Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 50 5 2021 04 30 970 977 Biljana Bajic Health Promotion Center, Institute of Public Health Montenegro, Podgorica, Montenegro Igor Galic Center for Control and Prevention of Noncommunicable Diseases, Institute for Public Health Montenegro, Podgorica, Montenegro Natasa Mihailovic Department of Biostatistics and Informatics, Institute of Public Health Kragujevac, Kragujevac, Serbia Svetlana Ristic Institute for Oncology and Radiology of Serbia, Belgrade, Serbia Svetlana Radevic Department of Social Medicine, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia Violeta Iric Cupic Department of Internal Medicine, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia Sanja Kocic 1. Department of Biostatistics and Informatics, Institute of Public Health Kragujevac, Kragujevac, Serbia 2. Department of Social Medicine, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia Aleksandra Arnaut Department of Dentistry, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia 2021 03 29 2021 04 30 Background: Comorbidities are major predictors of in-hospital mortality in stroke patients. The Charlson comorbidity index (CCI) and the Elikhauser comorbidity index (ECI) are scoring systems for classifying comorbidities. We aimed to compare the performance of the CCI and ECI to predict in-hospital mortality in stroke patients. Methods: We included patients hospitalized for stroke in the Clinical Center of Kragujevac, Serbia for the last 7 years. Hospitalizations caused by stroke, were identified by the International Classification of Diseases-10 (ICD-10) codes I60.0 - I69.9. All patients were divided into two cohorts: Alive cohort (n=3297) and Mortality cohort (n=978). Results: There were significant associations between higher CCIS and increased risk of in-hospital mortality (HR = 1.07, 95% CI = 1.01–1.12) and between higher ECIS and increased risk of in-hospital mortality (HR = 1.04, 95% CI = 0.99–1.09). Almost 2/3 patients (66.9%) had comorbidities included in the CCI score and 1/3 patients (30.2%) had comorbidities included in the ECI score. The statistically significant higher CCI score (t = -3.88, df = 1017.96, P <0.01) and ECI score (t = -6.7, df = 1447.32, P <0.01) was in the mortality cohort. Area Under the Curve for ECI score was 0.606 and for CCI score was 0.549. Conclusion: Both, the CCI and the ECI can be used as scoring systems for classifying comorbidities in the administrative databases, but the model’s ECI Score had a better discriminative performance of in-hospital mortality in the stroke patients than the CCI Score model. https://ijph.tums.ac.ir/index.php/ijph/article/view/24348 https://ijph.tums.ac.ir/index.php/ijph/article/download/24348/7224