Evaluation of Soluble Urokinase Plasminogen Activator Receptor in COVID-19 Patients

Background/Objectives: This retrospective study analyzed soluble urokinase plasminogen activator receptor (suPAR) plasma levels alongside routine inflammatory markers, including the neutrophil-to-lymphocyte count ratio, C-reactive protein (CRP), interleukin-6 (IL-6), procalcitonin (PCT), and D-dimers in COVID-19 patients hospitalized during the Omicron wave of the pandemic. Methods: We measured plasma suPAR levels using a suPARnostic^® Quick Triage kit. We divided COVID-19 patients into two groups based on the severity of SARS-CoV-2 infection according to the National Institutes of Health (NIH) criteria. The logistic regression analysis tested the predictive value of the biomarkers. Results: We evaluated 160 consecutive COVID-19 patients hospitalized between January and August 2022. The cohort exhibited a high incidence of comorbidities, with an in-hospital mortality rate of 5.6%. Upon admission, the median suPAR plasma levels were not significantly different between patients with mild COVID-19 (n = 110) and those with moderate/severe disease (n = 50), with 7.25 ng/mL and 7.55 ng/mL, respectively. We observed significant differences (p < 0.01) between the groups for CRP and IL-6 levels that were higher in moderate/severe disease than in mild infection. Additionally, suPAR plasma levels were above the normal range (0-2.00 ng/mL) in all patients, with a significant positive correlation identified between suPAR levels and serum IL-6, PCT, and creatinine levels. Conclusions: These findings indicate that COVID-19 during the Omicron wave is strongly associated with elevated suPAR levels; however, these levels do not directly correlate with the severity of SARS-CoV-2 infection.