E302: Do GLP-1 drugs reduce overall healthcare spending?

For many people, the FDA-approved drug class called GLP-1s has been a game changer for managing type 2 diabetes and weight loss. An estimated one in eight US adults is using this type of drug, which mimics a natural gut hormone to regulate blood sugar, slow stomach emptying, and suppress appetite. Researchers and the public have been scrutinizing the pros and cons of taking these drugs for many years. One critical question that remains is does the use of GLP-1s translate into lower medical expenses for consumers, healthcare providers, insurance companies, and the government? Today, we're speaking with Duke University health economist Jonathan Zhang on the answer to these questions from his multi-year study of veterans who use GLP-1s. The results are surprising. Interview Summary Jonathan, first, let's talk broadly. Would you briefly describe the kinds of health benefits people are experiencing with GLP-1s, particularly in terms of changes in behavior and overall health? Yes. So GLP-1s are medications that manage body weight and improve metabolic health. The primary health benefits are via better blood sugar regulation and weight loss via reducing appetite. But there's larger health benefits that are much broader. So, trials have also shown that they lower blood pressure, reduce strokes and heart attacks, among other cardiovascular benefits. Overall also improves, so things like obstructive sleep apnea, improvements in inflammation-related measures. And recently it was FDA approved to treat MASH, which is a form of fatty liver disease. Finally, people also report feeling less hungry. They get full faster, fewer cravings, and reduction in what is often called food noise, which can potentially help people make a range of better behavior decisions and changes relating to food and perhaps even beyond food. However, the evidence on that seems to be promising, but new and less strong. Thank you for sharing those. I know a lot of our listeners have heard some of those issues and some of those points about how GLP-1s could change the way we behave, and some of the health outcomes. So, let's dig into your particular study. In your working paper for the National Bureau of Economic Research (NBER) you and your co-authors describe a natural experiment involving patients and doctors in the Department of Veteran Affairs, and their access to and use of GLP-1s. Would you lay out the general parameters of your study for our listeners? Yes, absolutely. So, like many medications, what we know about GLP-1s primarily comes from randomized controlled trials, which have small sample sizes and often select for quite sick patients. As GLP-1s reach a broader population, the population becomes less pro-comparable to those in trials, so the real-world impacts become less obvious. Moreover, there are some outcomes such as healthcare utilization or spending costs that are incredibly important for policy but not directly studied in trials. We were interested in studying in a very large healthcare system, that is the VA, the Veterans Health Administration, the real-world impacts of GLP-1s using readily collected data from the healthcare system and a quasi-experiment. So that is we try to emulate a real experiment where some patients get GLP-1s from their primary care doctor and others do not. And the reason one patient might get it while the other doesn't is because their doctors differ in their likelihood or propensity to prescribe these drugs. And we focus on the Veterans Health Administration, the VHA, because the veteran population is quite diverse, at least in terms of comorbidities relative to the trials per se and also in age, say, compared to Medicare. And GLP-1s are provided in the VA to eligible patients at a pretty affordable cost. So, sort of a nice policy playground for us to think about what outcomes might look like when GLP-1s become readily available and affordable to all Americans. Great. Thank you for sharing that because now we have a good sense of the quasi experiment that you all were able to exploit. That there were providers who had a high tendency to prescribe GLP-1s versus those who didn't. And looking at that difference, you were able to see how GLP-1s may have affected the outcomes that you were interested in. So now tell u