When to Censor?

4 years ago

When to Censor?

Cole, Edwards, Lau, Moore, Lesko

Loss to follow-up is an endemic feature of time-to-event analyses that precludes observation of the event of interest. To our knowledge, in typical cohort studies with encounters occurring at regular or irregular intervals, there is no consensus on how to handle person-time between participants' last study encounter and when they meet a definition of loss to follow-up. We demonstrate, using simulation and an example, that when the event of interest is captured outside of a study encounter (e.g., in a registry) person-time should be censored when the study-defined criterion for loss to follow-up is met (e.g., one year after last encounter), rather than at the last study encounter. Conversely, when the event of interest must be measured within the context of a study encounter (e.g., a biomarker value) person-time should be censored at the last study encounter. An inappropriate censoring scheme has the potential to result in substantial bias that may not be easily corrected.

Publisher URL: http://doi.org/10.1093/aje/kwx281

DOI: 10.1093/aje/kwx281