To describe the demographic and clinical characteristics, including the extent of T2 phenotype, in five groups of patients with severe asthma, including those who do not initiate a biologic when eligible, and do not initiate and are not eligible, and between those who initiate: those who stop, switch, or continue the initial biologic.
To assess the clinical outcomes (e.g. reduction of exacerbations, long-term OCS use, total OCS dose, asthma control) by biologic utilization patterns.
To assess healthcare resource utilization (hospitalization, emergency room visits, invasive ventilation) by biologic usage patterns (not initiating, stopping, switching or continuing).