Health information for the clinician

About evidence based medicine

What is EBM?

Evidence Based Medicine is an approach to forming medical knowledge, based on systematic and unbiased methods of appraising scientific evidence (Source: BestBETs website).

What is Evidence-Based Health Information – an overview of Evidence-Based Medicine from The Joanna Briggs Institute

What is Evidence-Based Medicine – a clearly written PDF Publication taken from the What is…? Series. (Source: Hayward Medical Communications, May 2009)

The Key Steps in Evidence Based Practice (EBP)

Evidence-based practice (EBP) is the inclusive term which the principles of EBM are founded; primarily EBP is based on five well defined steps.

Step One: Asking Focused Questions: translation of uncertainty to an answerable question

Step Two: Finding the Evidence: systematic retrieval of best evidence available

Step Three: Critical Appraisal: testing evidence for validity, clinical relevance, and applicability

Step Four: Applying the Evidence: application of results in practice

Step Five: Evaluating Performance: auditing evidence-based decisions

The five steps of EBP – information on the five steps from the Centre for Evidence Based Medicine website

Step One: Asking Focused Questions

To benefit patients and clinicians, well built and focused questions need to be both directly relevant to patients' problems and also directs your search to relevant and precise answers. In practice, well-built clinical questions usually contain the four PICO elements (Source: Centre for Evidence Based Medicine).

P - Patient, Population, or Problem How would you describe a group of patients similar to yours? What are the most important characteristics of the patient? This may include the primary problem, disease, or co-existing conditions. Sometimes the sex, age, or ethnicity of a patient might be relevant to their diagnosis or treatment.

I - Intervention, Prognostic Factor, or Exposure Which main intervention, prognostic factor, or exposure are you considering? What do you want to do for the patient? Prescribe a drug? Order a test? Order surgery? What factors may influence the prognosis of the patient? Age? Co-existing problems? What was the patient exposed to? Asbestos? Cigarette Smoke?

C - Comparison of Intervention (if appropriate) What is the main alternative to compare with the intervention? Are you trying to decide between two drugs, a drug and no medication or placebo, or two diagnostic tests? Your clinical question may not always have a specific comparison.

O - Outcome you would like to measure or achieve What can you hope to accomplish, measure, improve or affect? What are you trying to do for the patient? Relieve or eliminate the symptoms? Reduce the number of adverse events? Improve functions or test scores?

(Source: Ebling Library, University of Wisconsin-Madison, viewed online 18 February 2011)

Constructing Well-Built Clinical Questions using PICO – examples of using the PICO method from the University of Washington HealthLinks website

How to Answer Your Clinical Questions More Efficiently (Article) – (source: Family Practice Management July/August 2005)

Step Two: Finding the Evidence

It is important when searching for evidence that search terms are referred back to your original PICO question. The type of evidence located may include:

Systematic reviews
Meta-analysis
Randomised controlled clinical trials
Case-controlled studies
Case series and case reports
Qualitative evidence

When forming your question think of alternate keywords, including alternate spelling and terms for example:

Teenagers: adolescents, adolescent, adolescence, youth, young people
Hypnosis: hypnoses, hypnotism, hypnotise , hypnotize, hypnotherapy
Smoking: smokes, tobacco, cigarette, stop (smoking), quit, quitting

You also need to think about the following:

Are there other words that mean the same thing (synonyms)? e.g. adolescents, adolescence, youth, young people
Are any of the important words singular and plural? e.g. child/children
Are words used differently in different countries? e.g. operation/surgery
Are any of the words commonly used as abbreviations? e.g. CHF or congestive heart failure

Levels of Evidence

There are varying levels of information or evidence available. One way to look at the levels of Evidence available is as follows – the higher the level, the better the quality; the lower the level, the greater the bias.

Oxford Centre for Evidence-based Medicine - Levels of Evidence (March 2009)

Step Three: Appraising the Evidence

The purpose of critical appraisal is to determine the relevance of the material collected in relation to the clinical question raised. (Source: Cleary- Holdforth J, Leufer T, 2008 ‘Essential elements in developing evidence-based practice' Nursing Standard. 23, 2, 42-46).

Appraising the Evidence – from the book, Evidence-Based Practice for Information Professionals: A Handbook Edited

Critical Appraisal - useful tools and downloads for the critical appraisal of medical evidence from the Centre for Evidence Based Medicine

Teaching critical appraisal skills in health care settings (Review) - the Cochrane Collaboration. Published by JohnWiley & Sons, Ltd

Bias and the Evidence

Evidence-based public health: the importance of finding ‘difficult to locate' public health and health promotion intervention studies for systematic reviews - Faline Howes , Jodie Doyle, Nicki Jackson and Elizabeth Waters (Source: Journal of Public Health Vol. 26, No. 1, pp. 101–104).

Step Four: Applying the Evidence

Once the evidence has been appraised, and the best available evidence selected, it must be applied to your local situation.

Below is a list of questions you may ask to help determine how evidence applies:

User group

Is my patient similar to those in the study group?
How much would my patient benefit from the treatment?
Can the study results be applied to my patient?
What is my patient's risk for adverse affects?
Have all the outcomes been considered and are they appropriate for the patient?

Cost

Is the test affordable, accurate and realistic in my hospital?
Are there any negative side affects for users that may be costly in the long run?
How big an impact will be achieved and is it worth the cost?
Are there more affordable alternative therapies?

Severity

What is the level of severity of the issue?
Will implementation make a difference? If so, how much, and is it worth the effort?
Are the potential consequences so severe that any solution will only work in the short term?

(Source: Applying the Evidence Worksheet, from the Dartmouth Biomedical Libraries, viewed online 25 July 2011) and (Source: Evidence-Based Practice, from the University of Minnesota Libraries, viewed online 25 July 2011)

Step Five: Evaluating Performance

To complete the cycle clinicians should evaluate their own performance and focus on earlier steps which may require future improvement. Clinicians can evaluate their progress at each stage by asking some or all of the following questions:

Was the question answerable?
Was the diagnosis and treatment successful?
How quickly was good evidence located?
Is there new information/data in the literature?
How can I improve/update my clinical decision?
Was the application of the new information or procedure effective?
Should this new information and/or clinical practice procedure continue to be included in day to day applications?
How could any of the 5 steps improve the next time a question is asked?

(Source: Straus, E and Sackett D L 1998, ‘Getting research findings into practice Using research findings in clinical practice' BMJ Vol.317 p.339-342) and (Source: Johnson, C 2008, ‘Evidence-based practice in 5 simple steps' Journal of Manipulative and Physiological Therapeutics Vol. 31 p.169-170).