Do immunosuppressants cause posttransplant diabetes mellitus?

Background. Posttransplant diabetes mellitus (PTDM) was originally described by Starzl in 1964. The incidence is around 3-46%, according to several reports. Etiologies and risk factors of PTDM have been discussed after it was described and recognized as a complication of renal transplantation. Methods. Twenty-five consecutive renal transplants in 24 recipients were reviewed, and 3 cases of posttransplant diabetes mellitus were found. Cyclosporine A (CsA), Azathioprine (Aza) dose and maintenance dose of Prednisolone (Pred.), rejection episodes, total dosage of steroid used at the time of acute rejection were carefully recorded and analyzed. Results. The mean age of 3 living-related and 22 cadaveric transplant recipients was 32.7 ± 7.5 and 33.5 ± 6.8 years in PTDM and non-PTDM patients, and the onset of PTDM was, on the average, 11.3 ± 0.6 months. Comparative studies between non-PTDM and PTDM groups showed that age, rejection episodes, total dose of methylprednisolone used in acute rejection, CsA level, and dosage of CsA, Aza and prednisolone at 1, 6, 12 and 24 months were not significantly different from one another. Conclusions. No significant risk factors or definitive mechanism involved in the development of PTDM were identified in this study. It is suggested that immunosuppressants are involved in the occurrence of PTDM, and probably neither a single factor is responsible nor is dose dependency involved.