Late Breaking Abstract - Exacerbation of asthma in childhood: seasonal pattern and risk factors

Abstract

Background: Secondary analysis of asthma cohort studies data can identify risk factors for asthma exacerbation. Objective: To assess risk factors for future asthma exacerbation, from amongst demographic data, atopic and previous exacerbation history, treatment adherence, asthma control and severity. Methods: 90 children, aged 5.9 - 16.2 years, with moderate to severe asthma, took part in a trial, comparing guideline-based asthma management to guideline-based management modified according to Fractional Exhaled Nitric Oxide (FeNO). Participants were extensively characterized at baseline and were followed up every 2 months for a year. Exacerbations were defined as a worsening of symptoms requiring oral steroids or hospital admission. Results: Exacerbations (82) demonstrated a seasonal pattern with peaks in spring and autumn (29%). 49% of children experienced at least one asthma exacerbation. Exacerbation risk was associated with exacerbation history during the previous year; 59% increase in risk associated with passive smoking, 15% increase per course of oral steroid, 5% increase per day of hospital admission and 9% increase per one point increase in Composite Asthma Severity Index (CASI) score at baseline was noted. Risk of exacerbation was positively associated with inhaled steroid requirement and negatively with FEV1 at baseline. Specific predictors of autumn exacerbation were hospital admissions, oral steroid use in the previous year and baseline CASI score. Conclusions: Asthma exacerbation frequency seems to be affected by seasonal factors. In the future, public strategies/interventions could target modifiable risk factors, such as asthma control, in order to reduce exacerbations.