The efficacy, acceptability and safety of acceptance and commitment therapy for fibromyalgia - a systematic review and meta-analysis

Background: Fibromyalgia (FM) is a chronic pain disorder characterised by widespread pain, fatigue and cognitive symptoms. Acceptance and commitment therapy (ACT) aims to improve psychological flexibility and has been found to be beneficial in treating chronic pain; however, there are few studies evaluating its efficacy in treating FM. Aim: This systematic review and meta-analysis evaluated the efficacy of acceptance and commitment therapy in patients with fibromyalgia. Methods: PubMed, Embase and PsychInfo databases were searched. Randomised Controlled Trials (RCTs) were eligible for inclusion if participants had FM, and the intervention was based on the ACT framework/ model, and not combined with any other active therapy; any non-ACT control was accepted. A meta-analysis was performed, with the primary outcomes pain acceptance (chronic pain acceptance questionnaire, CPAQ), health-related quality of life (fibromyalgia impact questionnaire, FIQ), attrition rate and frequency of adverse events, and the secondary outcomes pain intensity, disability, depression, anxiety, and fatigue. Results: Six RCTs, with a total of 384, mostly-female, participants were included, with ACT being delivered online, in a group setting, or one-to-one. ACT was superior to controls in improving FIQ score at postintervention (SMD -1.05, 95% CI -2.02, -0.09) and follow-up (SMD -1.43, 95% CI -2.17, -0.69) and CPAQ post-intervention (SMD 1.05, 95% CI 0.61, 1.49) and at follow-up (SMD 0.95, 95% CI 0.40, 1.49). Attrition was below 20% in 4/6 studies and no adverse events were reported as attributable to ACT. All secondary outcomes showed large-to-moderate pooled effect estimates post- intervention, indicating improvement in anxiety, depression, pain and disability. Fatigue also improved, with a large negative effect. Conclusions: The results suggest ACT improved outcomes in patients with FM: there was an overall improvement in all outcomes post-intervention, with most maintained at follow-up. This review was, however, limited by the small body of evidence and differing methodologies of included studies.