The state of evidence in acupuncture: A review of meta-analyses and systematic reviews of acupuncture evidence (update 2017-2022)

This comprehensive review represents the most recent and broadest mapping of scientific evidence in acupuncture, systematically analyzing 862 systematic reviews and meta-analyses published between 2017 and 2022. The study was conducted by the SMS (International Society for Chinese Medicine) in Germany, rigorously following criteria established by earlier evidence-mapping projects.

The methodology involved a systematic PubMed search using the term "acupuncture," filtered for systematic reviews and meta-analyses. Two independent reviewers evaluated each study across three principal dimensions: quality of review (QoR), quality of data (QoD), and quality of evidence (QoE). Results were categorized into four levels: evidence of positive effect, evidence of potentially positive effect, insufficient/unclear evidence, and absence of evidence of effect.

The results revealed an encouraging picture for acupuncture. Ten medical conditions demonstrated robust evidence of positive effect: chronic pain, low back pain, knee osteoarthritis, postoperative nausea and vomiting, migraine, tension-type headache, cancer-related fatigue, menopausal symptoms, female infertility (as adjunctive treatment), and chronic prostatitis/chronic pelvic pain syndrome in men. These conditions now have solid scientific evidence justifying the clinical use of acupuncture.

Another 82 medical conditions showed evidence of potentially positive effect, including depression, insomnia, asthma, fibromyalgia, hypertension, and various neurological and oncologic conditions. Although the evidence is promising, the researchers consider that more high-quality studies are needed for definitive conclusions.

For 86 conditions, the evidence remained insufficient or unclear, mainly due to the low quality of primary studies or conflicting data among different reviews. Only six conditions showed a clear absence of evidence of efficacy, including infantile colic, neuropathic pain, and certain other specific conditions.

Compared with earlier reviews, there was a significant increase in both the quantity and the quality of evidence. The number of medical conditions with higher levels of evidence grew substantially since 2017, reflecting improvements in research methodology and greater rigor in clinical studies. This progress is partly attributed to methodological training programs for Chinese researchers funded by the German Research Foundation between 2010-2015.

The findings have important clinical implications. For the ten conditions with strong evidence, acupuncture can be considered an evidence-based therapeutic option. For the 82 conditions with potentially positive evidence, acupuncture represents a promising alternative, particularly when conventional treatments are inadequate or contraindicated.

However, the study acknowledges important limitations. The concept of sham or placebo acupuncture remains controversial, as studies suggest that controls considered inert may have their own therapeutic effects, leading to underestimation of the true effects of real acupuncture. Additionally, the wide diversity of techniques, traditions, and approaches in acupuncture makes direct comparisons across studies difficult.

The study emphasizes the need for greater methodological rigor in future research, recommending strict adherence to STRICTA and CONSORT guidelines. Standardization of outcome parameters, appropriate controls, and treatment protocols will be crucial for continuing to advance the evidence base for acupuncture and to facilitate cross-study comparisons.