Incidence and Predictors of Suboptimal Early Weight Loss after Bariatric Procedures

Bariatric surgery is the most effective intervention for obesity, but suboptimal early weight loss remains common and challenging to manage. Identifying predictors of early inadequate weight loss is increasingly relevant as glucagon-like peptide-1 (GLP1) therapies emerge as adjunctive treatments.

We conducted a retrospective cohort study of 166,843 patients with BMI > 30 kg/m² and complete six-month follow-up data from the 2023 MBSAQIP registry. Suboptimal weight loss was defined as < 10% total weight loss (TWL) at six months. Predictors of suboptimal weight loss were assessed using LASSO logistic regression, random forest, and gradient boosting models, considering demographic, clinical, and procedural variables. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC).

Overall, 12.6% of patients experienced suboptimal weight loss. Incidence was lower for primary surgical procedures (7-13%) compared with endoscopic interventions (34-50%). Across all models, consistent predictors of suboptimal weight loss included female sex, higher baseline BMI, older age, diabetes, and black race. Predictive performance of clinical variables alone was modest (AUROC 0.57-0.60), indicating substantial unexplained variability.

Suboptimal early weight loss is common and varies widely between procedures. Baseline demographics and comorbidities can guide preoperative counseling, but additional behavioral, socioeconomic, and genetic factors may be required to improve prediction and guide individualized interventions, including early GLP1 therapy.