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Using child reported respiratory symptoms to diagnose asthma in the community
  1. I T S Yu,
  2. T W Wong,
  3. W Li
  1. Department of Community & Family Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
  1. Correspondence to:
    Dr I T S Yu
    The Chinese University of Hong Kong, Department of Community & Family Medicine, Room 422, School of Public Health, Prince of Wales Hospital, Shatin, New Territories, Hong Kong;


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

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