Prevalence and clinical profile of difficult-to-control severe asthma in children: results from pneumology and allergy hospital units in Spain.

BACKGROUND Severe asthma is often poorly controlled and its prevalence in Spanish children is unknown. The aim was to determine the prevalence of difficult-to-control severe asthma in children, the agreement of asthma control between physicians and Spanish Guidelines for Asthma Management (GEMA), and the health-related quality of life (HRQoL) for children and parents. METHODS Observational, cross-sectional, two-phase, multicentre study. In the first phase, all children who attended pneumology and allergy units during a three-month period were classified according to physicians' criteria as patients with: asthma, severe asthma, or difficult-to-control severe asthma. Patients aged 6-14 years with severe asthma (difficult-to-control or controlled) were included in the second phase. RESULTS 12,376 asthmatic children were screened in the first phase. According to physicians' criteria, 8.8% (95% CI 8.3-9.3%) had severe asthma. Of these, 24.2% (95% CI, 21.7-26.8%) had difficult-to-control severe asthma. 207 patients with severe asthma (mean age 10.8 ± 2.3 years; 61.4% male; mean of 5.5 ± 3.4 years since asthma diagnosis) were included in the second phase. Compared to the patients with controlled asthma, children with difficult-to-control asthma had a higher number of exacerbations, emergency room or unscheduled primary care visits in the previous year (p<0.0001, all) and poor HRQoL (p<0.0001, both children and caregivers). 33.3% of patients with controlled asthma according to physicians' criteria were poorly controlled according to GEMA. CONCLUSIONS Around one in four asthmatic children with severe disease had difficult-to-control asthma, although one third was underestimated by physicians. Children with difficult-to-control severe asthma had a poor HRQoL that also affected their parents.