Academy of Medical Sciences of I.R. Iran Archives of Iranian Medicine 1029-2977 23 11 2020 11 01 Clinical Characteristics and Outcomes of 905 COVID-19 Patients Admitted to Imam Khomeini Hospital Complex in the Capital City of Tehran, Iran 766 775 10.34172/aim.2020.102 EN Seyed Farshad Allameh Saeed Nemati Reza Ghalehtaki Esmaeil Mohammadnejad Seyed Mojtaba Aghili Nasim Khajavirad Mohammad-Taghi Beigmohammadi Mohammadreza Salehi Hadi Mirfazaelian Maryam Edalatifard Hossein Kazemizadeh Seyed Ali Dehghan Manshadi Maliheh Hasannezhad Laya Amoozadeh Masoud Radnia Seyedeh Rana Khatami Azin Nahvijou Monireh Sadat Seyyedsalehi Laleh Rashidian Niloofar Ayoobi Yazdi Mohsen Nasiri Toosi Khosro Sadeghniiat-Haghighi Ali Jafarian Masud Yunesian Kazem Zendehdel https://orcid.org/0000-0002-0269-4945 Journal Article 10.34172/aim.2020.102 2020 05 11 2020 09 06 Background: We studied the clinical characteristics and outcomes of 905 hospitalized coronavirus disease 2019 (COVID-19) patients admitted to Imam Khomeini Hospital Complex (IKHC), Tehran, Iran. Methods: COVID-19 patients were recruited based on clinical symptoms and patterns of computed tomography (CT) imaging between February 20 and March 19. All patients were tested for the presence of COVID-19 RNA. The Poisson regression model estimated the incidence rate ratio (IRR) for different parameters. Results: The average age (± standard deviation) was 56.9 (±15.7) years and 61.77% were male. The most common symptoms were fever (93.59%), dry cough (79.78%), and dyspnea (75.69%). Only 43.76% of patients were positive for the RT-PCR COVID-19 test. Prevalence of lymphopenia was 42.9% and more than 90% had elevated lactate dehydrogenase (LDH) or C-reactive protein (CRP). About 11% were severe cases, and 13.7% died in the hospital. The median length of stay (LOS) was 3 days. We found higher risks of mortality in patients who were older than 70 years (IRR = 11.77, 95% CI 3.63–38.18), underwent mechanical ventilation (IRR = 7.36, 95% CI 5.06–10.7), were admitted to the intensive care unit (ICU) (IRR = 5.47, 95% CI 4.00–8.38), tested positive on the COVID-19 test (IRR = 2.80, 95% CI 1.64–3.55), and reported a history of comorbidity (IRR = 1.76, 95% CI 1.07–2.89) compared to their corresponding reference groups. Hydroxychloroquine therapy was not associated with mortality in our study. Conclusion: Older age, experiencing a severe form of the disease, and having a comorbidity were the most important prognostic factors for COVID-19 infection. Larger studies are needed to perform further subgroup analyses and verify high-risk groups.