Area Deprivation and Medicare Spending for Coronary Artery Bypass Grafting: Insights From Michigan

Abstract

Background: Prior work has established that high socioeconomic deprivation is associated with worse short- and long-term outcomes for patients undergoing coronary artery bypass grafting (CABG). The relationship between socioeconomic status and 90-day episode spending is poorly understood. In this observational cohort analysis, we evaluated whether socioeconomically disadvantaged patients were associated with higher expenditures during 90-day episodes of care after isolated CABG.

Methods: We linked clinical registry data from 8728 isolated CABG procedures from January 1, 2012, to December 31, 2018, to Medicare fee-for-service claims data. Our primary exposure variable was patients in the top decile of the Area Deprivation Index. Linear regression was used to compare risk-adjusted, price-standardized 90-day episode spending for deprived against nondeprived patients as well as component spending categories: index hospitalization, professional services, post acute care, and readmissions.

Results: A total of 872 patients were categorized as being in the top decile. Mean 90-day episode spending for the 8728 patients in the sample was $55 258 (SD, $26 252). Socioeconomically deprived patients had higher overall 90-day spending compared with nondeprived patients ($61 579 vs $54 557; difference, $3003; P = .001). Spending was higher in socioeconomically deprived patients for index hospitalizations (difference, $1284; P = .005), professional services (difference, $379; P = .002), and readmissions (difference, $1188; P = .008). Inpatient rehabilitation was the only significant difference in post-acute care spending (difference, $469; P = .011).

Conclusions: Medicare spending was higher for socioeconomically deprived CABG in Michigan, indicating systemic disparities over and above patient demographic factors.