Spinal Manipulation and Clinician-Supported Self-Management for Preventing Chronic Low Back Pain Impact The PACBACK Randomized Clinical Trial

IMPORTANCE Acute and subacute low back pain (LBP) often progresses to a chronic impactful back problem in patients with elevated risk. The most effective way to prevent this progression is unknown. OBJECTIVE To determine the effectiveness of spinal manipulation and clinician-supported biopsychosocial self-management vs medical care for preventing chronic impactful LBP. DESIGN, SETTING, AND PARTICIPANTS This 2 × 2 factorial randomized clinical trial was conducted in research clinics at the University of Minnesota and the University of Pittsburgh, Pennsylvania, from November 2018 to May 2023, with follow-up concluding in June 2024. Adults with acute or subacute LBP with a moderate to high risk of chronicity were included. INTERVENTIONS Four interventions were applied for 8 weeks: spinal manipulation therapy; supported self-management; combined spinal manipulation therapy and supported self-management; and guideline-based medical care. Spinal manipulation and supported self-management were provided by physical therapists and chiropractors. MAIN OUTCOMES AND MEASURES Mean LBP impact score per the US National Institutes of Health Task Force on Chronic LBP scale (8 [best] to 50 [worst]) during 10 to 12 months, responder analyses of group differences in the proportion of participants with at least 50% reductions. A reduction of 30% was considered the minimal clinically important within-patient difference. Secondary outcomes included measures of chronicity and LBP burden (ie, health care and medication use, productivity), important patient-reported outcomes (eg, improvement, satisfaction), biopsychosocial measures (eg, Patient-Reported Outcomes Measurement Information System), and potential mediating psychosocial measures (eg, self-efficacy, kinesiophobia, pain catastrophizing). RESULTS Of the 1000 participants (mean [SD] age, 47 [16] years; 577 females [58%]) randomized, 928 (93%) completed the trial. An omnibus test of the primary outcome was statistically significant (P = .006). Group differences in mean LBP impact scores were small but statistically significant: supported self-management vs medical care, −1.7 (95% CI, −2.7 to −0.6); combined self-management and spinal manipulation vs medical care, −1.3 (95% CI, −2.5 to 0). Spinal manipulation therapy and medical care did not differ: −0.3 (95% CI, −1.5 to 1.0). Adding spinal manipulation to supported self-management did not provide additional benefit. The supported self-management group had a significantly higher proportion with at least 50% reduction in LBP impact vs medical care (64% vs 55%). Supported self-management also performed better on most secondary outcomes compared to medical care, including 12% fewer reporting chronic pain that frequently interfered with regular activities. Mediation analyses showed changes in psychosocial factors at 6 months and explained 76% of supported self-management effects at 1 year. CONCLUSIONS AND RELEVANCE This randomized clinical trial found that for patients with acute or subacute LBP at increased risk of chronic impactful LBP, clinician-supported biopsychosocial self-management resulted in a lower mean LBP impact score at 10 to 12 months vs medical care; spinal manipulation and medical care did not differ. While the LBP impact difference was small, the consistent results of the responder analyses and most secondary outcomes suggest differences between clinician-supported self-management and medical care are clinically relevant.