Clinical Course and Mortality Predictors in Adult Hospitalized Patients with COVID-19 Infection—A Retrospective Cohort Study

<i>Background and Objectives</i>: Bulgaria had the highest mortality rate of COVID-19 in Europe and the second highest in the world based on statistical data. This study aimed to determine the mortality predictors in 306 adult patients with COVID-19 infection, treated at the COVID-19 Ward of St. George University Hospital in Plovdiv, Bulgaria in the period of August 2021-April 2022. <i>Materials and Methods</i>: All admitted and treated patients had a positive PCR test for SARS-CoV-2. They were assigned in three groups based on the severity rating scale published in NIH COVID-19 Treatment Guidelines by Stat Pearls Publishing, 2022. Demographic, clinical, and laboratory parameters and pre-existing comorbidities were investigated. Parametric and non-parametric methods were used for statistics. Logistic regression was applied for parameters significantly associated with mortality. <i>Results</i>: Data showed that demographic indicators were not significantly associated with poorer outcome. Among comorbidities, cardiovascular, chronic pulmonary and endocrine disorders were found to be related to poor survival rates (<i>p</i> = 0.003, <i>p</i> = 0.003 and <i>p</i> = 0.017 resp.) Clinical symptoms, such as sore throat, dry or productive cough and breathlessness, were determinants of poor outcome (<i>p</i> = 0.027, <i>p</i> = 0.029, <i>p</i> = 0.004 and <i>p</i> = 0.002 resp.). Laboratory parameters linked to mortality were elevated d-dimers (<i>p</i> = 0.015), ferritin (<i>p</i> = 0.009) and creatinine (<i>p</i> = 0.038). p02 < 50 and saturation < 90 also indicated a higher risk of death (<i>p</i> = 0.006 and <i>p</i> = 0021). <i>Conclusions</i>: Logistic regression showed that each stage of disease severity increased the risk of death 3.6 times, chronic pulmonary disorders increased it by 4.1, endocrine by 2.4 and dyspnea by 3.1 times.