Racial and ethnic disparities in 3-year outcomes following infrainguinal bypass for chronic limb-threatening ischemia

Objective: Black and Hispanic patients have had higher rates of chronic limb-threatening ischemia (CLTI) and experienced worse perioperative outcomes after lower extremity bypass compared with White patients. The underlying reasons for these disparities have remained unclear, and data on 3-year outcomes are limited. Therefore, we examined the differences in 3-year outcomes after open infrainguinal bypass for CLTI stratified by race/ethnicity and explored the potential factors contributing to these differences. Methods: We identified all CLTI patients who had undergone primary open infrainguinal bypass in the Vascular Quality Initiative registry from 2003 to 2017 with linkage to Medicare claims through 2018 for the 3-year outcomes. Our primary outcomes were the 3-year rates of major amputation, reintervention, and mortality. We also recorded the 30-day major adverse limb events (MALE) defined as major amputation or reintervention. We used Kaplan-Meier estimation methods and mu ltivariable Cox regression analyses to evaluate the outcomes stratified by race/ethnicity and identify contributing factors. Results: Of the 7108 patients with CLTI, 5599 (79%) were non-Hispanic White, 1053 (15%) were Black, 48 (1%) were Asian, and 408 (6%) were Hispanic patients. Compared with White patients, Black patients had higher rates of 3-year major amputation (Black vs White, 32% vs 19%; hazard ratio [HP], 1.9; 95% confidence interval [CI], 1.7-2.2), reintervention (Black vs White, 61% vs 57%; HR,1.2; 95% CI,1.1-1.3), and 30-day MALE (Black vs White, 8.1% vs 4.9%; HR,1.3; 95% CI,1.2-1.4) but lower mortality (Black vs White, 38% vs 42%; HR, 0.9; 95% CI, 0.8-0.99). Hispanic patients also experienced higher rates of amputation (Hispanic vs White, 27% vs 19%; H R, 1.6; 95% CI, 1.3-2.0), reintervention (Hispanic vs White, 70% vs 57%; HR, 1.4; 95% CI,1.2-1.6), and MALE (Hispanic vs White, 8.7% vs 4.9%; H R,1.5; 95% CI,1.3-1.7. However, mortality was similar between the two groups (Hispanic vs White, 38% vs 42%; HR, 0.88; 95% CI, 0.76-1.0). The low number of Asian patients prevented a meaningful assessment of amputation (Asian vs White, 20% vs 19%; HR, 0.93; 95% CI, 0.44-2.0), reintervention (Asian vs White, 55% vs 57%; HR, 0.79; 95% CI, 0.51-1.2), MALE (Asian vs White, 8.5% vs 4.9%; HR, 0.71; 95% CI, 0.46-1.1), or mortality (Asian vs White, 36% vs 42%; HR, 0.83; 95% CI, 0.52 1.3). In the adjusted analyses, the association of Black race and Hispanic ethnicity with amputation and reintervention was explained by differences in the demographic characteristics (ie, age, sex) and baseline comorbidities (ie, tobacco use, diabetes, renal disease). Conclusions: Compared with White patients, Black and Hispanic patients had higher 3-year major amputation and reintervention rates. However, mortality was lower for Black patients than for the White patients and similar between Hispanic and White patients. Disparities in amputation and reintervention were partly attributable to differences in demographic characteristics and the higher prevalence of comorbidities in Black and Hispanic patients with CLTI. Future work is necessary to determine whether interventions to improve access to care and reduce the burden of comorbidities in these populations will confer limb salvage benefits.