ABSTRACT
Objective To assess the effects of gastric bypass versus medical therapy in patients with obesity and type 2 diabetes. Methods The Cochrane library, Embase, PubMed, Chinese biomedical literature database and Wanfang database up to April 2014 were searched. Randomized controlled trails(RCTs) of frequently-used bariatric surgery for obese patients with type 2 diabetes were included. Study selection, data extraction, quality assessment, and data analyses were performed according to the Cochrane standards. Results Four RCTs involving 157 patients in the gastric bypass groups and 152 patients in the medical therapy group were enrolled. Compared with medical therapy, gastric bypass for type 2 diabetes significantly decreased the levels of HbA1C(mean difference = -1. 85% , 95% CI -2. 15 ~ -1. 56, P< 0. 01), fasting blood glucose( standard mean difference = - 0. 90 mmol/ L, 95% CI-1. 24 ~ -0. 57, P<0. 01), body weight(mean difference=-23. 39 kg, 95% CI -29. 17 ~ -17. 61, P<0. 01), waist circumference(mean difference= -15. 36 cm, 95% CI -17. 51 ~ -13. 22, P<0. 01) and the dose of hypoglycemic medicine; while it increased the number of patients with HbA1C<6% (RR=5. 49, 95% CI 2. 22 ~ 13. 56, P<0. 01), the rate of adverse events(RR=1. 96, 95% CI 1. 42 ~ 2. 70, P<0. 01), and the level of high-density lipoprotein-cholesterol(mean difference=1. 24 mmol/ L, 95% CI 0. 64 ~ 1. 84, P<0. 01). Conclusions Gastric bypass surgery is more effective compared with medical therapy alone for obese patients with type 2 diabetes. Further intensive RCTs of high-quality in multiple centers with long-term follow-up should be carried out to provide more reliable evidences.