People with asthma who started semaglutide had close to 40 percent fewer asthma attacks than similar patients started on an older diabetes drug, according to an analysis of United Kingdom electronic health records presented in Barcelona. The same work found a 20 percent reduction in COPD flare-ups.
The design is the most important thing to understand about the number. This was not a randomized trial. Researchers led by Professor Chloe Bloom, clinical associate professor in respiratory epidemiology at the National Heart and Lung Institute, Imperial College London, ran four parallel studies using routine medical records, each covering between 20,000 and 22,000 people who started either a GLP-1 receptor agonist or a sulfonylurea, an older class of diabetes medicine. The results were presented at the European Respiratory Society Congress by Dr Bohee Lee. Across the class, people with airway disease who were prescribed GLP-1 therapies appeared to have fewer attacks than similar people on other diabetes medicines, and the effect was strongest with semaglutide in people with asthma.
Everyone in the analysis already qualified for these drugs because of type 2 diabetes or obesity. Nobody was prescribed semaglutide for a lung condition, and the researchers were explicit that nobody should be.
Inside the Comparison the Researchers Ran
Record linkage studies work by finding people who look alike on measurable characteristics and then comparing what happened to them. The strength here is scale and real-world relevance. Each of the four studies was far larger than any asthma trial of these drugs, and the patients were ordinary primary care patients rather than a screened trial population.
The weakness is that the two groups chose, or were prescribed, different drugs for reasons the records may not fully capture. Someone who started on semaglutide in recent years may differ from someone who started on a sulfonylurea in ways that also affect asthma control, including body weight, how closely they are followed and how consistently they take medication. Statistical adjustment reduces that problem without eliminating it.
Bloom described the results as encouraging while drawing a firm line around them. She said they "should not change treatment decisions on their own" and that people with asthma or COPD should not start these drugs for a lung condition outside current prescribing guidance. She added that the association still needs confirmation in clinical trials.
The Missing Piece in the Drug Trials
Bloom also pointed to a gap in how these medicines were tested in the first place. Asthma and COPD outcomes were not included in the major GLP-1 drug trials. That means the drugs have been prescribed to millions of people with airway disease without anyone systematically measuring what happened to their lungs.
Dr Alexander Mathioudakis, chair of the European Respiratory Society's group on airway pharmacology and treatment and senior lecturer in respiratory medicine at the University of Manchester, was not involved in the study. He called the work one of the largest real-world studies in this area and one of the first to examine whether effects differ between individual GLP-1 drugs rather than treating the class as one thing.
His practical point was about how respiratory care is organized. Obesity and metabolic problems are common in people with asthma and COPD and are often under-recognized as problems that can be addressed. "It highlights the need to consider metabolic health as part of respiratory care," he said.
The Population This Could Reach in the United States
Asthma affects a large share of American adults and children. Federal health statistics on asthma show 8.6 percent of adults and 6.5 percent of children currently had asthma in 2024, with 3,722 asthma deaths recorded that year. The same source counts about 1.4 million emergency department visits with asthma as the primary diagnosis, drawn from 2022 survey data. GLP-1 prescribing has expanded rapidly over the same period, which means a substantial group of Americans already sits in both categories.
For those patients, the finding is genuinely relevant, and it is also easy to overread. If a person with asthma and type 2 diabetes is already taking semaglutide, this analysis suggests a possible additional benefit at no additional cost or risk. It does not suggest that asthma should factor into whether a clinician prescribes the drug, and it does not suggest that anyone should reduce inhaler use. Basic asthma control guidance has not changed.
Access remains the harder problem. Coverage for GLP-1 medicines varies sharply by plan and by indication, and many patients with obesity but not diabetes still face denials or high out-of-pocket costs. Nothing in this study changes coverage rules. Patients facing a denial can ask a prescriber about prior authorization, appeals, and manufacturer assistance programs, though those routes are slow and inconsistent.
The Standard of Proof That Has Not Been Met
The results were presented as a conference abstract and have not been published in a peer-reviewed journal. Conference abstracts are preliminary by design, with limited space for methods, and the figures can shift before full publication.
Observational analyses of this kind have a specific track record worth remembering. Record linkage studies have repeatedly suggested benefits for widely used drugs that later randomized trials did not confirm, because the people who receive a treatment differ systematically from those who do not. Hormone therapy and heart disease are a classic example. That history does not mean this result is wrong. It means the correct response is a trial, not a prescription change.
What would settle it is a randomized trial in people with asthma or COPD that measures attacks, exacerbations, lung function, symptoms, and quality of life directly. Mathioudakis said trials including those respiratory outcomes are exactly what the field needs, and no such trial has reported results.
The abstract was one of several airway disease presentations released through the society's congress news channel during the meeting. Until a trial reports, the reasonable position for patients is clear. Nobody with asthma or COPD should ask for semaglutide as a lung treatment, and nobody already taking it should change anything based on this presentation. Anyone with both an airway disease and diabetes or obesity can reasonably raise the finding at a routine appointment, where the conversation is likely to be about metabolic health generally rather than about this specific result.
People with asthma should also continue their prescribed controller inhalers regardless. Attacks are prevented by consistent controller use, and standard treatment guidance has not moved. Stopping or reducing that treatment based on an unpublished abstract would be a clear step backward.
Key Questions Answered
What did the study find? People with asthma who started semaglutide had close to 40 percent fewer asthma attacks than similar patients started on sulfonylureas, and 20 percent fewer COPD flare-ups.
How large was the analysis? Four parallel studies, each covering between 20,000 and 22,000 people, drawn from United Kingdom electronic medical records.
Was this a clinical trial? No. It was an observational analysis of routine medical records, which can show associations but cannot establish that the drug caused the reduction.
Should people with asthma ask for semaglutide? No. The lead researcher said explicitly that people with asthma or COPD should not start these drugs for a lung condition outside current prescribing guidance.
Who was included in the analysis? Only people who already qualified for GLP-1 medicines because of type 2 diabetes or obesity, and who also had asthma or COPD.
Has the research been peer reviewed? No. It was presented as an abstract at the ERS Congress in Barcelona and has not yet been published in a peer-reviewed journal.
What would confirm the finding? A randomized clinical trial in people with asthma or COPD that measures respiratory outcomes directly. No such trial has reported results.
