A doctor's ability to assess the severity of childhood asthma by simple clinical features

Abstract

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. 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. 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 volume in 1 s to forced vital capacity (FEV(1)/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 FEV(1)/FVC and MMEF values and the response to exercise (r=-0.39 and -0.35; p=0.000, 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. 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.