22.2 The principles of evidence-based medicine

Question 1

What is evidence based medicine?

Answer 1

Evidence-based medicine is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients’

The 3 principles of EBM (Fig 22.2.1):

1. Clinical expertise
2. Best research evidence
3. Patient values/experiences

Question 2

What is evidence based clinical practice

Answer 2

Evidence-based clinical practice is an approach to decision making in which the clinician uses the best evidence available, in consultation with the patient, to decide upon the option that suits that patient best

Question 3

Rank the following in strength of evidence (from low to high):

Cohort study
Case control study
Randomized control trial
Case study/series
Pseudo-randomized control trial

Answer 3

See Figure 22.2.2:

Case study/series
Case control study
Cohort study
Pseudo-randomized control trial
Randomized control trial

Question 4

What defines the quality of evidence reported in a clinical trial

Answer 4

It’s internal validity:
extent to which the investigators have minimized bias in study design and execution

Question 5

List and define 4 types of bias that can threaten the internal validity of a study

Answer 5

1. Selection bias: participants in sample don’t reflect the population
2. Performace bias: participants receive unequal care (apart from intervention being tested)
3. Attrition bias: certain subgroups are lost to follow up
4. Assessment bias: participants/investigators are aware of intervention assignments

Question 6

what is publication bias?

Answer 6

Results of a portion of trials are published
(positive results more likely to be published than negative results)

Question 7

List the 6 key steps to critical appraisal

Answer 7

Table 22.2.2:

1. ASSESS the patient

The process begins with the patient who has a clinical problem or question arising from their care

2. ASK the question

A well-constructed clinical question is derived

3. ACQUIRE the evidence

Conduct a search and choose the most appropriate resources

4. APPRAISE the evidence

Appraise the evidence: valid and applicable?

5. APPLY: talk with the patient

Integrate: evidence and clinical expertise with patient’s preferences and apply

6. EVALUATE: review outcomes and process

Evaluate the patient’s outcomes and performance

Question 8

A well built clinical question follows the “PICO” format.

Definte the 4 elements of PICO

Answer 8

PICO:
1. P: the specific clinical Patient, Problem, or Population

2. Intervention in question
3. Comparison intervention when relevant
4. the clinical Outcome or outcomes of interest

Question 9

As per the 4S Model, what is the hierarchy of 4 major evidence resources (lowest to highest)

Answer 9

1. Studies (published reports of clinical trials etc)
2. Syntheses (meta-analyses and systematic reviews i.e. Cochrane Database)
3. Synopses (evidence-based abstracts printed in journals and other credible sources)
4. Systems (computerized serach and decision support systems, i.e. UptoDate)

Question 10

What is the rationale for EBM in palliative care. List 3 reasons.

Answer 10

1. To provide effective, quality care
2. With increasing demand for PC, to determine how/which services to provide
3. To meet performance requirements for health care funding

Question 11

Only about half of palliative care decisions are research based, at best.

List 3 barriers to EBM in palliative care

Answer 11

1. Paucity of research evidence in PC
2. Lack of research capacity.
3. Traditional critical appraisal skills ill suited to pall care literature
4. Unsupportive organizational cultures

Question 12

List 3 limitations of EBM