Breathlessness perception assessed by visual analogue scale and lung function in children with asthma: a real-life study.

Background: In children with asthma, discrepancies between objective indicators of airway obstruction and symptom perception are often observed. Although visual analogue scale (VAS) has been proposed as a useful tool for assessing accurate symptom perception, previous studies conducted in children with asthma included only small cohorts. A study was therefore designed to investigate the usefulness of VAS in establishing a reliable relationship between breathlessness perception and lung function in a large cohort of children with clinical diagnosis of asthma.

Methods: A total of 703 children [470 boys and 233 girls, median age 10.29 (8.33-12.58) yr] with asthma were included in this cross-sectional, real-life study. Perception of breathlessness was assessed by using VAS, and lung volumes and expiratory flows were measured by spirometry.

Results: Most children had intermittent or mild persistent asthma (93.3%), and only 46 children had a significant bronchial obstruction defined by FEV(1) values <80% of predicted. Globally, VAS was significantly, even though weakly, related to lung function. Analyzing children with bronchial obstruction, a moderate relationship between both FEV(1) (r = 0.47) and FEF(25-75) (r = 0.42) and VAS was detected. A VAS value of 6 was found to be a reliable cutoff for discriminating children with bronchial obstruction (AUC 0.83 at ROC curve; OR 9.4).

Conclusion: The present study demonstrates that VAS might be considered a useful tool to assess symptom perception, mainly in children with airflow limitation.