Removal of ineligible outcome cases reduces confounding.

ABSTRACT:

Background

When an exclusionary criterion is an imperfect screen, some ineligible patients will remain in a study. Medical record review for outcome adjudication can reveal such individuals.

Objective

To ascertain the circumstances under which it is advisable to remove outcome cases first found to be ineligible on chart review.

Methods

The impact on the relative risk caused by removal of ineligible outcome cases was examined under different circumstances of confounding, prevalence, and efficacy of the screening criterion for exclusions. The result is illustrated by a hospital-based cohort study in which electronic medical record diagnosis served to exclude ineligible cases, and review of text notes for putative outcome cases revealed that the codes were only 95% sensi

SUBMITTER: Walker AM 

PROVIDER: S-EPMC5973633 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature