Validation of a risk factor-based intervention strategy model using data from the readiness for return to work cohort study.

Background: Low back pain (LBP) is a common and in some cases disabling condition. Until recently, workers presenting with non-specific LBP have generally been regarded as a homogeneous population. If this population is not homogeneous, different interventions might be appropriate for different subgroups. We hypothesized that (1) Clusters of individuals could be identified based on risk factors, (2) These clusters would predict duration and recurrences 6 months post-injury.

Methods: The study focuses on the 442 LBP claimants in the Readiness for Return-to-Work Cohort Study. Claimants (n = 259) who had already returned to work, approximately 1 month post-injury were categorized as the low risk group. A latent class analysis was performed on 183 workers absent from work, categorized as the high risk group. Groups were classified based on: pain, disability, fear avoidance beliefs, physical demands, people-oriented culture and disability management practice at the workplace, and depressive symptoms.

Results: Three classes were identified; (1) workers with 'workplace issues', (2) workers with a 'no workplace issues, but back pain', and (3) workers having 'multiple issues' (the most negative values on every scale, notably depressive symptoms). Classes 2 and 3 had a similar rate of return to work, both worse than the rate of class 1. Return-to-work status and recurrences at 6 months were similar in all 3 groups.

Conclusion: This study largely confirms that several subgroups could be identified based on previously defined risk factors as suggested by an earlier theoretical model by Shaw et al. (J Occup Rehab 16(4):591-605, 2006). Different groups of workers might be identified and might benefit from different interventions.