Abstract 2963: Association of Race and Socioeconomic Position with Graft Failure in Heart Transplant Recipients

Abstract

Race has been associated with patient survival in heart transplant (HT) recipients. We hypothesized that this association is mediated by socioeconomic (SE) factors. Block groups (average population 1000) are the smallest units of population in US census database with available SE data. We assessed whether SE position, determined for the block group of patient residence at time of HT, is associated with graft failure in HT recipients. We used the US census 2000 database to extract 6 SE variables of wealth, income, education and occupation and calculated a previously validated summary SE score for 520 patients who underwent first HT at one of 4 Boston centers during 1996–2005. Cox proportional hazards modeling was used to compare the risk of graft failure (time to death or re-transplant) in the lowest quartile SE group (low SE group, n = 129) with that of remaining patients (controls, n = 391). Low SE patients were younger (median age 48 yrs versus 52 yrs for controls, P < 0.015) and more likely to be nonwhite (32% versus 9% of controls, P = 0.001). The two SE groups were similar with respect to gender, listing status, cardiac diagnosis, hemodynamic support, year of HT and prevalence of diabetes, smoking and hypertension. Graft failure occurred in 142 HT patients (135 deaths, 7 re-transplants). Early Graft failure (within 6 months) was associated with earlier era (before 2001), pre-HT extracorporeal membrane oxygenation or ventricular assist device but not with age, cardiac diagnosis, race or low SE position. In patients who survived at least 6 months (conditional survival), nonwhite race (HR 2.0, 95% CI 1.3–3.3, P = 0.004), low SE position (HR 1.6, CI 1.1–2.5, P = 0.03) and pre-HT smoking (HR 1.6, CI 1.0 –2.4, P = 0.03) were all associated with subsequent graft failure. In multivariable analysis, nonwhite race (HR 1.9, CI 1.2–3.3) remained a significant predictor of late graft failure after controlling for low SE position (HR 1.3, CI 0.8 –2.1, P = 0.24) and pre-HT smoking (HR 1.6, CI 1.1–2.5, P = 0.03). There is no association of early post-HT survival with race or low SE position. Nonwhite race is associated with increased risk of death or re-transplant after 6 months of HT. Low SE position explains only a small fraction of this association.