EBM - course guide Flashcards
Describe the development of EBM
methods to critically appraise clinical info and classify it according to strength
concepts emerging from critical appraisal promoted EBM
suggested EBM should be used in clinical practice
criticism of EBM
Governments, healthcare commissioners and providers have used the jargon of EBM to justify decisions, directives, or incentives that are seen by clinicians as inappropriate
why is EBM important to clinicians
Patient Care Medical Knowledge Practice-Based Learning and Improvement Interpersonal and Communication skills Professionalism
it doesn’t replace clinical decision making
hierarchy of studies
systematic review and meta analysis RCT cohort case control ecological studies descriptive/cross sectional studies case report/series
what is association
the statistical dependence between two variables, that is the degree to which the rate of disease in persons with a specific exposure is either higher or lower than the rate of disease without that exposure.
A link, relationship or correlation
chance
inference is made from samples rather than the whole population to consider chance need to look at: sample size power P values and statistical significance
what is bias
a systematic error
2 types of bias
measurement and selection
how can you determine if there is a causal effect
observed association between exposure and disease
evidence from many sources supports this
what are the Bradford hill criteria
strength consistency specificity temporal relationship dose-response relationship plausibility coherence experimental evidence analogy
strength
magnitude of relative risk
strong association more likely to be causal than weak - could be confounding/bias
weak CAN be causal
consistency
different populations different study designs but same result likely causal without consistency can still be causal - eg extent of exposure may reduce impact of causal factor
specificity
if an exposure increases the risk of 1 disease but not the other
eg mesothelioma
one to one relationships rare
temporal relationshop
ESSENTIAL
easy to establish from cohort studies but not case control or cross sectional
dose-response relationship
increasing levels of exposure, increase the risk of disease
some have a threshold though instead of a monotonic trend
