Johnson E S
International Agency for Research on Cancer, Lyon, France.
J Occup Med. 1988 Jan;30(1):60-2.
In the analysis of retrospective cohort mortality studies, persons lost to follow-up are either withdrawn at the time of loss or are assumed to be alive at the end of the study. It has been advocated that the former method does not give a biased estimate of expected mortality in this group, and is therefore the preferred method. In this paper, it is argued that this approach is not always the best one, and that in certain situations, depending on the method of follow-up used, assuming that persons lost to follow-up are alive may give more accurate results than withdrawing them at the time of loss. Data from a recent study are used for illustration.
在回顾性队列死亡率研究的分析中，失访者要么在失访时被剔除，要么被假定在研究结束时仍然存活。有人主张，前一种方法不会对该组的预期死亡率给出有偏差的估计，因此是首选方法。本文认为，这种方法并非总是最佳方法，在某些情况下，根据所采用的随访方法，假定失访者仍然存活可能比在失访时将他们剔除能给出更准确的结果。本文用近期一项研究的数据进行说明。
