Regional variation in racial disparities among patients with peripheral artery disease.

OBJECTIVE: Prior studies identified significant racial disparities as well as regional variation in outcomes of patients with peripheral artery disease (PAD). We aimed to determine whether regional variation contributes to these racial disparities. METHODS: We identified all white or black patients who underwent infrainguinal revascularization or amputation in 15 deidentified regions of the Vascular Quality Initiative between 2003 and 2017. We excluded three regions with <100 procedures. We used multivariable linear regression, allowing clustering at the hospital level to calculate the marginal effects of race and region on adjusted 30-day mortality, major adverse limb events (MALEs), and amputation. We compared long-term outcomes between black and white patients within each region and within patients of each race treated in different regions using multivariable Cox regression. RESULTS: We identified 90,418 patients, 15,527 (17%) of whom were black. Patients underwent 31,263 bypasses, 52,462 endovascular interventions, and 6693 amputations. Black patients were younger and less likely to smoke, to have coronary artery disease, or to have chronic obstructive pulmonary disease, but they were more likely to have diabetes, limb-threatening ischemia, dialysis dependence, and hypertension and to be self-insured or on Medicaid (all P < .05). Adjusted 30-day mortality ranged from 1.2% to 2.1% across regions for white patients and 0% to 3.0% for black patients; adjusted 30-day MALE varied from 4.0% to 8.3% for white patients and 2.4% to 8.1% for black patients; and adjusted 30-day amputation rates varied from 0.3% to 1.2% for white patients and 0% to 2.1% for black patients. Black patients experienced significantly different (both higher and lower) adjusted rates of 30-day mortality and amputation than white patients did in several regions (P < .05) but not MALEs. In addition, within each racial group, we found significant variation in the adjusted rates of all outcomes between regions (all P < .01). In adjusted analyses, compared with white patients, black patients experienced consistently lower long-term mortality (hazard ratio [HR], 0.80; 95% confidence interval [CI], 0.73-0.88; P < .001) and higher rates of MALEs (HR, 1.15; 95% CI, 1.06-1.25; P < .001) and amputation (HR, 1.33; 95% CI, 1.18-1.51; P < .001), with no statistically significant variation across the regions. However, rates of all long-term outcomes varied within both racial groups across regions. CONCLUSIONS: Significant racial disparities exist in outcomes after lower extremity procedures in patients with PAD, with regional variation contributing to perioperative but not long-term outcome disparities. Underperforming regions should use these data to generate quality improvement projects, as understanding the etiology of these disparities is critical to improving the care of all patients with PAD.