The association between physical intervention use and treatment outcomes in patients participating in an online and psychologically informed pain management program.

Background: The availability of multidisciplinary care for the management of chronic pain is uncommon outside specialist clinics. The present study aims to determine the physical intervention use of patients participating in an online psychological pain management program and whether exposure to physical interventions in these patients alters treatment outcomes compared with patients who do not access physical interventions.

Methods: Data were obtained from 2 previously published randomized controlled trials of an online psychological pain management program. Physical intervention exposure (categories: none, 1-3 sessions, 4+ sessions) was assessed at baseline, after treatment, and at 3-month follow-up. Primary outcomes included depression, anxiety, pain intensity, and pain-related disability. Generalized estimating equation models were used to compare treatment outcomes among those with different physical intervention frequencies and periods of exposure. We assessed whether changes in primary outcomes differed (moderated) by the period and category of physical intervention exposure.

Results: Of the patients (n = 1074) who completed the baseline questionnaire across both randomized controlled trials, 470 (44%) reported physical intervention use at baseline, 383 (38%) reported physical intervention use after treatment, and 363 (42%) reported physical intervention use at 3-month follow-up. On average, there were moderate-large reductions from baseline to after treatment with respect to all outcomes (Cohen's d = 0.36-0.82). For all outcomes, the interaction of time by physical intervention exposure was statistically nonsignificant.

Conclusion: A substantial proportion of patients who participated in a psychologically informed pain management program were establishing, continuing, or stopping additional physical interventions. The frequency of and period of exposure to physical interventions did not appear to moderate treatment outcomes.

Clinical Trial Registration: Australian and New Zealand Clinical Trials Registry (ACTRN12613000252718 and ACTRN12615001003561). The website for registration information is https://www.anzctr.org.au.