A new study published in JAMA Internal Medicine reveals that metformin, a first-line medication for type 2 diabetes, is associated with a significant reduction in asthma attacks among patients with both conditions. The research further indicates that adding glucagon-like peptide-1 receptor agonists (GLP-1RA) to metformin therapy provides an additional protective effect against asthma exacerbations. This finding could represent a significant advancement in managing asthma in diabetic patients.
The study, utilizing data from the UK Clinical Practice Research Datalink (CPRD) Aurum, included 12,702 patients with asthma. Researchers employed both a self-controlled case series (SCCS) and a metformin new user cohort with inverse probability of treatment weighting (IPTW) to enhance the robustness of their findings. The primary outcome was the first asthma exacerbation requiring a short course of oral corticosteroids, unscheduled asthma-related hospital attendance, or resulting in death within a 12-month follow-up period.
The results demonstrated that metformin was associated with approximately a 30% reduction in asthma attacks (SCCS: IRR, 0.68; 95% CI, 0.62-0.75; IPTW: HR, 0.76; 95% CI, 0.67-0.85). Furthermore, the addition of GLP-1RA was associated with an additional 40% reduction (SCCS: IRR, 0.60; 95% CI, 0.49-0.73), suggesting a synergistic effect. These associations were observed regardless of glycemic control, weight, or asthma phenotype.
Implications for Asthma and Diabetes Management
"These results suggest that metformin was associated with a significant lowering of asthma attacks and the addition of glucagon-like peptide-1 receptor agonists was associated with a synergistic additive effect," the authors noted. This is particularly relevant given that elevated body mass index (BMI) and type 2 diabetes are prevalent in asthma patients and are known to increase the risk of asthma attacks.
The study's findings suggest that the benefits of metformin and GLP-1RA on asthma attacks are likely mediated through mechanisms other than glycemic control or weight loss. This is supported by experimental studies showing that both metformin and GLP-1RA can mitigate airway inflammation, hyperresponsiveness, and remodeling.
Study Design and Limitations
The study used a triangulation approach, combining a self-controlled case series (SCCS) and a metformin new user cohort with inverse probability of treatment weighting (IPTW) to analyze data from the UK Clinical Practice Research Datalink (CPRD) Aurum linked hospital admissions and mortality data from 2004 to 2020. This design strengthens the validity of the findings. However, the study is observational, and therefore, causality cannot be definitively established. Further research is needed to confirm these findings and elucidate the underlying mechanisms.
Current Treatment Landscape
Currently, asthma management primarily focuses on inhaled corticosteroids and bronchodilators. For patients with both asthma and diabetes, managing both conditions can be challenging. This study offers a potential new avenue for therapeutic intervention by leveraging medications already used for diabetes management to also improve asthma control.
