Memory Joggers: EBM Risk
| Disease |
| Exposure |
|
YES |
NO |
|
| Y |
a |
b |
e |
| X |
c |
d |
f |
|
g |
h |
i |
e = a + b
f = c + d
g = a + c
h = b + d
i = a + b + c + d
Incidence Y = a/e
Incidence X = c/f
Relative Risk (RR) = Incidence Y / Incidence X
Relative Risk Reduction (RRR) = 1 - Relative Risk
Absolute Risk Reduction (ARR) = Incidence X - Incidence Y
(Attributable Risk)
Number Needed to Treat (NNT) = 1 /ARR
95% Confidence Interval (CI) = RR1±z/x
z = 1.96 for 95% Confidence Interval
|
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