TY - JOUR
T1 - Is C-reactive protein associated with influenza A or B in primary care patients with influenza-like illness?
T2 - A cross-sectional study
AU - Rystedt, Karin
AU - Harbin, Nicolay Jonassen
AU - Lindbaek, Morten
AU - Radzeviciene, Ruta
AU - Gunnarsson, Ronny
AU - Eggertsen, Robert
AU - C Butler, Christopher
AU - van der Velden, Alike W
AU - J Verheij, Theo
AU - Sundvall, Pär-Daniel
N1 - Funding Information:
AWV reports personal educational fees from Reckitt Benckiser, all outside the submitted work. TV reports grants from the NIHR, Netherlands Organization of Health Research and Development, and the EU Innovative Medicines Initiative, which has Janssen Pharmaceuticals, Biocartis, Janssen, BioMerieux, and Berry Consultants as partners, all outside the submitted work. CCB reports grants from National Institute for Health Research (NIHR) Health as NIHR Senior Investigator, grants from the NIHR Health Technology Assessment Programme to support the study, grants from NIHR Health Protection Research Unit on Health Care Associated Infections and Antimicrobial Resistance, grants from NIHR Health for the MedTech and In Vitro Diagnostics Cooperative for innovative diagnostics and monitoring technology to enhance Community Healthcare during the conduct of the study, personal fees from Pfizer and Roche Molecular Systems, grants from Roche Molecular Diagnostics, all outside the submitted work. All other authors declare no competing interests.
Funding Information:
The main study ALIC4E was supported by the European Commission FP7 Programme. The Healthcare Committee, Region Västra Götaland, Sweden, partially funded the Swedish part of the study. The Antibiotic Centre for primary Care, University of Oslo partially funded the Norwegian part of the study. The authors thank the patients and the participating primary health care centres who participated in this study.
Publisher Copyright:
© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
PY - 2020/12
Y1 - 2020/12
N2 - Objective: Identifying influenza A or B as cause of influenza-like illness (ILI) is a challenge due to non-specific symptoms. An accurate, cheap and easy to use biomarker might enhance targeting influenza-specific management in primary care. The aim of this study was to investigate if C-reactive protein (CRP) is associated with influenza A or B, confirmed with PCR testing, in patients presenting with ILI. Design: Cross-sectional study. Setting: Primary care in Lithuania, Norway and Sweden. Subjects: A total of 277 patients at least 1 year of age consulting primary care with ILI during seasonal influenza epidemics. Main outcome measures: Capillary blood CRP analysed as a point-of-care test and detection of influenza A or B on nasopharyngeal swabs in adults, and nasal and pharyngeal swabs in children using PCR. Results: The prevalence of positive tests for influenza A among patients was 44% (121/277) and the prevalence of influenza B was 21% (58/277). Patients with influenza A infection could not be identified based on CRP concentration. However, increasing CRP concentration in steps of 10 mg/L was associated with a significantly lower risk for influenza B with an adjusted odds ratio of 0.42 (0.25–0.70; p<.001). Signs of more severe symptoms like shortness of breath, sweats or chills and dizziness were associated with higher CRP. Conclusions: There was no association between CRP and influenza A. Increased concentration of CRP was associated with a lower risk for having influenza B, a finding that lacks clinical usefulness. Hence, CRP testing should be avoided in ILI, unless bacterial pneumonia is suspected.Key points Identifying influenza A or B as cause of influenza-like illness (ILI) is a challenge due to non-specific symptoms. There was no association between concentration of CRP and influenza A. Increased concentration of CRP was associated with a lower risk for having influenza B, a finding that lacks clinical usefulness. A consequence is that CRP testing should be avoided in ILI, unless bacterial pneumonia or similar is suspected.
AB - Objective: Identifying influenza A or B as cause of influenza-like illness (ILI) is a challenge due to non-specific symptoms. An accurate, cheap and easy to use biomarker might enhance targeting influenza-specific management in primary care. The aim of this study was to investigate if C-reactive protein (CRP) is associated with influenza A or B, confirmed with PCR testing, in patients presenting with ILI. Design: Cross-sectional study. Setting: Primary care in Lithuania, Norway and Sweden. Subjects: A total of 277 patients at least 1 year of age consulting primary care with ILI during seasonal influenza epidemics. Main outcome measures: Capillary blood CRP analysed as a point-of-care test and detection of influenza A or B on nasopharyngeal swabs in adults, and nasal and pharyngeal swabs in children using PCR. Results: The prevalence of positive tests for influenza A among patients was 44% (121/277) and the prevalence of influenza B was 21% (58/277). Patients with influenza A infection could not be identified based on CRP concentration. However, increasing CRP concentration in steps of 10 mg/L was associated with a significantly lower risk for influenza B with an adjusted odds ratio of 0.42 (0.25–0.70; p<.001). Signs of more severe symptoms like shortness of breath, sweats or chills and dizziness were associated with higher CRP. Conclusions: There was no association between CRP and influenza A. Increased concentration of CRP was associated with a lower risk for having influenza B, a finding that lacks clinical usefulness. Hence, CRP testing should be avoided in ILI, unless bacterial pneumonia is suspected.Key points Identifying influenza A or B as cause of influenza-like illness (ILI) is a challenge due to non-specific symptoms. There was no association between concentration of CRP and influenza A. Increased concentration of CRP was associated with a lower risk for having influenza B, a finding that lacks clinical usefulness. A consequence is that CRP testing should be avoided in ILI, unless bacterial pneumonia or similar is suspected.
KW - C-reactive protein
KW - influenza in humans
KW - point-of-care testing
KW - primary health care
KW - respiratory tract infections
UR - http://www.scopus.com/inward/record.url?scp=85096185429&partnerID=8YFLogxK
U2 - 10.1080/02813432.2020.1843942
DO - 10.1080/02813432.2020.1843942
M3 - Article
C2 - 33174788
SN - 0281-3432
VL - 38
SP - 447
EP - 453
JO - Scandinavian Journal of Primary Health Care
JF - Scandinavian Journal of Primary Health Care
IS - 4
ER -