There have been many randomized trials and systematic reviews of acupuncture as a treatment for a variety of health conditions. Most of these reviews, however, have concluded that their confidence in the effect of acupuncture was limited. Veterans Affairs researchers sought to create an updated evidence map to help policymakers and clinicians evaluate the certainty or quality of evidence in recent systematic reviews of acupuncture for adult health conditions.

Of the 434 systematic reviews of acupuncture that were identified, 127 used a formal method to rate the certainty or quality of evidence of their conclusions, and 82 were mapped. In almost all the mapped reviews, manual or standard acupuncture was the intervention. For ease of reading and ability to find a particular condition, the conditions were divided into three different maps: pain, mental health conditions, and other conditions.

The researchers found that only four reviews of acupuncture (for fertility, fibromyalgia, shoulder pain, and stroke) had at least one conclusion rated as high-certainty evidence. More had at least one conclusion rated as moderate-certainty evidence, but most had all conclusions rated as low- or very-low-certainty evidence. Approximately 75% of the systematic reviews in which the original authors graded the certainty of evidence as moderate were comparing acupuncture with sham or control acupuncture or with no treatment, and most were for painful conditions. According to the authors, acupuncture appeared to be at least as safe or safer than usual care.

Some studies may have been missed, the authors note, and they didn't independently evaluate the source evidence. They also point out that assessing the outcomes of acupuncture is challenging because of the variation with which sham acupuncture is designed and the lack of clear understanding about the exact mechanism by which acupuncture is effective.