Interaction Between Race and Income on Cardiac Outcomes After Percutaneous Coronary Intervention

Background Compared with White Americans, Black Americans have a greater prevalence of cardiac events following percutaneous coronary intervention. We evaluated the association between race and neighborhood income on post-percutaneous coronary intervention cardiac events and assessed whether income modifies the effect of race on this relationship. Methods and Results Consecutive patients (n=23 822) treated with percutaneous coronary intervention from January 1, 2000, to December 31, 2016, were included. All-cause mortality and major adverse cardiac event were assessed at 3 years. Extended 10-year follow-up was performed for those residing locally (n=1285). Neighborhood income was derived using median adjusted annual gross household income reported within the patient's zip code. We compared differences in treatment and outcomes, adjusting for race, income, and their interaction. In total, 3173 (13.3%) patients self-identified as Black Americans, and 20 649 (86.7%) self-identified as White Americans. Black Americans had a worse baseline cardiac risk profile and lower neighborhood income compared with White Americans. Although risk profile improved with increasing income in White Americans, no difference was observed across incomes among Black Americans. Despite similar long-term outpatient cardiology follow-up and medication prescription, risk profiles among Black Americans remained worse. At 3 years, unadjusted all-cause mortality (18.0% versus 15.2%; P<0.001) and major adverse cardiac event (37.3% versus 34.6%; P<0.001) were greater among Black Americans and with lower income (both P<0.001); race, income, and their interaction were not significant predictors in multivariable models. At 10-year follow-up, increasing income was associated with improved outcomes only in White Americans but not Black Americans. In multivariable models for major adverse cardiac event, income (hazard ratio [HR], 0.97 [95% CI, 0.96-0.98]; P=0.005), Black race (HR, 1.77 [95% CI, 1.58-1.96]; P=0.006), and their interaction (HR, 0.98 [95% CI, 0.97-0.99]; P=0.003) were significant predictors. Similar findings were observed for cardiac death. Conclusions Early 3-year post-percutaneous coronary intervention outcomes were driven by worse risk factor profiles in both Black Americans and those with lower neighborhood income. However, late 10-year outcomes showed an independent effect of race and income, with improving outcomes with greater income limited to White Americans. These findings illustrate the importance of developing novel care strategies that address both risk factor modification and social determinants of health to mitigate disparities in cardiac outcomes.