Early clinical remission and its role in lung function decline and exacerbation in adult Korean patients with asthma

Despite advancements in asthma management, many patients continue to experience poor disease control, lung function decline, and frequent exacerbations. Clinical remission (CR) has been proposed as a novel treatment target and surrogate marker for long-term outcomes. This study evaluates whether early CR at 1 year after inhaled corticosteroid (ICS) initiation influences lung function decline and exacerbation risk in asthma. This retrospective cohort study evaluated 492 asthma patients treated with ICS at two teaching hospitals. Patients were classified into early CR and non-early CR groups. Early CR was defined based on a composite set of criteria, including sustained absence of exacerbations, no systemic corticosteroid use, symptom control and stable or improved lung function in the first year following ICS initiation. Study outcomes were the annual forced expiratory volume in one second (FEV1) decline and the moderate-to-severe exacerbations. Early CR was significantly associated with slower annual FEV1 decline (4-component CR, adjusted β=31.6 mL/year, p=0.001; 3-component CR, adjusted β=15.7 mL/year, p=0.043). The benefits of early 4-component CR on attenuating annual FEV1 decline were more pronounced in specific phenotypes, including type-2 high asthma, persistent airflow limitation, severe asthma and patients requiring add-on long-acting muscarinic antagonists. Early 4-component CR had a reduced risk of moderate-to-severe (adjusted HR (aHR)=0.591, p=0.011) and severe exacerbations (aHR=0.508, p=0.025). Achieving CR within 1 year of ICS initiation was associated with improved lung function preservation and reduced exacerbation risk. These findings suggest the importance of achieving early CR as a clinical target in asthma management.