Metabolic effects of bariatric surgery in type 2 diabetic patients with body mass index < 35 kg/m2

Aim: The aim of this meta-analysis is to assess the metabolic effects of bariatric surgery in type 2 diabetes mellitus (T2DM) patients with body mass index (BMI) < 35 kg/m(2). Methods: We performed an electronic literature search of published articles to identify relevant evidence since inception to June 2011. Primary outcome measures were metabolic improvement and resolution diabetes after bariatric surgery. The weighted mean difference (WMD) and its 95% confidence interval (CI) were calculated from the raw data extracted from the original literature. The software Review Manager (version 4.3.1) was applied for meta-analysis. Results: Thirteen trials involving 357 patients were included in the meta-analysis. The follow-up interval ranged from 6 months to 18 years. According to WMD calculation, bariatric surgery led to 5.18 kg/m(2) of BMI lowering (95% CI, 3.79-6.57, p < 0.00001), 4.8 mmol/l of fasting plasma glucose FPG) decrement (95% CI, 3.88-5.71 mmol/l, p < 0.00001), 2.59% of HbA1c decreasing (95% CI, 2.12-3.07%, p < 0.00001), 56.67 mg/dl of triglyceride decrement 95% CI 11.53-101.82, p = 0.01) and 48.38 mg/dl of total cholesterol reduction (95% CI 21.08-75.68, p = 0.0005). Moreover, the procedures produced an increased high-density lipoprotein cholesterol by 5.37 mg/dl (95% CI-11.37-0.63, p = 0.08). However, this effect was not statistically significant. Overall, 80.0% of the patients achieved adequate glycaemic control (HbA1c < 7%) without antidiabetic medication. The surgeries produced a low incidence of major complications (3.2%) with no mortality. Conclusions: Bariatric surgery is effectual and safe in the treatment of non-severely obese BMI < 35 kg/m(2)) T2DM patients. Moreover, the metabolic benefits acquired from the procedures can be long sustained after the surgery.