Preoperative Predictive Factors of Successful Weight Loss and Glycaemic Control 1 Year After Gastric Bypass for Morbid Obesity.

Background: Gastric bypass (GBP) is one of the most effective surgical procedures to treat morbid obesity and the related comorbidities. This study aimed at identifying preoperative predictors of successful weight loss and type 2 diabetes mellitus (T2DM) remission 1 year after GBP.

Methods: Prospective longitudinal study of 771 patients who underwent GBP was performed at four Italian centres between November 2011 and May 2013 with 1-year follow-up. Preoperative anthropometric, metabolic and social parameters, the surgical technique and the previous failed bariatric procedures were analyzed. Weight, the body mass index (BMI), the percentage of excess weight lost (% EWL), the percentage of excess BMI lost (% BMIL) and glycated haemoglobin (HbA1c) were recorded at follow-up.

Results: Univariate and multivariate analysis showed that BMI <50 kg/m(2) (p = 0.006) and dyslipidaemia (p = 0.05) were predictive factors of successful weight loss. Multivariate analysis of surgical technique showed significant weight loss in patients with a small gastric pouch (p < 0.001); the lengths of alimentary and biliary loops showed no statistical significance. All diabetic patients had a significant reduction of HbA1c (p < 0.001) after surgery. BMI ≥ 50 kg/m(2) (p = 0.02) and low level of preoperative HbA1c (p < 0.01) were independent risk factors of T2DM remission after surgery.

Conclusions: This study provides a useful tool for making more accurate predictions of best results in terms of weight loss and metabolic improvement.