Aims: To develop a model of prognosis for time receiving workers' compensation wage replacement benefits in the first year.
Methods: A prospective cohort of 907 injured workers off work because of soft tissue injuries was followed for one year through structured telephone interviews and administrative data sources. Workers were recruited at workers' compensation claim registration. Only those still off work at four weeks post-registration were included in the analysis. Data from several domains (demographics, clinical factors, workplace factors, recovery expectations) were collected at approximately two weeks and a subset again at four weeks. Outcome was duration on total temporary wage replacement benefits. Variable selection was carried out in two steps using content experts and backward elimination with the Cox model.
Results: Body region specific functional status, change in pain, workplace offers of arrangements for return to work, and recovery expectations were independently predictive of time on benefits. Change in pain and workplace offers interacted, so the largest mutual association occurred for those whose pain was getting worse—that is, reduction in median duration from 112.5 to 32.5 days. Across observed values, widely different recovery profiles of groups of workers resulted; for example, at four months, only one third of the highest risk group had gone off benefits while over 95% of the lowest risk group had done so.
Conclusions: Focus on a relatively small set of prognostic factors should enable occupational health practitioners to triage injured workers within the first month and concentrate on those requiring additional assistance to return to work.