Validation of the Rockall risk scoring system in upper gastrointestinal bleeding

Background - Several scoring systems have been developed to predict the risk of rebleeding or death in patients with upper gastrointestinal bleeding (UGIB). These risk scoring systems have not been validated in a new patient population outside the clinical context of the original study. Aims - To assess internal and external validity of a simple risk scoring system recently developed by Rockall and coworkers. Methods - Calibration and discrimination were assessed as measures of validity of the scoring system. Internal validity was assessed using an independent, but similar patient sample studied by Rockall and coworkers, after developing the scoring system (Rockall's validation sample). External validity was assessed using patients admitted to several hospitals in Amsterdam (Vreeburg's validation sample). Calibration was evaluated by a χ2 goodness of fit test, and discrimination was evaluated by calculating the area under the receiver operating characteristic (ROC) curve. Results - Calibration indicated a poor fit in both validation samples for the prediction of rebleeding (p