Development and internal validation of the AGATE hybrid score for pre-endoscopic risk stratification in acute upper gastrointestinal bleeding: a single-centre, retrospective cohort study

Objective To compare five established pre-endoscopic risk scores in acute upper gastrointestinal bleeding (AUGIB) and to derive a hybrid score (Acute Gastrointestinal Bleeding ABC-GBS Triage Evaluation (AGATE)) integrating mortality prediction and triage utility. Methods We conducted a single-centre retrospective cohort study at Kayseri City Hospital, Kayseri, Türkiye, including 5000 consecutive adults with endoscopically confirmed AUGIB (January 2020–January 2025). The primary outcome was 30-day mortality; secondary outcomes were therapeutic intervention and 30-day rebleeding. Age-Blood tests-Comorbidities (ABC), Mental status-ASA class-Pulse-Albumin-Systolic blood pressure-Haemoglobin (MAP(ASH)), Haematemesis-Heart rate-Haemoglobin-Blood pressure-Blood urea nitrogen, Glasgow-Blatchford score (GBS) and Albumin, INR, Mental status, Systolic blood pressure, Age ≥65 were calculated at presentation. AGATE was derived using multivariable logistic regression for the composite end point (mortality or intervention) and internally validated with 1000 bootstrap resamples. Results Mortality was 9.2% (460/5000), intervention was required in 71.0% (3550/5000) and rebleeding occurred in 14.5% (725/5000). For mortality, ABC (area under the receiver operating characteristic curve (AUROC) 0.83, 95% CI 0.80 to 0.86) and MAP(ASH) (AUROC 0.81, 95% CI 0.78 to 0.84) demonstrated the highest discrimination; for intervention, GBS (AUROC 0.78, 95% CI 0.74 to 0.82) and MAP(ASH) (AUROC 0.77, 95% CI 0.73 to 0.80) demonstrated the highest discrimination. AGATE achieved AUROCs of 0.85 (95% CI 0.82 to 0.87) for mortality and 0.80 (95% CI 0.77 to 0.82) for intervention. For the composite end point, AGATE outperformed GBS (AUROC 0.86, 95% CI 0.83 to 0.88 vs 0.77 95% CI 0.74 to 0.80; p<0.001), with an optimism-corrected AUROC of 0.843. Using a low-risk cut-off (≤5), AGATE classified 38% (1900/5000) as low risk (0.3% mortality, 4.0% intervention), compared with 15% (750/5000) for GBS ≤1. Conclusion AGATE provides balanced pre-endoscopic triage by integrating predictors from ABC and GBS, expanding the low-risk group while maintaining very low short-term mortality. Prospective external validation in independent multicentre settings is required.