【原】随机对照试验的“风险”,你会计算吗?
《英国医学会杂志》(BMJ)自2008年9月开始至2015年由两位流行病与统计学专家不间断地出了300多期statistical question系列。在这个系列中,两位学者每次出一道统计学选择题,进行选择并解释。现在我精选300道Statistical Question,形成中文版,请有兴趣的朋友们进行回答。
BMJ 统计问题(10):随机对照试验的“风险”,你会计算吗?
下面显示了中风患者常规医院护理(General Ward)与有组织护理(Stroke unit)两种方法的随机对照试验结果。
Question
The results of a randomised controlledtrial of organised care for stroke patients versus usual hospital care areshown below.
Whichof the following statements is or are true?
a)The risk of death on the stroke unit was 13.8%
b)The risk of death on the general ward was 20%
c)The relative risk reduction was 6.2%
d)The number needed to treat was 16.
Answer
The risks are calculated as:
a=40/290
b=60/300
d=1/(b minus a)
Answer c is the absolute risk reduction. This 6.2%reduction in risk may be divided by the risk in the general ward (20%) to givethe relative risk reduction—that is, 31%.
中文解释:
所以答案是选择 ABD