Predictors of asthma relapse in patients who attended an emergency department.

Background: Patients with asthma exacerbations and frequent relapses that require admission to the emergency department (ED) often have more severe disease, worse quality of life, and higher use of health care resources.
Objective: The aim of this study was to identify potential predictors of relapse after patients are treated in an ED for an asthma exacerbation.
Methods: A retrospective, noninterventional cohort study was conducted in adult patients who attended the ED of a tertiary hospital in 2014 for an asthma exacerbation. We analyzed the subpopulation who experienced at least one relapse (returned to the ED < 15 days after the previous event).
Results: Fifty-two of 831 patients experienced 66 relapses after going to the ED (mean ± standard deviation [SD] age, 58.5 ± 23.4 years). The average ± SD probability of a relapse was 6 ± 0.8%. The frequency of episodes was higher in May and November. Twenty-four patients had ≥260 blood eosinophils/μL, including 17 who had ≥400 eosinophils/μL. Only 15% of the patients were referred to an asthma specialist at discharge. Factors related to a higher probability of relapse were the following: having multiple visits to the ED in 1 year, uncontrolled asthma, wheezing in the pulmonary auscultation, peripheral eosinophilia with ≥400 eosinophils/ μL, and being discharged in the first visit to the ED (p < 0.01 for all).
Conclusion: In this population, patients who had multiple ED visits in 1 year, those with uncontrolled asthma, wheezing, ≥400 blood eosinophils/μL, or who had been discharged at the first ED visit are at higher risk of relapse.