Validation of a decision rule to predict patients at low risk of variceal upper gastrointestinal hemorrhage.

BACKGROUND: Determining the likelihood of a variceal versus nonvariceal source of upper gastrointestinal bleeding (UGIB) guides ED therapy, but can be difficult to determine on clinical grounds. A simple decision rule, using only platelet and international normalized ratio (INR) values, was previously derived in a single center and had high sensitivity (97%). We sought to validate this decision rule using multi-center data. MATERIALS AND METHODS: We performed this decision rule validation using data collected from 21 Canadian hospitals, comprising 2020 patients. The parent study enrolled patients aged >/=18 years at participating hospitals with nonvariceal or variceal UGIB from January 2004 through May 2005. To validate the existing decision rule, we computed the test characteristics of the rule on this study population. The existing decision rule, in order to predict patients at low risk for variceal hemorrhage, is designed to be highly sensitive for variceal UGIB. In the previously derived rule, patients are not low risk if either is present: INR >/=1.3 or platelet count