Clinical remission of mild-to-moderate asthma: Rates, contributing factors, and stability

Background: Although clinical remission (CR) of severe asthma has been extensively investigated, CR of mild-to-moderate asthma remains unexplored. Objective: This study aimed to determine CR rates, contributing factors, and stability in patients with mild-to-moderate asthma. Methods: We retrospectively analyzed 263 patients with asthma. Three-component CR was defined as no exacerbation, no daily oral corticosteroid receipt, and an Asthma Control Test score equivalent to that of the well control; 4-component CR included these parameters plus forced expiratory volume in 1 second of ≥80% predicted. CR during the 1 year and stability of CR over 10 years were retrospectively analyzed in patients with mild-to-moderate and severe asthma. Results: The CR rates were significantly higher (4-component, 73.2%; 3-component, 81.0%) in patients with mild-to-moderate asthma compared with the CR rate in patients with severe asthma (4-component, 33.9%; and 3-component, 30.6%). A lower smoking index contributed to 3- and 4-component CR. Lower body mass index contributed to 3-component remission, and later onset and shorter asthma duration contributed to 4-component remission. In patients experiencing 4-component remission 10 years before, 80.3% maintained disease in remission; 89.1% of patients experiencing 3-component remission maintained disease in remission. In patients with disease that did not maintain 4-component CR after 10 years, predicted forced expiratory volume decreased, but no differences in inhaled corticosteroid and long-acting β-agonists/long-acting muscarinic antagonists receipt were detected between 10 years ago and the present. The current muscarinic antagonist receipt remained low, at 16.7%. Conclusion: CR, including normalized forced expiratory volume, is obtainable and sustainable in most Japanese patients with mild-to-moderate asthma. Assessing CR in these patients may help avoid undertreatment and reduce future risks.