How GLP-1 drugs compare to bariatric surgery

In the first study, which was presented at the American Society for Metabolic and Bariatric Surgery's 2024 Annual Scientific Meetings, researchers found that bariatric surgery resulted in more significant, sustained weight loss than GLP-1 drugs.

For the study, researchers conducted systematic reviews of studies published between 2020 and 2024. The studies included thousands of patients from clinical studies and several randomized clinical trials.

According to the researchers, lifestyle interventions, which include diet and exercise, resulted in an average weight loss of 7%, and people typically regained this weight within four years.

In comparison, people who received 20 weeks of weekly injections of GLP-1 semaglutide (Ozempic, Wegovy) had an average weight loss of 10%, and people who received 36 weeks of weekly injections of tirzepatide (Mounjaro, Zepbound) had an average weight loss of 21%. However, about half of the weight returned once treatment was stopped for both drugs. If treatment continued, patients reached a weight-loss plateau of 22% for tirzepatide and around 15% for semaglutide after 17 to 18 months.

Overall, bariatric surgery, including gastric bypass and sleeve gastrectomy, resulted in the most weight loss for patients after one year at 32% and 29%, respectively. Patients who received bariatric surgery also maintained a weight loss of around 25% up to 10 years after surgery.

In a separate study presented at the American College of Surgeons Clinical Congress 2024, researchers from Northwestern University found that bariatric surgery was more cost-effective than GLP-1 drugs over the long term despite having higher upfront costs.

Using data from thousands of patients from different clinical trials, the researchers predicted the costs of GLP-1 drugs and bariatric surgery until death (up to 50 years). A treatment was only considered to be cost-effective if the total cost was less than 100,000 per quality-adjusted life year (QALY).

Overall, the estimated cost of bariatric surgery ranged between $17,4000 to $22,850, which was higher than the average year cost of $9,360 to $16,2000 for GLP-1 drugs. However, bariatric surgery added approximately two QALYs and would save a patient more than $9,000 to earn a QALY.

Combining GLP-1 drugs with bariatric surgery would save more than $7,200 per QALY compared to surgery alone. It would also add more than five QALYs.

"Undergoing bariatric surgery is more cost effective in the long run than maintaining these medications for the remainder of an individual's life," said Joseph Sanchez, a general surgery resident at Northwestern Medicine and the study's lead author. "The critical role for these medications from a cost-effectiveness perspective is to use these medications to address weight regained after bariatric surgery."

According to Sanchez, these findings could change if the cost of GLP-1 drugs decrease or if new, lower-priced weight loss medications become available, but the cost would have to decrease by almost 75%.

Commentary

According to Mir Ali, a bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center, "[m]etabolic and bariatric surgery are the most effective and durable treatment for obesity."

"Diet and exercise are only effective for 1 to 2 percent of people who are obese," Ali said. "Not only is it the most effective for weight loss, but it is also the most effective for sustaining weight loss. Surgery is very underutilized, with only about 1 to 2 percent of people who could benefit from it getting the surgery. These surgeries have long-term benefits with remissions lasting 15 years or more."

Mitchell Roslin, chief of bariatric surgery at Northwell Lenox Hill Hospital, agreed with Ali, saying that the results of bariatric surgery "are lasting as the control mechanism is part of you."

"In comparison, the GLP medicines have half as much weight loss in diabetics, as those without," Roslin said. "Stated differently, these medications have been approved for diabetes for approximately 10 years. Numbers have only increased and few have had lasting weight loss similar to these studies."

When it comes to cost-effectiveness, Sanchez noted that patients must use GLP-1 drugs indefinitely to maintain their weight loss.

"GLP-1 RA are lifelong medications for obesity management that are not always covered by insurance and can cost some people $800 to $1,200 per month out-of-pocket," Sanchez said.

"As evidence of health benefits of GLP-1 RA [drugs] continues to come out, insurance companies will have to decide whether they will cover these medications and in which case scenarios," said Anne Stey, an assistant professor of surgery at Northwestern University Feinberg School of Medicine and the senior investigator on the cost-effectiveness study. "Understanding if and how these different obesity management options are cost effective is critical to ensure as many people have access to these medications as possible."

Advisory Board's weight-related resources

To help address the growing weight-related issues in healthcare, Advisory Board offers several resources on different topics, including:

GLP-1 drugs

Radio Advisory's Rachel Woods has covered GLP-1 drugs on the podcast, discussing the potential future of these drugs and how they could help — or hurt —  health systems' finances.

Other useful resources include the expert insights  "5 catalysts that will impact the future of weight management drugs,"  and  "What the headlines get wrong about weight management medications."

Bariatric surgery

In 2022, the American Society for Metabolic and Bariatric Surgery and the International Federation for the Surgery of Obesity and Metabolic Disorders updated guidelines for weight-loss surgery, expanding eligibility for more people.

Under the new guidelines, anyone with a BMI over 35, regardless of their health status, is eligible for weight-loss surgery. People with a BMI over 30, which is the official definition of obesity, are also eligible if they haven't been able to achieve substantial or long-term weight loss.

This expert insight outlines three barriers to bariatric surgery and how to overcome them. For patients considering bariatric surgery, this resource offers three factors they should keep in mind while they decide.

Meanwhile, this expert insight describes four ways hospital and health system leaders can use comprehensive obesity care to boost surgical services. This Daily Briefing story also covers how health insurers are working to incentivize bariatric surgery.

Healthcare's approach to obesity

Recently, healthcare organizations have made an effort to move away from using BMI to determine obesity and assess health. Last June, the American Medical Association voted to adopt a new policy that moves away from using BMI alone when assessing whether a patient is at a healthy weight.

Some physicians are also choosing to take a "weight-neutral" approach when they assess their patients' health and recommend treatments.

In a Radio Advisory episode, Rachel Woods and Advisory Board experts Darby Sullivan and Chloe Bakst discuss healthcare's current approach to obesity and whether it's helping or harming patients. Another episode also discusses what comprehensive weight management should look like.

Separately, this expert insight covers three missteps in our current approach to obesity, outlining five potential ways providers can address these issues. (Reed, Axios, 10/21 [1]; Bailey, Medical News Today, 6/11; American College of Surgeons, EurekAlert!, 10/18; Twenter, Becker's Hospital Review, 10/17; Reed, Axios, 10/21 [2])