Anonymous Criticism - Defending Ernst

Image via WikipediaAs with most bloggers who allow it I have received a variety of comments on my last blog, The self-importance of being Ernst.  Generally it is my policy not to allow anonymous comments.  Since I have the courage to identify myself in the blog I think anyone wanting to comment should do the same.  Maybe that's my self-importance or it is my belief that one should have the courage of ones convictions. 

Someone submitted a few comments in defense of Ernst to my blog and given that the email address is their web site and that their web site, which is just a tirade about various CAM methods, does not allow any commentary moderated or not from their readers I choose not to provide him/her with the links, i.e. advertising.  However, I won't hide behind my ability to block a comment and will paste each of the comments and I'll reply.  If my anonymous critic comes out from behind the curtain I might then publish as-is the words of this Wizard of Oz :)

Criticism 1

I noted in my previous blog posting that it was...unusual for Ernst to have a copy of Long's pre-submitted testimony, which was rejected by the CT Board of Chiropractic Examiners.  My anonymous critic says:

If you read the ‘Methods’ section of Professor Ernst’s original paper he said that “several experts were also contacted for further data”. Perhaps that is how he managed to see Preston Long’s document.

Well that would be reasonable except that, Long doesn't fit any one's definition as an expert.Secondly one needs to keep in mind that Ernst was conducting a "systematic review".  In a systematic review it is not uncommon to seek from other researcher, AKA experts their bibliographies of appropriate literature.  Clearly Long isn't a researcher on the topic (or any other that I can tell).  And one must remember that the data that Ernst was contacting others for was more papers in the scientific literature.  See a larger quote from the Methods:

In addition, our own departmental files and the bibliographies of the articles thus located were searched. Several experts were also contacted for further data.

Criticism 2

Stephen Perle wrote: “What is the common feature of Ernst's citation of these deaths whose information or rather misinformation was obtained from a web site and the deaths reported by Long? Neither of these data sources were from the scientific literature. In his reply to our letter Ernst says "These cases were, however, merely added for completeness and not included in my total number of 26 cases reported in my review." Completeness? So adding people who didn't die after chiropractic spinal manipulation and weren't in the scientific literature adds completeness to a review of the scientific literature?”

Note that Professor Ernst said in his Introduction that:

Quote
“A responsible approach to serious therapeutic risks, however, requires an open discussion of the facts. In this review I aimed to provide the basis for such a discussion by summarising all fatalities which occurred after chiropractic spinal manipulation and were published in the medical literature.”

Note that he didn’t say he would *exclusively* look at the medical literature. Indeed, in the Methods section he was more specific, informing us that

Quote
“Electronic searches were conducted in the following electronic databases: Medline, Embase, AMED, Cochrane Library (September 2009)… *In addition*, our own departmental files and the bibliographies of the articles thus located were searched. Several experts were also contacted for further data. Case reports were included if they provided information on human patients who had died after receiving one or more treatments from a chiropractor.”

He goes on to say that many other fatalities seemed to have remained unpublished and gives examples of the testimony of Preston Long DC (whom it is likely that he contacted personally) which listed the family names of nine victims. Dr Long also stated that ‘many others are unknown hidden behind legal agreements of silence’. Professor Ernst then cites ‘names’ of further North American fatalities from the website www dot whatstheharm dot com

Well this isn't exactly true.  The purpose says: "In this review, I aimed to provide the basis for such a discussion by summarizing all fatalities which occurred after chiropractic spinal manipulation and were published in the medical literature." Well the problem is my anonymous critic is grasping at straws.  The purpose of looking in the departmental files or contacting experts are to find other papers in the medical literature that the search failed to find.

IF Ernst had a purpose that included all possible sources of information then that would have been in his methods.  As I noted earlier if Ernst had put the information from Long in his discussion to coincide with the assertion that many cases are remain unpublished I would have only commented on the apparent collusion with critics of chiropractic not the propriety of including Long's "testimony".

My anonymous critic goes on to note the Ernst cites the names of other American fatalities found on the web site (cited above).  Except that 5 of the 9 deaths that Ernst attributes to chiropractic spinal manipulation (in that paragraph of his paper but not in the total death count) did not die as a result of chiropractic spinal manipulation.  So again if Ernst had only talked about these deaths to buttress his argument that the literature lacks a presentation of all deaths after chiropractic spinal manipulation I would not have criticized his lack of following his own purpose.  But then again would have criticized his zeal to attribute all the deaths found on the web site to chiropractic spinal manipulation. 

Criticism 3

Stephen Perle wrote: “Wenban has detailed the commonality of wrongly ascribing adverse events of manipulation to the care of doctor’s of chiropractic.”

As Professor Ernst says in his response to Whedon et al, his original review contests that with good references. He also says he can not reasonably be expected to know of the ‘personal correspondence’ that Wenban and Bennett cited and asserts that the small discrepancies in numbers (about which they argue) are almost irrelevant.

You know if we were talking about hundreds or thousands or even hundreds of thousands of deaths one or two discrepancies wouldn't matter would they?  But and this is the amazing fact we are talking about a very small number - 26.  So adding one that doesn't belong is big.  I mean with a total of 26 in 115 years we are talking a 3.8% error.  OK the number is a small point - it just goes to the sloppy nature of the review.  Add a couple take away a couple and pretty soon you got nothing of substance in Ernst's "systematic review".
Criticism 4

Stephen Perle wrote: “Ernst says Cassidy's study has been repeatedly criticized for being flawed. The key word is repeatedly. This obviously repeatedly means more than once, which means that there must be more than one reference cited for that criticism. In fact, I think most would agree that repeatedly probably means many more than one. Well there is only one reference cited and what is that: Ernst E. Vascular accidents after chiropractic spinal manipulation: myth or reality? Perfusion 2010; 23: 73–4. No it can't be the only criticism in the scientific literature (not the blogosphere mind you - this is science we are talking about here) that Ernst can find is his own (now you get the idea about the title for the blog).”

Professor Ernst did not qualify where the study had been repeatedly criticised. Further, it you’re going to discount the blogosphere, then your blog post here should not, in any way, be taken seriously by the scientific community.

Well actually Ernst did qualify where the study had been repeatedly criticized.  He provided ONE reference to the journal he is the editor-in-chief of.  Since I know that my anonymous critic isn't a scientist (I know this from their former blog name) I'll forgive his/her ignorance about citation (and purpose above).  However, given the fact that Ernst had no problem citing a web site as a source for the purported deaths, I am sure if his source for "repeated criticism" of Cassidy was the blogoshere or other web sites (even my anonymous critic's) there's no reason to suppose he wouldn't cite them.  The fact of the matter remains that there have been no substantive criticism of Cassidy's methods in the scientific literature.  There has been only one letter to the editor by Maigne. It is my opinion that Cassidy et al adequately responded to Maigne but clearly there isn't "repeated criticism" nor criticism substantive enough to deal a death blow to the validity or importance of Cassidy's findings. 

I think one of the most important points one needs to keep in mind regarding cervical manipulation and stroke is that the only people going ape about this issue are critics of chiropractic.  It just isn't an issue to epidemiologists nor any of the stroke associations.  For example I was at a conference this year in Connecticut put on by the Connecticut Department of Public Health and the American Stroke Association on stroke in the young adult.  Not one speaker mentioned cervical manipulation the whole day.  The critical problem when it comes to stroke in the young adult is that despite its prevalence many health care providers don't recognize the condition because they think stroke is a condition of older people.  Here are the stats I heard for strokes in CT for 2009, keep in mind the population of CT is about 3.5 million

                Age          Number of deaths

45-65             2047

25-44               354

15-24                 34

4-14                   10

<4                        8

Clearly stroke is a horrible event to occur to anyone young or old.  I know first hand from family members how devastating it is but right now the evidence just does not support a causal relation between cervical manipulation and stroke.

Finally I agree completely with my anonymous critic that no one in the scientific community should take my blog or any other blog seriously from a scientific stand point.  That is why I didn't post anything on this blog until my letter to the editor was published.  As I noted in the previous posting the way science progresses is not only the publishing of ones results but that there is an opportunity for critique in the same venue via letters to the editor.  The more scientifically minded should read Ernst's paper, the letters to the editor and his response.  In fact it is this reason that I have not posted my anonymous critics comments as is.  Because I don't want to encourage people to see this person's opinion without the opportunity for rebuttal.  If they posted their name and not their URL I would have not written a whole blog post and just let the comments go and commented on them as I have done herein.

Criticism 5

Stephen Perle wrote: “Now to his critique. I won't reproduce it here…”

Why not? For anyone wishing to read it, there’s a link to the full text of it in the chiropractic section of my website. It really is quite revealing.

Well the simple answer is I don't violate copyrights.  The paper is copyrighted and neither my anonymous critic nor the other web site where I found the paper have anything about permission granted  from the copyright holder to publish the paper on the web.  The journal nor Ernst on his web site have a PDF available for free.  I guess if one is really agitated about the chiropractic profession it is acceptable practice to violate copyrights.  Zealotry trumps legality.

Also. I suggested that it is far better for people to listen to the cross-examination of Dr. Cassidy at the hearing that Long never came to.  Again here is a link to the CT-N video of Cassidy's half day on the witness stand.  Every point Ernst made and then some were tried by the two attorneys who cross-examined Cassidy.  Hear the answers from the horses mouth. 

Criticism 6

I think readers should be told that Dohos and Tragiannidis, of the Aristotle University of Thessaloniki’s Medical School in Greece, wrote to the International Journal of Clinical Practice in support of Ernst’s paper:

Quote:
“…we agree with Professor Ernst on the following points

• Vascular accidents after upper spinal manipulation can cause severe vertebral artery dissections;
• Numerous deaths have been associated with chiropractic neck manipulations;
• Many other cases are unknown behind legal agreements of silence
• Therefore the risks of chiropractic neck manipulations by far outweigh their benefits.”

Ref: Critique of review of deaths after chiropractic, 3. Dokos C, Tragiannidis A.
Int J Clin Pract. 2011 Jan;65(1):103-4.

The problem with  Dohos and Tragiannidis is that they provide no substantive evidence for any of their bulleted opinions above.   

Criticism 7 

I also think readers should be made aware of the following in the US:

Quote
"The National Quality Forum lists 28 ‘never events’ healthcare mistakes that should never happen and need to be reported. Death or serious disability from spinal manipulation is listed as no.16. But chiropractors do not have to report this because they have a loophole. The National Quality Forum demands it of clinics and hospitals but no reporting is mandated for individual doctor's offices where 99% of spinal manipulation is done. Chiropractors generally do not practise in hospitals or clinics."
Ref: Britt Harwe, open letter to the Editor, Focus on Alternative and Complementary Therapies, Volume 15, Issue 1, pages 87-88, March 2010.

OK and the point?  There are a lot of events that occur in private practices for which no reporting is mandated. 

In conclusion I am waiting for the wizard of oz to step out from behind the curtain or not. 

SMP

The self-importance of being Ernst

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Some may know Oscar Wilde's play The Importance of Being Earnest from which I've modeled the title of this blog entry.  The play is a farce where obligations are shirked by assuming false identities.  There is no discussion of false identities in this blog but there is a false presentation of objective science on the part of Dr. Edzard Ernst as Wilde writes in Act 1

 I don’t play accurately – anyone can play accurately- but I play with wonderful expression.

In July the International Journal of Clinical Practice published a paper by Dr. Ernst titled: "Deaths after chiropractic: a review of published cases."  When I read the paper I noticed some obvious errors.  As opposed to some so-called science bloggers, rather than blog about it, I scienced.  (I read once where a scientist said that one should use science as a verb, one sciences.)  
I understand that Web 2.0 allows anyone to be a critic and possibly have great influence on public opinion (gee I am writing a blog about this).  However, one of the fundamental differences between the scientific endeavor and other domains of thought is that knowledge progresses though the publishing of ones findings in a public forum after peer review and then subject to the possibility of letters to the editor which help clarify or critique or add information to that publication.  When one submits a letter to the editor they are peer reviewed, as were the original manuscripts, and if one is using a bibliographic database such as PubMed the letters to the editor are hyperlinked to the record for the original manuscript so that people can find these important commentaries.

Here is a link to our letter to the editor on PubMed's web site.  Copyright issues prevents me from providing the letter to my readers.  We initially wrote a much longer letter but were informed after submission that the journal's maximum size is 500 words for a letter.  I will provide the added detail in this blog.
The paper the letter is in regard to is: Ernst E. Deaths after chiropractic: a review of published cases. Int J Clin Pract. 2010 Jul;64(8):1162-5.  In this paper Ernst's purpose was 

In this review, I aimed to provide the basis for such a discussion by summarising all fatalities which occurred after chiropractic spinal manipulation and were published in the medical literature.

In the results section of the paper he has a paragraph that is, to say the least, very interesting when one thinks of the purpose.   Herein he describes "the testimony of the chiropractor Preston Long for a court in Connecticut recently listed the family names of nine victims."  Ernst cites this with: "Presentation by Dr Preston Long DC to State of Connecticut. Connecticut State Board of Chiropractic Examiners. Hartford Connecticut.
25 October 2009.  There was never a hearing before the State Board of Chiropractic Examiners on October 25, 2009.  The hearing was in January of 2010 and because Long did not appear to under oath attest to his pre-submitted testimony it was, in accord with the procedural rules in CT not accepted and thus not part of the public record.  One wonders how does Ernst get this document when it was not public.  I have a copy as I was on the witness list and these pre-submitted testimony documents I was told were not to be made public until the board hearing.  


Anyone wishing to see the hearing where Long's testimony is discussed should go to the CT-N web site here.
In that same paragraph Ernst cites nine deaths from chiropractic  spinal manipulation that he found on a web site.  When I read Ernst's paper one name stood out in my mind, Kimberly Lee Strohecker.  I know a fair bit about Ms. Strohecker's very unfortunate death.  I wrote about it in a 2004 ethics article titled J'Accuse...! (I Accuse).  This article is about the death of Ms. Strohecker after a chiropractor got her to stop taking her anti-seizure medication.  At least the federal court barred the chiropractor from ever practicing chiropractic again along with prison and a fine.

Yes her death was the result of a chiropractor's actions but they weren't due to chiropractic spinal manipulation.  So I reviewed all the other people Ernst cited as dying from chiropractic spinal manipulation on the web site and discovered the Ms. Strohecker was one of 5 whose death might have been because of a chiropractors actions but weren't the result of chiropractic spinal manipulation.

What is the common feature of Ernst's citation of these deaths whose information or rather misinformation was obtained from a web site and the deaths reported by Long?  Neither of these data sources were from the scientific literature.  In his reply to our letter Ernst says "These cases were, however, merely added for completeness and not included in my total number of 26 cases reported in my review."  Completeness?  So adding people who didn't die after chiropractic spinal manipulation and weren't in the scientific literature adds completeness to a review of the scientific literature?

Now some reading this will say - gee that's picky.  Well the point is ones method must fit ones stated purpose.  Now if he had said in the discussion that there may be many more deaths after chiropractic spinal manipulation that aren't reported in the scientific literature and then cited these he would have at least stood on safer ground.  Still 5/9 cases he said were after chiropractic spinal manipulation weren't.  As we noted in our letter to the editor: "When obvious facts are wrong, the veracity of other facts, not as easily verified, must come into question."  Science works in part because we have to have faith that what people write in their papers is in fact the truth.  It is not truthful to say 9 people died when only 4 did.  Thus can we trust the rest of what Ernst tells us?

Also Ernst cites an event that never occurred, Long's non-testimony before the CT Chiropractic Board.  So again he cites something that is obviously not true.  Thus can we trust the rest of what Ernst tells us?  Some might say it is an honest error which if he was a newbie to scientific publishing I'd say give him a pass but I just did a PubMed search for Ernst E and found 1426 papers.  I don't think he can claim to be a newbie.

Ernst cites a paper by Dziewas et al as presenting another case of a person who died after chiropractic spinal manipulation.  However, one of the great features of modern electronic bibliographic searching technologies, such as  PubMed, which Ernst used, is that letters to the editor also are found with the citation for every paper.  When searching PubMed for Dziewas one finds a letter to the editor by Wenban.  Wenban reported that the treatment was not provided by a chiropractor and thus cannot be chiropractic spinal manipulation.  Wenban has detailed the commonality of wrongly ascribing adverse events of manipulation to the care of doctor’s of chiropractic. 

A couple of the letters to the editor note that Ernst missed in his discussion the study by Cassidy et al that investigated the association between stroke and seeking care of a chiropractic physician or a medical physician and found no excess risk for seeking care with a chiropractic physician.  I've blogged about this previously.   In Ernst's reply he says about Cassidy's study "it has been repeatedly criticised for being seriously, perhaps even fatally, flawed e.g. (8). The ‘inconvenient truth’ might thus turn out to be a 'convenient untruth’."  A long time ago I read an article that talked about somethings one can do to simply determine the validity of a paper one reads.  One of those is references.  Above Ernst says Cassidy's study has been repeatedly criticized for being flawed.  The key word is repeatedly.  This obviously repeatedly means more than once, which means that there must be more than one reference cited for that criticism.  In fact, I think most would agree that repeatedly probably means many more than one.  Well there is only one reference cited and what is that: Ernst E. Vascular accidents after chiropractic spinal manipulation: myth or reality? Perfusion 2010; 23: 73–4.

No it can't be the only criticism in the scientific literature (not the blogosphere mind you - this is science we are talking about here) that Ernst can find is his own (now you get the idea about the title for the blog).  Anyway, you mean to tell me that none of the critics of this study had the testicular fortitude to write a letter to the editor?  Cassidy's study was published in Spine and was part of the WHO's Bone and Joint Decade's Cervical Spine Task Force reports.  Well OK Ernst didn't see fit to write his critique in the journal it was published in, as my colleagues and I did about Ernst's paper.  You know those newbies to scientific publishing don't know that you should submit critiques to the journal it was written in.  Well you remember those 1426 citations to Ernst in PubMed just 204 are letters to the editor.  OK but let's look at his cited critique.  

Ernst E. Vascular accidents after chiropractic spinal manipulation: myth or reality? Perfusion 2010; 23: 73–4.

Don't search too hard for this in PubMed.  It's not there. The journal name is wrong.  I know newbies sometimes get their citations wrong especially when they don't know the journal too well.  Here is the proper citation.

Ernst E. Vascular accidents after chiropractic spinal manipulation: Myth or reality? Verlag Perfusion GmbH. 2010;23:73-4.

What do I know about Verlag Perfusion GmbH.  If you look at their web site you'll see it is a German publication and the first editor listed is...Ernst.  So I guess he's unfamiliar with the proper name for the journal.
Now to his critique.  I won't reproduce it here but instead suggest listening to Cassidy answer these questions as they were posed to him before the CT Chiropractic Board you can see his testimony here.

Ernst in his paper on deaths after chiropractic spinal manipulation also says that there is no benefit to spinal manipulation.  What's his reference for that.  You guessed it, his own narrative review.  Thus he ignores a growing body of systematic reviews showing benefit to spinal manipulation (1- 9)

There is one more item.  In that list of 1425 papers in PubMed written by Ernst E there are 299 systematic reviews of these I count 37 which there is only one author.   Of the 299 systematic reviews 17 are about the chiropractic profession.  Has a real fixation on us doesn't he.  Of the 37 systematic reviews with only one author 10 are about chiropractic.  Or to put is another way of the 17 systematic reviews about the chiropractic profession 10 are single author systematic reviews.  This is astounding.  Why?  Because standard practice in systematic reviews is to have at least two people.  What is considered to be the preeminent international group conducting systematic reviews, The Cochrane Collaboration never does any reviews with one reviewer.  Its just not done by almost anyone but...Ernst.  In fact from the Cochrane Handbook:

It is essential that Cochrane reviews be undertaken by more than one person. This ensures that tasks such as selection of studies for eligibility and data extraction can be performed by at least two people independently, increasing the likelihood that errors are detected. If more than one team expresses an interest in undertaking a review on the same topic, it is likely that a CRG will encourage them to work together.

 Well the self-importance of being Ernst is that he's the only expert whose opinion counts to Ernst.

SMP

1. Oliphant D. Safety of spinal manipulation in the treatment of lumbar disk herniations: a systematic review and risk assessment. J Manipulative Physiol Ther. 2004 Mar-Apr;27(3):197-210. Pubmed record
2. Fernandez-de-Las-Penas C, Alonso-Blanco C, Cuadrado ML, Pareja JA. Spinal manipulative therapy in the management of cervicogenic headache. Headache. 2005 Oct;45(9):1260-3. Pubmed record
3. Chou R, Huffman LH. Nonpharmacologic therapies for acute and chronic low back pain: a review of the evidence for an American Pain Society/American College of Physicians clinical practice guideline. Ann Intern Med. 2007 Oct 2;147(7):492-504. Pubmed record
4. Hawk C, Khorsan R, Lisi AJ, Ferrance RJ, Evans MW. Chiropractic care for nonmusculoskeletal conditions: a systematic review with implications for whole systems research. J Altern Complement Med. 2007 Jun;13(5):491-512. Pubmed record
5. Bronfort G, Haas M, Evans R, Kawchuk G, Dagenais S. Evidence-informed management of chronic low back pain with spinal manipulation and mobilization. Spine J. 2008 Jan-Feb;8(1):213-25. Pubmed record
6. Hurwitz EL, Carragee EJ, van der Velde G, Carroll LJ, Nordin M, Guzman J, et al. Treatment of neck pain: noninvasive interventions: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders. Spine. 2008 Feb 15;33(4 Suppl):S123-52. Pubmed record
7. Bronfort G, Haas M, Evans R, Leininger B, Triano J. Effectiveness of manual therapies: the UK evidence report. Chiropr Osteopat. 2010;18:3. Pubmed record
8. Gross A, Miller J, D'Sylva J, Burnie SJ, Goldsmith CH, Graham N, et al. Manipulation or mobilisation for neck pain: a Cochrane Review. Man Ther. 2010 Aug;15(4):315-33. Pubmed record
9. Miller J, Gross A, D'Sylva J, Burnie SJ, Goldsmith CH, Graham N, et al. Manual therapy and exercise for neck pain: a systematic review. Man Ther. 2010 Aug;15(4):334-54. Pubmed record

Science, sometimes - stroke and chiropractic

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The Connecticut Board of Chiropractic Examiners ruled on the issue of informed consent.  There was a hearing on a declaratory ruling regarding informed consent and stroke.  The board heard four days of testimony (which are available as videos at CT-N).  Although the board's ruling hasn't yet hit the internet where I can find the exact text, it appears from newspaper reports that they ruled affirming that informed consent is the law in Connecticut but refused to require specific consent about a risk of stroke.  Both the New Haven Register and the Hartford Courant have weighed in on this issue and it appears that science isn't the strong suit for either newspaper.

Both papers believe that there is a risk of stroke from cervical manipulation.  Of course the two groups that advocated before the board for the ruling to require telling prospective chiropractic patients of the risk also believed there is a risk. To me what I have learned being part of this process is that science matters to many people only when it serves their interests. 

Nature of science

Science is an epistemological theory.  Epistemology is the study of how we acquire knowledge.  Science, as we know it, is just one method to acquire knowledge through what's called the scientific method.  Wikipedia's explanation of the scientific method is well done (at least today).  Simply, the method is to observe some phenomenon, create a hypothesis (i.e. a prediction) about that phenomenon, then test that hypothesis by controlled observation, an experiment. 

There are other epistemologies besides science.  For example divine revelation where knowledge comes from a deity. Some have called my profession, chiropractic a cult because there are some in the profession whose epistemology is based upon the work of a guru, typically BJ Palmer.  At one time most of medicine was based upon some guru's dogma.  For example anatomy was controlled by the works of Galen (1st - 2nd century of the common era) who really didn't have a clue what was in the human body - he'd looked at monkeys as human dissection wasn't allowed in his time. It wasn't until a skeptic Andreas Vesalius (16th century) applied the empirical method - noting that the bodies he dissected didn't look the way Galen said that anatomy progressed beyond the dogma of Galen.

One common epistemology is the use of anecdotes.  You know, "I once knew a guy who smoked a carton of cigarettes a day for 70 years and never got lung cancer.  So cigarettes are safe."  OK that's extreme but anecdotes have a tremendous hold upon our thinking and often it is very difficult to let science triumph when anecdote sits in contradiction of the science. Anecdotes which in health care publications are called case reports are very good at hypothesis generation, remember the scientific method is based upon an observation generating a hypothesis.  Case reports can help generate a hypothesis but never can validate the hypothesis.  I've heard it said often amongst skeptics of chiropractic that the pleural of anecdote is anecdotes not evidence.  I'll come back to this quote again!

Autism and Vaccinations

I know it looks like I'm completely switching gears but there is a logic to my digression.  As I have thought a lot about stroke and manipulation and autism and vaccinations I've come to see that they are analogous situations.  Think about this, a family has what appears to be a healthy normal baby.  They are in this blissful state of early parenthood enthralled with the baby who is developing a similar love for them.  Then suddenly the developing relationship on the babies side changes and the child becomes distant.  The parents seek advice and find that their now more withdrawn child appears to have autistic spectrum disorder.  To the parent this can be a devastating event. They want desperately to find a cure and if there isn't a cure (which there doesn't seem to be) they want to blame someone, something. This is only natural.  The parents feel as if someone, something has taken their child away from them.  Then they hear about a supposed link between autism and vaccinations.  Now they have people to blame.  They can blame the vaccine manufactures.  They can blame the government for trying to tell us that vaccines are safe. They can blame their doctors for giving their baby this poison which caused the problem.  To hear the anti-vaccination folks go on about autism and vaccines is to hear the voice of anger and vindictiveness.  They are not malicious people just untrained in the ways of science and prone to letting their emotions have greater sway over how they look at the evidence.

What about the evidence?  Those parents when confronted with the scientific evidence that does not support their belief that autism is caused by the vaccine, reject the evidence.  What is the basis for the rejection, valid critique of the science?  No, usually it is what comedian Stephen Colbert called truthiness.  Truthiness, which was the Merriam-Webster word of the year in 2006, is defined as: "Truth that comes from the gut, not books," and "The quality of preferring concepts or facts one wishes to be true, rather than concepts or facts known to be true."

Then a whole support industry develops around this belief.  There are organizations whose purpose is to advocate on behalf of the parents and spread the word that autism is definitively caused by vaccines.  This theory is advanced in such a way that reading the web one might believe it was the only one.

I was a participant in a webcast on vaccines for the California Department of Public Health titled "Wading through the Confusion".  As one of my colleagues on the webcast, David G. Amaral, PhD, an autism researcher from the UC Davis M.I.N.D. Institute lamented is that there is inadequate research money available to find the cause of autism because the theory advocated by these groups has so dominated the discussion.

[Any one wishing to know more about this battle should read Paul Offit's book Autism’s False Prophets: Bad Science, Risky Medicine, and the Search for a Cure. The NYTimes article on Offit is enlightening about the lack of civility of public discourse on this issue.] 

Back to Stroke

Now think about ischemic strokes.  Isn't this what happens after a stroke in a younger person.  I mean we sort of think of stroke as a disorder that affects the elderly and it is.  The CDC lists death from stroke as the third most common cause of death behind heart attacks and cancer.  The rate of stroke increases dramatically as one ages. Stroke is a life changing event that affects not only the person who may be disabled, but the entire family and other caregivers as well. Utility analyses show that a major stroke is viewed by more than half of those at risk as being worse than death. (1)

So a younger person, say in their 40s - 50s has a ischemic stroke.  That person and their family are going have the same desire as the family who finds their child has developed autism, find someone to blame.  Well instead of a radicalized group of parents spreading the word that vaccines are the cause for autism there is a radicalized group of patients spreading the words that it must be a visit to a chiropractor. This theory that chiropractic cervical manipulation is the cause of strokes in the young has become so common that many MDs speak as if this is an established fact.  They don't really know what the research says about stroke but couple their distrust of chiropractic (2) which I think is a result of the AMA's illegal boycott(3) and it's easy to see how they would assume the connection between chiropractic care and stroke is valid.  Plus why search the literature to find this out, most people they know will tell them it is true.  It seems scientific evidence doesn't always matter.(4)

What is the epidemiology of these strokes?  They are rare representing 2% of all ischemic strokes but 10 to 25 percent of strokes in the young and middle aged.(5)  These facts are not well known so when someone in who is young or middle aged presents to a hospital with a stroke everyone wants to know why.   Given the bias and bad information then the question comes, "did you see a chiropractor within the past month?"  This only serves to expand the perceived value of this belief.  It is not uncommon to hear someone say that the risk is proven.  Proof is a word I tell my students that they can never use when referring to biomedical research.  There is either evidence that supports or refutes a particular hypothesis.  IF they want PROOF then their career choice should become mathematics not health care. 

Or that there is 80 years of science backing this up.  Well time to go back to that earlier quote: "the pleural of anecdote is anecdotes not evidence."    There isn't an 80 year history of science with respect to the association between cervical manipulation and stroke, there is an 80 year history of anecdotes that appears in the scientific literature.  The real science behind this issue has a much shorter history.  We get a survey of neurologists in 1995 (6) with a very poor response rate and which suffers from referral bias. (7)  Plus a survey doesn't establish cause and effect.  There are many studies of cases that have tried to discover the incidence.  For example this paper by Haldeman et al which estimated that one chiropractor in 48 would during the course of their practice career would be made aware of an arterial dissection following cervical manipulation.  But none of these papers actually evaluated the risk. 

There are only three studies that have evaluated the risk of stroke after manipulation.  And all three agree there is an association.  (9- 11)  The first two found a risk (9, 10) and the third (11) finding the same association provided evidence that explains the first two.  Cassidy et al (11) used the same data sources as Rothwell et al (9) but Cassidy et al study investigated one thing neither Smith (9) nor Rothwell (10) did and that is they determined the background rate of these strokes.  The issue is if the rate of strokes after chiropractic care was greater than the background rate (those that were occurring spontaneously not caused by the manipulation) then we would know what the added risk was due to manipulation. The finding, the rate of strokes in patients under 45 seeking care from their primary care physician was identical to the rate for those who had seen a chiropractor.  Thus seeking chiropractic care produced no extra risk for stroke over and above the background rate.  It appears that patients about to have a stroke from a dissection of a vertebral artery (the kind blamed on chiropractic for 80 years) seem to go to a doctor (a medical doctor or a chiropractic doctor) and the only reason the association between chiropractic and stroke appeared to be strong and not for PCPs is that no one asks the question in the emergency room, "did you see your MD within the past month?"

Some have complained that Cassidy et al was a "statistical study" (see this opinion piece or listen to Dr. Murray Katz's testimony before the Connecticut Board of Chiropractic Examiners)  That's almost comical as a critique if not that it might ring true to people who don't understand biomedical research.  Those same critics never said that Rothwell (9) and Lee (10) were "statistical studies" which they are. 

In the publication BottomLine Health there is an article about stroke risk.  The author Dr. Steven Messe essentially dismisses cervical manipulation as a risk factor based upon Cassidy et al's work.(12) 

The nature of science is that what was known one day may change the next.  This isn't often comfortable to the average person but it is the way it is.As the late Prof. Natalia Romalis-Reytblatt (she was a math professor at UB and UB’s 2006-07 Professor of the Year) wrote:

Mathematical results are either false or true (that is, proven or false) and nothing in between. Mathematics is one of the oldest fields of study and, probably, the only field whose findings are not reversed over time, only accumulated.

Math doesn't reverse it's findings but biomedical science does.  A few years ago I wrote about the risk of stroke from cervical manipulation.  But then the evidence changed.  So in the end this is an argument about looking at the science or ignoring the science and using emotion or choosing to use old science only.  To hear the science you can listen to Dr. David Cassidy testify before the board.  You can decide. 

SMP

1. Goldstein LB, Adams R, Alberts MJ, Appel LJ, Brass LM, Bushnell CD, et al. Primary prevention of ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council: cosponsored by the Atherosclerotic Peripheral Vascular Disease Interdisciplinary Working Group; Cardiovascular Nursing Council; Clinical Cardiology Council; Nutrition, Physical Activity, and Metabolism Council; and the Quality of Care and Outcomes Research Interdisciplinary Working Group: the American Academy of Neurology affirms the value of this guideline. Stroke. 2006 Jun;37(6):1583-633.  (this paper is available for free here)
2. Busse JW, Jacobs C, Ngo T, Rodine R, Torrance D, Jim J, et al. Attitudes toward chiropractic: a survey of North American orthopedic surgeons. Spine (Phila Pa 1976). 2009 Dec 1;34(25):2818-25. (Pubmed link)
3. Getzendanner S. Permanent injunction order against AMA. Jama. 1988;259(1):81-2. (Pubmed link)
4. Gabbay J, le May A. Evidence based guidelines or collectively constructed "mindlines?" Ethnographic study of knowledge management in primary care. Bmj. 2004 Oct 30;329(7473):1013.(this paper is available for free here)
5. Schievink WI. Spontaneous dissection of the carotid and vertebral arteries. N Engl J Med. 2001 Mar 22;344(12):898-906. (Pubmed link)
6. Lee KP, Carlini WG, McCormick GF, Albers GW. Neurologic complications following chiropractic manipulation: a survey of California neurologists. Neurology. 1995;45(6):1213-5. (Pubmed link)
7. Haldeman S, Carey P, Townsend M, Papadopoulos C. Clinical perceptions of the risk of vertebral artery dissection after cervical manipulation: the effect of referral bias. Spine J. 2002 Sep-Oct;2(5):334-42. (Pubmed link)
8. Haldeman S, Carey P, Townsend M, Papadopoulos C. Arterial dissections following cervical manipulation: the chiropractic experience. CMAJ. 2001 Oct 2;165(7):905-6. (this paper is available for free here)
9. Rothwell DM, Bondy SJ, Williams JI. Chiropractic manipulation and stroke: a population-based case-control study. Stroke. 2001;32(5):1054-60. (this paper is available for free here)
10. Smith WS, Johnston SC, Skalabrin EJ, Weaver M, Azari P, Albers GW, et al. Spinal manipulative therapy is an independent risk factor for vertebral artery dissection. Neurology. 2003 May 13;60(9):1424-8. (Pubmed link)
11. Cassidy JD, Boyle E, Cote P, He Y, Hogg-Johnson S, Silver FL, et al. Risk of vertebrobasilar stroke and chiropractic care: results of a population-based case-control and case-crossover study. Spine. 2008 Feb 15;33(4 Suppl):S176-83. (Pubmed link)
12. Messe SR. Stroke Risk. BottomLine Health. 2010;24(3):1-2. 

Chiropractic In the News Downunder

The Australian TV show Lateline recently did a piece on chiropractic. This was motivated by the British Chiropractic Association's libel law suit against Simon Singh. On balance I think this was pretty good news story. From when I began in the profession, in 1979, as a student at Texas Chiropractic College and for a long time after that it seemed to me that the media were just hatcht men for the AMA. Since Judge Getzendanner's 1988 decision in the Wilk v. AMA law suit the media has been kinder.

The Lateline video includes interviews with Bruce Walker, DC, MPH, DrPH. and Chris Maher, PhD. Dr. Walker is the editor in chief of Chiropractic and Osteopathy an open access, peer-reviewed online journal that aims to provide chiropractors, osteopaths and related health professionals with clinically relevant, evidence-based information. I am an one of four associate editors for C&O. So often it seems that print or video media edit away the substance of a interviewee. I think Dr. Walker's interview was treated fairly and he gets across his point about the evidence regarding chiropractic care.

Dr. Walker notes that chiropractic care should primarily be for the musculoskeletal system. In C&O I am a co-author of a couple of papers that suggest that chiropractors should mostly be non-surgical spine specialists because substantially what we do is spine care.

Dr. Maher, who is a physical therapist discusses recent research that found that manipulation is no better than standard medical care. Unfortunately his use of the term manipulation is unusual. Only 5% of the subjects in this study actually had manipulation and the rest had mobilization as a treatment. Thus the study does not actually evaluate spinal manipulation. with Dr. Jeff Hebert of the U of Utah, I have published a letter to the editor pointing out this inconsistency.

There is also an interview with an MD about stroke in which he again ignores the most recent research showing that manipulation does not cause stroke.

SMP

Stroke of genius

I have discovered a real stroke of genius. If one says often enough and has enough money to put billboards up that a chiropractor caused a stroke, then it must be true. Madison Ave. discovered this years ago.

Here's a news piece about the billboards and the women who put them up.
http://wcbstv.com/topstories/stroke.chiropractor.billboard.2.948444.html

(BTW there is no such word as chiropractry as used in the CBS news piece - they must have forgotten to use a spell-checker)

Surely if these billboards are up there must be some truth to it, no? Well if you asked me the question about a year ago I would have said, yes there does appear to be a risk of stroke after seeing a chiropractor. I have advocated that even though the odds were one in five hundred thousand treatments to one per five million treatments that one should still tell prospective patients about this small risk.

But then a huge study was published early last year.

Cassidy JD, Boyle E, Côté P, He Y, Hogg-Johnson S, Silver FL, et al . Risk of vertebrobasilar stroke and chiropractic care: results of a population-based case-control and case-crossover study. Spine. 2008;33(4 Suppl):S176-83.

Cassidy et al have found that the likelihood of having a stroke after seeing a chiropractor is the same as the likelihood of having a stroke after seeing an MD. Thus, the previous research that had found an association between chiropractic care and strokes were showing only half the picture because they didn't look at whether the association existed with other professionals. The problem isn't the intervention it is that one seeks care from a health professional. This is sort of how some advertisements work.

4 out of 5 ______ like this product. They don't tell you that 4 out of 5 are just as happy with the competitor's product. I've blogged on this before (see Katz and dogma) but I figure if repeating something that isn't true over and over will improve the odds that it will be believed maybe my stroke of genius is to repeat what is true.

It is critical to understand that association does not establish causation. If association did let us know what caused something then think about this. When one sees a photograph or video of a house fire in the news media one always sees fire engines. One might conclude that fire engines are there to cause the fire (as they are in Ray Bradbury's book Fahrenheit 451).
On the health front at one time research clearly showed the association between salt intake and hypertension. Eventually, it was discovered that salt intake isn't the culprit, it's fats and other elements of a poor diet. The reason salt looked as if it was the cause is because in the U.S. fatty foods tend to be salty, think french fries.

Well this stroke issue is looking similar to salt. The reason some people have strokes after seeing a chiropractor and a medical doctor is because they have the early symptoms of an event that may lead to a stroke and those symptoms send them to a doctor's office (be that a chiropractic or medical doctor).

In a way this is also similar to the issue of autism. Parents have what appears to be a normal child, the child gets immunized and then they notice abnormal behavior that turns out to be part of autism spectrum disorder. Did the immunization cause the autism. The best evidence says no but the parents searching for some reason for their child's behavior grasp at the immunization as the cause.

Similarly, the person who has a stroke grasps for a cause, and if they saw a chiropractor a malpractice attorney is often ready to say that the cause is the chiropractor.

Does this mean that chiropractic care is completely without any complications. Clearly any treatment that has the power to help has the power to hurt. It is just the best evidence right now doesn't support the association between cervical manipulation (usually done by chiropractors but now more and more PTs, MDs and DOs are doing this) and stroke.

What is really interesting about this whole campaign against chiropractic care is that the campaign isn't about cervical manipulation, which some PTs, MDs and DOs do it is about chiropractic cervical manipulation only. Granted DCs use spinal manipulation more than any other type of health professional and perform the vast majority of manipulative procedures, still why don't the people with the billboards and other media say cervical manipulation may cause a stroke instead of saying chiropractic might cause a stroke? This is another critical question because IF there was a problem with cervical manipulation is it only at the hands of a DC. There is one study that critics of chiropractic have often cited to show the risk of chiropractic care. This study from Germany purports to report on vertebral artery dissections after chiropractic care. Unfortunately for those who use this as evidence of chiropractic's harm only 11% of the subjects in this study were treated by chiropractors but 50% were treated by MDs and 14% by PTs. But to read the title or abstract alone one would be convinced that it is about care provided by chiropractors. Here's the citation (if you click on the link you can read the abstract):

Reuter U, Hamling M, Kavuk I, Einhaupl KM, Schielke E. Vertebral artery dissections after chiropractic neck manipulation in Germany over three years. J Neurol. 2006 Jun;253(6):724-30.

Again if the people who put up the billboard were concerned with public safety why put up billboards that say chiropractic rather than cervical manipulation?

SMP

Katz and dogma

I was talking to a friend today and she brought to mind an exchange between Murray Katz, MD and me from the McGill University, Faculty of Medicine, Continuing Medical Education discussion board. I thought that I would post some of it here.

Dr. Katz had presented an anti-chiropractic diatribe at McGill which is "so full of fabrications, extrapolation and cherry-picked use of the literature that his presentation really should be prefaced with a warning that this is fiction."

I was asked a question on the discussion board after posting the comment above (and more) about "high neck manipulation." I cited the recent literature on the topic:

Cassidy JD, Boyle E, Côté P, He Y, Hogg-Johnson S, Silver FL, et al . Risk of vertebrobasilar stroke and chiropractic care: results of a population-based case-control and case-crossover study. Spine. 2008;33(4 Suppl):S176-83.

This is rather compelling evidence that the association seen in previous studies between cervical manipulation and vertebrobasilar stroke was actually an association between vertebrobasilar stroke and seeking the care of a health care professional. We know this from Cassidy et al because the association between stroke and seeing a chiropractor was identical to the association between stroke and seeing a primary care physician (PCP) AKA a medical doctor. Thus manipulation was not associated with stroke just seeking care was.

Then Katz joined in the discussion:

Re: High Neck manipulation Posted by Murray on Jul 23, 2008 9:38
The comment on various studies by Mr. Perle (with all due respect none of his many degree were obtained under the direction of a Faculty of Medicine) are typical of the chiropractic “spin”. There are endless studies on homeopathy but there is more urine from a shark swimming on Mars than the ingredients on the bottle. Likewise, this is no such thing as chiropractic vertebral subluxations. The study he quotes using billing numbers is typical of chiropractic studies which Wallace Sampson and J. William Kinsinger wrote about in their paper “Producing Quack Studies for Quackery”. To show the extent of this quackery, a German study using actual hospital records and also going backwards found 36 cases of chiropractic stroke. Chiropractors want us to waste our time discussing their studies. There are a few chiropractors who have crossed over to science. These admit freely there is no such thing as subluxations. They no longer claim to have meaningless degrees. They start with the basic question, why are 200 million high neck manipulations a year being done on everyone from newborn babies to senior citizens. What is the diagnosis? The following commentary was published last week in the Calgary Herald in Alberta. It deals directly with the issues. Re: "Anecdotes are not enough to condemn chiropractors," Susan Martinuk, Opinion, July 18. Susan Martinuk's column is typical of chiropractic spin. Seventy years of scientific literature from all over the world, the warnings of neurologists all across Canada, three coroners' reports involving the deaths of three young women in Canada as well as an endless number of life-devastating strokes are not anecdotes! Almost without exception, all of these victims of chiropractic neck manipulation stroke and death have a number of things in common. They did not have pain in the highest neck area. They had their highest neck manipulated with the diagnosis of vertebral subluxations, something which does not exist. No one should die or live a disabled life for a condition that does not exist. Highest neck manipulation was done on them at almost every visit no matter what the complaint, sometimes 50 or 100 times, or more. Does it ever work? From newborn babies to senior citizens, Albertans are being told they have vertebral subluxations and need to have the highest neck manipulated. This is a scam and a fraud paid for out of the public purse and your own pockets. Victims and physicians are asking for six reasonable and scientific restrictions to be placed on all chiropractic highest neck manipulation. None of these will prevent the use of scientific manual therapy for neck pain, most of which is done responsibly by physical therapists. These restrictions are that highest neck manipulation should not be done on babies and children, not for claims that this can provide "wellness" to the body, not 50 times on the same person, not to claim to treat liver, heart or other organ diseases and most important, not for the claim that there are vertebral subluxations in the highest neck area. Physical therapists abide by these restrictions and hence have no strokes or death due to neck manipulation. The Minister of Health of Alberta has already been warned to enforce these restrictions and since Sandra Nette's stroke, we now have another case in Alberta of a young man who suffered a locked-in stroke and has come partly out of it. There are others. The reason the College of Chiropractors of Alberta, there to supposedly protect the public, will object to these sensible restrictions is that their officials all believe in this quackery. In my own experience, I was placed on a table from which a part suddenly dropped away and as a result, I had a stroke. The College of Chiropractors fully supports such quack machines claiming they can treat neck pain? Never allow a chiropractor to place you on a drop table machine. In the words of the Wellness Center in California, never agree to neck manipulation. Diana Dingley, Chestermere, (a stroke victim), and J. William Kinsinger, MD, Edmond, Okla. © The Calgary Herald 2008

Here is my reply:

Re: Re: High Neck manipulation Posted by Stephen on Aug 02, 2008
7:08

Dear Dr. Katz,

It appears to me that somehow having a medical degree has conferred upon you a level of arrogance that most other professionals do not possess. Who gave you the right to determine who has or does not have a valid doctorate? I think that government has that prerogative and it has spoken in Canada, despite your views. By your thinking, I ought refer to you as Mr. Katz because, with all due respect, none of your degrees were obtained under the direction of a Faculty of Chiropractic. This rather juvenile of you don’t you think?

You write that “few chiropractors who have crossed over to science”. I searched pubmed and cannot find a single paper in the peer reviewed literature that you have authored only one letter to the editor. This sounds as if the pot is calling the kettle black. Your degree and likewise your comments do not provide me with evidence that you have “crossed over to science”. Coming from a scientific profession does not mean one is scientific. One actions and words speak louder than ones degree.

On the other hand my publishing record in the peer reviewed and pubmed indexed literature is available.

http://tinyurl.com/6y34tf

Likewise one can find my writings on ethics within chiropractic.

http://www1bpt.bridgeport.edu/~perle/ethics.htm

http://www.acatoday.org/level2_css.cfm?T1ID=15&T2ID=160

And finally I am quite clear when it comes to subluxations.

http://www.chiroandosteo.com/content/13/1/17

I suggest you read what I have published and stop assuming I defend bad chiropractic practice, any more than I should accuse you of defending bad medical practice.

Of interest is the fact that the Cassidy (1) study I cited is published in the preeminent orthopedic journal. I can’t find Sampson and Kinsinger’s paper in pubmed. I guess it wasn’t published in quite as prestigious journal. One wonders what the scientific world has come to when such an important work is relegated to the scientific backwater and the quack studies of quackery that use billing records written by people with meaningless degrees is published in such a prestigious journal. Or maybe Dr. Katz’s view of the world is a bit askew.

Cassidy’s (1) study is a population based study rather than a retrospective review of hospital records of some hospitals, which the German study (which Dr. Katz alludes to but does not cite (2) is). It turns out that in the German study 50% of the so-called “chirotherapy” was provided by orthopedic surgeons and only 11% was provided by chiropractors. (2-3) I would suggest Dr. Katz, when using a study to cite the hazards of chiropractic care one should carefully read the study to ensure that the so-called chiropractic treatment was actually provided by chiropractors and not medical doctors.

One could debate the merits of each study but that does not appear to be what Dr. Katz would like to do. His modus operandi appears to be ad hominem attacks, the use of spurious literature, misquoting his own sources and “scientific” debate via newspaper. This is not an exercise I choose to engage in any longer. If the level of debate rises to a professional level, I shall respond appropriately.

Stephen M. Perle, D.C., M.S.

[1] Cassidy JD, Boyle E, Cote P, He Y, Hogg-Johnson S, Silver FL, et al. Risk of vertebrobasilar stroke and chiropractic care: results of a population-based case-control and case-crossover study. Spine. 2008 Feb 15;33(4 Suppl):S176-83.

[2] Reuter U, Hamling M, Kavuk I, Einhaupl KM, Schielke E. Vertebral artery dissections after chiropractic neck manipulation in Germany over three years. J Neurol. 2006 Jun;253(6):724-30.

[3] Wenban AB. Inappropriate use of the title 'chiropractor' and term 'chiropractic manipulation' in the peer-reviewed biomedical literature. Chiropr Osteopat. 2006;14:16.

If anyone is interested in the whole exchange please go to McGill's web site

Again if anyone is interested in the best evidence on chiropractic stroke read the study by Cassidy et al

SMP