Race, neighborhood disadvantage, and survival of Medicare beneficiaries after aortic valve replacement and concomitant coronary artery bypass grafting

Background: Race, neighborhood disadvantage, and the interaction between these 2 social determinants of health remain poorly understood with regards to survival after aortic valve replacement with concomitant coronary artery bypass grafting (AVR+CABG). Methods: Weighted Kaplan-Meier survival analyses and Cox proportional hazards modeling were used to evaluate the association between race, neighborhood disadvantage, and long-term survival in 205,408 Medicare beneficiaries undergoing AVR+CABG from 1999 to 2015. Neighborhood disadvantage was measured using the Area Deprivation Index, a broadly validated ranking of socioeconomic contextual disadvantage. Results; Self-identified race was 93.9% White and 3.2% Black. Residents of the most disadvantaged quintile of neighborhoods included 12.6% of all White beneficiaries and 40.0% of all Black beneficiaries. Black beneficiaries and residents of the most disadvantaged quintile of neighborhoods had more comorbidities compared with White beneficiaries and residents of the least disadvantaged quintile of neighborhoods, respectively. Increasing neighborhood disadvantage linearly increased the hazard for mortality for Medicare beneficiaries of White but not Black race. Residents of the most and least disadvantaged neighborhood quintiles had weighted median overall survival of 93.0 and 82.1 months, respectively, a significant difference (P < .001 by Cox test for equality of survival curves). Black and White beneficiaries had weighted median overall survival of 93.4 and 90.6 months, respectively, a nonsignificant difference (P = .29 by Cox test for equality of survival curves). A statistically significant interaction between race and neighborhood disadvantage was noted (likelihood ratio test P = .0215) and had implications on whether Black race was associated with survival. Conclusions: Increasing neighborhood disadvantage was linearly associated with worse survival after combined AVR+CABG in White but not Black Medicare beneficiaries; race, however, was not independently associated with postoperative survival.