Diagnostic values of bronchodilator response versus 9-question questionnaire for asthma

Introduction: Several studies have investigated different tools for asthma diagnosis in order to reduce the cost and improve its early recognition. The goal of this study is to establish a short questionnaire to be used in practice for asthma screening and compare diagnostic values between this method and spirometric response to bronchodilators. Material and method: 208 patients presenting with chronic stable dyspnea (> 6 months) and definite clinical diagnosis of chronic obstructive pulmonary disease, bronchiectasis, pulmonary fibrosis or asthma, were enrolled. 9 questions out of 43 based on the literature search were selected by regression analysis. Patients were asked to complete the questionnaire and then their spirometric responses to bronchodilators were evaluated. Results: Of all, 53.8% of cases were diagnosed clinically to have asthma. For establishing diagnosis of asthma, the bronchodilator test had 48.2% sensitivity, 78.1% specificity, 72% positive, 56.4% negative predictive values, 2.2 positive, 0.66 negative likeli-hood ratios, and false positive, false negative and accuracy of 21.9%, 51.8% and 62.01%, respectively. The revised 9 questions from the questionnaire had 97.3% sensitivity, 77.1% specificity, 83.2% positive, 96.1% negative predictive values, 4.24 positive, 0.03 negative likelihood ratios, 22.9% false positive, 2.7% false negative and 87.98% accuracy. Conclusions: The 9-question questionnaire had better diagnostic values in defining asthma in patients with chronic dyspnea than reversibility of airway obstruction to salbutamol and can be used as a useful screening test for diagnosis of asthma in clinical practice and for investigational purposes.