Predictive validity of initial fear avoidance beliefs in patients with low back pain receiving physical therapy: is the FABQ a useful screening tool for identifying patients at risk for a poor recovery?

Abstract

Several prospective studies examining patients receiving physical therapy support the predictive validity of FABQ subscale scores. This has lead to the proposition that the FABQ would be a useful screening tool, permitting early identification of patients at risk for a poor outcome with an opportunity to modify the treatment accordingly. However, the predictive validity of the FABQ within physical therapy practice has yet to be examined. Predictive validity was analyzed between the FABQ-PA, FABQ-W using both disability and pain as the dependent variables using Pearson correlation coefficients and stepwise hierarchical linear regression modeling controlling for baseline variables. Separate analyses were run for patients with private health insurance and those receiving workers' compensation. Further analysis of predictive validity was performed by dichotomizing the outcome of physical therapy. Patients were coded as having a poor outcome if they failed to achieve a minimum clinically important change in disability over the course of treatment. The accuracy of previously reported cut-off scales for both the FABQ-W and FABQ-PA were examined for both payor types. Results of the hierarchical linear regression analyses for patients with private insurance showed neither the FABQ-PA nor the FABQ-W score significantly improved the explained variance in change in pain or disability. For patients receiving workers' compensation, only the FABQ-W subscale score significantly contributed to the model after controlling for the other baseline variables for both changes in disability and pain. Only the FABQ-W subscale was predictive of poor outcome and this was only identified in the worker's compensation group. The results suggest that the work subscale of the FABQ might be an appropriate screening tool to identify patients with work-related LBP who are at risk for a poor outcome with routine physical therapy. Neither FABQ subscale was predictive of outcome for patients with private insurance, and the use of the FABQ, as a screening tool for patients with non-work-related LBP was not supported.

Fig. 1

Flow diagram representing the identification of eligible patients