Evidence-Based Medicine Flashcards
Why use research to answer clinical questions? (6 reasons)
1) Provide information on issues of health
2) Research is credible and accessible
3) To be aware of the science underlying naturopathic medicine and medicine
4) To provide improvements to clinical care
5) Current practices (treatments, diagnostic tools) may not be effective
6) Current practices may be harmful
What is evidence-based medicine?
The conscientious, explicit and judicious use of current best evidence in making decisions about care of individual patients.
It is an integration of clinical expertise and experience with the best possible evidence towards patient care.
What is clinical expertise?
The proficiency and judgement that is gained over years of clinical experience.
Reflected in: efficient diagnosis and the use of information on an individual level in a compassionate manner.
What does best available evidence include?
Basic science and clinical research about:
- accuracy and precision of diagnostic tests
- prognostic markers
- efficacy and safety of therapeutic, rehabilitative and preventative regimens.
What is the purpose of descriptive studies?
To describe the current situation (ie. by taking surveys of people or practice)
What is an example of a descriptive study?
How many people with cancer take natural health products during chemotherapy?
What is the purpose of qualitative research?
To look for and explanation for current behaviours. This is done through interviews or surveys.
What is an example of a qualitative research question?
Why do cancer patients take natural health products?
What is the purpose of quantitative research?
To test a hypothesis based on a prediction. This is done through clinical trials and laboratory experiments.
What is an example of a quantitative research question?
Does Co-Q10 reduce the toxicity of certain chemotherapy drugs to heart muscle?
What is the purpose of multi-centre trials and systematic reviews of controlled trials?
To generalize for standards of practice and cost effectiveness
What is the order of study/research types in the EBM Hierarchy pyramid? (From top to bottom)
Systematic reviews and meta-analyses Randomized controlled double blind studies Cohort studies Case controlled series Case series Cases reports Ideas, editorials, opinions Animal research In vitro research
What does the PICO(S) question model stand for?
Patient population Intervention of interest Control/comparison of interest Outcome of interest Safety/risk of intervention
Define causation.
A relationship by which an antecedent (prior) event, condition or characteristic was necessary for the occurrence of some other event, condition or characteristic. (X is necessary to achieve Y)
Is it possible to absolutely prove causal relationships?
No, it is only possible to strengthen cause-effect relationships. Reproduce ability and repetition are key.
Define correlation.
The illustration of a relationship between two variables. Specifically, it expresses the degree and direction of the relationship between two random variables.
What is a positive correlation?
When one variable increases, the other variable increases. Or when one variable decreases, the other also decreases. The direction of the two variables is always the same.
What is a negative correlation?
When one variable increases, the other decreases. The directions of the two variables is opposite.
What is the difference between association/correlation and cause?
Not all associations/correlations are causal. And association can appear to be causal if any of the following exist:
-bias, chance, or confounding
Define bias.
Anything that prevents a truly objective conclusion.
Define chance.
The ever-present randomness inherent in all things.
Define confounding.
A variable that is associated with both the dependent and the independent variable, which prevents the separation of the contributions of each separate variable.
What are the 8 principles of causation?
1) temporality
2) strength
3) dose-response
4) reversibility
5) consistency
6) biological plausibility
7) specificity
8) analogy
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Define temporality.
When cause precedes effect - established in an RCT or a prospective cohort trial (looking ahead).
Can be overlooked when looking at case controlled trials or case studies (looking behind) a they measure cause and effect at the same time
-sometimes we can not be certain if exposure preceded the outcome
Define strength of an association.
A stronger association (as measured by effect measures) is better evidence for a causal relationship than a weak association. (Ie. smoking and lung cancer vs smoking and renal cancer.)
-bias can cause a stronger or a weaker association
Define the dose-response relationship.
Varying amounts of cause are related to varying amounts of effect (ie. number of cigarettes smoked per day and lung cancer rates). A dose response relationship is good evidence for a causal relationship especially if it is a strong dose-response.
-this does not exclude confounding variables/factors (ie. suppose heavy smokers tend to use more inhaled drugs or drink more alcohol).
Define reversible associations.
Association between cause and effect a reversible. Taking cause away decreases the effect.
-confounding can be responsible for this. (Ie. those who quit smoking may actually have some other factors responsible for the decrease in cancer deaths - will to survive/fighters)
Define consistancy.
Several studies conducted at different times, in different settings and with different kinds of patients all come to the same conclusions.
-lack of consistency does not mean that the results of a well-done study are invalid.
