Abstract
BACKGROUND: Choosing effective devices (inhaled corticosteroid [ICS]-long-acting β2 agonist [LABA] combination inhalers) as maintenance treatment is critical for managing patients with asthma. We aimed to compare ICS/LABA combination efficacy, safety, and adherence across inhaler types and components in patients newly diagnosed with asthma. METHODS: Utilizing South Korea's National Health Insurance Service data, we conducted a population-based cohort study involving patients aged 18-80 years, newly diagnosed with asthma who received ICS/LABA combination therapy between January 2016 and December 2020. Outcomes assessed included treatment adherence, asthma exacerbations, hospitalizations, emergency-department visits, mortality, and safety outcomes within 3-month and 1-year post-index periods. RESULTS: Overall, 13,850 eligible patients were included, with subgroups categorized and compared according to inhaler type and component (metered dose inhalers [MDIs] vs. dry powder inhalers [DPIs], budesonide vs. fluticasone, and formoterol vs. salmeterol). Efficacy and safety profiles did not significantly differ across device types or ICS/LABA combination components during the 3-month and 1-year follow-up periods. However, the DPI group exhibited a significantly higher mean proportion of days covered (0.67 ± 0.23 vs. 0.62 ± 0.23; P < 0.001) and a lower risk of discontinuation (adjusted hazard ratio, 0.867; 95% confidence interval, 0.804-0.927; P < 0.001) than did the MDI group, with no significant differences observed between the other subgroups. CONCLUSIONS: The choice of inhaler device (MDI vs. DPI) and specific ICS/LABA combination components does not significantly impact efficacy and safety profiles in patients newly diagnosed with asthma. However, DPI use may be associated with improved adherence. These results provide valuable insights for clinicians in selecting appropriate and individually tailored inhaler therapies in real-world settings.