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Use of serum C reactive protein and procalcitonin concentrations in addition to symptoms and signs to predict pneumonia in patients presenting to primary care with acute cough: diagnostic study

Use of serum C reactive protein and procalcitonin concentrations in addition to symptoms and signs to predict pneumonia in patients presenting to primary care with acute cough: diagnostic study
Use of serum C reactive protein and procalcitonin concentrations in addition to symptoms and signs to predict pneumonia in patients presenting to primary care with acute cough: diagnostic study
OBJECTIVES: To quantify the diagnostic accuracy of selected inflammatory markers in addition to symptoms and signs for predicting pneumonia and to derive a diagnostic tool.

DESIGN: Diagnostic study performed between 2007 and 2010. Participants had their history taken, underwent physical examination and measurement of C reactive protein (CRP) and procalcitonin in venous blood on the day they first consulted, and underwent chest radiography within seven days.

SETTING: Primary care centres in 12 European countries.

PARTICIPANTS: Adults presenting with acute cough.

MAIN OUTCOME MEASURES: Pneumonia as determined by radiologists, who were blind to all other information when they judged chest radiographs.

RESULTS: Of 3106 eligible patients, 286 were excluded because of missing or inadequate chest radiographs, leaving 2820 patients (mean age 50, 40% men) of whom 140 (5%) had pneumonia. Re-assessment of a subset of 1675 chest radiographs showed agreement in 94% (? 0.45, 95% confidence interval 0.36 to 0.54). Six published "symptoms and signs models" varied in their discrimination (area under receiver operating characteristics curve (ROC) ranged from 0.55 (95% confidence interval 0.50 to 0.61) to 0.71 (0.66 to 0.76)). The optimal combination of clinical prediction items derived from our patients included absence of runny nose and presence of breathlessness, crackles and diminished breath sounds on auscultation, tachycardia, and fever, with an ROC area of 0.70 (0.65 to 0.75). Addition of CRP at the optimal cut off of >30 mg/L increased the ROC area to 0.77 (0.73 to 0.81) and improved the diagnostic classification (net reclassification improvement 28%). In the 1556 patients classified according to symptoms, signs, and CRP >30 mg/L as "low risk" (<2.5%) for pneumonia, the prevalence of pneumonia was 2%. In the 132 patients classified as "high risk" (>20%), the prevalence of pneumonia was 31%. The positive likelihood ratio of low, intermediate, and high risk for pneumonia was 0.4, 1.2, and 8.6 respectively. Measurement of procalcitonin added no relevant additional diagnostic information. A simplified diagnostic score based on symptoms, signs, and CRP >30 mg/L resulted in proportions of pneumonia of 0.7%, 3.8%, and 18.2% in the low, intermediate, and high risk group respectively.

CONCLUSIONS: A clinical rule based on symptoms and signs to predict pneumonia in patients presenting to primary care with acute cough performed best in patients with mild or severe clinical presentation. Addition of CRP concentration at the optimal cut off of >30 mg/L improved diagnostic information, but measurement of procalcitonin concentration did not add clinically relevant information in this group.
0959-8138
f2450
van Vugt, Saskia F.
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Broekhuizen, Berna D.L.
58780c58-a133-4b22-ab3d-b30261859a62
Lammens, Christine
5c95854e-7ed4-4932-a4c1-55c3555d5bb5
Zuithoff, Nicolaas P.A.
1b152e26-e7c7-4b88-b231-26c410726393
de Jong, Pim A.
79dc7043-2e95-409e-8e47-5598bf915f3a
Coenen, Samuel
3d0dc4e0-e5ba-4d66-ba92-15900ccc551e
Ieven, Margareta
c138048d-d838-4c8e-848d-a43e309f4cf0
Butler, Chris C.
cedab343-9e0c-420f-ba80-f2f824969687
Goossens, Herman
31f8e1ae-7da0-473c-bd49-f911c2187451
Little, Paul
1bf2d1f7-200c-47a5-ab16-fe5a8756a777
Verheij, Theo J.M.
817a26b8-7db9-4e79-b00e-c0457f19f236
Moore, Michael
1be81dad-7120-45f0-bbed-f3b0cc0cfe99
GRACE Consortium
van Vugt, Saskia F.
3e57440e-03ab-4f82-828a-9e80441ed081
Broekhuizen, Berna D.L.
58780c58-a133-4b22-ab3d-b30261859a62
Lammens, Christine
5c95854e-7ed4-4932-a4c1-55c3555d5bb5
Zuithoff, Nicolaas P.A.
1b152e26-e7c7-4b88-b231-26c410726393
de Jong, Pim A.
79dc7043-2e95-409e-8e47-5598bf915f3a
Coenen, Samuel
3d0dc4e0-e5ba-4d66-ba92-15900ccc551e
Ieven, Margareta
c138048d-d838-4c8e-848d-a43e309f4cf0
Butler, Chris C.
cedab343-9e0c-420f-ba80-f2f824969687
Goossens, Herman
31f8e1ae-7da0-473c-bd49-f911c2187451
Little, Paul
1bf2d1f7-200c-47a5-ab16-fe5a8756a777
Verheij, Theo J.M.
817a26b8-7db9-4e79-b00e-c0457f19f236
Moore, Michael
1be81dad-7120-45f0-bbed-f3b0cc0cfe99

van Vugt, Saskia F., Broekhuizen, Berna D.L., Lammens, Christine, Zuithoff, Nicolaas P.A., de Jong, Pim A., Coenen, Samuel, Ieven, Margareta, Butler, Chris C., Goossens, Herman, Little, Paul, Verheij, Theo J.M. and Moore, Michael , GRACE Consortium (2013) Use of serum C reactive protein and procalcitonin concentrations in addition to symptoms and signs to predict pneumonia in patients presenting to primary care with acute cough: diagnostic study. British Medical Journal, 346, f2450. (doi:10.1136/bmj.f2450). (PMID:23633005)

Record type: Article

Abstract

OBJECTIVES: To quantify the diagnostic accuracy of selected inflammatory markers in addition to symptoms and signs for predicting pneumonia and to derive a diagnostic tool.

DESIGN: Diagnostic study performed between 2007 and 2010. Participants had their history taken, underwent physical examination and measurement of C reactive protein (CRP) and procalcitonin in venous blood on the day they first consulted, and underwent chest radiography within seven days.

SETTING: Primary care centres in 12 European countries.

PARTICIPANTS: Adults presenting with acute cough.

MAIN OUTCOME MEASURES: Pneumonia as determined by radiologists, who were blind to all other information when they judged chest radiographs.

RESULTS: Of 3106 eligible patients, 286 were excluded because of missing or inadequate chest radiographs, leaving 2820 patients (mean age 50, 40% men) of whom 140 (5%) had pneumonia. Re-assessment of a subset of 1675 chest radiographs showed agreement in 94% (? 0.45, 95% confidence interval 0.36 to 0.54). Six published "symptoms and signs models" varied in their discrimination (area under receiver operating characteristics curve (ROC) ranged from 0.55 (95% confidence interval 0.50 to 0.61) to 0.71 (0.66 to 0.76)). The optimal combination of clinical prediction items derived from our patients included absence of runny nose and presence of breathlessness, crackles and diminished breath sounds on auscultation, tachycardia, and fever, with an ROC area of 0.70 (0.65 to 0.75). Addition of CRP at the optimal cut off of >30 mg/L increased the ROC area to 0.77 (0.73 to 0.81) and improved the diagnostic classification (net reclassification improvement 28%). In the 1556 patients classified according to symptoms, signs, and CRP >30 mg/L as "low risk" (<2.5%) for pneumonia, the prevalence of pneumonia was 2%. In the 132 patients classified as "high risk" (>20%), the prevalence of pneumonia was 31%. The positive likelihood ratio of low, intermediate, and high risk for pneumonia was 0.4, 1.2, and 8.6 respectively. Measurement of procalcitonin added no relevant additional diagnostic information. A simplified diagnostic score based on symptoms, signs, and CRP >30 mg/L resulted in proportions of pneumonia of 0.7%, 3.8%, and 18.2% in the low, intermediate, and high risk group respectively.

CONCLUSIONS: A clinical rule based on symptoms and signs to predict pneumonia in patients presenting to primary care with acute cough performed best in patients with mild or severe clinical presentation. Addition of CRP concentration at the optimal cut off of >30 mg/L improved diagnostic information, but measurement of procalcitonin concentration did not add clinically relevant information in this group.

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Published date: 30 April 2013
Organisations: Primary Care & Population Sciences

Identifiers

Local EPrints ID: 352889
URI: https://eprints.soton.ac.uk/id/eprint/352889
ISSN: 0959-8138
PURE UUID: da709f80-65a8-438e-a0ef-00bc9ae6ba7b
ORCID for Michael Moore: ORCID iD orcid.org/0000-0002-5127-4509

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Date deposited: 21 May 2013 14:54
Last modified: 15 Oct 2019 00:44

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Contributors

Author: Saskia F. van Vugt
Author: Berna D.L. Broekhuizen
Author: Christine Lammens
Author: Nicolaas P.A. Zuithoff
Author: Pim A. de Jong
Author: Samuel Coenen
Author: Margareta Ieven
Author: Chris C. Butler
Author: Herman Goossens
Author: Paul Little
Author: Theo J.M. Verheij
Author: Michael Moore ORCID iD

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