Clinical characteristics and influencing factors of severe fever with thrombocytopenia syndrome complicated by viral myocarditis: a retrospective study

This study aimed to investigate the clinical characteristics of severe fever with thrombocytopenia syndrome complicated by viral myocarditis (SFTS-VM) and analyze relevant influencing factors.

Retrospective analysis was conducted on clinical data from 79 SFTS-VM patients, categorized into common (SFTS-CVM, n = 40) and severe groups (SFTS-SVM, n = 39). Clinical manifestations, laboratory results, cardiac ultrasonography, and electrocardiogram features were analyzed. Univariate and multivariate analyses identified significant indicators, which were further assessed using ROC curves to predict SFTS-SVM.

SFTS-SVM group exhibited higher rates of hypotension, shock, abdominal pain, cough with sputum, and consciousness disorders compared to SFTS-CVM group. Laboratory findings showed elevated platelet count, ALT, AST, amylase, lipase, LDH, D-dimer, procalcitonin, TNI, and NT-proBNP in SFTS-SVM. Abnormal electrocardiograms, especially atrial fibrillation, were more prevalent in SFTS-SVM (P < 0.05). Multivariate analysis identified elevated LDH upon admission (OR = 1.004, 95% CI: 1-1.008, P = 0.050), elevated NT-proBNP (OR = 1.005, 95% CI: 1.001–1.008, P = 0.007), and consciousness disorders (OR = 112.852, 95% CI: 3.676 ~ 3464.292, P = 0.007) as independent risk factors for SFTS-SVM. LDH and NT-proBNP had AUCs of 0.728 and 0.744, respectively, in predicting SFTS-SVM. Critical values of LDH (> 978.5U/L) and NT-proBNP (> 857.5pg/ml)) indicated increased likelihood of SFTS progression into SVM.

Elevated LDH, NT-proBNP, and consciousness disorders independently correlate with SFTS-SVM. LDH and NT-proBNP can aid in early identification of SFTS-SVM development when above specified thresholds.