Insurance-Based Disparities in Cardiac Allograft Vasculopathy After Heart Transplantation Are Mediated by Care at High-Volume Centers

Abstract

Background

Socioeconomic disadvantage and Medicaid insurance have been linked with inferior survival after heart transplantation, yet the contributing mechanisms remain to be elucidated. We evaluated the association of Medicaid with the development of cardiac allograft vasculopathy (CAV).

Methods

We considered heart transplant recipients aged ≥18 years within the 2004-2022 Organ Procurement and Transplantation Network. CAV was defined as any evidence of angiographic coronary disease. Institutional volume was computed, with hospitals in the highest quartile (≥19 cases/y) categorized as high-volume centers. Patients were stratified by insurance into the Medicaid and Non-Medicaid cohorts. The study period was divided into the pre-Affordable Care Act (ACA; 2004-2013) and post-ACA eras (2014-2022).

Results

Of 37,073 heart transplant recipients, 4875 (13%) were insured by Medicaid. The overall incidence of CAV was 31%. After risk-adjustment, Medicaid insurance was linked with significantly greater likelihood of developing CAV over 5 years (Hazard Ratio [HR], 1.08, 95% CI, 1.01-1.16). Importantly, this effect seems to have emerged in the post-ACA era (Pre-ACA HR, 1.07, 95% CI 0.84-1.36; Post-ACA HR, 1.11, 95% CI, 1.02-1.21). Furthermore, among patients at high-volume centers, Medicaid insurance was linked with similar CAV likelihood (HR, 1.04, 95% CI, 0.95-1.14). Yet, considering those treated at non-high-volume centers, Medicaid was associated with significantly greater CAV hazard (HR, 1.14, 95% CI, 1.03-1.26). Overall, Medicaid remained associated with inferior patient (HR, 1.31, 95% CI, 1.21-1.42) and allograft survival at 5 years (HR, 1.29, 95% CI, 1.19-1.39).

Conclusions

Medicaid-insured recipients faced inferior survival and greater risk of CAV over 5 years. Our work encourages closer follow-up and treatment for vulnerable populations in the months and years post-transplantation.