Influence of procalcitonin on decision to start antibiotic treatment in patients with a lower respiratory tract infection: insight from the observational multicentric ProREAL surveillance

Diagnosis of bacterial infection in children with relapse of nephrotic syndrome: a personalized decision-analytic nomogram and decision curve analysis

BACKGROUND

Infections associated with nephrotic relapses (NR) are often managed according to physician preferences. A validated prediction tool will aid clinical decision-making and help in rationalizing antibiotic prescriptions. Our objective was to develop a biomarker-based prediction model and a regression nomogram for the prediction of the probability of infection in children with NR. We also aimed to perform a decision curve analysis (DCA).

METHODS

This cross-sectional study included children (1-18 years) with NR. The outcome of interest was the presence of bacterial infection as diagnosed using standard clinical definitions. Total leucocyte count (TLC), absolute neutrophil count (ANC), quantitative C-reactive protein (qCRP), and procalcitonin (PCT) were the biomarker predictors. Logistic regression was used to identify the best biomarker model, followed by discrimination and calibration testing. Subsequently, a probability nomogram was constructed and DCA was done to determine the clinical utility and net benefits.

RESULTS

We included 150 relapse episodes. A bacterial infection was diagnosed in 35%. Multivariate analysis showed the ANC + qCRP model to be the best predictive model. This model displayed excellent discrimination (AUC: 0.83), and calibration (optimism-adjusted intercept: 0.015, slope: 0.926). A prediction nomogram and web-application was developed. The superiority of the model was also confirmed by DCA in the probability threshold range of 15-60%.

CONCLUSIONS

An ANC-based and qCRP-based internally validated nomogram can be used for the prediction of probability of infection in non-critically ill children with NR. Decision curves from this study will aid in the decision-making of empirical antibiotic therapy, incorporating threshold probabilities as a surrogate of physician preference. A higher resolution version of the Graphical abstract is available as Supplementary information.

Procalcitonin and C-Reactive Protein/Procalcitonin Ratio as Markers of Infection in Patients With Solid Tumors

Objectives: The roles of procalcitonin (PCT) and C-reactive protein (CRP) in febrile cancer patients is currently unclear. Our aim was to assess these in febrile patients with solid tumors and to identify cut-off values for ruling out infection.

Methods: We retrospectively evaluated patients with solid tumors admitted to hospital due to fever. They were divided into those with Fever with microbiologically documented infection (FMDI), Fever with clinically documented infection (FCDI) and Tumor-related fever (TRF). PCT and CRP levels were compared. Receiver-operating curves were plotted to define the best cut-off values for discriminating between infection-related and cancer-related fever.

Results: Between January 2015 to November 2018, 131 patients were recorded (mean age 68 years, 67% male, 86% with metastasis). Patients with FMDI or FCDI had significantly higher baseline levels of PCT and lower CRP/PCT than those with TRF. A PCT cut-off value of 0.52 ng/mL for discriminating between infection and cancer-associated fever yielded 75% sensitivity, 55% specificity, 77% positive predictive value (PPV), and 52% negative predictive value (NPV). A CRP/PCT ratio with a cut-off value of 95 showed 56% sensitivity, 70% specificity, 79% NPV, and 44% PPV.

Discussion: PCT is a sensitive marker of sepsis or localized infection in patients with solid tumors, but its specificity is poor. The CRP/PCT ratio improves specificity, thus providing a reliable means of ruling out infection for values above 95.

Quantum Dots-Based Point-of-Care Measurement of Procalcitonin in Finger-Prick Blood and Venous Whole Blood Specimens

OBJECTIVE

To determine whether the performance of a new quantum dots-based point-of-care test (POCT) devices is qualified for procalcitonin testing.

METHODS

Finger-prick and venous blood specimens from 153 patients were measured with a quantum dots-based POCT device; the results were compared with those from the reference method.

RESULTS

The quantum dots-based POCT device correlated well with the reference method in measuring plasma, venous whole blood, and finger-prick blood. No significant bias was observed (-0.08 ng/mL). At 0.5 ng per mL cutoff value, the concordances were 96.6%, 94.6%, and 90.5% for plasma, venous whole blood, and finger-prick blood, respectively. And at 2 ng per mL cutoff value, the concordances were 98.0%, 96.6%, and 95.3%, respectively.

CONCLUSIONS

The quantum dots-based POCT device measured procalcitonin with multiple specimen types, high sensitivity, wide detection range, and short turnaround time. It would allow a more widespread use of procalcitonin and help lessen the burden of overcrowding in healthcare facilities in China.

Adhering to the procalcitonin algorithm allows antibiotic therapy to be shortened in patients with ventilator-associated pneumonia

PURPOSE

Ventilator-associated pneumonia (VAP) increases exposure to antibiotics. Physicians are however reluctant to shorten treatment, arguing this could lead to failures and worse outcome. Monitoring procalcitonin (PCT) has proven effective for decreasing exposure to antibiotics in randomized controlled trials, but additional "real-life" studies are needed.

MATERIALS AND METHODS

All patients with VAP in whom ABT was stopped before death or discharge were included in this 5-year prospective cohort study. Patients in whom ABT was stopped in accordance with the algorithm ("PCT-guided" group: ABT withdrawal strongly encouraged if PCT < 0.5 ng/mL or < 80% peak value) were compared to those with ABT continuation despite PCT decrease ("not PCT-guided" group). The primary endpoint was ABT duration. The secondary endpoint was unfavorable VAP outcome (i.e. death or relapse).

RESULTS

We included 157 of the 316 patients with microbiologically-proven VAP. The algorithm was overruled in 81 patients (51.6%). ABT duration was significantly longer in these patients than in the PCT-guided group (9.5 vs. 8.0 days; p = .02), although baseline and VAP characteristics did not differ. The rate of unfavorable outcomes was comparable (46.9% vs. 51.3%; p = .69).

CONCLUSIONS

PCT-guided ABT adherence appears safe for patients with VAP and is likely to reduce exposure to antibiotics.

Comparison of the novel ARCHITECT procalcitonin assay with established procalcitonin assay systems

AIMS

This study assessed the performance of a new fully automated immunoassay, ARCHITECT B.R.A.H.M.S procalcitonin (PCT), comparing the results with other commercial assays on routine clinical specimens.

METHODS

At nine sites from eight countries, precision analysis was carried out on controls by ANOVA. Threshold and linearity were verified according to standard procedures. Comparison of ARCHITECT B.R.A.H.M.S PCT with the Cobas®, LIAISON®, VIDAS® and Kryptor® PCT assays was evaluated using Passing-Bablok and Deming regression analyses.

RESULTS

The within-laboratory standard deviation and %CV across all sites ranged from 0.005 to 0.008 and 2.7 to 4.1; 0.040 to 0.212 and 2.1 to 11.7; 1.628 to 4.191 and 2.5-6.3 for the three control levels, respectively. The mean slope (linearity analysis) across all sites ranged from 0.85 to 1.03, with a mean y-intercept ranging from -6.15 to + 1.71 and a correlation coefficient ranging from 0.94 to 1.00. The LoB, LoD, and LoQ claims were verified. Deming regression analysis of 1116 plasma or serum samples with PCT results detected across a dynamic assay range of 0.02-100 μg/l using the ARCHITECT B.R.A.H.M.S PCT assay yielded results of r = 0.989 vs. Roche Cobas®, r = 0.986 vs Kryptor® B.R.A.H.M.S, r = 0.987 vs BioMèrieux VIDAS® and r = 0.972 vs. Diasorin LIAISON®, respectively. Concordance at cut-offs of 0.25 μg/l and 0.50 μg/l were 96.9% and 98.1% with Roche Cobas®, 95.4% and 96.1% with B.R.A.H.M.S Kryptor®, 93.8% and 98.4% with BioMèrieux VIDAS®, and 92.7% and 93.9% with Diasorin LIAISON®.

CONCLUSIONS

Compared with other assays, ARCHITECT B.R.A.H.M.S PCT offers excellent precision and low-end sensitivity.

Procalcitonin as Biomarker of Infection: Implications for Evaluation and Treatment

Procalcitonin (PCT) is a quickly measurable marker, assumed to have high sensitivity and specificity for sepsis and infection. A literature search was conducted to evaluate PCT ability as a diagnostic and prognostic tool in infectious processes and its ability to monitor the antibiotic therapy. PCT level is increased in bacterial and fungal infections, but not in viral infections, with a significantly higher level in patients with bacteremia compared with uninfected patients (2.5 vs. 0.3 ng/mL; P < 0.0001). A PCT value of ≤0.1 ng/mL discards bacteremia and microbiological tests (negative predictive value of 96.3%), >0.1 ng/mL needs microbiological tests, and >1.0 ng/mL is indicative of bacteremia. Antibiotic treatment algorithms guided by PCT decreased the need for antibiotic treatment in approximately 50%. PCT is a promising test in clinical practice to decide the introduction of antibiotic therapy in addition to the existing tools, without neglecting the clinical assessment, with a significant decrease in costs.

Procalcitonin-guided diagnosis and antibiotic stewardship revisited

Several controlled clinical studies have evaluated the potential of the infection biomarker procalcitonin (PCT) to improve the diagnostic work-up of patients with bacterial infections and its influence on decisions regarding antibiotic therapy. Most research has focused on lower respiratory tract infections and critically ill sepsis patients. A clinical utility for PCT has also been found for patients with urinary tract infections, postoperative infections, meningitis, and patients with acute heart failure with possible superinfection (i.e., pneumonia). In these indications, PCT levels measured on hospital admission were found to substantially reduce the initiation of antibiotic treatment in low-risk situations (i.e., bronchitis, chronic obstructive pulmonary disease exacerbation). For more severe infections (i.e., pneumonia, sepsis), antibiotic stewardship by monitoring of PCT kinetics resulted in shorter antibiotic treatment durations with early cessation of therapy. Importantly, these strategies appear to be safe without increasing the risk for mortality, recurrent infections, or treatment failures. PCT kinetics also proved to have prognostic value correlating with disease severity (i.e., pancreatitis, abdominal infection) and resolution of illness (i.e., sepsis). Although promising findings have been published in these different types of infections, there are a number of limitations regarding PCT, including suboptimal sensitivity and/or specificity, which makes a careful interpretation of PCT in the clinical context mandatory. This narrative review aims to update clinicians on the strengths and limitations of PCT for patient management, focusing on research conducted within the last 4 years.

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

Background:

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

Methods:

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

Results:

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

Conclusions:

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

Provider Decisions to Treat Respiratory Illnesses with Antibiotics: Insights from a Randomized Controlled Trial

RATIONALE

Lower respiratory tract illness (LRTI) frequently causes adult hospitalization and antibiotic overuse. Procalcitonin (PCT) treatment algorithms have been used successfully in Europe to safely reduce antibiotic use for LRTI but have not been adopted in the United States. We recently performed a feasibility study for a randomized clinical trial (RCT) of PCT and viral testing to guide therapy for non-pneumonic LRTI.

OBJECTIVE

The primary objective of the current study was to understand factors influencing PCT algorithm adherence during the RCT and evaluate factors influencing provider antibiotic prescribing practices for LRTI.

STUDY DESIGN

From October 2013-April 2014, 300 patients hospitalized at a community teaching hospital with non-pneumonic LRTI were randomized to standard or PCT-guided care with viral PCR testing. Algorithm adherence data was collected and multivariate stepwise logistic regression of clinical variables used to model algorithm compliance. 134 providers were surveyed anonymously before and after the trial to assess knowledge of biomarkers and viral testing and antibiotic prescribing practices.

RESULTS

Diagnosis of pneumonia on admission was the only variable significantly associated with non-adherence [7% (adherence) vs. 26% (nonadherence), p = 0.01]. Surveys confirmed possible infiltrate on chest radiograph as important for provider decisions, as were severity of illness, positive sputum culture, abnormal CBC and fever. However, age, patient expectations and medical-legal concerns were also at least somewhat important to prescribing practices. Physician agreement with the importance of viral and PCT testing increased from 42% to 64% (p = 0.007) and 49% to 74% (p = 0.001), respectively, after the study.

CONCLUSIONS

Optimal algorithm adherence will be important for definitive PCT intervention trials in the US to determine if PCT guided algorithms result in better outcomes than reliance on traditional clinical variables. Factors influencing treatment decisions such as patient age, presence of fever, patient expectations and medical legal concerns may be amenable to education to improve PCT algorithm compliance for LRTI.

Serum Procalcitonin Measurement and Viral Testing to Guide Antibiotic Use for Respiratory Infections in Hospitalized Adults: A Randomized Controlled Trial

Background. Viral lower respiratory tract illness (LRTI) frequently causes adult hospitalization and is linked to antibiotic overuse. European studies suggest that the serum procalcitonin (PCT) level may be used to guide antibiotic therapy. We conducted a trial assessing the feasibility of using PCT algorithms with viral testing to guide antibiotic use in a US hospital.

Methods. Three hundred patients hospitalized with nonpneumonic LRTI during October 2013–April 2014 were randomly assigned at a ratio of 1:1 to receive standard care or PCT-guided care and viral PCR testing. The primary outcome was antibiotic exposure, and safety was assessed at 1 and 3 months.

Results. Among the 151 patients in the intervention group, viruses were identified in 42% (63), and 83% (126) had PCT values of <0.25 µg/mL. There were no significant differences in antibiotic use or adverse events between intervention patients and those in the nonintervention group. Subgroup analyses revealed fewer subjects with positive results of viral testing and low PCT values who were discharged receiving antibiotics (20% vs 45%; P = .002) and shorter antibiotic durations among algorithm-adherent intervention patients versus nonintervention patients (2.0 vs 4.0 days; P = .004). Compared with historical controls (from 2008–2011), antibiotic duration in nonintervention patients decreased by 2 days (6.0 vs 4.0 days; P < .001), suggesting a study effect.

Conclusions. Although antibiotic use was similar in the 2 arms, subgroup analyses of intervention patients suggest that physicians responded to viral and biomarker data. These data can inform the design of future US studies.

Clinical Trials Registration. NCT01907659.

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.

[Severe infections : causes and management of sepsis]

The sepsis syndrome has only recently been defined as a clinical syndrome but despite its unspecific definition it has evolved rapidly into an important concept. Although specific therapeutic interventions targeting the inflammatory pathway have not yet been effective in treating sepsis, a better understanding of mechanisms leading to organ dysfunction has led to better management of patients with sepsis. Clinical signs of systemic inflammatory response syndrome (SIRS) or sepsis are hallmarks for the definition of severe infections. Current guidelines are presented for the management of a number of severe infectious syndromes.