Predictors for weight loss after Roux-en-Y gastric bypass: the trend and associated factors for weight loss

Background Historically, Roux-en-Y gastric bypass (RYGB) has been considered the gold standard of bariatric surgery (BS). This procedure acts as a mixed restrictive and malabsorptive operation. Methods This retrospective cohort study included 410 morbidly obese patients (BMI > 40 kg/m(2) or BMI > 35 kg/m(2) along with at least one major comorbidity) who underwent primary laparoscopic RYGB surgery from 2009 to 2015 by a single surgery team. The patients were 18 years and older with at least 12 months of follow-up. Total weight loss (%TWL) and comorbidity resolution were compared in short-term (12 months) and mid-term (12-60 months) follow-ups. The primary and secondary outcomes were evaluating the effect of Roux-en-Y on weight loss and control of comorbidities, respectively. Results The mean +/- SD age, weight, and BMI at surgery were 40.1 +/- 10.58 years, 123.32 +/- 19.88 kg, and 45.78 +/- 5.54 kg/m(2), respectively, and 329 (80%) were female, and 62 (15%) had T2DM. %TWL was significantly higher in T2DM patients 9 months postoperatively and after that. Patients with lower BMI (< 50 kg/m(2)) at surgery and non-diabetic patients had a significantly lower %TWL over a short- and long-term follow-up (P < 0.001). Conclusions BS remains the most efficacious and durable weight loss treatment. However, a proportion of patients will experience insufficient weight loss following BS.