A comparison of discharge immunosuppressive drug regimens in primary cadaveric kidney transplantation

BACKGROUND: Finding the best combination of immunosuppression is an important challenge in kidney transplantation. Current short-term (1- and 3-year) allograft survival is quite good, making it difficult to determine differences in therapeutic regimens without large sample sizes. Using data from the United Network for Organ Sharing/Organ Procurement and Transplantation Network database, the current study provides substantial statistical power to analyze the outcomes for different immunosuppressive regimens. METHODS: To compare the effects of four discharge regimens (cyclosporine and azathioprine CYA+AZA], CYA and mycophenolate mofetil MMF], tacrolimus TAC]+AZA, and TAC+MMF) on long-term survival, a multivariate Cox regression analysis was conducted on 19246 primary cadaveric kidney transplants during 1995 to 1998. RESULTS: Compared with CYA+AZA, the combination of CYA+MMF was associated with a 10% reduced risk of graft loss (relative risk RR] 0.90, 95% confidence limit CL] 0.84-0.96, P<0.001), whereas TAC+AZA was associated with an 18% reduced risk (RR 0.82, 95% CL 0.67-1.005, P=0.06) and TAC+MMF with a 20% reduced risk of graft loss (RR 0.80, 95% CL 0.71-0.89, P<0.001). All three regimens benefited patients regardless of delayed graft function (DGF) or early acute rejection status. In addition, in the absence of DGF, the combinations of CYA+MMF, TAC+AZA, and TAC+MMF were associated with a reduced risk of mortality compared with CYA+AZA. CONCLUSIONS: The major finding of this study was improved graft and patient survival associated with TAC+MMF and CYA+MMF in patients with or without DGF or early acute rejection.