Are Pain-Related Fears Mediators for Reducing Disability and Pain in Patients with Complex Regional Pain Syndrome Type 1? An Explorative Analysis on Pain Exposure Physical Therapy

OBJECTIVE: To investigate whether pain-related fears are mediators for reducing disability and pain in patients with Complex Regional Pain Syndrome type 1 when treating with Pain Exposure Physical Therapy. DESIGN: An explorative secondary analysis of a randomised controlled trial. PARTICIPANTS: Fifty-six patients with Complex Regional Pain Syndrome type 1. INTERVENTIONS: The experimental group received Pain Exposure Physical Therapy in a maximum of five treatment sessions; the control group received conventional treatment following the Dutch multidisciplinary guideline. OUTCOME MEASURES: Levels of disability, pain, and pain-related fears (fear-avoidance beliefs, pain catastrophizing, and kinesiophobia) were measured at baseline and after 3, 6, and 9 months follow-up. RESULTS: The experimental group had a significantly larger decrease in disability of 7.77 points (95% CI 1.09 to 14.45) and in pain of 1.83 points (95% CI 0.44 to 3.23) over nine months than the control group. The potential mediators pain-related fears decreased significantly in both groups, but there were no significant differences between groups, which indicated that there was no mediation. CONCLUSION: The reduction of pain-related fears was comparable in both groups. We found no indication that pain-related fears mediate the larger reduction of disability and pain in patients with Complex Regional Pain Syndrome type 1 treated with Pain Exposure Physical Therapy compared to conventional treatment. TRIAL REGISTRATION: International Clinical Trials Registry NCT00817128