Do New Weight Loss Meds Mean the End of Bariatric Surgery?
This site is intended for healthcare professionals

COMMENTARY

Do New Weight Loss Meds Mean the End of Bariatric Surgery?

Anne L. Peters, MD; Miguel A. Burch, MD

Disclosures

September 28, 2023

8

This transcript has been edited for clarity.

Anne L. Peters, MD: It's nice to meet you, Dr Burch.

It's going to be really interesting to discuss the role for bariatric surgery these days, given that we have these new, wonderful medications that help people lose weight, seemingly effortlessly, although I don't think anything is effortless.

But before I pick your brain on that, I wanted to begin with a case I just saw this morning. It's a woman whose body mass index (BMI) was around 40. She had poorly controlled type 2 diabetes. We put her on semaglutide, and she lost maybe 10 pounds. But more importantly, her diabetes just became amazingly better. Her A1c is now 7. She's come back to see us now, with her BMI at 38, and she wants to go for bariatric surgery.

What would you tell me to tell her? Would you want me to switch her to tirzepatide to see if she can get more weight loss that way? Or do you think she's a good candidate for bariatric surgery, which is what she wants? How do you decide these days about what should happen to which patients?

Miguel A. Burch, MD: Dr Peters, it's a pleasure to meet you as well.

You have opened a Pandora's box of questions, because I think that none of us are extraordinarily clear on what to do on any of these patients.

A few weeks ago, I was looking at some presentations I've given in the past 10 years. At one point in my career, I could say that the only proven durable treatment for obesity is weight loss surgery. This was in the context of patients who are morbidly obese requiring risk reduction, not for a year or two, but for decades. And I'm not talking about 10-20 pounds, but patients requiring between 40-60 pounds of weight loss.

That was a previous era; we are now in a new one. And it's wonderful, in fact, to have the opportunity to serve so many patients with something other than just surgery. That frames the context for my answer to your question, which is that we're not sure.

The National Institutes of Health (NIH) criteria for bariatric surgery had previously withstood what had been the test of time. Those criteria were determined in 1991, and the risk-benefit ratio was weighed around surgery that was then performed open. Now, the adoption of minimally invasive surgery in this country for both primary as well as revisional surgeries is greater than 97%. We are in the era of robotic surgery, which has also improved the possibility of doing minimally invasive surgery.

Looking back on those NIH criteria, they determined that any patient with a BMI ≥ 40 was at such high risk for cardiovascular disease, that even if they didn't have any disease at the time (ie, no medical diagnoses, not taking any medications on a daily basis), they were still considered candidates for weight loss surgery at that point in time. The second group of patients are those with a BMI ≥ 35 who had high-risk comorbid conditions such as cardiovascular disease, diabetes, sleep apnea, etc. We've lived under those guidelines for a long, long time.

The patient you mentioned is diabetic, with a BMI that's come down from the 40s to 38 with utilization of medications. The question is, when do you decide to consider that patient for bariatric surgery vs continued medical therapy with the glucagon-like peptide 1 (GLP-1) receptor agonists? It's a difficult question.

A lot of the decision-making has to do with patient risk. If we have a slightly different patient — for example one who's had multiple abdominal surgeries and has heart failure — they probably are a bit better served by a lower-risk option with medications. A younger patient with no surgical risk factors may be better served with an operation. This is because one of the things that we think about a lot with the medications is their long-term, cumulative cost over years. It may actually eclipse the cost of surgery eventually.

The Limitations of New Weight Loss Medications

Burch: I think that's something you could help us understand. When people are on these medications, how long do they need to be on them for? What sort of cost is associated with the medication — not only the prescription, but also the monitoring of its possible side effects?

Peters: Cost is variable. Eventually some of these, maybe all of these, will become generic. But we'll also have newer agents that give you more and more weight loss.

This is evolving in the sense that, sure, I can get weight loss with semaglutide, but that generally doesn't get me to the target. The patient isn't where they really want to be at when they've experienced the medication's maximum benefit. Tirzepatide gives you somewhat more weight loss. But even still, I have patients who clearly are never going to reach a BMI < 40 who I think really would benefit from bariatric surgery.

More than that, these drugs do reach a plateau. People can and do start out-eating them and start regaining the weight because their sense of hunger comes back. But they also need to take these medications for life. There are all sorts of disruptions as to why people can and can't get medication. I often have people who come back and say, "I ran out of my Ozempic," "There was a supply problem," or "I went on vacation and lost it." There's an inherent problem with something that you have to do every week. I think that might make the effect of the medications to some degree less durable. Yet, if someone takes them and gets to a weight that is healthy for them, I think that's probably a win-win.

My other question is, how often do you combine a GLP-1 receptor agonist in patients after they have bariatric surgery? I have patients who have had bariatric surgery and may have lost 100 pounds, but they're still not at target. This isn't to say that their target is a BMI of 20. I'm saying that with a target BMI in the mid-20s, I will add in a GLP-1 receptor agonist to help with further weight loss. Even though they do slow gastric emptying to some degree, I by and large haven't seen a problem in patients who've already had bariatric surgery. What is your feeling about that?

Identifying Patients Who Benefit From a Multidisciplinary Approach

Burch: It's a really interesting proposition. I think that we have to change the way we look at obesity management as being either surgery or medicine and start thinking about it more as a multidisciplinary approach to a chronic and potentially relapsing disease, similar to cancer. For cancer, we totally think it's normal to have surgery plus chemotherapy plus radiation plus targeted therapies. I think obesity needs to be managed more like that as well.

In terms of how we deal with patients after surgery, it's been well recognized for a long time that endogenous GLP-1 goes up fairly significantly after bariatric surgery, both sleeves and bypasses.

Part of the outcome measures of whether bariatric surgery has been successful or not are fairly well defined in the surgery literature. We expect that patients who have bariatric surgery, whether that's sleeve or bypass, would have adequate weight loss at 1 year if they've lost 50% of their extra weight. When it comes to this issue, we talk in different numbers: excess weight loss vs total body weight loss. This can be confusing. To date, we've really used excess weight loss in the bariatric surgery literature. So, 50% of your extra weight has to come off at 1 year to be considered adequate weight loss.

We can start identifying patients who are looking like they're not going to hit that number probably within 6 months of their surgery. You can think of it like a growth curve that we use in pediatrics, where we talk about what percentile the child is in, but this is in terms of patients' weight loss.

We also look at patients' weight through the year and see whether they're coming off a trajectory.

For example, we're noticing that Mrs Jones, who should have been at 50% excess weight loss by the sixth month, is only at 30%. That's an opportunity that we haven't had before. Usually it was, "Mrs Jones, you have to talk to our dietitians, you have to become more active, etc." And Mrs Jones is saying she's feeling hungry again. Until the new medications came about, there was no option for Mrs Jones. But now we work with the medical bariatrician in our practice and talk about starting medications then, with the goal of salvaging the weight loss or hitting that 50% excess weight loss before the first year.

That's one bucket of patients who I think we can work as a multidisciplinary group to ensure long-term success.

The other group of patients who can benefit are those who have had bariatric surgery and are 2, 3, 4, or 5 years out, and have now returned having gained some if not all of that weight back. For those patients, it's multifactorial why they've gained weight back. Sometimes it's the anatomy. It can be psychosocial events. But all of them together can be helped by decreasing hunger.

Those are the two buckets to think about in terms of augmentation of surgical outcomes: the patients who are heading toward inadequate weight loss within the first year, and those patients who come back after a long period of absence from the program and their weight loss can be spurred with the use of a GLP-1 receptor agonist.

Peters: I love the way you're thinking about this, because I hadn't thought about it in quite this way before.

I also hadn't thought about the notion of the trajectory of weight loss. You can tell at 6 months if someone's going to be at their goal by the end of the year. Is it really true that this is predictable?

  • 8

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.

processing....