EBM Flashcards
number of cases present in a population at a given time
prevalence
number of new cases in a population within a specified time
incidence
study which compares the freq of a proposed risk factor between 2 groups - those with the disease and those without
case control
study which identifies subjects exposed to a proposed cause and those who are unexposed. The incidence of the disease is then calculated over time usually prospectively
cohort study
number needed to treat with a drug to prevent one new case or death
NNT
NNT formula
(1/absolute risk reduction) x100
how to calculate absolute risk
number of events in treated/control group divided by the number of people in the group
how do you calculate absolute risk reduction
absolute risk of events in control - absolute risk of events in treatment group
ARC - ART
how to calculate relative risk
absolute risk of event in treated group/ absolute risk of event in control
ART/ARC
how to calculate relative risk reduction
(absolute risk of control group - absolute risk of treatment group)/absolute risk of control group
(ARC-ART)/ARC or 1-RR
what is the gold standard study type
double blind randomised control trial
systematic merging of similar trials that may be used to explain data inconsistencies
meta analysis
an adaptive design that allows for learning during the experiment
Bayesian protocol
compares relative likelihood of an event occurring in two distinct groups
odds ratio
how to calculate odds ratio
disease none
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exposed A B
unexposed C D
AD/BC