Multivariate analysis, which was adjusted for age, sex, BMI, diabetes, hypertension, and serum creatinine, revealed that endocan ≥632.25 pg/mL (adjusted OR: 293.42, 95% CI: 5.65–15242.31; p = 0.005), IL-6 ≥4.19 pg/mL (adjusted OR: 26.13, 95% CI: 4.10–166.60; p = 0.001), sRAGE ≥3487.12 pg/mL (adjusted OR: 15.58, 95% CI: 2.65–91.57; p = 0.002), and syndecan-1 ≥3908.58 pg/mL (adjusted OR: 43.20, 95% CI: 4.47–417.27; p = 0.001) were associated with severe COVID-19 (Table 3). Here, SDC1 is linked to COVID-19.