In order to answer this question, we need first to clearly define our terms. ‘Evidence-based’ is quite straightforward – applying the best available evidence gained from the scientific method to clinical decision making. On the other hand, CAM has a number of definitions; the National Center for Complementary and Alternative Medicine (NCCAM) definition is probably as good as any, which defines CAM as ‘. . . a group of diverse medical and health care systems, practices, and products that are not generally considered part of conventional medicine’.1 There are hundreds of CAM therapies, which can be conveniently divided into five subgroups:
- • Alternative medical systems (e.g. homeopathy, TCM).
- • Manipulative and body-based practices (e.g. chiropractic, massage therapy).
- • Mind-body therapies (e.g. art therapy, yoga, meditation).
- • Biologically based therapies (e.g. vitamins, herbs, diets, supplements).
- • Energy medicine [e.g. magnetic therapy, transcutaneous electrical nerve stimulation (TENS)].
Opinions on CAM therapies are usually strongly held and polarised. Advocates and proponents argue passionately that many if not most CAM therapies can be beneficial, even if this has not been demonstrated in clinical research. Sceptical opponents of CAM can be equally vociferous in their opinions and, for many therapies, I would agree. I have been an outspoken critic of biologically implausible CAM therapies with no good clinical research evidence, including homeopathy, chiropractic for non-musculoskeletal disorders, ear candling, magnetic therapy, health wristbands and others. But, it is important that sceptics remain open-minded and are prepared to change their mind when presented with good evidence. Some therapies, admittedly only a dozen or two out of the hundreds of CAM therapies that are available, do have reasonable or even strong research evidence to support their use, and so evidence-based CAM is not a contradiction in terms for these therapies or products.
Before briefly highlighting the evidence for such therapies and products, let us not forget that around half of the prescription medicines that we commonly use have their origins in the natural world, either purified from the raw material (e.g. digitalis) or chemically modified (e.g. captopril). The extract of purple foxglove would be considered a CAM therapy, whereas the slightly more refined digitalis is a pharmaceutical. The same applies for Salix spp. (white willow) extract and aspirin. . . . I would guess that my debating opponent uses the latter! Many anaesthetic agents, painkillers and antibiotics, to name just a few classes of pharmaceuticals, have their origins in the natural world and the raw materials are often classified as CAM.
And whilst it has been argued that ‘if CAM therapies or products worked they would be part of standard medical practice’, this is not necessarily the case. It can often take around 10 years from when research is published until a treatment becomes part of routine clinical practice; longer still with CAM therapies, if they get accepted at all. More importantly, CAM therapies with the strongest evidence (e.g. omega-3 fish oil for the prevention of coronary heart disease, or TENS for neural pain), which have ‘graduated’ into routine clinical practice, may no longer be thought of as CAM.
Thousands of papers are published on CAM therapies each year. Many, if not the vast majority of studies, are admittedly of poor quality and add little if anything in terms of robust clinical evidence. The field is rife with pilot studies, epidemiological research, in-vitro experiments, animal studies, case reports and non-controlled studies. Such research is, at best, a starting point for well-designed, controlled clinical trials. CAM therapy research does have challenges in addition to those faced by pharmaceutical research, not least of which is a lack of patent protection, the result of which is usually a lack of funds for expensive trials. But this is not to let CAM therapies off the hook – good studies must be undertaken before such therapies can be recommended.
Bearing all of the above in mind, the following are brief summaries of just a few studies that undoubtedly constitute evidence-based CAM:
- • A study of the use of Zingiber spp. (ginger) in 644 patients with chemotherapy-induced nausea and vomiting found ginger supplementation, at a dose of 0.5–1.0 g daily, significantly reduced nausea during the first day of chemotherapy.2
- • A meta-analysis of medical honey for burns found markedly greater efficacy of honey compared with alternative dressing treatments for superficial or partial thickness burns.3
- • A meta-analysis of Coenzyme Q10 for hypertension found Coenzyme Q10 had the potential in hypertensive patients to lower systolic blood pressure by up to 17 mmHg and diastolic blood pressure by up to 10 mmHg, without significant side-effects.4
- • A meta-analysis of Hypericum perforatum (St John's wort) in depression, which included 22 RCTs, showed H. perforatum to be significantly more effective than placebo, and not significantly different in efficacy from pharmaceutical antidepressants.5
- • A large RCT comparing the effects of omega-3 fish oil to fluoxetine in people with major depression found fish oil and fluoxetine had approximately equal therapeutic effects in major depressive disorder.6
- • A systematic review of massage therapy in patients with cancer showed massage therapy to be effective in improving patient anxiety, pain, nausea, sleep and overall QoL.7
- • A review of six clinical studies examining the efficacy of capsaicin in patients with chronic pain found the topical application of capsaicin to be useful for some patients who are unresponsive to, or intolerant of, other treatments.8
The studies described above are either large RCTs, systematic reviews or meta-analyses of RCTs – the highest levels of evidence in medical research. The therapies can all be defined as CAM, although some have or may well soon ‘graduate’ into routine clinical practice. The study of ginger in patients with chemotherapy-induced nausea and vomiting included over 600 participants, and not only demonstrated efficacy but also determined the dose-response relationship and side-effect profile. This study was therefore of an equivalent standard to some of the best clinical trials of pharmaceuticals.
Future studies will almost certainly show more CAM therapies to be safe and effective and, importantly, could even help with some of the most difficult problems in modern medicine. For example, it is possible that some CAM therapies may be shown to be as safe and effective as expensive pharmaceuticals, but at a fraction of the cost, thereby easing the pressure on overburdened health services. Another example would be methicillin-resistant Staphylococcus aureus (MRSA) infection which, by definition, is difficult and expensive to treat and yet medical-grade honey appears to be highly effective against.9,10
There is no doubt that there are some evidence-based CAM therapies and products, and almost certainly future studies will show more CAM therapies and products to be as effective, or even more effective and/or safer, than conventional treatments. Clinicians therefore need to be sceptical but open-minded in exactly the same way they would be for any new pharmaceutical or surgical treatment. Admittedly, evidence-based CAM therapies can be hard to find, often hidden in a sea of nonsensical therapies and poor quality research. But, simply dismissing all CAM therapies and products as lacking evidence is untrue and unscientific, and may result in patients not receiving other effective and safe treatments.