Previous research supports that type-2 diabetes in obese individuals improves following obesity surgery. However, most studies have looked at short-term effects rather than the long-term impact.

The investigators, led by Professor Geltrude Mingrone, Professor of Internal Medicine at the Universita Cattolica in Rome and a Professor of Diabetes and Nutrition at King’s College London, studied 60 obese individuals in Italy, ages 30-60 with a body-mass index (BMI) of 35 kg/m² or greater. The participants either received conventional medical treatment for type-2 diabetes (including medications and behavioral suggestions), gastric bypass or biliopancreatic diversion. During a gastric bypass a surgeon reduces the size of the stomach and re-routs the upper small intestine. In a biliopancreatic diversion a surgeon performs a more extensive small intestine bypass.

A total of 53 participants remained in the study for five years. The researchers defined improvement of diabetes as glycated hemaglobin A1c (HbA1c) concentration of 6.5% or less need for drugs for at a minimum of one year. They also measured several other standard indicators of diabetes severity.

Nineteen (50%) of the 38 people who received surgery experienced lessening (remission) of their diabetes, and none of the 15 individuals who received other treatments. Surgery lowered levels of blood glucose even in people who did not have diabetes remission, and people who received surgery took less medication. Surgery also lowered risk for cardiovascular disease and improved quality-of-life measurements.

According to Mingrone, “The lower incidence of typical diabetes complications in this study is in line with previous findings from long-term non-randomized studies; however, larger and ideally multicenter randomized trials are needed to definitively confirm that surgery can reduce diabetes morbidity and mortality compared to standard medical treatment. Nevertheless, surgery appears to dramatically reduce risk factors of cardiovascular disease.”

Professor Francesco Rubino, senior author of this study and Chair of Bariatric and Metabolic Surgery at King’s College London and a Consultant Surgeon at King’s College Hospital in London, UK concluded, “The ability of surgery to greatly reduce the need for insulin and other drugs suggests that surgical therapy is a cost-effective approach to treating type-2 diabetes.”