Racial disparities in graft loss following kidney transplantation - a single center experience

Background/significance: Although national success rates in kidney transplantation are relatively high, the survival rate in African Americans (AA) drops progressively (1 year- 89.9%, 3 year-72.9%, 5 year-58.65%) compared to Caucasians (1 year-92.3%, 3 year-83.8%, 5 year-75.5%). Since 1998, Aurora St. Luke’s Medical Center (ASLMC) has performed 317 kidney transplantations, however the survival data and variables affecting graft outcomes across different racial groups is unclear. Purpose: The goal of this study was to compare survival rates and graft function across different racial groups following kidney transplantation at ASLMC. Methods: This study was approved by the Aurora Institutional Review Board. A comprehensive retrospective chart review of all adult kidney transplant patients (n=209) from 1999-2009 was performed. Patients that had more than one transplant were excluded from the study. Patient information included demographics, BMI, cardiovascular risk factors, time on dialysis and cold ischemia time, date of rejection, medication adherence, lab analyses and date of death. Descriptive statistics and uni-variate analysis was performed with statistical significance set at alpha\u3c0.05. Time to event analyses included patients’ survival as primary outcome and graft loss as secondary outcome. Significant predictors of graft loss were evaluated by logistic regression modeling. Results: Out of 209 patients, there were 34 AA, 43 other (32 Hispanic and 12 Asian) and 132 C. While the distribution of demographic variables were similar across all racial groups, the mean time to dialysis for AA was slightly higher compared to C (p=0.057). AA had lower 5 year survival (85.7%) compared to C (93.2%) but this was not statistically significant (p=0.141). At 5 years post-transplant, graft function was significantly lower (p=0.016) in AA compared to C (77.1%) vs. C (92.4%). Although there was no single independent contributor identified to graft loss, logistic regression modeling showed that AA who had low medication compliance also had the lowest graft survival (p=0.030). Correspondingly, 3 year serum prograf levels were also significantly lower in AA compared to C (p=0.038). Conclusion: In this retrospective study, AA had higher graft loss following kidney transplantation, although the reasons are not very clear. Race and medication non-compliance are both possible factors that could affect graft survival indicating the need for larger prospective interventional studies to improve medication adherence