Overview of asthma patients followed up in a tertiary clinic.

Background. Asthma is a disease that combines different biological mechanisms, inflammatory pathways, and phenotypic features. Our aim was to investigate the demographic and disease characteristics of patients with asthma and to reveal the distribution with different phenotypes according to endotype groups. Methods. Patients were identified as eosinophilic if the absolute eosinophil count was measured at least once ≥ 300/μL during the oral corticosteroid free period or ≥ 150/μL under oral corticosteroids. Patients sensitive to at least one inhalant allergen with skin prick test and/ or spIgE measurement were defined as allergic. They were categorized into four main endotypes. Results. Data of 405 asthma patients with a median age of 50.9 years were analyzed. The prominent clinical and phenotypic characteristics of the study group were being obese (43.2%) or overweight (32%), severe asthma (49.6%), adult-onset (56.1%) or late-onset asthma (35.3%). The distribution of the four main endotypes according to eosinophilic and/or allergic status, is as follows: 22.7% allergic-eosinophilic (AE), 27.9% nonallergic-eosinophilic (NAE), 22.9% allergic-noneosinophilic (ANE), 26.4% nonallergic-noneosinophilic (NANE). While most severe asthma patients were in the AE and NAE groups, those with early-onset asthma were in AE and ANE, and those with late-onset asthma were in the NAE and NANE groups. The proportion of uncontrolled patients was higher in the NAE group. Among the severe asthma patients, the rate of uncontrolled disease was higher in those with NANE asthma. Conclusions. Different phenotypes were more closely related to some endotypes. This may allow the clinicians to identify patients and predict appropriate treatment modalities and response for individualized care.