Psychometric properties of Chronic Pain Acceptance Questionnaires: a systematic review.

BACKGROUND Theoretically, acceptance of chronic pain (CP) is an important determinant in the functional status and well-being of patients with CP. Several questionnaires that aim to measure acceptance of CP have been developed. An overview of the psychometric properties of these questionnaires is unavailable. METHODS A systematic review of the literature of the psychometric properties of questionnaires that aim to measure acceptance of CP was performed. Psychometric properties including content construct and criterion validity, internal consistency. agreement, reliability, responsiveness, floor/ceiling effects and interpretability, were assessed using a standardized protocol. All studies were assessed by two observers independent from each other. RESULTS A total of 23 studies including 4 questionnaires or subscales were identified. The questionnaires/subscales included were the Chronic Pain Acceptance Questionnaire (CPAQ), Illness Cognitions Questionnaire (ICQ), Pain Solutions Questionnaire (PASOL) and Acceptance of Illness Scale (AIS) adapted to pain. When applying the criteria of the protocol, results indicate that none of the questionnaires are currently able to meet all 9 criteria for psychometric quality. Individual questionnaires met between 0 and 3 of the criteria. CONCLUSIONS If strict psychometric quality criteria are applied, none of the questionnaires are currently able to meet all nine criteria for psychometric quality, but overlooking the cumulative results over all the studies conducted, especially for the CPAQ, it can be concluded that information on several important characteristics has been reported and a fairly clear picture emerges about the psychometric properties of the CPAQ.