Acute Myocardial Injury in Patients Presenting With Upper Gastrointestinal Bleeding: Prevalence, Predictors, Troponin Dynamics, and In-Hospital Outcomes

Background: Upper gastrointestinal bleeding (UGIB) may cause anemia, hypovolemia, and hemodynamic compromise, potentially contributing to myocardial injury during the acute illness. Troponin elevation in this setting requires careful interpretation because an isolated measurement cannot reliably distinguish acute injury from elevation without qualifying change or establish myocardial infarction. The frequency, temporal evolution, and clinical significance of acute myocardial injury in patients with UGIB remain incompletely characterized. This prospective multicenter study evaluated its prevalence, associated admission factors, serial troponin dynamics, and relationship with in-hospital outcomes, including subsequent mortality among patients surviving the first 24 hours. Methods: This prospective multicenter observational cohort study enrolled 1,000 adults at tertiary care hospitals in Punjab, Pakistan, between January 2025 and August 2026. Cardiac troponin I measurements were scheduled at presentation, 3-6 hours, and 20-24 hours. Acute injury required a concentration above the applicable 99th-percentile reference limit and a serial maximum-minimum range of ≥10 ng/L and ≥20% of the earliest observed concentration, using at least two measurements spanning ≥3 hours. Prevalence was estimated with Wilson confidence intervals (CIs). Multivariable logistic regression examined admission factors associated with injury. A 24-hour landmark analysis evaluated subsequent mortality among patients alive and still hospitalized with classifiable injury status. Results: Injury status was classifiable in 960 patients; 104 had acute injury, giving a prevalence of 10.8% (95% CI: 9.0-13.0%). A further 131 patients (13.6% of classifiable assessments) had troponin elevation without qualifying change, while 40 assessments were indeterminate. Older age (adjusted odds ratio (aOR) per decade: 1.40; 95% CI: 1.21-1.63), coronary artery disease (aOR: 1.82; 95% CI: 1.06-3.10), and lower hemoglobin (aOR per 1 g/dL decrease: 1.27; 95% CI: 1.06-1.51) were associated with acute injury. Fourteen acute-injury cases (13.5%) first met the classification criterion at the late measurement. Among 810 landmark patients with known outcomes, 34 died. Subsequent mortality was 15.2% with acute injury versus 2.8% without acute injury (aOR: 3.47; 95% CI: 1.58-7.62; p=0.002). An adverse differential assignment of unresolved mortality outcomes attenuated this association (aOR: 1.86; 95% CI: 0.94-3.69). Conclusions: Acute myocardial injury affected approximately one in 10 classifiable patients with UGIB and was associated with older age, coronary artery disease, lower hemoglobin, and higher subsequent in-hospital mortality. Serial measurements distinguished acute changes from elevation without qualifying change. The mortality association requires cautious interpretation because of limited events, residual confounding, and incomplete follow-up.