https://www.jstage.jst.go.jp/article/jea/36/4/36_JE20250126/_article

PMC

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12975769/

Highlights

• Immortal time bias comes in two forms, both leading to biased results.
• Compared three methods that use different definitions of time-zero.
• Two of these methods are subject to immortal time bias.
• Proper definition of time-zero is crucial when using non-user control groups to minimize biases in observational studies.

 Selected Result