Lactate Dehydrogenase/Albumin to Urea Ratio: A Novel Prognostic Indicator for Adverse Outcomes in Patients With Severe Fever With Thrombocytopenia Syndrome.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with significant mortality risks. This study evaluated the predictive value of the lactate dehydrogenase/albumin to urea ratio (LAU) for lethal outcomes in SFTS patients. Clinical data from 348 patients (295 survivors, 53 non-survivors) admitted to Yantai Infectious Disease Hospital (2022-2023) were analyzed. Multivariate analysis identified older age, SFTS-associated encephalopathy, SFTSV RNA, decreased albumin and serum calcium, increased lactate dehydrogenase, and elevated LAU as independent mortality risk factors. LAU demonstrated strong predictive accuracy (AUC: 0.79; 95% CI: 0.72-0.85; sensitivity 69%, specificity 75%), with an optimal cutoff of 144.685 U·mmol/g·L. Survival analysis linked high LAU to poor prognosis, and longitudinal trends showed decreasing LAU with recovery in survivors but rising levels in non-survivors. These findings highlight LAU as a novel, practical biomarker for early risk stratification and prognosis improvement in SFTS.