RESUMEN
BACKGROUND: The metabolic syndrome (MS) is a complex disorder characterized by a number of cardiovascular risk factors usually associated with central fat deposition and insulin resistance. Many different medical treatments are available for MS, including bariatric surgery, which improves all risk factors. The present study aimed to evaluate, at the Clinic of Gastroenterology and Obesity Surgery (Brazil), the accuracy of different anthropometric indexes and their correlation with improvement of the MS factors in the postoperative (6-month) period. METHODS: This was a retrospective study of 140 patients who had undergone gastric bypass. Most of the patients were women (79.3%). The mean body mass index was 44.17 kg/m(2). We evaluated the weight of the subjects, the presence of diabetes mellitus and hypertension as co-morbidities, and the biochemical parameters. The anthropometric indexes tested included the percentage of excess weight loss, amount lost in kilograms, difference in the body mass index, percentage of initial weight lost, percentage of excess body mass index lost (%EBL), and percentage of initial fat mass lost. RESULTS: The %EBL had a Spearman's correlation coefficient of 0.55 (P <.0001) for the difference between the MS factors before and after Roux-en-Y gastric bypass. The receiver operating characteristic curve for the %EBL resulted in an area under the curve of 0.846 (P = 0.0001) and a sensitivity and specificity of 100% and 61.29%, respectively, for a cutoff value of 64.55%. CONCLUSION: The %EBL was the best method to report weight loss and the improvement in MS in morbidly obese subjects after Roux-en-Y gastric bypass.