Is All Weight Loss Equal Following Sleeve Gastrectomy? Defining Body Composition and Anthropometric Thresholds for Hyperglycemia Remission in Women from a Prospective Cohort Study

Adiposity magnitude and distribution strongly influence the risk of prediabetes and type 2 diabetes (T2D). While metabolic bariatric surgery provides durable weight loss and metabolic improvement, optimal anthropometric and body composition targets for hyperglycemia remission remain undefined. We conducted a prospective cohort study of women undergoing sleeve gastrectomy (SG) in Melbourne, Australia (2019–2022). Anthropometric, biochemical, and dual-energy X-ray absorptiometry (DXA) derived body composition data were collected at baseline and 12 months post-surgery. The primary outcome was change in body composition. Secondary outcomes included percentage total body weight loss (%TBWL), fat-mass loss, and central adiposity thresholds associated with hyperglycemia remission, defined as HbA1c < 6.0% or fasting glucose < 6.0 mmol/L without medications. Of 50 patients recruited, 39 completed the study. Marked reductions in fat mass and central adiposity were observed. All seven participants with T2D achieved hyperglycemia remission; five discontinued hypoglycemic therapy. Among those with prediabetes/T2D (n = 14), 93% achieved hyperglycemia remission. ROC analyses identified candidate thresholds associated with remission, including ≥ 21.9% TBWL (AUC 0.85), ≥ 75.8% fat-mass contribution to weight loss (AUC 0.85), postoperative waist circumference ≤ 107 cm (AUC 0.93), and waist-to-height ratio ≤ 0.72 (AUC 0.85). Logistic regression combining %TBWL and WHtR yielded an AUC of 1.00; however, this likely reflects overfitting given the very small remission subgroup. Total weight loss and reductions in central adiposity were strongly associated with hyperglycemia remission after SG in women. Achieving 20–25% TBWL, ≥ 75% fat-mass contribution to weight loss, and postoperative waist circumference < 107 cm may represent candidate treatment targets, but require validation in larger independent cohorts. Reductions in central adiposity were more strongly associated with hyperglycemia remission than BMI-based measures alone. Hyperglycemia remission was common, with 93% of participants with prediabetes or T2D achieving this. Postoperative thresholds of ≥ 21.9% TBWL, ≥ 75.8% fat mass loss, waist circumference ≤ 107 cm and waist-to-height ratio ≤ 0.72 were strongly associated with hyperglycemia remission. These exploratory thresholds may help guide postoperative monitoring but require validation in larger, independent cohorts.