Adult Asthma Severity in Individuals With a History of Childhood Asthma

Abstract

Purpose of the Study. Childhood asthma has a range of outcomes in adulthood. This study sought to identify clinical features and exposures associated with persistence and severity of childhood asthma in adulthood. Study Population. Subjects had been previously enrolled in the Childhood Asthma Study, a double-blind, randomized, placebo-controlled trial designed to study the role of immunotherapy as an adjunct treatment. The 121 original study members, aged 5 to 12 years at the time of randomization, had moderate-to-severe asthma and had been followed for at least 1 year before enrollment. Evaluations performed during the original study included daily medication-symptom diaries, home allergen analysis, allergy skin testing, and methacholine challenges. The cohort had varied socioeconomic status, genders, and ethnicities. For this study an attempt was made to enroll all original participants. Methods. Eighty-five of the original subjects participated in the adult evaluation, underwent spirometry and inhalant allergy skin testing, and completed questionnaires regarding their interim medical history, asthma symptoms, and medications. Asthma severity was classified by using a modified version of the 1997 National Asthma Education and Prevention Program algorithm. Postbronchodilator spirometry was used for severity categorization. Subjects were categorized in the most severe category for which they qualified. Results. Thirteen (15.3%) of these young adults, aged 17 to 30 years, were in remission. Another 19 (22%) had only mild intermittent asthma. There were 12 (14%) with mild persistent asthma, 25 (29%) with moderate persistent asthma, and 16 (19%) with severe persistent disease. Subjects in remission, compared with subjects with mild intermittent or persistent asthma, had lower serum immunoglobulin E in childhood (412 vs 1136 vs 968 ng/mL, respectively) and fewer positive allergy skin tests (7 vs 9 vs 10, respectively, from a panel of 18 allergens). Subjects in remission also had milder childhood asthma, indicated by lower average daily medication usage scores and lower percentage of days on inhaled corticosteroids (13.7% vs 24.7% vs 40.9%). There was no association found between current asthma severity and childhood immunotherapy. Conclusions. The prognosis of childhood allergic asthma in adulthood is largely determined early in life. The degree of atopy seems to be a critical determinant of asthma persistence. Reviewer Comments. The authors point out that numerous studies of the natural history of asthma have suggested associations between childhood atopy and disease severity with risk of asthma persistence and severity in later childhood and adulthood. It remains to be seen whether there is any sort of intervention at a very early phase in the disease that will more favorably alter the course of asthma. Thus far, there are no compelling candidates.