OBJECTIVE INDICATORS OF SEVERITY OF ASTHMA

Subjects with asthma who are intensively treated in residential care f acilities frequently demonstrate marked clinical improvement in their disease, with fewer attacks and improved well being. Despite their imp roved status it is known that pulmonary function test results often re main abnormal in patients with asthma. This prospective study on child ren with asthma receiving residential care was carried out to determin e which pulmonary function parameter best reflected clinical improveme nt through correlation with the duration of complete freedom from whee zing. Evaluated in 42 children were spirometry values including forced vital capacity forced expiratory volume in 1 second, peak expiratory pow rate, forced expiratory pow (between 25% and 75% of forced vital c apacity), and lung volumes as reflected by residual volume/total lung capacity. Bronchial hyperreactivity as reflected by bimonthly provocat ive concentration causing a 20% fall in FEV(1) in response to methacho line inhalation was evaluated in 18 patients. All pulmonary function t est results were correlated with days since last wheezing episode. Res ults indicate that only peak expiratory pow rate (r = 0.91; p < 0.001) , forced expiratory volume in 1 second (r = 0.69; p < 0.01), and force d expiratory flow (r = 0.62; p < 0.05) demonstrated significant correl ation with the number of days since last wheezing episode. Of particul ar interest was the failure of bronchial hyperreactivity to improve de spite intensive therapy with bronchodilators and corticosteroids. Pers istence of bronchial hyperreactivity despite intensive therapy with co rticosteroids suggests that in at least some children with severe asth ma, bronchial hyperreactivity may be especially long-lived may be perp etuated by inhaled beta(2) agonists, or may exist independently of air way inflammation.