The response to bronchodilators in adults is not predictive of bronchial-hyperreactivity.
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.
Fruchter
Oren
O
Division of Pulmonary Medicine, Rambam Health Care Campus, Technion, Institute of Technology, Haifa, Israel.
Hardak
Emilia
E
Yigla
Mordechai
M
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
D001993:Bronchodilator Agents; D016210:Methacholine Chloride; D000420:Albuterol