Pre-transplant HbA1c and risk of diabetes mellitus after kidney transplantation: a single center retrospective analysis

Background Post-transplant diabetes mellitus occurs in 10-40% of kidney transplant recipients and is associated with increased risk of developing cardiovascular diseases. Early identification of patients with a higher risk of developing diabetes could allow to take timely measures. However, no validated model exists to predict the risk of post-transplant diabetes mellitus. Methods This retrospective study includes 267 adult patients who underwent kidney transplantation at the Antwerp University Hospital between January 2014 and August 2021. Post-transplant diabetes mellitus was diagnosed based on the American Diabetes Association definition at 3 months post-transplant. First, a logistic regression analysis was used to identify predictors for post-transplant diabetes mellitus. Second, criteria to identify patients with a high risk (> 35%) of developing post-transplant diabetes mellitus at 3 months were established. Results At 3 months post- transplantation, 54 (20.2%) patients developed post-transplant diabetes mellitus. Univariable analysis showed that age, body mass index and HbA1c on the day of transplantation were associated with post-transplant diabetes mellitus. However, in a multivariable model with the same parameters, only HbA1c remained statistically significant. An absolute increase in HbA1c of 0.1% increases the odds for developing post-transplant diabetes mellitus by 28% (95% confidence interval 1.15-1.42). An HbA1c level >= 5.3% at transplantation, regardless of age or body mass index, is sufficient to identify patients with a post-transplant diabetes mellitus risk of >= 35% with a positive predictive value of 39% and a negative predictive value of 88%. Conclusions The HbA1c value at transplantation was the strongest predictor for post-transplant diabetes mellitus at 3 months post-transplant. Furthermore, at least in our population, a pre-transplant HbA1c of >= 5.3% can be used as an easy tool to identify patients at high risk of early post-transplant diabetes mellitus.