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.