Measurement properties of a new quality of life measure for patients with work disability associated with musculoskeletal pain.

ABSTRACT

INTRODUCTION: The Quality of Life Systemic Inventory (QLSI) measures patients' goal attainment based on the system control theory. It quantifies the perceived impact of the disorder and the gap between the present and aspired states. PURPOSE: To evaluate concurrent validity and responsiveness of the QLSI among workers on sick leave due to musculoskeletal disorders (MSDs). METHODS: Participants (10 women; 29 men) were recruited at a work rehabilitation centre and had more than 4 weeks of absence from work due to MSDs compensated by the Workers' Compensation Board. Concurrent validity and external responsiveness were based on baseline and post-treatment measures of external criteria. Criteria and related instruments were the following perception of disability (Roland-Morris Disability Questionnaire); health-related quality of life (SF-12); stress (Psychological Stress Measure) and distress (Psychological Distress Index). RESULTS: Regression analyses revealed significant correlations between QLSI scores and the Psychological Distress Index (r2 = .11 to .19 and .66; p < .001), with either the SF-12 mental component scale (r2 = .18 and .11; p < .01) or the Roland-Morris Disability Questionnaire (r2 = .04 and .10; p < .05). All measures showed highly significant change over time. CONCLUSION: Results support the concurrent validity and responsiveness of the QLSI, with an MSD population. SIGNIFICANCE: This instrument could serve in future research as an outcome measurement instrument in the evaluation of more long-term effects of rehabilitation programs.