Recent trends in acupuncture for chronic pain: A bibliometric analysis and review of the literature

Chronic pain represents one of the major global public health challenges, affecting approximately 28% of adults worldwide and costing healthcare systems hundreds of billions of dollars annually. Defined by the International Association for the Study of Pain as pain that persists for more than three months, often accompanied by emotional and functional disturbances, chronic pain significantly impacts patients' quality of life. Conventional drug treatment, especially with opioids, has serious limitations due to severe side effects, including physical dependence, tolerance, and overdose risk. In this context, acupuncture has emerged as a promising complementary therapy, demonstrating efficacy in relieving various types of chronic pain and potential to reduce opioid analgesic use.

Growing scientific interest in this area motivated the need for a comprehensive analysis of the research landscape on acupuncture for chronic pain.

This study aimed to map and analyze the characteristics, key points, and trends of global scientific output on acupuncture for chronic pain over the past decade. The investigators used a methodology called bibliometric analysis, which allows quantitative examination of large volumes of scientific literature. They searched for articles published between 2011 and 2022 in the Web of Science database, using terms related to acupuncture and various types of chronic pain. After a rigorous selection process, 1,616 articles were included for analysis.

The investigators used specialized software (VOSviewer and CiteSpace) to create visual maps of the relationships between countries, institutions, authors, journals, and keywords, allowing identification of collaboration patterns, main themes, and emerging trends in the field.

The results revealed consistent growth in the number of publications on acupuncture for chronic pain, rising from 70 articles in 2011 to 227 in 2021, with a peak of 246 publications in 2020. China leads scientific output by a wide margin with 598 articles (37% of the total), followed by the United States (173 articles), South Korea (100 articles), and other countries. Among institutions, Chinese universities of traditional medicine occupy the top positions, with the Beijing University of Chinese Medicine leading with 93 publications. The most productive researcher was Liang FR, with 43 published articles.

The journal 'Evidence-based Complementary and Alternative Medicine' published the most studies in the field. The most frequent themes included electroacupuncture, pain management, therapeutic efficacy, and systematic reviews. The analysis identified four major thematic clusters: experimental design, prevalent diseases (such as knee osteoarthritis, chronic low back pain, and neuropathic pain), therapeutic interventions, and mechanism studies.

The findings have important clinical implications for both patients and healthcare professionals. The research demonstrates that there is a growing and robust body of scientific evidence supporting the use of acupuncture for various chronic pain conditions. For patients, this means greater confidence in acupuncture as a legitimate therapeutic option, especially when conventional treatments have limitations or undesired side effects. The study identified that acupuncture has been shown to be effective for specific conditions such as migraine, knee osteoarthritis, chronic low back pain, and neuropathic pain.

The analysis also revealed important emerging trends, such as the growing use of neuroimaging to understand the brain mechanisms of acupuncture analgesia, and the growing attention to the relationship between chronic pain and depression. For health professionals, the results suggest the importance of considering acupuncture as part of integrated approaches to chronic pain treatment, especially given its potential to reduce dependence on opioid medications.

The study presents some important limitations that should be considered when interpreting the results. First, the analysis was based exclusively on the Web of Science database, excluding publications in other databases and languages other than English, which may have resulted in the omission of relevant studies, especially from non-English-speaking countries. Second, although the analysis period was defined as 2011-2022, data collection was performed in June 2022, potentially missing publications from the second half of that year. Third, bibliometric analysis, by its quantitative nature, does not assess the individual methodological quality of included studies.

The study also revealed that, despite the growing volume of research, there is still a need to strengthen international collaboration and improve the methodological quality of studies, especially with regard to the design of randomized controlled trials. The trends identified — such as the growing focus on functional brain connectivity and the pain-depression relationship — point to promising directions for future research that may deepen our understanding of acupuncture's mechanisms and optimize its clinical application.