Is It Necessary to Re-Evaluate Airway Hyperresponsiveness During Treatment of Mild Asthma? / 대한내과학회지

ABSTRACT

BACKGROUND/AIMS: Airway hyperresponsiveness (AHR) is one of the typical characteristics of asthma. However, its natural course is unknown. The presence of AHR is often not assessed in asthmatics undergoing medical treatment. We investigated the changes of AHR as compared with clinical parameters in patients with mild asthma. METHODS: We enrolled patients who were diagnosed with asthma, but were asymptomatic for > 3 months while undergoing medical treatment. AHR was measured using a methacholine bronchial provocation test after a 2-week washout period. AHR-negativity was defined as a PC20 > 25 mg/mL. Clinical parameters were retrospectively compared between the AHR-negative and -positive patients. RESULTS: Among 54 patients, 22 (40.7%) were AHR negative. Factors associated with the maintenance of AHR were male sex, presence of dyspnea, and high-dose inhaled corticosteroid plus long-acting beta agonists at initial presentation (respectively, p < 0.05). Age, symptoms other than dyspnea, blood tests, results of spirometry, diagnostic methods at presentation, and time from diagnosis to follow-up testing were not significantly different between AHR-negative and AHR-positive patients. Multivariate analyses failed to show a significant difference between the two groups, except for male sex (p = 0.014). CONCLUSIONS: Approximately 40% of patients with mild asthma show no AHR or clinical remission of the disease. Male sex may be a predictive factor for persistent AHR. However, altered AHR status is not predictable in patients with mild asthma undergoing medical treatment. Therefore, the cessation of regular controller might be advocated, and reassessment of AHR should be mandatory.