The Evidence Explosion
When I was young, British TV often showed the old hospital comedies of the 1950s and ‘60s. They were a big hit when Britain still regarded its National Health Service as quite new, the envy of health systems across the world. A perfect setting for hilarious japes, suave doctors and pretty nurses. It was during this time that I first met Sir Lancelot Spratt.
Sir Lancelot was an exaggeration of course, but he embodied everything that was wrong and ever-so-slightly scary about hospitals at the time.
He relied only on his years of experience, and his memories of patients he’d treated in the past, to diagnose and treat people.
Nobody dared question his authority. He knew what was best, and anyone who challenged him would be shouted down. He was Emperor of The Wards.
He relied on the way he’d been taught, so very long ago, even though knowledge and best practice had probably changed. A lot. There were no continuous training programmes in Sir Lancelot’s day.
At one time, the National Health Service was full of Sir Lancelots. In the early 1970s, a man called Archie Cochrane decided he wasn’t very happy with that. Director of the Medical Research Council Epidemiology Research Unit in Cardiff, Cochrane published a book called Effectiveness and Efficiency: Random reflections on Health Services. And in it, he expressed a pretty revolutionary idea:
That what treatments we have available in a health service, the procedures we follow, and the way we treat patients should actually be based on proper evidence that they work, gathered from testing on the wider population.
I know it sounds incredible but that wasn't always the case, even now. In 1990 two researchers made a historical review of the US healthcare system and found that in the 1970s, only around 10-20% of procedures were evidence based. Thankfully by the time of their study the proportion had improved - to 21%.
Archie Cochrane's ideas were developed into a working model by teams in North Carolina and Toronto in the late 1980s and early 1990s. In the present day Evidence Based Medicine is finally standard practise in many international health care systems. But it still has its detractors.
The definition of EBM, in the words of How to Read a Paper author Trish Greenhalgh, is
“the use of mathematical estimates of the risk of benefit and harm, derived from high quality research on population samples, to inform clinical decision making in the diagnosis, investigation or management of individual patients.”
Put that way it sounds a bit dry (though the book is far from it), but it makes sense that the experience of lots of people is going to be more helpful than the personal experience of one doctor, and EBM is about the methods of collecting all that information together, deciding which evidence we should pay the most attention to, then how to use it most effectively in a particular case.
One of those who whipped Cochrane’s ideas into practical shape, Dave Sackett, summarised EBM in five essential steps:
1) We need to turn our problem into a question we can answer
2) We need to track down the best evidence to answer the question with
3) We need to take a look at our evidence to judge a) how close to the truth it is,
b) how it will be useful to our particular problem
4) We need to actually do it
5) We need to evaluate our performance - how well did we do?
We’ll be coming back to look at all these points in more detail in future posts.
The critics of EBM claim it’s little better than a cook book, that it dismisses experience and reduces medicine, and patients along with it, to numbers. But in reality it’s a balance between intuition (experience) and science (trial data).
No doctor could deny that intuition plays a role in their every day treatment decisions, yet surprisingly little research has been done into the way intuition actually works. When you first learn, you stick to the rules. You're worried that if you stray from the path something terrible might happen - and let's be honest, in medicine that's not a bad way for a new doctor to think. But as you gain experience you start to think of your actions in what we call "scripts" - stereotypical case histories where everything goes according to plan and the patient is nice and uncomplicated. Finally, you reach a level of expertise. You collect alternative stories, where the patient was more complicated or the procedure a bit different, either from your own experience or from other people telling you about theirs.
Evidence Based Medicine is still about these scripts and alternative stories - but on a massive, scientifically measured scale. We should never forget that every data point is a person - the woman who found a lump in her breast while trying on a dress in a shop changing room. The man whose wife nagged him to see the doctor when he tried to ignore the blood in his urine. The child who’s needed special care since birth due to the chance, cruel combination of genes. And it’s because it’s people, with loved ones and lives to lead, that we need to use the very best evidence that we can gather.
Yesterday the UK charity Sense About Science launched a new campaign, called Evidence Based Medicine Matters, to give EBM a higher profile in the public imagination. The campaign already has the support of 20 medical Royal Colleges and the Royal Pharmaceutical Society, and yesterday they launched a new booklet at a House Of Lords reception, saying "they will continue to strive towards a solid evidence base for treatments because this gives doctors and patients the best foundation on which to base decisions".
The booklet, launched by Sense About Science in association with the Academy of Medical Royal Colleges, gives 15 shining examples of where Evidence Based Medicine has made a big difference to real people - that woman in the changing room, that man peeing blood. I think Martin Astbury, President of the Royal Pharmaceutical Society, put it best:
"We believe evidence based medicine is the key to the success of modern healthcare. Modern medicine faces challenges every day from therapies that escape rigorous scrutiny: consider the scandal of £4M the NHS spends on homeopathy every year. By continually striving towards a solid evidence base for treatments we give doctors and patients the best foundation on which to base decisions. It is the ongoing process of testing treatments and collecting evidence that moves medicine forward. It is the basis for the extraordinary improvements in life expectancy and quality of life we have seen in the last century."
You might be wondering, if your only experience of healthcare is as a patient, why Evidence Based Medicine should mean something to you. It's quite simple. Firstly you'll benefit from it - you want to know that when you're ill, you're going to have the best and most effective treatment. But also, there's something a bit more subtle to be learned here. How many people, when being diagnosed with an illness, nowadays turn to the Internet? The proliferation of information (and blatant misinformation) is huge. By learning how to gather and weigh evidence as patients, we can make sense of the sheer volume of websites, PDFs and information sources out there. EBM can help us to make sense of our own health.
Evidence matters. Medicine matters. Combining the two can never be less than a good thing. And while the Sir Lancelots can still teach us valuable lessons with their years of experience, they should never be able to overrule the experience of Science.