Mind-Body Activity Program for Chronic Pain: Exploring Mechanisms of Improvement in Patient-Reported, Performance-Based and Ambulatory Physical Function

BACKGROUND: Improving physical function among patients with chronic pain is critical for reducing disability and healthcare costs. However, mechanisms underlying improvement in patient-reported, performance-based, and ambulatory physical function in chronic pain remain poorly understood. PURPOSE: To explore psychosocial mediators of improvement in patient-reported, performance-based, and objective/accelerometer-measured physical function among participants in a mind-body activity program. METHODS: Individuals with chronic pain were randomized to one of two identical 10-week mind-body activity interventions aimed at improving physical function with (GetActive-Fitbit; N=41) or without (GetActive; N=41) a Fitbit device. They completed self-reported (WHODAS 2.0), performance-based (6-minute walk test), and objective (accelerometer-measured step-count) measures of physical function, as well as measures of kinesiophobia (Tampa Kinesiophobia Scale), mindfulness (CAMS-R), and pain resilience (Pain Resilience Scale) before and after the intervention. We conducted secondary data analyses to test mediation via mixed-effects modeline. RESULTS: Improvements in patient-reported physical function were fully and uniquely mediated by kinesiophobia (Completely Standardized Indirect Effect (CSIE)=.18; CI=0.08, 0.30; medium-large effect size), mindfulness (CSIE=−.14; CI=−25, −.05; medium effect size) and pain resilience (CSIE=−.07; CI=−.16, −.005; small-medium effect size). Improvements in performance-based physical function were mediated only by kinesiophobia (CSIE=−.11; CI=−23, −.008; medium effect size). No measures mediated improvements in objective (accelerometer measured) physical function. CONCLUSION: Interventions aiming to improve patient-reported physical function in patients with chronic pain may benefit from skills that target kinesiophobia, mindfulness, and pain resilience, while those focused on improving performance-based physical function should target primarily kinesiophobia. More research is needed to understand mechanisms of improvement in objective, accelerometer-measured physical function. TRIAL REGISTRATION: ClinicalTrials.gov NCT03412916.