Procalcitonin as an early indicator of outcome in sepsis: a prospective observational study

Predicting Mortality in Sepsis: The Role of Dynamic Biomarker Changes and Clinical Scores-A Retrospective Cohort Study

BACKGROUND

The prognostic value of baseline inflammatory markers in sepsis remains controversial, with conflicting evidence regarding their association with mortality. The dynamic changes in these markers over time might offer additional insights into disease progression and patient outcomes.

METHODS

This retrospective observational study included 138 patients with severe infections. The inflammatory biomarkers procalcitonin (PCT), C-reactive protein (CRP), and lactate (LAC) were measured at three time points: upon hospital admission (baseline), approximately 24-48 h after admission (second measurement; M2), and 48-72 h after admission (third measurement; M3). The primary outcome was 30-day mortality. A Mann-Whitney U test was used to compare the biomarker levels between the survivors and non-survivors. A Spearman's correlation was used to assess the relationships between the baseline parameters. A logistic regression and a receiver operating characteristic (ROC) curve analysis were employed to evaluate the prognostic value of the baseline markers and their dynamic changes.

RESULTS

The baseline LAC and SOFA score were significantly associated with 30-day mortality. The percentage decrease in PCT, CRP, and LAC from the baseline to M3 emerged as strong predictors of survival, with the ROC curve analysis demonstrating superior discriminatory ability compared to the baseline values. CRP_Delta exhibited the highest AUC (0.903), followed by PCT_Delta (0.843) and LAC_Delta (0.703).

CONCLUSIONS

The dynamic changes in these inflammatory biomarkers, particularly PCT, CRP, and LAC, offer valuable prognostic information beyond their baseline levels in predicting 30-day mortality in severe infections. These findings highlight the importance of monitoring biomarker trends for early risk stratification and potential treatment guidance.

Current Status of Antibiotic Stewardship and the Role of Biomarkers in Antibiotic Stewardship Programs

The importance of antibiotic stewardship is increasingly emphasized in accordance with the increasing incidences of multidrug-resistant organisms and accompanying increases in disease burden. This review describes the obstacles in operating an antibiotic stewardship program (ASP), and whether the use of biomarkers within currently available resources can help. Surveys conducted around the world have shown that major obstacles to ASPs are shortages of time and personnel, lack of appropriate compensation for ASP operation, and lack of guidelines or appropriate manuals. Sufficient investment, such as the provision of full-time equivalent ASP practitioners, and adoption of computerized clinical decision systems are useful measures to improve ASP within an institution. However, these methods are not easy in terms of both time commitments and cost. Some biomarkers, such as C-reactive protein, procalcitonin, and presepsin are promising tools in ASP due to their utility in diagnosis and forecasting the prognosis of sepsis. Recent studies have demonstrated the usefulness of algorithmic approaches based on procalcitonin level to determine the initiation or discontinuation of antibiotics, which would be helpful in decreasing antibiotics use, resulting in more appropriate antibiotics use.

Association between admission serum procalcitonin and the occurrence of acute kidney injury in patients with septic shock: A retrospective cohort study

BACKGROUND

Procalcitonin (PCT) is an effective and sensitive diagnostic biomarker that can facilitate the early detection of infection and septicemia, but whether it can similarly be utilized to predict the development of acute kidney injury (AKI) in patients suffering from septic shock remains to be established. Herein, the relationship between serum PCT at admission and the onset of AKI in septic shock patients was thus evaluated following adjustment for other potential covariates.

METHODS

This was a retrospective cohort study of 303 septic shock patients treated in a Chinese hospital between May 2015 and May 2019. All patients in whom PCT levels were measured on admission and who did not exhibit AKI or chronic kidney disease at the time of admission were assessed for AKI development within one week following intensive care unit (ICU) admission as per the KDIGO criteria. The relationship between serum PCT at admission and AKI incidence was then assessed for these patients.

RESULTS

These 303 patients were an average of 64 years old, and were 59.7% male. Of these patients, 50.5% developed AKI within the first 7 days following ICU admission. A dully-adjusted binary logistic regression analysis revealed PCT levels at admission to be associated with AKI following adjustment for potential confounding factors (odds ratio (OR) = 1.01, 95%CI (1.01,1.02), p = 0.0007). Receiver operating characteristic curve analysis further indicated that a PCT cutoff level of 52.59 ng/ml at admission was able to predict the incidence of AKI with respective sensitivity and specificity values of 50% and 84%. Interaction analysis revealed no significant interactive relationship between PCT and AKI, suggesting that serum PCT levels represent an early predictor of AKI incidence in septic shock patients.

CONCLUSIONS

Serum PCT at the time of admission can be used as a predictor of AKI in patients suffering from septic shock.

Procalcitonin in clinical practice: from diagnosis of sepsis to antibiotic therapy

A diagnostic algorithm that allows for the rapid identification of sepsis and possibly guides the appropriate antimicrobial therapy application is the cornerstone to obtaining effective treatment and better results. The use of emerging surrogate markers could significantly improve clinical practice, but the validity and clinical utility have been proved only for very few of them, and their availability in clinical routine is limited. For this purpose, numerous scientific evidence has indicated procalcitonin as a marker linked to sepsis and its evolution. This review aims to retrace the main evidence relating to the use of procalcitonin in sepsis. We analyzed the primary studies in the literature and the existing meta-analysis evaluating the behavior of procalcitonin as a marker of bacterial sepsis, its prognostic power, and its ability to influence antibiotic therapy. Recent evidence has suggested that procalcitonin could be an efficient marker for diagnosing sepsis and its therapeutic management in many types of patients. The choice of the appropriate timing to initiate and suspend antibiotic therapy, with obvious clinical advantages, the favorable effects could also include reducing health costs, both avoiding the administration of inappropriate antibiotic therapies, and reducing the duration of hospitalization. Moreover, limited studies reported high procalcitonin levels in coronavirus disease 2019 patients with a worse prognosis. Despite the considerable evidence in favor of the potential of procalcitonin as an index for managing septic patients, there are conflicting data that deserve specific and detailed studies.

Should serial monitoring of procalcitonin be done routinely in critically ill patients of ICU: A systematic review and meta-analysis

Sepsis is a life-threatening condition with dysregulated host response to infection. It is a major determinant of mortality in the intensive care unit (ICU). Procalcitonin (PCT) is widely investigated for prognosis in patients with sepsis. Most of the studies have cited that elevated PCT concentrations and PCT non-clearance are associated with poor outcomes in patients with sepsis and some studies have cited as having no additional benefit. Most of the studies have evaluated single PCT measurement and correlated with prognosis and outcome in septic patients. Limited literature is there about serial PCT levels and its impact on the outcome of patients with sepsis. We searched literature through PubMed, Embase, Web of Knowledge, and the Cochrane Library from 2007 to 2017 and present a systematic review and meta-analysis of studies evaluating the utility of serial measurement of PCT for prognosis in critically ill patients. Articles that assessed PCT non-clearance as a marker of mortality data were included. The primary objective of this meta-analysis was to pool the results of all the available studies on serial PCT non-clearance as a mortality predictor and formulate overall area under receiver operating curve (AUROC). To find out the overall proportion of mortality in PCT non-clearance was our secondary objective. To detect the mortality using PCT non-clearance, ROC curve analysis was done. Area under curve (AUC) of the studies was varying between 0.52 and 0.86. Overall AUC was observed 0.711 (95% confidence interval (CI): 0.662–0.760) under fixed effect model and 0.708 (95% CI: 0.648–0.769) under random effect model. There was moderate variation among the studies, i.e., I² 50.80% (95% CI: 0.00–80.42%). The overall proportion of mortality was 37.54% with much heterogeneity (I² 88.24%) among the studies. PCT non-clearance is a fair predictor of mortality. Further studies are needed to define optimal cut off point for PCT non-clearance in ICU patients with sepsis.

Sepsis Biomarkers

Biomarkers have been used in sepsis to assist with the diagnosis of disease as well as determining the severity of disease, that is, prognosis. These biomarkers are based on the presence of discrete molecules within the blood. Unfortunately, in 2020, a single biomarker does not have sufficient sensitivity and specificity to definitively rule in or rule out sepsis. Biomarkers have shown better performance in animal models of disease.

The use of procalcitonin in the determination of severity of sepsis, patient outcomes and infection characteristics

Objective

The primary objective of this study was to determine the correlation between procalcitonin values and illness severity by evaluating the degree of end organ dysfunction using the Sequential Organ Failure Assessment score, length of stay and the severity of sepsis (sepsis alone vs. septic shock), The hypothesis that procalcitonin values would be higher in sicker patients was formulated before data collection began. Secondary outcomes studied in relation to procalcitonin levels included infection characteristics such as the site of infection, microbial agent and dialysis dependent CKD.

Design

Unblinded retrospective cohort study. September 2014-December 2016.

Setting

364 patients with a diagnosis of sepsis or severe sepsis who were admitted to the general medical ward and ICU at Methodist Medical Center and Proctor Hospital in Peoria, Illinois, USA.

Results

This study demonstrates the following: Weak positive correlation between procalcitonin and SOFA score. Negligible correlation with length of stay. Higher values in patients who died than in patients who survived to discharge (p = 0.058). Sensitivity and specificity of procalcitonin for septic shock was 63 and 65% respectively. Sites typically infected by gram negative bacteria have higher procalcitonin values than sites infected by gram positive bacteria (p = 0.03). Higher procalcitonin in bacteremia than non-bacteremic infections (p = 0.004). Higher procalcitonin in dialysis-dependent CKD patients (p = 0.020).

Conclusions

Procalcitonin has a higher specificity for bacterial infections than other acute phase reactants. Although initial procalcitonin value may be helpful in the determination of illness severity, it is not always a reliable prognostic indicator and carries little significance as a standalone value. Procalcitonin values may be influenced by preexisting comorbid conditions such as chronic kidney disease, which are associated with higher procalcitonin values at baseline. Procalcitonin can provide invaluable information when viewed as one piece of a clinical puzzle, and is most powerful when the interpreting physician is aware of how values are influenced by the different clinical scenarios presented in this article.

Checking procalcitonin suitability for prognosis and antimicrobial therapy monitoring in burn patients

Background

Due to greater infection susceptibility, sepsis is the main cause of death in burn patients. Quick diagnosis and patient stratification, early and appropriated antimicrobial therapy, and focus control are crucial for patients' survival. On the other hand, superfluous extension of therapy is associated with adverse events and arousal of microbial resistance. The use of biomarkers, necessarily coupled with close clinical examination, may predict outcomes, stratifying patients who need more intensive care, and monitor the efficacy of antimicrobial therapy, allowing faster de-escalation or stop, reducing the development of resistance and possibly the financial burden, without increasing mortality. The aim of this work is to check the suitability of procalcitonin (PCT) to fulfill these goals in a large sample of septic burn patients.

Methods

One hundred and one patients, with 15% or more of total body surface area (TBSA) burned, admitted from January 2011 to December 2014 at Coimbra Burns Unit (CBU), in Portugal were included in the sample. All patients had a diagnosis of sepsis, according to the American Burn Association (ABA) criteria. The sample was factored by survival (68 survivors and 33 non-survivors). The maximum value of PCT in each day was used for statistical analysis. Data were summarized by location measures (mean, median, minimum, maximum, quartiles) and dispersion measures (standard error and range measures). Statistical analysis was performed with SPSS© 23.0 IBM© for Windows©.

Results

There were statistically significant differences between PCT levels of patients from the survivor and non-survivor groups during the first and the last weeks of hospitalization as well as during the first week after sepsis suspicion, being slightly higher during this period. During the first 7 days of antimicrobial therapy, PCT was always higher in the non-survivor, still without reaching statistical significance, but when the analysis was extended till the 15th day, PCT increased significantly, rapidly, and steadily, denouncing therapy failure.

Conclusion

Despite being not an ideal biomarker, PCT proved to have good prognostic power in septic burn patients, paralleling the evolution of the infectious process and reflecting the efficacy of antimicrobial therapy, and the inclusion of its serial dosing may be advised to reinforce antimicrobial stewardship programs at burn units; meanwhile, more accurate approaches are not available.

Relationship of Serum Procalcitonin, C-reactive Protein, and Lactic Acid to Organ Failure and Outcome in Critically Ill Pediatric Population

Objective:

To evaluate the clinical and prognostic utility of procalcitonin (PCT), C-reactive protein (CRP), and lactic acid in children admitted to the Pediatric Intensive Care Unit (PICU) of a university teaching hospital.

Materials and Methods:

Medical records of children (1 month–16 years) tested for serum PCT at the time of admission in the PICU of our hospital from July 1, 2013, to January 15, 2015, were reviewed. Within 24 h of admission, the Pediatric Risk of Mortality Score, blood cultures, white blood cell count, neutrophil counts, serum CRP, plasma lactic acid, and PCT were noted. Patient outcome was assessed at hospital discharge, and the patients were divided into nonsurvivors and survivors.

Results:

A total of 167 children being admitted to the PICU were enrolled. The median age of the study population was 3 years (0–16 years), with 58.6% being males. Nonsurvivors had significantly higher lactic acid (4.7 mmol/L [2.07–7.6]; P < 0.05) than that of the survivors (2 mmol/L [1.3–3]; P < 0.05). In addition, nonsurvivors (94.4%; P < 0.05) had greater incidence of multiple organ dysfunction syndrome (MODS) than that of the survivors (38.05%; P < 0.05). Binary logistic regression showed age, MODS, and lactic acid to be associated with mortality.

Conclusions:

This study found that in comparison to PCT and CRP, high plasma lactic acid levels are associated with the development of all-cause MODS and worse outcome in critically ill children admitted in PICU. Prediction of prognosis based on the lactic acid alone may contribute to improve patient management, but further studies are required to endorse our findings.

Biomarkers of Infectious Diseases

Infection is defined as a pathologic process caused by the invasion of normally sterile tissue or fluid or body cavity by pathogenic or potentially pathogenic microorganisms. Sepsis is defined as the presence of organ dysfunction occurring as the result of a dysregulated host response to an infection.

The Clinical Challenge of Sepsis Identification and Monitoring

Jean-Louis Vincent outlines why combinations of biomarkers will be central to the future of sepsis diagnosis.

In Search of a Cure for Sepsis: Taming the Monster in Critical Care Medicine

In spite of over half a century of research, sepsis still constitutes a major problem in health care delivery. Although advances in research have significantly increased our knowledge of the pathogenesis of sepsis and resulted in better prognosis and improved survival outcome, sepsis still remains a major challenge in modern medicine with an increase in occurrence predicted and a huge socioeconomic burden. It is generally accepted that sepsis is due to an initial hyperinflammatory response. However, numerous efforts aimed at targeting the proinflammatory cytokine network have been largely unsuccessful and the search for novel potential therapeutic targets continues. Recent studies provide compelling evidence that dysregulated anti-inflammatory responses may also contribute to sepsis mortality. Our previous studies on the role of regulatory T cells and phosphoinositide 3-kinases in sepsis highlight immunological approaches that could be explored for sepsis therapy. In this article, we review the current and emerging concepts in sepsis, highlight novel potential therapeutic targets and immunological approaches for sepsis treatment and propose a biphasic treatment approach for management of the condition.

Improved Sepsis Alert With a Telephone Call From the Clinical Microbiology Laboratory: A Clinical Trial

Early sepsis attention is a standard of care in many institutions and the role of different specialists is well recognized. However, the impact of a telephone call from a specialist in Clinical Microbiology upon blood cultures request has not been assessed to the best of our knowledge. We performed telephone calls followed by an interview with physicians and nurses in charge of adult patients (> 18 years old) whose blood cultures had just been received in the Microbiology Laboratory in a tertiary hospital. Patients were randomly classified in 2 different groups: group A (telephone call performed) and group B (no telephone call). At the end of the telephonic intervention, recommendations on the use of microbiology and biochemical tests as well as on the management and antibiotic therapy of sepsis were made if required. We included 300 patients. Of those fulfilling standard criteria of sepsis, 30.3% of the nurses and 50% of the physicians immediately recognized it. Advice to optimize the use of biochemical and microbiological tests was provided in 36% of the cases and to improve antimicrobial therapy in 57.6%. The median number of days of antibiotic use in groups A and B were, respectively, 6 days (IQR: 2-12) vs 9 days (IQR: 4-16) P = 0.008 and the median number of prescribed daily doses of antimicrobials (6 [IQR: 3-17] vs 10 [IQR: 5-22] P = 0.016) were lower in group A. We estimate a reduction, only in the use of antibiotic, of 1.8 million Euros per year. A telephone call with management advice, immediately after the arrival of blood cultures in the Microbiology Laboratory improves the recognition of sepsis and the use of diagnostic resources and reduces antimicrobial consumption and expenses.

Prognostic Value of Procalcitonin in Adult Patients with Sepsis: A Systematic Review and Meta-Analysis

Procalcitonin (PCT) has been widely investigated for its prognostic value in septic patients. However, studies have produced conflicting results. The purpose of the present meta-analysis is to explore the diagnostic accuracy of a single PCT concentration and PCT non-clearance in predicting all-cause sepsis mortality. We searched PubMed, Embase, Web of Knowledge and the Cochrane Library. Articles written in English were included. A 2 × 2 contingency table was constructed based on all-cause mortality and PCT level or PCT non-clearance in septic patients. Two authors independently evaluated study eligibility and extracted data. The diagnostic value of PCT in predicting prognosis was determined using a bivariate meta-analysis model. We used the Q-test and I² index to test heterogeneity. Twenty-three studies with 3,994 patients were included. An elevated PCT level was associated with a higher risk of death. The pooled relative risk (RR) was 2.60 (95% confidence interval (CI), 2.05–3.30) using a random-effects model (I² = 63.5%). The overall area under the summary receiver operator characteristic (SROC) curve was 0.77 (95% CI, 0.73–0.80), with a sensitivity and specificity of 0.76 (95% CI, 0.67–0.82) and 0.64 (95% CI, 0.52–0.74), respectively. There was significant evidence of heterogeneity for the PCT testing time (P = 0.020). Initial PCT values were of limited prognostic value in patients with sepsis. PCT non-clearance was a prognostic factor of death in patients with sepsis. The pooled RR was 3.05 (95% CI, 2.35–3.95) using a fixed-effects model (I² = 37.9%). The overall area under the SROC curve was 0.79 (95% CI, 0.75–0.83), with a sensitivity and specificity of 0.72 (95% CI, 0.58–0.82) and 0.77 (95% CI, 0.55–0.90), respectively. Elevated PCT concentrations and PCT non-clearance are strongly associated with all-cause mortality in septic patients. Further studies are needed to define the optimal cut-off point and the optimal definition of PCT non-clearance for accurate risk assessment.

Host response biomarkers in sepsis: the role of procalcitonin

Procalcitonin is the prohormone of calcitonin and present in minute quantities in health. However, during infection, its levels rise considerably and are correlated with the severity of the infection. Several assays have been developed for measurement of procalcitonin levels; in this article, we will briefly present the PCT-sensitive Kryptor(®) test (Brahms, Hennigsdorf, Germany), one of the most widely used assays for procalcitonin in recent studies. Many studies have demonstrated the value of procalcitonin levels for diagnosing sepsis and assessing disease severity. Procalcitonin levels have also been successfully used to guide antibiotic administration. However, procalcitonin is not specific for sepsis, and values need to be interpreted in the context of a full clinical examination and the presence of other signs and symptoms of sepsis.

Use of rapid diagnostic techniques in ICU patients with infections

Background

Infection is a common complication seen in ICU patients. Given the correlation between infection and mortality in these patients, a rapid etiological diagnosis and the determination of antimicrobial resistance markers are of paramount importance, especially in view of today's globally spread of multi drug resistance microorganisms. This paper reviews some of the rapid diagnostic techniques available for ICU patients with infections.

Methods

A narrative review of recent peer-reviewed literature (published between 1995 and 2014) was performed using as the search terms: Intensive care medicine, Microbiological techniques, Clinical laboratory techniques, Diagnosis, and Rapid diagnosis, with no language restrictions.

Results

The most developed microbiology fields for a rapid diagnosis of infection in critically ill patients are those related to the diagnosis of bloodstream infection, pneumonia -both ventilator associated and non-ventilator associated-, urinary tract infection, skin and soft tissue infections, viral infections and tuberculosis.

Conclusions

New developments in the field of microbiology have served to shorten turnaround times and optimize the treatment of many types of infection. Although there are still some unresolved limitations of the use of molecular techniques for a rapid diagnosis of infection in the ICU patient, this approach holds much promise for the future.

The discriminative capacity of soluble Toll-like receptor (sTLR)2 and sTLR4 in inflammatory diseases

Background

The extracellular domains of cytokine receptors are released during inflammation, but little is known about the shedding of Toll-like receptors (TLR) and whether they can be used as diagnostic biomarkers.

Methods

The release of sTLR2 and sTLR4 was studied in in-vitro stimulations, as well as in-vivo during experimental human endotoxemia (n = 11, 2 ng/kg LPS), and in plasma of 394 patients with infections (infectious mononucleosis, measles, respiratory tract infections, bacterial sepsis and candidemia) or non-infectious inflammation (Crohn’s disease, gout, rheumatoid arthritis, autoinflammatory syndromes and pancreatitis). Using C-statistics, the value of sTLR2 and sTLR4 levels for discrimination between infections and non-infectious inflammatory diseases, as well as between viral and bacterial infections was analyzed.

Results

In-vitro, peripheral blood mononuclear cells released sTLR2 and sTLR4 by exposure to microbial ligands. During experimental human endotoxemia, plasma concentrations peaked after 2 hours (sTLR4) and 4 hours (sTLR2). sTLR4 did not correlate with cytokines, but sTLR2 correlated positively with TNFα (r_s = 0.80, P < 0.05), IL-6 (r_s = 0.65, P < 0.05), and IL-1Ra (r_s = 0.57, P = 0.06), and negatively with IL-10 (r_s = -0.58, P = 0.06), respectively. sTLR4 had a similar area under the ROC curve [AUC] for differentiating infectious and non-infectious inflammation compared to CRP: 0.72 (95% CI 0.66-0.79) versus 0.74 (95% CI 0.69-0.80) [P = 0.80], while sTLR2 had a lower AUC: 0.60 (95% CI 0.54-0.66) [P = 0.0004]. CRP differentiated bacterial infections better from viral infections than sTLR2 and sTLR4: AUC 0.94 (95% CI 0.90-0.96) versus 0.58 (95% CI 0.51-0.64) and 0.75 (95% CI 0.70-0.80), respectively [P < 0.0001 for both].

Conclusions

sTLRs are released into the circulation, and suggest the possibility to use sTLRs as diagnostic tool in inflammatory conditions.

Personalized CHF treatment: PCT to guide therapy in heart failure patients

Sorting out the etiology of dyspnea in patients with a history of heart failure is not always straightforward. Although an acute heart failure exacerbation would seem to be easy to distinguish from an acute respiratory illness, data from objective clinical studies has shown otherwise. Procalcitonin (PCT), a biomarker that rises in the setting of bacterial infection, carries great potential for guiding the diagnosis and treatment of heart failure patients with possible acute respiratory infection. In this issue of the International Journal of Cardiology, Kutz et al. demonstrated that patients with a history of heart failure and suspected lower respiratory tract infection experienced reduced antibiotic duration and superior outcomes with PCT-guided therapy. The results in this subset of heart failure patients from the ProHOSP study were consistent with the results seen in the overall study population. This study points to the need for a randomized controlled trial in a broader population of heart failure patients with acute dyspnea, to further define the prominent role that PCT can play in more personalized medical treatments that can improve patient outcomes.

Evaluation of procalcitonin as a marker to predict antibiotic response in adult patients with acute appendicitis: a prospective observational study

BACKGROUND

The aim of the study was to investigate the value of serum procalcitonin (PCT) as a predictor of early antibiotic treatment response in patients with acute appendicitis. Procalcitonin is a biochemical marker that increases rapidly in cases of bacterial infection and sepsis; however, the benefit of PCT as a diagnostic tool in acute appendicitis has not been confirmed.

METHODS

Observations of PCT dynamics were conducted as part of a prospective clinical trial at Sahlgrenska University Hospital between May 2009 and February 2010 on adult patients with acute appendicitis treated with antibiotics as first-line therapy. Procalcitonin, C-reactive protein (CRP), and white blood cell count (WBC) were measured before administration of antibiotics and subsequently between 4-24 h following treatment.

RESULTS

Three hundred sixteen patients were included in the study. Almost 80% recovered on antibiotics without the need of surgery. Serum PCT concentrations before initiation of antibiotic therapy and during treatment did not differ significantly between antibiotic responders and non-responders (p<0.94). However, differences were observed for CRP (p<0.04) and WBC (p<0.001), with a trend for body temperature (p<0.06).

CONCLUSION

Procalcitonin has limited additional value, compared with standard laboratory tests as CRP, WBC, and body temperature to predict antibiotic treatment response in adult patients with acute appendicitis.

Pro-adrenomedullin, pro-endothelin-1, procalcitonin, C-reactive protein and mortality risk in critically ill children: a prospective study

Introduction

We tested the hypothesis that higher mid-regional pro-adrenomedullin (MR-proADM), carboxy-terminal pro-endothelin-1 (CT-proET-1), procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations would be associated with increased prediction of mortality risk scores.

Methods

Prospective observational study set in two pediatric intensive care units (PICUs). Two-hundred-thirty-eight patients were included. MR-proADM, CT-proET-1, PCT and CRP levels were compared between children with PRISM III and PIM 2 > p75 (Group A; n = 33) and the rest (Group B; n = 205).

Results

Median (range) MR-proADM levels were 1.39 nmol/L (0.52–12.67) in group A versus 0.54 (0.15–3.85) in group B (P < 0.001). CT-proET-1 levels were 172 pmol/L (27–500) versus 58 (4–447) (P < 0.001). PCT levels were 7.77 ng/mL (0.34–552.00) versus 0.28 (0.02–107.00) (P < 0.001). CRP levels were 6.23 mg/dL (0.08-28.25) versus 1.30 mg/dL (0.00-42.09) (P = 0.210). The area under the ROC curve (AUC) for the differentiation of group A and B was 0.87 (95% CI:0.81–0.821) for MR-proADM, 0.86 (95% CI:0.79–0.92) for CT-proET-1 and 0.84 (95% CI:0.74–0.94) for PCT. A MR-proADM > 0.79 nmol/L had 93% sensitivity and 76% specificity to differentiate groups, whereas a CT-proET-1 > 123 pmol/L had 77% sensitivity and 84% specificity, and a PCT concentration > 2.05 ng/mL had 80% sensitivity and specificity.

Conclusions

In critically ill children, high levels of MR-proADM, CT-proET-1 and PCT were associated with increased prediction of mortality risk scores. MR-proADM, CT-proET-1 and PCT concentrations higher than 0.80 nmol/L, 123 pmol/L and 2 ng/mL, respectively, could be used by clinicians to identify critically ill children at higher prediction of risk death scores.

Diagnostic and prognostic markers in sepsis

Sepsis is a common and serious complication in intensive care unit patients. An important factor in optimizing survival rates in septic patients is the ability to start treatment early in the course of disease; there is, therefore, a need for accurate diagnostic tests. In recent years, there has been a move away from the rather vague and nonspecific signs that were previously used to diagnose sepsis towards the possible adjunctive role of biomarkers. Many biomarkers have been proposed and assessed clinically, but none alone is specific enough to definitively determine diagnosis. The future direction of research is most likely a greater focus on the use of panels or combinations of markers with clinical signs. Some biomarkers may also be useful for prognosis and guiding therapy. Here, the authors will review our changing approaches to sepsis diagnosis and discuss some of the markers that seem most relevant at the present time.

Diagnostic value of dynamics serum sCD163, sTREM-1, PCT, and CRP in differentiating sepsis, severity assessment, and prognostic prediction

Objective. To describe the dynamics changes of sCD163, soluble serum triggering receptor expressed on myeloid cells-1 (sTREM-1), procalcitonin (PCT), and C-reactive protein (CRP) during the course of sepsis, as well as their outcome prediction. Patients and Methods. An SIRS group (30 cases) and a sepsis group (100 cases) were involved in this study. Based on a 28-day survival, the sepsis was further divided into the survivors' and nonsurvivors' groups. Serum sTREM-1, sCD163, PCT, CRP, and WBC counts were tested on days 1, 3, 5, 7, 10, and 14. Results. On the ICU admission, the sepsis group displayed higher levels of sTREM-1, sCD163, PCT, and CRP than the SIRS group (P < 0.05). Although PCT and sTREM-1 are good markers to identify severity, sTREM-1 is more reliable, which proved to be a risk factor related to sepsis. During a 14-day observation, sCD163, sTREM-1, PCT, and SOFA scores continued to climb among nonsurvivors, while their WBC and CRP went down. Both sCD163 and SOFA scores are risk factors impacting the survival time. Conclusion. With regard to sepsis diagnosis and severity, sTREM-1 is more ideal and constitutes a risk factor. sCD163 is of a positive value in dynamic prognostic assessment and may be taken as a survival-impacting risk factor.

Value of soluble TREM-1, procalcitonin, and C-reactive protein serum levels as biomarkers for detecting bacteremia among sepsis patients with new fever in intensive care units: a prospective cohort study

Background

The purpose of this study was to explore the diagnostic value of soluble triggering receptor expressed on myeloid cells 1 (sTREM-1), procalcitonin (PCT), and C-reactive protein (CRP) serum levels for differentiating sepsis from SIRS, identifying new fever caused by bacteremia, and assessing prognosis when new fever occurred.

Methods

We enrolled 144 intensive care unit (ICU) patients: 60 with systemic inflammatory response syndrome (SIRS) and 84 with sepsis complicated by new fever at more than 48 h after ICU admission. Serum sTREM-1, PCT, and CRP levels were measured on the day of admission and at the occurrence of new fever (>38.3°C) during hospitalization. Based on the blood culture results, the patients were divided into a blood culture-positive bacteremia group (33 patients) and blood culture-negative group (51 patients). Based on 28-day survival, all patients, both blood culture-positive and -negative, were further divided into survivor and nonsurvivor groups.

Results

On ICU day 1, the sepsis group had higher serum sTREM-1, PCT, and CRP levels compared with the SIRS group (P <0.05). The areas under the curve (AUC) for these indicators were 0.868 (95% CI, 0.798–0.938), 0.729 (95% CI, 0.637–0.821), and 0.679 (95% CI, 0.578–0.771), respectively. With 108.9 pg/ml as the cut-off point for serum sTREM-1, sensitivity was 0.83 and specificity was 0.81. There was no statistically significant difference in serum sTREM-1 or PCT levels between the blood culture-positive and -negative bacteremia groups with ICU-acquired new fever. However, the nonsurvivors in the blood culture-positive bacteremia group had higher levels of serum sTREM-1 and PCT (P <0.05), with a prognostic AUC for serum sTREM-1 of 0.868 (95% CI, 0.740–0.997).

Conclusions

Serum sTREM-1, PCT, and CRP levels each have a role in the early diagnosis of sepsis. Serum sTREM-1, with the highest sensitivity and specificity of all indicators studied, is especially notable. sTREM-1, PCT, and CRP levels are of no use in determining new fever caused by bacteremia in ICU patients, but sTREM-1 levels reflect the prognosis of bacteremia.

Trial registration

ClinicalTrial.gov identifier NCT01410578

Brain natriuretic peptide for prediction of mortality in patients with sepsis: a systematic review and meta-analysis

Introduction

Early identification of septic patients at high risk of dying remains a challenge. The prognostic role of brain natriuretic peptide (BNP) or N-terminal pro-B-type natriuretic peptide (NT-proBNP) in septic patients remains controversial. The purpose of this systematic review and meta-analysis was to investigate the value of elevated BNP or NT-proBNP in predicting mortality in septic patients.

Methods

PubMed, Embase and the Cochrane Central Register of Controlled Trials were searched (up to February 18, 2011). Studies were included if they had prospectively collected data on all-cause mortality in adult septic patients with either plasma BNP or NT-proBNP measurement. Studies that failed to construct a 2 × 2 table of results were excluded. Two authors independently determined the validity of included studies and extracted data.

Results

12 studies with a total of 1,865 patients were included. Elevated natriuretic peptides were significantly associated with increased risk of mortality (odds ratio (OR) 8.65, 95% confidence interval (CI) 4.94 to 15.13, P < 0.00001). The association was consistent for BNP (OR 10.44, 95% CI 4.99 to 21.58, P < 0.00001) and NT-proBNP (OR 6.62, 95% CI 2.68 to 16.34, P < 0.0001). The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were 79% (95% CI 75 to 83), 60% (95% CI 57 to 62), 2.27 (95% CI 1.83 to 2.81) and 0.32 (95% CI 0.22 to 0.46), respectively.

Conclusions

Our results suggested that an elevated BNP or NT-proBNP level may prove to be a powerful predictor of mortality in septic patients. Future larger and more adequately powered prospective studies are warranted to clarify the assay standardization, the optimal cut-off, and the prognostic value of BNPs in conjunction with other biomarkers.

Procalcitonin in early onset ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) is a significant problem in intensive care and there exists great demand for a suitable biomarker. Procalcitonin (PCT) has been proposed as a candidate marker.

AIM

To assess the clinical usefulness of monitoring PCT concentrations in non-surgical patients with early onset VAP.

METHODS

Thirty-four patients were enrolled with early onset VAP defined as VAP diagnosed between 48 h and 6 days of the onset of mechanical ventilation. Serum PCT was measured on days 1, 2, 3, 5, 6 and 7.

FINDINGS

The mortality rate was 21%. Non-survivors had significantly elevated PCT levels on days 3 and 7. For non-survival, the areas under the receiver operator curve (AUC) for PCT were 0.762 [95% confidence interval (CI): 0.6-0.923] on day 3 and 0.754 (95% CI: 0.586-0.922) on day 7. Among septic patients, PCT was significantly higher on days 1, 2, 3, 5, and 7, with the highest AUC on day 1 (0.783; 95% CI: 0.626-0.94): a cut-off of 1 ng/mL on day 1 had a positive predictive value of 0.813 for the development of septic shock.

CONCLUSION

No association was found between PCT concentration and the adequacy of antibiotic therapy or the aetiology of VAP. In logistic regression analysis, PCT was not significantly correlated with poor outcome. Although PCT levels were higher in non-survivors and those who developed septic shock, PCT is not a strong predictor of these outcomes.

TREM-1 expression on neutrophils and monocytes of septic patients: relation to the underlying infection and the implicated pathogen

BACKGROUND

Current knowledge on the exact ligand causing expression of TREM-1 on neutrophils and monocytes is limited. The present study aimed at the role of underlying infection and of the causative pathogen in the expression of TREM-1 in sepsis.

METHODS

Peripheral venous blood was sampled from 125 patients with sepsis and 88 with severe sepsis/septic shock. The causative pathogen was isolated in 91 patients. Patients were suffering from acute pyelonephritis, community-acquired pneumonia (CAP), intra-abdominal infections (IAIs), primary bacteremia and ventilator-associated pneumonia or hospital-acquired pneumonia (VAP/HAP). Blood monocytes and neutrophils were isolated. Flow cytometry was used to estimate the TREM-1 expression from septic patients.

RESULTS

Within patients bearing intrabdominal infections, expression of TREM-1 was significantly lower on neutrophils and on monocytes at severe sepsis/shock than at sepsis. That was also the case for severe sepsis/shock developed in the field of VAP/HAP. Among patients who suffered infections by Gram-negative community-acquired pathogens or among patients who suffered polymicrobial infections, expression of TREM-1 on monocytes was significantly lower at the stage of severe sepsis/shock than at the stage of sepsis.

CONCLUSIONS

Decrease of the expression of TREM-1 on the membrane of monocytes and neutrophils upon transition from sepsis to severe sepsis/septic shock depends on the underlying type of infection and the causative pathogen.

Meta-analysis and systematic review of procalcitonin-guided therapy in respiratory tract infections

Circulating procalcitonin (PCT) is a biomarker that can be used in diagnosing bacterial infections. We performed a quantitative meta-analysis of available randomized controlled trials to determine whether antibiotic therapy based on PCT measurements alters clinical outcomes and antibiotic use in patients with lower respiratory tract infections. We identified studies through MEDLINE (1996 to 2010), the ISI Web of Knowledge (1996 to 2010), and Ovid. Studies that met our criteria were prospective, randomized controlled trials involving patients with respiratory tract infections. Outcomes of mortality, intensive care unit (ICU) admission, length of hospital stay, number of antibiotic prescriptions, and duration of antibiotic treatment were evaluated. Eight studies randomizing 3,431 patients met our criteria for inclusion. Pooled analysis showed a significant reduction in number of antibiotic prescriptions and duration of antibiotic use in patients with PCT-guided antibiotic treatment compared to standard therapy. In addition, the use of PCT-guided antibiotic therapy did not impact mortality, ICU admission, or length of hospital stay in these studies. A high degree of heterogeneity was identified in 3 of 5 outcomes that were evaluated, and sensitivity analysis indicated that heterogeneity was decreased among studies using the same PCT-based treatment algorithm. In conclusion, PCT-guided antibiotic therapy in patients with respiratory tract infections appears to reduce antibiotic use without affecting overall mortality or length of stay in the hospital.