title: A Simulation Platform for Quantifying Survival Bias: An Application to Research on Determinants of Cognitive Decline.
abstract: Bias due to selective mortality is a potential concern in many studies and is especially relevant in cognitive aging research because cognitive impairment strongly predicts subsequent mortality. Biased estimation of the effect of an exposure on rate of cognitive decline can occur when mortality is a common effect of exposure and an unmeasured determinant of cognitive decline and in similar settings. This potential is often represented as collider-stratification bias in directed acyclic graphs, but it is difficult to anticipate the magnitude of bias. In this paper, we present a flexible simulation platform with which to quantify the expected bias in longitudinal studies of determinants of cognitive decline. We evaluated potential survival bias in naive analyses under several selective survival scenarios, assuming that exposure had no effect on cognitive decline for anyone in the population. Compared with the situation with no collider bias, the magnitude of bias was higher when exposure and an unmeasured determinant of cognitive decline interacted on the hazard ratio scale to influence mortality or when both exposure and rate of cognitive decline influenced mortality. Bias was, as expected, larger in high-mortality situations. This simulation platform provides a flexible tool for evaluating biases in studies with high mortality, as is common in cognitive aging research.
authors: Elizabeth Rose
authors: ER
authors: Mayeda
authors: Eric J
authors: EJ
authors: Tchetgen Tchetgen
authors: Melinda C
authors: MC
authors: Power
authors: Jennifer
authors: J
authors: Weuve
authors: Hélène
authors: H
authors: Jacqmin-Gadda
authors: Jessica R
authors: JR
authors: Marden
authors: Eric
authors: E
authors: Vittinghoff
authors: Niels
authors: N
authors: Keiding
authors: M Maria
authors: MM
authors: Glymour
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015982:Bias; D000066492:Cognitive Aging; D060825:Cognitive Dysfunction / Q000453:epidemiology* / Q000401:mortality; D003198:Computer Simulation; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D016016:Proportional Hazards Models; D015983:Selection Bias; D016019:Survival Analysis
keywords: cognitive decline; collider-stratification bias; dementia; selection bias; selective survival; simulation; survival bias; truncation by death