Possible cut-off values for stable or instable COPD as measured by the clinical COPD questionnaire (CCQ)

Background: Based on GINA the cut-off values for the Asthma Control Questionnaire (ACQ) have been established for “well-controlled” and “not well-controlled” asthma. Cut-off values for health status questionnaires like the Clinical COPD Questionnaire (CCQ) for use in COPD, however, are lacking. Objective: To give insight into possible cut-off values of the CCQ by comparing it with the ACQ. Method: In 7599 patients with respiratory disease, referred by the general practitioner to a diagnostic center, data on both the ACQ and CCQ were collected. Scores on both questionnaires were compared and possible cut-off values for the CCQ were determined by using the ACQ as gold standard. Results: After consultation with the diagnostic center, a diagnosis of COPD, asthma or a asthma/COPD was established in respectively 16,8%, 46,3% and 7,4% of the patients. The correlation between the ACQ and CCQ was 0.81. The mean ACQ and CCQ scores in these patients according to the level of control are presented in table 1. Discussion: The average CCQ per ACQ-score has been calculated and using the ACQ as gold standard this study estimated the cut-off points for the CCQ to be 1.7 for COPD with instable or uncontrolled disease.