Lung function and symptom perception in children with asthma and their parents

A large proportion of children with asthma are managed without recourse to specialized care, and treatment decisions are based solely on symptoms as reported by the children and their parents. We investigated 90 school-age children with the diagnosis of asthma and their accompanying parent to evaluate whether we can obtain better information by using three different means of asking for asthma symptoms: a questionnaire for children (QSR(children)), "smilies," and a visual analogue scale for children (VAS(children)). Furthermore, we analyzed the relationship between these symptom reports and lung function results. Finally, we attempted to determine whether performing a lung function test contributes relevant information toward improving asthma management. Multiple linear regression adjusted for age and gender showed a significant relationship between VAS for children and forced expiratory volume in 1 sec (FEV(1)) (P = 0.047) and maximal expiratory flow at 50% of forced vital capacity (MEF(50)) (P = 0.037). Neither age, gender, QSR for children, "smilies for children" nor all the parents' scores showed a significant association with lung function measurement in the regression model. Subgroup analysis with Spearman's rank correlation coefficients by age group revealed significant correlation in children <10 years between VAS for children, QSR for parents, smilies for parents, and the lung function parameters FEV(1), and MEF(50). Above age 10 years there was no correlation at all, with the accuracy correlation ranging from -0.04 to +0.21. Our data demonstrate that reported symptoms do not reliably correlate with lung function results in asthmatic children and the childrens' parents, and correlation is dependent on the instrument used for symptom evaluation. In children, the VAS, and in parents, the QSR were the most valuable means of obtaining best information on asthma symptoms. This underlines the importance of supplementing information on asthma symptoms with lung function measurements to more reliably assess the severity of asthma.