Park MH, Tolman DE, Kimball PM.
The impact of race and HLA matching on long-term survival following cardiac transplantation.
Transplant Proc 1997;29(1-2):1460-3.

The purpose of this study was to examine the impact of recipient race on long-term cardiac survival and to measure the effect of HLA matching on Caucasian and African-American survival rates following transplantation. Data were collected from 336 consecutive patients who underwent orthotropic heart transplantation at two hospitals during the period from March 1983 to July 1994.

African Americans were transplanted at a significantly younger age than Caucasians (39.1 years for African Americans and 48.2 years for Caucasians). It is a limitation of this study that the sample size did not permit adjustment by age, as older age is a risk factor for early mortality, thus possibly influencing racial patterns in these data. Additionally, the distribution of disease etiology differed by racial group (Caucasians were more likely to have coronary artery disease and African Americans were more likely to have idiopathic cardiomyopathy). Since these data showed a trend survival pattern related to disease etiology (African Americans with CAD had a lower survival rate than Caucasians with CAD), the inability to adjust for disease etiology (again due to the small sample size) was also potentially problematic.

African Americans received more poorly matched and fewer moderately matched hearts than Caucasians. The 10-year patient survival was lower for African Americans than Caucasians. HLA compatibility at the class I loci modestly improved survival for Caucasians, but class II matching had no effect on their survival. Match for either class I or class II did not significantly improve survival for African Americans. When stratified by matching, there was a modest difference in survival between the two racial groups among those who received poorly matched class I allografts (African American survival was inferior to that of Caucasians), but there were no similar findings among poorly matched class II allografts.

The authors conclude that African American survival is lower than that of Caucasians and this disparity might be even larger if covariates were appropriately controlled. Unlike previous studies, which evaluated short term survival, this study showed that long term survival was associated with class I loci matching rather than class II matching. Finally, class I matching was only beneficial to Caucasians. "Although more African Americans received poorly matched hearts, it is clinically irrelevant to survival and suggests that nonimmunologic factors may be of greater significance for this ethnic group." In contrast Caucasians are immunologically advantaged by matching, "a modest gain that does not justify matching in its current form as a prerequisite to heart allocation."

The small sample size and the limited assessment of clinical and social factors that might be associated with survival are limitations of this study.