News · Heart & Metabolic
GLP-1 drugs went with 12% fewer asthma attacks than a rival diabetes drug, in 100,746 patients
People with asthma and type 2 diabetes take drugs chosen for blood sugar. Health records from many countries suggest the choice may also track with how often asthma flares, at least over six months.
- An observational study of 100,746 adults with both asthma and type 2 diabetes, drawn from multinational health records.
- Those starting a GLP-1 drug were compared with those starting an SGLT-2 inhibitor, matched on their characteristics.
- Over six months, GLP-1 users had 12% lower risk of an asthma attack.
- They were also 21% less likely to need a course of steroid tablets.
- By one year the difference had faded, and prescribing is not random, so this is not proof.
Asthma and type 2 diabetes overlap more than people expect, partly because excess weight makes both more likely. That overlap raises a practical question: if someone has both, does it matter which diabetes drug they are given?
A study in Pharmacotherapy compared two modern diabetes drug classes in 100,746 patients who had both conditions. Over six months, those on GLP-1 drugs had fewer asthma attacks than those on SGLT-2 inhibitors.
What an asthma attack involves
MedlinePlus describes asthma as a chronic (long-term) lung disease in which your airways can become inflamed and narrowed, causing wheezing, coughing and tightness in the chest. When those symptoms get worse than usual, it notes, it is called an asthma attack or flare-up.
Attacks are what asthma care tries to prevent, because each one carries risk and often requires steroid tablets. The authors point out that antihyperglycemic drugs have shown benefits in asthma control, but that evidence comparing the main modern classes has been inconsistent.
How the diabetes drug comparison worked
The researchers used TriNetX, a network that pools de-identified electronic health records from many countries, and found adults with both asthma and type 2 diabetes who started one of the two drug classes between 2013 and 2024.
To make the groups comparable, they matched people one to one on their recorded characteristics, leaving 28,831 in each group. A total of 100,746 patients were included before matching. The main outcome was the time to a first asthma attack, with symptom episodes and steroid courses as secondary measures.
What happened to asthma attacks
Over six months, the GLP-1 group did better. GLP-1 RAs were associated with a decreased risk of asthma exacerbation compared with SGLT-2is, about 12% lower, along with 11% lower risk of an asthma symptom episode and 21% lower risk of needing systemic steroids.
The picture changed with time. When follow-up was extended to one year, the association for asthma exacerbation was not observed, with the two groups essentially level. The authors report both, which is the honest way to present it.
Why the diabetes drug choice matters in asthma
Doctors already choose between these classes on grounds of heart failure, kidney function, weight and cost. If one also tracked with fewer asthma attacks, that would be a tiebreaker worth knowing, particularly for patients whose asthma is hard to control.
The size of the difference is modest and the timing is odd, which argues for caution rather than a change in practice. The authors say as much: as these findings reflect associations rather than causal effects, further investigation through randomized trials is warranted.
What an asthma records comparison cannot prove
Prescriptions are not random. People given GLP-1 drugs may differ from those given SGLT-2 inhibitors in weight, severity, insurance and how often they see a doctor, and matching balances only what the records contain.
Asthma attacks in databases are identified from codes and prescriptions, which can miss milder flares or count treatment for something else. Weight change, inhaler use and asthma severity were not the focus. And the disappearance of the effect at one year raises the possibility that the early difference reflects who started, and stayed on, each drug.
What this changes for patients with asthma and diabetes
Nothing yet in terms of prescribing. The reasons for choosing a diabetes drug remain blood sugar control, heart and kidney protection, side effects and cost.
If your asthma is poorly controlled and you also have type 2 diabetes, it is a reasonable thing to raise at a review, alongside the measures that clearly do reduce attacks: taking a preventer inhaler regularly, checking inhaler technique, and treating hay fever, reflux and excess weight where they contribute.
People also ask
What did the study find?
Compared with SGLT-2 inhibitors, GLP-1 receptor agonists were associated with a lower risk of asthma exacerbation (hazard ratio 0.88, 95% CI 0.85 to 0.91), of asthma symptoms (0.89, 0.82 to 0.97) and of systemic corticosteroid use (0.79, 0.76 to 0.82) over six months. Extending follow-up to a year, the exacerbation difference was no longer seen (0.95, 0.89 to 1.02).
What is an asthma exacerbation?
An asthma attack: a flare of wheezing, coughing and breathlessness that usually needs extra treatment, often a course of steroid tablets, and sometimes urgent care.
What are these two drug classes?
GLP-1 receptor agonists, such as semaglutide and liraglutide, and SGLT-2 inhibitors, such as empagliflozin and dapagliflozin. Both lower blood sugar in type 2 diabetes and both have heart and kidney benefits.
Why might a diabetes drug affect asthma?
Proposed reasons include weight loss, since excess weight worsens asthma, and effects on inflammation in the airways. This study did not test mechanisms.
Why did the effect disappear at one year?
It may mean the early difference reflected something temporary, or that people switched or stopped drugs over time. The authors report both results rather than choosing one.
Should asthma change my diabetes prescription?
Not on this evidence. Diabetes drugs are chosen for blood sugar, heart and kidney reasons, and asthma treatment has its own guidelines. Raise it with your doctor rather than switching. This is general information rather than medical advice.