Severity predictors of different phenotypes of T2 asthma endotype

Abstract

BACKGROUND: Epidemiological studies have showed that severe asthma is observed in 5–10% of patients. It is considered as a major social and economic burden for the healthcare system. AIM: to perform a comparative analysis of clinical features of allergic and non-allergic phenotypes of T2 asthma and determine the most important predictors of severity. MATERIALS AND METHODS: We studied 150 patients with asthma (ages 18–65). Of these, 61 were diagnosed with T2 endotype of asthma. Clinical examination and allergy testing were performed. The potential predictors of severe asthma included: asthma phenotype, gender, age (including elderly age), daytime/nocturnal symptoms per week, asthma exacerbations that required systemic corticosteroid therapy and hospitalisations, the volume of forced exhalation in the first second (FEV1; % of predicted value), body mass index (kg/m2), concomitant diseases, smoking status, sensitization to non-infectious allergens and blood eosinophil count. RESULTS: Group 1 included 34 patients with allergic phenotype of asthma, group 2 ― 27 patients with non-allergic phenotype of T2 endotype of asthma. Univariate analyses revealed that subjects with non-allergic asthma were likely to have severe asthma (OR=3.14 [95% CI: 1.09–9.58]. Increased daytime symptoms per week, nocturnal symptoms per week, exacerbations that require systemic corticosteroids and hospitalisation were associated with asthma severity (OR=1.05 [95% CI: 1.01–1.11], 1.21 [95% CI: 1.05–1.45], 3.46 [95% CI: 1.68–10.19], 4 [95% CI: 1.75–12.32] and 4 [95% CI: 1.75–12.32], respectively), regardless of the disease phenotype. Lower FEV1 was associated with severe asthma (OR=0.96 [95% CI: 0.93–0.99]. Multivariate analysis showed that age, increased frequency of nocturnal symptoms, and lower FEV1 were associated with severe asthma. CONCLUSION: The certain clinical differences of allergic and non-allergic asthma could be revealed when analyzing anamnestic data and clinical findings. Increased frequency of nocturnal symptoms, decreased FEV1 and age are the most significant predictors of severe T2 endotype of asthma.