Internal consistency and construct validity of the Revised Illness Perception Questionnaire adapted for work disability following a musculoskeletal disorder.

Abstract

To assess internal consistency and construct validity of the French version of the Revised Illness Perception Questionnaire adapted for Work Disability (IPQR-WD). A cross sectional study was conducted in rehabilitation centers and private clinics in the Montreal region of Canada, involving 43 men and women, French speaking, absent from work between 3 months and a year due to musculoskeletal disorders. The 9 dimension IPQR-WD and the following eight-related instruments for construct validity were administered: Tampa Scale for Kinesiophobia (TSK), Pain Catastrophizing Scale (PCS), Psychological Distress Index (PDI-14), Pain Disability Index (PDI), Self-Efficacy for Return to Work Scale (SERWS), Pain Beliefs and Perceptions Inventory (PBPI), Implicit Models of Illness Questionnaire (IMIQ) and a Visual Analog Scale for pain intensity (VAS). Calculations of Cronbach's α (from 0.58 to 0.87) revealed satisfactory internal consistency of the IPQR-WD dimensions. Multiple regression analyses were performed with each IPQR-WD dimension and significant independent variables. Final models explained a good proportion of the variance (adjusted r(2) = 0.33-0.70) for each dimension, except for the Cyclical timeline dimension for which associations became non-significant after adjusting for gender, age and length of sick leave. The SERWS and the VAS were not significantly associated to any of the IPQR-WD dimensions. Moderate to strong correlations were found with six-related instruments which support the multidimensional nature of the IPQR-WD and its unique contribution as one simple questionnaire that can assess representations related to work disability. [Box: see text].