Beneficial effects of conversion from cyclosporin to azathioprine after kidney transplantation

Immunosuppression with cyclosporin after renal transplantation is associated with better graft survival than is azathioprine treatment. However, nephrotoxicity and other side-effects have led to regimens that change treatment to azathioprine shortly after transplantation. Conversion has beneficial effects in the short term on renal function and hypertension. We report long-term follow-up (minimum 5 years) of 128 patients who had received a first or second cadaveric kidney graft and were treated with cyclosporin and prednisone; they were randomly assigned 3 months after transplantation to groups continuing to receive cyclosporin (n = 68) or changing to azathioprine (n = 60). 8 years after transplantation, patient survival was 75.3% in the cyclosporin group and 85.9% in the azathioprine group (p = 0.14) and graft survival was 64.0% and 76.6%, respectively (p = 0.38). The frequency of cardiovascular death with a functioning graft was 8% higher in the cyclosporin group (95% CI -1 to 18). The relative risk of graft loss after conversion to azathioprine compared with graft loss after conversion to azathioprine compared with cyclosporin maintenance was 0.71 (0.37-1.38) and the relative risk of patient death was 0.57 (0.23-1.41). The cyclosporin group had poorer mean creatinine clearance (17.8 mL/min [8.1-27.5] lower than azathioprine group) and a higher proportion needed hypertensive drugs (20% [4-36] more). Gout was found in 9 cyclosporin-treated patients and 1 azathioprine-treated patient (difference 12% [3 to 20]). Elective conversion from cyclosporin to azathioprine 3 months after transplantation is safe and cost-effective.