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 Rehabilitation

• Certain 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.

Keywords::

• Musculoskeletal disorder
• psychometrics
• Revised Illness Perception Questionnaire adapted for Work Disability (IPQR-WD)
• representation
• work

Acknowledgments

This study was made possible through the commitment of clinicians and workers who participated in the project. Authors also wish to thank Djamal Berbiche, senior biostatistician, for his contributions to the statistical analyses.

Declaration of Interest: VA received funding for her master’s studies from the Institut de recherche Robert-Sauvé en santé et sécurité du travail (IRSST) and from the Ordre des Ergothérapeutes du Québec (OEQ). MFC and MJD received salary awards from the Fonds de Recherche en Santé du Québec (FRSQ).