Kinetics of C-Reactive Protein and Procalcitonin in the Early Identification of ICU-Acquired Infections in Critically Ill COVID-19 Patients

Prognostic value of C-reactive protein levels in pulmonary infections: A systematic review and meta-analysis

BACKGROUND

C-reactive rotein (CRP) has been extensively studied as a biomarker that can predict mortality in patients with acute lung disease and our study aimed to elucidate the prognostic value of CRP levels for mortality in patients with various airway diseases, accounting for these differences and potential confounding factors accounts.

METHODS

An extensive literature search was conducted in several databases including PubMed, Embase, Web of Science, Scopus, and ProQuest to ensure the inclusion of up-to-date evidence from studies published between January 2019 and December 2024. Both fixed-effects and random-effects models were used to calculate pooled mean hazard ratios (HR) and odds ratios (OR) for mortality.

RESULTS

For mortality, the fixed effects model revealed a HR of 1.0065 (95% CI: 1.0054-1.0075, P < .0001), indicating a slightly increased risk of death associated with higher CRP levels. However, the random effects model, considering study heterogeneity, suggested an HR of 1.0488 (95% CI: 0.9978-1.1024, P = .0608), with significant heterogeneity (Q = 135.31, P < .0001). The OR analysis under the random effects model showed a more substantial increase in mortality risk with an OR of 1.2033 (95% CI: 1.0635-1.3614, P = .0033). Regarding ICU admissions and ventilation needs, substantial heterogeneity was also observed. The analysis did not find a statistically significant association between elevated CRP levels and ICU admission (OR = 1.1108, 95% CI: 0.9604-1.2847, P = .1568) or the necessity for ventilation (OR = 1.8981, 95% CI: 0.9651-3.7331, P = .0633), although both indicated trends towards increased risk.

CONCLUSION

CRP levels show a potential yet inconsistent association with mortality risk in patients with pulmonary infections. While elevated CRP levels suggest an increased risk of mortality, the results should be interpreted cautiously due to potential overestimation of the effect and the presence of publication bias.

Are C-reactive protein and procalcitonin safe and useful for antimicrobial stewardship purposes in patients with COVID-19? A scoping review

Objective

The primary objectives of this study were to assess the usefulness of C-reactive protein (CRP) and procalcitonin (PCT) in the diagnosis of bacterial co-infections in coronavirus disease 2019 (COVID-19) and if their incorporation in antimicrobial stewardship (AMS) programs is safe and useful, stratified by severity of disease as level of care, intensive care unit (ICU) or non-ICU. Our secondary objectives were to identify cut-off values for antibiotic decision-making and identify reported results from low- and middle-income countries (LMICs).

Design

A scoping review of published literature, adhering to the PRISMA statement for Systematic Reviews and Meta-analyses Extension for Scoping Reviews guidelines. The last search was performed in January 2024.

Results

Fifty-nine studies were included in this scoping review: 20 studies reporting predictive values and/or sensitivity/specificity results for PCT, 8 reporting clear objectives on AMS, and 3 studies from LMICs.

Conclusion

In the context of non-ICU hospitalized COVID-19 patients in high-income countries, a PCT value below 0.25 mg/L can be a useful tool to rule out bacterial co-infection. The wide range of reported negative predictive values suggests that PCT should be interpreted in the context of other clinical findings. Our results do not support the use of CRP in the same manner as PCT. There is a clear need for more studies in LMICs.

Distinct patterns of vital sign and inflammatory marker responses in adults with suspected bloodstream infection

OBJECTIVES

To identify patterns in inflammatory marker and vital sign responses in adult with suspected bloodstream infection (BSI) and define expected trends in normal recovery.

METHODS

We included patients ≥16 y from Oxford University Hospitals with a blood culture taken between 1-January-2016 and 28-June-2021. We used linear and latent class mixed models to estimate trajectories in C-reactive protein (CRP), white blood count, heart rate, respiratory rate and temperature and identify CRP response subgroups. Centile charts for expected CRP responses were constructed via the lambda-mu-sigma method.

RESULTS

In 88,348 suspected BSI episodes; 6908 (7.8%) were culture-positive with a probable pathogen, 4309 (4.9%) contained potential contaminants, and 77,131(87.3%) were culture-negative. CRP levels generally peaked 1-2 days after blood culture collection, with varying responses for different pathogens and infection sources (p < 0.0001). We identified five CRP trajectory subgroups: peak on day 1 (36,091; 46.3%) or 2 (4529; 5.8%), slow recovery (10,666; 13.7%), peak on day 6 (743; 1.0%), and low response (25,928; 33.3%). Centile reference charts tracking normal responses were constructed from those peaking on day 1/2.

CONCLUSIONS

CRP and other infection response markers rise and recover differently depending on clinical syndrome and pathogen involved. However, centile reference charts, that account for these differences, can be used to track if patients are recovering line as expected and to help personalise infection.