The researchers, representatives of the Alliance of Randomized Trials of Medicine vs Metabolic Surgery in Type 2 Diabetes, conducted a pooled analysis of four single-center, randomised trials conducted between May 2007 and August 2013 in the United States, with observational follow-up through July 2022.

Participants were randomly assigned to receive medical/lifestyle management or one of three bariatric surgical procedures: Roux-en-Y gastric bypass, sleeve gastrectomy, or adjustable gastric banding. The primary goal was to measure the change in haemoglobin A1c (HbA1c) over a seven-year period, with data reported up to 12 years. Out of 305 eligible participants, 262 (86%) were included in the long-term follow-up.

At the seven-year mark, the medical/lifestyle group experienced a modest 0.2% decrease in HbA1c, while the bariatric surgery group demonstrated a remarkable 1.6% reduction. This trend persisted at the 12-year follow-up, with a between-group difference of −1.1%. The reduction in HbA1c was linked to a significant decrease in the use of anti-diabetes medications in the bariatric surgery group.

Additionally, diabetes remission rates were notably higher in the bariatric surgery group, with 18.2% achieving remission at seven years compared to 6.2% in the medical/lifestyle group. This gap widened further at the 12-year mark, with 12.7% remission in the surgery group compared to none in the medical/lifestyle group.

While the study demonstrated superior glycaemic control and diabetes remission in the bariatric surgery group, it also flagged specific safety concerns. Anaemia, fractures, and gastrointestinal adverse events were more prevalent in the surgery cohort, emphasising the need for meticulous monitoring and management of potential complications associated with these procedures.

The investigators concluded that these findings, in conjunction with existing evidence, endorse the use of bariatric surgery for treating type 2 diabetes in individuals with obesity.