Metformin use was associated with approximately a 30% reduction in asthma attacks, with an additional 40% reduction when combined with glucagon-like peptide-1 receptor agonists, according to a study published in JAMA Internal Medicine.
The study investigated the association between antidiabetic medications and asthma exacerbations using data from the UK Clinical Practice Research Datalink (CPRD) from 2004 to 2020. The research employed two distinct analytical approaches: a self-controlled case series (SCCS) with 4,278 patients (61.2% women; mean age 52.9 years) and a propensity-weighted cohort of 8,424 patients.
The analysis showed consistent results across both approaches, with metformin associated with fewer asthma attacks in both the SCCS (incidence rate ratio [IRR], 0.68; 95% CI, 0.62-0.75) and cohort analyses (hazard ratio [HR], 0.76; 95% CI, 0.67-0.85). The reduction occurred within 3 months and remained for the subsequent 9 months, with 14 patients needing to be treated with metformin for 12 months to prevent one asthma attack. The addition of GLP-1RAs was associated with a further reduction in asthma attacks (IRR, 0.60; 95% CI, 0.49-0.73).
In the broader asthma cohort of more than 2 million patients, more than half had overweight or obesity. Among those with overweight or obesity but without a type 2 diabetes diagnosis, 71.2% had no glycemic assessment, and among those with elevated hemoglobin A1c levels, only 4.1% received a diabetes diagnosis within 2 years.
The SCCS approach controlled for time-invariant confounders by using each patient as their own control, while the cohort analysis, weighted by propensity scores, supported these findings. Both approaches demonstrated that the associations were independent of glycemic control and weight loss. Negative control analyses found no evidence of significant bias.
The findings are consistent with previous evidence suggesting potential anti-inflammatory and airway remodeling effects of metformin and GLP-1RAs. Further research, including randomized clinical trials and mechanistic studies, is needed to confirm these effects and determine the mechanism of action in asthma.
Full disclosures can be found in the published study.
