Age- and influenza activity-stratified case definitions of influenza-like illness: Experience from hospital-based influenza surveillance in South Korea

Tae Un Yang, Hee-Jin Cheong, Joon-Young Song, Jin Soo Lee, Seong Heon Wie, Young Keun Kim, Wonseok Choi, Jacob Lee, Hye Won Jeong, Woo Joo Kim

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10 Citations (Scopus)

Abstract

Objectives: This study aims to identify clinical case definitions of influenza with higher accuracy in patients stratified by age group and influenza activity using hospital-based surveillance system. Methods: In seven tertiary hospitals across South Korea during 2011-2012 influenza season, respiratory specimens were obtained from patients presenting an influenza-like illness (ILI), defined as having fever plus at least one of following symptoms: cough, sore throat or rhinorrhea. Influenza was confirmed by reverse transcriptase-polymerase chain reaction. We performed multivariate logistic regression analyses to identify clinical variables with better relation with laboratory-confirmed influenza, and compared the accuracy of combinations. Results: Over the study period, we enrolled 1417 patients, of which 647 had laboratory-confirmed influenza. Patients with cough, rhinorrhea, sore throat or headache were more likely to have influenza (p<0.05). The most accurate criterion across the study population was the combination of cough, rhinorrhea, sore throat and headache (sensitivity 71.3%, specificity 60.1% and AUROC 0.66). The combination of rhinorrhea, sore throat and sputum during the peak influenza activity period in the young age group showed higher accuracy than that using the whole population (sensitivity 89.3%, specificity 72.1%, and AUROC 0.81). Conclusions: The accuracy of clinical case definitions of influenza differed across age groups and influenza activity periods. Categorizing the entire population into subgroups would improve the detection of influenza patients in the hospital-based surveillance system.

Original languageEnglish
Article numbere84873
JournalPLoS One
Volume9
Issue number1
DOIs
Publication statusPublished - 2014 Jan 24

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Republic of Korea
South Korea
influenza
Human Influenza
monitoring
Pharyngitis
Polymerase chain reaction
RNA-Directed DNA Polymerase
cough
Logistics
Cough
headache
Age Groups
Headache
Population
Sensitivity and Specificity
Sputum
Reverse Transcriptase Polymerase Chain Reaction
Tertiary Care Centers
signs and symptoms (animals and humans)

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

Age- and influenza activity-stratified case definitions of influenza-like illness : Experience from hospital-based influenza surveillance in South Korea. / Yang, Tae Un; Cheong, Hee-Jin; Song, Joon-Young; Lee, Jin Soo; Wie, Seong Heon; Kim, Young Keun; Choi, Wonseok; Lee, Jacob; Jeong, Hye Won; Kim, Woo Joo.

In: PLoS One, Vol. 9, No. 1, e84873, 24.01.2014.

Research output: Contribution to journalArticle

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abstract = "Objectives: This study aims to identify clinical case definitions of influenza with higher accuracy in patients stratified by age group and influenza activity using hospital-based surveillance system. Methods: In seven tertiary hospitals across South Korea during 2011-2012 influenza season, respiratory specimens were obtained from patients presenting an influenza-like illness (ILI), defined as having fever plus at least one of following symptoms: cough, sore throat or rhinorrhea. Influenza was confirmed by reverse transcriptase-polymerase chain reaction. We performed multivariate logistic regression analyses to identify clinical variables with better relation with laboratory-confirmed influenza, and compared the accuracy of combinations. Results: Over the study period, we enrolled 1417 patients, of which 647 had laboratory-confirmed influenza. Patients with cough, rhinorrhea, sore throat or headache were more likely to have influenza (p<0.05). The most accurate criterion across the study population was the combination of cough, rhinorrhea, sore throat and headache (sensitivity 71.3{\%}, specificity 60.1{\%} and AUROC 0.66). The combination of rhinorrhea, sore throat and sputum during the peak influenza activity period in the young age group showed higher accuracy than that using the whole population (sensitivity 89.3{\%}, specificity 72.1{\%}, and AUROC 0.81). Conclusions: The accuracy of clinical case definitions of influenza differed across age groups and influenza activity periods. Categorizing the entire population into subgroups would improve the detection of influenza patients in the hospital-based surveillance system.",
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