Nearly 40% fewer asthma attacks. That's the number researchers landed on after combing through the medical records of more than 80,000 people in the UK, and it wasn't the diabetes or weight-loss outcome they set out to measure. It showed up in patients' lungs instead.

The findings, presented this week at the European Respiratory Society Congress in Barcelona, add semaglultide, the active ingredient in Ozempic and Wegovy, to a growing list of conditions the drug appears to influence well beyond its original purpose. The research was led by Chloe Bloom, clinical associate professor in respiratory epidemiology at Imperial College London's National Heart & Lung Institute, and presented by Dr. Bohee Lee.

How the study was actually built

Bloom's team didn't run a new clinical trial. Instead, they mined UK electronic medical records to construct four parallel comparison studies, each looking at roughly 20,000 to 22,000 patients who had newly started one of four GLP-1 receptor agonist drugs, semaglutide, liraglutide, dulaglutide, or exenatide, against patients newly started on sulfonylureas, an older and unrelated class of diabetes medication. That design, known as a new-user, active-comparator analysis, is a standard way epidemiologists try to isolate a drug's real-world effect from the underlying health differences between people who get prescribed different medications.

Across those comparisons, one pattern stood out clearly: people with asthma or COPD who started a GLP-1 drug had fewer acute respiratory attacks than similar patients started on sulfonylureas. And within that group, semaglutide pulled distinctly ahead of the other three drugs.

The numbers behind the headline

"The effect was strongest with semaglutide, especially in people with asthma, where use of semaglutide appears to be associated with nearly a 40% reduction in asthma attacks," Bloom said, according to ScienceDaily's coverage of the presentation. "Semaglutide also led to a 20% reduction in COPD flare-ups."

More detailed statistics reported by HCPLive show semaglutide users had fewer respiratory exacerbations than sulfonylurea initiators overall, with an even stronger signal among patients on medium or high doses of the drug. The effect was more pronounced for asthma specifically than for COPD, though the COPD reduction still reached borderline statistical significance. Notably, liraglutide, dulaglutide, and exenatide showed no statistically significant association with reduced airway exacerbations at any dose, a detail that points toward something specific to semaglutide rather than a shared effect across every GLP-1 drug.

Why one GLP-1 drug would outperform the rest

That within-class difference is one of the more scientifically interesting parts of the finding, and the researchers don't yet have a settled explanation. GLP-1 receptor agonists are known to reduce systemic inflammation and promote weight loss, both of which independently improve respiratory symptoms in people with obesity-related asthma, so some benefit across the drug class wouldn't have been surprising. What's harder to explain is why semaglutide specifically produced a signal strong enough to reach statistical significance while its chemical cousins didn't, given that all four drugs work through variations of the same receptor pathway.

Bloom's team frames this as evidence that metabolic health and respiratory health are more tightly linked than current treatment guidelines reflect, since asthma and COPD care rarely factors in which diabetes or weight-loss medication a patient happens to be taking.

What this could mean for patients who already qualify

For the millions of people who already meet the clinical criteria for GLP-1 therapy because of obesity or type 2 diabetes, and who also live with asthma or COPD, this data suggests they may be getting a meaningful secondary benefit from a drug they're already prescribed. That's a notably different, and more immediately actionable, framing than "semaglutide might treat asthma," since it doesn't require expanding who gets the drug, only recognizing an additional benefit for people already on it.

It also reframes how physicians might think about drug choice within the GLP-1 class for patients who have both a qualifying metabolic condition and a chronic airway disease. If the difference between semaglutide and its class-mates holds up under further scrutiny, that's a genuinely useful piece of information for prescribing decisions, not just a curiosity.

The caution attached to a striking result

Bloom and her co-authors were careful to frame this as a real-world association, not proof of a causal respiratory effect. As RT reported, the researchers explicitly cautioned that patients should not be prescribed semaglutide specifically to treat lung conditions outside of current prescribing guidelines until randomized clinical trials confirm the finding. Observational data drawn from medical records, however large and carefully designed, can't fully rule out that healthier or more health-engaged patients were simply more likely to be prescribed semaglutide in the first place, a bias epidemiologists call confounding by indication.

That caveat doesn't erase the significance of the finding, it just sets the right next step. Bloom's group has already called for future metabolic therapy trials to prespecify asthma and COPD exacerbations as tracked outcomes, which would let researchers test this signal with the kind of controlled design that observational data alone can't provide. Until then, the finding stands as a genuinely promising lead rather than a new prescribing indication, one more entry in the expanding, and still not fully understood, list of things semaglutide appears to touch beyond blood sugar and body weight.