Epidemiology (Segars) Flashcards
__=NEW occurences of an outcome/disease
__=EXISTING occurrences of an outcome/disease
BIG STAR
Incidence
Prevalence
Both are a PROPORTION..a simple %..part over whole
Risk, attack rate, and cumulative incidence are AKA as ___
Incidence
Formula for incidence? Who do you want to include/leave out?
BIG STAR
new cases illness/# people at risk of illness
ALWAYS substract out (from starting pop.), those who are NOT at risk (already have the disease or are immune)
formula for prevalence?
Total # cases of illness/# people in population
How do you calculate Risk in Exposed (2x2)?
A/(A+B)
How do you calculate Risk in Non-exposed (2x2)
C/C+D)
If you are solving Absolute risk reduction (aka Attributable risk), how do you do it?
Subtract
risk DIFFERENCE of outcome attributable to exposure difference between groups
How do you calculate Relative risk reduction?
ARR/Risk of unexposed
How do you calculate NNT/NNH?
1/ARR
always round up to next whole person
How do you calculate Risk Ratio (aka Relative risk)?
Risk of outcome (in exposed)/Risk of outcome (in non-exposed)
__=FREQUENCY of an outcome occurring vs NOT occurring in a specific group
BIG STAR
Odds
Formula for OR in Cases? In controls?
Cases=A/C
Controls=B/D
RR/OR/HR that is >1.0?
RR/OR/HR that is <1.0?
> 1.0=event/outcome is MORE LIKELY to occur in the comparison group (numerator group)
<1.0=event/outcome is LESS LIKELY to occur in the comparison group (numerator group)
When looking at CI for Ratio’s, when is it statistically significant?
if BOTH values are on same side of 1.0, it is ALWAYS statistically significant
