Potential Differences in Kidney Allograft Outcomes Between Ethnicities When Converting to Sirolimus Base Immunosuppression

OBJECTIVE: The aim of this study was to determine whether ethnicity impacts graft outcomes in kidney transplant patients converted to sirolimus (SRL) and maintained on either calcineurin inhibitors (CI) or mycophenolate mofetil (MMF) with steroids. METHODS: This study analyzed kidney transplants converted to SRL and transplanted between July 1991 and April 2007. Patients were divided into 4 groups: group 1: African-Americans converted to SRL + CI; group 2: non-African-Americans converted to SRL + CI; group 3: African-Americans converted to SRL + MMF; group 4: non-African-Americans converted to SRL + MMF. RESULTS: A total of 242 patients was included. Demographics, baseline immunosuppression, and reason for SRL conversion were similar among groups. Patients converted to SRL + CI regimens had significantly higher rates of acute rejection before SRL conversion, but equal rates after conversion. Development of proteinuria was similar across groups. African-American patients converted to SRL + MMF tended to have poorer outcomes compared with African-American patients converted to SRL + CI. Non-African-American patients converted to SRL + MMF tended to have better graft outcomes compared with non-African-American patients converted to SRL + CI. CONCLUSIONS: African-Americans converted to SRL may benefit from continued CI, whereas non-African-Americans converted to SRL seem to have better outcomes with MMF. Further prospective studies are warranted to confirm these findings.