SARS-CoV-2 continues to pose a major challenge to scientists and clinicians. We examined the significance of the serum concentrations of vitamin D, albumin, and D-dimer for the severity of the clinical picture and mortality in COVID-19. Materials and methods: A total of 288 patients treated for COVID-19 infection participated in the research. The patients were treated in the period from May 2020 to January 2021. All patients were divided based on the need for oxygen therapy (Sat > 94%) into patients with mild or severe clinical pictures. The biochemical and radiographic parameters of the patients were analyzed. Appropriate statistical methods were used in the statistical analysis. Results: In patients with COVID-19 with confirmed severe clinical pictures, lower values of serum albumin (p < 0.0005) and vitamin D (p = 0.004) were recorded, as opposed to elevated values of D-dimer (p < 0.0005). Accordingly, the patients with fatal disease outcomes had lower levels of albumin (p < 0.0005) and vitamin D (p = 0.002), while their D-dimer (p < 0.0005) levels were elevated. An increase in the radiographic score, as a parameter for assessing the severity of the clinical picture, was accompanied by a decrease in serum albumin (p < 0.0005) and a simultaneous increase in D-dimer (p < 0.0005), without a change in the vitamin D concentration (p = 0.261). We also demonstrated the interrelations of the serum levels of vitamin D, albumin, and D-dimer in patients with COVID-19 as well as their significance as predictors of the outcome of the disease. Conclusion: The significance of the predictive parameters in our study indicates the existence of an important combined role of vitamin D, albumin, and D-dimer in the early diagnosis of the most severe patients suffering from COVID-19. Reduced values of vitamin D and albumin, in combination with elevated values of D-dimer, can be timely indicators of the development of a severe clinical picture and death due to COVID-19.

Background/Aim. COVID 19 is a predominantly respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The aim of this study was to determine whether there are significant variables which could predict severe clinical picture and fatal outcome in COVID 19 patients. Methods. The research involved 632 patients who were treated at the University Medical Center Kragujevac at the Clinic for Infectious Diseases, in the period from June 2020 to February 2021. All patients were divided into two groups according to the need for oxygen therapy (Sat 02 < 94. Results. Our results showed that high BMI was singled out as a risk factor for the development of a severe clinical picture [BMI [ORadjusted = 1.263; 95% CI = 1.117 - 1.427; p < 0.001]]. Prothrombin time (ORadjusted = 1.170; 95% CI = 1.004 - 1.364; p = 0.045), as well as low albumin values (ORadjusted = 0.878; 95% CI = 0.804 - 0.958; p = 0,003) had a predictive significance for the development of severe clinical picture. Factors that were of predictive importance in patients with fatal outcome were CRP (ORadjusted = 1.010; 95% CI = 1.001 - 1.019; p = 0.031), LDH (ORadjusted = 1.004; 95% CI = 1.001 - 1.006; p = 0.002). X-ray of the lungs (ORadjusted = 1.394; 95% CI = 1.170 - 1.661; p < 0.001). Conclusion. Research has shown that routine, clinical-laboratory parameters can be important in the early detection of patients with a potentially severe clinical picture and fatal outcome. In patients with a mild clinical picture, CRP, LDH, ferritin, and serum albumin levels may indicate timely disease progression. Monitoring of parameters of essential importance for the timely clinical assessment of patients with COVID 19, and thus the timely application of adequate therapeutic protocols in the treatment of these patients.