Chiropractors have become (in)famous for making claims which contradict the known facts. One claim that we find with unfailing regularity is that “regular chiropractic treatments will improve your quality of life“. There are uncounted websites advertising this notion, and most books on the subject promote it as well, some are even entirely dedicated to the theme. Here is a quote from a typical quote from one site chosen at random: “Quality of life chiropractic care is the pinnacle of chiropractic care within the chiropractic paradigm. It does not solely rely on pain or postural findings, but rather on how a persons life can be positively influenced through regular adjustments… A series of regular adjustments is programmed and continual advice on life improvement is given. It is designed as a long term approach and gains its strength from the regularity of its delivery.”
Given the ubiquitous nature of such claims, and given the fact that many chiropractic clients have back problems which reduce their quality of life, and given that back pain is just about the only condition for which chiropractors might have something to offer, it seems relevant to ask the following question: what is the evidence that chiropractic interventions affect the quality of life of back pain sufferers?
Some time ago, an Italian randomised clinical trial compared chiropractic spinal manipulations with sham-manipulations in patients affected by back pain and sciatica. Its results were disappointing and showed “no significant differences in quality of life and psychosocial scores.” But this is just one (potentially cherry-picked) study, I hear my chiropractic friends object. What we quite clearly need, is someone who takes the trouble to evaluate the totality of the available evidence.
Recently, Australian researchers published a review which did just that. Its authors conducted thorough literature searches to find all relevant studies on the subject. Of the 1,165 articles they located, 12 investigations of varying quality were retained, representing 6 studies, 4 randomised clinical trial and two observational studies. There was a high degree of inconsistency and lack of standardisation in measurement instruments and outcome measures. Three studies reported reduced use of additional treatments as a positive outcome; two studies reported a positive effect of chiropractic interventions on pain, and two studies reported a positive effect on disability. The 6 studies reviewed concentrated on the impact of chiropractic care on physical health and disability, rather than the wider holistic view which was the focus of the review. On the basis of this evidence, the authors conclude that “it is difficult… to defend any conclusion about the impact of chiropractic intervention on the quality of life, lifestyle, health and economic impact on chiropractic patients presenting with back pain.”
What should we make of all this? I don’t know about you, but I fear the notion that chiropractic improves the quality of life of back pain patients is just another of these many bogus assumptions which chiropractors across the globe seem to promote, advertise and make a living from.
Five years ago to the day, Simon Singh and I published an article in The Daily Mail to promote our book TRICK OR TREATMENT… which was then about to be launched. We recently learnt that our short article prompted a “confidential” message by the BRITISH CHIROPRACTIC ASSOCIATION to all its members. “Confidential” needs to be put in inverted commas because it is readily available on the Internet. I find it fascinating and of sufficient public interest to reproduce it here in full. I have not altered a thing in the following text, except putting it in italics and putting the section where the BCA quote our text in bold for clarity.
CONFIDENTIAL FOR BCA MEMBERS ONLY
Information for BCA members regarding an article in the Daily Mail – April 8th 2008
A double page spread appeared in the edition of the Daily Mail April 8th 2008 on page 46 and 47 and titled ‘Alternative Medicine The Verdict’.
The article was written by Simon Singh and Edzard Ernst and is a publicity prelude to a book they have written called ‘Trick or Treatment? Alternative Medicine on Trial’, which will be published later this month.
The article covers Alexander Technique, Aromatherapy, Flower Remedy, Chiropractic, Hypnotherapy, Magnet Therapy and Osteopathy.
The coverage of Chiropractic follows a familiar pattern for E Ernst. The treatment is oversimplified in explanation, with a heavy emphasis on words like thrust, strong and aggressive. There is tacit acknowledgement that chiropractic works for back pain, but then there is a long section about caution regarding neck manipulation. The article concludes by advising people not to have their neck manipulated and not to allow children to be treated.
WHAT IS IT? Chiropractors use spinal manipulation to realign the spine to restore mobility. Initial examination often includes X-ray images or MRI scans.
Spinal manipulation can be a fairly aggressive technique, which pushes the spinal joint slightly beyond what it is ordinarily capable of achieving, using a technique called high-velocity, low-amplitude thrust – exerting a relatively strong force in order to move the joint at speed, but the extent of the motion needs to be limited to prevent damage to the joint and its surrounding structures.
Although spinal manipulation is often associated with a cracking sound, this is not a result of the bones crunching or a sign that bones are being put back; the noise is caused by the release and popping of gas bubbles, generated when the fluid in the joint space is put under severe stress.
Some chiropractors claim to treat everything from digestive disorders to ear infections, others will treat only back problems.
DOES IT WORK? There is no evidence to suggest that spinal manipulation is effective for anything but back pain and even then conventional approaches (such as regular exercise and ibuprofen) are just as likely to be effective and are cheaper.
Neck manipulation has been linked to neurological complications such as strokes – in 1998, a 20-year-old Canadian woman died after neck manipulation caused a blood clot which led to stroke. We would strongly recommend physiotherapy exercises and osteopathy ahead of chiropractic therapy because they are at least effective and much safer.
If you do decide to visit a chiropractor despite our concerns and warnings, we very strongly recommend you confirm your chiropractor won’t manipulate your neck. The dangers of chiropractic therapy to children are particularly worrying because a chiropractor would be manipulating an immature spine.
Daily Mail 2008 April 8th.
As we are aware that patients or potential patients of our members will be confronted with questions regarding this article, we have put together some comment and Q&As to assist you.
• Please consider this information as strictly confidential and for your use only.
• Only use this if a patient asks about these specific issues; there is nothing to be gained from releasing any information not asked for.
• Do not duplicate these patient notes and hand out direct to the patient or the media; these are designed for you to use when in direct conversation with a patient.
The BCA will be very carefully considering any questions or approaches we may receive from the press and will respond to them using specially briefed spokespeople. We would strongly advise our members not to speak directly to the press on any of the issues raised as a result of this coverage.
Please note that In the event of you receiving queries from the media, please refer these direct to BCA (0118 950 5950 – Anne Barlow or Sue Wakefield) or Publicasity (0207 632 2400 – Julie Doyle or Sara Bailey).
The following points should assist you in answering questions that patients may ask with regard to the safety and effectiveness of chiropractic care. Potential questions are detailed along with the desired ‘BCA response’:
o “The Daily Mail article seems to suggest chiropractic treatment is not that effective”
Nothing could be further from the truth. The authors have had to concede that chiropractic treatment works for back pain as there is overwhelming evidence to support this. The authors also contest that pain killers and exercises can do the job just as well. What they fail to mention is that research has shown that this might be the case for some patients, but the amount of time it may take to recover is a lot longer and the chance of re-occurrence of the problem is higher. This means that chiropractic treatment works, gets results more quickly and helps prevent re-occurrence of the problem. Chiropractic is the third largest healthcare profession in the world and in the UK is recognised and regulated by the UK Government.
o “The treatment is described as aggressive, can you explain?”
It is important to say that the authors of the article clearly have no direct experience of chiropractic treatment, nor have they bothered to properly research the training and techniques. Chiropractic treatment can take many forms, depending on the nature of the problem, the particular patient’s age and medical history and other factors. The training chiropractors receive is overseen by the government appointed regulator and the content of training is absolutely designed to ensure that an individual chiropractor understands exactly which treatment types are required in each individual patient scenario. Gentle technique, massage and exercise are just some of the techniques available in the chiropractor’s ‘toolkit’. It is a gross generalisation and a demonstration of lack of knowledge of chiropractic to characterise it the way it appeared in the article.
o “The article talked about ‘claims’ of success with other problems”
There is a large and undeniable body of evidence regarding the effectiveness of chiropractic treatment for musculoskeletal problems such as back pain. There is also growing evidence that chiropractic treatment can help many patients with other problems; persistent headaches for example. There is also anecdotal evidence and positive patient experience to show that other kinds of problems have been helped by chiropractic treatment. For many of these kinds of problems, the formal research is just beginning and a chiropractor would never propose their treatment as a substitute for other, ongoing treatments.
o “Am I at risk of having a stroke if I have a chiropractic treatment?”
What is important to understand is that any association between neck manipulation and stroke is extremely rare. Chiropractic is a very safe form of treatment.
Another important point to understand is that the treatments employed by chiropractors are statistically safer than many other conservative treatment options (such as ibuprofen and other pain killers with side effects such as gastric bleeding) for mechanical low back or neck pain conditions.
A research study in the UK, published just last year studied the neck manipulations received by nearly 20,000 chiropractic patients. NO SERIOUS ADVERSE SIDE EFFECTS WERE IDENTIFIED AT ALL. In another piece of research, published in February this year, stroke was found to be a very rare event and the risk associated with a visit to a chiropractor appeared to be no different from the risk of a stroke following a visit to a GP.
Other recent research shows that such an association with stroke may occur once in every 5.85 million adjustments.
To put this in context, a ‘significant risk’ for any therapeutic intervention (such as pain medication) is defined as 1 in 10,000.
Additional info: Stroke is a natural occurring phenomenon, and evidence dictates that a number of key risk factors increase the likelihood of an individual suffering a stroke. Smoking, high blood pressure, high cholesterol and family medical histories can all contribute; rarely does a stroke occur in isolation from these factors. Also, stroke symptoms can be similar to that of upper neck pains, stiffness or headaches, conditions for which patients may seek chiropractic treatment. BCA chiropractors are trained to recognise and diagnose these symptoms and advise appropriate mainstream medical care.
o “Can you tell if I am at risk from stroke?”
As a BCA chiropractor I am trained to identify risk factors and would not proceed with treatment if there was any doubt as to the patient’s suitability. Potential risks may come to light during the taking of a case history, which may include: smoking, high cholesterol, contraceptive pill, Blood clotting problems/blood thinning meds, heart problems, trauma to the head etc and on physical examination e.g. high blood pressure, severe osteoarthritis of the neck, history of rheumatoid arthritis
o “Do you ever tell patients if they are at risk?”
Yes, I would always discuss risks with patients and treatment will not proceed without informed consent.
o “Is it safe for my child to be treated by a chiropractor”
It is a shame that the article so generalises the treatment provided by a chiropractor, that it makes such outrageous claims. My training in anatomy, physiology and diagnosis means that I absolutely understand the demands and needs of spines from the newborn baby to the very elderly patient. The techniques and treatments I might use on a 25 year old are not the same as those I would employ on a 5 year old. I see a lot of children as patients at this clinic and am able to offer help with a variety of problems with the back, joints and muscles. I examine every patient very thoroughly, understand their medical history and discuss my findings with them and their parents before undertaking any treatment.
– Chiropractic is a mature profession and numerous studies clearly demonstrate that chiropractic treatment, including manipulative and spinal adjustment, is both safe and effective.
– Thousands of patients are treated by me and my fellow chiropractors every day in the UK. Chiropractic is a healthcare profession that is growing purely because our patients see the results and GPs refer patients to us because they know we get results!
This article is to promote a book and a controversial one at that. Certainly, in the case of the comments about chiropractic, there is much evidence and research that has formed part of guidelines developed by the Royal Society of General Practitioners, NICE and other NHS/Government agencies, has been conveniently ignored. The statements about chiropractic treatment and technique demonstrate that there has clearly been no research into the actual education that chiropractors in the UK receive – in my case a four year full-time degree course that meets stringent educational standards set down by the government appointed regulator.
Shortly after the article in The Daily Mail, our book was published and turned out to be much appreciated by critical thinkers across the globe — not, however, by chiropractors.
At the time, I did, of course, not know about the above “strictly confidential” message to BCA members, yet I strongly suspected that chiropractors would do everything in their power to dispute our central argument, namely that most of the therapeutic claims by chiropractors were not supported by sufficient evidence. I also knew that our evidence for it was rock solid; after all, I had researched the evidence for or against chiropractic in full depth and minute detail and published dozens of articles on the subject in the medical literature.
When, one and a half weeks after our piece in the Mail, Simon published his now famous Guardian comment stating that the BCA “happily promote bogus treatments”, he was sued for libel by the BCA. I think the above “strictly confidential” message already reveals the BCA’s determination and their conviction to be on firm ground. As it turned out, they were wrong. Not only did they lose their libel suit, but they also dragged chiropractic into a deep crisis.
The “strictly confidential” message is intriguing in several more ways – I will leave it to my readers to pick out some of the many gems hidden in this text. Personally, I find the most remarkable aspect that the BCA seems to attempt to silence its own members regarding the controversy about the value of their treatments. Instead they proscribe answers (should I say doctrines?) of highly debatable accuracy for them, almost as though chiropractors were unable to speak for themselves. To me, this smells of cult-like behaviour, and is by no means indicative of a mature profession – despite their affirmations to the contrary.
In 2010, I have reviewed the deaths which have been reported after chiropractic treatments. My article suggested that 26 fatalities had been published in the medical literature and many more might have remained unpublished. The alleged pathology usually was a vascular accident involving the dissection of a vertebral artery. Whenever I write about the risks of spinal manipulation, chiropractors say that I am irresponsible and alarmist. Yet I believe I am merely doing my duty in alerting health care professionals and the public to the possibility that this intervention is associated with harm and that caution is therefore recommended.
Fortunately, I am not alone, as a new report from China shows.This review summarised published cases of injuries associated with cervical manipulation in China, and to describe the risks and benefits of the therapy.
A total of 156 cases met the inclusion criteria. They included the following problems: syncope = 45 cases , mild spinal cord injury or compression = 34 cases, nerve root injury = 24 cases, ineffective treatment or symptom increased = 11 cases ; cervical spine fracture = 11 cases, dislocation or semiluxation = 6 cases, soft tissue injury = 3 cases, serious accident = 22 cases including paralysis, death and cerebrovascular accident. Manipulation including rotation was involved in 42.00%, 63 cases). 5 patients died.
The authors conclude that “it is imperative for practitioners to complete the patients’ management and assessment before manipulation. That the practitioners conduct a detailed physical examination and make a correct diagnosis would be a pivot method of avoiding accidents. Excluding contraindications and potential risks, standardizing evaluation criteria and practitioners’ qualification, increasing safety awareness and risk assessment and strengthening the monitoring of the accidents could decrease the incidence of accidents” (I do apologize for the authors’ poor English).
It is probable that someone will now calculate that the risk of harm is minute. Chinese traditional healers seem to use spinal manipulation fairly regularly, so the incidence of complications would be one in several millions.
Such calculations are frequently made by chiropractors in an attempt to define the incidence rates of risks associated with chiropractic in the West. They look convincing but, in fact, they are complete nonsense.
The reason is that under-reporting can be huge. Clinical trials of chiropractic often omit any mention of adverse effects (thus violating publication ethics) and, in our case-series, under-reporting was precisely 100% (none of the cases we discovered had been recorded anywhere). This means that these estimates are entirely worthless.
I sincerely hope that the risk turns out to be extremely low – but without a functioning reporting system for such events, we might as well read tea-leaves.
If I had a pint of beer for every time I have been accused of bias against chiropractic, I would rarely be sober. The thing is that I do like to report about decent research in this field and I am almost every day looking out for new articles which might be worth writing about – but they are like gold dust!
“Huuuuuuuuh, that just shows how very biased he is” I hear the chiro community shout. Well let’s put my hypothesis to the test. Here is a complete list of recent (2013)Medline-listed articles on chiropractic; no omission, no bias, just facts (for clarity, the Pubmed-link is listed first, then the title in bold followed by a short comment in italics):
Towards establishing an occupational threshold for cumulative shear force in the vertebral joint – An in vitro evaluation of a risk factor for spondylolytic fractures using porcine specimens.
This is an interesting study of the shear forces observed in porcine vertebral specimen during maneuvers which might resemble spinal manipulation in humans. The authors conclude that “Our investigation suggested that pars interarticularis damage may begin non-linearly accumulating with shear forces between 20% and 40% of failure tolerance (approximately 430 to 860N”
Development of an equation for calculating vertebral shear failure tolerance without destructive mechanical testing using iterative linear regression.
This is a mathematical modelling of the forces that might act on the spine during manipulation. The authors draw no conclusions.
Collaborative Care for Older Adults with low back pain by family medicine physicians and doctors of chiropractic (COCOA): study protocol for a randomized controlled trial.
This is merely the publication of a trial that is about to commence.
Military Report More Complementary and Alternative Medicine Use than Civilians.
This is a survey which suggests that ~45% of all military personnel use some form of alternative medicine.
Complementary and Alternative Medicine Use by Pediatric Specialty Outpatients
This is another survey; it concludes that ” that CAM use is high among pediatric specialty clinic outpatients”
Extending ICPC-2 PLUS terminology to develop a classification system specific for the study of chiropractic encounters
This is an article on chiropractic terminology which concludes that “existing ICPC-2 PLUS terminology could not fully represent chiropractic practice, adding terms specific to chiropractic enabled coding of a large number of chiropractic encounters at the desired level. Further, the new system attempted to record the diversity among chiropractic encounters while enabling generalisation for reporting where required. COAST is ongoing, and as such, any further encounters received from chiropractors will enable addition and refinement of ICPC-2 PLUS (Chiro)”.
US Spending On Complementary And Alternative Medicine During 2002-08 Plateaued, Suggesting Role In Reformed Health System
This is a study of the money spent on alternative medicine concluding as follows “Should some forms of complementary and alternative medicine-for example, chiropractic care for back pain-be proven more efficient than allopathic and specialty medicine, the inclusion of complementary and alternative medicine providers in new delivery systems such as accountable care organizations could help slow growth in national health care spending”
A Royal Chartered College joins Chiropractic & Manual Therapies.
This is a short comment on the fact that a chiro institution received a Royal Charter.
Exposure-adjusted incidence rates and severity of competition injuries in Australian amateur taekwondo athletes: a 2-year prospective study.
This is a study by chiros to determine the frequency of injuries in taekwondo athletes.
The first thing that strikes me is the paucity of articles; ok, we are talking of just january 2013 but by comparison most medical fields like neurology, rheumatology have produced hundreds of articles during this period and even the field of acupuncture research has generated about three times more.
The second and much more important point is that I fail to see much chiropractic research that is truly meaningful or tells us anything about what I consider the most urgent questions in this area, e.g. do chiropractic interventions work? are they safe?
My last point is equally critical. After reading the 9 papers, I have to honestly say that none of them impressed me in terms of its scientific rigor.
So, what does this tiny investigation suggest? Not a lot, I have to admit, but I think it supports the hypothesis that research into chiropractic is not very active, nor high quality, nor does it address the most urgent questions.
Musculoskeletal and rheumatic conditions, often just called “arthritis” by lay people, bring more patients to alternative practitioners than any other type of disease. It is therefore particularly important to know whether alternative medicines (AMs) demonstrably generate more good than harm for such patients. Most alternative practitioners, of course, firmly believe in what they are doing. But what does the reliable evidence show?
To find out, ‘Arthritis Research UK’ has sponsored a massive project lasting several years to review the literature and critically evaluate the trial data. They convened a panel of experts (I was one of them) to evaluate all the clinical trials that are available in 4 specific clinical areas. The results for those forms of AM that are to be taken by mouth or applied topically have been published some time ago, now the report, especially written for lay people, on those treatments that are practitioner-based has been published. It covers the following 25 modalities:
Chiropractic (spinal manipulation)
Kinesiology (applied kinesiology)
Magnet therapy (static magnets)
Osteopathy (spinal manipulation)
Qigong (internal qigong)
Our findings are somewhat disappointing: only very few treatments were shown to be effective.
In the case of rheumatoid arthritis, 24 trials were included with a total of 1,500 patients. The totality of this evidence failed to provide convincing evidence that any form of AM is effective for this particular condition.
For osteoarthritis, 53 trials with a total of ~6,000 patients were available. They showed reasonably sound evidence only for two treatments: Tai chi and acupuncture.
Fifty trials were included with a total of ~3,000 patients suffering from fibromyalgia. The results provided weak evidence for Tai chi and relaxation-therapies, as well as more conclusive evidence for acupuncture and massage therapy.
Low back pain had attracted more research than any of the other diseases: 75 trials with ~11,600 patients. The evidence for Alexander Technique, osteopathy and relaxation therapies was promising by not ultimately convincing, and reasonably good evidence in support of yoga and acupuncture was also found.
The majority of the experts felt that the therapies in question did not frequently cause harm, but there were two important exceptions: osteopathy and chiropractic. For both, the report noted the existence of frequent yet mild, as well as serious but rare adverse effects.
As virtually all osteopaths and chiropractors earn their living by treating patients with musculoskeletal problems, the report comes as an embarrassment for these two professions. In particular, our conclusions about chiropractic were quite clear:
There are serious doubts as to whether chiropractic works for the conditions considered here: the trial evidence suggests that it’s not effective in the treatment of fibromyalgia and there’s only little evidence that it’s effective in osteoarthritis or chronic low back pain. There’s currently no evidence for rheumatoid arthritis.
Our point that chiropractic is not demonstrably effective for chronic back pain deserves some further comment, I think. It seems to be in contradiction to the guideline by NICE, as chiropractors will surely be quick to point out. How can this be?
One explanation is that, since the NICE-guidelines were drawn up, new evidence has emerged which was not positive. The recent Cochrane review, for instance, concludes that spinal manipulation “is no more effective for acute low-back pain than inert interventions, sham SMT or as adjunct therapy”
Another explanation could be that the experts on the panel writing the NICE-guideline were less than impartial towards chiropractic and thus arrived at false-positive or over-optimistic conclusions.
Chiropractors might say that my presence on the ‘Arthritis Research’-panel suggests that we were biased against chiropractic. If anything, the opposite is true: firstly, I am not even aware of having a bias against chiropractic, and no chiropractor has ever demonstrated otherwise; all I ever aim at( in my scientific publications) is to produce fair, unbiased but critical assessments of the existing evidence. Secondly, I was only one of a total of 9 panel members. As the following list shows, the panel included three experts in AM, and most sceptics would probably categorise two of them (Lewith and MacPherson) as being clearly pro-AM:
Professor Michael Doherty – professor of rheumatology, University of Nottingham
Professor Edzard Ernst – emeritus professor of complementary medicine, Peninsula Medical School
Margaret Fisken – patient representative, Aberdeenshire
Dr Gareth Jones (project lead) – senior lecturer in epidemiology, University of Aberdeen
Professor George Lewith – professor of health research, University of Southampton
Dr Hugh MacPherson – senior research fellow in health sciences, University of York
Professor Gary Macfarlane (chair of committee) – professor of epidemiology, University of Aberdeen
Professor Julius Sim – professor of health care research, Keele University
Jane Tadman – representative from Arthritis Research UK, Chesterfield
What can we conclude from all that? I think it is safe to say that the evidence for practitioner-based AMs as a treatment of the 4 named conditions is disappointing. In particular, chiropractic is not a demonstrably effective therapy for any of them. This, of course begs the question, for what condition is chiropractic proven to work! I am not aware of any, are you?
The question whether spinal manipulation is an effective treatment for infant colic has attracted much attention in recent years. The main reason for this is, of course, that a few years ago Simon Singh had disclosed in a comment that the British Chiropractic Association (BCA) was promoting chiropractic treatment for this and several other childhood condition on their website. Simon famously wrote “they (the BCA) happily promote bogus treatments” and was subsequently sued for libel by the BCA. Eventually, the BCA lost the libel action as well as lots of money, and the entire chiropractic profession ended up with enough egg on their faces to cook omelets for all their patients.
At the time, the BCA had taken advice from several medical and legal experts; one of their medical advisers, I was told, was Prof George Lewith. Intriguingly, he and several others have just published a Cochrane review of manipulative therapies for infant colic. Here are the unabbreviated conclusions from their article:
“The studies included in this meta-analysis were generally small and methodologically prone to bias, which makes it impossible to arrive at a definitive conclusion about the effectiveness of manipulative therapies for infantile colic. The majority of the included trials appeared to indicate that the parents of infants receiving manipulative therapies reported fewer hours crying per day than parents whose infants did not, based on contemporaneous crying diaries, and this difference was statistically significant. The trials also indicate that a greater proportion of those parents reported improvements that were clinically significant. However, most studies had a high risk of performance bias due to the fact that the assessors (parents) were not blind to who had received the intervention. When combining only those trials with a low risk of such performance bias, the results did not reach statistical significance. Further research is required where those assessing the treatment outcomes do not know whether or not the infant has received a manipulative therapy. There are inadequate data to reach any definitive conclusions about the safety of these interventions”
Cochrane reviews also carry a “plain language” summary which might be easier to understand for lay people. And here are the conclusions from this section of the review:
The studies involved too few participants and were of insufficient quality to draw confident conclusions about the usefulness and safety of manipulative therapies. Although five of the six trials suggested crying is reduced by treatment with manipulative therapies, there was no evidence of manipulative therapies improving infant colic when we only included studies where the parents did not know if their child had received the treatment or not. No adverse effects were found, but they were only evaluated in one of the six studies.
If we read it carefully, this article seems to confirm that there is no reliable evidence to suggest that manipulative therapies are effective for infant colic. In the analyses, the positive effect disappears, if the parents are properly blinded; thus it is due to expectation or placebo. The studies that seem to show a positive effect are false positive, and spinal manipulation is, in fact, not effective.
The analyses disclose another intriguing aspect: most trials failed to mention adverse effects. This confirms the findings of our own investigation and amounts to a remarkable breach of publication ethics (nobody seems to be astonished by this fact; is it normal that chiropractic researchers ignore generally accepted rules of ethics?). It also reflects badly on the ability of the investigators of the primary studies to be objective. They seem to aim at demonstrating only the positive effects of their intervention; science is, however, not about confirming the researchers’ prejudices, it is about testing hypotheses.
The most remarkable thing about the new Cochrane review is, I think, the in-congruence of the actual results and the authors’ conclusion. To a critical observer, the former are clearly negative but the latter sound almost positive. I think this begs the question about the possibility of reviewer bias.
We have recently discussed on this blog whether reviews by one single author are necessarily biased. The new Cochrane review has 6 authors, and it seems to me that its conclusions are considerably more biased than my single-author review of chiropractic spinal manipulation for infant colic; in 2009, I concluded simply that “the claim [of effectiveness] is not based on convincing data from rigorous clinical trials”.
Which of the two conclusions describe the facts more helpfully and more accurately?
I think, I rest my case.
Even though I have not yet posted a single article on this subject, it already proved to be a most controversial subject in the comments section. A new analysis of the evidence has just been published, and, in view of the news just out of a Royal Charter for the UK College of Chiropractors, it is time to dedicate some real attention to this important issue.
The analysis comes in the form of a systematic review authored by an international team of chiropractors (we should not fear therefore that the authors have an “anti-chiro bias”). Their declared aim was “to determine whether conclusive evidence of a strong association [between neck manipulation and vascular accidents] exists”. The authors make it clear that they only considered case-control studies and omitted all other articles.
They found 4 such publications all of which had methodological limitations. Two studies were of acceptable quality, and one of these studies seemed to show an association between neck manipulation and stroke, while the other one did not. The authors’ conclusion is ambivalent: “Conclusive evidence is lacking for a strong association between neck manipulation and stroke, but it is also lacking for no association”.
The 4 case-control studies, their strength and weaknesses are, of course, well-known and have been discussed several times before. It was also known that the totality of these data fail to provide a clear picture. I would therefore argue that, in such a situation, we need to include further evidence in an attempt to advance the discussion.
Generally speaking, whenever we assess therapeutic safety, we must not ignore case-reports. One might be next to meaningless but collectively they can provide strong indicators of risk. In drug research, for instance, they send invaluable signals about potential problems and many drugs have been withdrawn from the market purely on the basis of case-reports. If we include case-reports in an analysis of the risks of neck manipulations, the evidence generated by the existing case-control studies appears in a very different light. There are virtually hundreds of cases where neck manipulations have seriously injured patients, and many have suffered permanent neurological deficits or worse. Whenever causation is validated by experts who are not chiropractors and thus not burdened with a professional bias, investigators find that most of the criteria for a causal relationship are fulfilled.
While the omission of case-reports in the new review is regrettable, I find many of the staements of the authors helpful and commendable, particularly considering that they are chiropractors. They seem to be aware that, when there is genuine uncertainty, we ought to err on the safe side [the precautionary principle]. Crucially, they comment on the practical implications of our existing knowledge: “Considering this uncertainty, informed consent is warranted for cervical spinal manipulative therapy that advises patients of a possible increase in the risk of a rare form of stroke…” A little later, in their discussion they write: “As the possibility of an association between cervical spinal manipulative therapy and vascular accidents cannot be ruled out, practitioners of cervical spinal manipulative therapy are obliged to take all reasonable steps that aim to minimise the potential risk of stroke. There is evidence that cervical rotation places greater stresses on vertebral arteries than other movements such as lateral flexion, and so it would seem wise to avoid techniques that involve full rotation of the head.”
At this point it is, I think, important to note that UK chiropractors tend not to obtain informed consent from their patients. This is, of course, a grave breach of medical ethics. It becomes even graver, when we consider that the GCC seems to do nothing about it, even though it has been known for many years.
Is this profession really worthy of a Royal Charter? This and the other question raised here require some serious consideration and discussion which, no doubt, will follow this short post.