Cross-Cultural Adaptation, Reliability and Validity Study of the Persian Version of the Clinical COPD Questionnaire.

The clinical COPD questionnaire (CCQ) has been developed to measure the health status of COPD patients. The aim of this study was to translate CCQ into the Persian language and assess the validity and reliability of the translated version. We used a forward-backward procedure to translate the questionnaire. In a cross-sectional study 100 COPD patients and 50 healthy subjects over 40 years old were selected to assess the reliability and construct validity of the instrument. The face and content validity were used for the questionnaire validity. Validity was examined in a population of patients with COPD, using the Persian validated version of the St George's Respiratory Questionnaire (PSGRQ). In order to assess the questionnaire's reliability, the Intraclass correlation coefficient (ICC) and Cronbach's alpha were calculated. Test-retest reliability was tested by re-administering the Persian version of the CCQ (PCCQ) after 1 week. Test-retest carry out of data demonstrates that the PCCQ has excellent reliability (ICC for all 3 domains were higher than 0.9). Internal consistency was found by Cronbach's alpha to be 0.96, 0.94, 0.97, and 0.98 for the symptom, mental state, functional state and total scores respectively. In addition, the correlation between the components of PCCQ and PSGRQ showed satisfactory construct validity. Analyzing the data from healthy subjects and patients divulged that the PCCQ has acceptable discriminant validity. In general, the PCCQ had satisfactory reliability and validity for assessing health-related quality of life status of Iranian COPD patients.