Abstract

Aims: To study how respiratory symptoms reported by children, with or without spirometry, could help to discriminate those with asthma from those without.

Methods: Respiratory symptoms (frequent cough, frequent phlegm, and wheezing) reported by 1646 schoolchildren (aged 8–12 years) in a respiratory questionnaire and the FEV₁:FVC ratio measured with spirometry (at three different cut-off values of 0.70, 0.75, and 0.80) were compared against the criterion standard of a physician diagnosis of asthma reported by the parents.

Results: The overall prevalence of asthma was 6%; more boys had asthma. Wheezing had the best discriminating ability among the three symptoms and a cut-off point at 75% was best for the FEV₁:FVC ratio. Combining wheezing with an FEV₁:FVC ratio <75% gave the highest discriminating ability of 83%. If the tests were applied to hypothetical populations with higher prevalence ratios of asthma, the added value of the FEV₁:FVC ratio became less apparent.

Conclusion: Respiratory symptoms, especially wheezing, reported by children had good discriminating ability for asthma and could be adopted for opportunistic screening in the primary care settings.