Will new drugs against obesity make bariatric surgery unnecessary?

MADRID – In spirited presentations at the 2024 annual meeting of the European Association for the Study of Diabetes (EASD), Dr. Louis J. Aronne of Weill Cornell Medicine in New York City made a compelling case that the next generation of obesity drugs will make bariatric surgery obsolete. And Dr. Francesco Rubino of King's College in London, England, made an equally compelling case that this will not be the case.

Rubino even predicted that “metabolic” surgery – a new term reflecting the ability of surgery to reduce not only obesity but also other metabolic diseases in the long term – will continue and possibly even increase in the coming years.

“Medical treatment will dominate”

“Obesity treatment is the superhero of metabolic diseases because it can beat all the culprits at once, not just one, like the other treatments,” Aronne told meeting attendees. “If you treat someone's cholesterol, you're only treating their cholesterol and you may actually be increasing their risk of developing type 2 diabetes (T2D). You're treating their blood pressure, you're not treating their blood sugar, and you're not treating their lipids – the list is endless. But by treating obesity, if you lose enough weight, you can do all of those things at once.”

He pointed to the SELECT trial, which showed that treating obesity with a glucagon-like peptide-1 receptor agonist reduced major cardiovascular complications and death from any cause. These results are comparable to those of other cardiovascular disease (CVD) or lipid-lowering treatments, he said. “But we are doing much more with these drugs, including positive effects on heart failure, chronic kidney disease and a 73 percent reduction in type 2 diabetes. So we are on the verge of a major shift in the treatment of metabolic diseases.”

Aronne drew a parallel between the treatment of obesity and the historical treatment of hypertension. Years ago, he said, “we waited too long to treat people. We waited until they had severe hypertension, which in many cases was irreversible. What would you rather do for obesity today – let the patient lose weight with a drug that has been shown to reduce complications, or wait until they develop diabetes, hypertension or heart disease and then put them through surgery to treat that?”

Looking ahead, “the trend might be to treat obesity before it gets out of control,” he suggested. Treatment could begin in people with a body mass index (BMI) of 27, who would then be brought to a target BMI of 25. “That's only about a 10% change, but our goal would be to keep them in the normal range so they never go over that target. In fact, I think in a few years we'll see people with severe obesity and say, 'I can't believe someone didn't treat this guy sooner.' What will happen to bariatric surgery if nobody gets to a higher weight?”

The abundance of current weight-loss drugs and the large group on the horizon means that if someone doesn't respond to a drug, there are many other options, Aronne continued. People are referred for surgery, but perhaps only after they don't respond to medical treatment – or just the opposite. “In the United States, surgery is much cheaper, and I bet the insurance companies will force people to have surgery before they get the drugs,” he acknowledged.

A recent report from Morgan Stanley suggests that the global market for the newer weight-loss drugs could grow 15-fold over the next five years as their benefits extend beyond weight loss, and that as much as 9% of the U.S. population will be taking these drugs by 2035, Aronne said, adding that he thinks 9% is an underestimate. In contrast, the number of patients being treated in his team's surgical program has declined by about 20%.

“I think it's quite clear that medical treatment will dominate,” he concluded. “But it's also possible that the number of surgeries will increase because so many people are coming for medical therapy that we may end up having to refer more patients for surgical therapy.”

“Operations save lives”

Rubino is convinced that obesity drugs will not eliminate the need for surgery, “but it will not be business as usual,” he told the meeting attendees. “In fact, I believe these drugs will accelerate a process that is already underway – a transformation of bariatric surgery into metabolic surgery.”

“Bariatric surgery will go down in history as one of the greatest missed opportunities we have seen as a medical profession in recent years,” he said. “It is proven beyond doubt that it reduces overall mortality – in other words, it saves lives,” and it is also cost-effective and improves quality of life. Yet worldwide, less than 1% of people who meet the criteria actually undergo the surgery.

Many doctors do not inform their patients about the treatment and do not refer them for it, he said. “It would be like saying that surgery for cardiovascular disease, cancer or other important diseases is possible but is not used as much as it should.”

A key reason for the lack of procedures is that people have unrealistic expectations of diet and exercise interventions for weight loss, he said. His team's survey, presented last year at the 26th World Congress of the International Federation for the Surgery of Obesity and Metabolic Disorders, showed that 43% of respondents believed that diet and exercise were the best treatments for severe obesity (BMI > 35 kg/m²). A more recent survey asked which of several options was the most effective for weight loss. Again, a large proportion of respondents incorrectly believed that diet and exercise were the most effective—more effective than drugs or surgery—even though there is ample evidence that this is not the case.

In this context, he said, “any surgery, no matter how safe or effective, would never be very popular.” If obesity is considered a modifiable risk factor, patients might say they'll think about it for six months. In contrast, “nobody is going to tell you, 'I'll think about it,' if you tell them they need gallbladder surgery to get rid of the pain from gallstones.”

Although there are drugs to treat obesity, none of them are curative, and when they are stopped, the weight comes back, Rubino points out. “The effectiveness of drugs is measured in weeks or months, while the effectiveness of surgery is measured in decades – in the case of bariatric surgery, it's 10 to 20 years. That's why bariatric surgery will remain an option,” he said. “It not only prevents disease, but cures existing disease.”

In addition, bariatric surgery is showing value for people diagnosed with type 2D, whereas in the past it was primarily viewed as a weight-loss procedure for younger, healthier patients, he said. “In my practice, we are more likely to operate on people with type 2D, even those at higher risk for anesthesia and surgery — e.g., patients with heart failure, chronic kidney disease, dialysis — and we can still provide the same level of safety with minimally invasive laparoscopic surgery as we do with healthier patients.”

A vote at the end of the session showed that the audience was divided on the question of whether drugs would make bariatric surgery unnecessary.

“I think we have to fight it out now,” joked Aronne.

Aronne disclosed that he serves as a consultant, speaker, advisor, and receives research support from Altimmune, Amgen, AstraZeneca, Eli Lilly and Company, Intellihealth, Janssen, Novo Nordisk, Pfizer, Senda, UnitedHealth Group, Versanis, and others; he has ownership interests in ERX, Intellihealth, Jamieson, Kallyope, Skye Bioscience, Veru, and others; and he serves on the Board of Directors of ERX, Jamieson Wellness, and Intellihealth/FlyteHealth.

Rubino disclosed that he receives research and training grants from Novo Nordisk, Ethicon and Medtronic. He serves on the Scientific Advisory Board/Data Safety Advisory Board of Keyron, Morphic Medical and GT Metabolic Solutions, receives speaker honoraria from Medtronic, Ethicon, Novo Nordisk and Eli Lilly and Company, and is president of the nonprofit Metabolic Health Institute.

Marilynn Larkin, MA, is an award-winning medical writer and editor whose work has appeared in numerous publications, including Medical news from Medscape and its sister publications MDedge, The Lancet (where she served as an editor), and Reuters Health.