Abstract / Summary
Abstract Background and Aim Higher pre-transplant body mass index (BMI) is associated with post-transplant disorders of glucose metabolism, but the relationship between baseline BMI and the evolution of glycemia during the first year after kidney transplantation remains incompletely characterized. This study aimed to evaluate the association between pre-transplant BMI and diabetes-range glycemia during the first post-transplant year in kidney transplant recipients without pre-existing diabetes mellitus. Methods This retrospective cohort study included 212 adult kidney transplant recipients without pre-existing diabetes mellitus. Baseline anthropometric and laboratory measurements were obtained before transplantation, and fasting plasma glucose (FPG) and HbA1c were assessed at 3, 6, and 12 months after transplantation. The primary outcome was diabetes-range glycemia, defined as FPG ≥ 126 mg/dL or HbA1c ≥ 6.5% at any follow-up visit. Associations with the primary outcome were evaluated using multivariable logistic regression, while longitudinal glycemic trajectories were examined using linear mixed-effects models including time, baseline BMI, and a time × BMI interaction. ROC analysis was used to assess the discriminatory performance of pre-transplant BMI. Results Diabetes-range glycemia occurred in 121 of 212 recipients (57.1%) during the first post-transplant year. Only 12 recipients (5.7%) met the criterion at a single follow-up visit, whereas 109 (51.4%) had diabetes-range glycemia at two or more visits. Higher pre-transplant BMI was significantly associated with the primary outcome; in the multivariable logistic regression model, each 1 kg/m² increase in BMI was associated with higher odds of diabetes-range glycemia (adjusted OR 1.21, 95% CI 1.09–1.34; p < 0.001). Longitudinal mixed-effects models demonstrated significant time × BMI interactions for both FPG and HbA1c (both p < 0.001), indicating greater post-transplant glycemic increases among recipients with higher baseline BMI. In exploratory ROC analysis, pre-transplant BMI showed an AUC of 0.823 (95% CI 0.760–0.881), with a Youden-derived cut-off of 26.0 kg/m². Conclusion Higher pre-transplant BMI was associated with diabetes-range glycemia and with a greater longitudinal increase in glycemic measures during the first year after kidney transplantation. These findings support the importance of pre-transplant metabolic risk assessment, while the exploratory BMI cut-off identified in this cohort requires external validation. Clinical trial number Not applicable.