• Elevated body mass index is an independent risk factor for delayed early renal function recovery and prolonged hospital stay after kidney transplantation.
• Each 1 kg/m² increase in body mass index is associated with a 38 μmol/L rise in postoperative day 1 creatinine and a 32 mL reduction in urine volume.
• Obese recipients (BMI ≥ 28 kg/m²) had significantly higher age, lower living donor proportion, and worse early postoperative outcomes.
• Individualized perioperative management, including enhanced monitoring and tailored immunosuppression, is recommended for obese kidney transplant recipients.