Spinal Manipulation Therapy (SMT) is the primary treatment used by most chiropractors and osteopaths as well as being used by some physiotherapists. This study set out to compare Spinal Manipulation Therapy (SMT) with recommended therapies, non-recommended therapies, sham SMT and SMT as adjuvant therapy. It concluded that SMT showed similar benefits to “recommended interventions”. When it was published it was met with trumpet fanfares by a number of chiropractic organisations, as well as others, and claimed as providing strong justification for their treatments. In actual fact it does not do this so let’s explore further.
Summary of conclusions:
1. There are currently no really effective treatments for low back pain.
2. At best, SMT results in a modest average clinical effect. It has also not been shown to be more effective than sham SMT.
3. It’s not currently possible to know whether SMT is safe.
4. It is not currently clear whether SMT is cost effective or not.
5. Taking into account the limited clinical effectiveness and unclear position on safety and cost effectiveness it doesn’t seem to make sense to recommend SMT as a first-line treatment.
Back pain is a widespread problem and SMT is currently listed as a second-line or adjunctive treatment in a number of national guidelines, such as the UK NICE Guidelines as well as the Lancet low back pain guidelines from last year. It’s not recommended as a first-line treatment because current evidence shows it is not sufficiently effective when used alone.
The study and its conclusions
The study was a systematic review and meta-analysis that compared SMT with recommended therapies, non-recommended therapies, sham SMT and SMT as adjuvant therapy. It identified recommended and non-recommended interventions based on guidelines from US, UK and The Netherlands. It’s not clear why these particular guidelines were picked. The Lancet series used a similar set but with Denmark in place of The Netherlands. Perhaps the inclusion of the guideline from The Netherlands is due to the lead author being based there? Whilst it’s understandable that someone will be more familiar and comfortable with guidelines from the country in which they live and work this does introduce a degree of bias into the results and it would be good to see that acknowledged in the paper.
The study concluded that SMT showed similar benefits to “recommended interventions”. It also concluded that SMT vs “non-recommended interventions” shows a statistically but not clinically significant benefit for pain but a statistically and clinically significant benefit for “back specific functional status”. There have been some criticisms, but more on that shortly.
A number of chiropractic organisations, as well as others, latched onto this study and claimed it is strong justification for their treatments. Take for instance, this tweet from the British Chiropractic Association:
It suggests that SMT, the treatment most favoured by most chiropractors, should be considered a first-line treatment for chronic low back pain.
There is also this from the Chiropractic Research Council which includes the comment “supersedes other reviews and publications e.g The Lancet Series which only recommended SMT as a second line treatment option. Groundbreaking stuff!”
As I’ll explain shortly, this review is not particularly “groundbreaking” and the justification for SMT being a first-line treatment is nowhere near as strong as these comments would suggest.
Criticisms of the paper
A thorough and clear critique of the paper was submitted by Mary O’Keeffe and Neil O’Connell. This highlighted a number of issues, including:
- SMT was not shown to be better than sham SMT. As this is the only reliable way of assessing efficacy of SMT, it suggests that SMT is not effective as a treatment.
- The choice of “recommended” and “non-recommended” therapies was strange and does not align with guidelines. For instance, treatment with paracetamol (which is not recommended by clinical guidelines) was included as “recommended” therapy.
- The authors do not seem to interpret their results in line with their own thresholds for determining clinical effectiveness.
The authors submitted a response in which they stand by their original conclusions. They say that SMT cannot be adequately blinded and that therefore trials that compare with other treatments are more valuable than those comparing SMT to sham. In response to point 2 above about choice of “recommended” and “non-recommended” therapies, they say they have undertaken additional analysis taking account of this point and have still arrived at similar results. As far as I can tell, they haven’t responded to the point about thresholds for clinical effectiveness.
Neil O’Connell has sent some further replies on twitter about comparison with sham and the fact that we might see the same minimal benefit for an ineffective treatment:
It seems likely that this discussion will continue. Hopefully the authors will continue to engage as it’s good to have a healthy debate on complex issues like this. What’s clear is that SMT has not been shown to be particularly effective for low back pain and this new study doesn’t change that.
Safety of SMT
The paper says “About half of the studies examined adverse events (table 2). In most of these studies it was unclear how and whether adverse events were registered systematically; therefore, these data might be unreliable and not accurate for incidence.” In other words: due to a lack of systematic reporting of adverse events, it’s impossible to adequately assess the safety of SMT. The paper does go on to say “clinicians should ensure that patients are fully informed of potential risks before treatment”. This is good advice but I wonder how much this actually happens in practice? Do the main people who carry out SMT (osteopaths, chiropractors and some physiotherapists) ensure that their patients are fully informed of potential risks before they start treatment? Or do they just go ahead and start treatment without doing this?
The paper states “it remains to be determined whether SMT is a cost effective option for the treatment of chronic low back pain.” As more research is needed to assess the cost effectiveness of SMT it would make sense to conduct this research before deciding whether to recommend it as a first-line treatment. If it turns out to be significantly more expensive than other similarly effective treatments then it would not make sense to recommend it as a first-line treatment.
Placing these results in the context of other research
In the section of the paper “Comparison with other studies” it is stated that “our results are consistent with other recently published high quality systematic reviews and guidelines that recommend SMT”. I disagree that it is consistent with guidelines, e.g. from NICE, because they have SMT as a second-line treatment option whereas this paper suggests it is as good as currently recommended first-line treatments.
The paper says “Given the considerable data available, we can now calculate within reasonable certainty the effect of SMT in this setting as well as the impact of a future, methodologically well conducted trial (as determined by the prediction intervals).” In other words, don’t keep doing more similar research in this area because it isn’t going to add anything. This is good advice and is something that researchers should conclude much more often than currently happens. Far too often a study that doesn’t show effectiveness suggests that “more research is needed”. This is a waste of time and money as there is no point in continuing to carry out research when it isn’t going to add anything new.
Overall, this is a decent piece of research and shows fairly similar results to other previous research. It concludes “The evidence suggests that SMT results in a modest, average clinical effect at best”. What’s most strange is not the paper itself but the hype that has surrounded it. There were many “trumpet fanfares” from chiropractic organisations suggesting that this vindicates their treatments and should be used to promote them. It doesn’t actually do this. It shows that SMT isn’t a particularly effective treatment, that it’s not possible to adequately assess its safety and it is not known whether it’s cost effective or not. This is hardly a justification for shouting from the rooftops about how good it is.
What this study does do is add to the body of evidence that indicates that, unfortunately, there remains no good treatment for low back pain. This presents an issue for the many people who suffer with low back pain as there are no really effective treatments. When presented with a number of treatments that are not particularly effective, what is someone with back pain supposed to do? There is no easy answer. However, exercise is known to provide general health benefits and the NHS provides activity guidelines. The importance of these general health benefits should not be understated and is something that SMT cannot provide. In addition, the NICE guidelines recommend exercise as the first-line treatment as well as highlighting the importance of continuing with normal activities as far as possible (self-management). These approaches have the advantage of empowering the patient whereas SMT is a purely passive treatment that does not encourage self-management. I can understand the temptation for someone with back pain to want to go and “get fixed” by seeing a chiropractor, osteopath or physiotherapist who uses SMT. Unfortunately, the evidence indicates that it is not particularly effective and it’s not clear how safe it is. Bearing in mind that it doesn’t provide other general health benefits or empower the patient and is not currently considered a first-line treatment by national guidelines it should probably remain a second-line or adjunctive treatment.