Direct and mediated effects of treatment context on low back pain outcome: a prospective cohort study

OBJECTIVES: Contextual components of treatment previously associated with patient outcomes include the environment, therapeutic relationship and expectancies. Questions remain about which components are most important, how they influence outcomes and comparative effects across treatment approaches. We aimed to identify significant and strong contextual predictors of patient outcomes, test for psychological mediators and compare effects across three treatment approaches. DESIGN: Prospective cohort study with patient-reported and practitioner-reported questionnaire data (online or paper) collected at first consultation, 2 weeks and 3 months. SETTING: Physiotherapy, osteopathy and acupuncture clinics throughout the UK. PARTICIPANTS: 166 practitioners (65 physiotherapists, 46 osteopaths, 55 acupuncturists) were recruited via their professional organisations. Practitioners recruited 960 adult patients seeking treatment for low back pain (LBP). PRIMARY AND SECONDARY OUTCOMES: The primary outcome was back-related disability. Secondary outcomes were pain and well-being. Contextual components measured were: therapeutic alliance; patient satisfaction with appointment systems, access, facilities; patients’ treatment beliefs including outcome expectancies; practitioners’ attitudes to LBP and practitioners’ patient-specific outcome expectancies. The hypothesised mediators measured were: patient self-efficacy for pain management; patient perceptions of LBP and psychosocial distress. RESULTS: After controlling for baseline and potential confounders, statistically significant predictors of reduced back-related disability were: all three dimensions of stronger therapeutic alliance (goal, task and bond); higher patient satisfaction with appointment systems; reduced patient-perceived treatment credibility and increased practitioner-rated outcome expectancies. Therapeutic alliance over task (η(p)(2)=0.10, 95% CI 0.07 to 0.14) and practitioner-rated outcome expectancies (η(p)(2)=0.08, 95% CI 0.05 to 0.11) demonstrated the largest effect sizes. Patients’ self-efficacy, LBP perceptions and psychosocial distress partially mediated these relationships. There were no interactions with treatment approach. CONCLUSIONS: Enhancing contextual components in musculoskeletal healthcare could improve patient outcomes. Interventions should focus on helping practitioners and patients forge effective therapeutic alliances with strong affective bonds and agreement on treatment goals and how to achieve them.