Background: Severe asthma is recognized in the European Respiratory Society/American Thoracic Society guidelines as a major unmet need in the management of asthma.
Objective: The study objective was to describe the clinical burden of Global Initiative for Asthma (GINA) steps 4-5 asthma for patients treated by specialists in the U.S. community setting.
Methods: Patients, ages ≥12 years, with asthma who received GINA step 4 or 5 treatment and were treated at a large U.S. allergy practice network between January 1, 2010, and April 30, 2016, were retrospectively identified by using electronic health records. Clinical outcomes included lung function (forced expiratory volume in one second of expiration [FEV1] and FEV1% predicted), symptom control (Asthma Control Test [ACT]), the fractional exhaled nitric oxide (FeNO) value (FeNO ≥25 ppb indicates airway inflammation), and asthma medication use. The change in outcomes from baseline to 12 and 24 months after the index date was calculated.
Results: Of 120,116 patients with asthma, 12,922 (10.8%) had severe asthma, 68% (n = 8751) while on step 4 therapy. The mean baseline prebronchodilation FEV1% predicted was 79.7%, and the mean baseline ACT score was 17.0. With uncontrolled asthma defined as an ACT score of ≤19 and/or an FEV1 value of <80% predicted and/or oral corticosteroid use of ≥2 bursts, 52.5% and 57.7% of patients on step 4 and step 5 therapy, respectively, had uncontrolled asthma at baseline. Of a subset of patients, 40.9% had an eosinophil count of ≥300 cells/mm3 and 44% had an FeNO concentration of ≥25 ppb. Small increases in the FEV1 value were observed from baseline to 12 months (n = 4022) and 24 months (n = 2326) postindex (0.07 and 0.04 L, respectively).
Conclusion: A considerable proportion of patients had uncontrolled asthma while on current GINA steps 4-5 treatment, which indicated that additional therapies may be required to reduce the clinical burden of severe asthma.