The Relationship between the Severity of Airway Obstruction and COPD Diagnostic Questionnaire Score in COPD Patients

Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airflow limitation and systemic inflammation which is also associated with pulmonary and extra-pulmonary complications. COPD Diagnostic Questionnaire (CDQ) is a valid questionnaire that is used to identify patients with COPD. The purpose of this study was to determine the relationship between the severity of airflow limitation and the CDQ score in COPD patients. In this study, 100 patients with COPD and smoking history were included. The diagnosis of COPD was established based on American Thoracic Society (ATS) guidelines: cough and expulsion of phlegm, chronic dyspnea, obstructive spirometric pattern (forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) <70%). Disease severity was classified according to GOLD criteria. After obtaining consent, demographic data, history of smoking, the exacerbation rate in the past year, arterial oxygen saturation (Spo2) and spirometer variables were recorded. Then, CDQ and Modified Medical Research Council (MMRC) dyspnea score were completed. Also, the associations of the CDQ score with FEV1% predicted and clinical parameters of patients were tested. All studied patients were male. There was a significant relationship between CDQ score with FEV1% (p<0.001), GOLD stage (p<0.01), Spo2 (p<0.01), exacerbation rate (p<0.01) and severity of dyspnea according to MMRC dyspnea scale (p<0.01). The CDQ can be used to determine airflow limitation, severity of dyspnea and exacerbation rate in COPD patients. Therefore, it is recommended that this questionnaire can be used in primary health centers for identifying and referring of COPD patients.