Post-transplant diabetes mellitus: Increasing incidence in renal allograftrecipients transplanted in recent years

Background. Post-transplant diabetes mellitus (PTDM) is a serious complicat ion of transplantation caused by immunosuppressive drugs. In this study, we assessed the incidence of PTDM and the factors that are associated with th e development of this complication. Methods, The study population included 2078 non-DM renal allograft recipien ts, transplanted since 1983 in one institution. PTDM was diagnosed by the r equirement of hypoglycemic medications, starting more than 30 days after tr ansplantation. Posttransplant, all patients received cyclosporine (CsA) and prednisone, but none of these patients received tacrolimus. Results. At 1, 3, 5, and 10 years after transplantation, 7, 10, 13, and 21% of patients developed PTDM. By multivariate Cox, the following variables c orrelated with a more rapid increase in the number of PTDM cases: (I) older age (RR = 2.2 comparing patients younger or older than 45 years, P < 0.000 1), (2) transplant done after 1995 (RR = 1.7, P = 0.003), (3) African Ameri can race (RR = 1.6, P = 0.003), and (4) higher body weight at transplant (R R = 1.4, P<0.0001). Compared with before 1995, since 1995, the percentage o f patients with PTDM has increased from 5.9 to 10.5% at one year and from 8 .8 to 16.9% at three years. This increase was statistically independent fro m all other variables tested. However, since 1995, recipients have become s ignificantly heavier (P ( 0.0001) and older (P ( 0.0001), and the average C sA level has increased significantly (P < 0.0001). Also. since 1995. the cu mulative dose of corticosteroids has declined (P ( 0.0001); patients receiv ed a newer, better absorbed preparation of CsA and received mycophenolate m ofetil. Conclusions. The risk of PTDM increases continuously with time post-transpl ant. There has been an increase in the incidence of PTDM in patients transp lanted recently, and that increase can be explained only partially by chang es in the recipients' characteristics. We postulate that this increase may be due to the introduction of better absorbed CsA formulations that result in higher blood levels and higher cumulative exposure to this diabetogenic drug.