On multivariable analysis, Long-COVID-19 is independently and significantly correlated with D-dimer (standardized β-coefficient = 0.259), NT-ProBNP (standardized β-coefficient = 0.281), HF component of spectral analysis (standardized β-coefficient = 0.696), and LF/HF ratio (standardized β-coefficient = 0.820) (Table 4). Here, NPPB is linked to COVID-19.