Evidence A - Z
Welcome to the A-Z of the evidence base for acupuncture. These fact sheets are produced to provide accurate and unbiased general information for a variety of conditions. They provide summaries of research and how acupuncture may be beneficial. You should always consult your GP if you have any concerns or talk to a BAcC registered acupuncturist.
The fact sheets have three sections:
Summary: a summary of the currently available evidence
Commentary: assessment of the acupuncture and placebo interventions used in key clinical trials
Evidence: results of systematic reviews and clinical trials
Please note that we are currently undertaking a major review to update and broaden the information contained within the fact sheets.
For those of you who are unfamiliar with clinical research related to acupuncture, please take time to read the information below.
The evidence pyramid
The evidence pyramid is a commonly used diagram which illustrates how different types of evidence relate to each other and their relative strengths. A simple version of the evidence pyramid can be seen in Figure 1. At the bottom of the pyramid sit the weaker types of evidence, expert opinion followed by observational studies. The stronger types of evidence are towards the top, randomised controlled trials (RCT) followed by systematic reviews.
Systematic reviews try to answer the question: does therapy X work for condition Y? Normally, systematic reviews will only include RCTs, the higher quality evidence, and exclude observational studies. They are called systematic because they should use a systematic method of searching for trials and evaluating them. Ideally a systematic review will contain a meta-analysis where the results of the RCTs are combined to produce an overall result.
Systematic reviews should evaluate the ‘risk of bias’ from the included clinical trials. There are several things that may lead to bias. These include the methods used to randomise participants into different groups eg treatment or placebo group; and blinding, ensuring the participants cannot guess which group they are in. Reviews may also evaluate other aspects of evidence. The overall quality of the evidence can then be rated as high, moderate, low, and very low. This is known as the GRADE approach. Essentially, this is a measure of how confident the reviewers are in the result. And ultimately this depends upon the available evidence. To draw a firm conclusion a sufficient number of well-designed clinical trials must be available.
Clinical guidelines provide recommendations to healthcare professionals regarding the different options for a particular condition. The National Institute for Health and Care Excellence (NICE) and The Scottish Intercollegiate Guidelines Network (SIGN) produce clinical guidelines in the UK. A systematic review is conducted to gather all the evidence. Clinical guidelines will often base their recommendations not just on whether a therapy is effective but also on a cost-benefit analysis.
Systematic reviews of acupuncture
There are three main challenges when evaluating the evidence for acupuncture:
- availability of clinical trials
- the placebo
- quality of the acupuncture
Availability of clinical trials
The statement ‘there is no evidence that acupuncture is effective for condition Y’ can mean two different things. Clinical trials have been conducted and the results were negative. Alternatively, it means that no, or very few, high-quality clinical trials have been conducted.
Acupuncture research is dependent on charity and state funding, and conducting clinical trials is expensive. Consequently, for many conditions the available evidence is rather limited. The clinical trials are often small, involving less than 100 participants. This problem is reflected in the internationally renowned systematic reviews of the Cochrane Library. There are currently around 50 Cochrane reviews for acupuncture and various conditions. Many of these reviews, indicate that there is not sufficient evidence to draw a firm conclusion.
A placebo should look and feel exactly like the real treatment, so that the patient does not know which treatment they are getting. Ideally, the person who administers the treatment should also not know whether it is a placebo or the real treatment. This is the meaning of ‘double-blinded’ clinical trial. This is difficult for acupuncture, because it requires inserting needles into people without them knowing whether the needle has been inserted or not. In addition, it means the acupuncturist should not know if the needle has been inserted.
Different methods have been used to blind the participants in acupuncture trials, these are normally referred to as sham acupuncture. Whether these sham acupuncture methods are inert or have therapeutic effects beyond the psychological is a controversy within acupuncture research. For further reading on why these should not be considered inert interventions see Appleyard et al 2014.
Sham acupuncture trials are single blinded because the acupuncturist knows whether sham or real acupuncture is being administered. This means even high-quality trials may be assessed as having a risk of bias. Acupuncture is not alone in this respect, placebo controls are also difficult for other interventions such as surgery, exercise and talking therapies. In recent years, there have been calls for greater emphasis to be placed upon pragmatic research. Pragmatic research compares different interventions, for example, acupuncture vs medication or acupuncture vs physiotherapy.
Quality of the acupuncture
The acupuncture provided within some clinical trials would not be considered best practice by many BAcC members. For example, sometimes the number of treatments is inadequate, only providing one or two treatments when really 10 would be more appropriate. Sometimes the acupuncture points used are not sufficient or appropriate.
For many conditions more clinical trials will need to be conducted before researchers can be confident in their conclusions. The combined effect of active sham acupuncture and inadequate acupuncture potentially reduces the effect size. In other words, clinical trials will tend to underestimate the effect of acupuncture compared to placebo.
Acupuncture in clinical guidelines
Acupuncture is currently included in the following NICE guidelines:
- Headaches in over 12s: diagnosis and management (CG150)
- Chronic pain (primary and secondary) in over 16s: assessment of all chronic pain and management of chronic primary pain (CG193)
A key systematic review
In recent years high-quality clinical trials investigating acupuncture have been conducted, particularly for chronic pain conditions. Therefore, there is evidence available, and the systematic reviews can draw firm conclusions. A systematic review of high-quality trials, Vickers et al 2018, involving over 20,000 adults with osteoarthritis, chronic headache or musculoskeletal pain (back, neck or shoulder) concluded:
- Acupuncture was more effective than control for all pain conditions (pragmatic trials)
- Acupuncture is not a placebo for treatment of chronic pain
- The effects persisted over time (15% reduction at one year)
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