[Acupuncture in fibromyalgia: a randomized, controlled study addressing the immediate pain response].

OBJECTIVE To evaluate the efficacy of acupuncture in the treatment of fibromyalgia, considering the immediate response of the visual analogue pain scale (VAS) as its primary outcome. METHODS Randomized, controlled, double-blind study including 36 patients with fibromyalgia (ACR 1990) selected from the outpatient rheumatology clinic, Santa Casa de Misericórdia, Ponta Grossa, PR. Twenty-one patients underwent an acupuncture session, under the principles of the traditional Chinese medicine, and 15 patients underwent a placebo procedure (sham acupuncture). For pain assessment, the subjects completed a Visual Analogue Scale (VAS) before and immediately after the proposed procedure. The mean change in VAS was compared among groups. RESULTS The variation between the final and initial VAS values was -4.36±3.23 (P=0.0001) in the treatment group and -1.70±1.55 in the control group (P=0.06). The difference in terms of amplitude of variation of VAS (initial - final VAS) among groups favored the actual procedure (P=0.005). The effect size (ES) for the treatment group was d=1.7, which is considered a large effect. Although small, the statistical power of the sample for these results was very relevant (94.8%). CONCLUSION Acupuncture has proven effective in the immediate pain reduction in patients with fibromyalgia, with a quite significant effect size.