《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。统计问题(10):随机对照试验的“风险”,你会计算吗?(多选)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。*请大家在看问题答案解析之前,先“投票”,也看看大家的结果QuestionThe 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.AnswerThe risks are calculated as:a=40/290b=60/300d=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:风险计算如下:A = 40/290B = 60/300D = 1 /(b减去a), number needed to treat (需治数),指防止1例不良事件发生或得到1例有利结果需要治疗的病例数C选项是绝对风险降低。这6.2%的风险降低率可以除以普通病房的风险(20%),得出相对的风险降低率,即31%。 所以答案是选择 ABD原文出处:BMJ杂志