Article Text
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.
- asthma
- respiratory symptoms
- likelihood ratio
- predictive values
- diagnosis
- CI, confidence interval
- FEV, forced expiratory volume
- FVC, forced vital capacity
- NLR, likelihood ratio for negative result
- NPV, negative predictive value
- PLR, likelihood ratio for positive result
- PPV, positive predictive value