Inflammatory biomarkers for the diagnosis, monitoring and follow-up of community-acquired pneumonia: clinical evidence and perspectives

Serum Krebs von den Lungen-6 is associated with in-Hospital mortality of patients with severe Community-Acquired Pneumonia: A retrospective cohort study

BACKGROUND

Currently, no ideal biomarker can accurately stratify the risk of patients with severe community-acquired pneumonia (SCAP). This study aimed to evaluate the role of serum Krebs von den Lungen-6 (sKL-6) in predicting in-hospital mortality in adults with SCAP.

METHODS

In this retrospective cohort study, 249 severe pneumonia adult patients were recruited between 6 May 2021 to 30 April 2023 in Xiangya Hospital of Central South University. The sKL-6 level within 48 h of admission was measured, and the primary outcome assessed was in-hospital mortality. Multivariable logistic regression analysis was performed to calculate adjusted odds ratios (OR) with 95% confidence intervals (CI). Survival curves were plotted and subgroup analyses were conducted, stratified by relevant covariates.

RESULTS

A total of 249 patients were included in the study,with 124 patients having normal sKL-6 levels, and 125 patients having abnormal sKL-6 levels. The overall in-hospital mortality rate was 28.9% (72 out of 249 patients). Univariate and multivariate logistic regression analysis revealed that the patients with abnormal sKL-6 levels had a higher risk of in-hospital mortality compared to those with normal sKL-6 levels, both in the total SCAP patient population (OR: 5.38, 95%CI: 2.41-12.01, P < 0.001) and the non-COVID-19 SCAP patients subgroup (OR: 8.12, 95%CI: 3.16-20.84, P < 0.001). Subgroup and interaction analyses confirmed the stability of the relationship between sKL-6 levels and in-hospital mortality(P for interaction > 0.05). Kaplan-Meier survival curves showed that patients with abnormal sKL-6 levels had a higher in-hospital mortality rate than those with normal sKL-6 levels (P < 0.05). However, the results of restricted cubic spline plots(RCS) analysis demonstrated a nonlinear association between sKL-6 levels (as a continuous variable) and in-hospital mortality in patients with SCAP. Similar results were observed in non-COVID-19 SCAP patients. Furthermore, the receiver operating characteristic curve (ROC) analysis revealed that sKL-6 had superior predictive performance compared to existing biomarkers (e.g., APACHE-II, SOFA, BUN/Cr, PCT, and D-dimer) for in-hospital mortality in non-COVID-19 SCAP patients.

CONCLUSION

sKL-6 is a practical and useful biomarker for predicting in-hospital mortality in patients with SCAP.

Comparison of a novel automated DiaSys procalcitonin immunoassay with four different BRAHMS-partnered immunoassays

Objectives

Procalcitonin (PCT) is an important biomarker of sepsis and respiratory infections. Various automated immunoassays for measuring PCT in patient plasma are available in medical laboratories. However, due to a lack of international reference material for PCT, the assays are not always comparable.

Design and methods

In this study, we compared a new turbidimetric immunoassay from DiaSys, measured on the Abbott Architect c16000 and Alinity c, with four BRAHMS-associated chemiluminescence immunoassays (Abbott Architect i2000SR, Alinity i, Roche Cobas e411 and DiaSorin Liaison XL) using 120 random patient plasma samples from the clinical laboratory routine at the University Medical Center Goettingen.

Results

The DiaSys assay showed clear differences as compared to the BRAHMS-associated assays when measured on Architect c: i.e. 58% positive mean bias vs. Architect i, 67% vs. Cobas and 23% vs. Liaison. As a result, additional 19% our patients would have a suspected bacterial infection, when using PCT values from the DiaSys assay and commonly accepted decision limits. A crosscheck of the DiaSys calibrator on the BRAHMS-associated systems showed a low recovery of the calibrator material (approx. 50%).

Conclusions

Overall, this study shows significant differences between the DiaSys and BRAHMS-associated assays. This could be attributed to a potential DiaSys calibrator problem. This highlights the need for an international reference material for harmonization of the PCT assays.

Association of Red Blood Cell Distribution Width Levels with Connective Tissue Disease-Associated Interstitial Lung Disease (CTD-ILD)

Objective

The aim of this study was to evaluate the diagnostic and prognostic value of red blood cell distribution width (RDW) in patients with connective tissue disease-associated interstitial lung disease (CTD-ILD).

Methods

We retrospectively reviewed 213 CTD-ILD patients and 97 CTD patients without ILD from February 2017 to February 2020. Hospital and office records were used as data sources. CTD-ILD patients were followed up.

Results

Patients with CTD-ILD had significantly higher RDW than those with CTD without ILD (p < 0.001). The area under the receiver operating characteristic curve (AUROC) of RDW for discriminating CTD-ILD from CTD without ILD was 0.64 (95% CI: 0.57-0.70, p < 0.001). The cutoff value of RDW for discriminating CTD-ILD from CTD without ILD was 13.95% with their corresponding specificity (55.9%) and sensitivity (70.1%). Correlation analyses showed that the increased RDW was significantly correlated with decreased DLCO%predicted (r = −0.211, p = 0.002). Cox multiple regression analysis indicated that RDW (HR = 1.495, p < 0.001) was an independent factor in the survival of CTD-ILD. The best cutoff value of RDW to predict the survival of patients with CTD-ILD was 14.05% (AUC = 0.78, 95% CI: 0.72-0.84, p < 0.001). The log-rank test showed a significant difference in survival between the two groups (RDW > 14.05% and RDW < 14.05%).

Conclusion

RDW was higher in CTD-ILD patients and had a negative correlation with DLCO%predicted. RDW may be an important serum biomarker for severity and prognosis of patients with CTD-ILD.

Two-center comparison of 10 fully-automated commercial procalcitonin (PCT) immunoassays

Background This two-center study was designed to verify comparability of procalcitonin (PCT) values among 10 different commercial immunoassays. Methods A total number of 176 routine lithium-heparin plasma samples were divided in identical aliquots and simultaneously analyzed with 10 different PCT immunoassays, including Kryptor BRAHMS PCT sensitive, Abbott Architect BRAHMS PCT, Beckman Coulter Access PCT (on Access and DXI), BioMérieux Vidas BRAHMS PCT, Diasorin Liaison BRAHMS PCT, Fujirebio Lumipulse G BRAHMS PCT, Roche BRAHMS PCT (on Cobas E801), Diazyme PCT (on Roche Cobas C702) and SNIBE Maglumi PCT. Results Highly significant correlation was always found across multiple comparisons, with correlation coefficients comprised between 0.918 and 0.997 (all p < 0.001). Bland and Altman plots analysis revealed highly variable bias among immunoassays, ranging between ±0.2% and ±38.6%. Diazyme PCT on Roche Cobas C702 and SNIBE Maglumi PCT displayed the larger overestimation, whilst PCT values were underestimated by Cobas BRAHAMS PCT. The agreement was always >80% (all p < 0.001), but varied largely across multiple comparisons, ranging between 90%-99% at 0.1 μg/L, 81%-99% at 0.25 μg/L, 83%-100% at 0.5 μg/L, 94%-100% at 2.0 μg/L and 90%-99% at 10 μg/L, respectively. The larger disagreement was observed comparing Diazyme PCT and Maglumi PCT with the other methods. Conclusions Although we found acceptable correlation among 10 commercial PCT immunoassays, the limited agreement at clinical decision thresholds remains a major issue, especially at lower end of PCT concentration, thus potentially contributing to jeopardize the clinical value of this biomarker.

Development of a novel chemiluminescence immunoassay for the detection of procalcitonin

OBJECTIVE

To evaluate the analytical performance of our previously developed chemiluminescence immunoassay (CLIA) kit for the detection of procalcitonin (PCT) and compare with the results obtained using the Vidas B.R.A.H.M.S. PCT™ test (PCT-V).

DESIGN AND METHODS

Our laboratory previously designed a novel CLIA kit and supporting instrument (AE-180) for the detection of PCT. We analyzed the clinical performance of this system, including the imprecision, limit of detection, and linearity of analyses of 305 serum specimens. The results were compared with measurements of the same serum samples obtained with PCT-V.

RESULTS

The limit of detection and blank of our kit were 0.0075 and 0.0039 ng/mL, respectively. The intra- and inter-assay coefficient of variation of the kit were both between 0.8% and 3.9%. The equation of linearity was found to be y = 1.03× + 0.06 (r = 0.99) for concentrations in the range of 0.01-110 ng/mL. The correlation coefficient with the results of PCT-V was 0.995, and the equation obtained for Passing and Bablok regression analysis was 1.061 for our CLIA PCT kit and - 0.003 for PCT-V. Our kit slightly overestimated the concentration according to comparison with PCT-V results.

CONCLUSION

The kit that was previously developed in our laboratory for the measurement of serum PCT concentration using CLIA technology shows excellent performance, just that the functional sensitivity is not as good as the PCT-V; therefore, we suggest that this kit is suitable for clinical use.

Serum metabolite profiles as potential biochemical markers in young adults with community-acquired pneumonia cured by moxifloxacin therapy

Despite the utilization of various biochemical markers and probability calculation algorithms based on clinical studies of community-acquired pneumonia (CAP), more specific and practical biochemical markers remain to be found for improved diagnosis and prognosis. In this study, we aimed to detect the alteration of metabolite profiles, explore the correlation between serum metabolites and inflammatory markers, and seek potential biomarkers for young adults with CAP. 13 Eligible young mild CAP patients between the ages of 18 and 30 years old with CURB65 = 0 admitted to the respiratory medical department were enrolled, along with 36 healthy participants as control. Untargeted metabolomics profiling was performed and metabolites including alcohols, amino acids, carbohydrates, fatty acids, etc. were detected. A total of 227 serum metabolites were detected. L-Alanine, 2-Hydroxybutyric acid, Methylcysteine, L-Phenylalanine, Aminoadipic acid, L-Tryptophan, Rhamnose, Palmitoleic acid, Decanoylcarnitine, 2-Hydroxy-3-methylbutyric acid and Oxoglutaric acid were found to be significantly altered, which were enriched mainly in propanoate and tryptophan metabolism, as well as antibiotic-associated pathways. Aminoadipic acid was found to be significantly correlated with CRP levels and 2-Hydroxy-3-methylbutyric acid and Palmitoleic acid with PCT levels. The top 3 metabolites of diagnostic values are 2-Hydroxybutyric acid(AUC = 0.90), Methylcysteine(AUC = 0.85), and L-Alanine(AUC = 0.84). The AUC for CRP and PCT are 0.93 and 0.91 respectively. Altered metabolites were correlated with inflammation severity and were of great diagnostic value for CAP.

Analytical Evaluation of the New Beckman Coulter Access Procalcitonin (PCT) Chemiluminescent Immunoassay

This study was designed to evaluate the analytical performance of the recently commercialized Beckman Coulter Access procalcitonin (PCT) chemiluminescent test on the Access immunoassay system. The analytical assessment encompassed the estimation of limit of blank (LoB), limit of detection (LoD), functional sensitivity (i.e., PCT value with ≤10% imprecision), linearity, imprecision and comparability of values with BRAHMS PCT-sensitive Kryptor. LoB, LoD and functional sensitivity were 0.002 μg/L, 0.003 μg/L and 0.003 μg/L, respectively. Intra-assay, inter-assay and total imprecision for plasma pools with low, medium and high PCT values were 1.8–2.1%, 2.4–3.7% and 3.1–4.3%, respectively. The assay exhibited excellent linearity between 0.02 and 84.0 μg/L. Excellent correlation (r = 0.999; p < 0.001) and negligible bias (3.2%) were found by comparing values obtained in paired plasma samples with BRAHMS PCT-sensitive Kryptor. Diagnostic agreement at 0.5, 2.0 and 10 μg/L PCT values ranged between 98%-100%. The results of this study confirm that Access PCT displays excellent analytical performance and high comparability with BRAHMS PCT-sensitive Kryptor.

Study on the Red Blood Cell Distribution Width in Connective Tissue Disease Associated with Interstitial Lung Disease

Background

Connective tissue disease (CTD) associated with interstitial lung disease (ILD) affects the lungs and can lead to considerable morbidity and shortened survival. Red blood cell distribution width (RDW) is a readily available parameter that is routinely reported with complete blood cell count (CBC) This study aimed to investigate the predictive value of RDW in CTD-ILD.

Methods

A retrospective analysis was performed on 180 patients with CTD-ILD and 202 patients with CTD but without ILD between April 2016 and December 2018. Baseline demographics, laboratory results, imaging examinations, and results of ultrasound scans were analysed.

Results

In comparison with patients without ILD, patients with CTD-ILD displayed a larger RDW (14.65 ± 2.08 vs. 14.17 ± 1.63, P=0.002), and RDW shared positive relationships with pulmonary artery systolic pressure (r = 0.349; P=0.002), and RDW shared positive relationships with pulmonary artery systolic pressure (r = 0.349; P=0.002), and RDW shared positive relationships with pulmonary artery systolic pressure (r = 0.349; P=0.002), and RDW shared positive relationships with pulmonary artery systolic pressure (P=0.002), and RDW shared positive relationships with pulmonary artery systolic pressure (P=0.002), and RDW shared positive relationships with pulmonary artery systolic pressure (P=0.002), and RDW shared positive relationships with pulmonary artery systolic pressure (

Conclusions

RDW was significantly increased in patients with CTD-ILD under various CTD backgrounds and may be a promising biomarker that may help physicians predict CTD-ILD risk.

PedCAPNETZ - prospective observational study on community acquired pneumonia in children and adolescents

Background

Pediatric community acquired pneumonia (pedCAP) is one of the leading causes for childhood morbidity accounting for up to 20% of pediatric hospital admissions in high income countries. In spite of its high morbidity, updated epidemiological and pathogen data after introduction of preventive vaccination and novel pathogen screening strategies are limited. Moreover, there is a need for validated recommendations on diagnostic and treatment regimens in pedCAP. Through collection of patient data and analysis of pathogen and host factors in a large sample of unselected pedCAP patients in Germany, we aim to address and substantially improve this situation.

Methods

pedCAPNETZ is an observational, multi-center study on pedCAP. Thus far, nine study centers in hospitals, outpatient clinics and practices have been initiated and more than 400 patients with radiologically confirmed pneumonia have been enrolled, aiming at a total of 1000 study participants. Employing an online data base, information on disease course, treatment as well as demographical and socioeconomical data is recorded. Patients are followed up until day 90 after enrollment; Comprehensive biosample collection and a central pedCAPNETZ biobank allow for in-depth analyses of pathogen and host factors. Standardized workflows to assure sample logistics and data management in more than fifteen future study centers have been established.

Discussion

Through comprehensive epidemiological, clinical and biological analyses, pedCAPNETZ fills an important gap in pediatric and infection research. To secure dissemination of the registry, we will raise clinical and scientific awareness at all levels. We aim at participating in decision making processes for guidelines and prevention strategies. Ultimately, we hope the results of the pedCAPNETZ registry will help to improve care and quality of life in pedCAP patients in the future.

Procalcitonin in inflammatory bowel disease: Drawbacks and opportunities

The measurement of procalcitonin has recently become a mainstay for the diagnosis and therapeutic management of severe bacterial infections, especially those sustained by Gram-negative bacteria. Therefore, the aim of this article is to provide a narrative overview on the potential role of procalcitonin measurement in patients with inflammatory bowel disease (IBD). According to the available scientific literature, the clinical significance of procalcitonin for diagnosing IBD or monitoring disease activity remains elusive, and its association with disease severity is confined to a limited number of case-control studies, with low sample size. Nevertheless, literature data also suggests that a supranormal procalcitonin serum concentration (i.e., > 0.5 ng/mL) may reflect the presence of a number of infective complications in IBD, especially bacterial enterocolitis, bacterial gastroenteritis, intraabdominal abscess, postsurgical infection and sepsis. Rather than for diagnosing or assessing disease activity, the measurement of this biomarker may hence retain practical clinical significance for early prediction, timely diagnosis and therapeutic monitoring of many IBD-associated infections and complications.

Circulating level of high mobility group box‑1 predicts the severity of community‑acquired pneumonia: Regulation of inflammatory responses via the c‑Jun N‑terminal signaling pathway in macrophages

High mobility group box‑1 (HMGB‑1) has been reported to serve significant roles in various inflammatory diseases. However, the correlation between the circulating level of HMGB‑1 and severity of community‑acquired pneumonia (CAP) remains unclear. The present study investigated differential alterations in plasma HMGB‑1 levels of patients with CAP prior to and following antibiotic treatment, and further analyzed the association between CAP severity and HMGB‑1 levels. Furthermore, lipopolysaccharide (LPS)‑induced HMGB‑1 expression in RAW264.7 macrophages and the relevant signaling pathways were examined. Plasma HMGB‑1 levels of 90 patients with CAP and 52 healthy controls were measured using a commercial ELISA. The levels of plasma HMGB‑1 were significantly elevated in CAP patients compared with the controls, and antibiotic treatment was effective in reducing HMGB‑1 levels. Plasma HMGB‑1 correlated with the pneumonia severity index score (r=0.566, P<0.001). Furthermore, LPS‑stimulation significantly upregulated HMGB‑1 secretion via the c‑Jun N‑terminal kinase (JNK) signaling pathway in RAW264.7 macrophages, whereas pretreatment with the JNK inhibitor SP600125 markedly downregulated LPS‑induced HMGB‑1 levels. In conclusion, plasma HMGB‑1 levels may serve a role in the diagnosis and clinical assessment of CAP severity. These findings may provide information on novel targets for the treatment of CAP.

Biomarkers in Pediatric Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) is an infectious disease caused by bacteria, viruses, or a combination of these infectious agents. The severity of the clinical manifestations of CAP varies significantly. Consequently, both the differentiation of viral from bacterial CAP cases and the accurate assessment and prediction of disease severity are critical for effectively managing individuals with CAP. To solve questionable cases, several biomarkers indicating the etiology and severity of CAP have been studied. Unfortunately, only a few studies have examined the roles of these biomarkers in pediatric practice. The main aim of this paper is to detail current knowledge regarding the use of biomarkers to diagnose and treat CAP in children, analyzing the most recently published relevant studies. Despite several attempts, the etiologic diagnosis of pediatric CAP and the estimation of the potential outcome remain unsolved problems in most cases. Among traditional biomarkers, procalcitonin (PCT) appears to be the most effective for both selecting bacterial cases and evaluating the severity. However, a precise cut-off separating bacterial from viral and mild from severe cases has not been defined. The three-host protein assay based on C-reactive protein (CRP), tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), plasma interferon-γ protein-10 (IP-10), and micro-array-based whole genome expression arrays might offer more advantages in comparison with former biomarkers. However, further studies are needed before the routine use of those presently in development can be recommended.

C-reactive protein (CRP) measurement in geriatric patients hospitalized for acute infection

The physiology of inflammatory response is modified by the aging process and is substantially affected by multimorbidity and disability. Infection is the most frequent cause of acute inflammation in both adult and older subjects. C-reactive protein (CRP) is the most used biomarker of inflammation, and a substantial amount of literature has demonstrated its importance and clinical usefulness in adult subjects. However, the clinical significance of serum CRP determination has not been completely clarified in older subjects with acute infection, especially in the light of the age-related rearrangements in immunity and cytokine production. Thus, in the present review, we focus on the existing knowledge about serum CRP level interpretation in geriatric patients hospitalized with acute infection. Our aims were to determine the significance of CRP measurement at hospital admission for establishing a diagnosis of infection and/or a prognosis and to evaluate whether it is indicated to repeat hs-CRP measurements during hospital stay for monitoring disease course and, possibly, guiding the discharge timing. We concluded that CRP dosage at hospital admission is helpful to detect acute infection, and particularly sepsis, in geriatric patients, and that CRP elevation may provide valuable short-term prognostic information. At the current state of art, serial CRP measurements are instead not indicated to monitor disease course and plan hospital discharge in this setting.

Economic evaluation of procalcitonin-guided antibiotic therapy in acute respiratory infections: a Chinese hospital system perspective

Background:

Cost-impact models have indicated that in the USA, the use of antibiotic stewardship protocols based on procalcitonin (PCT) levels for patients with suspected acute respiratory tract infection results in cost savings. Our objective was to assess the cost impact of adopting PCT testing among patients with acute respiratory infections (ARI) from the perspective of a typical hospital system in urban China.

Methods:

To conduct an economic evaluation of PCT testing versus usual care we built a cost-impact model based on a previously published patient-level meta-analysis data of randomized trials including Chinese sites. The data were adapted to the China setting by applying the results to mean lengths of stay, costs, and practice patterns typically found in China. We estimated the annual ARI visit rate for the typical hospital system (assumed to be 1650 beds) and ARI diagnosis.

Results:

In the inpatient setting, the costs of PCT-guided care compared to usual care for a cohort of 16,405 confirmed ARI patients was almost 1.1 million Chinese yuan (CNY), compared to almost 1.8 million CNY for usual care, resulting in net savings of 721,563 CNY to a typical urban Chinese hospital system for 2015. In the ICU and outpatient settings, savings were 250,699 CNY and 2.4 million CNY, respectively. The overall annual net savings of PCT-guided care was nearly 3.4 million CNY.

Conclusions:

Substantial savings are associated with PCT protocols of ARI across common China hospital treatment settings mainly by direct reduction in unnecessary antibiotic utilization.

How and when to use common biomarkers in community-acquired pneumonia

Community-acquired pneumonia (CAP) is a leading cause of death in both the developed and developing world. The very young and elderly are especially vulnerable. Even with appropriate early antibiotics we still have not improved the outcomes in these patients since the 1950s, with 30-day case fatality rates of between 10-12%. Interventions to improve outcomes include immunomodulatory agents such as macrolides and corticosteroids. Treating doctors identify CAP patients who are likely to have poor outcomes by using severity scores such as the pneumonia severity index and CURB-65, which allows these patients to be placed in ICU settings from the start of the admission. Another novel way to identify these patients is with the use of biomarkers. This review illustrates how various biomarkers have been shown to predict mortality, complications and response to treatment in CAP patients. The evidence using either procalcitonin or C-reactive protein to demonstrate response to treatment and hence that the antibiotics chosen are appropriate can play an important role in antibiotic stewardship.

Analytical evaluation of the novel Lumipulse G BRAHMS procalcitonin immunoassay

Objectives

This study was designed to evaluate the analytical performance of the novel Lumipulse G1200 BRAHMS procalcitonin (PCT) immunoassay.

Design and methods

This analytical evaluation encompassed the calculation of the limit of blank (LOB), limit of detection (LOD), functional sensitivity, intra- and inter-assay imprecision, confirmation of linearity and a comparison with the Vidas BRAHMS PCT assay.

Results

The LOB, LOD and functional sensitivity were 0.0010 ng/mL, 0.0016 ng/mL and 0.008 ng/mL, respectively. The total analytical imprecision was found to be 2.1% and the linearity was excellent (r=1.00) in the range of concentrations between 0.006–75.5 ng/mL. The correlation coefficient with Vidas BRAHMS PCT was 0.995 and the equation of the Passing and Bablok regression analysis was [Lumipulse G BRAHMS PCT]=0.76×[Vidas BRAHMS PCT]+0.04. The mean overall bias of Lumipulse G BRAHMS PCT versus Vidas BRAHMS PCT was −3.03 ng/mL (95% confidence interval [CI]: −4.32 to −1.74 ng/mL), whereas the mean bias in samples with PCT concentration between 0–10 ng/mL was −0.49 ng/mL (95% CI: −0.77 to −0.24 ng/mL). The diagnostic agreement was 100% at 0.5 ng/mL, 97% at 2.0 ng/mL and 95% at 10 ng/mL, respectively.

Conclusions

These results attest that Lumipulse G BRAHMS PCT exhibits excellent analytical performance, among the best of the methods currently available on the diagnostic market. However, the significant bias compared to the Vidas BRAHMS PCT suggests that the methods cannot be used interchangeably.

Economic evaluation of procalcitonin-guided antibiotic therapy in acute respiratory infections: a US health system perspective

BACKGROUND

Whether or not antibiotic stewardship protocols based on procalcitonin levels results in cost savings remains unclear. Herein, our objective was to assess the economic impact of adopting procalcitonin testing among patients with suspected acute respiratory tract infection (ARI) from the perspective of a typical US integrated delivery network (IDN) with a 1,000,000 member catchment area or enrollment.

METHODS

To conduct an economic evaluation of procalcitonin testing versus usual care we built a cost-impact model based on patient-level meta-analysis data of randomized trials. The meta-analytic data was adapted to the US setting by applying the meta-analytic results to US lengths of stay, costs, and practice patterns. We estimated the annual ARI visit rate for the one million member cohort, by setting (inpatient, ICU, outpatient) and ARI diagnosis.

RESULTS

In the inpatient setting, the costs of procalcitonin-guided compared to usual care for the one million member cohort was $2,083,545, compared to $2,780,322, resulting in net savings of nearly $700,000 to the IDN for 2014. In the ICU and outpatient settings, savings were $73,326 and $5,329,824, respectively, summing up to overall net savings of $6,099,927 for the cohort. RESULTS were robust for all ARI diagnoses. For the whole US insured population, procalcitonin-guided care would result in $1.6 billion in savings annually.

CONCLUSIONS

Our results show substantial savings associated with procalcitonin protocols of ARI across common US treatment settings mainly by direct reduction in unnecessary antibiotic utilization. These results are robust to changes in key parameters, and the savings can be achieved without any negative impact on treatment outcomes.

Analytical evaluation of Diazyme procalcitonin (PCT) latex-enhanced immunoturbidimetric assay on Beckman Coulter AU5800

BACKGROUND

This study was aimed to evaluate the analytical performance of the novel Diazyme procalcitonin (PCT) immunoturbidimetric assay on Beckman Coulter AU5800.

METHODS

Diazyme PCT is a latex-enhanced immunoturbidimetric assay, developed for use on laboratory instrumentations with capability of reading absorbance at 600 nm. This analytical evaluation included the assessment of limit of blank (LOB), limit of detection (LOD), functional sensitivity, imprecision, linearity, carryover, and method comparison between Diazyme PCT and Kryptor PCT on 129 routine serum inpatient samples.

RESULTS

The LOB, LOD, and functional sensitivity of Diazyme PCT were 0.16, 0.26, and 0.28 ng/mL, respectively. The intra- and inter-assay imprecision of Diazyme PCT was between 2.9% and 7.8%. The linearity was excellent in the range of PCT values between 0.16 and 56 ng/mL, and the carryover was negligible (0.02%). A highly significant agreement was found between Kryptor PCT and Diazyme PCT in a range of concentrations between 0.16 and 111 ng/mL (Diazyme PCT=1.10×Kryptor PCT-0.89; r=0.960; p<0.001). The mean bias was 0.48 ng/mL (95% CI, -0.58 to 1.54 ng/mL). The strength of agreement between Kryptor PCT and Diazyme PCT was between 85% and 96% at 0.50, 2.0, and 10 ng/mL cutoffs.

CONCLUSIONS

Diazyme PCT appears to be a reliable assay for diagnosis and management of critical care patients susceptible to severe bacterial infections.

Multicenter comparison of automated procalcitonin immunoassays

Objectives

A multicenter study to compare results of BRAHMS Kryptor PCT with those obtained using four BRAHMS-partnered procalcitonin (PCT) automated immunoassays (DiaSorin Liaison, BioMérieux Vidas, Roche Cobas E601 and Siemens Advia Centaur) and the Diazyme immunotubidimetric assay implemented on four clinical chemistry platforms (Abbott Architect c16000, Siemens Advia 2400, Roche Cobas C501 and Beckman Coulter AU5800).

Design and methods

One hundred serum samples from in-patients with PCT values between 0.10 and 58.7 ng/mL were divided into aliquots and tested with the nine different reagents and analyzers. BRAHMS PCT Kryptor results were used as reference.

Results

Compared to BRAHMS PCT Kryptor, significant differences in results were observed on Vidas, Advia Centaur, Architect, Cobas C501 and AU5800. However, the correlation coeffiecients (r) with BRAHMS PCT Kryptor were between 0.899 and 0.988. The mean bias was less than ±1.02 ng/mL, except for Vidas (2.70 ng/mL). The agreement at three clinically relevant cut-offs was optimal: between 83–98% at 0.50 ng/mL, 90–97% at 2.0 ng/mL, and 98% at 10 ng/mL. The comparison of Diazyme PCT across the four clinical chemistry analyzers yielded high correlation coefficients (r between 0.952 and 0.976), a mean bias less than ±0.9 ng/mL, acceptable agreement at 0.5 ng/mL (>82%), and high concordance at the 2.0 ng/mL (>97%) and 10 ng/mL (>98%) cut-offs.

Conclusions

The methods and applications evaluated in this multicenter study are aligned with BRAHMS PCT Kryptor and can be used for predicting the risk of progression to systemic inflammation in patients with bacterial infections using the conventional PCT diagnostic thresholds.

Red blood cell distribution width: A simple parameter with multiple clinical applications

The red blood cell distribution width (RDW) is a simple and inexpensive parameter, which reflects the degree of heterogeneity of erythrocyte volume (conventionally known as anisocytosis), and is traditionally used in laboratory hematology for differential diagnosis of anemias. Nonetheless, recent evidence attests that anisocytosis is commonplace in human disorders such as cardiovascular disease, venous thromboembolism, cancer, diabetes, community-acquired pneumonia, chronic obstructive pulmonary disease, liver and kidney failure, as well as in other acute or chronic conditions. Despite some demographic and analytical issues related to the routine assessment that may impair its clinical usefulness, an increased RDW has a high negative predictive value for diagnosing a variety of disorders, but also conveys important information for short- and long-term prognosis. Even more importantly, the value of RDW is now being regarded as a strong and independent risk factor for death in the general population. Although it has not been definitely established whether an increased value of RDW is a risk factor or should only be considered an epiphenomenon of an underlying biological and metabolic imbalance, it seems reasonable to suggest that the assessment of this parameter should be broadened far beyond the differential diagnosis of anemias. An increased RDW mirrors a profound deregulation of erythrocyte homeostasis involving both impaired erythropoiesis and abnormal red blood cell survival, which may be attributed to a variety of underlying metabolic abnormalities such as shortening of telomere length, oxidative stress, inflammation, poor nutritional status, dyslipidemia, hypertension, erythrocyte fragmentation and alteration of erythropoietin function. As such, the aim of this article is to provide general information about RDW and its routine assessment, to review the most relevant implications in health and disease and give some insights about its potential clinical applications.

Adherence to therapeutic guidelines for patients with community-acquired pneumonia in Australian hospitals

Community-acquired pneumonia (CAP) is a significant cause of morbidity and mortality, particularly in elderly patients, and is associated with a considerable economic burden on the healthcare system. The combination of high incidence and substantial financial costs necessitate accurate diagnosis and appropriate management of patients admitted with CAP. This article will discuss the rates of adherence to clinical guidelines, the use of severity scoring tools and the appropriateness of antimicrobial prescribing for patients diagnosed with CAP. The authors maintain that awareness of national and hospital guidelines is imperative to complement the physicians’ clinical judgment with evidence-based recommendations. Increased use of pneumonia severity assessment tools and greater adherence to therapeutic guidelines will enhance concordant antimicrobial prescribing for patients with CAP. A robust and multifaceted educational intervention, in combination with antimicrobial stewardship programs, may enhance compliance of CAP guidelines in clinical practice in Australia.

Novel diagnostics for aggravating pancreatic fistulas at the acute phase after pancreatectomy

AIM: To identify sensitive predictors of clinically relevant postoperative pancreatic fistula (POPF) at the acute phase after pancreatectomy.

METHODS: This study included 153 patients diagnosed as having POPFs at postoperative day (POD) 3 after either open pancreatoduodenectomy or distal pancreatectomy between January 2008 and March 2013. The POPFs were categorized into three grades based on the International Study Group on Pancreatic Fistula Definition, and POPFs of grades B or C were considered to be clinically relevant. The predictive performance for the clinically relevant POPF formation of values at PODs 1, 3 and 5 as well as time-dependent changes in levels of inflammatory markers, including white blood cell count, neutrophil count, total lymphocyte count, C-reactive protein (CRP), procalcitonin level, platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio, and amylase content in the drain fluid were compared using the receiver operating characteristic (ROC) curve and multivariable analyses. A scoring system for the prediction of clinically relevant POPFs was created using five risk factors identified in this study, and its diagnostic performance was also evaluated.

RESULTS: Over time, 77 (50%) of 153 enrolled patients followed a protracted course and were categorized as having clinically relevant POPFs. ROC curve analyses revealed that changes in CRP levels from POD 1 to POD 3 had the greatest area under the curve value (0.767) and that an elevated CRP level of 28.4 mg/L yielded the most optimal predictive value for clinically relevant POPFs. Multivariable analyses for the risk factors of clinically relevant POPFs identified invasive carcinomas of the pancreas and elevation of the CRP level (≥ 28.4 mg/L, from POD 1 to POD 3) as independent diagnostic factors for clinically relevant POPFs (OR 2.94, 95%CI: 1.08-8.55, P = 0.035 and OR 4.82, 95%CI: 1.25-20.2, P = 0.022, respectively). A gradual increase in the prevalence of clinically relevant POPFs in proportion to the risk classification score was confirmed. A highly elevated CRP level and a risk score ≥ 8 were significantly associated with a prolonged duration of drain placement and postoperative hospitalization.

CONCLUSION: A steep rise in the serum CRP level from POD 1 to POD 3 was a highly predictive factor for subsequent clinically relevant POPFs.

Overview of community-acquired pneumonia and the role of inflammatory mechanisms in the immunopathogenesis of severe pneumococcal disease

Community-acquired pneumonia (CAP) remains a leading cause of morbidity and mortality among the infectious diseases. Despite the implementation of national pneumococcal polyvalent vaccine-based immunisation strategies targeted at high-risk groups, Streptococcus pneumoniae (the pneumococcus) remains the most common cause of CAP. Notwithstanding the HIV pandemic, major challenges confronting the control of CAP include the range of bacterial and viral pathogens causing this condition, the ever-increasing problem of antibiotic resistance worldwide, and increased vulnerability associated with steadily aging populations in developed countries. These and other risk factors, as well as diagnostic strategies, are covered in the first section of this review. Thereafter, the review is focused on the pneumococcus, specifically the major virulence factors of this microbial pathogen and their role in triggering overexuberant inflammatory responses which contribute to the immunopathogenesis of invasive disease. The final section of the review is devoted to a consideration of pharmacological, anti-inflammatory strategies with adjunctive potential in the antimicrobial chemotherapy of CAP. This is focused on macrolides, corticosteroids, and statins with respect to their modes of anti-inflammatory action, current status, and limitations.

Serum C-reactive protein as a diagnostic biomarker in dogs with bacterial respiratory diseases

Background

C‐reactive protein (CRP) is a major acute‐phase protein in dogs. Serum concentrations are low in healthy animals, but increase rapidly after inflammatory stimuli.

Objective

The aim of the study was to investigate CRP concentrations in various respiratory diseases of dogs and to determine if CRP can be used as a biomarker in the diagnosis of bacterial respiratory diseases.

Animals

A total of 106 privately owned dogs with respiratory diseases (17 with bacterial tracheobronchitis [BTB], 20 with chronic bronchitis [CB], 20 with eosinophilic bronchopneumopathy [EBP], 12 with canine idiopathic pulmonary fibrosis [CIPF], 15 with cardiogenic pulmonary edema [CPE], and 22 with bacterial pneumonia [BP]) and 72 healthy controls.

Methods

The study was conducted as a prospective cross‐sectional observational study. CRP was measured in serum samples. Diagnosis was confirmed by clinical and laboratory findings, diagnostic imaging, and selected diagnostic methods such as cytological and microbiological analysis of respiratory samples, echocardiography, and histopathology.

Results

Dogs with BP had significantly higher CRP concentrations (median, 121 mg/L; interquartile range, 68–178 mg/L) than dogs with BTB (23, 15–38, P = .0003), CB (13, 8–14, P < .0001), EBP (5, 5–15, P < .0001), CIPF (17, 10–20, P < .0001), or CPE (19, 13–32, P < .0001) and healthy controls (14, 8–20, P < .0001). Dogs with BTB had significantly higher CRP concentrations than dogs with CB (P = .001) or EBP (P < .0001) and healthy controls (P = .029).

Conclusion and Clinical Importance

These results indicate that CRP has potential for use as an additional biomarker, especially in the diagnostics of BP.

Community-acquired pneumonia

PURPOSE OF REVIEW

Community-acquired pneumonia (CAP) contributes significantly to morbidity and mortality, especially in the elderly. Recent advances aimed at improving outcomes and reducing CAP disease burden are summarized.

RECENT FINDINGS

Emerging data suggests that newer CAP risk stratification indices based on disease severity hold promise in predicting intensive care need. Additional evidence supports a role of procalcitonin and pro-adrenomedullin as biomarkers of disease severity and for guiding antimicrobial therapy. New diagnostic tools have greatly contributed to early diagnosis and better-targeted therapy. There is increasing recognition of the role of coinfections in CAP. In patients with severe disease, therefore, current guidelines advise against monotherapy. Although inclusion of coverage for atypical pathogens in nonsevere CAP has been challenged, evidence suggests that such coverage is beneficial in patients with severe disease. Use of steroids as adjunctive therapy for CAP, however, is associated with complications and prolonged hospitalization. Updated prevention strategies include approval of pneumococcal conjugate vaccine (PCV13) for adults at risk.

SUMMARY

Despite these developments research aimed at further reducing CAP-related morbidity and mortality is required. Increasing global life expectancy is likely to expand the at-risk population; therefore, research directed at CAP prevention in view of changing demography is essential.

Diagnostics for community-acquired and atypical pneumonia

PURPOSE OF REVIEW

After decades of neglect, the importance of establishing an aetiological diagnosis for community-acquired and atypical pneumonias has increased dramatically in recent years--driven by the movement towards more rational use of antibiotics, the further spread of antimicrobial resistance, and advances in point-of-care assays that circumvent the diagnostic delays that result from the centralization of laboratories.

RECENT FINDINGS

There have been very few developments in patient sampling, or the direct visualization, culture, and serological detection of respiratory pathogens. There has, however, been significant interest in the development of improved and more clinically useful assays for the detection of pathogen nucleic acids and proteins, and also in the potential utility of the assessment of host response for tailoring therapy.

SUMMARY

The majority of patients have yet to benefit from any advances. However, nucleic acid, newer protein, and possibly host-response assays have significant potential to influence patient care in the near future.

Can an etiologic agent be identified in adults who are hospitalized for community-acquired pneumonia: results of a one-year study

INTRODUCTION

Determining the cause of community-acquired pneumonia (CAP) remains problematic. In this observational study, we systematically applied currently approved diagnostic techniques in patients hospitalized for CAP in order to determine the proportion in which an etiological agent could be identified.

METHODS

All patients admitted with findings consistent with CAP were included. Sputum and blood cultures, urine tests for pneumococcal and Legionella antigens, nasopharyngeal swab for viral PCR, and serum procalcitonin were obtained in nearly every case. Admission-related electronic medical records were reviewed in entirety.

RESULTS

By final clinical diagnosis, 44 patients (17.0%) were uninfected. A causative bacterium was identified in only 60 (23.2%) cases. PCR identified a respiratory virus in 42 (16.2%), 12 with documented bacterial coinfection. In 119 (45.9%), no cause for CAP was found; 69 (26.6%) of these had a syndrome indistinguishable from bacterial pneumonia. Procalcitonin was elevated in patients with bacterial infection and low in uninfected patients or those with viral infection, but with substantial overlap.

CONCLUSIONS

Only 23.2% of 259 patients admitted with a CAP syndrome had documented bacterial infection; another 26.6% had no identified bacterial etiology, but findings closely resembled those of bacterial infection. Nevertheless, all 259 received antibacterial therapy. Careful attention to the clinical picture may identify uninfected patients or those with viral infection, perhaps with reassurance by a non-elevated procalcitonin. Determining an etiologic diagnosis remains elusive. Better discriminators of bacterial infection are sorely needed.

Opinion paper on innovative approach of biomarkers for infectious diseases and sepsis management in the emergency department

Sepsis is a leading healthcare problem, accounting for the vast majority of fatal events in critically ill patients. Beyond early diagnosis and appropriate treatment, this condition requires a multifaceted approach for monitoring the severity, the potential organ failure as well as the risk of death. Monitoring of the efficacy of treatment is also a major issue in the emergency department (ED). The assessment of critically ill conditions and the prognosis of patients with sepsis is currently based on some scoring systems, which are, however, inefficient to provide definite clues about organ failure and prognosis in general. The discretionary and appropriate use of some selected biomarkers such as procalcitonin, inducible protein 10 (IP10), Group IV phospholipase A2 type II (PLA2 II), neutrophil gelatinase-associated lipocalin (NGAL), natriuretic peptides, mature adrenomedullin (ADM), mid-regional pro-adrenomedullin (MR-proADM), copeptin, thrombopoietin, Mer receptor and even red blood cell distribution width (RDW) represent thereby an appealing perspective in the diagnosis and management of patients with sepsis. Nevertheless, at the moment, it is not still clear if it is better to use a multimarkers approach or if a single, most appropriate, biomarker exists. This collective opinion paper is aimed at providing an overview about the potential clinical usefulness of some innovative biomarkers of sepsis in its diagnosis and prognosis, but also in the treatment management of the disease. This manuscript represents a synopsis of the lectures of Third Italian GREAT Network Congress, that was hold in Rome, 15–19 October 2012.