Acupuncture Clinical Evidence
The term “evidence-based medicine” (EBM) first appeared in a paper in 1992. 1 In the late 1990s, EBM had emerged as the premier method of teaching and practicing medicine. EBM promotes the use of up-to-date “best” scientific evidence from healthcare research as the basis for making medical decisions. As acupuncture has been getting widely practiced not only in private clinics but also in many University hospitals, there has been a strong demand for scientific evidence to defend its safety and efficacy. Those calling for this testing point to the fact that stringent testing is required for the determining safety and efficacy of acupuncture. Under the EBM concept, high quality evidence means evidence derived from randomized controlled trials and systematic reviews.2
Over the past two thousand years, acupuncture has been used to treat a wide variety of illnesses.3 Technical skills and knowledge of acupuncture have been handed down from generation to generation, forming an empirical based medicine. Essential clinical information may be contained in such expert opinion, however the history of medicine, both conventional and alternative, has shown that such opinion can be unreliable or in some cases, completely wrong. There are so many theories, techniques, and protocols existing in acupuncture fields. It is time to re-visit all available information and filter down quality evidence that is meaningful in clinical practice for the benefit of patients.
Clinical Trials on Acupuncture
The vast majority of research papers in acupuncture until recent years are clinical case reports, which are considered low level of evidence based on the EBM concept.4
That is because case reports are uncontrolled studies, involving descriptions of the patient’s history, administered treatments and outcome. Even if the study was based on successful results on hundreds or thousands of patients; we really cannot tell how much, if any, administered therapeutic intervention contributed to improvements of the patient’s condition, without observation of a comparative patient population (otherwise known as a control group). For this reason, case reports are usually not accepted by reputable peer-reviewed journals for publication (unless the subject is involved in very rare cases).
A study by Haruto Kinosita of Japan in 19715 is probably the first randomized control clinical trial of acupuncture ever conducted. A clinical trial of acupuncture appeared in an English database in 19736 and since then, a growing number of controlled clinical trials have been conducted in the US and Europe. The greatest number of acupuncture studies have been conducted and published in China. However, the vast majority of the studies are non-controlled studies.
In previously conducted controlled trials, virtually all research trials suffered from methodological limitations. There are some difficulties when conducting acupuncture trials. For example, while EBM aims to establish the most appropriate treatment for large populations with the same clinical condition, the traditional concept of acupuncture is to establish treatment principles for each individual patient rather than disease populations. Another difficulty is the issue of an adequate control group and blinding both practitioners and patients when conducting a clinical trial of acupuncture. Unlike the double-blind drug trials, it is hard to blind the practitioners and patients in an acupuncture study. There have been many acupuncture trials using “sham” acupuncture, however, “sham” acupuncture used in many previous studies are not considered physiologically inert (it means there are potential therapeutic effects). Readers of those previous studies need to be fully aware of this fact, when interpreting the outcome of studies, in particular if a study found no statistical difference between the acupuncture group and the “sham” acupuncture group. In recent years, different types of placebo acupuncture needles have been invented.7-9 Single-blind 10 11 and even double-blind 12 studies are claimed to be possible using those placebo needles, however there are some considerable therapeutic limitations and restrictions involved with those needles.
Keeping in mind various issues surrounding acupuncture studies, it is still essential to conduct research and produce quality evidence. However, there is a need for utilizing new or modified research designs that can accommodate the unique, individually oriented nature of non-drug intervention such as acupuncture. Some research methodologies that are considered suitable for acupuncture studies are using stratified randomization according to each patients’ traditional East Asian medicinal diagnosis patterns. In addition, study design such as n-of-1 trial, which considers an individual’s unique characteristics, as well as their responses to interventions.13 14 Thus far this experimental design has primarily been used in psychology but its usage has been recently expanded and utilized in acupuncture research trials.15 16 An outcome of the n-of-1 RCT is considered high quality evidence. However the experimental design can be utilized only for patients that exhibit certain chronic conditions. It is not a suitable design to evaluate the efficacy of acupuncture for acute or episodic types of conditions.
Finally, the most important issue when interpreting outcomes from clinical research studies is the fact that acupuncture protocols used in many previous studies are far from those commonly used in clinical practice. When researchers plan the study, acupuncture protocols are determined not only by its potential efficacy but also by its experimental design, budgets, and other methodological factors. This generally results in compromised acupuncture treatments which become simple, short, and standardized protocol. The results derived from compromised acupuncture should not be automatically assumed to be the same as clinical acupuncture.
Systematic Reviews on Acupuncture
With the exception of very few recent trials that contain a large number of patients, e.g., 17-21 most of the previous acupuncture trials suffer from the drawback of a small sample size.
Thus, there are a substantial number of previous studies that are considered under-powered and the results may be contaminated by a Type II error (false negative). A systematic review attempts to systematically collect and analyze all published qualified clinical trials. All previous studies of the same topic including data from small studies are pooled together and analyzed as if they were one study (meta-analysis). Thus, the systematic review is considered to be of highest quality of evidence in EBM.
It should be kept in mind, however, that the existence of contradicting evidence is not unusual in any medical discipline. The systematic review attempts to minimize such bias by using pre-determined criteria to qualify previous studies, yet this process itself is subject to bias. It is therefore not uncommon to find contradicting conclusions from systematic reviews on the same research topic. Some researchers therefore, found it necessary to complete a “systematic review of systematic reviews”. 22-27
It is important to note that RCTs included in meta-analyses need to be conducted adequately with sufficient control and intervention protocols, otherwise, the conclusion of systematic review could be skewed. The issue of publication bias should be also mentioned. It has been indicated that certain countries tend to publish only positive studies.28 Nevertheless, the systematic review is considered the best evidence available in EBM, and healthcare practitioners and policy makers should pay close attention to these reviews.
1. Evidence-based medicine. A new approach to teaching the practice of medicine. Jama 1992;268(17):2420-5.
2. Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn’t. Bmj 1996;312(7023):71-2.
3. Gwei-Djen L, Needham J. Celestial Lancets: A History and Rationale of Acupunture and Moxa. London: Cambridge University Press, 1980.
4. Sackett DL. Evidence-based Medicine: How to Practice and Teach EBM. . 2nd edition ed: Churchill Livingtone, 2000.
5. Kinoshita H. Rinshoshiken karamita hosha no kentou. Nihon Shinkyu Chiryou Gakkai Shi 1971;6:6-13.
6. Gunsberger M. Acupuncture in the treatment of sore throat symptomatology. Am J Chin Med (Gard City N Y) 1973;1(2):337-40.
7. Park J, White A, Stevinson C, Ernst E, James M. Validating a new non-penetrating sham acupuncture device: two randomised controlled trials. Acupunct Med 2002;20(4):168-74.
8. Streitberger K, Kleinhenz J. Introducing a placebo needle into acupuncture research. Lancet 1998;352(9125):364-5.
9. Takakura N, Yajima H. A double-blind placebo needle for acupuncture research. BMC Complement Altern Med 2007;7:31.
10. Kleinhenz J, Streitberger K, Windeler J, Gussbacher A, Mavridis G, Martin E. Randomised clinical trial comparing the effects of acupuncture and a newly designed placebo needle in rotator cuff tendinitis. Pain 1999;83(2):235-41.
11. Tan CW, Christie L, St-Georges V, Telford N. Discrimination of real and sham acupuncture needles using the park sham device: a preliminary study. Arch Phys Med Rehabil 2009;90(12):2141-5.
12. Takakura N, Yajima H. Analgesic effect of acupuncture needle penetration: a double-blind crossover study. Open Med 2009;3(2):e54-61.
13. Guyatt GH, Heyting A, Jaeschke R, Keller J, Adachi JD, Roberts RS. N of 1 randomized trials for investigating new drugs. Control Clin Trials 1990;11(2):88-100.
14. Guyatt GH, Keller JL, Jaeschke R, Rosenbloom D, Adachi JD, Newhouse MT. The n-of-1 randomized controlled trial: clinical usefulness. Our three-year experience. Ann Intern Med 1990;112(4):293-9.
15. Jackson A, MacPherson H, Hahn S. Acupuncture for tinnitus: a series of six n = 1 controlled trials. Complement Ther Med 2006;14(1):39-46.
16. Kawakita K, Shichidou T, Inoue E, Nabeta T, Kitakoji H, Aizawa S, et al. Do Japanese style acupuncture and moxibustion reduce symptoms of the common cold? Evid Based Complement Alternat Med 2008;5(4):481-9.
17. Flachskampf FA, Gallasch J, Gefeller O, Gan J, Mao J, Pfahlberg AB, et al. Randomized trial of acupuncture to lower blood pressure. Circulation 2007;115(24):3121-9.
18. Macklin EA, Wayne PM, Kalish LA, Valaskatgis P, Thompson J, Pian-Smith MC, et al. Stop Hypertension with the Acupuncture Research Program (SHARP): results of a randomized, controlled clinical trial. Hypertension 2006;48(5):838-45.
19. Linde K, Streng A, Hoppe A, Brinkhaus B, Witt CM, Hammes M, et al. Treatment in a randomized multicenter trial of acupuncture for migraine (ART migraine). Forsch Komplementmed 2006;13(2):101-8.
20. Diener HC, Kronfeld K, Boewing G, Lungenhausen M, Maier C, Molsberger A, et al. Efficacy of acupuncture for the prophylaxis of migraine: a multicentre randomised controlled clinical trial. Lancet Neurol 2006;5(4):310-6.
21. Vickers AJ, Rees RW, Zollman CE, McCarney R, Smith CM, Ellis N, et al. Acupuncture for chronic headache in primary care: large, pragmatic, randomised trial. Bmj 2004;328(7442):744.
22. Derry CJ, Derry S, McQuay HJ, Moore RA. Systematic review of systematic reviews of acupuncture published 1996-2005. Clin Med 2006;6(4):381-6.
23. Ernst E. A systematic review of systematic reviews of homeopathy. Br J Clin Pharmacol 2002;54(6):577-82.
24. Ernst E, Canter PH. A systematic review of systematic reviews of spinal manipulation. J R Soc Med 2006;99(4):192-6.
25. Ernst E, Lee MS. Acupuncture for palliative and supportive cancer care: a systematic review of systematic reviews. J Pain Symptom Manage;40(1):e3-5.
26. Ernst E, Lee MS, Choi TY. Acupuncture for Depression? A Systematic Review of Systematic Reviews. Eval Health Prof.
27. Moore A, Jull G. The systematic review of systematic reviews has arrived! Man Ther 2006;11(2):91-2.
28. Vickers A, Goyal N, Harland R, Rees R. Do certain countries produce only positive results? A systematic review of controlled trials. Control Clin Trials 1998;19(2):159-66.
Basic Studies of Acupuncture – Laboratory Experiments
While the main research question in clinical trials of acupuncture is whether or not the therapy works for a particular health condition, basic studies of acupuncture aim to address the question of why and how it works.
Such studies attempt to elucidate the exact mechanisms and actions of acupuncture by conducting experiments under strict laboratory-controlled conditions.
Many basic studies are conducted using animal subjects (e.g., mice, rats, cats, or dogs); these subjects are usually anaesthetized. The subjects may be administered additional pharmacological agents to create a certain disease model. In some experiments, the animals undergo surgical procedures such as nerve dissection, so that the neural-signal transmission pathway can be isolated when somatosensory stimulation (i.e., acupuncture) is applied. In many basic studies, acupuncture is administered only on a single point, using a standardized stimulation method, in order to find out exactly which point and stimulation method are eliciting a particular response.
Although the results from experiments using anaesthetized animals are not always applicable to conscious human patients, highly clinically useful information has been produced through basic research experiments, especially over the last 30 years. Elucidating the mechanisms of acupuncture is vital for acupuncture’s further acceptance as a valid, science-based therapeutic modality.