Impact of Health Insurance Type on Access to Biologics and Systemic Corticosteroid Exposure in Patients With Severe Asthma: A Real-World Study From the Korean Severe Asthma Registry (KoSAR)

Purpose: The impact of socioeconomic status on asthma control has been widely investigated. However, evidence regarding the impact of health insurance type on biologic utilization and systemic corticosteroid (SCS) exposure among patients with severe asthma remains limited. This study aimed to evaluate the associations between health insurance type, biologic utilization, and SCS dose in South Korea. Methods: Data from the Korean Severe Asthma Registry (KoSAR) between March 2022 and October 2023 were analyzed. Patients were categorized into 4 different groups based on their health insurance type: National Health Insurance (NHI) with private health insurance (PHI), NHI-only, and Medical Aid (MA) with PHI, and MA-only. Results: Among the 578 patients with severe asthma, 327 (56.6%) were classified as NHI+PHI, 192 (33.2%) as NHI-only, 22 (3.8%) as MA+PHI, and 37 (6.4%) as MA-only. Decline in lung function, asthma exacerbations, and impaired quality of life were significantly more prevalent in the MA+PHI and MA-only groups. Overall, 159 patients (27.5%) were identified as biologic users. The most frequently prescribed biologics were dupilumab (8.8%), reslizumab (8.5%), omalizumab (7.1%), followed by mepolizumab (2.3%). Biologic utilization varied significantly by insurance type, with rates of 30.9% in the NHI+PHI group, 27.1% in the NHI-only group, and only 8.1% in the MA-only group (P = 0.011). Conversely, dependence on SCS (defined as SCS use for more than one month) showed an inverse pattern, being most prevalent in the MA-only group (52.6%), followed by the NHI-only group (36.8%) and the NHI+PHI group (26.7%) (P = 0.017). Conclusions: Our study showed that differences in biologic and SCS use were associated with insurance type. These findings suggest that insurance coverage and out-of-pocket expenses are important factors influencing access to optimal care for severe asthma, emphasizing the need for policy interventions to promote health equity.