Bariatric surgery improves long-term diabetes outcomes more than medication, lifestyle interventions

Patients who underwent bariatric surgery for type 2 diabetes had remission rates of 18.2% at seven years and 12.7% at 12 years, compared to 6.2% and 0%, respectively, in patients treated with medical and lifestyle interventions, a new review found.

Patients with type 2 diabetes who underwent bariatric surgery had superior glycemic control, used less diabetes medication, and had higher rates of remission seven to 12 years later versus patients who managed their diabetes with medication and lifestyle changes, new study results show.

Researchers compared outcomes of four U.S. single-center randomized trials carried out between May 2007 and August 2013. Observational follow-up continued through July 2022, for a median of 11 years. A total of 96 patients underwent medical/lifestyle interventions modeled after the Diabetes Prevention Program and Look AHEAD trials, and 166 had Roux-en-Y gastric bypass, sleeve gastrectomy, or adjustable gastric banding surgery. One quarter of patients originally randomized to lifestyle/medical management underwent bariatric surgery during the follow-up period. Patients had an average age of 49.9 years, 68.3% were women, and 31% were Black. At baseline, 36.6% of patients had a body mass index less than 35 kg/m2 and their average HbA1c level was 8.5%. Findings were published by JAMA on Feb 27.

At seven years, the bariatric surgery group's HbA1c decreased by 1.6% from a baseline of 8.7% (95% CI, −1.8% to −1.3%) compared with a decrease of 0.2% from a baseline of 8.2% (95% CI, −0.5% to 0.2%) in the medical/lifestyle group, for a between-group difference of −1.4% (95% CI, −1.8% to −1.0%; P<0.001). At 12 years, the between-group difference in HbA1c level was −1.1% (95% CI, −1.7% to −0.5%; P=0.002). Rates of diabetes medication use did not change over time in the medical/lifestyle group but fell from 97.6% (162 of 166) at baseline to 38.0% (62 of 163) after one year in the bariatric surgery group. Rates remained significantly lower during follow-up.

At seven years, diabetes remission was greater in the surgery group (6.2% vs. 18.2%; P=0.02) and remained greater at 12 years (0.0% in the medical/lifestyle group vs. 12.7% in the bariatric surgery group; P<0.001). Bariatric surgery was also more effective in improving HDL cholesterol and triglyceride levels at seven and 12 years compared with lifestyle/medical management. There were two deaths in each group during the follow-up period and no differences in major cardiovascular events. Patients who underwent surgery did have an increased risk of nutritional deficiencies, gastrointestinal adverse events, and bone fractures.

To the authors' knowledge, this is the largest pooled analysis on this topic with the longest follow-up to date. One limitation is that all included studies were open label. In addition, treatments examined in the trials were not identical and randomization ratios were not all 1:1. "These results combined with existing evidence support the use of bariatric surgery for treatment of type 2 diabetes in people with obesity," the authors wrote.