Assessment and prediction of asthma and its severity in the pediatric community

Abstract

Seventy four asthmatic children aged 7 to 11 years were examined along with controls matched by age and sex. Clinical and laboratory investigations preceded a 28-day follow-up where data about morning and evening peak expiratory flow rate (PEF), symptoms and treatment were recorded. The coefficient of variation of PEF was found to be an objective measurement of asthma severity that has statistically significant correlation with both symptoms (rs = .36) and treatment (rs = .60). Moreover, it separates mild and severe asthmatics, as confirmed by statistically significant differences (p = .008 or less) in symptoms, treatment, skin allergy and airways response to exercise. Skin allergy and airways responsiveness to exercise were found to be predictors of both disease and severity. By means of logistic regression analysis it was possible to establish the probabilities for both asthma and severe asthma when children presenting and not presenting these characteristics are compared. One single positive skin test represent a probability of 88% for the development of asthma and a probability of 70% for severe disease. A PEF reduction of 10% after an exercise test implies a probability of 73% for disease and a probability of 64% for severe disease. Increases in these variables imply geometrically increased risks and their presence together have a multiplicative effect in the final risk.

The respiratory effects of reduction of mite allergen in the bedrooms of asthmatic children — a double‐blind controlled trial

“…Essentially, children were diagnosed as asthmatic if they had wheezing with breathlessness in the last year. This one-year period prevalence of symptomatic asthma was found to be 12% which agrees with other recent surveys carried out in the Bristol area [12][13][14]. Seventy-five ofthe ^asthmatic' families had a repeat questionnaire administered 10 weeks after the first: 95% produced the same diagnosis.…”

“…This permitted us to proceed with the entry criteria for the trial and eventually produce the 70 subjects for randomization (Table 1). .Analysis ofthe questionnaire responses used the formula previously applied [12,14] to establish the diagnosis of asthma. Essentially, children were diagnosed as asthmatic if they had wheezing with breathlessness in the last year.…”

“…At the present time, the experimental trials of removal of mite allergen [lO.l 1) do not provide a consistent estimate ofthe therapeutic effect of this manoeuvre. The problem is important as community studies [12][13][14] show a 12% 1-year symptomatic period prevalence of asthma in schoolchildren in England and 70% of these children are significantly sensitive on skin testing to house dust mite [12]. In view ofthe paucity of evidence and the importance ofthe problem, a rigorously conducted scientific trial was necessary to establish if mite allergen removal is an effective therapeutic procedure in the community.…”

The relationship between mite allergen exposure and asthma severity

“…Similarly it was subsequently demonstrated that mite exposure increased the risk not only for asthma but also for atopic dermatitis [11]. We have also demonstrated that the severity of skin-test reactivity to house dust mite is an independent predictor of subsequent asthma severity [12]. The quantity of mite allergen in the household can apparently influence the likelihood of emergency admission of mite sensitive asthmatic children [6] and also increases the risk of readmission [7].…”

Asthma and altitude

“…Natural increase in mite allergen in houses has been related to the emergency admission of mite-sensitive asthmatic children, while similarly sensitive asthmatic controls whose house dust mite exposure was not increased do not relapse [19]. In addition, the presence and severity of the skin-prick test reaction to mites may be related to the subsequent asthma severity [20].…”