Maximal Airway Response in Adolescents With Long-term Asthma Remission and Persisting Airway Hypersensitivity: Inhaler
In the second phase of study, only the subjects who demonstrated a maximal response plateau were studied. The subjects with asthma remission were randomly allocated into two treatment groups to receive either budesonide (two 200-^g puffs bid; total dosage, 800 ^g/d: budesonide/remission group) or placebo (two 500-^g puffs bid of micronized lactose: placebo/remission group), inhaled using a dry-powder inhaler (Turbuhaler; Astra Draco; Sodertalje, Sweden). The randomization, allocation, and blinding procedures used the Consolidated Standards of Reporting Trials statement as a guide. Medications were supplied in identical devices so that patients and doctors remained unaware of a particular subject’s treatment allocation. Subjects with current asthma received inhaled budesonide at the same dosage as the budesonide/remission group (budesonide/symptomatic group). These three groups followed their assigned course of medications for 6 months, with follow-up visits, including spirometry and a methacholine challenge test, every 3 months. Subjects in the budesonide/symptomatic group were allowed to use inhaled p2-agonist on an as-needed basis to control their possible symptoms during the course of the study. Theophylline, which may reduce BHR, was not allowed. Subjects attended the laboratory at the same time of day on each visit, having refrained from all medications for 8 h and caffeine-containing beverages for 4 h prior. Measurements were taken only during clinically stable periods, and not within 4 weeks of viral respiratory illness. For respiratory tract infection with purulent sputum, antibiotics were administered. The dry-powder inhalation technique was checked before the start of the study and at every visit. Subjects were advised to rinse their mouth and throat after drug inhalation. Patient compliance with the recommended use of budesonide was checked by self-reported doses in diaries and by examining a red mark in the indicator window of the returned dry-powder inhaler.