D3.133 - Clinical Impact of Cumulative Oral Corticosteroid Exposure in Patients with Severe Asthma: Data from the Korean Severe Asthma Registry

A major burden of severe asthma is frequent exacerbations or uncontrolled symptoms requiring long-term oral corticosteroids, which are associated with adverse effects and poor outcomes. Despite advances in biologic therapies, a substantial proportion of severe asthma patients continue to rely on oral corticosteroid (OCS) in real-world practice. This study aimed to assess 1-year cumulative OCS exposure and compare clinical characteristics between high and low OCS users in severe asthma using the data from the Korean Severe Asthma Registry (KoSAR).

Patients with ≥12 months of follow-up in KoSAR were classified into high and low OCS exposure groups based on the upper quartile of cumulative annual OCS dose, and group comparisons were performed using t-tests and chi-square tests.

A total of 477 patients were eligible for this study, and the mean cumulative dose of OCS (prednisolone equivalent dose) was 1,055.64 ± 1,474.28 mg. Patients were stratified into high OCS exposure (upper quartile; ≥1,255 mg, n=119) and low OCS exposure groups (n=358). The prevalence of diabetes mellitus, ischemic heart disease, and fractures was significantly higher in the high OCS group compared with the low OCS group (P=0.036, P=0.010, and P=0.006, respectively). Medical aid insurance coverage was more common in the high OCS group (P=0.005).

Lung function parameters such as FEV1, FEF 25-75, and FEV1/FVC were significantly lower in high OCS group (median FEV₁ %pred: 61.5% vs. 68.1%, P<0.001; FEF₂₅–₇₅: 0.86 vs. 1.24 L/s, P=0.007; FEV₁/FVC: 64% vs. 70%, P<0.001). The use of triple therapy and macrolides was more frequent in high OCS group; however, the use of biologics was significantly lower in high OCS group. During the 12-month follow-up, moderate to severe exacerbation rate was substantially increased in the high OCS group but not in low OCS group (4.41±5.20 vs 2.24±3.83, P<0.001), nonetheless the cumulative OCS dose or biologics during follow-up did not differ significantly between the two groups. 

Cumulative OCS exposure remains high in patients with severe asthma and is associated with metabolic and cardiovascular comorbidities, reduced lung function, and increased exacerbations. These findings highlight the need for optimized management strategies, including appropriate biologic use and careful management of OCS-related comorbidities.