Why use Evidence Based Medicine?

Purpose: To improve the care provided for patients

Aim: To change clinicians habits of learning so that they use their time more efficiently and effectively to discover the interventions that are most likely to benefit the patients

Outcome: Improved care of patients

Is EBM a fashion or is it a real improvement?

There are 5 questions worth asking whenever any change is suggested

1. What are we trying to achieve?
2. What is our current knowledge on this subject?
3. How will we know if the change proposed is an improvement?
4. What changes can we make?
5. How will we ensure that improvement continues in a cycle of feedback and change?

What are we trying to achieve?

• use current best evidence in making decisions about the care of individual patients
• integrate our clinical expertise with the best available external clinical evidence from systematic research

What is our current knowledge on this subject?

• new information now creates more frequent and major changes in optimal patient care
• We usually fail to keep up with the new evidence available. Although we say we need important information about twice a week and answer these questions by looking at textbooks & journals. We usually generate 2 question for every 3 patients we see (50% on therapeutics, 25% on diagnosis) and usually ask our colleagues (30%) for the answers. Although estimates are that we would need to read 20 articles a day to keep up to date, most consultants spend only 15-60 min per week reading around their patients.
• our clinical performance deteriorates over time
• Using traditional CME doesn’t help much. Traditional CME doesn’t change our performance. Paradoxically when you want CME you may not need it!
• A different approach to clinical learning has been shown to keep doctors up to date. McMaster University life long learning skills are associated with maintaining clinical competence.

How will we know if the change proposed is an improvement?

• When we can access from our desks ‘easy to use’ EBM information, which we use a couple of times a day to update our knowledge.
• When we have abandoned our old learning styles because we are confident we can answer our clinical questions in a better way

What changes can we make?

• Acknowledge there is a problem- does out of date knowledge smell?
• Decide to examine our existing learning methods- there must be a better way!
• Try to ask clinical questions we can answer. Pose the patient problem with an intervention, a comparison and an outcome e.g. In patients with heart failure from dilated cardiomyopathy who are in sinus rhythm would adding anticoagulation with warfarin to standard heart failure therapy when compared with standard therapy alone lead to lower mortality or morbidity form thromboembolism? Is this enough to be worth the increased risk of bleeding?
• Stop buying textbooks on therapeutics- At best, they are 5 years out of date!
• Stop reading poor quality sources of information- we may be wasting our valuable time!
• Check the colleague we ask for advice has a good source of his/her knowledge.
• Search for the best evidence- learn to practice EBM, use EBM summaries generated by others, use EBM protocols developed by others
• Appraise the evidence critically- Is it both valid (close to the truth)? and clinically important?
• Apply this valid and important evidence when we care for patient. Integrate this information with our clinical expertise and decide whether and how to incorporate it the care of our patients.

How will we ensure that improvement continues in a cycle of feedback and change?

• Invite critical comment on the clinical questions we ask and the way we answer them
• Inform EBM providers and evangelists of our difficulties accessing and using EBM in busy general practice

Glossary of some EBM terms

Odds Ratio: The odds of an experimental patient having an adverse event relative to a control patient

Confidence Intervals: A 95% CI is the range of values within which we can be 95% sure the true value lies for the whole population of patients from whom the study patient were selected.

Terms used in Therapeutics

Absolute Risk Reduction (ARR): The absolute difference in outcome rates

Number needed to Treat (NNT): The number of patients who nee to be treated to prevent one more adverse event.

Relative Risk Reduction (RRR): The proportional reduction in outcome rates between control and experimental patients in a trial

Types and Strength of Efficacy Evidence

1. Strong Evidence from at least 1 systematic review of multiple well-designed randomised controlled trials
2. Strong Evidence from at least 1 properly designed randomised controlled trial of appropriate size
3. Evidence from well designed trials without randomisation, single group pre-post, cohort, time series or matched case-controlled studies
4. Evidence from well designed non experimental studies from more than 1 centre or research group
5. Opinions of respected authorities, based on clinical evidence, descriptive studies or reports of expert committees

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