Factors Associated with Frequent Exacerbations in the UK Severe Asthma Registry

BACKGROUND: Frequent exacerbations are an important cause of morbidity in patients with severe asthma. OBJECTIVE: Our aim was to identify factors associated with frequent exacerbations in a large well-characterized severe asthma population and determine whether factors differed inpatients treated with and without maintenance oral corticosteroids (OCS). METHODS: Adults with severe asthma from specialized asthma centers across the United Kingdom were recruited to the UK Severe Asthma Registry. Demography, comorbidities andphysiological measurements were collected. We conducted univariable and multivariable logistic regression analyses to identify factors associated with frequent exacerbations, defined as 3 or more exacerbations treated with high-dose systemic corticosteroids in the past year. RESULTS: Of 1,592 patients with severe asthma from the UK Severe Asthma Registry, 1,137 (71%) were frequent exacerbators and 833 (52%) were on maintenance OCS. The frequent exacerbators were more likely to be ex-smokers, have gastroesophageal reflux disease, higher Asthma Control Questionnaire 6 (ACQ-6) score, and higher blood eosinophilia. Multivariable regression analyses showed ACQ-6 score greater than 1.5 (odds ratio [OR] 4.25; P < .001), past smoking history (OR 1.55; P = .024), and fractional exhaled nitric oxide greater than 50ppb (OR 1.54; P = .044) were independently associated with frequent exacerbations. Past smoking history correlated with frequent exacerbations only in patients on maintenance OCS (OR 2.25; P = .004), whereas ACQ-6 score greater than 1.5 was independently associated with frequent exacerbations in those treated with and without maintenance OCS (OR 2.74; P = .017 and OR 6.42; P < .001, respectively). CONCLUSIONS: Several factors were associated with frequent exacerbations in a large UK severe asthma registry population. High ACQ-6 score had the strongest association with frequent exacerbations irrespective of maintenance OCS status.(c) 2021 The Authors. Published by Elsevier Inc. on behalf of the American Academy of Allergy, Asthma & Immunology. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/). (J Allergy Clin Immunol Pract 2021;9:2691-701)