Study design: Workers' compensation back injury claimants completed baseline and follow-up telephone interviews in a prospective population-based cohort study.
Objective: To compare the Roland-Morris Disability Questionnaire (RDQ) to widely used generic health status measures in a sample of workers with recent work-related back injuries in terms of validity, reliability, responsiveness to change, and floor and ceiling effects.
Summary of background data: Little research has directly compared the validity and responsiveness of the RDQ to that of the Short-Form 12 or Short-Form 36 health status measures among individuals with back pain. Furthermore, there is little information concerning the validity, reliability, and responsiveness of the RDQ as a measure of functional outcomes for workers with back injuries.
Methods: Approximately 8 weeks (median) after filing low back injury claims, 309 workers completed the RDQ, Short-Form 12, and Short-Form 36 scales and gave information about their work status in computer-assisted telephone interviews. An average of 5 months later, 284 workers (91.9%) completed the measures again.
Results: The RDQ demonstrated excellent internal consistency and validity through correlations with other measures of physical functioning, ability to discriminate between those working and those not working, and much more responsiveness to change than the Short-Form 12 and Short-Form 36 scales. However, 15% of the sample did not answer one or more RDQ items.
Conclusions: The RDQ is a valid measure of physical disability among workers with back injuries. Its greater responsiveness to change suggests its superiority to the Short-Form 12 and Short-Form 36 as an outcome measure in this population.