The profile of severe asthmatics: Results from a specialized asthma clinic

In patients with severe asthma, individualized treatment, and appropriate phenotyping are required to achieve control. In our study, our aim was to examine the characteristics of a specific patient group in a specialized tertiary asthma outpatient clinic, which is the primary setting for evaluating severe asthma patients, with the intention of obtaining national data. In this cross-sectional observational study, sociodemographic, clinical presentations, laboratory results, and spirometry measurements of patients with severe asthma who were followed up in our specialized asthma outpatient clinic for at least one year were recorded. Patients were defined as eosinophilic if they had a blood eosinophil count of 300/µL or higher at least twice during the oral corticosteroid free-period or 150/µL or higher under oral corticosteroids as allergic if they had sensitization to at least one inhalant allergen consistent with their history. Overall, 201 severe asthma patients (74.1% female) with a median disease duration of 15 (min-max= 1-49) years and a median follow-up duration of 7 (min-max= 1-40) years were analyzed. Most of the patients (56.7%) had adult-onset asthma [median age of onset was 32 (min-max= 10-62) years]. Overweight and obese patients were in the majority (31.8%, and 41.8%, respectively) and the median body mass index was 29 (min-max= 17.5-49.5). More than half of the patients (55.2%) had controlled asthma and the median Asthma Control Test score at the last visit was 23. Biologic therapies were applied to 73.1% (n= 147) of the patients [60.5% (n= 89) omalizumab, 39.5% (n= 58) mepolizumab]. Half of the group was allergic (49.3%) and three-quarters of them were eosinophilic (72.1%). Allergic patients had earlier asthma onset and had more controlled disease than nonallergic ones. Eosinophilic patients were younger and less obese than noneosinophilic patients. Obese and late-onset asthmatics had more uncontrolled disease than normal weight subjects and early onset patients. The high rate of disease control in the patients with severe asthma in the current study demonstrated the importance of targeted individualized therapy with accurate phenotyping in specialized asthma outpatient clinics.