What's the evidence?

With just the click of a mouse, you can access thousands of research articles of variable credibility about lots of different medical conditions. But how do you actually apply them to clinical practice? Manique Wijesinghe and Sharon Strauss describe how you should use evidence based medicine

Practising evidence based medicine (EBM) is one way for medics to keep abreast of the clinical literature. The term EBM was coined about 10 years ago, but its origins date even earlier. EBM refers to “the judicious application of best current knowledge to the condition and values of the individual patient.”¹

Teaching EBM and integrating it into routine clinical practice

Medical students and doctors need critical appraisal skills to make sense of the overwhelming volume of information available. A study in the BMJ showed that teaching these skills so that they are integrated into clinical practice has greater benefits than traditional methods such as workshops and standalone courses.²

Since 1997, the Hospital for Tropical Diseases in London has been holding regular meetings at which the evidence about a particular clinical problem is reviewed. When the reviewers believe that that research supports it, they change existing treatment plans.³ This approach stresses the practical clinical application of evidence.

Evidence often not used in clinical practice

The United Kingdom’s National Institute for Clinical Excellence (NICE) issues evidence based guidelines for use by clinicians in hospital and primary care environments.⁴ A study in the BMJ shows that implementation of NICE guidelines is variable.⁴ Guidance is more likely to be adopted when professional support is strong, the evidence base stable and convincing, and no increased or unfunded costs are incurred. A study carried out in a primary care setting⁵ found that doctors tended to rely on collectively reinforced, internalised, tacit guidelines being used by respected colleagues, and that they rarely used explicit evidence (such as research articles).

Potential risks of using EBM

Hilda Bastian, a researcher based in Germany, writes that jumping to conclusions too can lead to inappropriate decisions, for example relying on a systematic review that doesn’t provide sufficient information about the adverse events of an intervention.⁶ “A promising treatment is just the larval stage of a disappointing one,” she opines. She adds, “Sometimes it [EBM] causes harm, especially when people react every time that individual trial results become available.” For example, in 2001, a study found that neck collars should not be given to those people with whiplash injuries. In 2003, this finding was reversed when data from more trials became available. Bastian points out that overly hasty implementation of research findings, without careful consideration of its validity, may place patients at risk. Clinicians need to be educated about both primary articles and systematic reviews.

Legal implications for practitioners of EBM

Using evidence based guidelines issued by organisations such as NICE has medicolegal implications. Should a doctor who does not follow such guidelines be found guilty of medical negligence? Guidelines are formulated with a general case scenario in mind; doctors, on the other hand, deal with individual patients. Following evidence based guidelines may therefore generally, but not always, assure good medical care, and diverging from guidelines does not always signal poor care.⁷ Although evidence based guidelines do set normative standards, they do not constitute a de facto legal standard of care.⁸ As clinicians we must consider each patient individually and ensure that we provide him or her with the best available evidence with which to reach a decision.

The patient’s perspective

Today’s patients are clued up. Many have access to the internet, where they are exposed to information about their conditions, most of which is of dubious value. Many patients also want to be involved in deciding what treatment they receive. It is therefore not enough to simply carry out an evaluation of the “best available evidence” and apply it to your patient; he or she may refuse that treatment because it does not fit with their values and circumstances. Medicine is not just a science. Patients are not skin covered bags of chemicals; they are complex individuals with widely differing feelings, beliefs, fears, and opinions. Patients’ values are the unique preferences, concerns, and expectations that each patient brings to a clinical encounter, which must be integrated into clinical practice if they are to serve the patient.⁹

TOPFOTO

"It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts" - Sherlock Holmes

Susan Lockwood, a patients’ advocate, says: “There is a stark difference between the empirical basis of evidence based medicine and the value systems of individual patients.”¹⁰ One person she interviewed in her study said that the information given to her by doctors was not very helpful, “probably because they talk in general terms. They are talking about groups of people rather than individuals. And because they’ve had no experience of illness, they don’t really understand what you’re looking for in terms of information—as to how it affects you personally.”

Doctors need to listen to their patients and discuss their concerns with them. Telling someone who’s just received a diagnosis of a serious illness that he or she could reduce his or her chances of dying to just 1 in 200 by using drug X is meaningless and insensitive, even if it is true. Information needs to be given to patients in a such way that they can make sense of it, and they need to feel that any advice that they are given applies to them personally. Myriam Hunink, a professor of clinical epidemiology and radiology in the Netherlands, writes: “Focusing too much on the rational and quantitative aspects of clinical problems—an inherent danger in EBM—can have a negative influence on the doctor-patient relationship … We also need to integrate the evidence with patients’ values and preferences.”¹¹

EBM around the world

EBM is increasingly seen as essential to good medical practice. In middle and low income countries, centralised organisations—such as the World Health Organization—and national health ministries have a crucial role in ensuring the application of the best available knowledge.¹²

Michael Lowe, a Fiji based doctor, writes: “Evidence based medicine—where the term is used in the more formal sense—has unfortunately only limited applicability in Fiji and the less developed world in general.”¹³ A major reason is the expense: buying and maintaining computers with internet access and the high subscription costs to access the articles. He also says that often, studies carried out in the West have limited applicability in the developing world. “Because doctors must base their diagnoses and treatment on such resources, they need to think creatively, instead of relying on the latest review in a specialist journal.”¹⁴ Perhaps more importantly, 10% of funded research addresses issues affecting 90% of the world’s population—most studies do not consider the relevance of their findings to developing countries.

Hospitals in the developing world have a lack of resources—for example, sophisticated diagnostic tests. But this lack of resources “must not be seen as a reason for not attempting to make care more evidence based.”¹³ Ways and means to overcome the financial constraints can be found with a little ingenuity, and the ultimate benefits may outweigh the initial costs in the long term.

Ultimately EBM requires a mix of the best available evidence, clinical expertise, and a patient’s values and circumstances. Robotic adherence to guidelines or research findings should not be the goal of even the most ardent EBM enthusiast. Each patient, caregiver, and their particular circumstances have distinct differences, and the guidelines may not be applicable in the same way. EBM is a valuable, perhaps indispensable, tool for today’s busy clinicians, but it is a tool that should not be wielded blindly or indiscriminately. Doing so would ignore the true definition of EBM and rob the art of practising medicine of its very essence.

Sharon E Strauss, associate professor, Department of Medicine, University of Toronto, Canada

Manique Wijesinghe, second year medical student, University of Southampton
Email: manique_w@hotmail.com


studentBMJ 2005;13:89-132 March ISSN 0966-6494

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