Comparing survival outcomes for kidney transplant recipients with pre-existing diabetes versus those who develop post-transplantation diabetes.

Abstract

Introduction: The aim of this study was to compare the management strategy and clinical outcomes for kidney transplant recipients with pre-transplant versus post-transplantation diabetes (PTDM) in a contemporary cohort.

Methods: This is a single-centre, retrospective. observational study of kidney transplant recipients between 2007 and 2018 with follow-up to 31 December 2020. Data were extracted from hospital electronic patient records, with clinical outcomes linked to national data sets. PTDM was diagnosed by international consensus guidelines. Unadjusted and adjusted survival outcomes were assessed with Kaplan-Meier curves and Cox regression models, respectively, with PTDM handled as a time-varying covariate.

Results: Data were analysed for 1,757 kidney transplant recipients, of whom 11.8% (n = 207) had pre-transplant diabetes, and 13.8% (n = 243) developed PTDM with median time to onset 108 days (IQR 46-549 days). Median follow-up was 1,839 days (IQR 928-2985 days). Disparate management strategies were observed, although insulin was the commonest glucose-lowering therapy for all patients with diabetes. In adjusted models, PTDM was associated with lower mortality (HR 0.663, 95% CI 0.543-0.810) and pre-diabetes with higher mortality (HR 1.675, 95% CI 1.396-2.011). However, if analyses are restricted to those with at least 5-year follow-up, then PTDM has no association with mortality (HR 0.771, 95% CI 0.419-1.096), but pre-transplant diabetes remains associated with higher mortality (HR 2.029, 95% CI 1.367-3.012).

Conclusions: Pre-transplant diabetes remains associated with increased mortality risk after kidney transplantation, but PTDM effects are time dependent. Development of PTDM should be encouraged as a mandated registry return to study the long-term impact on survival outcomes.