Friday, 20 December 2013

Lessons from history #9: mastectomy

In the early days of surgery, surgeons tried to out do each other in their ability to perform bigger operations, and mastectomy was no exception. For breast cancer, excising the tumour seemed like logical treatment, at least for local control. It also seemed logical that if some excision was good, more excision was better. So simple tumour excision soon gave way to simple mastectomy, which gave way to total mastectomy, which gave way to radical mastectomy, which gave way to things like the ‘extended’ radical mastectomy and the ‘supra-radical’ mastectomy (which included excising the chest wall, amongst other things). Yet, all of this effort was done without properly evaluating the effectiveness – it was all based on what seemed like a good idea.

Friday, 29 November 2013

Book review: The Doctor's Guide to Critical Appraisal

Title: The Doctor’s Guide to Critical Appraisal, 3rd Ed (2012)
Authors: Narinder Gossall, Gurpal Gossall
Publisher: PasTest

This book is not an opinion piece and it holds no new information, but it is as important as any other book I have reviewed because it aims to narrow the gap between practice and evidence in medicine by teaching doctors the science of medical practice; in other words, how to recognise and weigh error, and objectively appraise the scientific evidence for clinical practice.

Monday, 18 November 2013

The map is not the territory

Another version of this saying is “Treat the patient, not the X-rays”, but try as we might, we still end up treating the X-rays, even when the evidence is to the contrary.

Sunday, 10 November 2013

Clot filters

It seems I will never run out of examples of treatments that sound obviously effective in theory, fall into common use based on the strength of the biological mechanism, and yet they fail to show a significant benefit when put to the test. The story of the IVC filter is one of these.

Deep venous thrombosis (DVTs, clots) in the leg can dislodge, traveling up through the main vein in the pelvis and abdomen (inferior vena cava, IVC), through the heart and then embolise in the lungs (pulmonary embolus, PE), sometimes causing rapid death. An IVC filter is a wire cage placed in the IVC that snares clots that have broken free from the leg veins, before they can travel to the lungs. The device has been used for decades, but without much evidence of benefit, as this recent report tells us.

Thursday, 31 October 2013

Osteoporosis drugs – cosmetic surgery for the bones?

One of the most popular drugs prescribed these days are the bisphosphonates. You may know them as Fosamax (alendronate) or Actonel (risendronate). They have been pitched as the drug that everyone with osteoporosis should take, and if you are a female over 50, you may have been advised to get your bone density measured, in case you need to take these drugs. Worldwide sales of Fosamax alone hit the $3 billion mark before it went off patent in 2008. We know the drugs increase bone density, but that is just cosmetic surgery for the bones. How much of that translates into fracture prevention? And how many people would want to take this drug if they were given an accurate description of the risks and benefits?

Friday, 11 October 2013

The magical “floating” kidney

I started writing this up as a “Lesson from History”, because floating kidney (or “nephroptosis”) was big in the late 19th century, and I thought that the condition was no longer taken seriously. In researching this however, I found that surgery for this condition is having a resurgence thanks to laparoscopic (keyhole) surgery. To a man with a hammer, everything looks like a nail.

Monday, 7 October 2013

Book review: The Role of Medicine: Dream, Mirage or Nemesis?

Title: The Role of Medicine: Dream, Mirage or Nemesis? (1979)
Author: Thomas McKeown
Publisher: Basil Blackwell, Oxford

In a book that is often grouped with Effectiveness and Efficiency (Cochrane) and Limits to Medicine (Illich), Dr McKeown attempts to calculate the role of medicine in the improvement in health seen over the preceding centuries. He also points out the current problems with medicine (in the 1970s, anyway) and makes suggestions for the future of medical practice, education and research.  Fortunately, many of his suggestions have been realised, but unfortunately, the contribution of medicine to the continuing improvement in health remains overestimated.

Friday, 20 September 2013

Why does spine surgery increase impairment?

In the world of compensation and impairment ratings there is a bible known as the AMA Guides to the Evaluation of Permanent Impairment. The “Guides” aren’t perfect, but I have one major criticism: that the impairment rating for spinal conditions is linked to having surgery, such that surgery (that is undertaken in order to reduce impairment) increases the impairment rating. I will take you through the twisted logic, but it makes as much sense as awarding no impairment for someone crippled with knee arthritis, and then awarding a high impairment rating after they have had their knee replaced and their function restored. This paradox is helping surgeons and lawyers, but does little for the patients except to increase their payout.

Tuesday, 10 September 2013

Craniectomy – a no-brainer?

Raised pressure in and around the brain is associated with (notice I didn’t say “causes”) bad outcomes in patients with traumatic brain injury. Management of such patients centres around reducing this pressure, either by managing their breathing and giving drugs, or by surgical decompression of the brain, usually achieved by removing a piece of skull (craniectomy). Craniectomy is common practice, and it has been around for over 100 years. This recent comparative trial showed that craniectomy was successful in reducing the pressure around the brain, but caused (notice how I didn’t say “was associated with”) more harm than good. A case of “the operation was a success, but the patient died”.

Saturday, 31 August 2013

Calcium for healthy bones?

It’s one thing when my patients tell me that they are eating extra calcium to help their fractures heal or prevent new ones, but when my colleagues are advising them the same thing, its time to correct the bias. Taking calcium and/or vitamin D to heal fractures and prevent new fractures is another case of something that sounds good and is easy to believe, but doesn’t work as advertised.

Monday, 19 August 2013

Hiding in the herd

I had a conflict of interest while operating the other day. I had a patient with a hip fracture that needed surgery, and a knee fracture (on the same side) that would normally be fixed surgically but according to my criteria (decent evidence), it wasn’t necessary. I would not have been criticised for doing the surgery (in fact, my trainees had already consented the patient, thinking that I would). Further, I expected some criticism for not doing the surgery, and I would have felt terrible if the result of my non-operative treatment had been poor. The conflict? I would have been paid a lot of money to do the surgery, and got paid nothing for treating it non-operatively. I was tempted to hide in the herd.

Sunday, 28 July 2013

Book review: Thinking, Fast and Slow

Title: Thinking, Fast and Slow (2011)
Author: Daniel Kahneman
Publisher: Penguin Books

This book gives us insight into how our brains work. How they are hard-wired for shortcuts that require the near-instantaneous processing of a large amount of information. Often these ‘decisions’ (more like reactions) are right, but they can also be wrong, and the biases that are inherent in our decision making and our memories often give us a perception that does not match reality.

Sunday, 16 June 2013

Book review: The Great Cholesterol Myth

Title: The Great Cholesterol Myth (2012)
Authors: Jonny Bowden and Stephen Sinatra
Publisher: Fair Winds Press

There is nothing I like more than finding out that something that has been widely believed for decades is wrong. The cholesterol myth fits the pattern of so many items in my blog: it sounds good, it superficially makes sense, and there is a biologically plausible explanation, but when put to the (scientific) test, it fails.

Saturday, 8 June 2013

Unintended consequences and the homeostasis of risk

I recently saw a patient who broke her ankle slipping on the shiny yellow paint they use to highlight the edges of steps. Is this an example of the law of unintended consequences, or the theory of risk homeostasis (risk compensation)? Either way, a well-intended intervention backfired (what the CIA colourfully label ‘blowback’), a phenomenon more common than we think.

Thursday, 6 June 2013

Web review: Skeptical Medicine

Skeptical Medicine is a website, not a blog, and I highly recommend it. It contains material from a single author, covering topics related to the scientific basis of medicine: reason, logic, argument, bias, and the philosophy of science. It is extremely well written and referenced but most importantly, it is reasoned, logical and, well, very scientific. For anyone wondering what it is to be skeptical – to take a scientific view of any subject (not just medicine) – then this is the site to read.

Sunday, 26 May 2013

Lessons from history #7: medically induced thyroid cancers

In the 1940s to 1960s, children with an upper respiratory illness were often thought to have an enlarged thymus gland (in the neck), and were given some radiation therapy to settle it down. The thymus shrank after being irradiated and the kids generally got better, so the practice continued. It didn't matter that this was not a real disease, or that the treatment was not appropriate, or that the kids would have improved anyway; doctors did something and the patients got better. That, and some cockamamie biological explanation, was all the doctors needed. Well, that and some insurance to cover the medical costs of the kids who got cancer as a result of the radiation.

Friday, 10 May 2013

Is medical practice running ahead of the evidence?

Recently, while debating a respected colleague regarding a shift in practice towards treatment X, despite a lack of evidence showing its superiority, my colleague said: “But we know that practice always runs ahead of the evidence”. He was implying that the evidence would one day catch up and justify the practice. I wondered if medical practice really was running ahead of the evidence, or whether it was running away from it.

When clinical practice does run away from the evidence, we tend to spend our time gathering evidence to support the current practice, instead of using an objective evaluation of the current evidence to inform future practice. This is known as putting the cart before the horse. It is also known as Confirmation Bias.

Friday, 19 April 2013

Tennis elbow treatment: perception versus reality

For decades, surgeons have been reporting good results with surgery for tennis elbow. In a classic article from 1961, the late, great British surgeon RS Garden, reported that the results of surgery for tennis elbow were such that “no patient failed to benefit in some way from the operation”. Fifty years later in a review of 80 patients undergoing surgery for tennis elbow, 78 were reported to have improved. There are plenty of non-surgical treatments out there for tennis elbow (lateral epicondylitis) - all of them are reported as having good results, yet none of them are any better than placebo. Why then, did it take until now for a randomised trial to be done comparing real surgery with sham surgery?

Sunday, 14 April 2013

Book Review: The Truth About Drug Companies

Title: The truth about drug companies: how they deceive us and what to do about it (2004)
Author: Marcia Angell
Publisher: Random House, New York

Marcia Angell was an editor for a leading medical journal (the New England Journal of Medicine) from 1979 to 2000, and she is an outspoken critic of big pharma. In this book, she spells out why, and makes a compelling case for being sceptical about the medical information we receive, whether it be from journals, companies, doctors or interest groups. The extent to which that information is biased towards pharmaceutical companies (and their products) remains underestimated.

Sunday, 7 April 2013

Trends, forests and trees

How many times have you seen the results of a new way of doing things, where the results after the introduction were shown to be better than they were before? These ‘before-and-after’ studies almost always show an improvement, but does that mean that the improvement was caused by the intervention? Given the example I will show you below, you should conclude that our highly evolved tendency to read cause-and-effect into any association often runs counter to reality.

Friday, 5 April 2013

Book review: The wisdom of the body

Title: The wisdom of the body (1932, 1939)
Author: Walter B Cannon
Publisher: W.W. Norton & Company, New York

This book is old, but its subject and its message still hold. The book is about homeostasis: how the body adapts to keep things in equilibrium, despite forces that attempt to change the balance. This provides an important lesson to those who attempt to influence the balance of anything in the human body: the body will adapt, making the intervention less effective. A lesson that many do not learn.

Wednesday, 27 March 2013

Book review: Meaning, Medicine and the Placebo Effect

Title: Meaning, Medicine and the Placebo Effect (2002)
Author: Daniel Moerman
Publisher: Cambridge University Press

In this book, an anthropologist offers an outsider’s view of medicine. The book is not restricted to an examination of the placebo effect (in fact, the author suggests abandoning the term, instead using “meaning response”); it asks readers to see all of medicine (and indeed biology) in its social and cultural context. The author shows that much of what we “know” isn’t necessarily true (or more confusingly, that it might be true in certain contexts). In that vein, he criticises doctors for dressing in science (empirical evidence), but practicing experiential evidence, and therefore not being able to see that what they “know” (based on tradition and their own experience) might not be true (despite being able to construct biological mechanisms to explain the perceived effect).

Tuesday, 19 March 2013

Lessons from history #6: The Vioxx saga

The Vioxx saga contains everything: conflicts of interest, big pharma influence, dodgy government regulators, data fabrication, and a body count. But there is more to the story: it is an example of a common logical fallacy whereby, when faced with a study that shows treatment A to be better than treatment B, we assume that treatment A is providing a benefit, and not that treatment B is harmful. Both assumptions may be equally valid, but we tend to choose the former. Had we not done so in this case, Vioxx might not have harmed so many people.

Sunday, 10 March 2013

Book review: Rethinking Aging: Growing Old and Living Well in an Overtreated Society

Title: Rethinking Aging: Growing Old and Living Well in an Overtreated Society (2011)
Author: Nortin M Hadler
Publisher: University of North Carolina Press, Chapel Hill

In his latest offering, Dr Hadler rehashes and updates many of his familiar arguments (breast and prostate screening, cardiac stents, osteoporosis, antidepressants, back surgery), this time applying them to the elderly. He adds material specifically about growing frail and dying, and as usual, he provides considerate, accurate, useful and often counter-intuitive information for the would-be health care consumer.

Sunday, 24 February 2013

Keeping childbirth normal

The variation in cesarean section operation (C-section) rates during childbirth is well documented; between hospitals, states and countries. The rates also vary over time, but here the pattern is at least consistent: the rate is increasing. So what? Sure there are complications, but isn’t that worth it if we are saving lives? As usual, it turns out that we have been overestimating the benefits and underestimating the harms of C-sections, which may explain the overuse of this treatment.

Wednesday, 13 February 2013

The antioxidant myth

A recent Scientific American article challenges the myth of antioxidants being associated with ageing. This is not the first time SciAm has covered this topic (here, here and here). The article challenges current perceived wisdom, not only regarding the effectiveness of anti-oxidants but of the underlying theory that oxidative damage causes ageing.  The current evidence tells us that antioxidant supplementation is not only ineffective, it is harmful. The sorry story of antioxidants should really be one of my “Lessons from History” blogs, except that it has not yet been relegated to history. But the story still provides lessons.

Sunday, 10 February 2013

Ethical double standards

Ethics committees (IRBs in the US) are now firmly entrenched in the research environment such that clinical research can only be performed with their approval. Clinical practice, however, is not subject to such approval, yet in many cases the risk of harm (individually and to society) from clinical practice is greater. Are researchers being held to a higher standard than clinicians? Has our concentration on ethical standards for clinical research led to an ethical blind spot for clinical practice?

Sunday, 27 January 2013

Don’t just do something, stand there

This reversal of a commonly used phrase is a plea. A plea against the bias that leans doctors towards diagnosing and treating, even when the scientific evidence may not support it. Sure, it is expected that a doctor will diagnose and treat you, but sometimes there is no diagnosis or effective treatment, and pursuing either may be harmful. When in doubt, your doctor will continue to run tests until something comes up, and will continue to treat you for as long as you return with symptoms. Sometimes, not pursuing a diagnosis and not treating a patient are reasonable options. Sometimes they are the best option.

Friday, 18 January 2013

Book review: Limits to Medicine

Title: Limits to Medicine. Medical Nemesis: The Expropriation of Health (1975)
Author: Ivan Illich
Publisher: Marion Boyars

Ivan Illich was a philosopher and historian who published several books in the 1970s targeting areas like medicine, transport, education and energy use. His thesis was that modern, western, industrialisation and in particular the institutionalization of specialised knowledge by the professions has far-reaching negative consequences. His 1975 book Limits to Medicine. Medical Nemesis: The Expropriation of Health made his case against modern, institutionalised medicine. He felt that more expensive and specialised medicine was more likely to be harmful and less effective, and that important aspects of the life experience such as birth, mating, suffering, aging and dying were being medicalized. His points were interesting and controversial in their time, and the following 40-odd years of growth in specialised industrial medicine has made many of them prescient.

Sunday, 6 January 2013

Lessons from history #5: Bone marrow transplant for breast cancer

In the 1990s, giving patients with breast cancer massive doses of chemotherapy or radiotherapy followed by a bone marrow “rescue” was thought to improve survival and even cure the disease. It was complex, expensive and risky, which only raised the perceived effectiveness. The treatment spread, and insurance companies had to fall in line to cover the treatment due to legal, government and public pressure. The randomised trials that were eventually done showed that it was no more effective than standard treatment. Here is the story and the lessons that can be learned.

Saturday, 5 January 2013

Evidence based medicine vs the Golden Rule

I am a big fan of evidence based medicine (EBM). Not the cookbook type (“do it this way or else”), but the idea that medicine is a science and therefore should be approached scientifically. We should use the principles of logic and rational thinking to reduce the errors that result from our often irrational, subjective “human” way of making decisions. Sometimes, however, we try to use EBM to justify something that doesn’t need scientific support – something that should be the default, and only changed if there is evidence against it. Something like the Golden Rule.

Tuesday, 1 January 2013

What's the deal with those bad hip replacements?

Most people are aware that a year or two ago there were some new hip replacements that were recalled. The story behind it has all the ingredients to suit this blog: overestimation of benefit, underestimation of harm, regulation failure, and conflict of interest up the wazoo. The ‘deal’ as it were, was a bad one for patients, a bad one for the company (in the end), but a great one for the surgeons, as it became the gift that keeps giving.