The efficacy of a brief acceptance-based group intervention in a sample of female patients with fibromyalgia and comorbid obesity: a randomised controlled trial

Objectives: A two-arm parallel randomised controlled trial was conducted to evaluate the efficacy of a group acceptance-based treatment (ABT) in improving pain acceptance, pain catastrophising, kinesiophobia, pain intensity and physical functioning compared to treatment as usual in patients with fibromyalgia (FM) and comorbid obesity. Methods: Female individuals diagnosed with FM and obesity (n = 180) were randomly assigned to either a three-weekly group acceptance-based treatment plus treatment as usual (ABT+TAU) or only TAU. The variables of interest were assessed at baseline (T0) and after the interventions (T1). The treatment protocol for the ABT+TAU condition, designed for an inpatient rehabilitation context, is based on acceptance and commitment therapy but focuses specifically on pain acceptance, a crucial factor in fostering a more functional adaptation to chronic pain. Results: Participants in the ABT+TAU group showed significant improvements in pain acceptance (i.e. the primary outcome), but also in pain catastrophising, kinesiophobia, and performance-based physical functioning (i.e. the secondary outcomes) compared to those in the TAU group. However, there were no significant differences in pain intensity between the two groups. Conclusions: These findings indicate that a brief group-based ABT intervention is effective in enhancing pain acceptance, reducing pain catastrophising and kinesiophobia, and improving performance-based physical functioning. Furthermore, the observed improvements in kinesiophobia and physical functioning may have particular relevance for individuals with comorbid obesity, as they can facilitate greater adherence to physical activity and promote weight loss.