Background: No data from randomised controlled trials of metabolic surgery for diabetes are available beyond 5 years of follow-up. We aimed to assess 10-year follow-up after surgery compared with medical therapy for the treatment of type 2 diabetes. Methods: We did a 10-year follow-up study of an open-label, single-centre (tertiary hospital in Rome, Italy), randomised controlled trial, in which patients with type 2 diabetes (baseline duration >5 years; glycated haemoglobin [HbA1c] >7·0%, and body-mass index ≥35 kg/m2) were randomly assigned (1:1:1) to medical therapy, Roux-en-Y gastric bypass (RYGB), or biliopancreatic diversion (BPD) by a computerised system. The primary endpoint of the study was diabetes remission at 2 years (HbA1c <6·5% and fasting glycaemia <5·55 mmol/L without ongoing medication for at least 1 year). In the 10-year analysis, durability of diabetes remission was analysed by intention to treat (ITT). This study is registered with ClinicalTrials.gov, NCT00888836. Findings: Between April 30, 2009, and Oct 31, 2011, of 72 patients assessed for eligibility, 60 were included. The 10-year follow-up rate was 95·0% (57 of 60). Of all patients who were surgically treated, 15 (37·5%) maintained diabetes remission throughout the 10-year period. Specifically, 10-year remission rates in the ITT population were 5·5% for medical therapy (95% CI 1·0–25·7; one participant went into remission after crossover to surgery), 50·0% for BPD (29·9–70·1), and 25·0% for RYGB (11·2–46·9; p=0·0082). 20 (58·8%) of 34 participants who were observed to be in remission at 2 years had a relapse of hyperglycaemia during the follow-up period (BPD 52·6% [95% CI 31·7–72·7]; RYGB 66·7% [41·7–84·8]). All individuals with relapse, however, maintained adequate glycaemic control at 10 years (mean HbA1c 6·7% [SD 0·2]). Participants in the RYGB and BPD groups had fewer diabetes-related complications than those in the medical therapy group (relative risk 0·07 [95% CI 0·01–0·48] for both comparisons). Serious adverse events occurred more frequently among participants in the BPD group (odds ratio [OR] for BPD vs medical therapy 2·7 [95% CI 1·3–5·6]; OR for RYGB vs medical therapy 0·7 [0·3–1·9]). Interpretation: Metabolic surgery is more effective than conventional medical therapy in the long-term control of type 2 diabetes. Clinicians and policy makers should ensure that metabolic surgery is appropriately considered in the management of patients with obesity and type 2 diabetes. Funding: Fondazione Policlinico Universitario Agostino Gemelli IRCCS.
- type 2 diabetes, Metabolic surgery,conventional medical therapy