Analysis of Follow-up Results of Mannitol Challenge Test in Asthma Patients

Background: Asthma is characterized by chronic inflammation associated with airway hyperresponsiveness (AHR) which is measured using bronchial challenge testing. Mannitol as an indirect challenge has showed better reflect the complex effects of inflammation compared with direct challenges, and which is simple, safe, and more practical to use. Following airway hyperreactivity may be a useful strategy in asthma management because hyperreactivity may be abnormal even in patients with mild asthma and normal lung function. Airway hyperreactivity may better reflect airway inflammation and risk for deterioration than dose lung function or asthma symptoms. We investigated to analyze the follow-up results of mannitol challenge tests in asthma patients.

Methods: A total of 59 asthmatics repeated mannitol tests at Dong-A university hospital from May 2010 to February 2015. We compared the clinical characteristics between negative conversion and persistent AHR group.

Results: Fifty-three (89.9%) showed AHR to mannitol at initial test, 28 (47.5%) of whom had no AHR (negative conversion, groupⅠ) and 25 (42.4%) had persistent AHR (group II) at follow-up test. Six had no AHR at initial test, 2 had response to mannitol at follow-up test. There were no significant differences in sex, age, smoking habits, levels of eosinophil of serum and sputum, and baseline lung function. A longer duration of asthma and high frequency of asthma exacerbation was observed in group IIthan in group Ⅰ, while the proportion of atopy and steroid-naïve patients were higher in group Ⅰ. Total IgE and sputum eosinophil was much more decreased in group Ⅰ compared with group II.

Conclusions: In this study, 42.4% of asthma patients showed persistent AHR to mannitol. The negative conversion group of AHR may be associated with atopy, history of no ICS use, and improving of eosinophilic inflammation.