Abstract: International Journal of Infectious Diseases 106 (2021) 43–51 Contents lists available at ScienceDirect International Journal of Infectious Diseases journal homepage: www.elsevier.com/locate/ijid Clinical characteristics and outcomes of hospitalized COVID-19 patients in a MERS-CoV referral hospital during the peak of the pandemic Mazin Barrya,* , Nouf Althabita , Layan Akkielaha , AbdulEllah AlMohayaa,b , Muath Alotaibia , Sara Alhasania , Abdulwahab Aldreesa , Abdulaziz AlRajhia , Ali AlHijia , Fahad Almajida , Aynaa AlSharidia , Fatimah S. Al-Shahrania , Naif H. Alotaibia , Abdulkarim AlHetheelc a b c Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia Internal Medicine Department, Ad-Dariya Hospital, Ministry of Health, Riyadh, Saudi Arabia Microbiology Unit, Department of Pathology, College of Medicine, King Saud University, Riyadh, Saudi Arabia A R T I C L E I N F O A B S T R A C T Article history: Received 8 January 2021 Received in revised form 16 March 2021 Accepted 18 March 2021 Objective: To describe the clinical characteristics and outcomes of hospitalized coronavirus disease 2019 (COVID-19) patients in a middle east respiratory syndrome coronavirus (MERS-CoV) referral hospital during the peak months of the pandemic. Design: A single-center case series of hospitalized individuals with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in King Saud University Medical City (KSUMC), an academic tertiary care hospital in Riyadh, Saudi Arabia. Clinical and biochemical markers were documented. Risks for ventilatory support, intensive care unit (ICU) admission and death are presented. Results: Out of 12,688 individuals tested for SARS-CoV-2 by real time reverse transcriptase polymerase reaction (RT-PCR) from June 1 to August 31, 2020, 2,683 (21%) were positive for COVID-19. Of the latter, 605 (22%) patients required hospitalization with a median age of 55, 368 (61%) were male. The most common comorbidities were hypertension (43%) and diabetes (42%). Most patients presented with fever (66%), dyspnea (65%), cough (61%), elevated IL-6 (93.5%), D-dimer (90.1%), CRP (86.1%), and lymphopenia (41.7%). No MERS-CoV co-infection was detected. Overall, 91 patients (15%) died; risk factors associated with mortality were an age of 65 years or older OR 2.29 [95%CI 1.43–3.67], presence of two or more comorbidities OR 3.17 [95%CI 2.00–5.02], symptoms duration of seven days or less OR 3.189 [95%CI (1.64 – 6.19]) lymphopenia OR 3.388 [95%CI 2.10–5.44], high CRP OR 2.85 [95%CI 1.1–7.32], high AST OR 2.95 [95% CI 1.77–4.90], high creatinine OR 3.71 [95%CI 2.30–5.99], and high troponin-I OR 2.84 [95%CI 1.33–6.05]. Conclusion: There is a significant increase in severe cases of COVID-19. Mortality was associated with older age, shorter symptom duration, high CRP, low lymphocyte count, and end-organ damage. © 2021 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-ncnd/4.0/). Keywords: COVID-19 SARS-CoV-2 MERS-CoV Mortality