Age-specific impact of different immunosuppressive regimens on kidney transplant outcomes: clinical evidence from the scientific registry of transplant recipients

Abstract

Background Although older kidney transplant recipients have a higher risk of side effects leading to infection and malignancies, the impact of different immunosuppressive regimens on clinical outcomes in this group remains unclear. Methods Retrospective cohort study analyzing data from the Scientific Registry of Transplant Recipients database. Kidney transplant recipients were categorized according to age categories (18–64 and >65 years) and immunosuppressive maintenance regimens: tacrolimus/mycophenolate mofetil (Tac-MMF), Tac/mTOR-inhibitor (Tac-mTORi), cyclosporin/MMF (CsA-MMF) and mTORi-MMF. The primary endpoint was overall survival. Results Among the 112, 952 patients analyzed, overall survival rates at 2-, 3- and 5-years post-transplant were 95.6%, 93.7% and 87.6% respectively. No significant differences in the risk of mortality, graft loss or acute rejection were observed between patients treated with Tac-mTORi and those receiving Tac-MMF. Furthermore, no significant interactions were found between the maintenance immunosuppressive regimens and recipient age groups. Regarding kidney function, younger patients on the Tac-mTORi compared with Tac-MMF regimen exhibited a lower mean eGFR throughout the follow-up period compared to those on Tac-MMF. In contrast to this younger cohort, older patients treated with Tac-mTORi did not experience a significant additional decline in renal function. Conclusion In this study, Tac-mTORi and Tac-MMF showed comparable results regarding patient survival, graft survival and rejection rates. Because older patients remain at higher risk for drug-related side effects, including infections, metabolic disorders and malignancies, these results highlight the critical need for individually immunosuppressive regimens in older transplant recipients and warrant further prospective validation.