Some of the pseudoscientific “alternative medicine” modalities we deal with are easy to summarize: homeopathy is 100% nonsense – nothing but water; acupuncture (if you define it as placing needles in specific acupuncture points) has no measurable effect beyond placebo, and therapeutic touch and other forms of energy healing are nothing but magical thinking. But when people ask me, “What do you think about chiropractic?” there is no one-liner. This is partly because “chiropractic” is not a monolithic profession; it is a many-headed beast. It is a mixture of legitimate interventions and pure pseudoscience in widely varying proportions. But also, chiropractors tend not to be self-reflective as a profession, and are shy about outside scrutiny.

But the internet contains a wealth of information and is increasingly useful as a tool to survey practices and claims. Edzard Ernst has recently published a survey of English-speaking chiropractic websites and found some very informative results. Ernst is a professor of complementary and alternative medicine and has become the Energizer Bunny of holding CAM up to the light of rigorous science.

The question is this – since many chiropractors mix evidence-based and non evidence-based practices, what can we say about the percentage of chiropractors who are basically evidence-based vs pseudoscientific? Are most chiropractors mostly scientific, or are most chiropractors peddling pseudoscience with just a patina of legitimacy?

The legitimate treatments chiropractors use is manipulation for lower back strain, for which there is some evidence of efficacy. Although there is no apparent advantage of any technique that is uniquely chiropractic – so physical therapists, sports medicine specialists, and physiatrists also use similar manipulative techniques. At their best, chiropractors are glorified physical therapists or sports medicine specialists. I am not aware of anything new or unique that they bring to the table, but some have developed a knowledge and skill base to function in this capacity.

But most chiropractors do not simply sell themselves or limit their interventions to physical medicine. They also include (again, to varying degrees) a variety of magical and pseudoscientific interventions, including the misuse of manipulative therapy. This includes high cervical manipulation for headaches and other conditions (an intervention that also carries a stroke risk), applied kinesiology, iridology, homeopathy (chiropractors are the most common prescribers of homeopathy in the US, although naturopaths are on the rise), and spinal manipulation for asthma, childhood ailments, and other conditions.

Now, really for the first time as far as I am aware, Ernst has provided at least some information about the percentage of chiropractors who engage in dubious treatments. He found:

Results: We found evidence that 190 (95%) chiropractor websites made unsubstantiated claims regarding at least one of the conditions. When colic and infant colic data were collapsed into one heading, there was evidence that 76 (38%) chiropractor websites made unsubstantiated claims about all the conditions not supported by sound evidence. 56 (28%) websites and 4 of the 9 (44%) associations made claims about lower back pain, whereas 179 (90%) websites and all 9 associations made unsubstantiated claims about headache/migraine. Unsubstantiated claims were made about asthma, ear infection/earache/otitis media, neck pain, whiplash in at least half of all chiropractor websites. Conclusions: The majority of chiropractors and their associations in the English-speaking world seem to make therapeutic claims that are not supported by sound evidence, whilst only 28% of chiropractor websites promote lower back pain, which is supported by some evidence. We suggest the ubiquity of the unsubstantiated claims constitutes an ethical and public health issue.

As a caveat, when chiropractors advertise themselves they may be focusing on the more dubious claims because they think that will attract clients. But it is reasonable to presume that what chiropractors advertise reflects what they actually do. This study suggests that 95% of chiropractors feature dubious treatments in their practice, and that more than half made unsubstantiated claims about many treatments, suggesting this forms a major part of their practice. This study strongly contradicts those who claim that chiropractors are mostly evidence-based but a few bad apples dabble in nonsense. The reverse is true – dubious treatments appear to be the mainstay of their practice, and a very few (5%) stick to evidence-based treatments.

2010 is the 100th anniversary of the Flexner Report – essentially an expose on poor-scientific regulation of medical practices that led to a scientific revolution in mainstream medicine. Chiropractic is in major need of its own Flexner Report (an Ernst Report?). In my opinion they need to clean house if they want to become respected members of the evidence-based mainstream medical community. They are trying to achieve this through legislation, lobbying, and advertising rather than genuine quality control, and that is a shame. As Ernst writes – their failure to do so constitutes an ethical and public health issue.