Post-transplant diabetes mellitus: incidence, predicting factors and outcomes

Purpose: To identify predictors and evaluate outcomes of posttransplant diabetes mellitus (PTDM) and to investigate the effect of treatment modalities on outcomes. Methods: The database of a tertiary medical center was searched for all adult patients without prior diabetes who underwent lung, liver, or heart transplantation between January 1, 2012 and June 30, 2018. Patients in whom PTDM (defined as HbA1C ≥ 6.5% at least 3 months post transplantation) developed during follow-up (mean 3.32 years) were identified. Risk factors for PTDM, determined by regression analysis and clinical outcomes [all-cause mortality, severe infections, graft loss, and major adverse cardiovascular events (MACE)], were compared between those who developed PTDM and those who did not; in the former, insulin-based therapy was compared with non-insulin regimen. Results: The cohort included 281 transplant recipients: 158 lung, 109 liver, and 14 heart. PTDM was diagnosed in 60 (21.35%) patients at a mean of 11.3 ± 12.89 months post transplantation. The only significant independent risk factor for PTDM was age (HR 1.028, 95% CI = 1.002–1.054, P = 0.0314). PTDM was associated with higher rates of severe infections (HR 2.565, 95% CI = 1.626–4.050, P < 0.0001), MACE (HR 1.856, 95% CI = 1.013–3.401, P = 0.0454) and death (HR 1.840, 95% CI = 1.024–3.304, P = 0.0413). Recipients treated with insulin-based regimens had a higher risk of severe infections (HR 2.579, 95% CI = 1.640–4.055, P < 0.0001), MACE (1.925, 95% CI = 1.074–3.451, P = 0.0278) and death (HR 1.960, 95% CI = 1.071–3.586, P = 0.0291). Conclusions: PTDM is associated with increased mortality and poor outcomes in lung, liver, and heart transplant recipients. Early identification and aggressive treatment of PTDM and its associated cardiometabolic risk factors may improve outcomes.