A reality check for systematic reviewers
Sir Iain Chalmers is one of the founding members of The Cochrane Collaboration. Since his retirement as Director of the UK Cochrane Centre in 2003, he has worked with the James Lind Alliance, based in Oxford, UK, which focuses on bringing patients, carers and clinicians together to identify and prioritise unanswered questions for directing healthcare research. Here he discusses a new book by doctor and journalist Margaret McCartney, particularly the issues it raises about using systematic review evidence in clinical practice.
Cross-posted from the Cochrane Editorial Unit Blog.
Margaret McCartney is a general practitioner and award-winning journalist. Some readers will be familiar with the regular column that she was commissioned to write for the Financial Times (archived here); many people will know her as a frequent contributor to the BMJ.
Margaret McCartney’s writings are appealing. This is not only because she is an excellent writer, but also because they mix insufficiently uttered common sense with iconoclasm and challenges to mainstream thinking. Her recently published book - The Patient Paradox: why sexed up medicine is bad for your health (Pinter and Martin, 2012) – is packed with these things.
The 'patient paradox' in the title of the book refers to the way that political, professional and commercial promotion of screening and testing have become so pervasive that normal people are being converted into patients, and that, partly as a consequence of unwarranted diversion of limited resources to fuel this trend, many real patients in need of effective professional help are losing out. The inexorable conversion of people into patients has been achieved by exaggerating the chances of important health problems developing in symptomless people (for example, by citing relative rather than absolute risks), while ignoring or downplaying the adverse psychological and sometimes physical effects of the process of ‘patient creation’.
Although these are issues that Margaret McCartney and others have raised previously, her book is particularly important for people unfamiliar with the challenges resulting from these trends for doctors working in general practice. She spells out the real consequences of these trends on the use of her time as a general practitioner. Instead of using most of the limited time she has to listen to and to try to respond effectively to the variety of concerns that ‘real’ patients bring to her, that objective has to compete with politically imposed general risk assessment activities and the need to reassure poorly informed well people who have been worried unnecessarily.
Margaret McCartney’s testimony and insights as a general practitioner are also the reason that I think the book provides ‘a reality check for systematic reviewers’. A middle section of her book begins with a chapter entitled 'George Clooney and the medical certainty illusion'. This chapter contains subsections entitled 'It’s all (at least) a little bit uncertain', 'Bayes, balance and humanism', and 'Binary medicine'. Although Margaret McCartney leaves her readers in no doubt about the need to take account of systematic reviews when considering how to help patients, she illustrates how complex a process this can be for general practitioners trying to take account of the varying characteristics and needs of individual patients.
These reflections will confirm what many – perhaps most – of Margaret MacCartney’s clinician readers know already; but then her book is not aimed principally at them, but at the general public. However, the book should help people preparing and publishing systematic reviews who remain insufficiently familiar with the realities of clinical care. It illustrates how the process of using the important evidence they are producing to inform decisions in health care is often far from straightforward.
This reality was reflected in the brochures and articles introducing the first Cochrane Centre and The Cochrane Collaboration. These made clear that systematic reviews are essential, but not sufficient for informing decisions in health care. Needs, resources and priorities also have to be taken into account. I have sometimes been left with the impression that these complexities have been insufficiently appreciated by those unfamiliar with the realities of clinical care.
It comes as a surprise to many people that I have never accepted invitations to speak or write on the topic of ‘evidence-based medicine’. As a clinician who has not practised clinically since 1973, I don’t think my opinions on this important topic should have any credibility. One of the characteristics of experienced and effective clinicians is that they draw on wisdom to judge how best to use reliable research evidence in the service of their patients. Ben Djulbegovic and Paul Ash have suggested that "Wisdom is the ability to distinguish between reducible and irreducible uncertainty". On the basis of what she has written, Margaret McCartney is a wise clinician who helps us to appreciate what this means in practice. If I lived in Glasgow, I hope she would accept me as her patient.