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. 2021 Oct;49(5):935-943.
doi: 10.1007/s15010-021-01615-8. Epub 2021 May 22.

C-reactive protein and procalcitonin for antimicrobial stewardship in COVID-19

Isabell Pink #  1 , David Raupach #  1 , Jan Fuge  2 , Ralf-Peter Vonberg  3 , Marius M Hoeper  2 , Tobias Welte  2 , Jessica Rademacher  4
Affiliations

C-reactive protein and procalcitonin for antimicrobial stewardship in COVID-19

Isabell Pink et al. Infection. 2021 Oct.

Abstract

Purpose: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory coronavirus 2 (SARS-CoV-2) has spread around the world. Differentiation between pure viral COVID-19 pneumonia and secondary infection can be challenging. In patients with elevated C-reactive protein (CRP) on admission physicians often decide to prescribe antibiotic therapy. However, overuse of anti-infective therapy in the pandemic should be avoided to prevent increasing antimicrobial resistance. Procalcitonin (PCT) and CRP have proven useful in other lower respiratory tract infections and might help to differentiate between pure viral or secondary infection.

Methods: We performed a retrospective study of patients admitted with COVID-19 between 6th March and 30th October 2020. Patient background, clinical course, laboratory findings with focus on PCT and CRP levels and microbiology results were evaluated. Patients with and without secondary bacterial infection in relation to PCT and CRP were compared. Using receiver operating characteristic (ROC) analysis, the best discriminating cut-off value of PCT and CRP with the corresponding sensitivity and specificity was calculated.

Results: Out of 99 inpatients (52 ICU, 47 Non-ICU) with COVID-19, 32 (32%) presented with secondary bacterial infection during hospitalization. Patients with secondary bacterial infection had higher PCT (0.4 versus 0.1 ng/mL; p = 0.016) and CRP (131 versus 73 mg/L; p = 0.001) levels at admission and during the hospital stay (2.9 versus 0.1 ng/mL; p < 0.001 resp. 293 versus 94 mg/L; p < 0.001). The majority of patients on general ward had no secondary bacterial infection (93%). More than half of patients admitted to the ICU developed secondary bacterial infection (56%). ROC analysis of highest PCT resp. CRP and secondary infection yielded AUCs of 0.88 (p < 0.001) resp. 0.86 (p < 0.001) for the entire cohort. With a PCT cut-off value at 0.55 ng/mL, the sensitivity was 91% with a specificity of 81%; a CRP cut-off value at 172 mg/L yielded a sensitivity of 81% with a specificity of 76%.

Conclusion: PCT and CRP measurement on admission and during the course of the disease in patients with COVID-19 may be helpful in identifying secondary bacterial infections and guiding the use of antibiotic therapy.

Keywords: Antimicrobial stewardship; C-reactive protein; COVID-19; Procalcitonin; Secondary bacterial infections.

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Conflict of interest statement

IP received grants and/or advisory/lecture/clinical trial fees from Chiesi, outside the submitted work. MMH received grants and/or advisory/lecture/clinical trial fees from Acceleron, Actelion, Bayer, GSK, Janssen, MSD and Pfizer, outside the submitted work. TW received grants and/or advisory/lecture/clinical trial fees from DFG (German Research Council), BMBF (German Ministry of Research and Education), BMG (German Ministry of Health), EU, WHO (research grants), AstraZeneca, Basilea, Biotest, Bayer, Boehringer, Berlin Chemie, GSK, Infectopharm, MSD, Novartis, Pfizer, Roche (fees for lectures), AstraZeneca, Basilea, Biotest, Bayer, Boehringer, Gilead, GSK, Janssens, Novartis, Pfizer, Roche (advisory boards), outside the submitted work. JR received grants and/or advisory/lecture/clinical trial fees and/or non-financial support from AstraZeneca, Bayer, Brahms, Chiesi, Esanum, Grifols and Novartis, outside the submitted work. DR, JF, and RV declare that they have no conflict of interest.

Figures

Fig. 1
Fig. 1
Flow diagram of study cohort
Fig. 2
Fig. 2
ROC curve analysis for highest PCT level (a) and CRP level (b) as a marker for secondary infection in inpatients with COVID-19 pneumonia: Analysis revealed an area under the curve of 0.88 (p < 0.001) for PCT and 0.86 (p < 0.001) for CRP
See this image and copyright information in PMC

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