Background: Sirolimus (SIR) in combination with cyclosporine reduces the incidence of acute rejection in renal transplant recipients. Limited data are available regarding SIR in combination with tacrolimus (TAC).
Methods: A single-center, retrospective review of renal transplant recipients receiving SIR, TAC, and corticosteroids postoperatively was conducted. A total of 118 consecutive renal transplant recipients were included on the basis of availability of day 1 SIR dose information. Seventy-seven patients received an SIR loading dose (SIR-LD) immediately posttransplantation, and 41 patients did not (SIR no loading dose [SIR-NLD]).
Results: The two groups showed similar demographic and transplant characteristics. SIR doses and trough levels were significantly higher in the SIR-LD patients at 1 and 7 days posttransplantation; however, no differences occurred beyond day 7. Patients receiving an SIR-LD experienced significantly better freedom from rejection at 1, 3, and 6 months posttransplantation (P<0.05). This rejection benefit in the SIR-LD group was independent of donor source and use of antibody induction. SIR-LD patients experienced fewer serious infections (12% SIR-LD vs. 27% SIR-NLD, P=0.04) and a lower incidence of delayed graft function (21% SIR-LD vs. 39% SIR-NLD, P<0.05). No significant differences in serum creatinine, hemoglobin, and platelet counts occurred in the first 180 days posttransplantation, but the patients in the SIR-NLD group experienced lower hemoglobin levels at day 30 than those in the SIR-LD group (10.8 g/dL SIR-LD vs. 9.7 g/dL SIR-NLD, P=0.03).
Conclusion: SIR-LD significantly improves early posttransplantation freedom from rejection in renal transplant recipients without increasing other complications.