Differential predictors of the long-term levels of pain intensity, work disability, healthcare use, and medication use in a sample of workers' compensation claimants

The fear avoidance model of pain (FAM) conceptualizes pain catastrophizing as the cognitive antecedent of pain-related fear, and pain-related fear as the emotional antecedent of depression and disability. The FAM is essentially one of mediation whereby pain-related fear becomes the process by which depression or disability ensue. However, emerging literature suggests that pain catastrophizing, pain-related fear, and depression might be at least partially distinct in their prediction of different pain-related outcomes. The primary purpose of the present study was to evaluate whether psychological factors in the FAM (pain catastrophizing, pain-related fear, and depression) differentially predict long-term pain-related outcomes. Toward this objective, we conducted a prospective study using a cohort of 202 individuals with subacute work-related musculoskeletal injuries. Participants completed a 7-week physical therapy program with a functional rehabilitation orientation. Posttreatment measures of fear of movement, pain catastrophizing, depression, and pain self-efficacy were used to predict the persistence of pain symptoms, healthcare use, medication use, and return-to-work at one-year follow-up. Results from hierarchical linear and logistic regression analyses revealed that pain catastrophizing and fear of movement act as differential predictors of long-term pain-related outcomes. Specifically, we found unique relationships between pain catastrophizing and long-term pain intensity, and fear of movement and long-term work disability. After controlling for pain intensity and FAM variables, pain self-efficacy was shown to be a unique predictor of medication use. Implications for the FAM and the clinical management of musculoskeletal pain conditions are discussed.