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Metformin may lower risk for exacerbations in patients with asthma, diabetes

Metformin treatment may lower the risk for asthma exacerbations in patients with diabetes, a recent retrospective cohort study suggested.

“There is emerging evidence that treatment of metabolic dysfunction, especially diabetes, may make asthma better,” Tianshi David Wu, MD, MHS, fellow in pulmonary and critical care medicine at Johns Hopkins School of Medicine, told Healio Pulmonology. “More research is needed before these results can be directly applied clinically. But if metformin proves to be effective in reducing asthma morbidity, this opens an additional pathway of therapy to patients whose asthma is partially driven by metabolic dysfunction.”

Researchers examined prescription claims from 23,920 adults aged 18 years and older with both asthma and diabetes via the IBM MarketScan Database from Jan. 1, 2010, to Dec. 31, 2016. Patients were included if they had been enrolled for 1 year or more in a health plan that submitted prescription claims over the course of enrollment, and if they had at two or more outpatient or one inpatient code. Patients diagnosed with interstitial lung disease, COPD or bronchiectasis and patients with a contraindication for metformin use, a rheumatologic condition possibly requiring systemic corticosteroids for symptoms unrelated to asthma and individuals with type 1 diabetes were excluded.

The primary outcome was a composite of hospitalization where asthma was the principal diagnosis, an ED encounter where asthma was diagnosed or filling of any systemic corticosteroid within 14 days of an asthma-related ambulatory visit. Asthma severity was measured by the classes of asthma medications used, amount of outpatient visits and number of exacerbations. The number of all-cause hospitalizations and the Charlson Comorbidity Index were used to quantify comorbid illnesses and Cox proportional hazard models were used to estimate associations between metformin use and risk for the primary outcome and its individual components.

Metformin use was associated with a decreased risk for asthma exacerbation (HR = 0.92; 95% CI, 0.86-0.98). Additionally, lower risks for asthma-related hospitalizations (HR = 0.67; 95% CI, 0.5-0.91) and ED visits (HR = 0.81; 95% CI, 0.74-0.88) were observed in patients treated with metformin. However, there were no differences in corticosteroid use between metformin users and nonusers (HR = 0.96; 95% CI, 0.86-1.03).

The average patient age of the study group, two-thirds of which were women, was 52 years, with 11% of the population experiencing at least one asthma exacerbation in the previous year.

“We are far away from being certain that metformin may have a beneficial role in asthma, and I would consider this study to be an initial step,” Wu said. “More research, especially in clinical studies involving human volunteers, is needed to confirm these results.” – by Eamon Dreisbach

Disclosures: Wu reports no relevant financial disclosures.