Effect on kidney graft survival of reducing or discontinuing maintenance immunosuppression after the first year posttransplant

Background. Data are scarce concerning the impact of maintenance immunosuppression dose reductions posttransplant. Methods. Graft survival according to dose reduction or discontinuation of calcineurin inhibitors or mycophenolate mofetil (M M F) after the first year posttransplant was evaluated in 25,045 patients undergoing kidney transplantation during 1996 to 2005. No patient in this analysis had experienced a rejection and all had good graft function before dose reduction. Results. Reduction of cyclosporine (CsA) close to less than or equal to 150 mg/day, tacrolimus to less than or equal to 2 mg/day, or MMF to less than or equal to 1.0 g/day in patients on CsA or less than or equal to 0.5 g/day in patients on tacrolimus during the second year posttransplant was associated with a statistically significant reduction in graft survival (hazard ratios between 1.37 and 1.65). Withdrawal of CsA, tacrolimus, or MMF during year 2 was also associated with an increase in the risk of graft loss compared with continuing treatment (hazard ratio 1.52-1.73). Conclusions. This observational analysis indicates that in kidney transplant patients with good graft function, withdrawing maintenance CsA, tacrolimus or MMF, or reducing the dose of these agents below certain thresholds after the First year posttransplant is associated with a significant risk of graft loss.