Pretransplant Diabetes Mellitus and Kidney Transplant Outcomes: A Systematic Review and Meta-Analysis.

Background: Studies have shown that kidney transplantation is affected by pretransplant comorbidities. However, their impacts on mortality and graft loss remain inconsistent. Therefore, the purpose of our study was to collect data from multiple studies to analyze the impact of pretransplant diabetes mellitus on kidney transplant outcomes.

Method: We conducted comprehensive searches of the PubMed, Embase, and Web of Science databases to identify studies that met the inclusion criteria. All-cause mortality and graft loss were compared between patients with pretransplant diabetes mellitus and patients without pretransplant diabetes mellitus. The impact of pretransplant diabetes mellitus was assessed using pooled hazard ratios and 95% confidence intervals.

Result: This meta-analysis included 103,983 kidney transplant recipients with diabetes mellitus and 271,667 kidney transplant recipients without diabetes mellitus. All-cause mortality was 68% (HR:1.68, 95% CI 1.65-1.71, P < .01) greater in patients with pretransplant diabetes mellitus than in patients without diabetes mellitus. Additionally, graft loss was 11% (HR:1.11, 95% CI 1.07-1.15, P < .01) greater in diabetic patients than in nondiabetic patients. The heterogeneity in the 2 analyses was very significant and meta-regression was used to determine the source of heterogeneity. Unfortunately, it was not found in the analysis of all-cause mortality. However, in the analysis of graft loss, sample size and median age at transplantation may be sources of high heterogeneity.

Conclusion: Pretransplant diabetes mellitus is associated with increased risk of mortality and graft loss. However, due to significant heterogeneity and insufficient evidence, further studies are still needed to support our conclusions.