Impact of preoperative and postoperative anti-obesity medications on early postoperative body mass index reduction after sleeve gastrectomy in pediatrics.

BACKGROUND: Antio-besity medications (OMs) are increasingly used in youth before and after metabolic and bariatric surgery (MBS), but their impact on surgical outcomes remains unclear. OBJECTIVES: This study examined whether perioperative OM exposure affects early postoperative body mass index (BMI) reduction in youth undergoing sleeve gastrectomy (SG), and whether presurgery OM response influences outcomes. SETTING: Pediatric MBS program at a free-standing, tertiary care, safety-net children's hospital. METHODS: A retrospective review was conducted of youth (age 7-21) who underwent SG from November 2023 to March 2025. Youth were stratified based on perioperative OM use, defined as OM use for at least 3 months prior to surgery (n = 74). Among these 74 youth, 47 (64%) resumed OM use within 6 months postoperatively. This group was compared to youth with no OM exposure either before or after SG (n = 20). Primary outcomes were percent change in BMI (%BMI), percent excess BMI loss (% EBMIL), and percent total weight loss (% TWL) at 1-, 2-, and 3-months postsurgery. Secondary outcomes included 90-day postoperative safety and eating behavior changes. A secondary analysis compared "high responders" to OM (>5% BMI loss pre-SG, n = 23) versus "low responders" (≤5%, n = 51). Mixed-effects models adjusted for BMI at consult, age, and time between medical weight management and surgery date. RESULTS: Among 94 youth (mean age 16.5 ± 2.3 years; BMI 50.1 ± 9.7 kg/m; 57% female; 80% Hispanic; 77% publicly insured), OM users had more comorbidities (type 2 diabetes [T2D] 20% versus 0%) and longer presurgical care (P < .05). Median OM duration was 10.2 mo (IQR 6.0-22.0); semaglutide was most common (51/74). Adjusted analyses demonstrated no significant effect of perioperative OM use on postoperative outcomes at 1-, 2-, 3-months. Compared to youth with no OM exposure (n = 20), there were no significant differences in %BMI, %TWL, or %EBMIL at 3 months. Specifically, the between-group differences at 3 months were as follows: %BMI change: -.4 (95% CI: -2.9, 2.2; P = .8), %TWL: -.1 (95% CI: -2.6, 2.5; P = .9), and %EBMIL: +1.4 (95% CI: -.8, 3.5; P = .2). High responders to preoperative OM (n = 23) had greater postoperative weight loss than low responders (n = 51): at 3 months, %BMI change was -19.3% [95% CI: -21.1, -17.6] versus -15.5% [95% CI: -16.7, -14.3]; P < .001. Safety outcomes were similar across groups. CONCLUSIONS: Perioperative OM use alone did not predict short-term weight loss after SG, but high OM responders before surgery had greater benefit. Further research is needed to optimize OM-MBS integration in youth.