Clinical profile and graft outcomes of post-transplant diabetes mellitus in renal transplant recipients: a retrospective study from a tertiary care center in South India

Post-transplant diabetes mellitus (PTDM) is a common metabolic complication following kidney transplantation and is associated with increased morbidity. Data on its clinical profile and impact on graft outcomes in Indian populations remain limited. This study aimed to evaluate the incidence, risk factors, and graft outcomes of PTDM in renal transplant recipients at a tertiary care center in South India. This single-center retrospective observational study included adult renal transplant recipients without pre-existing diabetes who underwent transplantation between January 2016 and June 2024 and had at least one year of follow-up. Hyperglycemia occurring within the first 3 months after transplantation was classified as transient hyperglycemia, whereas PTDM was diagnosed when diabetes persisted or first developed ≥ 3 months after transplantation according to American Diabetes Association criteria. Demographic, clinical, transplant-related, and post-transplant variables were analyzed. Factors associated with PTDM were evaluated using univariate and primary multivariable logistic regression analyses. Death-censored graft survival was assessed using Kaplan–Meier analysis. Among 178 recipients, PTDM developed in 33 (18.5%), with a median onset of 4 months (IQR 4–9). Transient hyperglycemia occurred in 57 (32.0%) recipients, of whom 20 (35.1%) subsequently developed PTDM. In the primary multivariable model, transient hyperglycemia (adjusted odds ratio [AOR] 4.24, 95% CI 1.81–9.94; p = 0.001), pre-transplant dysglycemia (AOR 5.16, 95% CI 1.27–20.95; p = 0.022), and deceased-donor transplantation (AOR 4.47, 95% CI 1.32–15.12; p = 0.016) were independently associated with PTDM, whereas age was not (AOR 1.04 per year, 95% CI 0.99–1.08; p = 0.086). In a sensitivity analysis incorporating family history of diabetes, family history remained strongly associated with PTDM (AOR 13.37, 95% CI 4.29–41.71; p < 0.001), while transient hyperglycemia remained independently associated (AOR 3.97, 95% CI 1.54–10.24; p = 0.004). UTI occurrence and episode burden were not significantly associated with PTDM. Death-censored graft survival did not differ significantly between recipients with and without PTDM (log-rank p = 0.487). PTDM developed in approximately one-fifth of renal transplant recipients, with onset occurring predominantly during the early post-transplant period. Transient hyperglycemia, pre-transplant dysglycemia, and deceased-donor transplantation were independently associated with PTDM. Family history of diabetes remained strongly associated in sensitivity analysis. No significant difference in death-censored graft survival was observed between recipients with and without PTDM.