Gastric Bypass Best Option for Severe Obesity With Diabetes?

Marlene Busko

February 24, 2022

Overall, Roux-en-Y gastric bypass (RYGB) was preferred when compared to sleeve gastrectomy or medical therapy in patients with severe obesity and type 2 diabetes of varying severity, an economic modeling study has found.

The study by Brianna N. Lauren, a graduate student at Columbia University, New York City, and colleagues was published online February 14 in JAMA Network Open.

"Determining which groups may benefit from a specific strategy is an important step toward personalized medicine," senior author Chin Hur, MD, MPH, professor of medicine and epidemiology at Columbia University, said in a press release from the university.

RYGB was projected to result in greater weight loss and type 2 diabetes remission when compared to sleeve gastrectomy or medical therapy in a cohort of US adults with severe obesity (body mass index [BMI] ≥ 40 kg/m2) and type 2 diabetes.

"Our study suggests that in most cases, gastric bypass is the preferred strategy when looking at a 5-year time frame, despite higher upfront surgical costs and complications, and becomes even more cost-effective when considered over 10 or 30 years," Hur said.

"We found that RYGB leads to improved health outcomes without costing a significant amount of money within the United States healthcare system for patients with severe obesity and any severity level of [type 2 diabetes]," he elaborated in an email to Medscape Medical News.

"While patients with severe [type 2 diabetes] experience less weight loss and diabetes remission after RYGB" than patients with mild or moderate type 2 diabetes, Hur added, "RYGB was still cost-effective."

"Our study does suggest that all patients with severe obesity and [type 2 diabetes] should consider RYGB over sleeve gastrectomy and medical therapy," he summarized.

Does Diabetes Severity Impact Surgery Cost-Effectiveness?

Bariatric surgery is recommended for patients with severe obesity and type 2 diabetes, but it is unclear which type of surgery is optimal or if diabetes severity impacts cost effectiveness, Lauren and colleagues write.

Currently, 85% of primary bariatric surgery performed in the United States is sleeve gastrectomy or RYGB.

Compared with sleeve gastrectomy, RYGB leads to greater 5-year weight loss (16% vs 24%) and type 2 diabetes remission (84% vs 86%), but is also associated with a higher risk of surgical complications.

While 90% of patients with mild type 2 diabetes have diabetes remission after bariatric surgery, only 2% to 12% of patients with severe type 2 diabetes have diabetes remission after bariatric surgery.

The researchers constructed a model to simulate nationally representative cohorts of US adults with severe obesity and type 2 diabetes, using 1999-2018 cycles of National Health and Nutrition Examination Survey (NHANES) data.

They simulated 1000 cohorts of 10,000 patients, of whom 16%, 56%, and 28% had mild, moderate, and severe type 2 diabetes, respectively. The simulated patients were a mean age of 55, 62% were women, and 65% were non-Hispanic White.

The model compared RYGB, sleeve gastrectomy, and medical therapy (lifestyle counseling, weight management, glucose monitoring, and drug therapies).

The researchers used the Individualized Metabolic Surgery (IMS) score developed by Aminian et al (2017) to classify an individual as having mild, moderate, or severe type 2 diabetes. "This equation considers the number of diabetes medications, insulin use, duration of [type 2 diabetes], and glycemic control (A1c) before surgical intervention," Hur explained.

The researchers input data for weight loss and regain, diabetes remission, surgical complications, survival, direct medical costs, and quality of life with these three treatments based on previous studies and databases such as STAMPEDE and the National Patient-Centered Clinical Research Network Bariatric Study.

During a 5-year period, compared with medical therapy, RYGB was associated with the most quality-adjusted life-years (QALYs) gained, a mean 0.44 QALY. The mean QALY gain was 0.59, 0.50, and 0.30 in people with mild, moderate, and severe diabetes, respectively.  

The researchers estimate that RYGB would cost $46,877 per QALY gained (where costs are in 2020 US dollars). It would cost $36,479, $37,056, and $98,940 per QALY gained in people with mild, moderate, and severe diabetes, respectively.

During the 5-year period, medical therapy cost $61,620; sleeve gastrectomy cost less than RYGB ($80,254 vs $82,253) but led to less weight loss and less diabetes remission, Hur noted.

RYGB was the preferred strategy in the overall population.

However, sleeve gastrectomy was preferred for patients with mild type 2 diabetes when the cost of RYGB was the maximum ($34,442), and for patients with severe type 2 diabetes when the cost of sleeve gastrectomy was the minimum ($13,081). Medical therapy was preferred for certain patients with severe type 2 diabetes.

The study authors were supported by grants from the National Heart, Lung, and Blood Institute and the National Institute of Diabetes and Digestive and Kidney Diseases. Lauren and Hur have reported no relevant financial relationships. A co-author reports receiving speaker and proctor fees from Intuitive Surgical, consultant fees from Johnson & Johnson and Surgical Specialties Corporation, and personal fees from C-SATS outside the submitted work.

JAMA Netw Open. 2022;5:e2148317. Full text

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