A retrospective cohort study conducted in Hong Kong among adults with co-existing asthma and diabetes mellitus (DM) has found a lower risk of asthma exacerbation with glucagon-like peptide-1 receptor agonist (GLP-1 RA) vs dipeptidyl peptidase-4 inhibitor (DPP-4i) treatment.
Comorbid asthma and DM are common, and research suggests that coexistence of the two worsens asthma control. [Can Respir J 2021;doi:10.1155/2021/8830439] Use of GLP-1 RAs or DPP-4is has been reported to improve asthma symptoms or prevent exacerbations in some studies, yet evidence has been mixed and no dedicated study has compared the impact of GLP-1 RA vs DPP-4i use on asthma exacerbation rates in patients with comorbid DM. [Ann Am Thorac Soc 2024;21:1496-1506; Am J Respir Crit Care Med 2021;203:831-840; Pragmat Obs Res 2017;8:231-240; J Allergy Clin Immunol Pract 2024;12:2035-2044]
The present study included 3,295 patients (mean age, 68 years; female, 63.9 percent) with both asthma and DM managed under the Hong Kong Hospital Authority, who were prescribed a GLP-1 RA (n=102) or a DPP-4i (n=3,193) in 2018 for ≥6 months. They were followed from January 2018 (or the start date of GLP-1 RA or DPP-4i, whichever was later) to December 2023 (or the date of discontinuation of GLP-1 RA or DPP-4i or death, whichever was earlier). [J Asthma Allergy 2026;19:622748]
The researchers from the University of Hong Kong noted the substantial difference in the number of patients on GLP-1 RA vs DPP-4i and performed propensity score matching with optimal full matching. “By doing this, we matched the baseline characteristics of the patients prescribed GLP-1 RA or DPP-4i, thus avoiding the issues of possible confounders, without changing the nominal numbers of subjects in each group,” they explained.
During the study period, the primary outcome of conditional mean number (± standard deviation [SD]) of asthma exacerbations requiring hospitalization was 0.50 ± 3.02 in the GLP-1 RA group and 0.83 ± 5.20 in the DPP-4i group. GLP-1 RA treatment was associated with a 48.7 percent lower expected number of events vs DPP-4i in the treated population (p<0.001).
“The benefit [observed] may be driven by the effects of GLP-1 on pulmonary function and disease,” suggested the researchers. “In murine models of lung injury, the administration of exogenous GLP-1 RAs has been shown to confer significant protection against pulmonary inflammation and airway hyperresponsiveness.” [Endocrinology 2020;doi:10.1210/endocr/bqaa201]
The conditional mean number (± SD) of ad hoc outpatient visits resulting ioral corticosteroid prescriptions was 0.56 ± 1.68 vs 0.81 ± 2.90 in the GLP-1 RA vs DPP-4i group, translating to a 65.7 percent lower expected number of events in the treated population (p=0.005).
Similarly, the conditional mean numbers of any asthma exacerbation episodes and of emergency department visits without hospitalization were lower in the GLP-1 RA vs DPP-4i group. GLP-1 RA vs DPP-4i treatment was associated with a 58.1 percent lower expected number of any asthma exacerbation episodes (p<0.001) and a 62.2 percent lower expected number of emergency department visits without hospitalization (p=0.009).
“Our study suggested the potential clinical benefits of GLP-1 RA among patients with co-existing asthma and DM. In the current cohort, patients treated with GLP-1 RA had significantly fewer asthma exacerbations of all severities, ranging from those managed in the outpatient setting to those requiring hospitalization,” concluded the researchers.