Validity of procalcitonin for the diagnosis of bacterial infection in elderly patients

Biomarkers for risk stratification and antibiotic stewardship in elderly patients

PURPOSE

Optimal treatment of infections in the elderly patients population is challenging because clinical symptoms and signs may be less specific potentially resulting in both, over- and undertreatment. Elderly patients also have a less pronounced immune response to infection, which may influence kinetics of biomarkers of infection.

METHODS

Within a group of experts, we critically reviewed the current literature regarding biomarkers for risk stratification and antibiotic stewardship in elderly patients with emphasis on procalcitonin (PCT).

RESULTS

The expert group agreed that there is strong evidence that the elderly patient population is particularly vulnerable for infections and due to ambiguity of clinical signs and parameters in the elderly, there is considerable risk for undertreatment. At the same time, however, this group of patients is particularly vulnerable for off-target effects from antibiotic treatment and limiting the use of antibiotics is therefore important. The use of infection markers including PCT to guide individual treatment decisions has thus particular appeal in geriatric patients. For the elderly, there is evidence that PCT is a valuable biomarker for assessing the risk of septic complications and adverse outcomes, and helpful for guiding individual decisions for or against antibiotic treatment. There is need for additional educational efforts regarding the concept of "biomarker-guided antibiotic stewardship" for health care providers caring for elderly patients.

CONCLUSION

Use of biomarkers, most notably PCT, has high potential to improve the antibiotic management of elderly patients with possible infection for improving both, undertreatment and overtreatment. Within this narrative review, we aim to provide evidence-based concepts for the safe and efficient use of PCT in elderly patients.

A Clinical Diagnostic Study: Fibulin-2 is a Novel Promising Biomarker for Predicting Infection

Introduction

Infection remains a major cause of morbidity and mortality in hospital. As uncontrolled early infection may develop into systemic infection and eventually progress to sepsis, it is important to address infection at an early stage. Furthermore, early detection and prompt diagnosis of infection are the basis of clinical intervention. However, as a result of the interference of complex aetiologies, including fever and trauma, problems regarding the sensitivity and specificity of current diagnostic indices remain, such as for C-reactive protein (CRP), procalcitonin (PCT), white blood cells (WBC), neutrophil ratio (NEU%), interleukin-6 (IL-6) and D-dimer. As a result, there is an urgent need to develop new biomarkers to diagnose infection.

Methods

From January to October 2021, consecutive patients in the emergency department (ED) were recruited to investigate the feasibility of fibulin-2 as a diagnostic indicator of early infection. Fibulin-2 concentrations in plasma were determined with enzyme-linked immunosorbent assay (ELISA). The performance of fibulin-2 for predicting infection was analysed by receiver operating characteristic (ROC) curves.

Results

We found that the plasma fibulin-2 level was elevated in patients with infection compared with those without infection. ROC curve analysis showed that the area under the curve (AUC) for fibulin-2 was 0.712. For all patients included, the diagnostic ability of fibulin-2 (AUC 0.712) performed as well as CRP (AUC 0.667) and PCT (AUC 0.632), and better than WBC (AUC 0.620), NEU% (AUC 0.619), IL-6 (AUC 0.561) and D-dimer (AUC 0.630). In patients with fever, fibulin-2 performed as well as PCT and better than the other biomarkers in infection diagnosis. In particular, fibulin-2 performed better than all these biomarkers in patients with trauma.

Conclusion

Fibulin-2 is a novel promising diagnostic biomarker for predicting infection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-022-00622-y.

Continuous elevation of procalcitonin in cirrhosis combined with hepatic carcinoma: a case report

BACKGROUND

Serum levels of procalcitonin (PCT) are considered a useful biomarker for the diagnosis of bacterial infection or inflammation. There are few reports of high PCT levels in end-stage liver disease regardless of bacterial infection. Here, we present a case of extremely high PCT levels (> 100 ng/mL) in a patient with severe cirrhosis combined with hepatic carcinoma.

CASE PRESENTATION

A 65-year-old man developed end-stage cirrhosis with hepatic carcinoma. Radiographic imaging showed a massive hepatocellular carcinoma with multiple loci lack of indications of resection. Hence, transcatheter hepatic arterial chemoembolization was performed three times over a period of 4 months. Before and after interventional therapies, the biochemistry laboratory results were only slightly abnormal except for persistently high PCT concentrations (> 100 ng/mL), irrespective of the evidence for bacterial infection or sepsis.

CONCLUSIONS

This case suggests that continuously high levels of PCT (> 100 ng/mL) may be present in advanced liver disease, particularly in complex situations such as decompensated cirrhosis and liver cancer, in the absence of severe infection or sepsis. This knowledge could expand the significance of PCT in liver disease.

Procalcitonin and Liver Disease: A Literature Review

Procalcitonin (PCT) is a widely used biomarker for the diagnosis of bacterial infections. It is produced by various organs and the liver is considered to be the most important site of production. Severe liver dysfunction has been shown to influence PCT levels. Patients with no sources of infection who have liver disease are observed to have increased serum levels of PCT, thereby reducing the diagnostic utility and value within this particular patient subset. Here, we have summarized the relationship between PCT and liver disease, including liver cirrhosis, liver failure, and liver transplantation.

Procalcitonin is not an independent predictor of 30-day mortality, albeit predicts pneumonia severity in patients with pneumonia acquired outside the hospital

Background

Procalcitonin (PCT) is a useful marker for pneumonia. However, its clinical usefulness in elderly patients has not been studied extensively. This study aimed to assess the relationship between PCT and prognosis and pneumonia severity in elderly patients with pneumonia acquired outside the hospital.

Methods

Data considered relevant to pneumonia severity and prognosis were retrospectively obtained from clinical charts of all patients with pneumonia who were admitted to our hospital from 2010 to 2017. The primary outcome was 30-day mortality in elderly patients (aged ≥75 years), and the relationship between PCT levels and pneumonia severity, as determined by the pneumonia severity index (PSI) was also examined.

Results

Data were collected from 667 patients, of which 436 were elderly patients. Multivariate and receiver operating characteristic curve analysis revealed that albumin, body mass index, and PSI class rather than PCT are important factors related to 30-day mortality in elderly patients. PCT was also not an independent prognostic factor in younger patients. PCT levels significantly differed by pneumonia severity (mild, moderate, and severe) in both younger (p < 0.001) and elderly (p < 0.0001) patients, with levels increasing as severity increased. In contrast, C-reactive protein (CRP) levels and white blood cell counts did not significantly differ by pneumonia severity in younger and elderly patients. A subgroup analysis focused on Streptococcus pneumoniae pneumonia revealed that PCT levels differed by severity in elderly patients (p = 0.03), with levels increasing as severity increased.

Conclusion

PCT was not an independent predictor of 30-day mortality in both of elderly and younger patients. PCT levels, but not CRP levels, significantly increased with increasing pneumonia severity in younger and elderly patients, although the degree of increase tended to be lower in elderly patients compared to younger patients for the same severity. PCT levels also significantly increased with increasing pneumonia severity in elderly patients with Streptococcus pneumoniae pneumonia.

Pancreatic stone protein and soluble CD25 for infection and sepsis in an emergency department

BACKGROUND

Infection is a common problem in emergency departments (EDs) and is associated with high mortality, morbidity and costs. Identifying infection in ED patients can be challenging. Biomarkers can facilitate its diagnosis, enabling an early management and improving outcomes. In the critical care setting, two emerging biomarkers, pancreatic stone protein (PSP) and soluble CD25 (sCD25), have demonstrated to be useful for diagnosis of sepsis. We aimed to assess the diagnostic value of these biomarkers, in comparison with procalcitonin (PCT), for infection and sepsis in an ED population with suspected infection.

MATERIALS AND METHODS

Through a prospective, observational study, we investigated the utility of serum PCT, PSP and sCD25 levels, measured on admission, for diagnosis of infection and sepsis, defined according to the recently updated for sepsis (Sepsis-3), in patients presenting to the ED for suspected infection. Diagnostic accuracy was evaluated by using receiver operating characteristic curves (ROC) analysis.

RESULTS

Of the 152 patients enrolled in this study, 129 had a final diagnosis of infection, including 82 with noncomplicated infection and 47 with sepsis. Median PCT, PSP and sCD25 levels were significantly higher in patients with infection and sepsis. The ROC curve analysis revealed a similar diagnostic accuracy for infection (ROC area under the curve (AUC) PCT: 0·904; sCD25: 0·869 and PSP: 0·839) and for sepsis (ROC AUC: PCT: 0·820; sCD25: 0·835 and PSP: 0·872).

CONCLUSIONS

Pancreatic stone protein and sCD25 perform well as infection and sepsis biomarkers, with a similar performance than PCT, in ED patients with suspected infection. Further larger studies investigating use of PSP and sCD25 are needed.

Neutrophil CD64 Index as a superior biomarker for early diagnosis of infection in febrile patients in the hematology department

Background:

In the hematology department, the availability of biomarkers for early detection of infection is difficult to obtain. The present study aimed to compare the diagnostic values of neutrophil CD64 Index, procalcitonin (PCT), interleukin-6 (IL-6) and C-reactive protein (CRP) and to determine whether the combined analysis of these biomarkers offer stronger predictive power in the diagnosis for the infection of febrile patients.

Methods:

Neutrophil CD64 Index, PCT, IL-6 and CRP levels were determined in 356 febrile patients in the hematology ward from May 2013 to May 2015. Sensitivity, specificity, positive and negative likelihood ratios, positive and negative predictive values, receiver operating characteristic (ROC) areas under the curve (AUC), and logistic regression analysis were determined to evaluate the diagnostic values of these biomarkers.

Results:

The levels of the four biomarkers were higher in the infection patients (p<0.001), and the PCT and IL-6 were higher in the patients with positive microbial blood culture (p<0.01). The neutrophil CD64 Index, PCT, IL-6, CRP had AUCs of 0.95, 0.83, 0.75 and 0.73, respectively. The best cut-off value of the neutrophil CD64 Index to detect infections was 5.06, with high specificity (87.5%) and sensitivity (88.4%). Furthermore, neutrophil CD64 Index, PCT and IL-6 offered the best combination of diagnosis with sensitivity of 93.9% and an AUC of 0.95. In addition, the neutrophil CD64 Index may have a special value to assist the physician to diagnose infection in the neutropenic patients with fever.

Conclusions:

The neutrophil CD64 Index is useful for early identification of infections in febrile patients in the hematology department. The combined analysis of the CD64 Index, PCT and IL-6 could further improve its sensitivity.