Outcomes in distressed patients with chronic low back pain: Subgroup analysis of a clinical trial

STUDY DESIGN: Subgroup analysis of a controlled clinical trial. BACKGROUND: Current evidence suggests that people with chronic low back pain who are distressed may require different interventions than do those who are not distressed. Recently, the enhanced transtheoretical model intervention (ETMI) reported significant improvements in disability and pain and increased physical activity in patients with chronic low back pain compared to physical therapy as usual. OBJECTIVES: To compare outcomes between ETMI and physical therapy interventions for participants with and without self-reported distress. METHODS: We tested the interaction between intervention (ETMI versus physical therapy) and distress status (using the Medical Outcomes Study 12-Item Short-Form Health Survey cut point), and performed between-group comparisons on 3 separate outcomes (disability, pain, and physical activity) at 3 and 12 months. RESULTS: In the ETMI group, 57 of 108 participants were considered distressed, versus 62 of 106 participants in the physical therapy group. The interaction between intervention and distress at 12 months was significant. Participants improved with both interventions, but the magnitude of change in distressed participants who received ETMI was larger than that in distressed participants who received physical therapy (mean ± SD difference from baseline in disability of 6.1 ± 6.1 in the ETMI group, compared with 3.4 ± 6.7 in the physical therapy group). CONCLUSION: The enhanced transtheoretical model intervention was significantly more effective than physical therapy in participants with distress.