RATIONALE: Studies have shown that approximately 40-60% of patients have uncontrolled asthma. Yet the number of those with maximized inhaler maintenance therapy who remain uncontrolled and may be candidates for biologic agents, is not known. This study assessed the level of asthma control among patients seeking care in pulmonary and allergy clinics to determine the percent who may be eligible for biologic therapy.
METHODS: A multisite, cross-sectional study was conducted between January 21 and April 29, 2019. Participants aged ≥18 were recruited from 24 pulmonary and allergy clinics in the U.S. Eligible participants presented to specialists’ office for a previously scheduled visit, had a physician diagnosis of asthma, and used ≥1 ICS-containing maintenance therapy within the past 4 weeks; with no history of COPD, chronic bronchitis or emphysema. Patients completed an electronic questionnaire, including demographics, medical history, current asthma treatment, health resource use, the Asthma Control Test (ACT) and St. George’s Respiratory Questionnaire. Asthma control was defined as ACT score ≥20 “Well Controlled” and ACT ≤19 “Not Well Controlled”. Surveys were supplemented with chart abstraction data. Eligibility for biologic therapy was measured using 2 definitions: (1) Use of medium/high dose ICS/LABA +/-LAMA and no biologics in past 4 weeks with ≥2 exacerbations in the past 12 months, (2) same criteria, but having one measurement denoting blood eosinophil count ≥150 cells/µL in past 12 months.
RESULTS: 774 patients participated in the study with mean (SD) age 54.5 (16.2) years and 74.2% female. 479 (61.9%) patients reported use of medium/high dose ICS/LABA in the past 4 weeks, and 147 (of 229 patients with eosinophil measurements) had a blood eosinophil count ≥150 cells/µL within the last 12 months. Using Definition #1, 156 patients had medium/high dose ICS/LABA and ≥2 exacerbations, resulting in 20.2% of the total study population eligible for a biologic; among these, 72.4% were not well controlled. Applying the blood eosinophil criteria for Definition #2, 45 patients or 19.7% of the study population with eosinophil measurements met the criteria for therapy, exacerbations and eosinophil level, with 66.7% (n=30) uncontrolled.
CONCLUSION: Under a specialist’s care, 19.7-20.2% of the total asthma study population with maximal inhaler therapy and continued exacerbations met eligibility criteria for a biologic therapy, and among those 66.7-72.4% were uncontrolled. These findings suggest the need for clinicians to routinely assess control and peripheral eosinophil blood counts among all patients, including those treated with medium/high dose ICS/LABA.
