Article

Many interventions for the treatment of low back pain exist, but the
mechanisms through which such treatments work are not always clear. This
situation is especially true for biopsychosocial interventions that incorporate
several different components and methods of delivery. Objective: The study
objective was to examine the indirect effects of the Cognitive Patient Education
(COPE) intervention via illness perceptions, back pain myths, and pain
catastrophizing on disability outcome.
This study was a secondary
analysis of the COPE randomized controlled trial. Methods: Mediation analysis
techniques were employed to examine the indirect effects of the COPE intervention
via residualized change (baseline - posttreatment) in the 3 variables
hypothesized to be targeted by the COPE intervention on posttreatment disability
outcome. Pain intensity at baseline, pain duration, clinician type, and a
treatment-mediator interaction term were controlled for in the analysis. Results:
Preliminary analyses confirmed that changes in pain catastrophizing and illness
perceptions (not back pain myths) were related to both allocation to the
intervention arm and posttreatment disability score. The treatment exerted
statistically significant indirect effects via changes in illness perceptions and
pain catastrophizing on posttreatment disability score (illness perceptions
standardized indirect effect = 0.09 [95% CI = 0.03 to 0.16]; pain catastrophizing
standardized indirect effect = 0.05 [95% CI = 0.01 to 0.12]). However, the
inclusion of an interaction term led to the indirect effects being significantly
reduced, with the effects no longer being statistically significant. Limitations:
This study presents a secondary analysis of variables not identified a priori as
being potentially important treatment targets; other, unmeasured factors could
also be important in explaining treatment effects. Conclusions: The finding that
small indirect effects of the COPE intervention via changes in illness
perceptions and pain catastrophizing on posttreatment disability could be
estimated indicates that these variables may be viable treatment targets for
biopsychosocial interventions; however, this finding must be viewed in light of
the adjusted analyses, which showed that the indirect effects were significantly
reduced through the inclusion of a treatment-mediator interaction term.

Langue : ANGLAIS