Objective: The aim of this study was to assess the incidence of posttransplantation diabetes mellitus (PTDM) in renal allograft recipients and to investigate factors contributing to the onset and progression of PTDM and its underlying pathogenic mechanism(s).
Research design and methods: A total of 77 patients with normal glucose tolerance (NGT) were enrolled in this study. An oral glucose tolerance test was performed 1 week before transplantation and repeated at 1 and 7 years after transplantation.
Results: The overall incidence of PTDM was 39% at 1 year and 35.1% at 7 years posttransplantation. The incidence for each category of PTDM was as follows: persistent PTDM (P-PTDM) (patients who developed diabetes mellitus within 1 year of transplantation and remained diabetic during 7 years), 23.4%; transient PTDM (T-PTDM) (patients who developed diabetes mellitus during the 1st year after transplantation but eventually recovered to have NGT), 15.6%; late PTDM (L-PTDM) (patients who developed diabetes mellitus later than 1 year after transplantation), 11.7%; and non-PTDM during 7 years (N-PTDM7) (patients who did not develop diabetes mellitus during 7 years), 49.3%. Older age (> or = 40 years) at transplantation was a higher risk factor for P-PTDM, whereas a high BMI (> or = 25 kg/m2) and impaired fasting glucose (IFG) at 1 year posttransplantation were higher risk factors for L-PTDM. Impaired insulin secretion rather than insulin resistance was significantly associated with the development of P- and L-PTDM.
Conclusions: Impaired insulin secretion may be the main mechanism for the development of PTDM. Older age at transplantation seems to be associated with P-PTDM, whereas a high BMI and IFG at 1 year after transplantation were associated with L-PTDM.