Endocrine Abstracts

Objective: Bariatric surgery has a marked effect on diabetes risk in the obese. The aim of this study was to evaluate weight-loss independent effects of gastric bypass on glucose and insulin levels over 10-years of follow-up.

Research design and methods: A total of 2010 obese individuals received bariatric surgery in the Swedish Obese Subjects (SOS) study (376 patients underwent non-adjustable or adjustable banding, 1369 underwent vertical banded gastroplasty (VBG), and 265 underwent gastric bypass (GBP)). Health examinations with anthropometric measurements and laboratory analyses were conducted at baseline and at 2- and 10-year follow-up. Follow-up rates were 92% and 74% at 2- and 10-years, respectively. Diabetes was defined by fasting venous whole blood glucose 6.1 mmol/litre or more, and/or self-reported diabetes medication. Weight loss was categorized in four groups: <30 kg; 30 to 25 kg; 25 to 20 kg; 20 to 15 kg. Changes in blood glucose and serum insulin levels were compared between the three surgical groups accounting for the degree of weight loss. Data was analysed separately for persons with and without diabetes at baseline.

Results: The average 10-year weight losses were 18 kg, 20 kg and 29 kg in the banding, VBG and GBP groups, respectively (P<0.001). Changes in fasting glucose and insulin were related to the degree of weight loss. There were no significant differences in changes in glucose and insulin between the three surgical groups, when patients within same weight loss categories were compared. This was observed for patients with and without diabetes at baseline. As expected, changes in glucose and insulin levels were more marked in patients with diabetes at baseline as compared to persons without.

Conclusions: Given same degree of weight loss over 10-years following bariatric surgery, there was no support for weight-loss independent benefits of GBP over banding and VBG on fasting glucose and insulin levels.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.