Comorbidities Associated with Worse Outcomes Among Inpatients Admitted for Acute Gastrointestinal Bleeding

Background: Multimorbidity increases healthcare resource utilization. Little is known on specific comorbidity combinations. Aims: To identify comorbidities associated with increased resource utilization among inpatients admitted for gastrointestinal bleeding (GIB). Methods: This retrospective cross-sectional study, 1/2010-5/2018 at the University Hospital Zurich, Switzerland, analyzed electronic health records of patients with upper (UGIB) and lower (LGIB) GIB, focusing on length of stay (LOS) and 30-day readmissions for resource use and clinical outcomes, investigated by multivariable regression adjusted for antithrombotics. Results: Of 1101 patients, 791 had UGIB and 310 LGIB, most often melena and bleeding diverticula, respectively. In UGIB, thromboembolic events showed a trend toward 27% increased LOS (1.27; 95% confidence interval [CI] 1.00-1.61), antithrombotics independently associated with 46% increased LOS (1.46; 95% CI 1.32-1.62). Cancer (odds ratio [OR] 2.86; 95% CI 1.68-4.88) independently associated with 30-day readmissions, anemia showed a trend (OR 1.68; 95% CI 1.00-2.84). In LGIB, none of the investigated comorbidities associated with increased LOS, but antithrombotics independently associated with 25% increased LOS (1.25; 95% CI 1.07-1.46). Atrial fibrillation/flutter (OR 2.69; 95% CI 1.06-6.82) and cancer (OR 4.76; 95% CI 1.40-16.20) associated strongly with 30-day readmissions. Conclusions: In both groups, cancer associated with 30-day readmissions, antithrombotics with increased LOS. Thromboembolic events and anemia showed clinically important trends in UGIB. Atrial fibrillation/flutter associated with 30-day readmissions in LGIB. Prospective studies are needed to investigate these complex multimorbid populations and establish appropriate guidelines