Prognostic Value of the Blood Urea Nitrogen-to-Fibrinogen Ratio for 30-Day Mortality in Patients with Severe Fever with Thrombocytopenia Syndrome: A Single-Center Retrospective Cohort Study
- 1The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230000, People’s Republic of China
Abstract
Background: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne viral disease associated with substantial mortality. Renal dysfunction and coagulation abnormalities are closely related to disease severity. This study aimed to evaluate the prognostic significance of the blood urea nitrogen-to-fibrinogen ratio (BUN/FIB) in patients with SFTS.
Methods: This single-center retrospective cohort study included adult patients with laboratory-confirmed SFTS admitted to the First Affiliated Hospital of the University of Science and Technology of China between June 2020 and June 2025. Admission BUN/FIB was calculated using BUN and fibrinogen values. Logistic regression, receiver operating characteristic (ROC) analysis, survival analysis, and paired-sample analysis were performed to evaluate the association between BUN/FIB and 30-day all-cause mortality.
Results: Of the 475 patients, 378 (79.6%) survived and 97 (20.4%) died. Admission BUN/FIB levels were significantly higher in non-survivors than in survivors. Multivariable logistic regression identified older age, neurological signs, higher C-reactive protein, higher Ct-derived SFTSV RNA burden, and higher BUN/FIB (OR: 1.565; 95% CI: 1.348–1.851; P<0.001) as independently associated with 30-day mortality. BUN/FIB showed an apparent AUC of 0.835 (95% CI: 0.791–0.880), with a cohort-derived cut-off of 3.312 mmol/g. This threshold showed a sensitivity of 78.4% and specificity of 78.0% but requires external validation. BUN/FIB showed higher apparent discrimination than conventional inflammatory indices and comparable apparent discrimination with Ct-derived SFTSV RNA burden. Higher BUN/FIB was associated with poorer survival. In paired analyses, BUN/FIB decreased among survivors and increased among non-survivors.
Conclusion: Admission BUN/FIB was independently associated with 30-day mortality and showed favorable apparent discriminatory performance in this retrospective cohort. BUN/FIB may serve as a candidate adjunctive prognostic marker, but its optimal threshold, clinical utility, and generalizability require validation in prospective multicenter studies.
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BibTeX
@article{qin2026prognostic,
title = {{Prognostic Value of the Blood Urea Nitrogen-to-Fibrinogen Ratio for 30-Day Mortality in Patients with Severe Fever with Thrombocytopenia Syndrome: A Single-Center Retrospective Cohort Study}},
author = {Ling-Han Qin and Jing Wu and Ting Liu and Ye Li and Yu-Ru Shi and Ying-Jie Qi},
journal = {Infection and Drug Resistance},
year = {2026},
month = oct,
doi = {10.2147/idr.s634788},
url = {https://doi.org/10.2147/idr.s634788},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Prognostic Value of the Blood Urea Nitrogen-to-Fibrinogen Ratio for 30-Day Mortality in Patients with Severe Fever with Thrombocytopenia Syndrome: A Single-Center Retrospective Cohort Study
AU - Ling-Han Qin
AU - Jing Wu
AU - Ting Liu
AU - Ye Li
AU - Yu-Ru Shi
AU - Ying-Jie Qi
PY - 2026
DA - 2026/10/30
JO - Infection and Drug Resistance
DO - 10.2147/idr.s634788
UR - https://doi.org/10.2147/idr.s634788
AB - Background: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne viral disease associated with substantial mortality. Renal dysfunction and coagulation abnormalities are closely related to disease severity. This study aimed to evaluate the prognostic significance of the blood urea nitrogen-to-fibrinogen ratio (BUN/FIB) in patients with SFTS. Methods: This single-center retrospective cohort study included adult patients with laboratory-confirmed SFTS admitted to the First Affiliated Hospital of the University of Science and Technology of China between June 2020 and June 2025. Admission BUN/FIB was calculated using BUN and fibrinogen values. Logistic regression, receiver operating characteristic (ROC) analysis, survival analysis, and paired-sample analysis were performed to evaluate the association between BUN/FIB and 30-day all-cause mortality. Results: Of the 475 patients, 378 (79.6%) survived and 97 (20.4%) died. Admission BUN/FIB levels were significantly higher in non-survivors than in survivors. Multivariable logistic regression identified older age, neurological signs, higher C-reactive protein, higher Ct-derived SFTSV RNA burden, and higher BUN/FIB (OR: 1.565; 95% CI: 1.348–1.851; P<0.001) as independently associated with 30-day mortality. BUN/FIB showed an apparent AUC of 0.835 (95% CI: 0.791–0.880), with a cohort-derived cut-off of 3.312 mmol/g. This threshold showed a sensitivity of 78.4% and specificity of 78.0% but requires external validation. BUN/FIB showed higher apparent discrimination than conventional inflammatory indices and comparable apparent discrimination with Ct-derived SFTSV RNA burden. Higher BUN/FIB was associated with poorer survival. In paired analyses, BUN/FIB decreased among survivors and increased among non-survivors. Conclusion: Admission BUN/FIB was independently associated with 30-day mortality and showed favorable apparent discriminatory performance in this retrospective cohort. BUN/FIB may serve as a candidate adjunctive prognostic marker, but its optimal threshold, clinical utility, and generalizability require validation in prospective multicenter studies.
SN - 1178-6973
ER -