Kidney outcomes three years after bariatric surgery in severely obese adolescents

A significant number of severely obese adolescents undergoing bariatric surgery have evidence of early kidney damage. To determine if kidney injury is reversible following bariatric surgery, we investigated renal outcomes in the Teen-Longitudinal Assessment of Bariatric Surgery cohort, a prospective multicenter study of 242 severely obese adolescents undergoing bariatric surgery. Primary outcomes of urine albumin-to-creatinine ratio and cystatin C-based estimated glomerular filtration rate (eGFR) were evaluated preoperatively and up to 3 years following bariatric surgery. At surgery, mean age of participants was 17 years and median body mass index (BMI) was 51 kg/m2. In those with decreased kidney function at baseline (eGFR under 90 mL/min/1.73m2), mean eGFR significantly improved from 76 to 102 mL/min/1.73m2 at three-year follow-up. Similarly, participants with albuminuria (albumin-to-creatinine ratio of 30 mg/g and more) at baseline demonstrated significant improvement following surgery: geometric mean of ACR was 74 mg/g at baseline and decreased to 17 mg/g at three years. Those with normal renal function and no albuminuria at baseline remained stable throughout the study period. Among individuals with a BMI of 40 kg/m2 and more at follow-up, increased BMI was associated with significantly lower eGFR, while no association was observed in those with a BMI under 40 kg/m2. In adjusted analysis, eGFR increased by 3.9 mL/min/1.73m2 for each 10-unit loss of BMI. Early kidney abnormalities improved following bariatric surgery in adolescents with evidence of preoperative kidney disease. Thus, kidney disease should be considered as a selection criteria for bariatric surgery in severely obese adolescents who fail conventional weight management.