Sustainability of cognitive behavioural interventions for chronic back pain: A long-term follow-up.

Background: There is a significant research gap with respect to the long-term sustainability of psychological treatment effects in chronic pain patients. This study aimed to investigate long-term treatment effects of two psychological treatments: cognitive behavioural therapy (CBT) as a broad-spectrum approach and exposure as a specific intervention for fear-avoidant pain patients.

Methods: Patients with chronic low back pain were randomized to CBT or exposure in vivo. Long-term follow-up (LTFU) data were available for 64 patients up to 8 years after treatment, with a response rate of 73%. The primary outcomes were pain-related disability and pain intensity and secondary outcomes were emotional distress, psychological flexibility, catastrophizing and pain-related fear. The data analysis was performed with longitudinal multilevel modelling.

Results: Multilevel analyses showed improvements in all primary outcomes as well as all secondary outcomes from pre-treatment to LTFU for both treatments. The mean proportion of cases meeting reliable and clinical improved criteria in all primary outcome was 36% (range: 22%-46%) in the exposure group and 50% (range: 33%-60%) in the CBT group. Dropout analyses revealed significantly higher deterioration rates over time. Pre-treatment to LTFU effect sizes of the primary outcomes ranged from 0.54 to 1.59.

Conclusions: Our results indicate that the effects of psychological treatments might be stable over several years. Treatment gains for exposure as a stand-alone treatment seem to be of shorter duration than a general CBT intervention. Thus, psychological treatments might offer a promising and sustainable long-term perspective for patients with chronic back pain.

Significance: The long-term stability of treatment effects is a highly neglected issue despite its inherent importance in the context of chronic pain. This study is the first to investigate treatment effects of cognitive behavioural therapy and in vivo exposure in chronic back pain sufferers up to 8 years after treatment. The findings contribute to an understanding of the sustainability of psychological cognitive behavioural therapy-based intervention effects.