Seyed Farshad Allameh
1, Saeed Nemati
2, Reza Ghalehtaki
3,4, Esmaeil Mohammadnejad
5, Seyed Mojtaba Aghili
6, Nasim Khajavirad
7, Mohammad-Taghi Beigmohammadi
8, Mohammadreza Salehi
9, Hadi Mirfazaelian
8, Maryam Edalatifard
10,11, Hossein Kazemizadeh
10,11, Seyed Ali Dehghan Manshadi
9, Maliheh Hasannezhad
9, Laya Amoozadeh
8, Masoud Radnia
7, Seyedeh Rana Khatami
11, Azin Nahvijou
2, Monireh Sadat Seyyedsalehi
2, Laleh Rashidian
12, Niloofar Ayoobi Yazdi
13, Mohsen Nasiri Toosi
14, Khosro Sadeghniiat-Haghighi
15, Ali Jafarian
14,16, Masud Yunesian
17,18, Kazem Zendehdel
2,19,20* 
1 Gastroenterology Ward, Imam Khomeini Hospital Complex (IKHC), Tehran University of Medical Sciences, Tehran, Iran
2 Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran
3 Department of Radiation Oncology, Cancer Institute, Imam Khomeini Hospital Complex (IKHC), Tehran University of Medical Sciences, Tehran, Iran
4 Radiation Oncology Research Center, Cancer Research Institute, Tehran University of Medical Sciences, Tehran, Iran
5 Department of Medical-Surgical Nursing and Basic Sciences, School of Nursing and Midwifery, Tehran University of Medical Sciences, Tehran, Iran
6 Department of Emergency Medicine, Imam Khomeini Hospital Complex (IKHC), Tehran University of Medical Sciences, Tehran, Iran
7 Department of Internal Medicine, Imam Khomeini Hospital Complex (IKHC), Tehran University of Medical Sciences, Tehran, Iran
8 Department of Anesthesiology and Intensive Care, Imam Khomeini Hospital Complex (IKHC), Tehran University of Medical Sciences, Tehran, Iran
9 Department of Infectious Diseases and Tropical Medicine, Imam Khomeini Hospital Complex (IKHC), Tehran University of Medical Sciences, Tehran, Iran
10 Department of Pulmonology, Imam Khomeini Hospital Complex (IKHC), Tehran University of Medical Sciences, Tehran, Iran
11 Thoracic Research Center, Tehran University of Medical Sciences, Tehran, Iran
12 Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
13 Department of Radiology, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran
14 Liver Transplantation Research Center, Tehran University of Medical Sciences, Tehran, Iran
15 Occupational Sleep Research Center, Tehran University of Medical Sciences, Tehran, Iran
16 Hepatobiliary Surgery and Liver Transplantation Division, Department of General Surgery, Imam Khomeini Hospital Complex, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
17 Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
18 Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran
19 Cancer Biology Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran
20 Breast Diseases Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran
Abstract
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.