The Shock Index is not accurate at predicting outcomes in patients with upper gastrointestinal bleeding

Background Acute upper gastrointestinal bleeding (UGIB) remains a major cause of hospital admission worldwide. The recent UK National Confidential Enquiry into Patient Outcome and Death (NCEPOD) report on UGIB suggested use of the Shock Index to identify patients at risk of a poor outcome after UGIB. However, this has never been prospectively validated as a predictor of outcome in UGIB. Aims To compare the Shock Index with existing pre-endoscopic UGIB risk scores in predicting outcomes after UGIB Methods In an international, prospective study of 3012 consecutive patients with UGIB, we compared the Shock Index with existing scores including the Glasgow Blatchford score (GBS), admission Rockall score, AIMS65, and the newly described "ABC" score. Pre-determined endpoints were need for major (>= 4 units red cells) transfusion, need for endoscopic therapy and 30-day mortality. Results The Shock Index was inferior to the GBS in predicting need for major transfusion (area under the receiver operator characteristic curve [AUROC] 0.655 vs 0.836, P < 0.001) and need for endotherapy (AUROC 0.606 vs 0.747, P < 0.001). The Shock Index was inferior to all other scores for 30-day mortality: for example, AUROC 0.611 vs 0.863 for ABC score (P < 0.001). Adding the Shock Index to the ABC score did not improve accuracy of the ABC score in predicting mortality (AUROC 0.864 vs 0.863, P = 0.95). Conclusion The Shock Index performed poorly with AUROCs <0.66 and was inferior to existing pre-endoscopy scores at predicting major clinical endpoints after UGIB. Despite the NCEPOD suggestion, we found no clear evidence that the Shock Index is clinically useful at predicting outcomes in UGIB.