RT Journal Article
SR Electronic
T1 The added value of C-reactive protein measurement in diagnosing pneumonia in primary care: a meta-analysis of individual patient data
JF Canadian Medical Association Journal
JO CMAJ
FD Canadian Medical Association
SP E56
OP E63
DO 10.1503/cmaj.151163
VO 189
IS 2
A1 Margaretha C. Minnaard
A1 Joris A.H. de Groot
A1 Rogier M. Hopstaken
A1 Alwin Schierenberg
A1 Niek J. de Wit
A1 Johannes B. Reitsma
A1 Berna D.L. Broekhuizen
A1 Saskia F. van Vugt
A1 Arie Knuistingh Neven
A1 Aleida W. Graffelman
A1 Hasse Melbye
A1 Timothy H. Rainer
A1 Johann Steurer
A1 Anette Holm
A1 Ralph Gonzales
A1 Geert-Jan Dinant
A1 Alma C. van de Pol
A1 Theo J.M. Verheij
YR 2017
UL http://www.cmaj.ca/content/189/2/E56.abstract
AB BACKGROUND: C-reactive protein (CRP) is increasingly being included in the diagnostic work-up for community-acquired pneumonia in primary care. Its added diagnostic value beyond signs and symptoms, however, remains unclear. We conducted a meta-analysis of individual patient data to quantify the added value of CRP measurement.METHODS: We included studies of the diagnostic accuracy of CRP in adult outpatients with suspected lower respiratory tract infection. We contacted authors of eligible studies for inclusion of data and for additional data as needed. The value of adding CRP measurement to a basic signs-and-symptoms prediction model was assessed. Outcome measures were improvement in discrimination between patients with and without pneumonia in primary care and improvement in risk classification, both within the individual studies and across studies.RESULTS: Authors of 8 eligible studies (n = 5308) provided their data sets. In all of the data sets, discrimination between patients with and without pneumonia improved after CRP measurement was added to the prediction model (extended model), with a mean improvement in the area under the curve of 0.075 (range 0.02–0.18). In a hypothetical cohort of 1000 patients, the proportion of patients without pneumonia correctly classified at low risk increased from 28% to 36% in the extended model, and the proportion with pneumonia correctly classified at high risk increased from 63% to 70%. The number of patients with pneumonia classified at low risk did not change (n = 4). Overall, the proportion of patients assigned to the intermediate-risk category decreased from 56% to 51%.INTERPRETATION: Adding CRP measurement to the diagnostic work-up for suspected pneumonia in primary care improved the discrimination and risk classification of patients. However, it still left a substantial group of patients classified at intermediate risk, in which clinical decision-making remains challenging.