In a multicenter study of more than 9,700 patients in the United States who underwent bariatric surgery, those who were treated with a Roux-en-Y gastric bypass (RYGB) experienced greater weight loss, a higher diabetes remission rate, less weight regain and better long-term glycemic control than patients who had a sleeve gastrectomy (SG).

Within five years, the estimated adjusted cumulative diabetes remission rate was 86.1% for RYGB patients and 83.5% for SG—far higher than that reported for any intensive lifestyle intervention.

However, a considerable number of patients also experienced a relapse after a good outcome, particularly if they had a sleeve gastrectomy. After five years, an estimated 41.6% of sleeve gastrectomy patients relapsed compared with 33.1% of RYGB patients, for a hazard ratio of 0.75 (95% CI, 0.67-0.84).

Roux-en-Y gastric bypass

“Overall, these results indicate that RYGB is associated with better long-term T2DM [type 2 diabetes mellitus] and weight outcomes than sleeve gastrectomy in real-world clinical settings,” the authors wrote in JAMA Surgery.

The findings may be helpful to patients and physicians considering different options for bariatric surgery. In this study, people were less likely to improve if they had more severe diabetes according to the DiaRem score, a validated scoring system that predicts the probability of remission based on age, insulin use, hemoglobin A_1c and type of antidiabetic drugs used. Patients with a lower probability of diabetes remission in the DiaRem scoring system may be more likely to achieve sustainable remission with RYGB than a sleeve gastrectomy, said Anita Courcoulas, MD, a study co-author and bariatric and general surgeon at Magee-Womens Hospital at the University of Pittsburgh.

“People with more advanced diabetes at the time of surgery, for whom remission of their diabetes would be more difficult to achieve because of factors such as older age, insulin use and poor glycemic control, may expect larger improvements in their diabetes with gastric bypass,” Dr. Courcoulas said.

This finding is at odds with recent randomized clinical trials that found no significant differences in diabetes outcomes after RYGB and sleeve gastrectomy (Ann Surg 2019. [Epub ahead of print]. doi: 10.1097/SLA.0000000000003671; Obes Surg 2020;30[2]:664-672). Those trials had longer follow-up but smaller sample sizes, which may limit their power to detect differences, the authors noted.

The study was conducted at 34 U.S. health system sites in the National Patient-Centered Clinical Research Network Bariatric Study, and included 9,710 patients who underwent RYGB or sleeve gastrectomy between 2005 and 2015.

Remission was defined as any postoperative hemoglobin A_1C value less than 6.5% in a patient without a diabetes medication prescription for at least six months. Any occurrence of hemoglobin A_1C greater than 6.5% or a diabetes medication order after remission was considered a relapse.

Overall, approximately half of RYGB and one-third of sleeve gastrectomy patients had well-controlled hemoglobin A_1C levels five years after surgery.

Both groups of patients experienced considerable weight loss, but patients treated with RYGB lost more weight and had more sustained weight loss than patients who had a sleeve gastrectomy.

Limitations in the study included possible inaccuracies in electronic health record diagnostic and medication codes.

In an accompanying commentary in JAMA Surgery, Natalie Liu, MD, and Luke M. Funk, MD, MPH, of the University of Wisconsin School of Medicine and Public Health, in Madison, said Americans need improved access to bariatric surgery as a treatment for diabetes, even in cases of less severe obesity.

In the United States, less than 1% of patients with class 2 and 3 obesity undergo bariatric surgery. Even fewer patients with class 1 obesity access this surgery because they do not meet the body mass index criteria for insurance approval.

“Continued advocacy for bariatric surgery coverage, including expansion for patients with T2DM and class 1 obesity, will be critical. All patients deserve access to the most effective, evidence-based obesity and diabetes treatments,” the authors concluded.