NPPB and pneumonia: The control group had lower serum NT-proBNP, CK, CK-MB, and C-reactive protein levels and better clinical outcomes than the myocardial injury group.<h4>Conclusions</h4>Serum hyaluronic acid, procollagen III, NTproBNP, sST2, and cfDNA significantly predict severe pneumonia complicated by myocardial damage.