Education and debate

Barriers and bridges to evidence based clinical practice

Brian Haynes, professor of clinical epidemiology and medicine, ^a Andrew Haines, professor of primary health care. ^b

^a Faculty of Health Sciences, McMaster University, 1200 Main St West, Hamilton, Ontario, Canada L8N 3Z5, ^b Department of Primary Care and Population Sciences, Royal Free and University College London Schools of Medicine, London NW3 2PF

Correspondence to: Professor Haynes bhaynes{at}fhs.mcmaster.ca

Series editors: Andrew Haines and Anna Donald

Clinicians and healthcare planners who want to improve the quality and efficiency of healthcare services will find help in research evidence. This evidence is increasingly accessible through information services that combine high quality evidence with information technology. However, there are several barriers to the successful application of research evidence to health care. We discuss both the prospects for harnessing evidence to improve health care and the problems that readersclinicians, planners, and patientswill need to overcome to enjoy the benefits of research (box).

The aim of evidence based health care is to provide the means by which current best evidence from research can be judiciously and conscientiously applied in the prevention, detection, and care of health disorders.¹ This aim is decidedly ambitious given how slowly important new treatments are disseminated into practice^2-4 and how resistant practitioners are to withdrawing established treatments from practice even once their utility has been disproved.⁵

The barriers to the dissemination and timely application of research findings in the making of decisions about health care are complex and have been little studied. They include many factors beyond the control of the practitioner and patient (such as being in the wrong place when illness occurs) as well as factors that might be modified to advantage (such as doing the wrong thing at the right time). Rather than attempting to dissect all these barriers, we present a simple model of the path (figure) along which evidence might travel to assist practitioners in making timely healthcare decisions. We will consider some barriers along this path and some bridges that are being constructed over the barriers.

	Generating research evidence

The path begins with biomedical research: the shape of the wedge symbolises the process of testing innovations in health care and eliminating those that lack merit (figure). The broad edge of the wedge represents the initial testing of innovations, which usually occurs in laboratories; many new products and processes are discarded early in the testing process. Products or processes with merit then undergo field trials; these initial studies aim to assess toxicity and to estimate efficacy. Many innovations fail, but a few merit more definitive testing in large controlled trials with important clinical endpoints. It is only when studies are successful that serious efforts at dissemination and application are warranted. Increasingly, behavioural interventions, surgical procedures, and alternative approaches to the organisation and delivery of care are being subjected to similarly rigorous evaluation.

The biomedical and applied research enterprise represented by the wedge is vigorous, with an annual investment of over $55bn (£34.4bn) worldwide.⁶ The amount of money spent on research provides hope that healthcare services can be improved despite cutbacks in spending that are occurring in many countries. Unfortunately, many loose connections exist between research efforts and clinical practice, not the least of which is that preliminary studies far outnumber definitive ones, and all compete in the medical literature for the attention of readers.⁷

View larger version (16K): [in this window] [in a new window]   The path from the generation of evidence to the application of evidence

	Steps from research to practice

The boxes to the right of the wedge (figure) represent the three steps that are needed to harness research evidence for healthcare practice. These steps include synthesising the evidence; developing clinical policy from the evidence; and applying the policy at the right place, in the right way, and at the right time. All three steps must be negotiated to form a valid connection between evidence and practice.

Synthesising the evidence
Most results from research appear first in peer reviewed journals, but the small number of clinically important studies are spread thinly through a vast number of publications; readers are bound to be overwhelmed. Models for critically appraising evidence have been developed and disseminated,⁸ but applying these is time consuming. The newest bridges that can be used to overcome this barrier include abstracting services that critically appraise studies in which the results are ready to be applied to clinical settings; these appraisals are then summarised in a journal. ^{9 10} Many more of these new types of journals are being developed so that eventually most clinical specialties will have their own. More importantly, the Cochrane Collaboration has pledged to summarise all randomised controlled trials of healthcare interventions, and The Cochrane Library is now a robust resource.¹¹

Creating evidence based clinical policies
To be both evidence based and clinically useful, clinical policy must balance the strengths and limitations of all relevant research evidence with the practical realities of the healthcare and clinical settings.¹⁴ This is a problematic step because of limitations in both the evidence that is available and in policy making. Clinical practice guidelines developed by national groups may help individual practitioners but the expertise, will, resources, and effort required to ensure that they are scientifically sound as well as clinically helpful are in short supply, as witnessed by the conflicting guidelines issued by various professional bodies.¹⁵ National healthcare policies are often moulded by a range of non-evidence based factors including historical, cultural, and ideological influences. Moreover, when national guidelines or healthcare policies encourage clinicians to perform procedures that are not evidence based, the unnecessary work acts as a barrier to the implementation of other well founded knowledge.

Applying evidence based policy in practice
The next step in getting from research to practice is to apply evidence based policy at the right time, in the right place, and in the right way. Again, there are barriers at the local and individual levels. For example, for thrombolysis for acute myocardial infarction to be delivered within the brief time in which it is effective, the patient must recognise the symptoms, get to the hospital (avoiding a potentially delaying call to the family physician), and be seen right away by a health professional who recognises the problem and initiates treatment. For many people in many places this is still not happening. ^{19 20}

	Making clinical decisions

Once the evidence has been delivered to the practitioner and the practitioner has recalled the evidence correctly and at the right place and time, there are still steps to be taken. Firstly, the practitioner must define each patient's unique circumstances; this includes determining what is wrong with the patient and assessing how it is affecting the patient. For example, the cost effectiveness of lowering cholesterol concentrations with statins is highly dependent on the patient's own risk of adverse outcomes.²⁴ Secondly, the practitioner must then ask if the patient has any other problems that might influence the decision of which treatment is likely to be safe and effective. For example, carotid endarterectomy is highly effective for symptomatic carotid stenosis²⁵ but patients must be physically fit enough to have surgery. Evaluating the patient's clinical circumstances requires clinical expertise, without which no amount of research evidence will suffice.

Also, and increasingly, the patient's preferences, values, and rights are entering into the process of deciding on appropriate management. Thus, patients who are averse to immediate risk or cost may decline surgical procedures, such as endarterectomy, that offer longer term benefits even if they are physically fit to have surgery. Research evidence must be integrated with the patient's clinical circumstances and wishes to derive a meaningful decision about management, a process that no cookbook can describe. Indeed, everyone is still ignorant about the art of clinical practice. Although there is some evidence that exploring patients' experiences of illness may lead to improvements in their outcomes,²⁶ more research is needed into how to improve communication between clinicians and patients if we are to enhance progress in achieving evidence based health care. Additionally, there is a growing body of information available to patients that is both scientifically sound and intelligible, and many consumer and patient groups have made such material widely available.²⁷ Interactive media are being used (but not widely) to provide information to assist patients in making decisions about options for diagnosis and treatment.²⁸

Finally, patients must follow the prescribed treatment plan; increasingly they are doing this independently because of the availability of effective treatments that allow ambulatory, self administered care, and also because of cutbacks in health services that necessitate more self care. We can help patients continue their care, but we are not so successful in helping them to follow our prescriptions closely, which dissipates much of the benefit of treatment.²⁹

	Conclusion

Successfully bridging the barriers between research evidence and clinical decision making will not ensure that patients receive optimal treatment; there are many other factors that might prevail, for example, the underfunding of health services and the maldistribution of resources. Nevertheless, incorporating current best evidence into clinical decision making promises to decrease the traditional delay between the generation of evidence and its application, and to increase the proportion of patients to whom current best treatment is offered. Quick access to accurate summaries of the best evidence is rapidly improving. The means for creating evidence based clinical policy and applying this policy judiciously and conscientiously are under development with help from health services research and information research.

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