Abstract
Objective
The Fear-Avoidance Model of chronic pain (FAM) posits that pain catastrophizing and fear-avoidance beliefs are prognostic for disability and chronicity. In acute low-back pain, early physical therapy (PT) is effective in reducing disability in some patients. How early PT impacts short- and long-term changes in disability for patients with acute pain is unknown. Based on the FAM, we hypothesized that early reductions in pain catastrophizing and fear-avoidance beliefs would mediate early PT’s effect on changes in disability (primary outcome) and pain intensity (secondary outcome) over 3 months and 1 year.
Subjects
Participants were 204 patients with low-back pain of < 16 days duration, who enrolled in a clinical trial (NCT01726803) comparing early PT sessions or usual care provided over 4 weeks.
Methods
Patients completed the Pain Catastrophizing Scale (PCS), Fear-Avoidance Beliefs Questionnaire (FABQ work and physical activity scales) and outcomes (Oswestry Disability Index and Numeric Pain Rating Scale) at baseline, 4 weeks, 3 months, and 1 year. We applied longitudinal mediation analysis with single and multiple mediators.
Results
Early PT led to improvements in disability and pain over 3 months, but not 1 year. In the single mediator model, four-week reductions in pain catastrophizing mediated early PT’s effects on 3-month disability and pain intensity improvements, explaining 16% and 22% of the association, respectively, but the effects were small. Pain catastrophizing and fear-avoidance beliefs did not jointly mediate these associations.
Conclusions
In acute low-back pain, early PT may improve disability and pain outcomes at least partly through reducing patients’ catastrophizing.
Should treatment of (sub)acute low back pain be aimed at psychosocial prognostic factors? Cluster randomised clinical trial in general practice