A recently published study by Danish researchers aimed at comparing the effectiveness of a patient education (PEP) programme with or without the added effect of chiropractic manual therapy (MT) to a minimal control intervention (MCI). Its results seem to indicate that chiropractic MT is effective. Is this the result chiropractors have been waiting for?

To answer this question, we need to look at the trial and its methodology in more detail.

A total of 118 patients with clinical and radiographic unilateral hip osteoarthritis (OA) were randomized into one of three groups: PEP, PEP+ MT or MCI. The PEP was taught by a physiotherapist in 5 sessions. The MT was delivered by a chiropractor in 12 sessions, and the MCI included a home stretching programme. The primary outcome measure was the self-reported pain severity on an 11-box numeric rating scale immediately following the 6-week intervention period. Patients were subsequently followed for one year.

The primary analyses included 111 patients. In the PEP+MT group, a statistically and clinically significant reduction in pain severity of 1.9 points was noted compared to the MCI of 1.90. The number needed to treat for PEP+MT was 3. No difference was found between the PEP and the MCI groups. At 12 months, the difference favouring PEP+MT was maintained.

The authors conclude that for primary care patients with osteoarthritis of the hip, a combined intervention of manual therapy and patient education was more effective than a minimal control intervention. Patient education alone was not superior to the minimal control intervention.

This is an interesting, pragmatic trial with a result suggesting that chiropractic MT in combination with PEP is effective in reducing the pain of hip OA. One could easily argue about the small sample size, the need for independent replication etc. However, my main concern is the fact that the findings can be interpreted in not just one but in at least two very different ways.

The obvious explanation would be that chiropractic MT is effective. I am sure that chiropractors would be delighted with this conclusion. But how sure can we be that it would reflect the truth?

I think an alternative explanation is just as (possibly more) plausible: the added time, attention and encouragement provided by the chiropractor (who must have been aware what was at stake and hence highly motivated) was the effective element in the MT-intervention, while the MT per se made little or no difference. The PEP+MT group had no less than 12 sessions with the chiropractor. We can assume that this additional care, compassion, empathy, time, encouragement etc. was a crucial factor in making these patients feel better and in convincing them to adhere more closely to the instructions of the PEP. I speculate that these factors were more important than the actual MT itself in determining the outcome.

In my view, such critical considerations regarding the trial methodology are much more than an exercise in splitting hair. They are important in at least two ways.

Firstly, they remind us that clinical trials, whenever possible, should be designed such that they allow only one interpretation of their results. This can sometimes be a problem with pragmatic trials of this nature. It would be wise, I think, to conduct pragmatic trials only of interventions which have previously been proven to work.  To the best of my knowledge, chiropractic MT as a treatment for hip OA does not belong to this category.

Secondly, it seems crucial to be aware of such methodological issues and to consider them carefully before research findings are translated into clinical practice. If not, we might end up with  therapeutic decisions (or guidelines) which are quite simply not warranted.

I would not be in the least surprised, if chiropractic interest groups were to use the current findings for promoting chiropractic in hip-OA. But what, if the MT per se was ineffective, while the additional care, compassion and encouragement was? In this case, we would not need to recruit (and pay for) chiropractors and put up with the considerable risks chiropractic treatments can entail; we would merely need to modify the PE programme such that patients are better motivated to adhere to it.

As it stands, the new study does not tell us much that is of any practical use. In my view, it is a pragmatic trial which cannot readily be translated into evidence-based practice. It might get interpreted as good news for chiropractic but, in fact, it is not.

23 Responses to Is this the study chiropractors have been waiting for?

  • Another case of A+B > A.
    Was any attempt made to assess the adherence to PEP within the 2 groups?
    Also I doubt whether a physiotherapy treatment would omit some sort of manipulation or other intervention in addition to PEP, so it’s hard to see what real world patient choice this models.

    • As a chiropractor, all the patients I have who have been through standard physio via a musculo-skeletal pathway receive NO hands on therapy at all. This study represents a very real-world model which is probably why they chose it for comparison.

      • It is interesting that they reported this to you. Is their reason for coming to you that the physio asked them to do stuff for themselves, but they wanted to have stuff done to them?

  • I’m interested to read what you’re saying but can’t quite follow the argument fully, and one point in particular, where you say: “It would be wise, I think, to conduct pragmatic trials only of interventions which have previously been proven to work.” I would have thought that the whole point of a pragmatic trial was to establish whether or not a treatment did work?

    • no, a pragmatic trial tests whether a treatment might be useful in practice under real life conditions. an efficacy study tests whether it can work under ideal conditions.

  • Without some kind of blinding or independent clinical evaluation of results, the whole seems pointless. Not sure how you would “blind” this kind of thing, but perhaps you could have chiro and sham chiro for comparison (amusing idea, since chiro IS a sham already).

    • amusing, perhaps!
      but sham-controlled chiro-trials do exist.

      • Glad to hear it. I’d love to read one as I cannot imagine how you fake something fake. It’s tooth fairy science at its best; rather like substituting water for homeopathic remedies!

    • If as you say, all Chiropractors are shams, you therefore must by definition include Osteopaths and Manip-Physiotherapists as shams too.

      Additionally you would have to include manipulative-GPs and Orthopaedic surgeons who use manipulation in their treatments too.

      …Or were you intending to include these groups as shams too?

      PS: Phyios did not manipulate until the early 80s. Up until that time they openly castigated Osteopaths and Chiropractors.

  • “the added time, attention and encouragement provided by the chiropractor (who must have been aware what was at stake and hence highly motivated) was the effective element in the MT-intervention, while the MT per se made little or no difference.”

    ALL the therapists (and patients) are highly motivated in this study for good results, as is true in clinical practice.
    If you’re concern reference this study is the non-specific-therapeutic-benefits of treatment, then we are back to the familiar restrain of how-do-we-remove-placebo-from-research.

    The “additional care, compassion, empathy, time, encouragement” is an intrinsic part of patients receiving care. Would you feel happier if the group that received Manual therapy (MT) was simply renamed Chiropractic care? You can’t have Chiropractic without the care, compassion, time, empathy and encouragement, so in practice its impossible to divide from the therapy itself.

    • in clinical trials, we want to find out which component of the treatment is effective. a doctor prescribing andrug will also have time empathy, compassion etc. so the patient might get better because of the drug or the non-specific effects of the encounter. are you saying that it is not important to determine which element caused which effect?

      • Yes Edzard, we do need to TRY and determine which part of the treatment is beneficial, but this is always going to be the problem with RCT using real patients and real clinicians.

        The simplest answer in my view is to make sure that ALL clinicians are highly motivated to see an improvement in their patients during their respective groups. That way we compare like for like, rather than dismissing a study because some of the subjects received care from clinicians who actually care…

  • That’s most interesting, thanks, and I’ve just been looking up the details of the difference between the two types of trial and trying to work out the advantages and disadvantages for different types of testing. My initial thought – coming to the subject totally fresh and thinking about medicine in general rather than any particular aspect of it – is that if I was carrying out a test I would start with pragmatic trials and then gradually hone them down to try to identify the specific elements that were having the effect and then go to the explanatory trials. But there’s probably a good reason why in practice it’s the other way round. I really have to read more about this.

  • I would have thought that the logical first question would be: Does it work? If the answer is no, then I need not pursue the matter. If the answer is yes, my second question would be: how does it work? For example, in bird migration, there was a question as to whether magnetism was involved, so to tackle the question, a researcher attached magnets to some pigeons and non-magnets to others to see if they could still home, and he found that the ones with the magnets couldn’t manage to find their way. In the light of the information that there was something there to be investigated, researchers then went to the second stage, to try to work out what the mechanism might be; and that question indeed continues to be a challenge. So the first stage is to ask: what happens in practice? And the second stage is to ask: can we develop a hypothesis to account for the observations?

    • we know from hundreds of surveys etc. what happens in practice.
      the 1st question for alt meds which are in popular use already must be, does it work better than a placebo?
      if yes, we should ask what the mechanism is.
      this is a little different from pharmaceutical research; mostly because a new drug is not already in popular use.

  • Yes, thanks, that is what I was asking, that I would have thought the sequence should be first, does it work, and second – if it does – what is the mechanism?

    I’m not clear why a placebo is used as the baseline, since the placebo effect is something that exists in its own right. When a possible treatment or therapy is assessed, is it also compared again doing nothing? In other words, are there three different options that are assessed: (1) the treatment or therapy; (2) a placebo involving the form but not the content of the treatment; (3) no action?

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