Abstract: Tohoku J. Exp. Med., 2020, 252, Evaluating 73-84 Prognostic Factors of Hospitalized COVID-19 Cases 73 Mortality Risk Factors among Hospitalized COVID-19 Patients in a Major Referral Center in Iran Nasser Malekpour Alamdari,1,* Siamak Afaghi,2,* Fatemeh Sadat Rahimi,2,* Farzad Esmaeili Tarki,2,* Sasan Tavana,3 Alireza Zali,4 Mohammad Fathi,5 Sara Besharat,6 Leyla Bagheri,2 Fatemeh Pourmotahari,6 Seyed Sina Naghibi Irvani,7 Ali Dabbagh8 and Seyed Ali Mousavi9 Department of General Surgery, Critical Care Quality Improvement Research Center, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2 Department of Internal Medicine, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran 3 Department of Pulmonary Medicine, Clinical Research and Development Center, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran 4 Functional Neurosurgery Research Center, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran 5 Department of Anesthesiology, Critical Care Quality Improvement Research Center, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran 6 Department of Radiology, Clinical Research and Development Center, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran 7 Research Institute for Endocrine Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran 8 Anesthesiology Research Center, Shahid Beheshti University of Medical Science, Tehran, Iran 9 Hematology, Oncology, and Hematopoietic Stem Cell Transplantation Research Center, Shariati Hospital, Tehran University of Medical Science, Tehran, Iran 1 The Coronavirus Disease 2019 (COVID-19) pandemic has killed many people worldwide since December 2019, and Iran has been among the most affected countries. In this retrospective study, we aimed to determine the prognostic factors associated with mortality in COVID-19 patients by analyzing 396 survived and 63 non-survived patients in Shahid Modarres Hospital, Tehran, Iran, from January 30th until April 5th, 2020. As the results, the BMI > 35 (p = 0.0003), lung cancer (p = 0.007), chronic kidney disease (p = 0.002), Immunocompromised condition (p = 0.003), and diabetes (p = 0.018) were more frequently observed in the expired group. The history of statins use was more common in the discharged group (p = 0.002), while there was no significant difference in the drug history of angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, nonsteroidal anti-inflammatory drugs, aspirin, and/or steroids, and in the past-year influenza vaccination. Multivariable regression demonstrated rising odds of in-hospital death related with age (odds ratio (OR) = 1.055, p = 0.002), levels of C-reactive protein (CRP) (OR = 2.915, p < 0.001), creatinine (OR = 1.740, p = 0.023), lymphocyte count (OR = 0.999, p = 0.008), and magnesium level (OR = 0.032, p < 0.001) on admission. In conclusion, the patients with older age and higher BMI with lymphopenia, hypomagnesemia, elevated CRP and/or raised creatinine on admission are at higher risk of mortality due to the COVID-19 infection, which requires the physicians to use timely and strong therapeutic measures for such patients. Keywords: COVID-19; Iran; prognosis; risk factor; SARS-CoV-2 Tohoku J. Exp. Med., 2020 September, 252 (1), 73-84. Received May 7, 2020; revised and accepted July 27, 2020...