Page 164 - ADULT-ONSET ASTHMA PREDICTORS OF CLINICAL COURSE AND SEVERITY

ADULT-ONSET ASTHMA – PREDICTORS OF CLINICAL COURSE AND SEVERITY
SUMMARY AND CONCLUSIONS
Chapter 1. Asthma is a common respiratory disease that a ects 334 million people of all ages worldwide.1 Characteris cs of asthma are typical symptoms (wheezing, chest ghtness, shortness of breath), reversible airway obstruc on, bronchial hyperreac vity and chronic airway in amma on.2 Asthma has been regarded for a long me as a disease that develops in childhood. Gene c predisposi on, atopy and respiratory infec ons early in life have been established as the major risk factors for developing the disease.3, 4 The prognosis is generally considered favourable, up to 65% of children has “overgrown” their asthma when they are middle aged.5 However, since several decades a di erent asthma type that emerges in adulthood has been recognized, so called adult-onset asthma.6-9 This type of asthma is considered to have several dis nct clinical phenotypes, a more severe course than childhood asthma, with more symptoms and steeper decline in lung func on.10 However, the clinical course of adult-onset asthma over me is s ll largely unknown. Addi onally, eosinophilic airway in amma on plays an important role in the severity of the disease. Eosinophilia is associated with disease ac vity and can be used to tailor asthma therapy. Direct sampling of the airways is me consuming and costly. Therefore markers of eosinophilic airway in amma on have been described, whether these markers are in uenced by clinical asthma phenotype in adult-onset asthma is unknown.
The purpose of this thesis is twofold, rst: to examine the diagnos c accuracy of markers of eosinophilic airway in amma on, speci cally in di erent adult asthma phenotypes.
Secondly, identify predictors of asthma remission, increased asthma severity and exacerba ons in pa ents with recent-onset adult asthma in order to elucidate the course of the disease.
Chapter 2 summarizes the known prognos c factors of adult-onset asthma with respect to lung func on decline, increased asthma severity and asthma remission. Limited available data suggests that accelerated lung func on decline is associated with male gender, atopic status and poor baseline lung func on. Increased asthma severity is in uenced by smoking and low lung func on, whereas current uncontrolled asthma and smoking are associated with uncontrolled asthma in the future. High symptom scores, low lung func on and markers of airway eosinophilia can predict asthma exacerba ons. The remission rate of adult-onset asthma is considered to be low and mainly seen in pa ents with mild asthma and short disease dura on. Smoking has a profound nega ve e ect on asthma remission.
The number of longitudinal studies inves ga ng the course of adult-onset asthma is limited; many studies in this eld have been cross-sec onal or conducted in popula ons not speci cally consis ng of adult-onset asthma pa ents. In order to gain more insight in the prognosis of adults with newly diagnosed asthma and iden fy possible treatable factors, more prospec ve studies in this speci c group of pa ents are needed.
162