Procalcitonin and C-reactive protein plasma concentrations in nonseptic uremic patients undergoing hemodialysis

Biomarkers in pulmonary infections: a clinical approach

Severe acute respiratory infections, such as community-acquired pneumonia, hospital-acquired pneumonia, and ventilator-associated pneumonia, constitute frequent and lethal pulmonary infections in the intensive care unit (ICU). Despite optimal management with early appropriate empiric antimicrobial therapy and adequate supportive care, mortality remains high, in part attributable to the aging, growing number of comorbidities, and rising rates of multidrug resistance pathogens. Biomarkers have the potential to offer additional information that may further improve the management and outcome of pulmonary infections. Available pathogen-specific biomarkers, for example, Streptococcus pneumoniae urinary antigen test and galactomannan, can be helpful in the microbiologic diagnosis of pulmonary infection in ICU patients, improving the timing and appropriateness of empiric antimicrobial therapy since these tests have a short turnaround time in comparison to classic microbiology. On the other hand, host-response biomarkers, for example, C-reactive protein and procalcitonin, used in conjunction with the clinical data, may be useful in the diagnosis and prediction of pulmonary infections, monitoring the response to treatment, and guiding duration of antimicrobial therapy. The assessment of serial measurements overtime, kinetics of biomarkers, is more informative than a single value. The appropriate utilization of accurate pathogen-specific and host-response biomarkers may benefit clinical decision-making at the bedside and optimize antimicrobial stewardship.

Acute Infections and Inflammatory Biomarkers in Patients with Acute Pulmonary Embolism

Although infections are frequent in patients with pulmonary embolism (PE), its effect on adverse outcome risk remains unclear. We investigated the incidence and prognostic impact of infections requiring antibiotic treatment and of inflammatory biomarkers (C-reactive protein [CRP] and procalcitonin [PCT]) on in-hospital adverse outcomes (all-cause mortality or hemodynamic insufficiency) in 749 consecutive PE patients enrolled in a single-centre registry. Adverse outcomes occurred in 65 patients. Clinically relevant infections were observed in 46.3% of patients and there was an increased adverse outcome risk with an odds ratio (OR) of 3.12 (95% confidence interval [CI] 1.70-5.74), comparable to an increase in one risk class of the European Society of Cardiology (ESC) risk stratification algorithm (OR 3.45 [95% CI 2.24-5.30]). CRP > 124 mg/dL and PCT > 0.25 µg/L predicted patient outcome independent of other risk factors and were associated with respective ORs for an adverse outcome of 4.87 (95% CI 2.55-9.33) and 5.91 (95% CI 2.74-12.76). In conclusion, clinically relevant infections requiring antibiotic treatment were observed in almost half of patients with acute PE and carried a similar prognostic effect to an increase in one risk class of the ESC risk stratification algorithm. Furthermore, elevated levels of CRP and PCT seemed to be independent predictors of adverse outcome.

How to use biomarkers of infection or sepsis at the bedside: guide to clinicians

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. In this context, biomarkers could be considered as indicators of either infection or dysregulated host response or response to treatment and/or aid clinicians to prognosticate patient risk. More than 250 biomarkers have been identified and evaluated over the last few decades, but no biomarker accurately differentiates between sepsis and sepsis-like syndrome. Published data support the use of biomarkers for pathogen identification, clinical diagnosis, and optimization of antibiotic treatment. In this narrative review, we highlight how clinicians could improve the use of pathogen-specific and of the most used host-response biomarkers, procalcitonin and C-reactive protein, to improve the clinical care of patients with sepsis. Biomarker kinetics are more useful than single values in predicting sepsis, when making the diagnosis and assessing the response to antibiotic therapy. Finally, integrated biomarker-guided algorithms may hold promise to improve both the diagnosis and prognosis of sepsis. Herein, we provide current data on the clinical utility of pathogen-specific and host-response biomarkers, offer guidance on how to optimize their use, and propose the needs for future research.

Clinical and microbiological characteristics of patients with bacteremia and normal procalcitonin

Procalcitonin is a biomarker of bacterial infection used to guide antimicrobial therapy. However, emerging studies have highlighted bacteremic patients with low procalcitonin, potentially limiting its clinical utility. Here, we conducted an observational, retrospective study analyzing clinical and microbiological parameters of adult patients with bacteremia and procalcitonin <2 ng/mL. High proportions of patients required intensive care (31.2%) with vasopressor (14.9%) or ventilatory (17.7%) support, developed renal injury (30.7%), or had in-hospital mortality (14.4%). When divided into subgroups by procalcitonin level, patients with procalcitonin 0.5 to 2.0 ng/mL had significantly higher rates of in-hospital mortality, vasopressor requirement, and renal injury than those with procalcitonin <0.5 ng/mL. Altogether, bacteremic patients had significant morbidity and mortality despite low procalcitonin. While subgroup analysis suggested that higher procalcitonin may correlate with illness severity, a more sensitive procalcitonin cutoff did not eliminate patients with significant disease. Procalcitonin-based algorithms may not be clinically appropriate for management of bacteremia.

Comparison of sPLA2IIA performance with high-sensitive CRP neutrophil percentage PCT and lactate to identify bacterial infection

Early bacterial infection (BI) identification in resource-limiting Emergency Departments (ED) is challenging, especially in low- and middle-income counties (LMIC). Misdiagnosis predisposes to antibiotic overuse and propagates antimicrobial resistance. This study evaluates new emerging biomarkers, secretory phospholipase A2 group IIA (sPLA2-IIA) and compares with other biomarkers on their performance characteristic of BI detection in Malaysia, an LMIC. A prospective cohort study was conducted involving 151 consecutive patients admitted to the ED. A single measurement was taken upon patient arrival in ED and was analysed for serum levels of sPLA2-IIA, high-sensitive C-reactive protein (CRP), procalcitonin (PCT), neutrophil percentage (N%), and lactate. All biomarkers' performance was compared for the outcomes using area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity. The performance of sPLA2-IIA (AUROC 0.93 [95% CI: 0.89-0.97]; Sn 80% [95% CI: 72-87]; Sp 94% [95% CI: 81-89]) was the highest among all. It was comparable with high-sensitive CRP (AUROC 0.93 [95% CI: 0.88-0.97]; Sn 75% [95% CI: 66-83]; Sp 91 [95% CI: 77-98]) but had a higher Sn and Sp. The sPLA2-IIA was also found superior to N%, PCT, and lactate. This finding suggested sPLA2-IIA was recommended biomarkers for BI detection in LMIC.

PCT Kinetics in the First Week Postburn for Sepsis Diagnosis and Death Prognosis-An Accuracy Study

Despite continuous advances in burn care, sepsis is still the main cause of death in burn patients. Procalcitonin (PCT) has been reported as an accurate sepsis biomarker and also as a fair predictor of death. The aim of this study was to assess PCT kinetics in the first week postburn regarding sepsis diagnosis and death prognosis. Sample included 142 patients with ≥15% TBSA, admitted from January 2011 to December 2014 at Coimbra Burns Unit, Portugal. Sepsis diagnosis was done according to American Burn Association criteria. PCT range and median values in the first 7 days after burns were statistically analyzed for its potential for sepsis diagnosis and death prognosis. A subanalysis was done regarding TBSA, sex, age, and inhalation injury. First week PCT range and median were significant for sepsis diagnosis and death prognosis, but the median area under the curve was greater in the last case. TBSA influenced PCT accuracy, which was greater for TBSA less than 40% either for diagnosis or prognosis. Age was inversely related to the accuracy, being better in younger than 40 years in both cases. PCT diagnostic accuracy was not affected by sex, opposing to the prognostic one which is better in women. Inhalation injury had no effect on diagnostic accuracy, but it happens with prognostic accuracy. PCT levels' variation is related to sepsis evolution and outcome. Its median performs better than its range. Always coupled with clinical examination, monitoring PCT levels kinetics may help early sepsis detection, potentially reducing morbidity and mortality, being also useful for death prognosis.

Diagnostic Accuracy of Procalcitonin and C-reactive Protein Is Insufficient to Predict Proven Infection: A Retrospective Cohort Study in Critically Ill Patients Fulfilling the Sepsis-3 Criteria

BACKGROUND

New Sepsis-3 definitions facilitate early recognition of patients with sepsis. In this study we investigated whether a single initial determination of procalcitonin (PCT) or C-reactive protein (CRP) in plasma can predict proven sepsis in Sepsis-3 criteria-positive critically ill patients. We also investigated whether a decline in serial PCT or CRP can predict outcome in 28-day mortality.

METHODS

Patients, ≥18 years of age, at the intensive care unit with a suspected infection, a Sequential Organ Failure Assessment (SOFA) score of ≥2 points, and an index test PCT and CRP at admission were selected from a prospectively collected cohort. PCT and CRP were studied retrospectively with the Mann-Whitney U-test and ROC analysis.

RESULTS

In total, 157 patients were selected; 63 of the 157 had proven sepsis, and sepsis could not be detected in 94 of the 157. Neither a single PCT nor CRP at admission was able to discriminate proven sepsis from nonproven sepsis (PCT, 1.8 μg/L and 1.5 μg/L, respectively, P = 0.25; CRP, 198 mg/L and 186 mg/L, respectively, P = 0.53). Area under the curve for both PCT and CRP for detecting proven sepsis was low (0.55 and 0.53). Furthermore, neither a decline from baseline to day 5 PCT nor CRP could predict 28-day mortality (PCT, 50% vs 46%, P = 0.83; CRP, 30% vs 40%, P = 0.51).

CONCLUSION

PCT and CRP at admission were not able to discern patients with proven sepsis in Sepsis-3 criteria-positive critically ill patients. A decline of PCT and CRP in 5 days was not able to predict 28-day mortality.

Procalcitonin in special patient populations: Guidance for antimicrobial therapy

PURPOSE

Procalcitonin (PCT) is an endogenous hormone that increases reliably in response to bacterial infection, and measurement of serum PCT levels is recommended to help guide antimicrobial therapy. The utility of PCT assessment in special patient populations (eg, patients with renal dysfunction, cardiac compromise, or immunocompromised states and those undergoing acute care surgery) is less clear. The evidence for PCT-guided antimicrobial therapy in special populations is reviewed.

SUMMARY

In the presence of bacterial infection, nonneuroendocrine PCT is produced in response to bacterial toxins and inflammatory cytokines, resulting in markedly elevated levels of serum PCT. Cytokine induction in nonbacterial inflammatory processes activated by acute care surgery may alter the interpretation of PCT levels. The reliability of PCT assessment has also been questioned in patients with renal dysfunction, cardiac compromise, or immunosuppression. In many special populations, serum PCT may be elevated at baseline and increase further in the presence of infection; thus, higher thresholds for diagnosing infection or de-escalating therapy should be considered, although the optimal threshold to use in a specific population is unclear. Procalcitonin-guided antimicrobial therapy may be recommended in certain clinical situations.

CONCLUSION

Procalcitonin may be a reliable marker of infection even in special populations with baseline elevations in serum PCT. However, due to unclear threshold values and the limited inclusion of special populations in relevant clinical trials, PCT levels should be considered along with clinical criteria, and antibiotics should never be initiated or withheld based on PCT values alone. Procalcitonin measurement may have a role in guiding de-escalation of antibiotic therapy in special populations; however, the clinician should be aware of disease states and concomitant therapies that may affect interpretation of results.

The Relationship between Serum Procalcitonin and Dialysis Adequacy in Peritoneal Dialysis Patients

Background:

To detect the serum procalcitonin (PCT) levels of peritoneal dialysis (PD) patients.

Methods:

We analyzed the relationship between the PCT Level and dialysis adequacy. We studied 120 peritoneal dialysis patients without signs of infection in Affiliated Hangzhou First People’s Hospital and 120 controls from Jan 2014 to Apr 2016. PCT and high sensitivity C-reactive protein (hs-CRP) were detected. 120 PD patients were divided into two groups according to the dialysis adequacy. A correlation analysis was processed between the PCT level and the total solute clearance (Kt/V). The value of PCT for identifying the dialysis adequacy in PD patients was assessed by ROC curve analysis.

Results:

PCT level in serum of PD group (0.29±0.24 ng/ml) was higher than that of the control group (0.02±0.01 ng/ml) (P<0.01). Compared with the inadequate dialysis group (0.5±0.37 ng/ml), the PCT Level of the adequate dialysis group (0.23±0.15 ng/ml) was lower (P<0.01). There were negative correlations between PCT and Kt/v(r=−0.451), Prealbumin (PA) (r=−0.258), Glomerular Filtration Rate (eGFR; r=−0.280), while there was positive correlation between PCT and Hypersensitive c-reactive protein (r=0.458) (P<0.01). At a serum PCT cut-off value of 0.283 ng/ml, the sensitivity and specificity for identifying the dialysis adequacy in PD patients were 0.913 and 0.805 respectively. The serum levels of PCT in peritoneal dialysis patients were significantly higher than the levels in healthy controls.

Conclusion:

The serum level of PCT can be used as an indirect maker to evaluate the adequacy of dialysis.

Early Laboratory Predictors for Necessity of Renal Replacement Therapy in Patients With Spontaneous Deep-Seated Intracerebral Hemorrhage

Objective: The need for continuous renal replacement therapy (CRRT) in patients with deep-seated intracerebral hemorrhage (ICH) requires sustained intensive care and often postpones further rehabilitation therapy. Therefore, an early identification of patients at risk is essential.

Methods: From 2014 to 2019, all patients with deep-seated ICH who were admitted to intensive care for >3 days were included in the further analysis and retrospectively reviewed for the need for CRRT. All patients underwent CRRT with regional citrate anticoagulation for continuous veno-venous hemodialysis (CVVHD). Outcome was evaluated after 3 months using the modified Rankin scale. A multivariate analysis was performed to identify potential predictors for CRRT in patients with deep-seated ICH.

Results: After applying the inclusion criteria, a total of 87 patients with deep-seated spontaneous ICH were identified and further analyzed. During the first 48 h after admission, 21 of these patients developed early acute kidney injury (AKI; 24%). During treatment course, CRRT became necessary in nine patients suffering from deep-seated ICH (10%). The multivariate analysis revealed “development of AKI during the first 48 h” [p = 0.025, odds ratio (OR) 6.1, 95% confidence interval (CI) 1.3–29.8] and “admission procalcitonin (PCT) value >0.5 μg/l” (p = 0.02, OR 7.7, 95% CI 1.4–43.3) as independent and significant predictors for CRRT in patients with deep-seated ICH.

Conclusions: Elevated serum levels of procalcitonin on admission as well as early development of acute renal injury are independent predictors of the need for renal replacement therapy in patients with deep-seated intracerebral bleeding. Therefore, further research is warranted to identify these vulnerable patients as early as possible to enable adequate treatment.

Procalcitonin as a Marker of Comorbid Atrial Fibrillation in Chronic Kidney Disease and History of Sepsis

Cardiovascular disease and infection are the leading causes of mortality in patients with stage 5 chronic kidney disease on hemodialysis (CKD5-HD). Inflammation is a large component in the pathogenesis of both atrial fibrillation (AF) and sepsis and may link these conditions in CKD5-HD. Procalcitonin (PCT) is an inflammatory biomarker elevated in systemic infection and CKD5-HD, yet its value with regard to comorbid AF has not been thoroughly investigated. The aim of this study sought to evaluate circulating inflammatory markers, including PCT, Angiopoietin-1, Angiopoetin-2, CD40-L, C-reactive protein, d-dimer, and von Willebrand factor in relation to these conditions. Plasma levels of inflammatory markers were measured by enzyme linked immunosorbent assay method in CKD5-HD (n = 97) patients and controls (n = 50). Procalcitonin levels were significantly elevated (P = .0270) in CKD5-HD with comorbid AF compared to those without AF. Further analysis of patients with a history of sepsis demonstrated significantly elevated levels of PCT (P = .0405) in those with comorbid AF (160.7 ± 39.5 pg/mL) compared to those without AF (117.4 ± 25.3 pg/mL). This study demonstrates that the inflammatory biomarker PCT is further elevated in the presence of both AF and a history of sepsis in hemodialysis patients and suggests that underlying chronic inflammation following sepsis resolution may place these patients at greater risk of developing AF.

Association of kidney function with effectiveness of procalcitonin-guided antibiotic treatment: a patient-level meta-analysis from randomized controlled trials

Objectives

Patients with impaired kidney function have a significantly slower decrease of procalcitonin (PCT) levels during infection. Our aim was to study PCT-guided antibiotic stewardship and clinical outcomes in patients with impairments of kidney function as assessed by creatinine levels measured upon hospital admission.

Methods

We pooled and analyzed individual data from 15 randomized controlled trials who were randomly assigned to receive antibiotic therapy based on a PCT-algorithms or based on standard of care. We stratified patients on the initial glomerular filtration rate (GFR, ml/min/1.73 m2) in three groups (GFR >90 [chronic kidney disease; CKD 1], GFR 15-89 [CKD 2-4] and GFR<15 [CKD 5]). The main efficacy and safety endpoints were duration of antibiotic treatment and 30-day mortality.

Results

Mean duration of antibiotic treatment was significantly shorter in PCT-guided (n=2,492) compared to control patients (n=2,510) (9.5-7.6 days; adjusted difference in days -2.01 [95% CI, -2.45 to -1.58]). CKD 5 patients had overall longer treatment durations, but a 2.5-day reduction in treatment duration was still found in patients receiving in PCT-guided care (11.3 vs. 8.6 days [95% CI -3.59 to -1.40]). There were 397 deaths in 2,492 PCT-group patients (15.9%) compared to 460 deaths in 2,510 control patients (18.3%) (adjusted odds ratio, 0.88 [95% CI 0.78 to 0.98)]. Effects of PCT-guidance on antibiotic treatment duration and mortality were similar in subgroups stratified by infection type and clinical setting (p interaction >0.05).

Conclusions

This individual patient data meta-analysis confirms that the use of PCT in patients with impaired kidney function, as assessed by admission creatinine levels, is associated with shorter antibiotic courses and lower mortality rates.

Determination of the Optimal Procalcitonin Threshold for Infection in Patients With Impaired Renal Function at a Community Hospital

Background: Procalcitonin (PCT) is a biomarker that can help identify bacterial infections but can be difficult to interpret in the presence of renal dysfunction, which can elevate PCT even in the absence of infection. Objective: To determine the optimal PCT threshold to identify infection in patients with renal dysfunction and pneumonia or sepsis. Methods: A retrospective analysis was performed for inpatients with creatinine clearance of ≤60 mL/min and PCT level from 2018 to 2019. A pharmacist blinded to study outcomes classified patients as infected or noninfected based on predetermined criteria. Receiver operating characteristic curve analysis was performed to establish the optimal PCT threshold overall, as well as in subgroups of patients with chronic kidney disease (CKD), acute kidney injury (AKI), and end-stage renal disease (ESRD). Institutional review board approval was obtained. Results: A total of 198 patients were included in the study (99 infected, 99 noninfected). The optimal threshold in the AKI, CKD, and ESRD subgroups was determined to be 1.5 ng/mL, 0.1 ng/mL, and 1.75 ng/mL, respectively. Conclusion: The results of this study show that PCT thresholds were specific to type of renal dysfunction. These results differ from the traditionally accepted PCT threshold of 0.5 ng/mL for sepsis and 0.25 mg/mL for pneumonia. Future studies should confirm the appropriate PCT threshold in ESRD and CKD patient populations.

Procalcitonin and Conventional Markers of Inflammation in Peritoneal Dialysis Patients and Peritonitis

Objectives

To determine the significance of a newly described marker of inflammation procalcitonin (PCT), and to investigate its relationship to conventional markers of inflammation, such as C-reactive protein (CRP), fibrinogen, and erythrocyte sedimentation rate (ESR), in patients on peritoneal dialysis (PD) and with peritonitis.

Design

A prospective, observational clinical study.

Setting

The Nephrology Division of a University-affiliated teaching hospital.

Patients and Methods

51 consecutive patients on PD were included in the study. Of this number, 16 developed peritonitis during the observational period. Baseline PCT, CRP, and fibrinogen concentrations and ESR of 51 PD patients were determined at a time point (TB) prior to any evidence of infection. These results were compared with laboratory values from 74 hemodialysis patients and 34 nonuremic control subjects. All PD patients then were followed prospectively for evidence of peritonitis. In addition to routine blood tests, including hemoglobin and leukocyte count, and routine biochemical tests, blood samples were taken to measure PCT, CRP, and fibrinogen concentrations and ESR at the time (T0) when patients first were diagnosed with PD peritonitis and also on the 4th (T4) and the 14th (T14) days after treatment for peritonitis was initiated. PCT was assayed by immunoluminometry.

Results

No significant difference was observed between baseline median serum PCT concentrations in PD and hemodialysis patients; however, in both groups, baseline median PCT concentrations were significantly higher than those of nonuremic controls ( p < 0.05). The 16 patients on PD who developed peritonitis had 21 PD peritonitis episodes during the study period. The increased PCT concentration observed at T0 in PD peritonitis episodes decreased with therapy, and this change was statistically significant ( p < 0.05). In a receiver operating characteristic curve analysis for peritonitis, the area under the curve (AUC) for PCT was 0.80, which was significantly lower than the AUC for CRP and greater than the AUCs for fibrinogen and ESR. The sensitivity of PCT for peritonitis was lower than the sensitivity of conventional markers of inflammation; however, the specificity of PCT was higher.

Conclusions

Median serum PCT concentration in PD patients was significantly higher than in nonuremic controls but not hemodialysis patients. Serum PCT concentrations may serve as a useful adjunct to traditional markers of inflammation in detecting and monitoring inflammation and peritonitis in PD patients.

Clinical Progress Note: Procalcitonin in the Diagnosis and Management of Community-Acquired Pneumonia in Hospitalized Adults

Community-acquired pneumonia (CAP) accounts for more than 1.5 million adult hospitalizations and 100,000 deaths each year in the United States.1 Antibiotic overuse in the hospital setting is an important contributor to the rise of antibiotic resistance, prompting increased efforts to limit inappropriate antibiotic use in hospitals.2 Procalcitonin, a precursor of the hormone calcitonin, is upregulated in bacterial infections and downregulated in viral infections. The US Food and Drug Administration has approved it as a serum biomarker to assist clinicians with decisions about using antibiotics.3 There is no consensus on how to best use procalcitonin in the management of CAP. We provide a practical update that includes a review of recent literature, added secondary analysis, and expert opinion surrounding the use of procalcitonin in the diagnosis and management of CAP in hospitalized adults.

The Confounding Effects of Non-cardiac Pathologies on the Interpretation of Cardiac Biomarkers

PURPOSE OF REVIEW

Cardiac biomarkers play important roles in routine evaluation of cardiac patients. But while these biomarkers can be extremely valuable, none of them should ever be used by themselves-without adding the clinical context. This paper explores the non-cardiac pathologies that can be seen with the cardiac biomarkers most commonly used.

RECENT FINDINGS

High-sensitivity troponin assay gained FDA approval for use in the USA, and studies demonstrated its diagnostic utility can be extended to patients with renal impairment. Gender-specific cut points may be utilized for high-sensitivity troponin assays. In the realm of the natriuretic peptides, studies demonstrated states of natriuretic peptide deficiency in obesity and in subjects of African-American race. Regardless, BNP and NT-proBNP both retained prognostic utilities across a variety of comorbid conditions. We are rapidly gaining clinical evidence with use of soluble ST2 and procalcitonin levels in management of cardiac disease states. In order to get the most utility from their measurement, one must be aware of non-cardiac pathologies that may affect the levels of biomarkers as although many of these are actually true values, they may not represent the disease we are trying to delineate. A few take-home points are as follows: 1. A biomarker value should never be used without clinical context 2. Serial sampling of biomarkers is often helpful 3. Panels of biomarkers may be valuable.

Clinical effects of hemoadsorption with CytoSorb® in patients with severe acute pancreatitis: A case series

Hemoadsorption using CytoSorb^® has recently gained attention as a new therapy aimed at modulating the inflammatory response syndrome in critically ill patients. The aim of our study was to assess the clinical effects of CytoSorb in patients with severe acute pancreatitis. We prospectively included 12 patients admitted to the intensive care unit for severe acute pancreatitis. After inclusion, continuous venovenous hemodiafiltration in conjunction with CytoSorb was applied. Clinical data, number of organ dysfunctions, paraclinical data, and vasopressor support were collected before and after the treatment. The use of CytoSorb was associated with a decrease in C-reactive protein from 242 (30, 300) to 180 (20, 252) mg/L (p = 0.04) and procalcitonin from 2.21 (0.01, 15.02) to 1.10 (0.01, 3.79) ng/mL (p = 0.02). The median vasopressor support was 0.1 (0, 0.9) mg/h at the beginning of the treatment and it was discontinued in all cases after the treatment. In conclusion, the use of CytoSorb in patients with severe acute pancreatitis was associated with improved hemodynamics and decreased inflammatory markers.

Biological variation of procalcitonin levels in hemodialysis patients

BACKGROUND

There is no obvious evidence regarding biological variation of procalcitonin (PCT) levels in hemodialysis (HD) patients without infections. The aim of this study was to determine the within- and between-person biological variation of PCT levels in HD patients without infections.

METHODS

A multicenter, prospective, cohort study enrolled 123 HD patients without any signs of infectious disease. Baseline PCT levels were determined pre- and post-HD, and then repeated pre-HD PCT measurements were performed at 2, 4, 8, 12, 16, 20, and 24 weeks after baseline blood-sampling, regardless of the presence or absence of infectious disease. Analytical variation (CVa), the within-person biological variation (CVi), between-person biological variation (CVb), individual index (II), and the reference change value (RCV) were calculated.

RESULTS

The mean age was 62.4 years, 76.4% were male, and 32.5% had diabetes. The mean duration of HD was 87 months. The median value for baseline pre-HD PCT was 0.23 ng/mL, which is much higher than the reference level for healthy individuals. PCT levels decreased of 46.6% after a single HD session. CVi was 24.9%, CVb was 54.2%, II was 0.46, and RCV was calculated as 96.4% with 99% probability.

CONCLUSIONS

The PCT level was significantly higher in stable HD patients without manifest bacterial infection. CVb was more variable than CVi in HD patients, which indicates that relative change is more important than absolute PCT levels for diagnosing bacterial infection, and doubling or more of the baseline PCT level may imply the presence of a bacterial infection in HD patients.

Procalcitonin Monitoring as a Guide for Antimicrobial Therapy: A Review of Current Literature

Effective antimicrobial stewardship practices are increasingly essential to best utilize the current arsenal of antimicrobials for the shortest necessary duration to minimize the development of antimicrobial resistance, secondary infections, and health care costs. Monitoring of serum procalcitonin (PCT) levels represents an effective antimicrobial stewardship strategy to differentiate bacterial infections from viral infections and noninfectious inflammatory conditions. Current literature illustrates the merits of PCT monitoring in reducing duration of antibiotic therapy without detrimental effects on mortality or infection relapses. However, the interpretation of PCT levels can be challenging, especially in light of comorbid disease states that can elevate PCT levels. This review sheds light on the utility of PCT monitoring, as well as providing insight into the practical interpretation of PCT levels. Much of the current literature surrounding PCT monitoring consists of use among patients with lower respiratory tract infections or in the critically ill. Overall, studies have demonstrated shorter antibiotic therapy durations when PCT monitoring is utilized. No studies to date have found increased rates of mortality or infection relapses, suggesting that PCT monitoring is not only effective, but also safe when used as a guide for antimicrobial therapy. Nonetheless, many conditions were shown to elevate PCT serum concentrations, even in the absence of bacterial infections, which can make interpretation of PCT concentrations challenging. Two common conditions that affect the accurate interpretation of PCT levels are renal dysfunction and congestive heart failure. Limited studies have been performed in these populations, but current available data propose the need for higher PCT thresholds in those with renal dysfunction or congestive heart failure and support utilizing PCT trends to monitor clinical improvement from bacterial infections. Evidence also suggests that PCT monitoring is cost-effective, as long as the test is ordered judiciously. In summary, PCT monitoring represents a promising antimicrobial stewardship strategy to limit exposure to unnecessary antimicrobial therapy.

Role of Procalcitonin in the Management of Infected Patients in the Intensive Care Unit

The combination of molecular pathogen diagnostics and the biomarker procalcitonin (PCT) are changing the use of antimicrobials in patients admitted to critical care units with severe community-acquired pneumonia, possible septic shock, or other clinical syndromes. An elevated serum PCT level is good supportive evidence of a bacterial pneumonia, whereas a low serum PCT level virtually eliminates an etiologic role for bacteria even if the culture for a potential bacterial pathogen is positive. Serum PCT levels can be increased in any shocklike state; a low PCT level eliminates invasive bacterial infection as an etiology in more than 90% of patients.

Pretransplant serum procalcitonin level for prediction of early post-transplant sepsis in living donor liver transplantation

AIM

Infection is a frequent cause of in-hospital mortality after liver transplantation (LT). Elimination of possible risks in the pretransplant period, early diagnosis of post-transplant sepsis, and prompt treatment with antimicrobial agents are important. The objectives of this study were to analyze the impact of early post-transplant sepsis on outcomes and to clarify the value of predictive factors for early post-transplant sepsis.

METHODS

The study included 136 patients who underwent initial living donor LT (LDLT) at our institute between April 2009 and December 2016. Sepsis was defined using the third international consensus criteria. The results of biochemical tests at the introduction of anesthesia before LDLT were collected for pretransplant evaluation.

RESULTS

Post-transplant sepsis was found in 37 patients (27.2%). More patients had a pre-transplant serum procalcitonin (PCT) level >0.5 ng/mL in the sepsis group than in the non-sepsis group (11 [29.7%] vs 10 [10.1%]; P = 0.007). The 1-year survival rate in the sepsis group was significantly lower than in the non-sepsis group (53.8% vs 87.2%; P < 0.001). Multivariate analysis identified pretransplant serum PCT >0.5 ng/mL (odds ratio, 3.8; 95% confidence interval, 1.3-10.9; P = 0.01) as the only independent risk factor for post-transplant sepsis.

CONCLUSIONS

Survival of patients with early post-transplant sepsis was poor and the incidence of sepsis was associated with the pretransplant serum PCT level. Re-evaluation of the general condition and rescheduling of LT should be considered in a patient with pretransplant serum PCT >0.5 ng/mL.

Relationship between acute kidney injury and serum procalcitonin (PCT) concentration in critically ill patients with influenza infection

INTRODUCTION

Serum procalcitonin (PCT) concentration could be increased in patients with renal dysfunction in the absence of bacterial infection.

OBJECTIVE

To determine the interactions among serum renal biomarkers of acute kidney injury (AKI) and serum PCT concentration, in patients admitted to the intensive care unit (ICU) due to lung influenza infection.

DESIGN

Secondary analysis of a prospective multicentre observational study.

SETTING

148 Spanish ICUs.

PATIENTS

ICU patients admitted with influenza infection without bacterial co-infection. Clinical, laboratory and hemodynamic variables were recorded. AKI was classified as AKI I or II based on creatinine (Cr) concentrations (≥1.60-2.50mg/dL and Cr≥2.51-3.99mg/dL, respectively). Patients with chronic renal disease, receiving renal replacement treatment or with Cr>4mg/dL were excluded. Spearman's correlation, simple and multiple linear regression analysis were performed.

INTERVENTIONS

None.

RESULTS

Out of 663 patients included in the study, 52 (8.2%) and 10 (1.6%) developed AKI I and II, respectively. Patients with AKI were significantly older, had more comorbid conditions and were more severally ill. PCT concentrations were higher in patients with AKI (2.62 [0.60-10.0]ng/mL vs. 0.40 [0.13-1.20]ng/mL, p=0.002). Weak correlations between Cr/PCT (rho=0.18) and Urea (U)/PCT (rho=0.19) were identified. Simple linear regression showed poor interaction between Cr/U and PCT concentrations (Cr R²=0.03 and U R²=0.018). Similar results were observed during multiple linear regression analysis (Cr R²=0.046 and U R²=0.013).

CONCLUSIONS

Although PCT concentrations were slightly higher in patients with AKI, high PCT concentrations are not explained by AKI and could be warning sign of a potential bacterial infection.

Do we need new trials of procalcitonin-guided antibiotic therapy?

Using biomarkers as a guide to tailor the duration of antibiotic treatment in respiratory infections is an attractive hypothesis assessed in several studies. Recent work aiming to summarize the evidence assessed the effect of a procalcitonin (PCT)-guided antibiotic treatment on outcomes in acute lower respiratory tract infections (LRTI), suggesting that significant reductions in antibiotic duration occur when using a PCT-guided algorithm. However, controversial evidence also suggested PCT-guided algorithms were associated with increased antibiotic duration and increased incidence of Clostridium difficile, without any impact on mortality, in real-world settings. So, although using PCT-guided antibiotic stewardship is promising, after more than a decade of randomized controlled trials on this topic the evidence in its favor is still less than compelling due to limitations in trial design, not taking into consideration fundamental aspects of PCT biology, and the absence of evidence-based antimicrobial duration in intervention and control groups. In this commentary we highlight some questions and limitations of primary PCT study data that might impact interpretation and clinical use of PCT at the bedside.

Clinical value of procalcitonin for suspected nosocomial bloodstream infection

BACKGROUND/AIMS

Procalcitonin (PCT) may prove to be a useful marker to exclude or predict bloodstream infection (BSI). However, the ability of PCT levels to differentiate BSI from non-BSI episodes has not been evaluated in nosocomial BSI.

METHODS

We retrospectively reviewed the medical records of patients ≥ 18 years of age with suspected BSI that developed more than 48 hours after admission.

RESULTS

Of the 785 included patients, 105 (13.4%) had BSI episodes and 680 (86.6%) had non-BSI episodes. The median serum PCT level was elevated in patients with BSI as compared with those without BSI (0.65 ng/mL vs. 0.22 ng/mL, p = 0.001). The optimal PCT cut-off value of BSI was 0.27 ng/mL, with a corresponding sensitivity of 74.6% (95% confidence interval [CI], 66.4% to 81.7%) and a specificity of 56.5% (95% CI, 52.7% to 60.2%). The area under curve of PCT (0.692) was significantly larger than that of C-reactive protein (CRP; 0.526) or white blood cell (WBC) count (0.518). However, at the optimal cut-off value, PCT failed to predict BSI in 28 of 105 cases (26.7%). The PCT level was significantly higher in patients with an eGFR < 60 mL/min/1.73 m² than in those with an eGFR ≥ 60 mL/min/1.73 m² (0.68 vs. 0.17, p = 0.01).

CONCLUSIONS

PCT was more useful for predicting nosocomial BSI than CRP or WBC count. However, the diagnostic accuracy of predicting BSI remains inadequate. Thus, PCT is not recommended as a single diagnostic tool to avoid taking blood cultures in the nosocomial setting.

Novel applications for serum procalcitonin testing in clinical practice

INTRODUCTION

Procalcitonin has emerged as a reliable marker of acute bacterial infection in hospitalized patients and the assay has recently been incorporated into several clinical algorithms to reduce antimicrobial overuse, but its use in patients with end-organ dysfunction is controversial. Areas covered: In this review, the authors examine what is known about procalcitonin testing in patients with organ dysfunction, including those with end-stage renal disease, congestive heart failure, chronic obstructive pulmonary disease, and cirrhosis, and explore how the assay is now being used in the management of non-infectious diseases. Expert commentary: Procalcitonin holds tremendous promise to identify a diverse set of medical conditions beyond those associated with acute bacterial infection, including post-surgical anastomotic leaks, acute kidney injury, and complications after intracerebral hemorrhage. The authors review recent studies examining procalcitonin in these areas and explore how the assay might be used to guide diagnosis and prognosis of non-infectious diseases in the near future.

Patterns of C-reactive protein ratio predicts outcomes in healthcare-associated pneumonia in critically ill patients with cancer

PURPOSE

Describe the patterns of C-reactive protein relative changes in response to antibiotic therapy in critically ill cancer patients with healthcare-associated pneumonia (HCAP) and its ability to predict outcome.

METHODS

Secondary analysis of a prospective cohort of critically ill cancer patients with HCAP. CRP was sampled every other day from D0 to D6 of antibiotic therapy. Patients were classified according to an individual pattern of CRP-ratio response: fast - CRP at D4 of therapy was <0.4 of D0 CRP; slow - a continuous but slow decrease of CRP; non - CRP remained ≥0.8 of D0 CRP; biphasic - initial CRP decrease to levels <0.8 of the D0 CRP followed by a secondary rise ≥0.8.

RESULTS

129 patients were included and septic shock was present in 74% and invasive mechanical ventilation was used in 73%. Intensive care unit (ICU) and hospital mortality rates were 47% and 64%, respectively. By D4, both CRP and CRP-ratio of survivors were significantly lower than in nonsurvivors (p<0.001 and p=0.004, respectively). Both time-dependent analysis of CRP-ratio of the four previously defined patterns (p<0.001) as ICU mortality were consistently different [fast 12.9%, slow 43.2%, biphasic 66.7% and non 71.8% (p<0.001)].

CONCLUSION

CRP-ratio was useful in the early prediction of poor outcomes in cancer patients with HCAP.

Biomarkers kinetics in the assessment of ventilator-associated pneumonia response to antibiotics - results from the BioVAP study

PURPOSE

Our aim was to evaluate the role of biomarker kinetics in the assessment of ventilator-associated pneumonia (VAP) response to antibiotics.

MATERIALS AND METHODS

We performed a prospective, multicenter, observational study to evaluate in 37 microbiologically documented VAP, the kinetics of C-reactive protein (CRP), procalcitonin (PCT), mid-region fragment of pro-adrenomedullin (MR-proADM). The kinetics of each variable, from day 1 to 6 of therapy, was assessed with a time dependent analysis comparing survivors and non-survivors.

RESULTS

During the study period kinetics of CRP as well as its relative changes, CRP-ratio, was significantly different between survivors and non-survivors (p=0.026 and p=0.005, respectively). On day 4 of antibiotic therapy, CRP of survivors was 47% of the initial value while it was 96% in non-survivors. The kinetics of other studied variables did not distinguish between survivors and non-survivors. In survivors the bacterial load also decreased markedly. Adequate initial antibiotic therapy was associated with lower mortality (p=0.025) and faster CRP decrease (p=0.029).

CONCLUSIONS

C-reactive protein kinetics can be used to identify VAP patients with poor outcome as soon as four days after the initiation of treatment. (Trial registration - NCT02078999; registered 3 August 2012).

Bloodstream infections in internal medicine

Bloodstream infections (BSI) carry a heavy burden of morbidity and mortality in modern internal medicine wards (IMW). These wards are often filled with elderly subjects with several risk factors for BSI, such as multiple comorbidities, polypharmacy, immunosuppression, and indwelling devices. Diagnosing BSI in such a setting might require a high degree of suspicion, since the clinical presentation could be affected by underlying conditions and concomitant medications, which might delay the administration of an appropriate antimicrobial therapy, an event strongly and unfavorably influencing survival. Furthermore, selecting the appropriate antimicrobial therapy to treat these patients is becoming an increasingly complex task in which all possible benefits and costs should be carefully analyzed from patient and public health perspectives. Only a specialized, continuous, and interdisciplinary approach could really improve the management of IMW patients in an era of increasing antimicrobial resistance and complexity of care.

Personalized treatment of severe pneumonia in cancer patients

Patients with cancer are at increased risk for sepsis as a consequence of immunosuppression. The hospital mortality remains elevated and it could be attributed to antibiotic failure because of the presence of multiresistant pathogens. Once the patient is critically ill, the use of the American Thoracic Society/Infectious Diseases Society of America classification does not seem very useful in the assessment of outcomes and the choice of antimicrobials. In critically ill patients, the characteristics of clinical response to antibiotics are usually inaccurate and occur late in the course of disease. So, the sequential evaluation of C-reactive protein-ratio is useful in the early identification of patients with antibiotic failure. To achieve safe and efficient antimicrobial therapy, we proposed an algorithm that may aid clinicians in their decision-making process.

Cutoff value of serum procalcitonin as a diagnostic biomarker of infection in end-stage renal disease patients

BACKGROUND/AIMS

Serum procalcitonin (PCT) levels are low in healthy individuals but are elevated in patients with a serious bacterial infection or sepsis. In this study, we examined the ability of serum PCT concentration to diagnose infections in end-stage renal disease (ESRD) patients, and sought to determine an appropriate threshold level.

METHODS

Serum PCT levels were measured in ESRD patients on antibiotic therapy for a suspected bacterial infection (ESRD infection [iESRD] group, n = 21), and compared with those of ESRD patients on hemodialysis with no sign of infection (ESRD control [cESRD] group, n = 20).

RESULTS

The mean serum PCT concentration of the iESRD group was significantly higher than in the cESRD group (2.95 ± 3.67 ng/mL vs. 0.50 ± 0.49 ng/mL, p = 0.006), but serum PCT concentrations did not correlate with severity of infection. The optimized threshold level derived for serum PCT was 0.75 ng/mL, rather than the currently used 0.5 ng/mL; this threshold demonstrated a sensitivity and specificity of 76.2% and 80.0% for infection and 100% and 60.6% for systemic inflammatory response syndrome, respectively, compared with the cutoff of 0.5 ng/mL.

CONCLUSIONS

This study suggests that serum PCT at a cutoff value of 0.75 ng/mL is an appropriate indicator of infection in ESRD patients.

Clinical relevance of procalcitonin and C-reactive protein as infection markers in renal impairment: a cross-sectional study

Introduction

Although the clinical application of procalcitonin (PCT) as an infection marker in patients with impaired renal function (estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m²) has been increasing recently, it is unclear whether PCT is more accurate than C-reactive protein (CRP). We investigated the clinical value of CRP and PCT based on renal function.

Methods

From November 2008 to July 2011, a total of 493 patients who simultaneously underwent CRP and PCT tests were enrolled. The area under the receiver operating characteristic (ROC) curve and characteristics of both markers were analyzed according to infection severity and renal function.

Results

In patients with impaired renal function, the area under the ROC curve was 0.876 for CRP and 0.876 for PCT. In patients with infection, CRP levels differed depending on whether the infection was localized, septic, or severely septic, whereas PCT levels were higher in patients with severe sepsis or septic shock. In patients without infection, CRP did not correlate with eGFR, while PCT was negatively correlated with eGFR.

Conclusion

This study demonstrates that CRP is accurate for predicting infection in patients with impaired renal function. The study suggests that in spite of its higher cost, PCT is not superior to CRP as an infection marker in terms of diagnostic value.

Community-acquired pneumonia: identification and evaluation of nonresponders

Community acquired pneumonia (CAP) is a relevant public health problem, constituting an important cause of morbidity and mortality. It accounts for a significant number of adult hospital admissions and a large number of those patients ultimately die, especially the population who needed mechanical ventilation or vasopressor support. Thus, early identification of CAP patients and its rapid and appropriate treatment are important features with impact on hospital resource consumption and overall mortality. Although CAP diagnosis may sometimes be straightforward, the diagnostic criteria commonly used are highly sensitive but largely unspecific. Biomarkers and microbiological documentation may be useful but have important limitations. Evaluation of clinical response is also critical especially to identify patients who fail to respond to initial treatment since these patients have a high risk of in-hospital death. However, the criteria of definition of non-response in CAP are largely empirical and frequently markedly diverse between different studies. In this review, we aim to identify criteria defining nonresponse in CAP and the pitfalls associated with this diagnosis. We also aim to overview the main causes of treatment failure especially in severe CAP and the possible strategies to identify and reassess non-responders trying to change the dismal prognosis associated with this condition.

Update on procalcitonin measurements

Procalcitonin (PCT) is used as a biomarker for the diagnosis of sepsis, severe sepsis and septic shock. At the same time, PCT has also been used to guide antibiotic therapy. This review outlines the main indications for PCT measurement and points out possible pitfalls. The classic indications for PCT measurement are: (i) confirmation or exclusion of diagnosis of sepsis, severe sepsis, or septic shock, (ii) severity assessment and follow up of systemic inflammation mainly induced by microbial infection, and (iii) individual, patient adapted guide of antibiotic therapy and focus treatment. Using serially monitored PCT levels, the duration and need of antibiotic therapy can be better adapted to the individual requirements of the patient. This individualized approach has been evaluated in various studies, and it is recommended to be a part of an antibiotic stewardship program.

Effect of introducing procalcitonin on antimicrobial therapy duration in patients with sepsis and/or pneumonia in the intensive care unit

BACKGROUND

Utilizing procalcitonin (PCT) levels to limit antimicrobial overuse would be beneficial from a humanistic and economic perspective.

OBJECTIVE

To assess whether introducing PCT at a teaching hospital reduced antimicrobial exposure in critically ill patients.

METHODS

Patients wereadmitted to the intensive care unit (ICU) for >72 hours with sepsis and/or pneumonia. PCT levels were drawn on admission to the ICU or with new suspected infection, with at least 1 PCT level being drawn at least 48 hours later. Patients were matched in a 1:1 fashion to historical patients on age, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, gender, and primary diagnosis. The primary outcome was duration of initial antimicrobial exposure defined as days from initiation of antimicrobial therapy to the intentional discontinuation of therapy by the physician. Secondary end points included length of stay, readmission to the hospital, and relapse of infection.

RESULTS

There were 50 patients in the PCT group and 50 patients in the historical group. The initial duration of antimicrobials was 10 (±4.9) days compared with 13.3 (±7.2), which was statistically significant (P = .0238). The duration of stay in the hospital (13.5 compared with 17.8 days; P = .0299), readmission to the hospital (9 compared with 17; P = .055), and relapse of infection (3 compared with 11; P = .02) were seen less in the PCT group compared with controls.

CONCLUSION

Introducing PCT levels resulted in a shorter duration of initial antimicrobial therapy and was not associated with adverse treatment outcomes.

Clinical value of procalcitonin for patients with suspected bloodstream infection

OBJECTIVES

Procalcitonin (PCT) might be a useful marker to exclude bacteremia or to predict the severity of bacteremia and its outcome. However, most previous studies of PCT were limited to particular patient populations. In addition, reports about PCT levels in patients with renal dysfunction have been conflicting. We investigated the predictive value of PCT in an unselected population with suspected bloodstream infections and also assessed the relationship between PCT and renal function.

METHODS

We retrospectively analyzed medical records of 1,331 patients (age ≥1 8 years) with suspected bloodstream infections who had concurrent biochemical data and blood culture results.

RESULTS

The PCT level was significantly elevated in patients with positive blood cultures, and it showed a significant relation with survival in patients with bacteremia. The optimal cutoff value of PCT for predicting a positive blood culture showed an increase as the estimated glomerular filtration rate declined.

CONCLUSION

PCT can be a useful marker to exclude bacteremia and also to predict severe bacteremia, but renal function should be taken into account.

Description and predictive factors of infection in patients with chronic kidney disease admitted to the critical care unit

OBJECTIVES

To describe the spectrum of infection and multidrug-resistant bacterial colonization, and to identify early predictors of infection in patients with chronic kidney disease (CKD) admitted to the critical care unit (CCU).

METHODS

A 7-month observational prospective single-centre study in a French university hospital.

RESULTS

791 patients were admitted to the CCU, 135 of whom (17%) had severe CKD. Among these, 41 (30%) were infected on admission. Infection was microbiologically documented in 32 patients (78%), of which 7 (22%) were related to Pseudomonas aeruginosa. There was no infection related to extended-spectrum β-lactamase-producing enterobacteriaceae despite a 12% carriage rate on admission. A temperature ≥37.6 °C and a leukocyte count >12.000/mm³ were specific but poorly sensitive of infection (91% and 80%, and 45% and 39%, respectively). Using the threshold of 0.85 ng/ml, procalcitonin was a strong independent predictor of infection on admission (OR 12.8, 95% CI 4.4-37.3). Age (≥60 years) and the cause of CKD were two other predictors.

CONCLUSIONS

Infection accounts for one-third of CCU admissions in CKD patients, with a high prevalence of P. aeruginosa. The usual diagnostic criteria are inaccurate for diagnosing infection in this population. A procalcitonin ≥0.85 ng/ml might be helpful for early identifying CKD patients with infection.

Biomarker-guided antibiotic therapy in adult critically ill patients: a critical review

Biomarkers of infection, namely C-reactive protein and procalcitonin (PCT), are potentially useful in the diagnosis of infection as well as in the assessment of its response to antibiotic therapy. C-reactive protein variations overtime appears to have a good performance for the diagnosis of infection. Procalcitonin shows a better correlation with clinical severity. In addition, to overcome the worldwide problem of antibiotic overuse as well as misuse, biomarker guidance of antibiotic stewardship represents a promising new approach. In several randomized, controlled trials, including adult critically ill patients, PCT guidance was repeatedly associated with a decrease in the duration of antibiotic therapy. However, these trials present several limitations, namely high rate of patients' exclusion, high rate of algorithm overruling, long duration of antibiotic therapy in the control group, disregard the effect of renal failure on PCT level, and above all a possible higher mortality and higher late organ failure in the PCT arm. In addition, some infections (e.g., endocarditis) as well as frequent nosocomial bacteria (e.g., Pseudomonas aeruginosa) are not suitable to be assessed by PCT algorithms. Therefore, the true value of PCT-guided algorithm of antibiotic stewardship in assisting the clinical decision-making process at the bedside remains uncertain. Future studies should take into account the issues identified in the present review.

Decisional procalcitonin thresholds are not adapted to elderly patients admitted to the emergency room

CONTEXT

Diagnosis of sepsis in elderly is challenging.

OBJECTIVES

We investigated whether procalcitonin concentrations in elderly differed from values for the general population.

METHODS

Procalcitonin measurement was assessed prospectively in 307 apyretic patients ≥75 years visiting the emergency department.

RESULTS

Median age was 86 years [IQR81-90] and 222 (72%) were female. Procalcitonin concentration was 0.057 µg/L [0.040-0.092]; 99th percentile was 0.661 µg/L. Patients with procalcitonin concentrations above decisional thresholds had lower glomerular filtration rate and higher C-reactive protein concentrations.

CONCLUSIONS

Baseline procalcitonin levels are increased in elderly. Elevated values are common and associated to low-grade inflammation and lower eGFR.

Use of procalcitonin in patients on chronic hemodialysis: procalcitonin is not related with increased serum calcitonin

Objectives. To investigate whether procalcitonin (PCT) could be useful for detecting bacterial infections in patients on hemodialysis (HD) and with increased calcitonin (CT). Methods. This prospective study included 42 males and 34 females on HD. The infection group consisted of 15 patients with proven bacterial infections; the other 61 patients were designated as the noninfection group. Serum C-reactive protein (CRP), interleukin (IL)-6, white blood cell (WBC) count, immature and total neutrophil (I/T) ratio, and CT were measured at the beginning of HD, and serum PCT levels at the beginning of HD and after HD. Results. The mean CT level in the both groups was apparently higher than that of nonchronic kidney disease. Significantly higher values between the infection and noninfection groups were seen for CRP, IL-6, WBC, I/T ratio, PCT, and CT. The PCT value of the area under the receiver operating characteristic curve was 0.921, which was significantly higher than the values for CRP (0.853; P < 0.01), IL-6 (0.739; P < 0.01), WBC (0.692; P < 0.01), and I/T ratio (0.584; P < 0.01). Conclusions. PCT was useful marker of bacterial infection in patients on HD and with increased CT. PCT levels should be determined before HD.

Procalcitonin-guided interventions against infections to increase early appropriate antibiotics and improve survival in the intensive care unit: a randomized trial

OBJECTIVE

For patients in intensive care units, sepsis is a common and potentially deadly complication and prompt initiation of appropriate antimicrobial therapy improves prognosis. The objective of this trial was to determine whether a strategy of antimicrobial spectrum escalation, guided by daily measurements of the biomarker procalcitonin, could reduce the time to appropriate therapy, thus improving survival.

DESIGN

Randomized controlled open-label trial.

SETTING

Nine multidisciplinary intensive care units across Denmark.

PATIENTS

A total of 1,200 critically ill patients were included after meeting the following eligibility requirements: expected intensive care unit stay of ≥ 24 hrs, nonpregnant, judged to not be harmed by blood sampling, bilirubin <40 mg/dL, and triglycerides <1000 mg/dL (not suspensive).

INTERVENTIONS

: Patients were randomized either to the "standard-of-care-only arm," receiving treatment according to the current international guidelines and blinded to procalcitonin levels, or to the "procalcitonin arm," in which current guidelines were supplemented with a drug-escalation algorithm and intensified diagnostics based on daily procalcitonin measurements.

MEASUREMENTS AND MAIN RESULTS

The primary end point was death from any cause at day 28; this occurred for 31.5% (190 of 604) patients in the procalcitonin arm and for 32.0% (191 of 596) patients in the standard-of-care-only arm (absolute risk reduction, 0.6%; 95% confidence interval [CI] -4.7% to 5.9%). Length of stay in the intensive care unit was increased by one day (p = .004) in the procalcitonin arm, the rate of mechanical ventilation per day in the intensive care unit increased 4.9% (95% CI, 3.0-6.7%), and the relative risk of days with estimated glomerular filtration rate <60 mL/min/1.73 m was 1.21 (95% CI, 1.15-1.27).

CONCLUSIONS

Procalcitonin-guided antimicrobial escalation in the intensive care unit did not improve survival and did lead to organ-related harm and prolonged admission to the intensive care unit. The procalcitonin strategy like the one used in this trial cannot be recommended.

Procalcitonin and C-reactive protein levels as diagnostic tools in febrile patients admitted to a General Internal Medicine ward

OBJECTIVE

We study the extent to which procalcitonin (Pro-CT) and/or C-reactive protein (CRP) may be helpful in the early triage of febrile patients admitted to a general internal medicine ward.

METHODS

This is a prospective, observational study on 62 admitted patients in whom a temperature >38°C had been observed the day before inclusion.

RESULTS

Neither Pro-CT nor CRP was able to discriminate infectious (or bacterial) diseases from the other etiologies as a group, with an area under the ROC curve of 0.63 (95% CI 0.47-0.79, p=0.15) for Pro-CT and 0.61, (95CI 0.44-0.78, p=0.23) for CRP. Sensitivity and specificity for Pro-CT varied between 0.59 and 0.67 for a cut-off point of 0.2 ng/mL and 0.03 and 1 for a cut-off point of 10.0 ng/mL. However, in subgroup analysis, Pro-CT was able to discriminate between infectious and inflammatory diseases (Welch two sample t-test t=2.39, df=44.3, p=0.021).