1.RR( risk ratio) 風(fēng)險(xiǎn)比,也稱(chēng)為相對(duì)危險(xiǎn)度（relative risk，RR）辽剧。指暴露于某因素發(fā)生某事件的風(fēng)險(xiǎn)送淆，即A/(A+B)，除以未暴露人群發(fā)生的該事件的風(fēng)險(xiǎn)怕轿，即C/(C+D)偷崩，所得的比值，即RR=［A/(A+B)］/［C/(C+D)］撞羽，RR適用于隊(duì)列研究或隨機(jī)對(duì)照試驗(yàn)阐斜。
2.OR(odds ratio) 比值比。OR=(A/B)÷(C/D)=AD/BC诀紊。RR和OR兩個(gè)公式的區(qū)別谒出，A/(A+B) 指暴露于某因素發(fā)生某事件的風(fēng)險(xiǎn)；A/B 指暴露人群中病例的比例邻奠，C/D指非暴露人群中病例的比例笤喳，所以O(shè)R也被稱(chēng)為優(yōu)勢(shì)比。當(dāng)疾病非常罕見(jiàn)時(shí)碌宴，OR成苯疲可作為RR的近似值。OR通常適用于病例對(duì)照研究唧喉，也可以運(yùn)用于前瞻性的研究（當(dāng)觀察時(shí)間相等時(shí)）捣卤。Logsitic回歸模型可以得到OR值。
3.HR（hazard ratio）風(fēng)險(xiǎn)比［HR=暴露組的風(fēng)險(xiǎn)函數(shù)h1(t)/非暴露組的風(fēng)險(xiǎn)函數(shù)h2(t),t指在相同的時(shí)間點(diǎn)上］八孝。而風(fēng)險(xiǎn)函數(shù)指危險(xiǎn)率函數(shù)董朝、條件死亡率、瞬時(shí)死亡率干跛。Cox比例風(fēng)險(xiǎn)模型可以得到HR子姜。資料的類(lèi)型通常是臨床治療性研究，也可以是流行病學(xué)的隊(duì)列觀察性研究楼入。
Hazard is an instaneous rate of a given outcome, which indeed factors time in. Hazard ratio is a raio of two hazards (Exp/Ctl) at that given time. By using hazard ratio as a summary estimate of the treatment effects in suvival data, we assume the hazard ratio is constant over time, which is a strong assumption and a basis for cox regression. This doesn’t mean hazard would not change (actually, hazard always change over time), though – we just require the ratio of the hazards is constant. HR有時(shí)間因素在內(nèi)哥捕，換句話(huà)說(shuō)牧抽，包含了時(shí)間效應(yīng)的RR就是HR；生存資料中遥赚，RR考慮了終點(diǎn)事件的差異扬舒，而HR不僅考慮了終點(diǎn)事件的有無(wú)，還考慮了到達(dá)終點(diǎn)所用的時(shí)間及截尾數(shù)據(jù)凫佛。
