recovery after Surgery pathways. Last, there have been some changes in the Premier Healthcare dataset regarding how race and ethnicity were recorded during these years. “Asian” was not recorded as a separate race category before 2008, and Hispanic ethnicity was (erroneously) recorded as a race category in the dataset up until 2011, after which a separate ethnicity variable was created. Therefore, Hispanic ethnicity is to some extent represented in our “Other” race category. We do not believe this will significantly affect our main findings as it is likely to represent a bias toward the null (given the inclusion of patients in the “Other” group for which we expect a potential disparity in terms of evidence-based perioperative practice use and outcomes). Future studies are indicated. Furthermore, although Premier Healthcare does not perform additional external validation process on race, the fact that the Premier Healthcare dataset missed only 0.80% (27,561 of 3,449,941 patients) of race information is a positive indication of the quality of data registry from contributing hospitals.

Conclusions

Evidence-based perioperative practice utilization in lower extremity joint arthroplasty has been increasing during the last decade. However, racial disparities still exist, with Black patients consistently receiving lower evidence-based perioperative practice compliance than the White patients. The Black patients exhibited higher odds of composite major complications, mortality, and prolonged length of stay compared to the White patients, independent of whether they were receiving evidence-based perioperative practice or not.

Research Support

Support was provided solely from institutional and/or departmental sources.

Competing Interests

Dr. Memtsoudis has a U.S. patent application for a Multicatheter Infusion System (US-2017-0361063) and is the owner of SGM Consulting, LLC (Rumson, New Jersey). He is a partner in Parvizi Surgical Innovations, LLC (Philadelphia, Pennsylvania), and investor in HATH (New York, New York). None of the aforementioned relations influenced the conduct of the current study. The other authors declare no competing interests.

Analysis plan of racial disparity, https://links.lww.com/ALN/D298

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Appendixes