Comparative Impact of C-Reactive Protein Testing in Hospitalized Patients with Acute Respiratory Tract Infection: A Retrospective Cohort Study
Evidence-based data on the usefulness of C-reactive protein (CRP) monitoring in patient outcomes are lacking. CRP testing in patients with acute respiratory tract infections (ARTIs) showed wide variability between internal medicine wards in our hospital network. In this study we aimed to investigate whether repetitive CRP tests might influence the switch of antibiotic therapy from intravenous (IV) to oral (PO) route and whether CRP measurements affect the combined outcome of readmission and in-hospital mortality.
This was a retrospective cohort study conducted in two internal medicine wards selected in a network of five teaching hospitals on the basis of their CRP prescription frequency. Clinical and laboratory data of 296 patients with ARTIs and admitted from 1 January to 31 December 2016 were analyzed.
The mean ± SD of CRP tests/patient and the in-hospital length of antibiotic therapy (days) in the low-CRP (L-CRP) vs the high-CRP (H-CRP) wards were 1.14 ± 0.62 vs 3.43 ± 1.54 (p < 0.001) and 7.1 ± 2.6 vs 7.5 ± 3.2 (p = 0.298), respectively. The probability of antibiotic switching was higher in the L-CRP ward (HR 2.90, 95% CI 1.69–4.95, p < 0.001) correlating with the lower number of CRP determinations (HR 1.20, 95% CI 1.01–1.41, p = 0.034). In-hospital readmissions and mortality rates did not significantly differ between the two wards (L-CRP 17.1% vs H-CRP 10.0%, p = 0.133). The number of CRP determinations affected the combined outcome (OR 1.38, 95% CI 1.01–1.90, p = 0.043).
Repetitive CRP testing in ARTIs offers no added value to either antibiotic switch or patient outcomes in hospitalized patients in internal medicine wards.
KeywordsAntibiotic therapy C-reactive protein Choosing Wisely Infectious disease Primary and hospital care Respiratory tract infections
No funding or sponsorship was received for this study or publication of this article. The Rapid Service Fee was funded by the authors. This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship for this article, take responsibility for the integrity of the work as a whole, and have given their approval for this version to be published.
Olivier Giannini and Rosaria Del Giorno contributed equally to this work.
Olivier Giannini, Rosaria Del Giorno, Anna Zasa and Luca Gabutti declare that they have no conflicts of interest.
Compliance with Ethics Guidelines
The study was conducted in accordance with the Declaration of Helsinki. The study was exempt from institutional review board approval by the Swiss Ethics Committee because it involved anonymous secondary data only. Informed consent was not obtained because the data were from de-identified and previously collected administrative data.
The dataset analyzed during the current study is available from the corresponding author on reasonable request.
- 1.American Society of Clinical Pathology Recommendations. Choosing Wisely Campaign. http://www.choosingwisely.org. Updated February 2, 2015.
- 4.Perrig M, Beck T, Wertli M, Donzé J, Rodondi N, Aujesky D. Rationale Labortests in der stationären Allgemeinen Inneren Medizin. Schweiz Ärtzteztg. 2018;99:1266–9.Google Scholar
- 5.American Board of Internal Medicine (ABIM) Foundation. Choosing Wisely. About the Campaign, 2015. http://www.choosingwisely.org/wpcontent/uploads/2015/04/About-Choosing-Wisely.pdf. Updated November 25, 2015.
- 7.Hopstaken RM, Muris JW, Knottnerus JA, Kester AD, Rinkensand PE, Dinant GJ. Contributions of symptoms, signs, erythrocyte sedimentation rate, and C-reactive protein to a diagnosis of pneumonia in acute lower respiratory tract infection. Br J Gen Pract. 2003;53(490):358–64.PubMedPubMedCentralGoogle Scholar