Tirzepatide and semaglutide show no difference in asthma exacerbation risk, study finds

Adults who have both asthma and type 2 diabetes faced nearly the same risk of an asthma exacerbation over 12 months whether they started tirzepatide or semaglutide, according to a retrospective study of US health records published September 7, 2026 ^[1].

The analysis, in the Journal of Asthma and Allergy, matched 8,176 pairs of adults who began one of the two drugs between June 1, 2022, and December 1, 2024 ^[1]. Exacerbation risk over the following year was 11.0 percent for tirzepatide users and 11.1 percent for semaglutide users, with a hazard ratio of 1.00 and a 95 percent confidence interval of 0.91 to 1.10 ^[1]. The authors report the result held across sensitivity and subgroup analyses ^[1].

The one difference that emerged involved rescue inhalers. Tirzepatide was associated with a slightly lower risk of short-acting beta-agonist (SABA) prescriptions, with a hazard ratio of 0.92 (95% CI 0.88–0.96), while the risk of systemic corticosteroid use was similar between the two groups, at a hazard ratio of 1.01 (95% CI 0.96–1.05) ^[1].

Tirzepatide is sold as Mounjaro and Zepbound; semaglutide as Ozempic, Wegovy and Rybelsus. The researchers had expected tirzepatide to come out ahead. It is the first drug to combine GIP and GLP-1 activity, and it has produced greater weight loss and blood sugar improvement than GLP-1-only drugs in other studies ^[1]. Earlier laboratory work suggested incretin-based medicines might reduce airway inflammation and bronchial hyperresponsiveness ^[1]. The study's stated hypothesis was that tirzepatide would be linked to a lower risk of asthma exacerbation than semaglutide. That is not what the data showed ^[1].

The study used the TriNetX US Collaborative Network, which covers more than 65 healthcare organizations ^[1]. Everyone included was 18 or older with at least two medical encounters for asthma and two for type 2 diabetes in the year before starting treatment, and no prior GLP-1 or GIP/GLP-1 use during that year ^[1]. Patients with type 1 diabetes were excluded ^[1]. Follow-up ran 12 months, and the study period ended December 1, 2025 ^[1].

An earlier TriNetX study compared the two drugs in a broader group of patients with asthma and reported differences in asthma-related outcomes, including obstructive sleep apnea; patients with type 2 diabetes were only a subgroup of that population ^[1].

Why it matters for patients

About 13 to 16 percent of people with asthma also have type 2 diabetes, and having both conditions is tied to poorer asthma control, more frequent and more severe exacerbations, and greater use of healthcare than asthma alone ^[1]. Because tirzepatide and semaglutide are prescribed mainly for metabolic conditions, this study restricted its comparison to people who had both diagnoses ^[1].

For anyone with asthma and type 2 diabetes weighing the two drugs, the analysis offers no evidence that the dual-acting option does more for breathing than the GLP-1-only option. The matched 11.0 percent and 11.1 percent figures are close enough that the difference could reflect chance.

The study was observational, based on electronic health records rather than random assignment. Matching was used to balance baseline characteristics ^[1], but that approach cannot account for factors that were never recorded, and it cannot prove cause and effect. The design also had no group receiving neither drug, so it does not show whether either medicine lowers exacerbation risk compared with other diabetes treatment.

What happens next

The authors conclude that randomized controlled trials are needed to clarify what role, if any, GLP-1-based therapies play in patients with asthma and type 2 diabetes ^[1]. Whether such a trial is planned or underway has not been reported. How the authors defined an asthma exacerbation in the health records, and how they handled people who stopped or switched drugs during the 12 months, are not detailed in the study summary reviewed here.