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

Abstract

Purpose: To assess internal consistency and construct validity of the French version of the Revised Illness Perception Questionnaire adapted for Work Disability (IPQR-WD). Method: 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). Results: 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 r2 = 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. Conclusions: 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.Implications for RehabilitationCertain unhelpful beliefs related to the worker’s own understanding (i.e. representation) of his/her current health condition may lead to behaviours that are poorly adapted to reducing the work disability following a musculoskeletal disorder.The Revised Illness Perception Questionnaire adapted for Work Disability (IPQR-WD) is the only questionnaire available in French that can specifically assess the worker’s representation following a musculoskeletal disorder.The use of this questionnaire will facilitate a systematic evaluation of the worker’s representation according to a biopsychosocial approach, which may contribute to a clinical practice based on the latest scientific evidences available in the work disability field.