# Preoperative Weight Trends in Adolescents Undergoing Metabolic and Bariatric Surgery

## TL;DR

This study examines how adolescents' weight changes before bariatric surgery and how these changes affect long-term BMI reduction after surgery.

## Contribution

The study provides new insights into preoperative weight trends and their impact on postoperative outcomes in adolescent bariatric surgery patients.

## Key findings

- Most adolescents maintained within ±5% of their baseline weight before surgery.
- Postoperative BMI reduction was less among those who gained weight preoperatively.
- No significant differences in weight-related behaviors were found between groups.

## Abstract

Preoperative weight changes, predictors of weight changes, and subsequent implications on postoperative BMI reduction in adolescents preparing for bariatric surgery (MBS) have not been well described.

Teen–Longitudinal Assessment of Bariatric Surgery (Teen‐LABS) consortium (prospective, observational MBS study at five centers from 2007 to 2011) participants who completed the preoperative phase within 3–9 months of initial visit were included in this analysis (n = 123). Participants were categorized into preoperative weight groups: > 1% loss, stable, or > 1% gain. Demographic, anthropometric, socioeconomic, medical, and behavioral data were analyzed. Postoperative percent BMI loss at 1, 5, and 8 years by weight group was compared.

Preoperatively, 50% of participants lost weight, 20% remained stable, and 30% gained weight. The mean percent weight change by group was −4.2% (standard deviation [SD] 2.9%), +0.02% (SD 0.6%), and +5.2% (SD 5.3%), respectively. Eight‐year postoperative BMI change was −21% (lost) and −26% (stable), compared to −15% among those who gained weight preoperatively (p = 0.11). No differences in preoperative weight‐related behaviors were observed between groups.

Most adolescents preparing for MBS maintained ±5% of their baseline weight. No statistically significant differences in postoperative BMI loss or factors predicting preoperative weight change were identified.

ClinicalTrials.gov identifier: NCT00474318