ON THE NEED FOR THE RARE DISEASE ASSUMPTION IN CASE-CONTROL STUDIES
ON THE NEED FOR THE RARE DISEASE ASSUMPTION IN CASE-CONTROL STUDIES
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DOI：
10.1093/oxfordjournals.aje.a113439
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发表时间：
1982-01-01
影响因子：
5
通讯作者：
THOMAS, DC
中科院分区：
文献类型：
--
作者：
GREENLAND, S;THOMAS, DC
在病例对照研究中，匹配和不匹配的比值比是发病率密度比的一致估计的条件进行了检查。在“发病率-密度”抽样下，对照组选自每个病例发病时的风险人群，匹配估计量是一致的。相比之下，非匹配估计量存在偏倚，除非风险人群中的暴露比例在研究期间保持不变;但是，偏倚可以忽略不计，除非暴露比例存在非常大的变化。这些结果不需要假设疾病的罕见性。当风险比是感兴趣的参数时，为了使比值比是一致的估计量，需要稀有性假设。在这种情况下，在“发病率-密度”抽样下获得的比值比通常比在“累积发病率”抽样下获得的比值比提供更好的风险比近似值，在“累积发病率”抽样下，对照组选自研究期结束时仍未受影响的对照组。然而，即使这种疾病是罕见的，累积抽样下获得的比值比不需要一致地估计任何参数的利益，除非暴露的比例是近似恒定的。
The conditions under which matched and unmatched odds ratios are consistent estimators of the incidence-density ratio in case-control studies are examined. Under ''incidence-density'' sampling, in which controls are selected from those at risk at the time of onset of each case, the matched estimator is consistent. In contrast, the unmatched estimator is biased unless the proportion exposed in the population at risk is constant over the study period; the bias is, however, negligible unless there is very large variation in the proportion exposed. No assumption of rarity of the disease is needed for these results. When the risk ratio is the parameter of interest, the assumption of rarity is needed for the odds ratio to be a consistent estimator. In such situations, the odds ratio obtained under ''incidence-density'' sampling will in general provide a better approximation to the risk ratio than will the odds ratio obtained under ''cumulative-incidence'' sampling, in which controls are selected from those still unaffected at the end of the study period. Even if the disease is rare, however, the odds ratio obtained under cumulative sampling need not consistently estimate any parameter of interest unless the proportion exposed is approximately constant.