Roux-en-Y gastric bypass versus best medical treatment for type 2 diabetes mellitus in adults with body mass index between 27 and 32 kg/m2: A 5-year randomized controlled trial

Aims: To evaluate the effects of Roux-en-Y gastric bypass (RYGB) versus best medical treatment in Asians with type 2 diabetes mellitus (T2DM) and class I obesity. Methods: In this 5-year single-centre, open-label randomized controlled trial, participants were randomized to RYGB or medical treatment including newer classes of diabetes medications (ClinicalTrials.gov:NCT02041234). The primary endpoint was diabetes remission defined as HbA1c < 6% (<42 mmol/mol) and discontinuation of glucose-lowering medication at 12 months post-intervention and beyond. Glycaemia and weight changes were assessed. Continuous glucose monitoring was performed. Results: Of 28 subjects randomized, 26 were analyzed in the final cohort (14 medical, 12 RYGB; age:44 +/- 10 years, 34.6% males, BMI:29.4 +/- 1.6 kg/m2). At 12 months, 50% of RYGB subjects achieved diabetes remission; 83% stopped all glucose-lowering medications. By year 5, 42% were in remission. None attained diabetes remission in the medical group. Percentage declines in fasting plasma glucose, HbA1c and BMI were significantly greater in the RYGB arm (all P < 0.05). Early improvements in glycaemic variability and time in range were similar in both treatment arms. Hypoglycaemia and surgical complications were observed in some RYGB subjects. Conclusions: Over 5 years, RYGB outperforms best medical treatment in glycemia and weight improvements for Asians with T2DM and class I obesity.