The placebo effect and its determinants in fibromyalgia: a systematic review and meta-analysis of randomised controlled trials

Chen, Xi (2015) The placebo effect and its determinants in fibromyalgia: a systematic review and meta-analysis of randomised controlled trials. PhD thesis, University of Nottingham.

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Introduction: Placebo has been proven effective in many diseases but whether it is effective in the treatment of fibromyalgia, a chronic widespread pain condition affecting 2% of general population, is unknown.

Objectives: [1] to determine whether placebo is effective for fibromyalgia; [2] to identify the possible determinants of the placebo effect [3] to gain knowledge around placebo effect, including nocebo effect and placebo response in difference conditions.

Method: Literatures were searched for randomised controlled trials that included placebo as a treatment or comparator in people with fibromyalgia. The placebo effect was measured as the improvement of pain and other outcomes from baseline. The effect was compared with no treatment control group or waiting list group. Meta-analysis was undertaken to combine data from different studies. Subgroup analysis was conducted to identify possible determinants of the placebo effect.

Results: 3375 studies were found from the literature search. After scrutiny, 204 trials met the inclusion criteria. Participants who took placebo in the trials had significant improvement in pain, fatigue, sleep quality, physical function, and other main outcomes, while participants in the no treatment controlled group stayed unchanged. The effect size of placebo in pain relief is clinically moderate (ES=0.47, 95%CI 0.37 to 0.56). The effect increased with the strength of the active treatment in the trials, participants’ age and baseline pain severity, but decreased in women and with longer duration of disease.

Conclusion: Placebo per se is effective in the treatment of fibromyalgia. The effect varies upon context, suggesting that the treatment effect in fibromyalgia depends on context which may be enhanced with the alternation of non-specific or contextual factors.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Zhang, W.
Doherty, M.
Keywords: Treatment of fibromyalgia, Placebo, Pain relief
Subjects: W Medicine and related subjects (NLM Classification) > WE Muscoskeletal system
Faculties/Schools: UK Campuses > Faculty of Medicine and Health Sciences > School of Medicine
Item ID: 28254
Depositing User: CHEN, Xi
Date Deposited: 30 Sep 2015 08:16
Last Modified: 15 Dec 2017 19:56

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