Does C-reactive protein independently predict mortality in adult community-acquired bacteremia patients with known sepsis severity?

Inflammatory biomarkers to predict the prognosis of acute bacterial and viral infections

Mortality in acute infections is mostly associated with sepsis, defined as 'life-threatening organ dysfunction caused by a dysregulated host response to infection'. It remains challenging to identify the patients with increased mortality risk due to the high heterogeneity in the dysregulated host immune response and disease progression. Biomarkers reflecting different pathways involved in the inflammatory response might improve prediction of mortality risk (prognostic enrichment) among patients with acute infections by reducing heterogeneity of the host response, as well as suggest novel strategies for patient stratification and treatment (predictive enrichment) through precision medicine approaches. The predictive value of inflammatory biomarkers has been extensively investigated in bacterial infections and the recent COVID-19 pandemic caused an increased interest in inflammatory biomarkers in this viral infection. However, limited research investigated whether the prognostic potential of these biomarkers differs between bacterial and viral infections. In this narrative review, we provide an overview of the value of various inflammatory biomarkers for the prediction of mortality in bacterial and viral infections.

Impact of C-reactive protein and albumin levels on short, medium, and long term mortality in patients with diffuse large B-cell lymphoma

Objectives and study design: In this population-based study of 602 patients, we amended C-reactive protein (CRP) and plasma albumin (PA) levels around the diagnosis of diffuse large B-cell lymphoma (DLBCL) to the International Prognostic Index (IPI) and assessed 0-90, 91-365, and +365-day survival.Results: The CRP did not contribute to the IPI's prognostic or discriminatory ability, regardless of time period, particularly not in models with PA. In contrast, the PA was an important contributor, especially in the 0-90 day period, but also up to one year after the diagnosis. For day 0-90, the model with the IPI only had an Area Under the Receiver Operating Characteristics (AUROC) of 0.742, whereas the IPI with PA as a continuous variable rendered an AUROC of 0.841. Especially the lower PA quartile (18-32 g/L) contributed to the worse prognosis.Conclusions: The amendment of PA to the IPI may significantly improve the short-term prognostic and discriminative ability.Key messagesThe amendment of the plasma albumin (PA) level to the International Prognostic Index significantly improved the prediction of mortality up to one year after the diagnosis of diffuse large B-cell lymphoma.It was especially the lower quartile of the PA level (18-32 g/L) that contributed to the worse prognosis.

Plasma Neutrophil Gelatinase-Associated Lipocalin Is Useful for Predicting Mortality in Critically Ill Patients

Elevated neutrophil gelatinase-associated lipocalin (NGAL) occurs in a wide range of systemic diseases. This study examined the clinical utility of plasma NGAL to predict intensive care unit (ICU) and in-hospital mortality in critically ill patients. A total of 62 patients hospitalized in a mixed ICU were included; pNGAL, creatinine, and C-reactive protein (CRP) were assayed on four consecutive days (D1-D4) following ICU admission. APACHE II score (Acute Physiology and Chronic Health Evaluation) was calculated 24 h post-admission. ICU mortality reached 35% and in-hospital mortality was 39%. The median pNGAL at admission was 142.5 (65.6-298.3) ng/mL. pNGAL was significantly higher in non-survivors compared to survivors. The highest accuracy for ICU mortality prediction was achieved at the pNGAL cutoff of 93.91 ng/mL on D4 area under the curve (AUC) = 0.89; 95%CI 0.69-0.98 and for in-hospital mortality prediction was achieved at the pNGAL cutoff of 176.64 ng/mL on D3 (AUC = 0.86; 95%CI 0.69-0.96). The APACHE II score on ICU admission predicted ICU mortality with AUC = 0.89 (95%CI 0.79-0.96) and in-hospital mortality with AUC = 0.86 (95%CI 0.75-0.94). Although pNGAL on D1 poorly correlated with APACHE II (R = 0.3; p = 0.01), the combination of APACHE II and pNGAL on D1 predicted ICU mortality with AUC = 0.90 (95%CI 0.79-0.96) and in-hospital mortality with AUC = 0.95 (95%CI 0.78-0.99). Maximal CRP during study observation failed to predict ICU mortality (AUC = 0.62; 95%CI 0.49-0.74), but helped to predict in-hospital mortality (AUC = 0.67; 95%CI 0.54-0.79). Plasma NGAL with combination with the indices of critical illness is a useful biomarker for predicting mortality in heterogeneous population of ICU patients.

Independent Risk Factors for Sepsis-Associated Cardiac Arrest in Patients with Septic Shock

The clinical characteristics and laboratory values of patients with septic shock who experience in-hospital cardiac arrest (IHCA) have not been well studied. This study aimed to evaluate the prevalence of IHCA after admission into the emergency department and to identify the factors that increase the risk of IHCA in septic shock patients. This observational cohort study used a prospective registry of septic shock patients and was conducted at the emergency department of a university-affiliated hospital. The data of 887 adult (age ≥ 18 years) septic shock (defined using the Sepsis-3 criteria) patients who were treated with a protocol-driven resuscitation bundle therapy and were admitted to the intensive care unit between January 2010 and September 2018 were analyzed. The primary endpoint was the occurrence of sepsis-associated cardiac arrest. The patient mean age was 65 years, and 61.8% were men. Sepsis-associated cardiac arrest occurred in 25.3% of patients (n = 224). The 28-day survival rate after cardiac arrest was 6.7%. Multivariate logistic regression identified chronic pulmonary disease (odds ratio (OR) 2.06), hypertension (OR 0.48), unknown infection source (OR 1.82), a hepatobiliary infection source (OR 0.25), C-reactive protein (OR 1.03), and serum lactate level 6 h from shock (OR 1.34). Considering the high mortality rate of sepsis-associated cardiac arrest after cardiopulmonary resuscitation, appropriate monitoring is required in septic shock patients with major risk factors for IHCA.

C-reactive protein and albumin kinetics after antibiotic therapy in community-acquired bloodstream infection

OBJECTIVES

We assessed C-reactive protein (CRP) and plasma albumin (PA) kinetics to evaluate community-acquired bloodstream infection (CA-BSI) patients' 1-year outcomes.

METHODS

Population-based study, with CRP and PA measurements on day 1 (D1) and D4. Relative CRP variations in relation to D1 CRP value were evaluated (CRP-ratio). Patients were classified as fast response, slow response, non-response, and biphasic response.

RESULTS

A total of 935 patients were included. At D4, the CRP-ratio was lower in survivors on D365 in comparison with D4-D30 non-survivors and D30-D365 non-survivors (p<0.001). In comparison with fast response patients, non-response and biphasic response patients had 2.74 and 5.29 increased risk, respectively, of death in D4-D30 and 2.77 and 3.16 increased risk, respectively, of death in D31-D365. PA levels remained roughly unchanged from D1-D4, but lower D1 PA predicted higher short and long-term mortality (p<0.001). The discriminative performance of the CRP-ratio and D1 PA to identify patients with poor short and long-term mortality after adjustments was acceptable (AUROC=0.79).

CONCLUSIONS

Serial CRP measurements at D1 and D4 after CA-BSI is clinically useful to identify patients with poor outcome. Individual patterns of CRP-ratio response with PA at D1 further refine our ability of predicting short or long-term mortality.

C-reactive protein and albumin kinetics before community-acquired bloodstream infections - a Danish population-based cohort study

Early changes in biomarker levels probably occur before bloodstream infection (BSI) is diagnosed. However, this issue has not been fully addressed. We aimed at evaluating the kinetics of C-reactive protein (CRP) and plasma albumin (PA) in the 30 days before community-acquired (CA) BSI diagnosis. From a population-based BSI database we identified 658 patients with at least one measurement of CRP or PA from day −30 (D–30) through day −1 (D–1) before the day of CA-BSI (D0) and a measurement of the same biomarker at D0 or D1. Amongst these, 502 had both CRP and PA measurements which fitted these criteria. CRP and PA concentrations began to change inversely some days before CA-BSI diagnosis, CRP increasing by day −3.1 and PA decreasing by day −1.3. From D–30 to D–4, CRP kinetics (expressed as slopes – rate of concentration change per day) was −1.5 mg/l/day. From D–3 to D1, the CRP slope increased to 36.3 mg/l/day. For albumin, the slope between D–30 to D–2 was 0.1 g/l/day and changed to −1.8 g/l/day between D–1 and D1. We showed that biomarker levels begin to change some days before the CA-BSI diagnosis, CRP 3.1 days and PA 1.3 days before.

Peak C-reactive protein levels do not predict 30-day mortality for bacteremia: A retrospective cohort study

INTRODUCTION

Although peak C-reactive protein (CRP) levels are correlated with the prognosis of some diseases, there have been no reports regarding the association between peak CRP levels and mortality in patients with bacteremia. The present study aimed to determine the association between peak CRP levels and prognosis in patients with bacteremia.

METHODS

This retrospective cohort study was conducted in a single tertiary hospital and included patients with bacteremia admitted to the emergency department from November 2012 to March 2017. Cox regression analysis was performed to examine the association between peak CRP levels and 30-day mortality. We also performed propensity score adjustment using potential confounding factors.

RESULTS

One hundred fifty-nine patients were included in the study. Peak CRP levels were significantly higher in the β-hemolytic streptococci (P = 0.001) and Streptococcus pneumoniae (P = 0.003) groups. The C-statistic of the multivariate logistic regression model for the propensity score was 0.88. For 30-day mortality, peak CRP levels >20 mg/dL did not show significance in the Cox regression analysis (hazard ratio, 0.866; 95% confidence interval, 0.489-1.537; P = 0.62). Even after propensity score adjustment, no significance was noted (hazard ratio, 0.865; 95% confidence interval, 0.399-1.876; P = 0.71).

CONCLUSIONS

Peak CRP levels were not an independent predictor of mortality in patients with bacteremia in the emergency department. Clinicians should consider that patients with extremely high peak CRP levels do not necessarily have high mortality and vice versa.

Real-life data patterns of C-reactive protein and albumin level trajectories around bacteremia

AIM

To assess trajectory patterns of C-reactive protein (CRP) and plasma albumin (PA) levels around bacteremia.

PATIENTS & METHODS

Population-based study, 2418 community-acquired bacteremia patients, CRP and PA specimens from 30 days before through 30 days after bacteremia (day 0). A pattern was based on specimen occurring or not in days -30/-1, 0, 1/7 or 8/30. Mean daily CRP and PA levels on day -30/30 were computed for pattern subgroups.

RESULTS & CONCLUSION

Mean CRP rose on day -5 and reached its peak on day 1. Mean steady PA on day -30/0 declined abruptly on day 1, increasing slowly thereafter. Trajectories did not differ between subgroups. We conclude that longitudinal analysis results can be extrapolated to all community-acquired bacteremia patients.

Geriatric influenza death (GID) score: a new tool for predicting mortality in older people with influenza in the emergency department

Although influenza may cause death in the geriatric population, the best method for predicting mortality in this population is still unclear. We retrospectively recruited older people (≥65 yr) with influenza visiting the emergency department (ED) of a medical center between January 1, 2010, and December 31, 2015. We performed univariate and multivariate logistic regression to identify independent mortality predictors and then developed a prediction score. Four hundred nine older ED patients with a nearly equal sex ratio were recruited. Five independent mortality predictors were identified: severe coma (Glasgow Coma Scale score ≤8), past histories of cancer and coronary artery disease, elevated C-reactive protein levels (>10 mg/dl), and bandemia (>10% band cells). We divided the patients into three mortality risk and disposition groups: (1) low risk (1.1%; 95% confidence interval [CI], 0.5-3.0%); (2) moderate risk (16.7%; 95% CI, 9.3-28.0%); and (3) high risk (40%; 95% CI, 19.8-64.2%). The area under the receiver operating characteristic curve and the Hosmer-Lemeshow goodness of fit of the GID score were 0.86 and 0.578, respectively. The GID score is an efficient and simple tool for predicting mortality in older ED patients with influenza. Further studies are warranted to validate its use.

Hypoalbuminaemia as a marker of trans-capillary leakage in community-acquired bacteraemia patients

Community-acquired bacteraemia patients (n = 2472), Denmark, 2000-2008. Albumin, C-reactive protein (CRP) and haemoglobin (Hb) measured 2000-2010. We assessed daily mean levels of albumin, CRP and Hb from 30 days before to 30 days after bacteraemia and correlations between albumin vs. CRP and albumin vs. Hb. In linear regression models, we evaluated the contribution of CRP, Hb, chronic and acute variables to the albumin level variations. The mean albumin level (33.6 g/l) was steady before day 1, declined to 29.3 g/l on day 1 with little increase afterward. The mean CRP increased from day -5, peaked on day 1 and declined thereafter. The mean Hb level was fairly constant during days -30/30. Albumin was inversely (R range, - 0.18/-0.47, P < 10-4) correlated with the CRP level and positively (R = 0.17-0.46, P < 10-4) correlated with the HB level. In most models, CRP was the first variable that contributed to the albumin variations, 34-70% of the full model. The sudden decrease of albumin levels, without sudden fluctuations of CRP or Hb, indicated that hypoalbuminaemia was a marker of trans-capillary leakage.

Association between Hypoalbuminaemia and Mortality in Patients with Community-Acquired Bacteraemia Is Primarily Related to Acute Disorders

We sought to investigate whether hypoalbuminaemia was mainly caused by acute or chronic factors in patients with community-acquired bacteraemia. In this population-based study, we considered 1844 adult cases of community-acquired bacteraemia that occurred in Funen, Denmark between 2000 and 2008. We used a stepwise prognostic predisposition-insult-response-organ dysfunction (PIRO) logistic regression model by initially including age and comorbidity, then added bacterial species, and finally sepsis severity. The models were furthermore analysed using receiver operating characteristic (ROC) curves. Outcomes comprised mortality incidence on days 0-30 and 31-365 after the bacteraemia episode. Each step was performed with and without baseline albumin level measured on the date of bacteraemia. In 422 patients, their latest albumin measurement taken 8-30 days before the date of bacteraemia was also used in the analysis together with the baseline albumin level. For each decrease of 1g/L in plasma albumin level, the odds ratios (95% confidence intervals) of mortality in the period of 0-30 days after bacteraemia were 0.86 (0.84-0.88) in both predisposition (P) and predisposition-insult (PI) models and 0.87 (0.85-0.89) in the full PIRO-model. The AUC values were 0.78 and 0.66 for mortality in the period of 0-30 days in the model comprising only predisposition factors with and without albumin levels added as a factor, respectively. The AUC values in the full PIRO-model were 0.81 and 0.73 with and without consideration of albumin levels, respectively. A higher proportion of patients died within 30 days if there was a decrease in the albumin level between days 8 and 30 before bacteraemia and the actual bacteraemia date. A single plasma albumin measurement on the bacteraemia date was a better prognostic predictor of short-term mortality than the sepsis severity score.

Seasonal Variation of Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae Bacteremia According to Acquisition and Patient Characteristics: A Population-Based Study

OBJECTIVE Seasonal variation is a characteristic of many infectious diseases, but relatively little is known about determinants thereof. We studied the impact of place of acquisition and patient characteristics on seasonal variation of bacteremia caused by the 3 most common pathogens. DESIGN Seasonal variation analysis. METHODS In 3 Danish health regions (2.3 million total inhabitants), patients with bacteremia were identified from 2000 through 2011 using information from laboratory information systems. Analyses were confined to Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Additional data were obtained from the Danish National Hospital Registry for the construction of admission histories and calculation of the Charlson comorbidity index (CCI). Bacteremias were categorized as community acquired, healthcare associated (HCA), and hospital acquired. We defined multiple subgroups by combining the following characteristics: species, acquisition, age group, gender, CCI level, and location of infection. Assuming a sinusoidal model, seasonal variation was assessed by the peak-to-trough (PTT) ratio with a 95% confidence interval (CI). RESULTS In total, we included 16,006 E. coli, 6,924 S. aureus, and 4,884 S. pneumoniae bacteremia cases. For E. coli, the seasonal variation was highest for community-acquired cases (PTT ratio, 1.24; 95% CI, 1.17-1.32), was diminished for HCA (PTT ratio, 1.14; 95% CI, 1.04-1.25), and was missing for hospital-acquired cases. No seasonal variation was observed for S. aureus. S. pneumoniae showed high seasonal variation, which did not differ according to acquisition (overall PTT ratio, 3.42; 95% CI, 3.10-3.83). CONCLUSIONS Seasonal variation was mainly related to the species although the place of acquisition was important for E. coli. Infect Control Hosp Epidemiol 2016;37:946-953.

Low Completeness of Bacteraemia Registration in the Danish National Patient Registry

Bacteraemia is associated with significant morbidity and mortality and timely access to relia-ble information is essential for health care administrators. Therefore, we investigated the complete-ness of bacteraemia registration in the Danish National Patient Registry (DNPR) containing hospital discharge diagnoses and surgical procedures for all non-psychiatric patients. As gold standard we identified bacteraemia patients in three defined areas of Denmark (~2.3 million inhabitants) from 2000 through 2011 by use of blood culture data retrieved from electronic microbiology databases. Diagnoses coded according to the International Classification of Diseases, version 10, and surgical procedure codes were retrieved from the DNPR. The codes were categorized into seven groups, ranked a priori according to the likelihood of bacteraemia. Completeness was analysed by contin-gency tables, for all patients and subgroups. We identified 58,139 bacteraemic episodes in 48,450 patients; 37,740 episodes (64.9%) were covered by one or more discharge diagnoses within the sev-en diagnosis/surgery groups and 18,786 episodes (32.3%) had a code within the highest priority group. Completeness varied substantially according to speciality (from 17.9% for surgical to 36.4% for medical), place of acquisition (from 26.0% for nosocomial to 36.2% for community), and mi-croorganism (from 19.5% for anaerobic Gram-negative bacteria to 36.8% for haemolytic strepto-cocci). The completeness increased from 25.1% in 2000 to 35.1% in 2011. In conclusion, one third of the bacteraemic episodes did not have a relevant diagnosis in the Danish administrative registry recording all non-psychiatric contacts. This source of information should be used cautiously to iden-tify patients with bacteraemia.

No specific time window distinguishes between community-, healthcare-, and hospital-acquired bacteremia, but they are prognostically robust

OBJECTIVE

We examined whether specific time windows after hospital admission reflected a sharp transition between community and hospital acquisition of bacteremia. We further examined whether different time windows to distinguish between community acquisition, healthcare association (HCA), and hospital acquisition influenced the results of prognostic models.

DESIGN

Population-based cohort study.

SETTING

Hospitals in 3 areas of Denmark (2.3 million inhabitants) during 2000-2011.

METHODS

We computed graphs depicting proportions of males, absence of comorbidity, microorganisms, and 30-day mortality pertaining to bacteremia 0, 1, 2, …, 30, and 31 days and later after admission. Next, we assessed whether different admission (0-1, 0-2, 0-3, 0-7 days) and HCA (30, 90 days) time windows were associated with changes in odds ratio (OR) and area under the receiver operating characteristic (ROC) curve for 30-day mortality, adjusting for sex, age, comorbidity, and microorganisms.

RESULTS

For 56,606 bacteremic episodes, no sharp transitions were detected on a specific day after admission. Among the 8 combined time windows, ORs for 30-day mortality varied from 1.30 (95% confidence interval [CI], 1.23-1.37) to 1.99 (95% CI, 1.48-2.67) for HCA and from 1.36 (95% CI, 1.24-1.50) to 2.53 (95% CI, 2.01-3.20) for hospital acquisition compared with community acquisition. Area under the ROC curve changed marginally from 0.684 (95% CI, 0.679-0.689) to 0.700 (95% CI, 0.695-0.705).

CONCLUSIONS

No time transitions unanimously distinguished between community and hospital acquisition with regard to sex, comorbidity, or microorganisms, and no difference in 30-day mortality was seen for HCA patients in relation to a 30- or 90-day time window. ORs decreased consistently in the order of hospital acquisition, HCA, and community acquisition, regardless of time window combination, and differences in area under the ROC curve were immaterial.

Clinical characteristics and outcome of elderly patients with community-onset bacteremia

OBJECTIVES

To evaluate characteristics and prognostic factors of community-onset bloodstream infection (Co-BSI) in elderly patients (≥65 years).

METHODS

Analysis of a prospective series of Co-BSI at a tertiary hospital (2005-2011). Predictors of 30-day mortality were established by logistic regression analysis.

RESULTS

A total of 2605 episodes of Co-BSI were identified and empirical antibiotic treatment was inappropriate in 404 (15.5%). Thirty-day mortality was 11.4% and was independently associated with age (75-84 years OR 1.9, 1.37-2.67; ≥85 OR 2.85, 1.93-4.21), previous hospitalization (OR 1.45, 1.05-2.00), a fatal underlying disease (OR 2.81, 2.10-3.76), neutropenia (OR 2.62, 1.54-4.43), absence of fever (OR 1.99, 1.26-3.12), shock (OR 7.96, 5.83-10.89), inappropriate empirical treatment (OR 1.49, 1.03-2.16), isolation of Staphylococcus aureus (methicillin-resistant OR 2.83, 1.38-5.78; methicillin-susceptible OR 3.24, 1.98-5.32), enterococci (OR 2.02, 1.14-3.59) or Enterobacteriaceae resistant to third-generation cephalosporin (3GCR-E) (OR 1.96, 1.16-3.32) and having endovascular non-catheter (OR 4.64, 2.51-8.59), abdominal (OR 3.65, 2.12-6.27), skin/soft tissue (OR 3.48, 1.90-6.37), respiratory (OR 2.80, 1.75-4.50) or unknown (OR 1.83, 1.17-2.87) source.

CONCLUSIONS

Age is a prognostic factor and appropriateness of empirical treatment is the only modifiable variable. S. aureus, enterococci and 3GCR-E may be the microorganisms with major prognostic significance; hence efforts should be made to improve their management.

How do bacteraemic patients present to the emergency department and what is the diagnostic validity of the clinical parameters; temperature, C-reactive protein and systemic inflammatory response syndrome?

Objective

Although blood cultures are often ordered based on the presence of fever, it is a clinical challenge to identify patients eligible for blood cultures. Our aim was to evaluate the diagnostic value of temperature, C-reactive-protein (CRP), and Systemic Inflammatory Response Syndrome (SIRS) to identify bacteraemic patients in the Medical Emergency Department (MED).

Methods

A population-based cohort study including all adult patients at the MED at Odense University Hospital between August 1st 2009 - August 31st 2011.

Results

11,988 patients were admitted to the MED within the study period. Blood cultures were performed on 5,499 (45.9%) patients within 2 days of arrival, of which 418 (7.6%) patients were diagnosed with bacteraemia. This corresponded to 3.5% of all patients. 34.1% of the bacteraemic patients had a normal rectal temperature (36.0°–38.0°C) recorded at arrival, 32.6% had a CRP < 100 mg/L and 28.0% did not fulfil the SIRS criteria.

For a temperature cut-point of >38.0°C sensitivity was 0.64 (95% CI 0.59–0.69) and specificity was 0.81 (0.80–0.82) to identify bacteraemic patients.

Conclusion

One third of the acute medical bacteraemic patients had a normal temperature at arrival to the MED. A normal temperature combined with a CRP < 100 mg/L and no SIRS criteria, ruled out bacteraemia.

Characteristics of patients with community-acquired bacteremia who have low levels of C-reactive protein (≤20 mg/L)

OBJECTIVES

To characterize patients presenting with community-acquired bacteremia and a low C-reactive protein (CRP) plasma level at date of bacteremia.

METHODS

Population-based cohort study. Patient characteristics were compared for three CRP groups (≤20 mg/L, 21-100 mg/L and >100 mg/L) using chi-square test and oneway anova. The 30-day mortality rates were compared using logistic regression analyses.

RESULTS

Of the 2017 patients included, 193 (9.6%) had a CRP ≤20 mg/L. These patients were younger, more likely to be male, overrepresented in the intensive care unit and had more comorbidities. In blood cultures from the low CRP group hemolytic streptococci and coagulase-negative staphylococci were found relatively more common, whereas Streptococcus pneumoniae or Staphylococcus aureus were found relatively less common compared to the other CRP groups. The majority of patients with an initial low CRP mounted a CRP response the following days. The 30-day mortality rate was lower in the low CRP group (13.5%) than in the group with CRP >100 mg/L (20.6%).

CONCLUSIONS

A considerable proportion of patients with community-acquired bacteremia has a normal or low initial CRP level. The plasma CRP level should not be used to rule out serious infection or withhold antibiotic therapy.