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Multicenter Study
. 2025 Feb 25;25(1):274.
doi: 10.1186/s12879-025-10661-8.

Prognostic nutritional index as an early predictor of mortality in patients with severe fever with thrombocytopenia syndrome: multicenter retrospective study in South Korea

Hyun Ji Woo  1   2 , Tae-Kyu Kwon  3 , Sang Taek Heo  4 , Jeong Rae Yoo  4 , Misun Kim  4 , Jaeseong Oh  5 , In-Gyu Bae  6 , Sohyun Bae  7 , Young-Ran Yoon  8 , Miri Hyun  9 , Hyun Ah Kim  9 , Sook In Jung  10 , Ki Tae Kwon  11 , Soyoon Hwang  11 , Uh Jin Kim  12 , Gaeun Kang  13 , Young Jun Kim  14 , Jeong-Hwan Hwang  15 , Min-Gul Kim  16   17
Affiliations
Multicenter Study

Prognostic nutritional index as an early predictor of mortality in patients with severe fever with thrombocytopenia syndrome: multicenter retrospective study in South Korea

Hyun Ji Woo et al. BMC Infect Dis. .

Abstract

Background and aim: Severe fever with thrombocytopenia syndrome (SFTS) is a fatal tick-borne infectious disease lacking effective treatments or vaccines. Early identification of prognostic factors is essential for optimizing clinical management. This study investigated the predictors for mortality in SFTS patients.

Methods: We conducted a retrospective multicenter cohort study of 413 SFTS patients hospitalized in South Korea from 2013 to 2024. Clinical and laboratory data were comprehensively analyzed to evaluate associations between in-hospital mortality and various inflammatory, immune, and nutritional biomarkers. Cox regression and time-dependent receiver operating characteristic (ROC) analyses were performed to identify risk factors.

Results: 413 patients diagnosed with SFTS were included and In-hospital mortality was 17% (70/413). Multivariate Cox regression identified older age (HR: 1.042; 95% CI: 1.014-1.071), elevated PT(INR) (HR: 109.57; 95% CI: 19.79-606.57), and lower prognostic nutritional index (PNI) (HR: 0.937; 95% CI: 0.886-0.990) as early predictors of mortality. Time-dependent ROC analysis demonstrated predictive accuracy, with AUCs of 0.512 for age, 0.857 for PT(INR), and 0.694 for PNI at 30 days. Kaplan-Meier analysis revealed significant survival differences for patients stratified by PNI (< 40.75), PT(INR) (≥ 0.97), and age (≥ 59 years).

Conclusions: PNI, PT(INR), and age were identified as key early predictors of mortality in SFTS. PNI, as a novel biomarker, was found to be a useful index for risk level and treatment strategies in SFTS patients.

Clinical trial number: Not applicable.

Keywords: Biomarker; Early predictor; Prognostic nutritional index; Severe fever with thrombocytopenia syndrome.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: The study was approved by the institutional review board of Chonnam National University Hospital (IRB# CNUH-2023-213), Chonnam National University Hwasun Hospital (IRB# CNUH-2024-150), Gyeongsang National University Hospital (IRB# GNUH 2024-08-020), Jeju National University Hospital (IRB# JEJUNUH 2024-08-002), Jeonbuk National University Hospital (IRB# CUH 2022-01-067), Keimyung University Dongsan Hospital (IRB# DSMC 2024-08-008), Kyungpook National University Chilgok Hospital (IRB# DGIRB 2022-05-004), Kyungpook National University Hospital (IRB# DGIRB 2023-07-001), Wonkwang University Hospital (IRB# WKUH 2024-08-005). The data were kept confidential; no one except the research team had access to the files. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Study Flow Chart of Patient Selection. ‘No admission to ward’ indicates patients were seen only in the outpatient clinic or left the hospital against medical advice, providing no in-hospital follow-up data. ‘No laboratory tests within 1 day’ indicates who had no baseline lab results obtained on the day of admission or the following day
Fig. 2
Fig. 2
Kaplan-Meier Survival curves stratified by key prognostic biomarkers in patients with SFTS. Abbreviations SFTS, Severe fever with thrombocytopenia syndrome; PT(INR), prothrombin time (International Normalized Ratio); PNI, Prognostic Nutritional Index
See this image and copyright information in PMC

References

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