Biases in prevalent cohorts. NLM AIDSLINE Important note: Information in this article was accurate in 1988. The state of the art may have changed since the publication date.

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Biases in prevalent cohorts.

Biometrics. 1987 Dec;43(4):739-49. Unique Identifier : AIDSLINE MED/88107989
Brookmeyer R; Gail MH; Department of Biostatistics, Johns Hopkins University School of; Hygiene and Public Health, Baltimore, Maryland 21205.

Abstract: 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.
Keywords: Acquired Immunodeficiency Syndrome/PHYSIOPATHOLOGY/*TRANSMISSION Analysis of Variance Human Models, Theoretical Probability Risk Factors JOURNAL ARTICLE

KWDacquiredimmunodeficiencysyndrome/physiopathology/KWDtransmissionanalysisofvariancehumanmodels,theoreticalprobabilityriskfactorsjournalarticle
880530
M8850462

Copyright © 1988 - National Library of Medicine. Reproduced under license with the National Library of Medicine, Bethesda, MD.

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