Functional status and overall improvement. "For improving functioning," the researchers observed, "acupuncture was statistically significantly more effective than the no-additional-treatment control in the short term effects." They added, "For overall improvement, acupuncture was statistically significantly more effective than the sham controls and no-additional-treatment control in both the short- and long-term effects."
Study quality. Of the 22 trials included in the final meta-analysis, only eight met the requirements for being a study of "good quality" according to both the Jadad and Cochrane criteria. Three studies received a Jadad score of four; none of the studies obtained a maximum Jadad score of five. The highest Cochrane score given to any of the trials was a seven (out of 10).
The authors noted that each of the control interventions used in the trials had certain advantages and limitations that had to be considered in interpreting the results of their analysis. For example, the studies that used sham acupuncture as a control generally reported less benefits compared to studies that used no additional treatment as a control. The authors theorized that sham acupuncture needles "may unintentionally stimulate a physiologic response" that could produce "some specific analgesic effects," especially when the sham needles penetrate the skin. In fact, all of the sham-controlled studies included in the meta-analysis involved needles that penetrated the skin at non-specific points.
Paucity of High-Quality Trials Raises Questions About Acupuncture's Effectiveness
Based on the data presented in the randomized trials, the authors suggested that acupuncture "is an effective treatment for chronic low back pain," particularly in terms of providing short-term relief of chronic low back pain. They were quick to add, however, that the data "are sparse and inconclusive" for patients with acute low back pain, and they reported being "uncertain" about acupuncture's ability to provide long-term relief of back pain. The reason for the uncertainty? Because, in the view of the researchers, "longer-term follow-up data are limited in quantity and quality."