Association between preoperative glucose- lowering medication agents and the status of type 2 diabetes mellitus after bariatric surgery

Introduction: Bariatric surgery is an effective treatment for type 2 diabetes mellitus (T2DM) in patients with morbid obesity. This study investigates whether duration of diabetes and anti-diabetes therapy are associated with glycaemic control after surgery in a routine clinical setting. Method: A cohort analysis of a prospectively maintained database was carried out for consecutive bariatric operations performed between April 2017 and March 2018 for patients with T2DM. Results: A total 105 patients with T2DM underwent bariatric surgery (89 Roux-en-Y gastric bypass and 16 sleeve gastrectomy). Median follow-up was 19 months ([interquartile range] IQR 13-24 months). Median weight and body mass index (BMI) on the day of surgery were 125 kg (IQR 103.9- 138.7) and 42.4 kg/m2 (IQR 39-46.8), respectively. At follow- up, 68 patients (64.8%) had achieved remission of diabetes. Patients who were pre-operatively on more than one glucose-lowering medication were less likely to go into remission (odds ratio [OR] 0.13, 95% CI 0.04-0.44, p=0.001) compared to those that were on a single glucose-lowering medication agent. Pre-operative use of insulin therapy (OR 0.09, 95% CI 0.03-0.31, p=<0.001) and SGLT2 inhibitors (OR 0.23, 95% CI 0.05-0.92, p=0.038) were significant negative predictors of remission. Type of operation (p=0.34), pre-operative BMI (p=0.99), and % total weight loss (TWL) (p=0.83) did not predict remission from T2DM after surgery. Conclusions: Most patients who are medicated for T2DM can stop their glucose-lowering medication after bariatric surgery. Patients who are on multiple glucose-lowering medication agents or those dependent on insulin or SGLT2 inhibitors before bariatric surgery are less likely to undergo complete remission >12 months after bariatric surgery.