Page 173 - ADULT-ONSET ASTHMA PREDICTORS OF CLINICAL COURSE AND SEVERITY

type 2 in amma on in the airways, resul ng in an in ux of neutrophils. Also inducing basal membrane thickening and mucus hypersecre on by goblet cells.61 These e ects all contribute to cor costeroid insensi vity and increased symptom burden.
POTENTIAL BIAS
One poten al pi all for research on adult-onset asthma is the risk of recall bias; how sure are pa ents about their asthma history? In order to select pa ents with real adult-onset asthma for the Adonis-study, extensive intake interviews about pulmonary complaints in childhood were done and strict inclusion and exclusion criteria were used. Furthermore, epidemiological studies have shown that the self-reported year of asthma onset appears to be rather accurate.62 Therefore we think that the chance of including pa ents with a relapse of remi ed childhood onset asthma is probably very low, but cannot be excluded.
As smokers cons tute an important and understudied subgroup of adult-onset asthma pa ents (up to one third is ac ve smoker63), we did include them in our study. However, asthma at older age is o en mistaken for COPD, especially when pa ent are (ex)smokers. To make sure these pa ents did not have COPD, strict lung func on criteria were used and pa ents were excluded if they had xed airway obstruc on and sings of emphysema.
The de ni on of asthma remission has been highly variable in di erent studies. We have chosen to use clinical remission, based on the absence of asthma symptoms and no medica on use. This de ni on might not be as strong as one including pathophysiological remission (normal lung func on, no bronchial hyperreac vity, absence of airway in amma on). Due to a limited number of pa ents with pathophysiological follow-up data, we were not able to do rm analysis on the whole cohort.
CLINICAL IMPLICATIONS
The results of our studies have several clinical implica ons. We have found a clear predic ve clinical pro le for asthma persistence, in which bronchial hyperreac vity and nasal polyps are the main determinants. Furthermore, the number of pack years smoked can be used to es mate the chance of an increase in asthma severity. With these clear clinical characteris cs, clinicians have tools to recognise pa ents at risk for persistent asthma and who are prone to deteriora on in an early phase. Clinical characteris cs combined with in ammatory markers like blood eosinophils and FeNO will give an even more accurate view on the phenotype of the pa ent in front of us.
The next step would be a therapeu c consequence for the clinical prognos c characteris cs. For pathological characteris cs like airway eosinophilia this has been shown previously (see Part 1). Treatment of chronic rhini s has been shown to improve asthma control.64 Whether aggressive treatment of nasal polyps in an early stage would improve asthma prognosis (no asthma or asthma remission) is unknown. Our observa onal data suggest a limited e ect, as two third of the pa ents with nasal polyps had already undergone surgical treatment and s ll
SUMMARY AND GENERAL DISCUSSION
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