Determinants of type 2 diabetes remission after bariatric surgery in obese Japanese patients: a retrospective cohort study

Objective Bariatric surgery (BS) improves glycemic control in type 2 diabetes; however, some patients show insufficient improvement. Understanding the pathophysiology of type 2 diabetes in obese patients can facilitate appropriate treatment for type 2 diabetes after BS. The homeostatic model assessment (HOMA) 2 enables the calculation of the values from C-peptide data and evaluation of insulin users. We aimed to evaluate the pathophysiology of type 2 diabetes using pre- and postoperative parameters and HOMA2 in obese patients who underwent BS. Methods We retrospectively reviewed data from 45 obese patients with type 2 diabetes who underwent BS. They were followed-up for 12 months. The relationship between the HOMA2 score and complete remission (CR) of type 2 diabetes after BS was analyzed. Patients with and without CR were assigned to the CR and non-CR groups, respectively. Multiple regression analysis was used to identify factors associated with improvement in type 2 diabetes after BS. Results BS significantly improved body weight and glucose metabolism. The preoperative glycosylated hemoglobin A1c level and insulin secretion (HOMA2-%B) significantly differed between the CR and non-CR groups. Postoperative weight reduction and improved insulin sensitivity correlated significantly with CR; multiple regression showed that the preoperative HOMA 2-%B independently predicted CR of type 2 diabetes after BS. Conclusion Preoperative insulin secretion, improvement in insulin sensitivity, and weight reduction after BS are related to CR of type 2 diabetes after BS. The results better reveal the pathophysiology of and treatment for type 2 diabetes in obese patients who undergo BS.