Albuminuria after renal transplantation: maintenance with sirolimus/low-dose tacrolimus vs. mycophenolate mofetil/high-dose tacrolimus

Maintenance immunosuppression with sirolimus (SRL) in renal transplantation has been associated with proteinuria. We report long-term outcomes of kidney transplant recipients maintained on steroid-free regimens, either SRL with low-dose tacrolimus (SRL/L-Tac) or mycophenolate mofetil (MMF) with high-dose tacrolimus (MMF/H-Tac). We conducted a case-matched study of 50 patients receiving MMF/H-Tac, matched 1:2 with 100 patients maintained on SRL/L-Tac. All patients were induced with rabbit antithymocyte globulin followed by early steroid withdrawal. Comparisons were made of patient and graft survival, graft function, acute rejection, and albuminuria. There were no significant differences between the SRL/L-Tac and MMF/H-Tac groups for patient survival, graft survival, occurrence of acute rejection, or graft function. There was no difference in the proportion of patients with albumin/creatinine ratio (ACR) ≥300 μg/mg (19% vs. 20%), but more patients in the SRL group were receiving renin-angiotensin system blocking agents (72% vs. 53%, p = 0.04). Only flushing the donor kidney with histidine-tryptophan-ketoglutarate solution (vs. UW solution) was predictive of albuminuria. Long-term outcomes are similar at our center for kidney transplant patients receiving either SRL/L-Tac or MMF/H-Tac. Although the occurrence of albuminuria was not different, significantly more SRL-treated patients were receiving antiproteinuric medications.