Validity of Questionnaire-Based Diagnosis of Chronic Obstructive Pulmonary Disease in Azar-Cohort Population

BACKGROUND The clinical diagnosis of chronic obstructive pulmonary disease (COPD) should be considered in any patient who has dyspnea, chronic cough or sputum production, and diagnosis should be confirmed by performing spirometry in presence of airflow limitation. The aim of this study was to assess the validity of a questionnaire used to detect COPD based on spirometry findings. MATERIALS AND METHODS The validity of a questionnaire for COPD diagnosis was examined using spirometry based on both Global Initiative for Chronic Obstructive Lung Disease (GOLD) and American Thoracic Society/European Respiratory Society (ATS/ERS) criteria for patients 35 years old and older. In total, 350 questionnaires were completed. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio and negative likelihood ratio were calculated to determine the accuracy of the questionnaire. RESULTS The sensitivity of the questionnaire in detection of airflow limitation was 8.3% and 6.7% by the GOLD and the ATS/ERS criteria, respectively; whereas, specificity was 96% by both criteria. CONCLUSION The high specificity of the questionnaire indicates that the questionnaire is more capable to identify people who do not have airflow limitation; whereas, the low sensitivity of the questionnaire could underestimate the actual prevalence of COPD in the general population.