BIASES IN PREVALENT COHORTS
BIASES IN PREVALENT COHORTS
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DOI：
10.2307/2531529
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发表时间：
1987-12-01
期刊：
影响因子：
1.9
通讯作者：
GAIL, MH
中科院分区：
文献类型：
--
作者：
BROOKMEYER, R;GAIL, MH
获得性免疫缺陷综合征（AIDS）的几项自然史研究是基于对入组前感染AIDS病毒的个体的随访。研究艾滋病临床前病程的自然时间尺度是自首次感染以来的时间;然而，在这些研究中，感染时间是一个随机的未知数。使用随访时间而不是从感染的时间固有的偏差进行了研究，估计的累积分布函数和风险比的比例风险模型与固定和时间依赖的协变量。虽然偏差的大小取决于流行曲线的形状，但建立了一些偏差的界限。这些结果有助于解释流行队列研究，然后将其与新感染个体的研究进行比较，以评估研究结果的一致性。
Several natural history studies of the Acquired Immunodeficiency Syndrome (AIDS) have been based on the follow-up of individuals infected with the AIDS virus prior to enrollment. The natural time scale for studying the preclinical course of AIDS is the time since first infection; however, in these studies the time at infection was a random unknown quantity. The biases inherent in using follow-up time instead of time from infection are investigated for estimation of both the cumulative distribution function and the hazard ratio for proportional hazards models with both fixed and time-dependent covariates. Although the magnitudes of the biases depend on the shape of the epidemic curve, a number of bounds on the biases are established. These results are useful for interpreting prevalent cohort studies and then comparing them with studies on newly infected individuals in order to assess consistency of results across studies.