Adverse effects associated with acupuncture therapies: An evidence mapping from 535 systematic reviews

This evidence mapping represents the most comprehensive survey of acupuncture-related adverse events ever conducted, analyzing 535 systematic reviews published through June 2022. The study was conducted by Chinese researchers and followed rigorous methodology, including searches in four major databases and assessment of methodological quality using the AMSTAR-2 tool.

The methodology involved systematic searches in PubMed, Embase, Web of Science, and the Cochrane Library, in addition to a supplementary search in Epistemonikos. Inclusion criteria covered systematic reviews in English that reported adverse events associated with any acupuncture technique, from electroacupuncture to auriculotherapy and specialized techniques such as scalp acupuncture.

The results revealed 33 different types of adverse events, classified into five main categories. The most prevalent category was "other adverse events" (373 studies), followed by organ or tissue injury (233 studies), systemic reactions (113 studies), fainting/syncope (86 studies), and infections (19 studies). The most frequently reported events included pain at the application site (144 studies, 11.79%), bleeding or hematoma (120 studies, 9.83%), dizziness (86 studies, 7.04%), and hematoma (70 studies, 5.73%).

The study identified 19 different acupuncture techniques associated with adverse events, with electroacupuncture being the most frequently studied (67 studies), followed by manual acupuncture (47 studies) and acupoint thread embedding (41 studies). The conditions treated spanned 23 disease categories according to ICD-11, with the highest prevalence in symptoms and clinical findings (83 studies), mental and behavioral disorders (67 studies), and diseases of the nervous system (66 studies).

Geographic analysis showed predominance of studies conducted in China (336 studies), followed by South Korea (90 studies) and the United States (30 studies). The methodological quality assessment revealed that most studies were of low or critically low quality, with only 22 studies classified as high quality and 28 as moderate quality.

Serious adverse events were rare, with the incidence of serious events estimated at approximately 0.001%. Most reported events were mild and transient, such as local pain, minor bleeding, or vasovagal reactions. Infectious events, although reported, have decreased significantly with the widespread adoption of aseptic techniques and the use of disposable needles.

The clinical implications are important for professionals and patients. The study confirms that acupuncture is a relatively safe intervention when practiced by trained professionals, with a favorable safety profile compared with conventional medications. Most adverse events can be prevented through adequate aseptic technique, appropriate anatomical knowledge, and proper patient preparation.

Limitations include the predominantly low methodological quality of the included studies, the search limited to English-language databases, and the frequently inadequate descriptions of adverse events in primary studies. Many reviews only described events qualitatively without appropriate statistical analyses.