Exposure in vivo versus operant graded activity in chronic low back pain patients: Results of a randomized controlled trial

TLDR

Pain‑related fear is thought to contribute to chronic low back pain, prompting the development of an exposure‑in‑vivo treatment. The study examined the effectiveness and mediating mechanisms of exposure‑in‑vivo versus operant graded activity in chronic low back pain patients. Eighty‑five patients with disabling non‑specific CLBP and moderate pain‑related fear were randomized to EXP or GA in a multi‑centre trial. EXP lowered pain catastrophizing and perceived harmfulness of activities more than GA, yet both groups achieved similar improvements in functional disability, main complaints, pain intensity, and daily activity, with about half the patients showing clinically relevant gains and the benefits on disability and complaints mediated by reductions in catastrophizing and perceived harmfulness.

Abstract

Since pain-related fear may contribute to the development and maintenance of chronic low back pain (CLBP), an exposure in vivo treatment (EXP) was developed for CLBP patients. We examined the effectiveness as well as specific mediating mechanisms of EXP versus operant graded activity (GA) directly and 6 months post-treatment in a multi-centre randomized controlled trial. In total, 85 patients suffering from disabling non-specific CLBP reporting at least moderate pain-related fear were randomly allocated to EXP or GA. It was demonstrated that EXP, despite excelling in diminishing pain catastrophizing and perceived harmfulness of activities, was equally effective as GA in improving functional disability and main complaints, although the group difference almost reached statistical significance favouring EXP. Both treatment conditions did not differ in pain intensity and daily activity levels either. Nor was EXP superior to GA in the subgroup of highly fearful patients. Irrespective of treatment, approximately half the patients reported clinically relevant improvements in main complaints and functional disability, although for the latter outcome the group difference was almost significant favouring EXP. Furthermore, the effect of EXP relative to GA on functional disability and main complaints was mediated by decreases in catastrophizing and perceived harmfulness of activities. In sum, this study demonstrates that up to 6 months after treatment EXP is an effective treatment, but not more effective than GA, in moderately to highly fearful CLBP patients, although its superiority in altering pain catastrophizing and perceived harmfulness of activities is clearly established. Possible explanations for these findings are discussed.