'Pacing' for management of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): a systematic review and meta-analysis

Background: Pacing typically comprises regulating activity to avoid post-exertional neuroimmune exhaustion, the worsening of symptoms after an activity. Yet, the efficacy of pacing to improve symptomology is unclear. Objective: We aimed to undertake a PRISMA-accordant meta-analysis concerning the effect of pacing on ME/CFS patients' symptoms. Data sources: Six electronic databases (PubMed, Scholar, ScienceDirect, Scopus, Web of Science and the Cochrane Central Register of Controlled Trials [CENTRAL]) were searched; and websites MEPedia, Action for ME, and ME Action were also searched for grey literature. Study selection: Studies (k = 5) selected from the 210 identified included randomised controlled trials (RCTs; k = 2), uncontrolled trials (UCTs; k = 1), intervention case series (k = 1), and sub-analysis of the PACE trial (k = 1), all of which had a pacing component, and an outcome measure reported pre- and post-pacing. Study appraisal and methods: Three separate meta-analyses were conducted on changes in symptoms using standardised mean differences (SMDs) and random-effects models. Results: The overall SMD showed pacing improved physical function (k = 4, SMD = 0.15 [95% CI = -0.39, 0.68], p = 0.5951). Pacing improved pain (k = 4, SMD = -0.11 [95% CI = -0.32, 0.10], p = 0.3090). Pacing improved fatigue (k = 4, SMD = -1.09 [95% CI = -2.38, 0.21], p = 0.0998). Conclusions: Pacing exerted a trivial beneficial effect on physical function and pain. Fatigue was improved with a large effect, which did reach the p < 0.05 level. We cautiously conclude pacing likely exerts some beneficial effects on symptomology, particularly, fatigue, in people with ME/CFS. However, the level of empirical research is insufficient, and more high-quality RCTs are essential to support the NICE guidelines.