Asthma in Remission: Can Relapse in Early Adulthood Be Predicted at 18 Years of Age?

Abstract

Purpose of the Study. To determine the frequency of asthma relapse in young adults in remission at 18 years over an 8-year follow-up period and to determine possible prognostic indicators of relapse. Study Population. A subset of 68 subjects in asthma remission at 18 years of age from of a cohort of 1037 subjects born in New Zealand from 1972 to 1973 followed from birth through the Dunedin Multidisciplinary Health and Development Study. Methods. The cohort was enrolled at 3 years old and followed every 2 years until age 15 and again at ages 18, 21, and 26. Subjects were given respiratory questionnaires and lung-function assessment by spirometry. Methacholine testing for bronchial hyperreactivity was performed at 9, 11, 13, 15, and 21 years of age in some. Atopy was assessed by skin tests at ages 13 and 21 years. Remission of asthma at 18 years was defined as no current symptoms with previous reported symptoms at ≥2 previous assessments. Results. At 18 years of age, there were 108 subjects with current asthma and 68 subjects with previous asthma in remission. Those in remission at age 18 had a later age of onset of asthma (6.4 ± 4.5 vs 4.7 ± 4 years for current asthma) and had better lung function. Those with current asthma at age 18 were more atopic at age 18, with higher skin-test reactivity for house dust mite and cat. They had higher bronchial hyperreactivity by methacholine at all age points between 9 and 18 than their counterparts in remission. Of the 68 subjects in remission at age 18, 44 remained in remission and 24 relapsed by age 26. Multiple logistic-regression analysis identified dust mite sensitization at age 13 (odds ratio [OR]: 2.63; 95% confidence interval [CI]: 1.23–5.61) and decreased forced expiratory volume in 1 second/forced vital capacity ratio at age 18 (OR: 0.9 per 1% higher ratio; 95% CI: 0.81–0.99). Those with better lung function had lower likelihood of asthma relapse by 16 years of age. Variables such as methacholine reactivity and tobacco smoking were not significant predictors. Conclusions. Approximately one third of young adults with a history of asthma in childhood in remission at 18 years of age will relapse by 26 years of age. Most will have mild disease at relapse. There were weak associations with atopy and lower lung function at a young age as predictors of asthma relapse. Reviewer Comments. Families often ask if their child will “outgrow” asthma. This study was consistent with other studies in finding that approximately one third of those in remission may have relapse, but the factors found by other groups as potential predictors such as atopy, lower lung function, and tobacco smoking were not as strong.