Outcomes of Metabolic and Bariatric Surgery in Adolescents and Young Adults versus Adults: A Comparative Cohort Study.

BACKGROUND: Metabolic and bariatric surgery (MBS) is an effective treatment for severe obesity, but comparative data between adolescents and young adults (AYA) and adults remain limited. This study aimed to evaluate weight loss and metabolic outcomes after MBS in AYA compared with adults. METHODS: We conducted a retrospective cohort study including AYA (≤ 21 years) and adults (> 21 years) who underwent MBS (sleeve gastrectomy and Roux-en-Y gastric bypass) between 2013 and 2023. Propensity score matching was performed separately for each outcome at each follow-up time point, using nearest-neighbor matching (up to three adult controls per AYA, without replacement) based on baseline characteristics (type of surgery, sex, BMI, prediabetes, hypertension, and dyslipidemia). Weight loss and metabolic outcomes (prediabetes, hypertension, dyslipidemia) were assessed at 1-, 2-, and 3-year follow-up. RESULTS: At 1 year, AYA achieved lower percentage of total weight loss (%TWL) compared with adults (21.2% vs. 32.5%; average treatment effect on the treated (ATT) - 11.2%; 95% CI - 14.2 to - 8.3; p < 0.001). Similar differences were observed at 2 years (25.9% vs. 31.7%; ATT - 5.8%; 95% CI - 9.9 to - 1.7; p = 0.006), and 3 years (29.8% vs. 31.5%; ATT - 1.7%; 95% CI - 5.2 to 1.7; p = 0.324). Prevalence of dyslipidemia was lower in AYA at 3 years (18.9% vs. 35.1%; ATT - 16.2%; 95% CI - 32.1 to - 0.4; p = 0.045). CONCLUSIONS: MBS was effective in both groups, leading to significant weight loss and metabolic improvements. Despite lower early weight loss, AYA achieved metabolic outcomes comparable to adults. A lower prevalence of dyslipidemia was observed among AYA at later follow-up in the primary analysis, although this finding was not robust to exclusion of participants receiving statins at baseline. Larger studies with standardized follow-up and longer-term observation are warranted to confirm these findings.