Aims: To ascertain whether the severity of childhood asthma can be reliably assessed by simple clinical features, 94 newly diagnosed, school-aged asthmatic children were investigated. Methods: The study included parental interviews, physical examination, skin prick tests, lung function studies, including a brief visual interpretation of the flow-volume curve, and a 6-min exercise challenge test on a treadmill, which was used as a reference. Results: Baseline lung function studies showed a concave-shaped flow-volume curve in 40 (43% ) patients, reduced maximal mid-expiratory flow (MMEF) in 25 (27% ) and a reduced ratio of forced expiratory volumein 1 s to forced vital capacity (FEV1/FVC) in 14 (15% ). The drop in peak expiratory flow (PEF) after exercise ranged from 0 to 79% of the baseline (mean 21.3% ) and exceeded 12.5% in 52 (55% ) patients. There was a small but significant correlation between the baseline FEV1/FVC and MMEF values and the response to exercise (r=-0.39 and -0.35; p=0.001, respectively), but when studied by linear regression analysis, the response to exercise was best predicted by the past symptom rate and a concave pattern in the pre-test maximal expiratory flow-volume curve. The values of traditional lung function tests or age, atopy, duration of symptoms or history of exercise-induced wheezing did not remain in the model. Conclusions: These results show that the severity of asthma in school-aged children can be predicted at the first visit based on the past rate of symptoms and a visual interpretation of the maximal expiratory flow-volume curve.
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