Introduction to evidence based medicine

Question 1

What is evidence based medicine?

Answer 1

Evidence-based medicine is a systematic process primarily aimed at improving the care of patients.

Question 2

What is the evidence-based medicine triad made of?

Answer 2

1. Clinical judgment
2. Relevant scientific evidence
3. Patients’ values and preferences
   These all come together to form the components of evidence-based medicine.

Question 3

From video 1: What is evidence-based medicine based on what?

Answer 3

1. Research evidence
2. Experience and wisdom
3. Patients need and preferences
4. Toolbox of approaches. Which to choose in a situation. Services are built on a foundation of evidence.

Question 4

Five steps of evidence-based medicine

Answer 4

Ask - structure the clinical question
Acquire - acquire the evidence
Appraise - appraise the evidence
Apply - apply the evidence
Assess - analyze and adjust outcomes

Question 5

Discuss the advantages and limitations of evidence-based medicine.

Answer 5

Advantages:

• EBM attempts to find and incorporate interventions that work, not those that should or seem to work.
• Allows practitioners to use critical thinking skills
• Helps improve the ability to keep up with new information and developments

Limitations:

• EBM requires specialized knowledge, skills, and support mechanisms.
• The EBM process can be labor-intensive and time-consuming
• Requires access to medical literature
• Publication bias and conflict of interest

Question 6

What is the hierarchy of evidence?

Answer 6

Higher to lower [quality of evidence]

1. RCT - randomized controlled trials. no bias
2. Cohort
3. Case-control
4. Cross-sectional
5. Case reports/Series
6. Ideas, opinions, and reviews

Lower to higher - Risk of bias

Question 7

What is the evidence we speak of here?

Answer 7

• Findings from patient-centered clinical research that are relevant to patient care.
• Applied research from the laboratory.
• Clinical research.

Question 8

Importance of learning Evidence-based medicine.

Answer 8

Helps to make health professionals make more valid and reliable recommendations. It will be easier to convince the health care team when recommendations are based on principles of Evidence-based medicine.

Keep up with a large pool of information

Ensure research findings incorporation into clinical practice

Question 9

Case example

Answer 9

> The patient is a 65 year old male with a long history of type 2 diabetes and obesity.
Otherwise, his medical history is unremarkable. He does not smoke. He had knee surgery 10 years ago but otherwise has had no other major medical problems.

> Over the years he has tried numerous diets and exercise programs to reduce his weight but has not been very successful.

> His granddaughter just started high school and he wants to see her graduate and go on to college. He understands that his diabetes puts him at a high risk for heart disease and is frustrated that he cannot lose the necessary weight.

> His neighbour told him about a colleague at work who had his stomach stapled and as a result not only lost over 100 lbs. but also “cured” his diabetes.
He wants to know if this procedure really works.

Question 10

How do you formulate clinical questions?

Answer 10

To practice evidence-based medicine the initial step is to convert a clinical encounter into a clinical question.

A useful approach to doing this is PICO:-

Patient
Intervention
Comparison
Outcome

Question 11

Patient Intervention Comparison Outcome framework

Answer 11

1. Patient/ Population: Which patients or population group of patients are you interested in? Is it necessary to consider any subgroups?
2. Intervention: Which intervention/treatment is being evaluated?
3. Comparison/ Control: What is the main alternative compared to intervention?
4. Outcome: What is the most important outcome for the patient?

Question 12

Asking based on PICO

Answer 12

PICO is a mnemonic that helps one remember the key components of a well-focused question.

The question needs to
Identify the key problem of the patient,
What treatment or tests you are considering for the patient,
what alternative treatment or tests are being considered (if any)
and what is the desired outcome to promote or avoid?

Question 13

Patient problem

Answer 13

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 gender, age, or race of a patient might be relevant to the diagnosis or treatment of a disease.

Question 14

Intervention, prognostic factor, or exposure.

Answer 14

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?
Or what factor may influence the prognosis of the patient - age, co-existing problems, or previous exposure?

Question 15

Comparison

Answer 15

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.

Question 16

Outcome

Answer 16

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 function or test scores?

Question 17

Types of study

Answer 17

1. Meta-analysis
2. Systematic review
3. Randomized controlled trial
4. Cohort studies
5. Case-control studies
6. Case Series/Case Reports
7. Animal research

Question 18

For our patient in our case study, the clinical question is:

Answer 18

> In patients with type 2 diabetes and obesity, is bariatric surgery more effective than standard medical therapy at increasing the probability of remission of diabetes?

> It is atherapy questionand the best evidence would be arandomized controlled trial (RCT). If we found numerous RCTs, then we might want to look for asystematic review.

Question 19

Acquiring the evidence

Answer 19

> Constructing a well-built clinical question can lead directly to a well-built search strategy.

> Note that you may not use all the information in PICO or well-built clinical question in your MEDLINE strategy.

> In the following example we did not use the term “male.”

> We also did not include the wordtherapy.
Instead we used the Clinical Query for Therapy or the publication type,randomized controlled trial, to get at the concept of treatment.

> However, you may consider the issue of gender later when you review the articles for applicability to your patient

Question 20

When Selecting the resources Evidence-based practice requires to do what?

Answer 20

Evidence-Based Practice requires that clinicians search the literature to find answers to their clinical questions.
There are literally millions of published reports, journal articles, correspondence, and studies available to clinicians.
Choosing the best resource to search for is an important decision.

Question 21

What are the large databases for medical research and what do they do?

Answer 21

Large databases such as PubMed/MEDLINE will give you access to the primary literature.

The Cochrane Library provides access to systematic reviews which help summarize the results from a number of studies. These are often called “pre-appraised” or EBP resources.

Question 22

Appraise: What is involved in appraisal?

Answer 22

There are three basic questions that need to be answered for every type of study:
Are the results of the study valid?
What are the results?
Will the results help in caring for my patient?

The issue of validity speaks to the “truthfulness” of the information.
The validity criteria should be applied before an extensive analysis of the study data.
If the study is not valid, the data may not be useful.
How large was the treatment effect? What was the absolute risk reduction?

Question 23

Discuss Clinical significance versus Statistical significance

Answer 23

To be clinically important requires a substantial change in an outcome that matters.
Statistically significant changes, however, can be observed with trivial outcomes.
And because statistical significance is powerfully influenced by the number of observations, statistically significant changes can be observed with trivial (small) changes in important outcomes.
Large studies can be significant without being clinically important and small studies may be important without being significant.”

Question 24

Clinical significance has little to do with what? what does it depend on?

Answer 24

Clinical significance has little to do with statistics and is a matter of judgment.
Clinical significance often depends on the magnitude of the effect being studied.

Question 25

What question does clinical significance answer?

Answer 25

It answers the question “Is the difference between groups large enough to be worth achieving?“

Question 26

Studies can be statistically significant yet

Answer 26

clinically insignificant.

Question 27

Apply the results to your patient. Questions to ask (yourself)

Answer 27

> Were the study patients similar to my population of interest?
Does your population match the study inclusion criteria?
If not, are there compelling reasons why the results should not apply to your population?

> Were all clinically important outcomes considered?
What were the primary and secondary endpoints studied?
Were surrogate endpoints used?

> Are the likely treatment benefits worth the potential harm and costs?

> What is the number needed to treat (NNT) to prevent one adverse outcome or produce one positive outcome?

> Is the reduction of clinical endpoints worth the potential harms of the surgery or the cost of surgery?

Question 28

Stages of evaluating the process

Answer 28

Stage 1: Asking the question
Stage 2: Finding the evidence
Stage 3: Appraising and interpreting the evidence
Stage 4: Acting on the evidence

Question 29

Evaluating the process

Stage 1 Asking the question

Answer 29

Was my question answerable?

Was my question stated explicitly enough to help me in my search for the evidence?

Question 30

Evaluating the process

Stage 2 Finding the evidence

Answer 30

Did I search the right sources for the evidence or was there somewhere else I should have looked?
Did I manage to find sound evidence quickly and efficiently?

Question 31

Stage 3: Appraising and interpreting the evidence

Answer 31

Did I appraise the evidence effectively?

Do I need to improve my critical appraisal skills?

Question 32

Stage 4: Acting on the evidence

Answer 32

Did I involve the patient (and appropriate others) in the decision to act on the evidence?
Should I have attempted to answer my initial query a different way (eg. considered an alternative treatment to the one evidence was sought for)?

Question 33

What are Pre-appraised resources?

Answer 33

Filtered resources that have been reviewed for quality and relevance to clinical care.

Question 34

What is in the database?

Answer 34

Databases:

> Electronic textbooks and libraries

> Meta-Search Engines- TRIP Database searches across multiple internet sites for evidence-based content.

> It covers key medical journals, Cochrane Systematic reviews, clinical guidelines, and other highly relevant websites to help health professionals find high-quality clinical evidence for clinical practice.