Metabolic Syndrome Modifies Changes in Body Composition After Sleeve Gastrectomy: A Quantitative CT Study

Objective: To investigate changes in body mass index (BMI), body composition, and laboratory indicators in obese patients with different metabolic status after laparoscopic sleeve gastrectomy (LSG). Methods: This prospective study included 52 obese patients who underwent LSG. Clinical and quantitative CT-based body composition data were collected preoperatively and at the 12-month follow-up. Patients were categorized into metabolic syndrome (MS) and non-MS groups. Changes in BMI, body composition, and laboratory indicators after LSG were compared between groups, and the correlations between body composition and clinical indicators-at both baseline and postoperatively-were analyzed, stratified by MS status. Results: Among 52 obese patients undergoing LSG, 24 (46%) had MS. All patients exhibited significant postoperative improvements in body weight, laboratory parameters, and body composition. The postoperative visceral fat area showed the greatest improvement ratio [non-MS: 0.62 (0.48, 0.70); MS: 0.60 (0.49, 0.67)] among abdominal fat compartments compared to preoperative levels, while liver fat (LF) demonstrated the most marked improvement [non-MS: 0.53 (0.24, 0.60); MS: 0.55 (0.28, 0.66)] among ectopic fat deposits. However, reductions in BMI (P = 0.036) and postvertebral muscle fat content (P = 0.041) were greater in the non-MS group. At the 12-month follow-up, changes in LF positively correlated with changes in blood glucose (r = 0.414, P = 0.044) in the MS group, whereas changes in BMI correlated with changes in triglyceride (r = 0.427, P = 0.023) and low-density lipoprotein (r = 0.480, P = 0.01) in the non-MS group. Conclusion: LSG significantly improves body composition and metabolic parameters in obese patients. The correlations between body composition and laboratory indicators, both at baseline and in their postoperative changes, differed according to metabolic status. These findings suggest that a comprehensive assessment of body composition and metabolic markers in patients undergoing bariatric surgery enables targeted interventions against the key risk factors associated with distinct metabolic phenotypes.