Page 25 - ADULT-ONSET ASTHMA PREDICTORS OF CLINICAL COURSE AND SEVERITY

PROGNOSIS IN CHILDHOOD – AND ADULT – ONSET ASTHMA
One important dis nc ve variable for asthma phenotyping is age of asthma onset, making a division in childhood- and adult-onset asthma1-6. Studies have shown clear di erences between childhood-onset asthma and adult-onset asthma 7, 8. For example, onset of asthma in adulthood is associated with upper airway symptoms 9, 10 and in contrast to childhood asthma, the impaired lung func on is independent of disease dura on 8.
However, most follow-up studies describe only the clinical course of childhood-onset asthma. These studies have shown that atopic children with a history of wheezing before the age of 3 years are at risk for an impaired lung func on at school age11. Moreover, children with early lung func on impairment combined with environmental exposure are at risk for developing persistent asthma12. Childhood asthma might only exist during childhood and adolescence but more than 40% will have asthma as adults13, 14. Factors such as atopy, parental asthma, recurrent respiratory infec ons and the asthma severity in childhood have been shown to predict asthma persistence and severity into adulthood 15. Childhood-asthma severity is also associated with faster lung func on decline in adulthood 15, just as persistent airway hyperresponsiveness and frequent asthma exacerba ons 16-18.
On the contrary, the clinical course of adult-onset asthma has been studied to a much lesser extent. The limited available literature indicates that the prognosis tends to be poor with low remission rate and a fast deteriora on of lung func on 19. From cross-sec onal studies it is known that adult-onset asthma pa ents are o en non-atopic 9, 20 and have severe air ow obstruc on 21, 22. Adult-onset asthma itself is also a heterogeneous disease that consists of di erent phenotypes such as eosinophilic in amma on-predominant asthma, obese women 5, 23 and occupa onal asthma24, 25. The la er is a speci c phenotype provoked by workplace substances that accounts for approximately 15% of all adult-onset asthma pa ents 26, 27.
As asthma phenotypes di er with regard to asthma triggers, clinical characteris cs and in amma on, also the prognosis might be variable. Many unresolved issues exist about the clinical course and factors determining the prognosis. In order to o er pa ents be er- tailored treatment, it is relevant to acknowledge these prognos c factors. Therefore, the aim of this review is to summarize the known determinants of adult-onset asthma prognosis, supplemented with data on adult asthma in general. Results are presented according to factors associated with lung func on decline, increased asthma severity and asthma remission.
THE PROGNOSIS OF ADULT-ONSET ASTHMA
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