Following the evidence base is excellent – or is it?

I have started my section on EBM, as it is commonly known, with an example of decision-making by management based on no evidence – or, to be fair, bits of evidence that do not add up (this is the bare below the elbows issue). However there are numerous examples of clinical trials which have produced good evidence that cannot be relied upon.[1]

Three examples in my own specialty come to mind. In one case a lack of anatomical knowledge prejudiced the outcome (also true of the second) and in the third a failure to understand exponential data meant that like was not compared with like.

Bear these examples in mind when you look at any clinical trial.

Do you know your anatomy (1)

Colleagues in a neighbouring Trust performed a sequential audit on the benefit of steroid injection for frozen shoulder – technically known as capsulitis, and basically a severe inflammation of the joint between long arm bone (humerus) and shoulder blade (scapula) – the glenohumeral joint. The injections were administered by a single practitioner, and the results suggested little or no benefit. The injections had been given by the lateral approach, which enters another part of the shoulder mechanism – the joint under the tip of the shoulder blade (subacromial joint). This and the glenohumeral joint are quite separate unless the main shoulder muscle, the rotator cuff, has torn – an anatomical fact not appreciated by the study sponsors, probably because rheumatologists don’t read orthopaedic textbooks and never sat in orthopaedic clinics. So, one can reasonably suppose that injection of one joint will only rarely have any effect on the other, and that as the wrong joint had been injected the study was useless.

This failure led to some debate. It became clear that there was disagreement on the management of shoulder problems that extended further to the actual accurate assessment of them. We set up a little study which showed that even experts did not agree on a diagnosis even when they saw the patients together[2]. There are a number of published trials which have fallen into the same trap – but are still adduced as evidence when people attempt to assess the efficacy of joint injections.  The first thing you must do is ensure that you are actually treating the part that need treating.

Do you know your anatomy (2)

People are still treating sacroiliac joint strain. This is diagnosed by finding – pain over the sacroiliac joints. Injection treatment relieves symptoms. QED.

I am not so sure. A registrar in our department, when I was a senior registrar, came to me asking my views on this syndrome. He could not see no logic in it. Inflammation and infection – yes; you can see changes on X-ray and scans and intrinsically you know that pain could result. But how do you strain a rigid joint – so stable that if you are in a dreadful car accident the pelvic bones are more likely to fracture than the SIJ disrupt? Also, despite the book descriptions of how to inject the joint, he was not clear, anatomically, how it was possible to get a needle into it. So if injections seemed to work, how could this be?

So he set up a little experiment. He decided to do a traceable injection. Taking a series of corpses (necessary permissions were obtained) he performed injections by marking out the surface anatomy as per the books, and then injected under X-ray control using Indian ink. Then he dissected down to see where the ink was.

He did not get into a single sacroiliac joint. The ink was everywhere but. Interestingly some got into the venous plexuses and spread up in the vertebral veins but most spread out over the surface of the pelvis under the attachments of the gluteal muscles.

Could it be, therefore, that sacroiliac region pain is actually a gluteal strain syndrome? This little piece of evidence suggests so. If pain is in a particular area that has more than one anatomical structure, you should beware of deciding it comes from one and not another.

You may not be clear if a drug is working…

 …but if you stop it, and everything goes haywire, then you can be sure that it was. This is sometimes the only way to persuade a patient to stay on their pills.

The converse applies. If a patient appears to have side-effects, and you stop it, and everything returns to normal, you can be fairly sure of cause and effect – and make certain by a re-challenge that produces the same problem.  I did this with statins.  More fool I.

You may not be clear if a drug is working (2)…

…and you rely on the evidence as is. However the evidence can change. My biochemistry professor used to say that medical knowledge had a half-life of seven years, so by that time half of what we had been taught might be wrong. Only we don’t know which half.

There are dozens of examples of this with drugs. Take bisphosphonates and osteoporosis. There is no doubt that you can prove that their administration may stop the progression of bone loss. However as time goes by other things surface; thus there has been a significant scare over osteonecrosis of the jaw, and undoubtedly there a many patients who have significant side-effects, either with dreadful indigestion or worse (hence the instruction to wash it down with lots of fluid and then stay upright for half an hour) or acute allergic reactions to the infusions designed to get round this. Just recently reports have appeared of an increased risk of unusual site hip fractures in people on bisphosphonates.[3] So the drug you give causes the very thing you are trying to stop. Not good.  By the same token the elderly patient (more prone to fracture) has been put on blood pressure pills.  So when he or she stands up suddenly they pass out and fall over.  So before starting, ask why (actually with the blood pressure thing you may be risking trouble, as narrower vessels need a higher driving pressure, so you might be at greater risk of a stroke, or coronary, if the pressure drops too far.).  The owner of our local dry cleaners worked that one out so it’s odd that doctors cannot.

[1] For more examples, see Malcolm Kendrick’s “Doctoring data”

[2] Bamji AN, Erhardt CC, Price RP & Williams P. The Painful Shoulder. Can Consultants agree? Brit J. Rheumatol 1996; 35: 1172-74

[3] Agarwal S, Agarwal S, Gupta P, Agarwal PK, Agarwal G, Bansal A. Risk of atypical femoral fracture with long-term use of alendronate (bisphosphonates) : a systemic review of literature. Acta Orthopaedica Belgica 2010; 76 (5): 567-71

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Midwife-led units: safe or silly?

Suppose you are on a flight. The intercom crackles to life and a voice says “Hello! I am Jeremy Corbyn and I am piloting your flight today. I thought you would like to know that I have been fully trained except in the details of what to do if an engine fails or there is a major fuel leak. But I am pleased to say that my senior colleague, who does know how to deal with those, is waiting at the end of a telephone in case of an emergency”.

Would you happily take off? Change the words appropriately and ask yourself whether you would like your sister, wife, daughter to fly in a midwife-led unit.

I thank my good friend, gynaecologist and legal eagle Julian Woolfson, for this parable.

Bare below the elbows: safe or silly?

This is an example of a failure to examine the evidence base.

Many hospitals have imposed a bare below the elbows policy as a result of research showing that cuffs, jewellery, watches and neckties can carry bugs. Bugs can infect patients. Ergo, all of the above, which could cause patients to become infected, must be banned.

When the Department of Health appeared to endorse such a policy (and some Trusts have been quite hysterical in imposing it, with ward sisters screaming at offending staff like little Hitlers). London’s Royal College of Surgeons tried to commission a “for and against” pair of articles. It printed a pair – but both were against, as the journal’s editor was unable to find anyone who would write in favour. The reason was simple. While there is good evidence that ties etc can harbour bugs there is no evidence at all that anyone has been infected thereby[1]. Now I am no Luddite and am the first to remind students about Semmelweis (who? they say) but I cannot endorse a policy for which there is no evidence of benefit and which is founded on myth, supposition and unreasonable extrapolation. I would have conformed when there was some evidence (the Black Swan principle does not pass me by). I used my common sense – something that seem to have been bred out of many in authority – and stripped down appropriately on the ITU and ensured my tie did not dangle in an infected bedsore.

The corollary of this is that if managers insist you conform to a stupid policy then you cannot trust their judgement. People do not have isolated blind spots, and if they cannot take in and understand a scientific analysis of one thing it is almost certain that they will display the same failing in others.

Another infection issue raises the risk versus benefit question. For decades we have used skin prep swabs which come in little paper packets and are very cheap. Suddenly I found that they had disappeared, to be replaced with some fancy ampoules (of three different sizes) which took up cubic feet of storage space and were very fiddly to use (indeed I found it impossible to break the smallest ones without the tube splitting at the back and spreading a slightly tacky antiseptic over my fingers, not to mention driving sharp glass splinters into them). On enquiry I was told that the evidence base for their superiority was unquestionable. However where the old swabs cost about £2.50 per 100 the new ones cost upwards of £30 per 100.

In fact the risk of infection from a no-touch technique joint injection is almost zero, but one feels obliged to spread some sort of muck on the patient just in case, so you can say you have done it. If this new delivery system was to be used in phlebotomy services the NHS would be bust in months.

Actually… in “The Times (9th June 2015) it was reported that some of the damp wipes not only failed to kill the bugs, but spread them about…

[1] This has actually been properly researched. See Willis-Owen CA, Subramanian P, Kumari P, Houlihan-Burne D. Effects of ‘bare below the elbows’ policy on hand contamination of 92 hospital doctors in a district general hospital. Journal of Hospital Infection; 75: 116-119.  Result? BBTE is a waste of time

When researching, look at the original material…

It is a truth universally acknowledged that the British Medical Association vehemently opposed the introduction of the NHS. But it is an untruth. In the mid 1930s it was a BMA committee that produced the first report setting out in detail how a national health service could be provided. The ideas were reworked after the Second World War and many of the key safeguards were lost in the revisions, so the bill presented to Parliament by Aneurin Bevan was criticised for the devil in the new detail. It’s essential to get your historical facts right.

I was once sent a short paper to review; four cases of an unusual problem, reflex sympathetic dystrophy, had followed attacks of shingles. The report stated that this was the first report in the English scientific literature.

RSD seems to be set off by many things. It was first described by a German called Sudek, so I set off to trawl the continental literature. I found a monumental review paper with hundreds of references, from which I uncovered the original paper written by Sudek – in German. Guess what. He had already described his syndrome post-shingles. The moral of this was that the Royal Colleges, in their exams, were perhaps over-hasty in removing French and German from their Membership examinations. Now, of course, almost all the literature is in English, and Google Scholar makes easy work of searching (in the old days we had to plough through huge volumes of “Index Medicus” in the library). So maybe today’s researchers will be more diligent, although one could nit-pick and say that strictly they were right because the paper was not in English. But it is easy to quote references that were quoted by someone else, without checking the original, and mistakes will occur as a result.

There is a postscript to this.  I have been reading Anne Somerset’s book “Unnatural Murder: Poison at the Court of James I (Weidenfeld & Nicolson, 1997).  It has been sitting on my bookshelf unread since I bought it, thinking it looked a ripping yarn, but it has taken me 18 years to get round to it.  Sir Edmund Coke, the Lord Chief Justice, was in charge of investigating the murder of Sir Thomas Overbury.  He was by all accounts a fearsome man.  Somerset writes “He had won his very first case – a libel suit – by catching out the lawyer on the opposing side who had quoted from a faulty English translation of the relevant statute, rather than consulting the original text in Latin.  Though at times ‘so fulsomely pedantic  that a schoolboy would nauseate it’, Coke had gone on to win great renown as a lecturer at one of the Inns of Court, characteristically enjoining his students ‘always to read to the statutes at large and not to trust to the abridgements’.  We are talking about the beginning of the seventeenth century.  Plus ça change…