Hematological Markers in Thromboembolic Events: A Comparative Study of COVID-19 and Non-COVID-19 Hospitalized Patients

<b>Background/Objectives</b>: SARS-CoV-2 infection increases thrombotic events in hospitalized patients, especially those of greater severity. It has been associated with the cytokine storm and worsening renal and liver function, increased inflammatory markers, and altered coagulation markers. This study analyzes differences in inflammatory, hepatic, renal, and coagulation markers between hospitalized patients with and without COVID-19 who experienced thromboembolic events during the last three years of the pandemic. <b>Methods</b>: This single-center, retrospective observational study, with an inferential component and biomarker analysis, included 663 patients (600 without COVID-19, 63 with COVID-19) admitted between December 2022 and January 2023. <b>Results</b>: Patients with COVID-19 exhibited significantly higher mean glomerular filtration rate (GFR) (100.5 mL/min/1.73 m²; <i>p</i> < 0.01) and alanine aminotransferase (ALT) levels (33.0 IU/L; <i>p</i> < 0.01) compared to those without COVID-19. Ferritin levels were also significantly elevated in COVID-19 patients (441.1; <i>p</i> < 0.01), particularly those with severe disease. Conversely, troponin I was significantly higher in patients without COVID-19 (22.6 × 10⁴ pg/mL; <i>p</i> < 0.001). Among COVID-19 patients, D-dimer levels were significantly higher in those not requiring intensive care unit (ICU) admission (9.0 × 10³ ng/mL; <i>p</i> = 0.023). Multivariate analysis revealed a significant association between COVID-19 and sex. <b>Conclusions</b>: Overall, renal function did not differ significantly between COVID-19 and non-COVID-19 patients. However, renal function was better in patients admitted to the ICU, regardless of COVID-19 status. Troponin I levels were elevated in non-COVID-19 patients, while ferritin and ALT levels were higher in COVID-19 patients. D-dimer levels showed no significant difference between the two groups.