3.5 Elevated BNP and Increased Mortality
The 835 severe/critical patients with BNP values recorded during hospitalization were divided into BNP high (n=171) and BNP normal (n=664) groups based on the upper reference limit (100 pg/mL). Survival analysis was conducted on two groups using applying a mixed-effect Cox model adjusted for age, sex, comorbidities, and hs-TNI, α-HBDH, CK-MB, and LDH. As a result, the BNP normal group demonstrated a significantly lower risk of mortality (Figure 6a ). The BNP level correctly classified survivors and non-survivors with an area under the curve (AUC) of 0.81 with the ideal threshold value based on the ROC curve of 62.17, a sensitivity of 71.7%, and a specificity of 80.6% (Figure 6b ).
Pearson’s correlations were used to study the association between BNP and other laboratory parameters. CRP (Figure 6c ), IL-6 (Figure 6d ), and D-dimer (Figure 6e ) showed a highly positive correlation with BNP. By contrast, BNP level was significantly negatively correlated with LYM% (Figure 6f ).