title: The response to bronchodilators in adults is not predictive of bronchial-hyperreactivity.
abstract: BACKGROUND
  In some subjects with suspected asthma who have normal spirometry, administration of bronchodilators (BD) improves expiratory flow rates. The predictive value of this phenomenon in adults is not known.
  
  
  OBJECTIVE
  To evaluate the predictive value of the response to BD for bronchial hyper-responsiveness (BHR) using the metacholine challenge test (MCT). Patients and methods. The study population included 62 non-smoking adult patients (41.9% women) 29.5 +/- 15.5 years of age (range 18-64 years) with suspected asthma with normal spirometry that underwent MCT within 1 week. The response to BD (200 mu g inhaled salbutamol) was compared between subjects with positive and negative MCT using cutoff levels of provocative concentrations of metacholine causing a 20% decrease in forced expiratory volume in 1 second (FEV(1)) (PC(20)) of 4 and 8 mg/mL.
  
  
  RESULTS
  Mean (+/- SD) baseline FEV(1) was 87.8 +/- 12% of predicted. After BD administration the mean FEV(1) increased by 4.3 +/- 3.9%. The prevalence of BHR was 17.7% and 25.8% for PC(20) for PC(20) of 4 mg/mL and 8 mg/mL, respectively. The post-BD FEV(1) increment for subjects with positive and negative MCT tests was 3.9% +/- 3.3% versus 4.4% +/- 4.1%, respectively; p = 0.89, using cutoff of 4 mg/mL. The corresponding figures for cutoff of 8 mg/ml were 4.3% +/- 3.1% vs. 4.3% +/- 4.2%, respectively; p = 0.8465. There was no correlation between post-BD FEV(1) increment and PC(20) values in patients with positive MCT test for the above-mentioned cutoff levels (correlation coefficient r = 0.1645, p = 0.6289; and r = 0.2417, p = 0.4051, respectively).
  
  
  CONCLUSIONS
  In adults with suspected asthma who have normal spirometry, the response to BD cannot be used to predict BHR.
authors: Division of Pulmonary Medicine, Rambam Health Care Campus, Technion, Institute of Technology, Haifa, Israel.
authors: Oren
authors: O
authors: Fruchter
authors: Emilia
authors: E
authors: Hardak
authors: Mordechai
authors: M
authors: Yigla
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000420:Albuterol / Q000627:therapeutic use*; D016535:Bronchial Hyperreactivity / Q000175:diagnosis / Q000188:drug therapy*; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D011237:Predictive Value of Tests; D012129:Respiratory Function Tests; D055815:Young Adult
chemical_list: D001993:Bronchodilator Agents; D016210:Methacholine Chloride; D000420:Albuterol