The Role of Inflammatory Phenotype in Patients With Exacerbation-prone Asthma and Ongoing Therapy

Abstract

Introduction: The risk factors for having frequent exacerbations are not well documented in cohort studies of patients with asthma on existing therapy. The objective of the present study was to compare the clinical and inflammatory characteristics of patients with exacerbation-prone asthma (EPA) with a history of two or more exacerbations in the previous year with those who had presented just one or no exacerbation.

Methods: An ambispective observational study was conducted in a tertiary hospital. Patients diagnosed with moderate or severe asthma and ongoing therapy, whose inflammatory profile was determined by means of allergy and atopy status, blood eosinophilia and induced sputum were included. Patients were classified according to the number of asthma exacerbations in EPA (≥2 exacerbations in the previous year) vs. non-exacerbators (≤1 exacerbation in the previous year). Clinical, lung function and inflammatory characteristics of the two groups were compared.

Results: Three hundred ten patients were visited in the Asthma Unit in 2018 and the combination of atopy and allergy status, blood eosinophilia and induced sputum was obtained in 96 (31%) patients. Of this latter group, 46 patients (47%) presented EPA compared to 50 (53%) non-exacerbators. Airway and blood eosinophilic inflammation did not differ between EPA and non-exacerbators in patients with asthma and ongoing therapy, and it was not a risk factor for EPA in our cohort.

Conclusion: Airway or blood type 2 inflammation status is not a valid tool for recognizing EPA or predicting asthma exacerbations in asthma patients following controller therapy.

Keywords: Asthma; Asthma exacerbation; Induced sputum; Inflammatory phenotype; Severe asthma; Type 2 inflammation.