Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 11 3 2025 01 30 277 284 Parisa Kianpour Anesthesia, Critical Care and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Mohammad Hossein Hajali Student Research Committee, AJA University of Medical Sciences, Tehran, Iran‎. Hamidreza Karbalaei-Musa Student Research Committee, AJA University of Medical Sciences, Tehran, Iran‎. Reza Mourtami Anesthesia, Critical Care and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. & School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran. Reza Pourfallah Anesthesia, Critical Care and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Atabak Najafi Department of Anesthesia and Intensive Care‎, Sina Hospital‎, Tehran University of Medical Sciences, Tehran, ‎Iran. Mojtaba Mojtahedzadeh Anesthesia, Critical Care and Pain Management Research Center, Tehran University of Medical Sciences, Tehran, Iran. Samrand Fattah Ghazi Department of Anesthesiology and Critical Care‎, Imam Khomeini Hospital Complex‎, Tehran University of Medical Sciences, Tehran, ‎Iran. Arezoo Ahmadi Department of Anesthesia and Intensive Care‎, Sina Hospital‎, Tehran University of Medical Sciences, Tehran, ‎Iran. Nasibe Ashouri Department of Critical Care, Imam Khomeini Hospital Complex‎, Tehran University of Medical Sciences, Tehran, ‎Iran. Babak Jahangirifard Department of Anesthesia and Intensive Care‎, School of Medicine‎, Aja University of Medical Sciences, Tehran, ‎Iran. 2024 10 13 2024 11 12 Background: This study aimed to investigate mortality risk factors among severe COVID-19 patients admitted to the intensive care unit (ICU) to inform better management strategies and reduce mortality rates. Methods: A descriptive-analytical, cross-sectional, and retrospective study was conducted between March 2022 and April 2023 at the intensive care unit of Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran. The study included patients admitted to the ICU with severe COVID-19. The main variables were demographic factors (age, gender), pre-existing medical conditions (smoking, diabetes, hypertension), disease severity markers (CT-scan scores, inflammatory and coagulation parameters), and mortality outcomes. Results: The study included 395 eligible patients. The mortality rate was 57.72%, with no significant difference in hospital stay duration between deceased and survived patients. Smoking, diabetes mellitus, and hypertension were significantly associated with higher mortality. Males exhibited a higher mortality rate, although not statistically significant. Patients over 65 years old had significantly higher mortality. Winter showed a significant increase in mortality, likely due to the Omicron subvariant. Higher CT scan scores and elevated inflammatory/coagulation markers correlated with increased mortality risk. Conclusion: Pre-existing conditions, demographic factors, and disease severity markers are crucial predictors of mortality in severe COVID-19 patients. Tailored interventions targeting these risk factors are essential to improve outcomes. https://aacc.tums.ac.ir/index.php/aacc/article/view/1108