Persistent Racial Disparities in Morbidity Following Major Elective Operations

Abstract

Introduction: Despite considerable national attention, racial disparities in surgical outcomes persist. We sought to consider whether race-based inequities in outcomes following major elective surgery have improved in the contemporary era. Methods: All adult hospitalization records for elective coronary artery bypass grafting, abdominal aortic aneurysm repair, colectomy, and hip replacement were tabulated from the 2016-2020 National Inpatient Sample. Patients were stratified by Black or White race. To consider the evolution in outcomes, we included an interaction term between race and year. We designated centers in the top quartile of annual procedural volume as high-volume hospitals (HVH). Results: Of ∼2,838,485 patients, 245,405 (8.6%) were of Black race. Following risk-adjustment, Black race was linked with similar odds of in-hospital mortality, but increased likelihood of major complications (Adjusted Odds Ratio [AOR] 1.41, 95%Confidence Interval [CI] 1.36-1.47). From 2016-2020, overall risk-adjusted rates of major complications declined (patients of White race: 9.2% to 8.4%; patients of Black race 11.8% to 10.8%, both P < .001). Yet, the delta in risk of adverse outcomes between patients of White and Black race did not significantly change. Of the cohort, 158,060 (8.4%) were treated at HVH. Following adjustment, Black race remained associated with greater odds of morbidity (AOR 1.37, CI 1.23-1.52; Ref:White). The race-based difference in risk of complications at HVH did not significantly change from 2016 to 2020. Conclusion: While overall rates of complications following major elective procedures declined from 2016 to 2020, patients of Black race faced persistently greater risk of adverse outcomes. Novel interventions are needed to address persistent racial disparities and ensure acceptable outcomes for all patients.

Keywords

racial disparities elective surgery surgical outcomes HCUP

Introduction

For decades, a growing body of work has documented pervasive racial disparities in health care outcomes across the US.^1–3 Indeed, Black race has been linked with significantly increased all-cause morbidity following numerous low- and high-risk surgical procedures, relative to non-Hispanic Whites.^4,5 While the underlying mechanisms continue to be elucidated, prior work has attributed these inequities to greater disease severity at presentation,² increased likelihood of emergent surgery, and care at lower quality^6,7 or lower volume hospitals.⁸ Yet, a landmark report from the Institute of Medicine⁹ and others⁶ have suggested racial disparities in outcomes remain, even after adjusting for such patient and hospital factors.

Irrespective of cause, a myriad of efforts has been implemented at the regional and national levels to address race-based inequities in surgical outcomes, including the 2015 Patient Protection and Affordable Care Act (ACA), with discrepant results. While Mehtsun et al¹⁰ noted a narrowing gap in postoperative mortality between Black and White Medicare patients, the study period occurred before implementation of ACA and Medicaid expansion. Others have more recently evaluated individual operations or limited cohorts, and reported continued racial inequities in outcomes.^11,12 Ultimately, mitigating race-based inequities in outcomes remains a national imperative. A comprehensive understanding of how such disparities have evolved since the ACA is lacking but could guide future interventions and policy initiatives.

In this work, we evaluated the contemporary association of race with morbidity following major elective operations. We secondarily assessed the evolution of morbidity rates over the last five years. Lastly, we considered whether care at high-volume centers would mitigate any noted disparities in outcomes. We hypothesized that Black race would remain associated with inferior outcomes, without significant improvement over the study period. We further hypothesized that care at high-volume hospitals would reduce, but not eliminate, inequities in surgical outcomes.

Methods

Data Source and Study Cohort

All adult (≥18 years) hospitalization records entailing elective CABG, AAA repair, colectomy, and hip replacement were tabulated from the 2016-2020 National Inpatient Sample (NIS) using previously-validated International Classification of Diseases, Tenth Revision codes. These procedures were specifically selected as they are commonly performed across institutions in the US., and encapsulate a broad, nationally-representative cohort that would permit analysis of overall trends.¹⁰ The NIS is the largest all-payer database reporting hospital discharge data and accounts for >97% of the U.S. population.¹³

Variable Definitions and Study Outcomes

Patients were stratified by White or Black race, as reported in the NIS. Records entailing other race/ethnicity (13.6%) or missing key data were excluded (<1%, Figure 1).

Figure 1.

CONSORT Diagram of Survey-Weighted Estimates Of an estimated 2,838,485 records tabulated from the 2016-2020 National Inpatient Sample and included for analysis, 244,405 (8.6%) were of Black race. All estimates represent survey-weighted methodology.

The Health care Cost and Utilization Project data dictionary was used to detail patient and hospital characteristics.¹³ The van Walraven modification of the Elixhauser comorbidity index was applied to quantify the patient burden of chronic illness.¹⁴ Relevant comorbidities and perioperative complications were ascertained using previously published ICD-10 codes.¹⁵

Center-specific annual caseloads were computed for each operation. Institutions in the top quartile of annual volume were designated as high-volume hospitals (HVH) for the specific operative category. Specifically, centers were considered HVH for AAA repair if annual volume >10, for CABG if annual volume >279, for colectomy if annual volume >105, and for hip replacement if annual volume >200 cases.

The primary outcome of this study was in-hospital mortality. We secondarily evaluated the incidence of perioperative complications, duration of hospitalization, and discharge to extended care facilities.

Statistical Analysis

Variables are reported as medians with interquartile range (IQR) if continuous, or as group proportions (%), otherwise. The significance of intergroup differences was ascertained using the Mann-Whitney U, adjusted Wald, or Pearson’s chi-square test, as appropriate.

We subsequently fit multivariable regression models to consider the independent association of race with key study outcomes. Model covariates were automatically selected using elastic net regularization, which utilizes a penalized least-squares methodology to minimize model overfitting and increase out-of-sample generalizability.¹⁶ Model covariates included patient age, sex, Elixhauser comorbidity index and relevant comorbidities, income quartile, rural/urban location, operation, hospital volume, hospital teaching status, hospital region, and year of admission. An interaction term was introduced between race and year of hospitalization. We then estimated the risk adjusted absolute point estimates for major morbidity. To consider temporal changes in adjusted risk of morbidity, we computed the delta in risk between cohorts for each year, over the study period.

The receiver operating characteristic was used to evaluate model goodness of fit. Logistic and linear model outputs are reported as adjusted odds ratios (AOR) and beta-coefficients (β), respectively, both with 95% confidence intervals (CI). Statistical significance was set at α = .05. All statistical analyses were performed using Stata 16.1 (StataCorp, College Station, TX). Due to the deidentified nature of the NIS, this study was deemed exempt from full review by the Institutional Review Board of the University of California, Los Angeles.

Results

Cohort Characteristics

Of an estimated 2,838,485 patients undergoing elective operations, 244,405 (8.6%) were of Black race. Patients of Black race more frequently underwent colectomy, but less often AAA repair, CABG, and hip replacement. On average, patients of Black race were younger, more commonly female, and of a higher Elixhauser comorbidity index distribution, compared to those of White race. Further, patients of Black race were more frequently of lowest income quartile, insured by Medicaid, and treated at metropolitan teaching institutions in the South (Table 1).

Table 1.

Demographic, Clinical, and Hospital Characteristics.

	White Race (n = 2,594,080)	Black Race (n = 244,405)	P-value
Age (years [IQR])	67 [59-74]	62 [53-69]	<.001
Female (%)	50.3	53.5	<.001
Elixhauser Comorbidity Index (median [IQR])	2 [1-3]	2 [1-4]	<.001
Operation (%)			<.001
AAA repair	3.8	3.6
CABG	14.2	10.5
Colectomy	24.3	29.8
Hip replacement	61.1	59.3
Income percentile (%)			<.001
76th-100th	27.1	13.2
51st-75th	27.4	18.3
26th-50th	26.4	22.4
0-25th	19.1	46.1
Insurance coverage (%)			<.001
Private	37.1	36.8
Medicare	55.3	43.9
Medicaid	4.5	13.7
Other payer	3.1	5.6
Comorbidities (%)
Cardiac arrhythmias	17.0	11.1	<.001
Cancer	10.9	14.5	<.001
Coagulopathy	5.3	4.1	<.001
Congestive heart failure	7.7	9.1	<.001
Coronary artery disease	19.3	14.5	<.001
Cerebrovascular disorders	2.8	3.0	.006
Chronic pulmonary disease	15.5	16.8	<.001
Diabetes	18.4	26.4	<.001
Hypertension	60.2	70.6	<.001
Liver disease	1.9	2.4	<.001
Obesity	21.1	27.2	<.001
Peripheral vascular disease	5.0	4.3	<.001
Hospital region (%)			<.001
Northeast	20.4	16.0
Midwest	26.3	19.1
South	35.1	56.7
West	18.3	8.3
Hospital teaching status (%)			<.001
Metropolitan teaching	70.2	79.7
Metropolitan non-teaching	22.3	16.1
Rural	7.5	4.3

Reported as proportions (%) unless otherwise noted. Statistical significance was set at α = .05. IQR, Inter-Quartile Range.

Postoperative Outcomes

Following risk adjustment, and with those of White race as reference, patients of Black race experienced similar odds of in-hospital mortality, but greater likelihood of any perioperative complication. Specifically, Black race was linked with increased odds of cardiac, respiratory, and renal sequelae, as well as increased likelihood of blood transfusion (Table 2).

Table 2.

Unadjusted and Adjusted Outcomes Following Major Elective Procedures, Stratified by Race.

	Unadjusted			Adjusted
	White Race	Black Race	P	Black Race	95% CI	P
Clinical Outcomes
In-hospital mortality	0.5	0.5	.03	1.09	.94-1.26	.25
Any complication	8.6	11.0	<.001	1.41	1.36-1.47	<.001
Cardiac complications	1.1	1.1	.28	1.33	1.19-1.47	<.001
Infectious complications	1.2	1.6	<.001	1.07	.98-1.16	.14
Respiratory complications	2.4	2.6	.002	1.12	1.05-1.20	.001
Blood transfusion	5.4	7.3	<.001	1.53	1.45-1.61	<.001
Thromboembolism	0.2	0.4	<.001	1.05	.87-1.27	.59
Stroke	0.2	0.2	.71	1.19	.95-1.50	.14
Acute kidney injury	4.9	6.9	<.001	1.64	1.57-1.72	<.001
Non-home discharge	13.5	16.2	<.001	1.59	1.54-1.65	<.001

Outcomes reported as proportions or as Adjusted Odds Ratio (AOR) with 95% confidence intervals (95% CI). Reference: White race. Regression models were adjusted for patient age, sex, Elixhauser comorbidity index and relevant comorbidities, income quartile, rural/urban location, operation, hospital volume, hospital teaching status, hospital region, and year of admission. An interaction term was introduced between race and year of hospitalization. IQR, Inter-Quartile Range; USD, United States Dollar.

This persisted across each operation considered for analysis, such that the cohort of patients of Black race faced increased relative risk of complications following AAA repair (34.2 vs 27.2%), CABG (21.3 vs 16.4%), colectomy (17.3 vs 13.1%), and hip replacement (4.4 vs 3.2%) (Figure 2).

Figure 2.

Adjusted Risk of Complications, Stratified by Race. Following adjustment, patients of Black race demonstrated greater adjusted risk of major perioperative complications following elective AAA repair (34.2 vs 27.2%, P < .001), CABG (21.3 vs 16.4%, P < .001), colectomy (17.3 vs 13.1%, P < .001), and hip replacement (4.4 vs 3.2%, P < .001). * indicates statistical significance, P < .001. CABG, Coronary artery bypass grafting; AAA, abdominal aortic aneurysm.

Temporal Trends

Evaluating elective operations from 2016 through 2020, risk-adjusted rates of major perioperative complications decreased for both those of White race (9.2% in 2016 to 8.4% in 2020, P < .001) and Black race (11.8% in 2016 to 10.8% in 2020, P < .001). However, no significant difference in the delta in adjusted risk of complications between patients of White and Black race was observed (2016 vs 2020: −Δ0.3%, CI −1.2 to .7%) (Figure 3).

Figure 3.

Temporal Trends in Adjusted Risk of Perioperative Complications. Following risk adjustment, Black race remained associated with greater likelihood of complications following elective operations, relative to White race. No significant change in the difference in adjusted risk of postoperative complications between patients of White and Black race was observed over the study period.

Impact of Elective Care at High Volume Hospitals

Among all patients, 1,883,691 (66.4%) were treated at HVH, of whom 158,060 (8.4%) were of Black race. On average, patients of Black race were younger, more frequently female, and more often treated in the South. The cohort of Black patients more frequently underwent AAA repair and colectomy, but less often CABG and hip replacement (Supplemental Table S1).

Following risk adjustment, and with White race as reference, Black race remained linked with similar in-hospital mortality, but greater likelihood of any major perioperative complication. Namely, Black race was associated with increased odds of stroke and acute kidney injury, as well as need for blood transfusion and non-home discharge (Supplemental Table S2). Upon stratification by operation type, patients of Black race remained associated with greater adjusted risk of perioperative complications following CABG, colectomy, and hip replacement, but not AAA repair (Figure 4). Further, the difference in risk of complications between patients of White and Black race did not meaningfully change over the study period (2016 vs 2020: Δ0.3%, CI -2.7 to 3.2%) (Figure 5).

Figure 4.

Risk-Adjusted Complication Rates at High-Volume Hospitals, Stratified by Operation Following adjustment, and considering only those electively admitted at HVH, patients of Black race continued to face increased risk of major perioperative complications following CABG (17.8 vs 13.6%), colectomy (16.0 vs 12.1%), and hip replacement (3.4 vs 2.5%), but similar likelihood following AAA repair (35.2 vs 28.3%). * indicates statistical significance, P < .001. HVH, High-Volume Hospital, CABG, Coronary artery bypass grafting; AAA, abdominal aortic aneurysm.

Figure 5.

Temporal Trends in Adjusted Risk of Perioperative Complications at High-Volume Hospitals. After risk adjustment, and only considering patients treated at high-volume hospitals, Black race remained associated with greater likelihood of complications following elective operations, relative to White race. No significant change in the difference in adjusted risk of complications following such procedures between patients of White and Black race was observed over the study period.

Discussion

In the present national analysis, we analyzed race-based disparities in morbidity following major elective operations, and made several important observations. Patients of Black race demonstrated significantly greater odds of postoperative complications. Notably, overall risk-adjusted rates decreased over time, but the disparity between Black and White patients persisted, such that patients of Black race continued to face greater morbidity risk over the study period. While care at high-volume centers was linked with lower morbidity, race-based differences in complications remained. With implications towards national policy and practice, these findings merit further discussion.

We noted significant racial disparities in morbidity rates following elective AAA repair, CABG, colectomy, and hip replacement. Indeed, patients of Black race faced greater likelihood of cardiac, respiratory, and renal sequelae following such procedures. These associations held true after controlling for comorbidity burden, as well as income and insurance coverage. Altogether, our findings add to a body of work stretching back two decades reporting racial disparities in surgical outcomes.^1,3–6,9 Expanding on this literature, we identified continued outcomes inequities in the contemporary period.

Prior literature has attributed differences in postoperative complication rates to care at low-volume or low-quality institutions.^7,8 Yet, we found the delta in risk between patients of Black and White race to remain similar regardless of center volume. Our findings, therefore, suggest expanding access to high-volume centers alone will not entirely mitigate race-based inequities. Interestingly, these findings contradict a study by Parson et al,¹⁷ who reported similar outcomes between White and Black patients receiving cancer care at American College of Surgeons National Surgical Quality Improvement Program-participating hospitals. However, we postulate that the selected sample of patients undergoing cancer resection at such institutions may significantly differ from the national cohort of patients captured in this work. Furthermore, while expanding access to high-volume centers remains important, our study also calls for an examination of systemic and social contributors to outcomes inequities. In particular, efforts are needed to uncover and address implicit bias across physicians and hospitals,¹⁸ improve the quality of patient-physician communication,¹⁹ and ensure equitable care delivery, both during and after hospitalization. In both tangible and intangible ways, these factors may shape the quality of care patients receive, and may significantly influence their perioperative outcomes.

Across elective operations, irrespective of care at high-volume centers, race-based disparities in outcomes persisted over time. Importantly, a myriad of policies and programs aimed at addressing inequities in health outcomes have been implemented over the last decade, including the 2014 ACA. While such programs were linked with dramatic expansions of health insurance coverage and overall access to health care, literature has reported insignificant impact on hospitalization outcomes.²⁰ In our study, we found overall morbidity rates declined over time, yet the delta between Black and White patients has remained. Taken together, our findings suggest these programs may have improved care overall, but have been ineffective in addressing racial inequities. Of note, an earlier work by Mehtsun et al¹⁰ reported decreasing racial inequities in postoperative mortality from 2010 to 2014. Our study found comparable mortality, but not morbidity rates between patients of Black and White race. A greater emphasis on postoperative morbidity as a quality metric in future policies and performance incentive programs may contribute to mitigating racial disparities.

The present work has several important limitations. As an administrative database, the NIS relies on ICD coding, which can vary based on local practices. Granular physiologic, laboratory, or radiographic data was unavailable for analysis. Degree of clinical severity or extent of disease burden was not accessible. However, the NIS has been used and validated extensively to analyze surgical outcomes. Lastly, due to the retrospective nature of this work, causal conclusions cannot be made. Despite these limitations, however, we applied robust analytical methods and evaluated a large, nationally-representative cohort, to consider the contemporary state of racial disparities in outcomes following major surgical operations.

In conclusion, we identified persistent disparities in postoperative morbidity among patients of Black and White race undergoing major elective surgery. This gap persisted across the five-year study period, without significant change. Additionally, while care at high-volume centers reduced overall rates of morbidity, racial disparities in outcomes remained. Future work is needed to elucidate the root cause of these inequities. Ultimately, national programs and policies are needed to more effectively mitigate the racial disparities gap beyond the efforts of the ACA.

Supplemental Material

Supplemental Material - Persistent Racial Disparities in Morbidity Following Major Elective Operations

Supplemental Material for Persistent Racial Disparities in Morbidity Following Major Elective Operations by Sara Sakowitz, Syed Shahyan Bakhtiyar, Saad Mallick, Giselle Porter, Konmal Ali, Amulya Vadlakonda, Joanna Curry, and Peyman Benharash in The American Surgeon™.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Supplemental Material

Supplemental material for this article is available online.

References

Lucas

Stukel

Morris

Siewers

Birkmeyer

. Race and surgical mortality in the United States. Ann Surg. 2006;243(2):281-286. doi:10.1097/01.sla.0000197560.92456.32

Morris

Rhoads

Stain

Birkmeyer

. Understanding racial disparities in cancer treatment and outcomes. J Am Coll Surg. 2010;211(1):105. doi:10.1016/j.jamcollsurg.2010.02.051

Esnaola

Hall

Hosokawa

, et al. Race and surgical outcomes: it is not all Black and White. Ann Surg. 2008;248(4):647. doi:10.1097/SLA.0b013e31818a159a

Azin

Hirpara

Doshi

Chesney

Quereshy

Chadi

. Racial disparities in surgery: a Cross-specialty matched comparison between Black and White patients. Ann Surg Open. 2020;1(2):e023. doi:10.1097/AS9.0000000000000023

Ravi

Sood

Schmid

, et al. Racial/ethnic disparities in perioperative outcomes of major procedures. Ann Surg. 2015;262(6):955-964. doi:10.1097/SLA.0000000000001078

Rangrass

Ghaferi

Dimick

. Explaining racial disparities in outcomes after cardiac surgery: the Role of hospital quality. JAMA Surg. 2014;149(3):223-227. doi:10.1001/jamasurg.2013.4041

Dimick

Ruhter

Sarrazin

Birkmeyer

. Black patients more likely than whites to undergo surgery at low-quality hospitals in segregated regions. Health Aff (Millwood). 2013;32(6):1046-1053. doi:10.1377/hlthaff.2011.1365

Haider

Scott

Rehman

, et al. Racial disparities in surgical care and outcomes in the United States: a Comprehensive review of patient, provider and systemic factors. J Am Coll Surg. 2013;216(3):482-492. doi:10.1016/j.jamcollsurg.2012.11.014

Unequal Treatment . Confronting Racial and Ethnic Disparities in Health Care. Washington, D.C.: National Academies Press; 2003. 10.17226/12875

10.

Mehtsun

Figueroa

Zheng

Orav

Jha

. Racial disparities in surgical mortality: the Gap appears to have narrowed. Health Aff (Millwood). 2017;36(6):1057-1064. doi:10.1377/hlthaff.2017.0061

11.

Hernandez-Morgan

Stypula

Fischer

Grogan

Neelankavil

. Impact of the affordable care Act on disparities in access to and outcomes after coronary artery bypass grafting. J Racial Ethn Health Disparities. 2023;10(6):2783-2791. doi:10.1007/s40615-022-01455-8

12.

Burton

Munir

Labastide

Sanchez

Gabriel

. An Update on racial disparities with 30-day outcomes after coronary artery bypass graft under the Affordable Care Act. J Cardiothorac Vasc Anesth. 2019;33(7):1890-1898. doi:10.1053/j.jvca.2018.10.021

13.

Healthcare Cost and Utilization Project . Overview of the national (nationwide) inpatient sample (NIS). https://www.hcup-us.ahrq.gov/nisoverview.jsp

14.

van Walraven

Austin

Jennings

Quan

Forster

. A Modification of the Elixhauser comorbidity measures into a point system for hospital death using administrative data. Med Care. 2009;47(6):626-633.

15.

Madrigal

Mukdad

Han

, et al. Impact of hospital volume on outcomes following head and neck cancer surgery and flap reconstruction. Laryngoscope. 2021;132(7):1381-1387. doi:10.1002/lary.29903

16.

Zou

Hastie

. Regularization and variable selection via the elastic net. J R Stat Soc Ser B Stat Methodol. 2005;67(2):301-320. doi:10.1111/j.1467-9868.2005.00503.x

17.

Parsons

Habermann

Stain

Vickers

Al-Refaie

. What happens to racial and ethnic minorities after cancer surgery at American College of Surgeons National Surgical Quality Improvement Program hospitals? J Am Coll Surg. 2012;214(4):539-547. doi:10.1016/j.jamcollsurg.2011.12.024

18.

Santry

Wren

. The Role of unconscious bias in surgical safety and outcomes. Surg Clin. 2012;92(1):137-151. doi:10.1016/j.suc.2011.11.006

19.

Hisam

Zogg

Chaudhary

, et al. From understanding to action: interventions for surgical disparities. J Surg Res. 2016;200(2):560-578. doi:10.1016/j.jss.2015.09.016

20.

Wadhera

Bhatt

Wang

, et al. Association of state Medicaid expansion with quality of care and outcomes for low-income patients hospitalized with acute myocardial infarction. JAMA Cardiol. 2019;4(2):120-127. doi:10.1001/jamacardio.2018.4577

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.00 MB

0.28 MB