Background: Prospective data regarding immunosuppression and rejection in African American patients receiving modern immunosuppressive regimens are sparse.
Methods: One-year data were analyzed from 901 tacrolimus-treated de novo kidney transplant patients in the prospective Mycophenolic Acid Observational Renal Transplant registry.
Results: Mean tacrolimus dose was significantly higher in African Americans (n=217) versus non-African Americans (n=684), but mean tacrolimus trough concentrations were similar. The proportion of patients receiving mycophenolic acid dose equal to or more than 2000 mg per day (mycophenolate mofetil equivalents) was significantly higher with enteric-coated mycophenolate sodium versus mycophenolate mofetil at month 6 among African Americans and at month 3 in non-African Americans, but rates of acute rejection and adverse events (including gastrointestinal events) were similar. The 1-year incidence of biopsy-proven acute rejection (BPAR) was 14.1% in African Americans versus 7.5% in non-African Americans. On multivariate analysis, African American ethnicity was associated with a higher risk of BPAR (hazard ratio, 1.93; 95% confidence interval, 1.19-3.09; P=0.007). Mean (standard deviation) glomerular filtration rate at month 12 estimated by the Chronic Kidney Disease Epidemiology Collaboration formula was 59.2 (22.2) mL/min/1.73 m in African Americans versus 58.8 (19.9) mL/min/1.73 m in non-African Americans (confidence interval of the difference, -3.4 to 4.3; P=0.83).
Conclusion: This observational study confirms that African Americans require higher doses of tacrolimus to achieve target trough concentrations and are more likely to experience BPAR during the first year after kidney transplantation despite modern immunosuppression regimens. In our 1-year study, this was not associated with significantly inferior graft survival.