title: The feasibility of airways hyperresponsiveness as an inclusion criterion for studies on childhood asthma.
abstract: The feasibility of moderately severe airway hyperresponsiveness (AH) was examined as an inclusion criterion for clinical trials in asthmatic children. During the baseline period of a long-term clinical trial in asthmatic children, maintenance therapy with fluticasone (200 microg x day(-1)) was stopped for a maximum of 8 weeks and methacholine challenges were performed at 2-week intervals or earlier if the patients' condition deteriorated. Patients were eligible to continue the study if the provocative dose of methacholine causing a 20% fall in forced expired volume in one second (FEV1) (PD20) was <80 microg. Fifty-one per cent of the children did not develop a PD20 < 80 microg after withdrawal of fluticasone. Patients with or without a PD20 <80 microg did not differ in duration of asthma, duration of treatment, or peak flow variation. Patients with a PD20 <80 microg had higher levels of total and specific immunoglobulin-E, and lower levels of FEV1 and mean maximal expiratory flow than patients with a PD20 > or = 80 microg. Forty-four per cent of the patients with a PD20 > or = 80 microg did not have any symptoms during the wash-out period and 39% of these patients remained free from symptoms during one year follow-up. The results of this study suggest that recruiting asthmatic children for clinical trials may be difficult if airways hyperresponsiveness is used as the sole inclusion criterion.
authors.affiliation: Dept of Pediatrics, Isala Klinieken/Weezenlanden Hospital, Zwolle, The Netherlands.
authors.forename: A W
authors.initials: AW
authors.lastname: Kamps
authors.forename: M J
authors.initials: MJ
authors.lastname: Visser
authors.forename: T W
authors.initials: TW
authors.lastname: de Vries
authors.forename: W M
authors.initials: WM
authors.lastname: van Aalderen
authors.forename: D S
authors.initials: DS
authors.lastname: Postma
authors.forename: P L
authors.initials: PL
authors.lastname: Brand
mesh_terms: D000730:Androstadienes / Q000008:administration & dosage / Q000009:adverse effects; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy*; D016535:Bronchial Hyperreactivity / Q000175:diagnosis / Q000188:drug therapy*; D001985:Bronchial Provocation Tests; D002648:Child; D002986:Clinical Trials as Topic; D005240:Feasibility Studies; D005260:Female; D000068298:Fluticasone; D006801:Humans; D008134:Long-Term Care; D008297:Male; D016210:Methacholine Chloride; D018579:Patient Selection; D013375:Substance Withdrawal Syndrome / Q000175:diagnosis
chemical_list: D000730:Androstadienes; D016210:Methacholine Chloride; D000068298:Fluticasone