Body Mass Index and Early Graft Function After Pediatric Kidney Transplantation

Background Nutritional status influences outcomes after pediatric kidney transplantation. While obesity is associated with delayed graft function (DGF) in adults, prior pediatric literature has reported inconsistent associations between body mass index (BMI) and early graft function, leaving uncertainty about whether higher BMI contributes to early dysfunction in children. Methods We studied pediatric kidney‐only recipients in the Organ Procurement and Transplantation Network (OPTN) registry. Exclusions were age < 2 years, prior or multi‐organ transplants, or missing BMI, dialysis, or hospital length of stay (HLOS) data. BMI was classified using Centers for Disease Control and Prevention growth charts. Outcomes were DGF, slow graft function (SGF), and HLOS. Trend testing evaluated ordered associations across BMI categories. Logistic regression estimated adjusted associations between BMI category and DGF and SGF, and linear regression was used for HLOS. Results Among 9098 recipients, the incidence of DGF increased progressively across BMI groups, from 3.9% in underweight to 5.9% in obese recipients (trend p = 0.016). In adjusted models, each higher BMI category was associated with greater odds of DGF (OR 1.16, 95% CI 1.07–1.27, p < 0.001) and SGF (OR 1.20, 95% CI 1.06–1.35, p = 0.004). HLOS was modestly longer in higher‐BMI groups (median 9 vs. 8 days; p < 0.001). Conclusion Higher BMI is associated with modest differences in early graft dysfunction in pediatric kidney transplantation. Trend analyses demonstrate a graded association between BMI and DGF and SGF, with small absolute differences across BMI categories.