Background: The aim of this study was to compare the impact of preexisting diabetes mellitus (pre-DM), posttransplant DM (PTDM), and non-DM on the long-term outcomes of renal transplant recipients (RTRs).
Methods: This is a retrospective observational cohort study of 427 RTRs who underwent transplantation from 1999 to 2008. Patients were divided into non-DM, pre-DM, and PTDM groups. The primary outcome was the composite of doubling of the serum creatinine (SCr) level, graft failure, or death. Secondary outcomes were biopsy-proven acute rejection (BPAR), biopsy-proven interstitial fibrosis and/or tubular atrophy (IF/TA), and individual components of the primary outcome.
Results: A total of 70 patients (16.4%) had pre-DM, 104 (24.2%) had PTDM, and 253 (59.3%) had non-DM. Kaplan–Meier analysis indicated significant differences in the development of the primary outcome: p = 0.003 (log rank test). Relative to the non-DM group, the pre-DM group had a 6.36-fold increased risk [95% confidence interval (CI) 2.43–16.33; p < 0.001), and the PTDM group had a 2.00-fold increased risk (95% CI 1.08–3.73; p = 0.029) for development of the primary outcome. Patients in the pre-DM group had 6.73-fold (95% CI 2.46–18.42; p < 0.001), 4.56-fold (95% CI 1.77–11.78; p = 0.002), and 13.95-fold (95% CI 2.96–65.75; p < 0.001) increased risks for the development of SCr doubling, biopsy-proven IF/TA, and death-censored graft failure, respectively. Patients in the PTDM group had a 2.09-fold (95% CI 1.10–3.99; p = 0.025), increased risk for the development of SCr doubling.
Conclusions: The presence of pre-DM or PTDM significantly impaired kidney allograft outcome.