Physiotherapy informed by Acceptance and Commitment Therapy (PACT): protocol for a randomised controlled trial of PACT versus usual physiotherapy care for adults with chronic low back pain

INTRODUCTION: Chronic low back pain (CLBP) is a common condition and source of significant suffering, disability and healthcare costs. Current physiotherapy treatment is moderately effective. Combining theory-based psychological methods with physiotherapy could improve outcomes for people with CLBP. The primary aim of this randomised controlled trial (RCT) is to evaluate the efficacy of Physiotherapy informed by Acceptance and Commitment Therapy (PACT) on functioning in patients with CLBP. METHODS AND ANALYSIS: The PACT trial is a two-armed, parallel-group, multicentre RCT to assess the efficacy of PACT in comparison with usual physiotherapy care (UC). 240 patients referred to physiotherapy with CLBP will be recruited from three National Health Service (NHS) hospitals trusts. Inclusion criteria are: age ≥18 years, CLBP ≥12-week duration, scoring ≥3 points on the Roland-Morris Disability Questionnaire (RMDQ) and adequate understanding of spoken and written English to participate. Patients will be randomised to PACT or UC (120 per arm stratified by centre) by an independent randomisation service and followed up at 3 and 12 months post randomisation. The sample size of 240 will provide adequate power to detect a standardised mean difference of 0.40 in the primary outcome (RMDQ; 5% significance, 80% power) assuming attrition of 20%. Analysis will be by intention to treat conducted by the trial statistician, blind to treatment group, following a prespecified analysis plan. Estimates of treatment effect at the follow-up assessments will use an intention-to-treat framework, implemented using a linear mixed-effects model. ETHICS AND DISSEMINATION: This trial has full ethical approval (14/SC/0277). It will be disseminated via peer-reviewed publications and conference presentations. The results will enable clinicians, patients and health service managers to make informed decisions regarding the efficacy of PACT for patients with CLBP. TRIAL REGISTRATION NUMBER: ISRCTN95392287; Pre-results.