Evaluation of preoperative and postoperative nutritional status using the CONUT score in patients undergoing sleeve gastrectomy and Roux-en-Y gastric bypass

Bariatric procedures are often followed by various degrees of nutritional imbalance, which can adversely affect postoperative recovery. The Controlling Nutritional Status (CONUT) score provides an objective laboratory-based measure of nutritional risk by integrating serum albumin, total cholesterol and peripheral lymphocyte count. The purpose of this study was to compare nutritional status before and one year after surgery using the CONUT index in individuals undergoing Sleeve Gastrectomy (SG) or Roux-en-Y Gastric Bypass (RYGB), and to determine whether the preoperative CONUT value is predictive of subsequent nutritional decline. This retrospective study comprised 393 individuals who received either SG or Roux-en-Y Gastric Bypass between January 2021 and January 2024 at a single tertiary institution. Demographic, clinical, and laboratory data (albumin, lymphocyte count, cholesterol) were recorded preoperatively and one year postoperatively. CONUT and post-minus preoperative CONUT (ΔCONUT) scores were calculated. Independent predictors of postoperative malnutrition were determined through logistic regression analysis. Of 393 patients, 235 (59.8%) underwent SG and 158 (40.2%) RYGB. Baseline demographic and laboratory parameters were comparable. At one-year, postoperative CONUT and ΔCONUT did not differ between groups (p > 0.05). In multivariable analysis, the preoperative CONUT value emerged as the sole independent predictor of postoperative nutritional decline (OR 1.41, 95% CI 1.18–1.66, p