Severity of obstructive airways disease by age 2 years predicts asthma at 10 years of age

Background: Predicting school-age asthma from obstructive airways disease (OAD) in early life is difficult, even when parental and children's atopic manifestations are taken into consideration. Objective: To assess if the severity of OAD in the first 2 years of life predicts asthma at 10 years of age. Methods: From a nested case control study within the Environment and Childhood Asthma study, 233 2-year-old subjects with recurrent (>= 2 episodes) bronchial obstruction (rBO+) and 216 subjects without bronchial obstruction (rBO-) underwent clinical examination, parental interview, treadmill test and metacholine bronchial hyperresponsiveness (BHR) measurement at 10 years. A severity score at 2 years was calculated by frequency, persistence of bronchial obstruction and hospital admissions because of OAD. Main outcomes: Current asthma at 10 years (asthma with symptoms and/or asthma medication during the past year and/or positive treadmill test). Secondary outcome was metacholine BHR at 10 years. Results: Compared with rBO- subjects, adjusted odds ratio (95% CI) of current asthma among rBO+ was 7.9 (4.1, 15.3), and among rBO+ with a severity score of >5, 20.2 (9.9, 41.3). In receiver operated characteristic analysis, positive and negative predictive values demonstrated the applicability and value of the score, with an optimal cut-off at severity score 5. Children with severity score.5 had severe BHR more often (PD20 metacholine <1 mu mol) than children with a lower or 0 score (p= 0.0041). Conclusion: Using a simple scoring system, a high severity score of OAD by 2 years of age is a strong risk factor for, and may predict, current asthma at 10 years of age.