Lung function and asthma symptoms in children: relationships and response to treatment.

Abstract

The aim of this study was to determine the relationships between the forced expiratory volume in 1 s (FEV1), peak expiratory flow (PEF) and asthma symptom scores, as well as their response to treatment, in children with no recent exacerbations of asthma. Asthma symptom scores, FEV1 and PEF were characterised, and their relationships and changes at follow-up studied in 64 children (mean age 9.5 y) referred to asthma outpatients. The mean FEV1 and PEF at the initial clinic visit were 94% of predicted values. At follow-up, mean FEV1 and PEF were similar. However, symptom scores (maximum obtainable score for each variable = 3) for exercise, nocturnal cough and morning cough were abnormal at the initial visit (mean +/- SD, exercise 1.0 +/- 0.7, nocturnal cough 1.7 +/- 1.2, morning cough 1.6 +/- 1.2) and improved significantly at follow-up (exercise 0.8 +/- 0.7, nocturnal cough 0.9 +/- 1.1, morning cough 1.0 +/- 1.2) (p < 0.05). A significant relationship was not observed between lung function and total symptom score, at either the initial or follow-up clinic visit. Neither FEV1 nor PEF significantly correlated with individual symptom scores. While symptom control improved, no significant relationships between change in asthma symptom scores and change in FEV1 and PEF between the initial and follow-up visits were observed. Clinic ("office") spirometry, currently performed world-wide, cannot be uniformly regarded as an indicator of asthma status. In addition to the measurement of lung function, quantitative symptom scoring may be a helpful tool for physicians in the assessment of childhood asthma status.