Development and validity of the Patient-centred COPD Questionnaire (PCQ)

COPD-guidelines recommend regular evaluation of both the degree of airway obstruction and health-status to provide adequate treatment. Numerous health-status questionnaires have been developed of which the 'Clinical-COPD-Questionnaire' and the 'COPD-Assessment-Test' are best known; although highly recommended, both have several limitations regarding structure, content, and/or methodological qualities. In the present study a new COPD-specific instrument was developed to measure impairment: the 'Patient-centred-COPD-Questionnaire' (PCQ).

Six focus groups with COPD patients and (lung) health care providers from primary, secondary and tertiary (rehabilitation) care were formed to discuss aspects of COPD most relevant to patients' daily lives. Eighty candidate items were derived for explorative factor analyses (EFA) to test their psychometric properties (study I, n=541). These resulted in an 18-item scale that was further explored by confirmatory factor analyses (CFA) and construct and concurrent validity assessment (study II, n=412).

EFA in study I suggested a reliable three component solution ('shortness of breath', 'acceptance of COPD' and 'confidence in care'). In study II this model was confirmed with CFA, and significant and clinically relevant correlations were found between the PCQ subscales, and other COPD specific and general health questionnaires. Furthermore, multivariate analyses of covariance revealed that more severely ill patients reported more impairment.

The PCQ is a questionnaire with three dimensions to assess the impact of COPD on daily life that is easy to complete. For the first time, a dimension referring to 'confidence in care' is included in a tool that assesses COPD-related impairment.