Smoking cessation can improve quality of life among COPD patients: Validation of the clinical COPD questionnaire into Greek

BACKGROUND Chronic obstructive pulmonary disease (COPD) remains a major public health problem that affects the quality of life of patients, however smoking cessation may emeliorate the functional effects of COPD and alter patient quality of life. OBJECTIVE-DESIGN: The aim of this study was to validate the Clinical COPD Questionnaire (CCQ) into Greek and with such to evaluate the quality of life in patients with different stages of COPD, as also assess their quality of life before and after smoking cessation. RESULTS The internal validity of questionnaire was high (Cronbach's a = 0.92). The reliability of equivalent types in 16 stabilized patients also was high (ICC = 0.99). In general the domains within the CCQ were strongly correlated with each other, while each domain in separate was strongly correlated with the overall CCQ score (r2 = 0.953, r2 = 0.915 and r2 = 0.842 in regards to the functional, symptomatic and mental domain, respectively). The CCQ scores were also correlated with FEV1, (r2 = -0.252, p < 0.001), FEV1/FVC, (r2 = -0.135, p < 0.001) as also with the quality of life questionnaire SF-12 (r2 = -0.384, p < 0.001). Smoking cessation also lead to a significant reduction in CCQ score and increase in the SF-12 score. CONCLUSIONS The self administered CCQ indicates satisfactory validity, reliability and responsiveness and may be used in clinical practice to assess patient quality of life. Moreover the CCQ indicated the health related quality of life gains attributable to smoking cessation among COPD patients, projecting smoking cessation as a key target in COPD patient management.