Aim To evaluate the clinical picture and factors associated with unfavorable outcomes in admitted patients with COVID-19.Material and methods This study included all patients admitted to the COVID Center of the National Research Center of Cardiology of the Russian Ministry of Health Care from May 1 through May 31, 2020. Clinical demographic, laboratory, and instrumental indexes and associated factors were studied with one-way and multivariate logistic regression analysis.Results This study included 402 patients aged 18 to 95 years (mean age, 62.9±14.6 years); 43.0 % of them were older than 65 years. COVID-19 was frequently associated with chronic comorbidities, including arterial hypertension (74.4 %), obesity (41.6 %), history of ischemic heart disease (12.9 %), atrial fibrillation (18.9 %), type 2 diabetes mellitus (DM) (13.0 %), and oncological diseases (9.2 %). 13.0 % of patients were smokers; less than 10% had chronic lung diseases. 3.9% of patients had a combination of COVID-19 and acute coronary pathology, including acute myocardial infarction (MI) in 3.2 % (13) and unstable angina in 0.7 % (3). The most frequent clinical manifestation of COVID-19 were four symptoms: cough (81.1 %), weakness (80.3 %), shortness of breath (71.6 %), and fever (62.7 %). 46.5% of patients had shortage of breath and chest pain/compression, 40.3% had headache, 31.1% had myalgia, 28.8% had anosmia, and 25.5% had ageusia. Arterial oxygen saturation was <93.0 % in 55.7 % of cases. According to laboratory blood tests the patients had anemia (58.2 %), lymphopenia (34.8 %), neutropenia (19.2 %), thrombocytopenia (11.9 %), and increased levels of high-sensitivity C-reactive protein (hsCRP, 87.3 %), interleukin-6 (89.3 %), ferritin (62.1 %), and D-dimer (49.2 %). 56.2% of patients required various regimens of oxygen support. 83 (20.6%) patients were admitted to intensive care and resuscitation units; invasive artificial ventilation was performed only for 34 (8.5 %) patients. In-hospital mortality was 7.7 % (31 / 402). One-way regression analysis identified major factors associated with death during the stay in the hospital: age >55 years, NEWS scale score >4.0, oxygen saturation <92.0 %, blood glucose >5.4 mmol/l, hs-CRP >25.7 mg/l, and creatinine clearance <72.0 ml/min. Furthermore, the risk increased with increasing degree of changes in each factor. According to results of the multivariate regression analysis, three most significant predictors of the hard endpoint, all-cause death during the stay in the hospital, were more than 5-fold increases in aspartate aminotransferase and/or alanine aminotransferase compared to normal levels (relative risk (RR) 16.8 at 95 % confidence interval (CI) 5.0-56.3, р<0.001), pronounced changes in the lungs consistent with a CT-4 picture as shown by computed tomography (CT) (RR 13.4; 95 % CI 3.9-45.5, р<0.001), and MI/unstable angina during the stay in the hospital (RR 11.3; 95 % CI 1.4-90.6, р=0.023). The probability of death was also considerably increased by chronic obstructive pulmonary disease, impaired kidney function (creatinine clearance estimated by Cockcroft-Gault <60.0 ml/min), type 2 DM, oncological diseases, and dementia.Conclusion This study established factors associated with unfavorable outcomes in admitted patients with COVID-19. This will allow identifying in advance patients with a high risk of complications that require increased attention to take more active diagnostic and therapeutic measures at prehospital and hospital stages.