Study shows bariatric surgery provides superior long-term treatment for type 2 diabetes in patients with obesity

Tuesday, February 27, 2024, CLEVELAND: Research by Cleveland Clinic and three other U.S. medical centers has found that bariatric surgery provides better long-term control of blood glucose levels in patients with obesity and type 2 diabetes, compared with medical therapy.  

Study participants who had bariatric surgery also experienced higher rates of complete diabetes remission up to 12 years after their surgical procedure. 

The research was published in JAMA. 

The Alliance of Randomized trials of Medicine vs Metabolic Surgery in Type 2 Diabetes (ARMMS-T2D) consortium analyzed long-term results of four randomized trials that were conducted at four U.S. centers: Cleveland Clinic (Ohio), Joslin Diabetes Center/Brigham and Women’s Hospital (Massachusetts), University of Pittsburgh (Pennsylvania), and University of Washington/Kaiser Permanente Washington (Washington). About half of the ARMMS-T2D study participants were from Cleveland Clinic.  

Ali Aminian, M.D., a co-investigator of the ARMMS-T2D study and the director of Cleveland Clinic’s Bariatric & Metabolic Institute, said: “ARMMS-T2D provides the largest analysis with the longest follow-up in the setting of randomized clinical trial to compare bariatric surgery with medical therapy for the treatment of type 2 diabetes in patients with obesity.” 

According to the Centers for Disease Control and Prevention, about 1 in 10 Americans have diabetes and approximately 90% of the diabetes cases in the USA are type 2 diabetes. The chronic condition happens when an individual has persistently high blood sugar levels. Without treatment, type 2 diabetes can cause various health problems, like heart disease, kidney disease, and stroke.  

For the ARMMS-T2D, 262 eligible participants were enrolled between 2007 and 2013 and followed until 2022. The medical group included 96 participants and the surgical groups had 166 participants. Patients in the medical group received a variety of medications for the treatment of type 2 diabetes, including FDA-approved incretin/GLP-1 agonists. Those medications help lower blood sugar levels and promote weight loss. Bariatric surgery included gastric bypass, gastric sleeve, and adjustable gastric banding. The average age was 50; 68% of the participants were female; and 67% were white. The average body mass index (BMI) was 36.4.  

Researchers reported the change in blood sugar levels – measured in this study as HbA1c level – immediately after surgery up to 12 years. HbA1c is a standard laboratory test that reflects average blood sugar over the past three months. Between the surgical group and the medical therapy group, researchers noted a large difference in HbA1c of 1.4% at seven years and 1.1% at 12 years with bariatric surgery providing superior blood glucose control.    

Researchers also looked at diabetes remission over time (defined in this study as a HbA1c level less than 6.5% without need for diabetes medications for at least 3 months). In the bariatric surgery group, 50.8% of the participants achieved remission of diabetes at one year, compared with 0.5% of participants in the medical group. At seven years, 18.2% of the participants in the bariatric surgery group still had remission of their diabetes. 

Dr. Aminian said: “The magnitude of benefits of bariatric surgery is very large and durable. Patients with diabetes usually need more medications over time to control their blood glucose. However, a two-hour surgery could help many of them to control their diabetes without needing any medications, including insulin.” 

• Study results showed 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. 

• The use of insulin after bariatric surgery was also significantly lower (16%) than in the medical group (56%) at seven years.  

• The use of incretin/GLP-1 agonist medications was greater in the medical group across all annual visits. 

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

In the bariatric surgery group, anemia, fractures, and gastrointestinal symptoms were more common. Dr. Aminian said it is important for patients to be treated by a multidisciplinary team, including nutrition specialists, so that the necessary vitamins and supplements can be recommended after bariatric surgery.  

Bartolome Burguera, M.D., Ph.D., an endocrinologist and Chief of the Medical Specialty Institute at Cleveland Clinic, said: “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 recently 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.” 

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 underwent bariatric surgery after a few years. Researchers accounted for that change in their analysis.  

ARMMS-T2D is supported by cooperative agreement U01 DK114156 from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). 

About Cleveland Clinic  

Cleveland Clinic is a nonprofit multispecialty academic medical center that integrates clinical and hospital care with research and education. Located in Cleveland, Ohio, it was founded in 1921 by four renowned physicians with a vision of providing outstanding patient care based upon the principles of cooperation, compassion and innovation. Cleveland Clinic has pioneered many medical breakthroughs, including coronary artery bypass surgery and the first face transplant in the United States. Cleveland Clinic is consistently recognized in the U.S. and throughout the world for its expertise and care. Among Cleveland Clinic’s 77,000 employees worldwide are more than 5,658 salaried physicians and researchers, and 19,000 registered nurses and advanced practice providers, representing 140 medical specialties and subspecialties. Cleveland Clinic is a 6,699-bed health system that includes a 173-acre main campus near downtown Cleveland, 23 hospitals, more than 275 outpatient facilities, including locations in northeast Ohio; southeast Florida; Las Vegas, Nevada; Toronto, Canada; Abu Dhabi, UAE; and London, England. In 2022, there were 12.8 million outpatient encounters, 303,000 hospital admissions and observations, and 270,000 surgeries and procedures throughout Cleveland Clinic’s health system. Patients came for treatment from every state and 185 countries. Visit us at clevelandclinic.org. Follow us at twitter.com/ClevelandClinic. News and resources available at newsroom.clevelandclinic.org.  

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