Future Risk After Achieving Clinical Remission in Patients with Severe Asthma: A Comparison of Different Definitions

Background: Clinical remission (CR) has recently been recognized as an important treatment goal in severe asthma. However, there is no consensus on its definition. Objectives: We aimed to evaluate differences in the rates of CR based on various definitions and to investigate the extent to which exacerbations, lung function decline, and sustained CR are observed over 12 months after evaluating CR, to identify the best definition reflecting future risks. Methods: Severe asthmatic patients receiving biologic therapy (n = 52) were retrospectively evaluated for 24 months according to three previously reported CR definitions incorporating oral corticosteroid (OCS) use, exacerbations, symptoms, and lung function. Results: Over 24 months, significant improvements were observed in all clinical parameters. At 12 months, the CR rates according to the three definitions ranged from 26.9% to 40.4%. At 24 months, sustained CR was achieved in 17.6% to 29.4%. Two of the three definitions (CR (no OCS use, no exacerbations, and well-controlled asthma (ACT ≥ 23) and CR (no OCS use, no exacerbations, ACT ≥ 20, and ΔFEV₁ ≥ 100 mL from baseline)) predicted a reduced risk of future exacerbations. Annual FEV₁ decline did not differ between CR and non-CR groups, regardless of the three definitions. Conclusions: Defining CR based on three components-no OCS use, no exacerbations, and well-controlled asthma (ACT ≥ 23)-may provide prognostic information for predicting future exacerbation risk in severe asthmatic patients receiving biologic therapy.