Estimation of attributable fractions for time-to-event outcomes using an inverse probability weighted Kaplan–Meier estimator
Year: 2026
Type: article
Abstract: Population attributable fractions aim to quantify the proportion of the cases of an outcome (eg, a disease) that would have been avoided had no individuals in the population been exposed to a given exposure. This quantity thus plays a crucial role in epidemiology and public health, notably to guide policies, interventions, or to assess the burden of a disease due to a particular exposure. Various statistical methods have been proposed to estimate attributable fractions using observational data. When time-to-event data are used, several of these formulas yield invalid results. Alternative valid formulas are available but remain scarcely used. We propose a new estimator of the attributable fraction that is both conceptually simple and easy to implement using common statistical software. Our proposed estimator makes use of the Kaplan–Meier estimator to address censoring and potentially non-proportional hazards, as well as inverse probability weighting to control confounding. Non-parametric bootstrap is proposed to produce inferences. A simulation study is used to illustrate and compare our proposed estimator to several alternatives. The results showcase the bias of many commonly used traditional approaches and the validity of our estimator under its working assumptions.
Language: English
Subfield: Statistics and Probability
Field: Mathematics
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,625
OpenAlex ID: W7204125010