Gastric Bypass Surgery Improves Health, Lowers Costs

For people with type 2 diabetes and severe obesity, undergoing gastric bypass surgery — one of the most common forms of bariatric (weight-loss) surgery — led to greater longevity and lower medical costs over time compared with other treatment options, according to a new study published in the journal JAMA Network Open.

Gastric bypass surgery involves surgically connecting the small intestine to the upper portion of the stomach, changing the path of food and beverages to bypass most of the stomach as well as the upper part of the small intestine. Many studies have found that gastric bypass is the most effective form of bariatric surgery when it comes to both weight loss and experiencing remission of type 2 diabetes — meaning that blood glucose levels are very close to normal without taking any blood-glucose-lowering medications. There is evidence that the likelihood of experiencing diabetes remission increases with greater weight loss following bariatric surgery. Even in people who don’t experience diabetes remission, gastric bypass surgery often leads to major improvements in blood glucose control — which can substantially reduce the risk for developing diabetes complications such as retinopathy (eye disease), kidney disease, or foot ulcers (sores that don’t heal easily).

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For the latest study, researchers used a statistical model based on real-life study results to estimate various outcomes linked to gastric bypass surgery, as well as another form of bariatric surgery called sleeve gastrectomy — in which the stomach is reduced to a narrow sleeve — and standard medical therapy for diabetes. The model simulated 1,000 different groups of 10,000 people, in which 16% had mild type 2 diabetes (based on blood glucose control), 56% had moderate type 2 diabetes, and, 28% had severe type 2 diabetes before undergoing any surgery. The average age of this simulated group was about 55, and about 62% were women. The researchers were mostly interested in two different outcomes — quality-adjusted life years (QALYs), a measure of healthy longevity, and total health care costs.

Gastric bypass linked with increases longevity

Compared with standard medical therapy, gastric bypass surgery was linked to the greatest gains in healthy longevity, with an average gain of 0.44 QALYs in the overall study group. For people with mild diabetes, the average gain was 0.59 QALYs, while for those with moderate diabetes it was 0.50 QALYs, and for those with severe diabetes it was 0.30 QALYs. Based on the total health care costs associated with each method of treatment, each gain of a single QALY cost $46,877 for gastric bypass surgery, making it the most cost-effective method of treatment for the overall study group. But there was wide variation in this cost-effectiveness among people with different degrees of diabetes severity. For those with mild diabetes, the cost per QALY gained was $36,479, and for those with moderate diabetes it was $37,056. But for those with severe diabetes, the cost per QALY gained was $98,940, making the surgery barely cost-effective according to the standard of $100,000 that the researchers set at the start of their analysis.

In comparison, sleeve gastrectomy led to an average gain in 0.31 QALYs compared with standard medical treatment, as noted in an article on the study at MedPage Today. In order for sleeve gastrectomy to be more cost-effective than gastric bypass surgery, the researchers found, it would have to be offered at the minimum price used in the model — $13,081 — in someone with severe diabetes, while gastric bypass surgery would have to be offered at the highest price included in the model — $34,442 — in someone with mild diabetes.

This study is only the latest example of research showing that bariatric surgery has the greatest likelihood of leading to type 2 diabetes remission when people have less severe diabetes, or have had diabetes for a shorter duration. But according to the researchers’ calculations, it’s still likely to be cost-effective in people with more severe diabetes — and when it comes to cost-effectiveness, gastric bypass is the clear choice over other forms of bariatric surgery, such as sleeve gastrectomy, regardless of diabetes severity.

Want to learn more about bariatric surgery and type 2 diabetes? Read “Is Bariatric Surgery for You?” and “Bariatric Surgery and Diabetes: Questions and Answers.”