Skip to content

You are reading 1 of 2 free-access articles allowed for 30 days

Ignoring the evidence

At the Los Angeles premiere of his film City Lights (1931) Charlie Chaplin told his guest Albert Einstein: “They cheer me because they all understand me and they cheer you because no-one understands you.” So when scientist and novelist CP Snow delivered his 1959 Rede Lecture at Cambridge University on ‘The Two Cultures and the Scientific Revolution,’ his reference to the “gulf of mutual incomprehension” between scientists and what he called “traditional culture” was hardly ground-breaking.

Chaplin and Snow identified a difference between artistic and scientific knowledge, but a variation of Snow’s two cultures is developing within medicine between those who favour evidence-based medicine (EBM) and those who don’t.

Since the publication of Guyatt et al’s ‘Evidence-based medicine, a new approach to teaching the practice of medicine’ in JAMA (1992; 268: 2420−2425), EBM has risen to the extent that its tenets – you know what they are – underpin medicine’s present-day rationale. Yes, the inky Clinicians for the Restoration of Autonomous Practice (CRAP) launched a mischievous raid on the altar of the randomised controlled trial (RCT) in a partly tongue-in-cheek article for the BMJ (2002; 325: 1496-8) – “Thou shalt treat all patients according to the EBM cookbook, without concern for local circumstances, patients’ preferences, or clinical judgment” – but generally the ideology of EBM is embraced by the medical profession… isn’t it?

Not entirely, based on a peek in the Irish Journal of Medical Science. First, Silvio and Cronin (2016, 185: Suppl.2 S128), describing ‘Neglected gallbladder disease in Ireland’ note: “Irish hospitals continue to ignore the evidence-based medicine regarding the recommendation to perform cholecystectomy in acute cholecystitis, adding to patient morbidity, mortality, and economic burden of our health service.”

Second, Moriarty et al (2014, 183: Suppl.1 S40) systematically reviewed studies on the treatment of slipped capital femoral epiphysis (SCFE), concluding that “[t]he majority of therapeutic studies on SCFE are of low level of evidence”.

Third, and most recently, Ramasubbu et al described ‘A study to investigate the factors that influence the prescribing habits of non-consultant hospital doctors in Ireland’. From 179 surveys returned from a possible 8,987 they found that “[c]onsultant preference was the biggest overall influencing factor on junior doctors prescribing (27 per cent)”, with local departmental policies accounting for 26 per cent. Pharmaceutical reps’ wily deployment of dinky pens and fancy mouse mats helped influence 13 per cent of NCHDs in their prescribing, but – and at least one reader senses exasperation when the authors report – “[i]ncredibly this was only 1 per cent less than evidence-based prescribing”. In the context of the authors citing HSE expenditure of €2 billion on medicines in 2013, to learn that only 14 per cent of NCHDs relied on EBM to determine their prescribing choices invites the inference that many medics give scant regard to EBM.

Is this reluctance to cleave to EBM’s ideology a retrograde step? Perhaps not. When Rogers considered ‘Evidence-based medicine and justice: A framework for looking at the impact of EBM upon vulnerable or disadvantaged groups’ in the Journal of Medical Ethics (2004, 30: 141-145), he highlighted the importance of justice in healthcare and the lack of a logical relationship between the proof of effectiveness of a treatment and the importance of the condition for which the intervention is effective. So, instead of first establishing priorities and performing research to determine how to meet agreed ends, EBM inverts the system: “The research is performed, often for largely commercial reasons, and then the presence of this evidence is taken as some kind of imperative.”

In the same issue of the same journal (pp. 160−165) Stirrat contemplates ‘Ethics and evidence-based surgery’, and is certain that while EBM confers a net benefit, “over reliance on randomised controlled trials and the lack of generalisability of scientific evidence to individual patients has perhaps led to less enthusiasm for its tenets among surgeons”.

From time to time in the Irish medical press I’ve seen quoted “You are entitled to your opinion, but you are not entitled to your own facts,” and always without acknowledging American Democratic Senator Daniel Patrick Moynihan (1927-2003) as the (likely) original source. But the Senator was wrong. In a democratic society one is of course entitled to one’s own facts. I’m free to argue that black is white; but the point is that if I’m unable to prove it then others are free to draw their own conclusions in loud and embarrassing ways.

I raise this because in the EBM context, its ardent supporters assert that meaningful medical-scientific facts can only be reliably viewed and appraised through the prism of the RCT. This relegates the importance of cultural and other factors, which influence the way we think, so that a fact asserted by a physician that he/she has acquired through experience-mediated knowledge or the careful sifting of opinion is deemed inadmissible.

But as philosopher Mary Midgley warned in her ‘Science as Salvation: A modern myth and its meaning’ (1992): “Views about facts never stand alone. They are always shaped by background world-pictures … these world-pictures are themselves not value-free ….”

Finally, EBM ideologues might reflect on what Clive James wrote in Cultural Amnesia (2007) when discussing totalitarianism: “… what else was an ideology except a premature synthesis?”

  1. Donncha O'Gradaigh on October 13, 2016 at 2:53 pm

    It must be Autumn, the season for old chestnuts… I have spent two years in the company of the “ardent supporters” referred to by George Winters, completing a Masters in Evidence-Based healthcare in Oxford. The attitude there is refreshingly honest, as attested to by Trish Greenhalgh in an important essay (BMJ 2014;348:g3725).
    EBM is fundamentally about ensuring patients benefit from what is known and are not subject to experimentation by practitioners who rely on personal preferences instead of the information gathered from others’ sacrifices (as placebo-taking RCT participants), adverse experience (outcomes of exposure in observational studies) or anxious waits for further tests (diagnostic studies). It is true that pharmaceutical research can inflate the importance of effects on secondary or surrogate outcomes they choose to report – that is why a key tenet of evidence-based practice is to search for evidence which addresses the clinical problem. The mantra of EBM is not blind obedience, it is not to search for patients to whom the evidence can be applied, it is not to refuse to care for those whose clinical problem has not been addressed by research. It is to find, critically appraise and offer to the patient to best available information, integrated with honest reflection of personal experience.
    Take a look at the next five clinical decisions you make. If there is evidence to support them, you are “an ardent supporter”, wherever you picked up the habit. If alternative approaches are favoured, there lies the ethical issue. If there is no evidence, at the very least there is an opportunity to add to the body of knowledge with the agreement of an informed patient and within a properly designed study. Various bodies already recognise that such uncertainties exist (see James Lind Alliance). And beyond our individual practice, we must go on to ensure that the culture of EBM pervades decision-making throughout the healthcare structures looking after our patients.

Leave a Comment

You must be logged in to post a comment.

Scroll To Top