q15! - sarim

[ArchivalUser]

A 62-year-old woman presents to the emergency with the sudden onset of weakness on the right side of her body. Physical exam is significant for a dense right hemiplegia. At CT angiogram of the cerebral vascular shows a large clot in the left middle meningeal artery. Thrombolytic therapy is promptly initiated. Suppose that thrombolytic therapy increases the risk of intracranial hemorrhage from 0.2% to 1%. How many patients would have to be treated with thrombolytics before causing an intracranial hemorrhage?

A.50
B.75
C.100
D.125
E.150
F.175
G.200

[ArchivalUser]

1/attributable risk
1/0.8%=0.125

[ArchivalUser]

D ,
1/0.8% : 125

[ArchivalUser]

DDD

[ArchivalUser]

right

NNH = 1 / ARI (Absolute Risk Increase)

since it's given in %, we can use the formula as:

NNH = 100 / ARI
...... = 100 / 1 - 0.2
...... = 100 / 0.8
...... = 125