J Korean Med Sci.  2020 Mar;35(11):e77. 10.3346/jkms.2020.35.e77.

Clinical Score System to Differentiate Severe Fever with Thrombocytopenia Syndrome Patients from Patients with Scrub Typhus or Hemorrhagic Fever with Renal Syndrome in Korea

• Heo DH
• Kang YM
• Song KH
• Seo JW
• Kim JH
• Chun JY
• Jun KI
• Kang CK
• Moon SM
• Choe PG
• Park WB
• Bang JH
• Kim ES
• Kim HB
• Park SW
• Oh WS
• Kim NJ
• Oh MD

• KMID: 2471793
• DOI: http://doi.org/10.3346/jkms.2020.35.e77

Abstract

BACKGROUND
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with high mortality in East Asia. This study aimed to develop, for primary care providers, a prediction score using initial symptoms and basic laboratory blood tests to differentiate between SFTS and other endemic zoonoses in Korea.
METHODS
Patients aged ≥ 18 years diagnosed with endemic zoonoses during a 3-year period (between January 2015 and December 2017) were retrospectively enrolled from 4 tertiary university hospitals. A prediction score was built based on multivariate logistic regression analyses.
RESULTS
Of 84 patients, 35 with SFTS and 49 with other endemic zoonoses were enrolled. In multivariate logistic regression analysis, independent predictors of SFTS included neurologic symptoms (odds ratio [OR], 12.915; 95% confidence interval [CI], 2.173-76.747), diarrhea (OR, 10.306; 95% CI, 1.588-66.895), leukopenia (< 4,000/mm3) (OR, 19.400; 95% CI, 3.290-114.408), and normal C-reactive protein (< 0.5 mg/dL) (OR, 24.739; 95% CI, 1.812-337.742). We set up a prediction score by assigning one point to each of these four predictors. A score of ≥ 2 had 82.9% sensitivity (95% CI, 71.7%-87.5%) and 95.9% specificity (95% CI, 88.0%-99.2%). The area under the curve of the clinical prediction score was 0.950 (95% CI, 0.903-0.997).
CONCLUSION
This study finding suggests a simple and useful scoring system to predict SFTS in patients with endemic zoonoses. We expect this strategic approach to facilitate early differentiation of SFTS from other endemic zoonoses, especially by primary care providers, and to improve the clinical outcomes.

Keyword

Severe Fever with Thrombocytopenia Syndrome; Prediction; Differential Diagnosis; Scrub Typhus; Hemorrhagic Fever with Renal Syndrome

MeSH Terms

C-Reactive Protein
Communicable Diseases, Emerging
Diagnosis, Differential
Diarrhea
Far East
Fever*
Hematologic Tests
Hemorrhagic Fever with Renal Syndrome*
Hospitals, University
Humans
Korea*
Leukopenia
Logistic Models
Mortality
Neurologic Manifestations
Primary Health Care
Retrospective Studies
Scrub Typhus*
Sensitivity and Specificity
Thrombocytopenia*
Zoonoses
C-Reactive Protein