To confirm that the Cox analysis findings were robust to potential confounders, we conducted stratified analysis by subgroups defined by covariates shown to have major roles in affecting mortality risk, including age, sex, BMI, hypertension, DM, CAD, eGFR<60, classification of HF (HFrEF, HFmrEF, or HFpEF), NYHA functional class, and quartile of NT-proBNP (Figure 4). Here, NPPB is linked to hydrops fetalis.