Aims. To consider factors associated with adverse outcome among hospitalized patients with moderate and severe COVID-19.Materials and methods. Data from 345 case histories of adult patients hospitalized with moderate to severe COVID-19 were analyzed in a single-center retrospective study. Characteristics by sex, age, number of days from disease onset to admission to hospital, duration of hospitalization, duration of disease, population characteristics by medical history of comorbidities and self-medication, outcome of hospitalization and medical technologies used in hospital conditions were given for the whole cohort of patients. All parameters were analyzed using descriptive statistics methods. Qualitative variables are given in absolute (n) and relative (%) values with 95% confidence interval. Continuous variables were presented as median and quartiles. Risk factors for mortality were determined across groups using the χ2 criterion and odds ratio.Results. There was no demonstrated effect of gender, degree of pulmonary tissue lesions on computed tomography data, or time of initiation of respiratory support on disease outcome. At the same time, the age older than 65 years as well as neoplasms, type 2 diabetes mellitus, dementia, Stage 3 arterial hypertension, chronic heart failure, coronary heart disease, myocardial infarction and stroke history, chronic obstructive pulmonary disease, bronchiectatic disease, urogenital diseases were the predictors of unfavorable outcome in patients with moderate and severe COVID-19 form. Prehospital use of antiplatelet agents, direct and indirect oral anticoagulants, drugs affecting the renin-angiotensin system, systemic glucocorticosteroids, antibiotics, antiviral drugs, and analgesics was associated with a decrease in the mortality rate in patients with moderate-to-severe COVID-19, as well as timely use of pronposition and transfer to intensive care unit.Conclusions. Our findings are partially consistent with previous reports on the effect of risk factors on COVID-19 outcomes.