Prognosis of Adult Asthma After Normalization of Bronchial Hyperresponsiveness by Inhaled Corticosteroid Therapy

Background: Inhaled corticosteroids (ICSs) are the most effective anti-inflammatory drugs for adult asthma and can improve not only clinical symptoms but also bronchial hyperresponsiveness (BHR). However, the prognosis of adult asthma has not been well studied, and it remains to be elucidated precisely how long treatment with ICSs should be continued once clinical remission is achieved. Objectives: We examined whether ICS use could be withdrawn or reduced without exacerbation of disease. Methods: We retrospectively studied 374 adult patients with asthma to determine which factors predicted the elimination or reduction of ICS treatment without exacerbations of disease after the achievement of normalized BHR to acetylcholine. The patients were classified into three groups: Group 1 had symptoms within 6 months of normalization and needed to continue therapy; group 2 received the equivalent of ≥ 400 μ g fluticasone propionate until BHR normalization, did not have symptoms in the 6 months after normalization, and then had their doses of ICSs halved; and group 3 received the equivalent of ≤ 200 μ g fluticasone propionate at an enrollment, did not have symptoms in the 6 months after normalization, and then had all ICSs withdrawn. The primary outcome measure was the presence of clinical symptoms. We used multiple logistic regression and a Kaplan-Meier analysis to analyze the factors predicting remission. Results: Twenty-nine patients in group 3 remained asymptomatic for more than 30 months (mean 47.1 ± 12.4 months) after discontinuing ICS therapy. The predictive markers of remission were low levels of eosinophils in the sputum, high %V₅₀ at the first hospital visit, and the need for only a low daily dose of ICS to induce normalized BHR. Conversely, patients with severe BHR at the first hospital visit, low %FEV₁ at normalized BHR, and a need for high-dose ICSs to reach normalized BHR could not reduce or discontinue treatments. Conclusion: Some adult patients with asthma whose BHR is normalized by ICS therapy can achieve remission from disease exacerbation after discontinuation of ICSs. However, patients with severe asthma or asthma of long duration may not achieve remission even if their BHR is normalized.