Page 113 - ADULT-ONSET ASTHMA PREDICTORS OF CLINICAL COURSE AND SEVERITY

CLINICAL PREDICTORS OF REMISSION AND PERSISTENCE OF ADULT-ONSET ASTHMA
DISCUSSION
This study shows that one in six pa ents with adult-onset asthma experiences clinical remission within the rst 5 years of the disease, which is more than previously reported. Independent risk factors of asthma persistence include moderate to severe bronchial hyperresponsiveness and nasal polyposis, which together reduce the chance of asthma remission to less than 1%. These results demonstrate that asthma severity - de ned by BHR - and upper airways involvement at the me of asthma diagnosis are major outcome determinants of newly diagnosed asthma in adults.
In the present study we found an asthma remission rate of 3.2% per year, which is rela vely high. In the literature, a wide range of remission rates in adults with asthma has been reported varying from 0.6 to 3% per year.6, 8, 10, 25, 26 An important problem when comparing these gures with those from our study is the lack of a common de ni on of asthma remission. Furthermore, most studies have not di eren ated between childhood and adult-onset asthma, which most likely caused an overes ma on of the remission rate.
Few studies speci cally addressed remission rates in adult-onset asthma and only one study exclusively included pa ents with new-onset adult asthma.9 The la er study found a clinical remission rate of 0.8% per year, which is considerably lower than in our study. Even a er applying more strict rules for remission, by including normal lung func on and absence of airway hyperresponsiveness, the remission rate was s ll higher than previously reported (Figure 3).9 This discrepancy might be due to di erences in asthma severity of the pa ents, although this is not likely. All our pa ents were recruited from secondary or ter ary care centres, and diagnosed with asthma by pulmonologists, which was con rmed by spirometry or airway hyperresponsiveness tests. One retrospec ve study suggested that remission rates were rela vely high early a er disease onset, and decreased a er 4-7 years,6 which is in line with our ndings, and might explain the rela vely high remission rates a er the rst 5 years of the disease.
Our study was set up to iden fy predictors of remission and persistence of new onset asthma in adults. Two previously published studies on this topic9, 13 reported that there were di erences between pa ents who remi ed and not remi ed (e.g. with respect to baseline FEV1), but the number of pa ents with remi ed asthma in those two studies was too low to properly analyze that point. Our study had enough remi ed pa ents for more detailed sta s cal analysis and we found that airway hyperresponsiveness and nasal polyposis were strongly associated with asthma persistence but not lung func on at baseline. In fact, all pa ents with nasal polyps showed asthma persistence. The importance of nasal polyposis in determining the persistence of asthma is a novel nding. Previous studies have shown a close associa on between upper airways involvement and asthma.27, 28 Allergic and non-
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