Long-term graft survival after conversion from cyclosporin to azathioprine 1 year after renal transplantation. A prospective, randomized study from 1 to 6 years after transplantation

Cyclosporin has improved graft survival after renal transplantation,but cyclosporin nephrotoxicity is a severe clinical problem.Conversion from cyclosporin to azathioprine 1 year after transplantationmight improve long-term graft survival by avoidance of cyclosporinnephrotoxicity. After treatment with cyclosporin and prednisoloneduring the first year after renal transplantation, 106 patientswere consecutively randomized to treatment with either azathiprineand prednisolone or cyclosporin and prednisolone in a prospective,controlled study during the following 5 years, i.e. 6 yearsafter transplantation. Actuarial estimates of graft survivalrates after inclusion in the study were obtained by the product-limitmethod of Kaplan-Meier, and the Mantel-Cox log rank test wasused to compare the two treatment regimens. When the end-pointsin the analyses were cessation of graft function or withdrawalof immunosuppressive treatment due to side-effects, and whenpatients alive with graft function or who had died with a functioninggraft were treated as censored observations, graft survival5 years after inclusion in the study was 57.7±5.2% inthe total material and was the same in both the azathioprinegroup (52.4±7.7%) and the cyclosporin group (63.3±6.7%)(log rank=0.40, P=0.53). When cessation of graft function wasthe only end-point, graft survival 5 years after inclusion inthe study was 73.7±5.2% for the total material with nosignificant differences between the two groups (log rank=0.58,P=0.45). Assuming that cyclosporin and prednisolone were usedduring the first year after renal transplantation, it can beconcluded that conversion to treatment with azathioprine andprednisolone does not deviate from continued treatment withcyclosporin and prednisolone with regard to long-term graftsurvival for the following 5 years.