Effects of acupuncture versus placebo on clinical status and potential specific effects in fibromyalgia: an umbrella review of 11 meta-analyses

Background: the use of acupuncture is related to patients' expectations, and the therapeutic interaction effect remains a topic of debate in the literature. Accordingly, it is still unclear whether acupuncture can generate positive clinical effects in patients with fibromyalgia (FM). Objective: to determine the effectiveness of acupuncture versus placebo for clinical outcomes and determine the overall effect not attributed to specific effects in patients with FM. Design: umbrella review of systematic reviews (SRs) and meta-analyses. Data sources and methods: an electronic search was performed in MEDLINE (via PubMed), Web of Science, CENTRAL, EMBASE, LILACS, CINAHL, PEDro, and SPORTDiscus databases from inception until December 2023. We selected studies with a clinical diagnosis of FM and that analyzed the effectiveness of acupuncture compared with a placebo. Pain intensity, functional status, fatigue, sleep quality, and depression symptoms were assessed. Effect sizes were calculated as the mean difference (MD) or standard mean difference (SMD). The quality of intervention reporting was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach. Results: Eleven SRs with 8399 participants were included. Compared with placebo, acupuncture was associated with reductions in pain intensity (MD = -1.13 cm, 95% CI -2.09 to -0.17, p < 0.001), physical function (SMD = -0.63, 95% CI -1.67 to 0.41, p = 0.06), sleep quality (SMD = -0.25, 95% CI -1.39 to 0.88, p = 0.06), and fatigue (SMD = 0.20, 95% CI = 0.17 to 0.22, p < 0.001). The proportion not attributable to specific effects (PCE) of acupuncture was 58% for pain intensity (PCE = 0.58, 95% CI 0.45 to 0.71), 57% for physical function (PCE = 0.57, 95% CI -0.07 to 1.20), and 69% for fatigue (PCE = 0.69, 95% CI 0.18 to 1.21). Conclusion: acupuncture showed a statistically significant difference in decreased pain intensity and fatigue in women with FM. However, the certainty of evidence was low to very low; its effects are not clinically important, and more than 50% of the overall treatment effects were not attributed to the specific effects of acupuncture.