Metabolic and Bariatric Surgery in Adolescents: A Single-Center Study of Efficacy and Outcome Predictors

Introduction: Some adolescents undergoing metabolic and bariatric surgery (MBS) have suboptimal responses to surgery, particularly over the longer term. This study aimed to quantify changes in weight loss over time in adolescents undergoing MBS and identify preoperative predictors of weight loss. Methods: This was a prospective, observational cohort study of 73 adolescents (12–19 years) living with obesity undergoing MBS. Absolute and relative changes in anthropometric and biochemical parameters were evaluated up to 30 months. Changes in anthropometric measures were assessed using a mixed residual maximal likelihood model. Univariable and multivariable logistic regression were used to identify predictors of a >35.0% reduction in BMI z-score from baseline to 12 months. Predictive accuracy was assessed by area under the receiver operating characteristics analysis. Results: Most patients (87.7%) underwent laparoscopic sleeve gastrectomy (12.3% underwent laparoscopic sleeve bypass). Weight, weight z-score, BMI, and BMI z-score significantly decreased over 30 months (p < 0.001) up to a −53.8% relative change in BMI z-score at 30 months. There was a significant increase (p = 0.02) in high-density lipoprotein cholesterol and a significant decrease in triglycerides (p = 0.0001) and ALT (p = 0.0004) after surgery. A higher preoperative BMI was associated with a reduced odds (OR 0.89, 95% CI 0.79–0.97, p = 0.03) of a >35% reduction in BMI z-score at 12 months. A baseline BMI >52.6 kg/m² had a sensitivity of 100% and specificity of 40.6% for detecting a >35.0% postoperative decrease in BMI z-score. Conclusion: MBS results in sustained weight loss in adolescents. A high preoperative BMI predicts resistance to optimal weight loss after surgery and argues against delaying surgery once eligibility thresholds are met.