Predictors of Long-Term Disability among Workers with Musculoskeletal Disorders

Investigators: Gary Franklin, Judy Turner, Deborah Fulton-Kehoe, Tom Wickizer, Kathleen Egan and Rae WU

Disability associated with work-related musculoskeletal disorders is an increasingly serious societal problem. Although most injured workers return quickly to work, a substantial number do not. The costs of chronic disability to the injured worker, his or her family, employers, and society are enormous. A means of accurate early identification of injured workers at risk for chronic disability could enable these individuals to be targeted for early intervention to promote return to work and normal functioning. The purpose of this study was to develop statistical models that accurately predict chronic work disability from data obtained from administrative databases and worker interviews soon after a work injury. Based on these models, we developed a brief instrument that could be administered in medical or workers' compensation settings to screen injured workers for chronic disability risk soon after injury.

This is a population-based, prospective study. The study population consisted of workers who filed claims for work-related back injuries or carpal tunnel syndrome (CTS) in Washington State. The Washington State Department of Labor and Industries claims database was reviewed weekly to identify workers with new claims for work-related back injuries and CTS, and these workers were telephoned and invited to participate. Workers who enrolled completed a computer-assisted telephone interview at baseline and one year later. The baseline interview assessed sociodemographic, employment-related, biomedical/health care, legal, and psychosocial risk factors. The follow-up interview assessed pain, disability, and work status. The primary outcome was duration of work disability over the year after claim submission, as assessed by administrative data. Secondary outcomes included work disability status at one year, as assessed by both self-report and work disability compensation status (administrative records).

We published a manuscript (Publication 2 below) that reports the results of analyses examining: (1) the optimal cutpoints of worker ratings of their pain intensity (0-10 numerical rating scale) for discriminating various levels of disability among workers with CTS and low back (LB) injuries, (2) whether these cutpoints differ for these two conditions and for different disability measures, and (3) whether the relationship between pain intensity and disability is linear or nonlinear in each injury group.

We have also reported on the ability of our measures of worker pain, disability, and psychosocial characteristics to predict work disability among those with low back injuries. At 6 months, 18% of the workers in our sample were receiving work disability compensation. Age, race, education, and baseline pain and disability were significant predictors of 6-month disability. Adjusting for baseline demographics, pain, disability, and other psychosocial variables, high work fear-avoidance and very low work recovery expectations were significant independent predictors of long term disability.

The brief screening instrument developed by this study is described here.

  1. Turner, J.A., Franklin, G., Fulton-Kehoe, D., Egan, K., Wickizer, T.M., Lymp, J.F., Sheppard, L., Kaufman, J.D.: Prediction of chronic disability in work-related musculoskeletal disorders:   a prospective, population-based study.   BMC Musculoskeletal Disorders, 5: 14 , 2004.
  2. Turner, J.A., Franklin, G., Heagerty, P.J., Wu, R., Egan, K., Fulton-Kehoe, D., Gluck, J.V., Wickizer, T.M.:   The association between pain and disability. Pain, 112: 307-314 , 2004.
  3. Turner, J.A., Franklin, G., Fulton-Kehoe, D., Sheppard, L., Wickizer, T.M., Wu, R., Gluck, J., Egan, K.:   Work recovery expectations and fear-avoidance predict work disability among individuals with workers' compensation back injuries:   a longitudinal, population-based study.   Spine, in press.