Metformin lowers asthma exacerbations independent of blood sugar control: Study

Worse asthma morbidity is closely related to diabetes. Metformin, commonly given in diabetic patients, may have a role in patients with asthma and glycaemic dysfunction or poor blood sugar control.

A group of researchers from Johns Hopkins University School of Medicine, Baltimore Maryland, U.S.A conducted a study to demonstrate an association between metformin use and asthma exacerbations among patients with diabetes.

They selected a total of 1,749 adults with asthma and diabetes who were reported in the Johns Hopkins EHR from April 1, 2013 to May 31, 2018. All the adults with asthma and diabetes were followed from the first hemoglobin A1c (HbA1c) test to an asthma-related systemic corticosteroid prescription, emergency department (ED) visit, or hospitalization. Multivariable Cox models estimated time to each outcome associated with metformin use, modeled as either time-invariant (status at HbA1c testing) or time-dependent (based on fill data). Mediation of results by HbA1c was assessed. Also, sensitivity analysis was performed by propensity score matching.

The findings of the study are as follows:

· Metformin use at entry was associated with a lower hazard of asthma-related ED visits but not with steroid prescription or hospitalization.

· HbA1c did not mediate the association with ED visits.

· With metformin exposure modeled as time-dependent, metformin use was additionally associated with lower hazard of asthma-related hospitalization

· All the results were consistent within a sub-cohort of 698 metformin users matched 1:1 to non-users by propensity score.

The researchers concluded that Metformin use, independent of glycemic control and obesity was associated with a lower hazard of asthma-related ED visits and hospitalizations. Thus, proposing that Metformin may have benefit in patients with asthma and glycemic dysfunction.

Reference:

Metformin use and risk of asthma exacerbation among asthma patients with glycemic dysfunction by Wu T et. al published in The Journal of Allergy and Clinical Immunology: In Practice.

https://doi.org/10.1016/j.jaip.2021.07.007