A mathematical model of case-ascertainment bias: Applied to case-control studies nested within a randomized screening trial.

ABSTRACT: When some individuals are screen-detected before the beginning of the study, but otherwise would have been diagnosed symptomatically during the study, this results in different case-ascertainment probabilities among screened and unscreened participants, referred to here as lead-time-biased case-ascertainment (LTBCA). In fact, this issue can arise even in risk-factor studies nested within a randomized screening trial; even though the screening intervention is randomly allocated to trial arms, there is no randomization to potential risk-factors and uptake of screening can differ by risk-factor strata. Under the assumptions that neither screening nor the risk factor affects underlying incidence and no other forms of bias operate, we simulate and compare the underlying cumulative incidence and

SUBMITTER: Jansen RJ 

PROVIDER: S-EPMC5858824 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature