Is acupuncture effective for the treatment of chronic pain? A systematic review

Pain is the major complaint of the estimated one million U.S. consumers who use acupuncture each year. Although acupuncture is widely available in chr onic pain clinics, the effectiveness of acupuncture for chronic pain remain s in question. Our aim was to assess the effectiveness of acupuncture as a treatment for chronic pain within the context of the methodological quality of the studies. MEDLINE (1966-99), two complementary medicine databases, 6 9 conference proceedings, and the bibliographies of other articles and revi ews were searched. Trials were included if they were randomized, had popula tions with pain longer than three months, used needles rather than surface electrodes, and were in English. Data were extracted by two independent rev iewers using a validated instrument. Inter-rater disagreements were resolve d by discussion. Fifty one studies met inclusion criteria. Clinical heterog eneity precluded statistical pooling. Results were positive in 21 studies, negative in 3 and neutral in 27. Three fourths of the studies received a lo w-quality score and low-quality trials were significantly associated with p ositive results (P = 0.05). High-quality studies clustered in designs using sham acupuncture as the control group, where the risk of false negative (t ype LI) errors is high due to large sample size requirements. Six or more a cupuncture treatments were significantly associated with positive outcomes (P = 0.03) even after adjusting for study quality. We conclude there is lim ited evidence that acupuncture is more effective than no treatment for chro nic pain; and inconclusive evidence that acupuncture is more effective than placebo, sham acupuncture or standard care. However, we have found an impo rtant relationship between the methodology of the studies and their results that should guide future research. (C) 2000 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved.