Research article
Understanding competing risks: a simulation point of view
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* Corresponding author: Arthur Allignol arthur.allignol@fdm.uni-freiburg.de
1 Freiburg Center for Data Analysis and Modeling, University of Freiburg, Germany
2 Institute of Medical Biometry and Medical Informatics, University Medical Center Freiburg, Germany
3 Department of Medicine 1, Division of Nephrology, University of Wuerzburg, Germany
BMC Medical Research Methodology 2011, 11:86 doi:10.1186/1471-2288-11-86
Published: 3 June 2011Abstract
Background
Competing risks methodology allows for an event-specific analysis of the single components of composite time-to-event endpoints. A key feature of competing risks is that there are as many hazards as there are competing risks. This is not always well accounted for in the applied literature.
Methods
We advocate a simulation point of view for understanding competing risks. The hazards are envisaged as momentary event forces. They jointly determine the event time. Their relative magnitude determines the event type. 'Empirical simulations' using data from a recent study on cardiovascular events in diabetes patients illustrate subsequent interpretation. The method avoids concerns on identifiability and plausibility known from the latent failure time approach.
Results
The 'empirical simulations' served as a proof of concept. Additionally manipulating baseline hazards and treatment effects illustrated both scenarios that require greater care for interpretation and how the simulation point of view aids the interpretation. The simulation algorithm applied to real data also provides for a general tool for study planning.
Conclusions
There are as many hazards as there are competing risks. All of them should be analysed. This includes estimation of baseline hazards. Study planning must equally account for these aspects.