Asthma control in the United States: relationships between short-acting β2-agonist and systemic corticosteroid use

Background Asthma control assessment is based on impairment (current symptoms) and risk (exacerbation history). Objective To understand the extent of uncontrolled asthma, we assessed relationships between prescription fills for systemic corticosteroids (SCS) and short-acting ß2-agonists (SABA) as risk and impairment markers, respectively. Methods Annual SCS and SABA fills among US patients with asthma were evaluated by a retrospective analysis of IQVIA Longitudinal Access and Adjudication Data. Patient severity was assigned based on GINA step-therapy level. Exacerbations were evaluated by SCS fills within 12 months of a first asthma prescription fill. Uncontrolled asthma was defined as ≥2 SCS and/or ≥3 SABA fills annually. Individual patient relationships between SCS and SABA fills were assessed by Pearson's correlation coefficient. Results 4,506,527 patients were included: 15% had ≥2 SCS fills, 29% had ≥3 SABA fills, 37% fulfilled either or both criteria. If only SCS were assessed, 22% treated as mild-to-moderate and 27% as severe asthma would have been misclassified as controlled. If only SABA use was evaluated, 8% treated as mild-to-moderate and 11% as severe asthma would have been misclassified. Overall, 81% of uncontrolled asthma occurred in patients treated for mild-to-moderate disease. Among patients with ≥2 SCS fills, mean SABA fills were 2.9; the correlation between SCS and SABA fills per patient was significant but weak (r=0.18; p<0.001). Conclusion High symptom burden and SCS exposures are not limited to severe asthma but are also characteristic in patients treated for mild-to-moderate disease. Both impairment and risk assessments are required to understand the full extent of uncontrolled asthma across disease severities.