LAUSR

This study aimed to evaluate the effectiveness of only Roux-en-Y gastric bypass (RYGB) in patients with type 2 diabetes (T2D) and body mass index (BMI) of 30–40 kg/m2. A literature search was performed on MEDLINE, Embase, and Cochrane CENTRAL. The searches were performed in February 2017. English was the target language of the publications. The PICO question was used to determine eligibility for studies to be included: population, patient with BMI 30–40 kg/m2; intervention, RYGB; comparison, control group with medical care alone; and outcome, metabolic outcomes. Only randomized clinical trials (RCT) were selected. The main outcome was T2D remission. Secondary outcomes were metabolic effect of RYGB, such as hypertension and dyslipidemia. A total of five RCTs were included. The studies included a larger proportion of women, and the average time of T2D duration ranged between 6 and 10 years with 43.3% of the patients having a BMI below 35 kg/m2. Despite randomization, the baseline demographics such as age, HbA1c, and duration of diabetes were often less favorable in the surgical group. At the longest follow-up, RYGB significantly improves total and partial type 2 remission, OR 17.48 (95% CI 4.28–71.35) and OR 20.71 (95% CI 5.16–83.12), respectively. HbA1c also reduces at longest follow-up in the surgery group (− 1.83 (95% CI − 2.14; − 1.51)). All these three outcomes revealed high level of evidence according to GRADE evaluation. There is already strong evidence that RYGB improves metabolic outcomes for at least 5 years in patients with class I obesity.