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 (> or = 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 micromol) 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.