Supplementary Material for: Comparison of pre-endoscopic C-WATCH score with established risk assessment tools in patients with upper gastrointestinal bleeding

Background: Use of risk scores for early assessment of patients with upper gastrointestinal bleeding (UGIB) is recommended by various guidelines. We compared C-WATCH score with Glasgow Blatchford Score (GBS), Rockall score (RS) and pre-endoscopic RS (p-RS). Methods: Patients with UGIB between January to December 2017 were retrospectively analyzed regarding 30 day-mortality and composite endpoints risk of complications and need for intervention using areas under the receiver operating characteristics curve (AUROC). Subgroup analysis was conducted for patients with UGIB on admission and in-hospital UGIB. Results: 252 patients were identified (67.5% men, mean age 63.8±14.9 years). In-hospital UGIB occurred in 49.6%. AUROCs for 30 day-mortality, risk of complications and need for intervention (not applicable to RS) were 0.684 (95%-CI 0.606-0.763), 0.665 (95%-CI 0.594-0.735) and 0.694 (95%-CI 0.612-0.775) for C-WATCH score, 0.724 (95%-CI 0.653-0.796) and 0.751 (95%-CI 0.687-0.815) for RS, 0.652 (95%-CI 0.57-0.735), 0.653 (95%-CI 0.579-0.727) and 0.673 (95%-CI 0.602-0.745) for p-RS and 0.652 (95%-CI 0.572-0.732), 0.663 (95%-CI 0.592-0.734) and 0.752 (95%-CI 0.683-0.821) for GBS. RS outperformed pre-endoscopic scores in predicting risk of complications, while there were no significant differences between pre-endoscopic scores except GBS outperforming p-RS in predicting need for intervention. The subgroup analysis obtained similar results. Positive predictive values for patients with estimated low risk for all three endpoints (C-WATCH score ≤1, RS ≤2, p-RS <1 and GBS ≤1) were 89%, 69%, 78% and 92%. Conclusion: C-WATCH score performed similar to established pre-endoscopic risk scores in patients with UGIB regarding relevant patient related endpoints with no significant differences between both subgroups.