Evidence-Based Medicine: A Strange Chimera

Ariane Hanemaayer. The Impossible Clinic: A Critical Sociology of Evidence Based Medicine. Vancouver, Toronto: UBC Press, 2019; 198 pages, hardcover £60.00; ISBN 0774862076

By Sahanika Ratnayake

To begin with a caveat, I am somewhat  unsuitable reviewer for Ariane Hanemaayer’s The Impossible Clinic, a historical and sociological account of the Evidence Based Medicine Movement (EBM). I am an analytic philosopher of science working on contemporary psychotherapies, reviewing a book in sociology. My interest in the book is thus from a cross-disciplinary perspective. What I am unable to offer is something the book thoroughly deserves —  an evaluation on its own terms, as a contribution to the sociological literature on EBM and more broadly, the sociology of medicine and governmentality.

EBM by now is a staple of contemporary medicine, with all manner of fields from psychotherapy and nursing, to new pharmaceuticals and medical technology claiming to be evidence-based. It is a strange chimera, at once an evaluation of interventions, a justification for healthcare policies and a claim to a certain kind of legitimacy. The early development of EBM is similarly multifaceted, with (at least) two main threads, each corresponding to a particular geographic region.

The first concerns the appraisal of evidence for clinical interventions in medical research. Randomised control trials are used to measure the efficacy of clinical interventions and these trials are in turn amalgamated and appraised via systematic reviews and meta-analyses. This thread in the development of EBM, the history of which is still to be written, centers largely on the United Kingdom and involves key developments such as the widely publicised use of a randomised control trial to test the efficacy of streptomycin for tuberculosis, Archie Cochrane’s critique of the prevailing medical research literature and  the resulting establishment of the Cochrane Collaboration in 1993 by Iain Chalmers

The second thread concerns the exercise of clinical judgement. In the late 60’s, medical authority came under scrutiny, as the basis for clinical judgements seemed to be based on nothing more than the authority of practitioners,  resulting in variation across practitioners and interventions that were at best inefficacious and at worst, dangerous for patients.  Championing the need to ground clinical judgement in something other than the intuitions of practitioners, David Sackett and various colleagues such as Brian Hayes and Gordon Guyatt at McMaster University in Ontario, Canada, developed first the application of epidemiological principles to clinical judgements, then a novel program of medical training to improve the ability of clinicians to engage in “critical appraisal” of the research literature, so that the results of research could applied directly to the bedside. Naturally these two threads are intertwined in that moving the ground for clinical judgement away from the authority of individual practitioners and towards evidence, involves an understanding of what constitutes good evidence.

The focus of Hanemaayer’s book is on this second thread. Using a Foucauldian genealogical approach to consider the emerging field of clinical epidemiology, and later EBM at McMaster University, Hanemaayer asserts that “EBM is an impossible project” as it ultimately produces a situation that is antithetical to the original goal of promoting clinical appraisal (p.ix-x).

Chapter 1 provides a background to the critiques, both internal and external to medicine, which brought clinical judgements under scrutiny and demonstrates how clinical epidemiology was developed as a response to these critiques. Chapter 2 considers the various background and institutional forces which supported the development of clinical epidemiology as well as the new training site and program for the McMaster Medical School. Chapter 3 describes the training program and the advent of “Problem Based Learning” which aims to train clinicians who can independently appraise research evidence for use in practice. Chapter 4 describes the creation of Clinical Practice Guidelines, which arose out of a need to summarise the ever-growing research literature and to further standardise clinical decision making. In Chapter 5, Hanemaayer reiterates her central argument: instead of creating clinicians that are capable of exercising their own critical judgement, judgement is instead externalised to Clinical Practice Guidelines. The concluding chapter situates her work within the sociological literature on EBM and studies of governmentality.

There is a desperate need for work such as The Impossible Clinic as the current literature on EBM, tends to focus on the first thread and insofar as there is a history or background to EBM, it is recounted predominantly by those within the discipline such as Sackett.  For instance philosophical work on EBM focuses on the claim to “evidence” and its various shortcomings, as in the work of Nancy Cartwright, Jeremy Howick and Jacob Stegenga. The book’s focus on the training of clinicians and the shaping of clinical judgement provides an opportunity to see the way in which these two threads are linked. For example, flawed as the methods of meta-analysis are, they become somewhat more understandable when we consider the need to summarise a large body of research for use in clinical practice. The main historical account of EBM by Jeanne Daly, draws largely on interviews with key individuals. As such, Hanemaayer’s contribution — focusing as it does on archival research — is a valuable complement to existing work by historians.

The sheer range of archival resources considered in the book — from clinical epidemiology textbooks, private correspondence, policy documents, to records of licensing board hearings — is an impressive accomplishment, presenting a rich picture of the early days of EBM. I was thrilled at the inclusion of building plans for the new medical school, which provide a striking illustration of the adoption of new ideas into medicine through the sharing of physical space with other disciplines (namely, biostatistics and clinical epidemiology), and also the way in which the novel teaching programme was reflected in the new teaching rooms and resources.

I must admit that, in the context of cross-disciplinary interest in EBM, Hanemaayer’s book might be a difficult read. Key players such as Sackett and Guyatt are mentioned or quoted casually early on (p. 4-5) without the usual short description of their importance that typically accompanies first mentions in historical accounts. Those not conversant on the technical details of EBM are also likely to face some confusion with key terms such as ‘randomised controlled trials’ explained cursorily (p.34). More ‘signposting’ and explanation in introducing EBM would have made the book far more accessible for a cross-disciplinary audience. This is perhaps not so much a criticism of the work — as Hanemaayer understandably takes herself to be engaging with extant sociological scholarship and thus assumes a level of familiarity with the area — but rather a caution for others working on EBM, to note that their work will be read with intense interest by those outside their discipline.

I found the central thesis of the book not wholly persuasive, as it suffers from the same issue as Foucauldian genealogical accounts more generally when they attempt to demonstrate an internal tension or failing. In the case of Foucault, whether one thinks the prison apparatus has failed in its goal of punishing humanely and educating prisoners (Discipline and Punish as cited on p.174) depends on whether this was in fact the goal. Similarly, whether EBM has failed in its goal depends on whether fostering critical appraisal in clinicians was the goal.

As Hanemaayer herself notes, “the history of EBM should not be thought about as a linear correction of the problems of clinical judgement” (p. 190). If we take the goal of EBM to be grounding clinical practice in evidence rather than the idiosyncratic views of clinicians or to improve healthcare outcomes for clients it is unclear that EBM has failed.  The studies cited in Howick’s The Philosophy of Evidence Based Medicine (p. 168-176), suggest that EBM recommendations consistently outperform individual clinical judgements. Furthermore, the striking case with which the book opens — the administration of soapy enemas before childbirth — and the lapse in the practice as a result of EBM, invites reflection on whether the situation for clients has improved following the introduction of EBM. That there is a certain irony and tension in the fact that critical appraisal has been replaced by Clinical Practice Guidelines is undeniable, but given the multiple threads to EBM, it is unclear that it has failed outright.

Not only does The Impossible Clinic fill in the gaps of the development of EBM and reorient the tale towards the neglected thread of clinical judgement, itdoes what all good historical investigations, particularly genealogies do — it allows us to look at what has become tacit and familiar with fresh eyes. I read the book as I taught ethics to medical students and found myself understanding certain peculiarities — such as their tendency to tackle normative questions with the same approach that one would use to scrutinise experimental design and the strange fact that a philosopher was teaching them in the first place — which have their roots, at least in part, in the interdisciplinary training program developed at McMaster. 

Sahanika Ratnayake (@SahanikaR) is a PhD candidate at the Faculty of Philosophy at the University of Cambridge. Her PhD project is a philosophical appraisal of Cognitive Behaviour Therapy. She recently received an honourable mention for the 2020 Jaspers Award by the Association for the Advancement of Philosophy and Psychiatry; the paper is entitled, “It’s Been Utility All Along: An Alternate Understanding of Cognitive Behavioural Therapy and The Depressive Realism Hypothesis”. Her previous work on mindfulness can be found at the Journal of Medical Ethics and the online magazine Aeon.