MD, PhD, FMedSci, FSB, FRCP, FRCPEd

Swiss chiropractors have just published a clinical trial to investigate outcomes of patients with radiculopathy due to cervical disk herniation (CDH). All patients had neck pain and dermatomal arm pain; sensory, motor, or reflex changes corresponding to the involved nerve root and at least one positive orthopaedic test for cervical radiculopathy were included. CDH was confirmed by magnetic resonance imaging. All patients received regular neck manipulations.

Baseline data included two pain numeric rating scales (NRSs), for neck and arm, and the Neck Disability Index (NDI). At two, four and twelve weeks after the initial consultation, patients were contacted by telephone, and the data for NDI, NRSs, and patient’s global impression of change were collected. High-velocity, low-amplitude thrusts were administered by experienced chiropractors. The proportion of patients reporting to feel “better” or “much better” on the patient’s global impression of change scale was calculated. Pre-treatment and post-treatment NRSs and NDIs were analysed.

Fifty patients were included. At two weeks, 55.3% were “improved,” 68.9% at four and 85.7% at twelve weeks. Statistically significant decreases in neck pain, arm pain, and NDI scores were noted at 1 and 3 months compared with baseline scores. 76.2% of all sub-acute/chronic patients were improved at 3 months.

The authors concluded that most patients in this study, including sub-acute/chronic patients, with symptomatic magnetic resonance imaging-confirmed CDH treated with spinal manipulative therapy, reported significant improvement with no adverse events.

In the presence of disc herniation, chiropractic manipulations have been described to cause serious complications. Some experts therefore believe that CDH is a contra-indication for spinal manipulation. The authors of this study imply, however, that it is not – on the contrary, they think it is an effective intervention for CDH.

One does not need to be a sceptic to notice that the basis for this assumption is less than solid. The study had no control group. This means that the observed effect could have been due to:

a placebo response,

the regression towards the mean,

the natural history of the condition,

concomitant treatments,

social desirability,

or other factors which have nothing to do with the chiropractic intervention per se.

And what about the interesting finding that no adverse-effects were noted? Does that mean that the treatment is safe? Sorry, but it most certainly does not! In order to generate reliable results about possibly rare complications, the study would have needed to include not 50 but well over 50 000 patients.

So what does the study really tell us? I have pondered over this question for some time and arrived at the following answer: NOTHING!

Is that a bit harsh? Well, perhaps yes. And I will revise my verdict slightly: the study does tell us something, after all – chiropractors tend to confuse research with the promotion of very doubtful concepts at the expense of their patients. I think, there is a name for this phenomenon: PSEUDO-SCIENCE.

8 Responses to The promotion of unsubstantiated claims under the guise of ‘research’

  • The methodology was awful as well. “Improved”, “impression of change”, patients reporting to “feel better”, etc.

    They call this science?

  • Professor Ernst’s post brings to mind section 146 (p.55) of the Statement of Claim of Sandra Nette, a Canadian tetraplegic chiropractic victim:

    Quote:
    “Incredibly, and, acting in bad faith, the College [Alberta College and Association of Chiropractors] attacked the new and surprisingly high number of vascular accidents associated with chiropractic services that were published medical literature and reported in the media by demanding a level of evidence it has never demanded of itself. It maintained that the causal link between strokes and chiropractic adjustment remained unproven.”

    Link: http://www.casewatch.org/mal/nette/claim.pdf

    In other words, many chiropractors – and their regulators – seem to find it acceptable to rely on anecdotal or weak evidence where it supports chiropractic treatment, but where similar, or more robust evidence suggests that serious complications (e.g. stroke) can result from chiropractic treatment, they are quick to dismiss it.

    No prizes for guessing why.

  • NOTHING? How such a study tells us nothing? This is not anecdotal evidence.

    I agree that a control group would make whatever study – MORE reliable. But nothing?????

    I have said before this is not a rational stance. Rational minds want to investigate whatever method SEEMS to have positive outcomes to validate or to INVALIDATE it.

    I would agree that this in NOT a proof of anything – but the evidence is quite strong- unless you have serious doubts about the sincerity of the people who conducted the study.

    Therefore, Your objection seems totally unfounded in terms of logic.

    • Thus spake George above:

      I agree that a control group would make whatever study – MORE reliable. But nothing?????

      Yes, nothing. The function of a control group is not to make the study more reliable; it is not a matter of scale or degree. Without a control, the testing of the hypothesis is incomplete, and the data therefrom, poor, unworthy of being used to draw any conclusion.

      I have said before this is not a rational stance. Rational minds want to investigate whatever method SEEMS to have positive outcomes to validate or to INVALIDATE it.

      Your grip on the principle of scientific experimentation seems quite tenuous. The scientific method is not a matter of beliefs and suppositions. A hypothesis was proposed, and it would not have been difficult to test the probability of the null hypothesis (i.e. chiropractic does fuck-all for CDH) with a properly designed and executed study. Which is precisely what did not happen in the case Prof. Ernst cited.

      I would agree that this in NOT a proof of anything – but the evidence is quite strong

      So… This is not a proof, but this is “evidence”?! Clearly, the word “evidence” does not mean what you think it means.

    • NOTHING? How such a study tells us nothing?

      Because without a control group there is no way of telling what would have happened without treatment.

      If you were to try to measure how tall I am from the position of my head, you might be tempted to claim that I am the tallest person in the world, because my head is currently about 300 feet above sea level (I’m not actually 300 feet tall; I just happen not to be standing by the sea). To measure how tall I am, it is necessary to know the position of my feet as well as the position of my head; without you also knowing the position my feet, the position of my head can tell you nothing about how tall I am.

      A study without a control group is like trying to tell how tall I am by just measuring the position of my head. The control group in a controlled trial is the equivalent of also measuring the position of my feet.

  • The study had no control group. This means that the observed effect could have been due to:
    a placebo response,
    the regression towards the mean,
    the natural history of the condition,
    concomitant treatments,
    social desirability,
    or other factors which have nothing to do with the chiropractic intervention per se.

    THIS. A million times, this. Kudos to Prof. Ernst for articulating the questions that pseudoscience aficionados fail, ad nauseam, to answer regarding their ‘experiments’. It is very important to remember these alternate hypotheses when attempting to explain the observed outcomes. Presence of the control group allows for proper analysis.

  • “Evidence, broadly construed, is anything presented in support of an assertion. This support may be strong or weak. The strongest type of evidence is that which provides direct proof of the truth of an assertion.”

    wiki says (and of course the second part is not correct — but one has to know some pure mathematics to understand why. )

    What they presented is evidence – according to this definition.

    However, the authors of the study did not claim they arrived to any definite conclusions—– as you say.

    They observed some good evidence – which might be due to other factors – as Ernst said – no one knows —–Is this enough to make researchers to investigate more given that you trust the sincerity and accuracy of their observation ?

    Rational minds would say yes – many times there is scientific research even in the presence of strong anecdotal evidence . Irrational minds say no.

  • Or more specifically —–“In scientific research evidence is accumulated through observations of phenomena that occur in the natural world, or which are created as experiments in a laboratory or other controlled conditions. Scientific evidence usually goes towards supporting or rejecting a hypothesis.”

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