Severe asthma features in children: a case–control online survey
BACKGROUND
Very few studies have explored the distinguishing features of severe asthma in childhood in Europe, and only one study was conducted in Southern Europe. The aim of this study was to provide a detailed characterization of children with severe asthma treated in specialized pediatric asthma centers across Italy.


METHODS
We conducted a web-based data collection of family, environmental, clinical and laboratory characteristics of 41 patients aged 6-17 years with severe asthma, defined according to the recent guidelines of the European Respiratory Society and the American Thoracic Society, and 78 age-matched peers with non-severe persistent asthma. The patients have been enrolled from 16 hospital-based pediatric pulmonology and allergy centers in Northern, Central, and Southern Italy. Logistic regression analysis assessed the relationship between patients' characteristics and severe asthma or non-severe persistent asthma.


RESULTS
Features independently and significantly associated with severe asthma included lifetime sensitization to food allergens [Odds ratio (OR), 4.73; 95 % Confidence Interval (CI), 1.21-18.53; p = 0.03], lifetime hospitalization for asthma (OR, 3.71; 95 % CI, 1.11-12.33; p = 0.03), emergency-department visits for asthma during the past year (OR = 11.98; 95 % CI, 2.70-53.11; p = 0.001), and symptoms triggered by physical activity (OR = 12.78; 95 % CI, 2.66-61.40; p = 0.001). Quality-of-life score was worse in patients with severe asthma than in subjects with non-severe persistent asthma (5.9 versus 6.6, p = 0.005). Self-perception of wellbeing was compromised in more than 40 % of patients in both groups. Children with severe asthma had lower spirometric z scores than non-severe asthmatic peers (all p < 0.001), although 56 % of them had a normal forced expiratory volume in 1 s. No differences were found between the two groups for parental education, home environment, patients' comorbidities, adherence to therapy, exhaled nitric oxide values, and serum eosinophils and IgE .


CONCLUSIONS
As expected, children with severe asthma had more severe clinical course and worse lung function than peers with non-severe persistent asthma. Unlike previous reports, we found greater sensitization to food allergens and similar environmental and personal characteristics in patients with severe asthma compared to those with non-severe persistent asthma. Psychological aspects are compromised in a large number of cases and deserve further investigation.