Metformin use, independent of glycemic con- trol and obesity, was associated with lower hazard of asthma-related emergency department (ED) visits and hospitalizations, and thus, may benefit patients with asthma and glycemic dysfunction, according to a study published in The Journal of Allergy and Clinical Immunology: In Practice. Investigators queried Johns Hopkins electronic health records from April 1, 2013, to May 31, 2018 among adults with asthma and diabetes who were followed from first A1C test to an asthma-related systemic corticosteroid prescrip- tion, ED visit, or hospitalization. Multivariable Cox models estimated time to each outcome associated with metformin use, modeled as either time-invariant (status at A1C testing) or time- dependent (based on fill data). Mediation of re- sults by AIC was assessed and sensitivity analyses were performed by propensity score matching. In a cohort of 1,749 adults with asthma and diabetes, metformin use at entry was associated with a lower hazard of asthma-related ED visits (aHR, 0.40; 95% CI, 0.22-0.75) but not steroid prescription (aHR 0.89; 95% CI, 0.70-1.13) or hospitalization (aHR, 0.38; 95% CI, 0.13-1.12). A1C 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 (aHR, 0.30; 95% CI, 0.09-0.93). Results were consistent within a sub-cohort of 698 metformin users matched 1:1 to non-users by propensity score.
