Study Findings Support Bariatric Surgery as a Superior Treatment Option to Medical Management for Type 2 Diabetes

Type 2 diabetes (T2D) continues to affect a large percentage of the global population, and about 1 in 10 Americans have diabetes. Several studies have indicated that bariatric surgery is superior to lifestyle modification and medical therapies for diabetes treatment. But these studies have been limited by a variety of factors including small sample sizes, single-site studies, obesity severity, surgery types and follow-up duration. As a result, many providers refrain from recommending bariatric surgery unless the patient has a body mass index (BMI) greater than 35 kg/m² or higher. Yet, fewer than 1% of patients with BMI of 35 kg/m² or higher consider or pursue surgical treatment. Additionally, medications to treat these patients remain costly and do not yet have proven long-term efficacy.

A recent study published in JAMA looked at the long-term durability of glycemic control and safety of bariatric surgery compared with medical/lifestyle management of T2D. The Alliance of Randomized Trials of Medicine vs Metabolic Surgery in Type 2 Diabetes (ARMMS-T2D) consortium pooled together data from four U.S. single-center randomized trials, which to the authors’ knowledge represents the largest analysis in the randomized setting with the longest follow-up to date.

The four included trials were: Cleveland Clinic (Ohio, STAMPEDE), Joslin Diabetes Center/Brigham and Women’s Hospital (Massachusetts, SLIMM-T2D), University of Pittsburgh (Pennsylvania, 127 TRIABETES) and University of Washington/Kaiser Permanente Washington (Washington, CROSSROADS). About half of the ARMMS-T2D data came from Cleveland Clinic.

“In the STAMPEDE Trial, we reported data at five years and found that bariatric surgery is more effective and durable than medical and lifestyle intervention for treatment of T2D,” explains Ali Aminian, MD, Director of Bariatric and Metabolic Institute at the Cleveland Clinic, Professor of Surgery at the Cleveland Clinic Lerner College of Medicine and an author on the study. “This was true even in those with a BMI of 27.0 to 35 kg/m². We wanted to expand our knowledge in this area. In the ARMMS-T2D, we reported our long-term follow-up findings from our participants up to 12 years post-randomization.”

Study design

Between 2007 and 2013, 262 eligible participants were enrolled in the study and followed until 2022. The medical group included 96 participants and the surgical groups had 166 participants. Mean (SD) age was 49.9 (8.3) years, 68.3% were female and 67.2% were white. Mean (SD) BMI was 36.4 (3.5) kg/m² and 96 (36.6%) participants had baseline BMI less than 35 kg/m². Mean (SD) hemoglobin A1C (HbA1c) level was 8.5% 190 (1.5%), and median follow-up was 11 years (range: 7-15).

Patients in the medical group were treated with a variety of medications for the treatment of Type 2 diabetes, including FDA-approved incretin/GLP-1 agonists. Patients in the surgery cohort underwent bariatric surgery (gastric bypass, gastric sleeve and adjustable gastric banding).

Despite higher baseline values, the bariatric surgery group had significantly lower HbA1c levels than the medical/ lifestyle group at all points after baseline (P < .001). At 7 years, mean HbA1c decreased to 8.0% from a baseline of 8.2% (difference, 0.2% [95% CI, −0.5% to 0.2%]) in the medical/lifestyle group and from 8.7% to 7.2% (difference, 1.6% [95% CI, −1.8% to −1.3%]) in the bariatric surgery group. The between-group difference was −1.4% (95%CI, −1.8% to −1.0%; P < .001) at 7 years and −1.1% (95% CI, −1.7% to −0.5%; P = .002) at 12 years.

At year 7, there were no significant differences in the improvements in mean HbA1c from baseline between Roux-en-Y gastric bypass (difference, −1.7% [95% CI, −2.0% to −1.3%]) and sleeve gastrectomy (difference, −2.0% [95% CI, −2.6% to −1.5%]); HbA1c improvement after adjustable gastric banding (0.8% [95%CI, −1.3%to −0.2%]) was less than for sleeve gastrectomy (P = .007) and Roux-en-Y gastric bypass (P = .03).

During the ARMMS-T2D follow-up, 25% of the study participants that were in the medical group did not want to continue with that treatment and chose to undergo bariatric surgery after a few years. Dr. Aminian notes that the researchers accounted for that change in their analysis.

Diabetes remission

In the medical/lifestyle group, 0.5% of participants achieved remission of diabetes at one year compared with 50.8% in the bariatric surgery group. While the percentage of achieving remission decreased over time in the bariatric surgery group, remission rates remained higher than the medication/lifestyle group.

At year 7, remission was 6.2% in the medical/lifestyle group compared with 18.2% in the bariatric surgery group (odds ratio, 3.4 [95% CI, 1.3-9.2]; P = .02), with the difference remaining statistically significant at 12 years (P < .001). Rates of remission were 24.5% in the Roux-en-Y gastric bypass subgroup, 15.2% in the sleeve gastrectomy group, and 8.9% in the adjustable gastric banding group.

“The concept of remission in this context is important,” says Dr. Aminian. “Patients are managing this chronic disease by taking medications like insulin, which has become incredibly costly. With a two-hour procedure, we can help many patients get off insulin and help them manage diabetes without being reliant on any diabetes medications.”

The study reports that 40% of patients in the bariatric surgery group and only 4% of patients in the medical group were off diabetes medications at seven years. Insulin usage after bariatric surgery was also significantly lower (16%) in the surgery group than in the medical group (56%) at seven years. The medical group had higher usage rates of incretin/GLP-1 agonist medications across all annual visits.

In terms of changes in weight over time, the researchers noted 19.9% weight loss in the surgical group, compared to 8.3% weight loss in the medical group at the seven-year follow-up. At 12 years, the bariatric surgery group continued to have superior weight loss (19.3%) compared to the medical group (10.8%).

Bartolome Burguera, MD, PhD, an endocrinologist and Chief of the Medical Specialty Institute at Cleveland Clinic, says “Type 2 diabetes and obesity are chronic diseases that need long-term treatment. This study shows that bariatric surgery provides long-term benefits for the treatment of Type 2 diabetes in many patients with obesity. We now have FDA-approved medications for the treatment of Type 2 diabetes – such as semaglutide and tirzepatide – but access to those medications needs to be improved. I think it’s important to discuss with our patients all the available treatment options for Type 2 diabetes and obesity so that we can identify the best long-term therapy for each patient.”

Care at Cleveland Clinic

Dr. Aminian recognizes that most patients prefer to try the least invasive approach first, but it’s still important to consider every available option. “Patients will start with lifestyle modification first,” he explains. “If that doesn’t work, they’ll go on medication, and if that still doesn’t work, then they’ll consider surgery. Clinicians will often go along with this ‘step-up approach.’ But the problem is that sometimes clinicians forget about the surgery option, and they keep adding more and more medications. Meanwhile, the patient still isn’t seeing an improvement.”

He continues, “At Cleveland Clinic, we take a multidisciplinary approach to treatment, so we work very closely with our colleagues in other disciplines. We discuss and track each patient’s progress. We know that if the patients don’t see results, they’re going to get frustrated. We don’t want to miss out on helping our patients because they feel hopeless, and we believe that bariatric surgery can help these patients see improvement and help restore that hope.”