Lecture 33: Evidence-based Practice Flashcards
What is evidence-based practice?
Bringing together best available evidence with clinical expertise as well as the patient values and choices
Within evidence-based practice:
- Research provides the evidence to guide your practice
- Evidence is evolving, you need to know how to evaluate it
What is the order of the hierarchy of evidence (Top to bottom) ?
- Systematic review and meta analyses of RCTs
- RCTs
- Cohort studies
- Case-control studies
- Cross sectional surveys
- Case studies
- Ideas, expert opinions, editorials
- Anecdotal - often seem to have the most influence on people’s opinions
Why is it important to appraise evidence and what should be considered when appraising it?
Don’t accept the results of an RCT just because it is an RCT
- Was it done well?
- Are the findings applicable to your patient/population?
- Are the outcomes meaningful to your patient?
*Cure
* Improved survival
* Fewer symptoms
* Better quality of life
Why is it important to use all the evidence?
Don’t reject the results of an observational study simply because it is an observational study
- What is the best study design to answer a particular question?
- Appraise the methods and results of the studies addressing the question
When finding how common a disease is or who is most likely to get it, what type of question is being asked and which types of studies are best for answering it?
Epidemiological question
Cross-sectional or cohort studies of incidence
& prevalence
When finding the causes of disease, what type of question is being asked and which types of studies are best for answering it?
Epidemiological question
Cohort or case-control studies
When finding how good a diagnostic test is, what type of question is being asked and which type of studies are best for answering it?
Clinical question
Diagnostic accuracy studies (cross-sectional)
Helps with determining:
- If the test is positive – does this mean the disease is present?
- If the test is negative – does this mean no disease?
When finding the natural history of a disease, what type of question is being asked and which type of studies are best for answering it?
Clinical question
Cohort studies (case series) of people with the condition
When finding what best treatment, what type of question is being asked and which type of studies are best for answering it?
Treatment question
RCTs
When finding the harms of a treatment, what type of question is being asked and which types of studies are best for answering it?
Treatment question
Common harms may show up in RCTs
Rare or long-term harm – usually case-control or cohorts
Why it is important to have good evidence for interventions?
Good evidence is vital otherwise:
- Ineffective treatments are used (e.g. hydroxychloroquine for COVID19)
- Give treatments for which the harms outweigh the benefits (e.g. chest drain for pneumothorax)
- Fail to provide effective interventions (e.g. MMR vaccine)
- New expensive treatments may be no better than older cheaper ones
Why is it difficult to communicate evidence?
- Adverts backed by dubious scientific claims (e.g. vitamin C)
- Endorsements by prominent people (e.g. Trump and
hydroxychloroquine) - Scares and conspiracy theories (e.g. vaccines)
- The value that people place on individual stories may lead people to ignore objective evidence
Explain why evidence-based practice is important:
Evidence-based practice is important to ensure that the best available care is provided to patients. Good evidence is vital to ensure that effective treatments are used and that the benefits of any treatments outweigh the harms. Good evidence is also important so that clinicians do not forgo existing treatments in favour of new, often more expensive, treatments, which may not be better than the existing less expensive alternatives.
