Utility of serum procalcitonin values in patients with acute exacerbations of chronic obstructive pulmonary disease: a cautionary note

Biomarkers to guide the use of antibiotics for acute exacerbations of COPD (AECOPD): a systematic review and meta-analysis

Background

Antibiotics are frequently prescribed for acute exacerbations of COPD (AECOPD) even though most do not have a bacterial aetiology. Biomarkers may help clinicians target antibiotic use by identifying AECOPD caused by bacterial pathogens. We aimed to summarise current evidence on the diagnostic accuracy of biomarkers for detecting bacterial versus non-bacterial AECOPD.

Methods

We searched Embase and Medline using a search strategy including terms for COPD, biomarkers and bacterial infection. Data regarding diagnostic accuracy for each biomarker in predicting bacterial cause of exacerbation were extracted and summarised. We used to QUADAS-2 tool to assess risk of bias.

Results

Of 509 papers identified, 39 papers evaluating 61 biomarkers were eligible for inclusion. Moderate quality evidence was found for associations between serum C-reactive protein (CRP), serum procalcitonin (PCT), sputum interleukin (IL)-8 and sputum tumour necrosis factor alpha (TNF-α), and the presence of bacterial pathogens in the sputum of patients with AECOPD. Having bacterial pathogens was associated with a mean difference (higher) CRP and PCT of 29.44 mg/L and 0.76 ng/mL respectively. There was inconsistent or weak evidence for associations between bacterial AECOPD and higher levels of sputum IL-1β, IL-6, myeloperoxidase (MPO) and neutrophil elastase (NE). We did not find any consistent evidence of diagnostic value for other biomarkers.

Conclusions

There is moderate evidence from heterogeneous studies that serum CRP and PCT are of value in differentiating bacterial from non-bacterial AECOPD, and little evidence for other biomarkers. Further high-quality research on the role of biomarkers in identifying bacterial exacerbations is needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01958-4.

Optimal cut-off value of serum procalcitonin in predicting bacterial infection induced acute exacerbation in chronic obstructive pulmonary disease: A prospective observational study

Objective

To explore the optimal cut-off value of serum procalcitonin (PCT) level in predicting bacterial infection in hospitalized patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Methods

204 hospitalized patients with AECOPD were enrolled in this study. Their diagnoses and treatments followed routine protocols in Fu-Xing Hospital affiliated to Capital Medical University, Beijing, China. Extra blood samples were taken for serum PCT level testing and the results were blinded to the treating physicians. On discharge, clinical data were collected and the treating physicians made comprehensive analyses to determine whether the AECOPD were triggered by respiratory tract bacterial infection or non-bacterial causes according to the “new diagnostic criteria” defined in this study. In the AECOPD patients with bacterial infection, treating physicians decided whether they had bacterial pneumonia based on imaging studies. Receiver operating characteristic curve (ROC) was used to analyze the accuracy of serum PCT level in predicting bacterial infection.

Results

In the 173 AECOPD patients who did not have pneumonia, 115 had evidences of bacterial infection while 58 did not. The median PCT levels were 0.1(0.08, 0.18) ng/ml and 0.07 (0.05, 0.08) ng/ml for each group, which were statistically different. The proposed optimal cut-off value of serum PCT level in predicting bacterial infection was 0.08 ng/mL according to this study, with a sensitivity of 81%, specificity of 67% and area under the ROC curve (AUC) of 0.794. There were 31 AECOPD patients diagnosed with pneumonia, their median PCT level was 0.23 ng/mL.

Conclusions

The serum PCT levels slightly increased in the majority of hospitalized patients with AECOPD compared with reference range. When PCT level was ≥0.08 ng/mL, AECOPD was more likely to be caused by bacterial infection. A significantly elevated PCT levels may indicate combination of AECOPD and bacterial pneumonia.

Inflammatory Biomarkers Are Inaccurate Indicators of Bacterial Infection on Admission in Patients With Acute Exacerbation of Chronic Obstructive Pulmonary Disease-A Systematic Review and Diagnostic Accuracy Network Meta-Analysis

Introduction: The value of inflammatory biomarkers in the diagnosis of bacterial infection induced acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is currently unclear. Our objective was to investigate the diagnostic accuracy of on-admission inflammatory biomarkers in differentiating bacterial origin in AECOPD.

Methods: Systematic literature search was performed to include cross-sectional studies on AECOPD patients with microbiological culture results as gold standard, and at least one on-admission inflammatory biomarker determined from serum: C-reactive protein (CRP), procalcitonin (PCT), neutrophil/lymphocyte ratio, eosinophil percentage, CD64index; or sputum: neutrophil elastase, tumor necrosis factor alfa, interleukin-1-beta (IL-1b), interleukin-8, sputum color, as index tests. We ranked index tests by superiority indices in a network meta-analysis and also calculated pooled sensitivity and specificity.

Results: Altogether, 21 eligible articles reported data on 2,608 AECOPD patients (44% bacterial). Out of the 14 index tests, sputum IL-1b showed the highest diagnostic performance with a pooled sensitivity of 74% (CI: 26–97%) and specificity of 65% (CI: 19–93%). Pooled sensitivity for CRP and PCT were: 67% (CI: 54–77%) and 54% (CI: 39–69%); specificity 62% (CI: 52–71%) and 71% (CI: 59–79%), respectively.

Conclusion: Admission inflammatory biomarkers are inaccurate indicators of bacterial infection in AECOPD.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/#myprospero, identifier: 42020161301.

Usefulness of serum procalcitonin for necrotizing fasciitis as an early diagnostic tool

INTRODUCTION

While the early diagnosis of necrotizing fasciitis (NF) is crucial and could lead to a favorable outcome, it is difficult to differentiate NF from cellulitis, resulting in delay for the appropriate treatment.

PATIENTS AND METHODS

For the purpose of examining which diagnostic tools could correctly differentiate NF from cellulitis, we conducted this case-control study. We retrospectively reviewed all patients who were diagnosed with NF at our institute during 2014-2019. The patients who were diagnosed with cellulitis were randomly selected during the study period as the control group. The severity of NF is evaluated by serum-procalcitonin (PCT), LRINEC score, NTSI assessment and SIARI score.

RESULTS

A total of 25 NF patients were enrolled in this study. The median age was 68 years (range 39-79) and 18 (72%) were male. Comparing NF and cellulitis groups, NF group showed a higher LRINEC score and serum PCT than cellulitis group did, even though there was no statistical significance in serum PCT. With respect to the diagnostic value for differentiating NF from cellulitis, the area under the ROC curve for of serum PCT and LRINEC scores were 0.928 [95% confidential interval (CI) 0.864-0.992, p < 0.001] and 0.846 (95% CI 0.757-0.936, p < 0.001). The appropriate serum-PCT cutoff value was 1.0 and had a sensitivity of 88%, a specificity of 89%, a positive predictive value of 81%, and a negative predictive value of 93%.

CONCLUSION

Serum-PCT could be a useful diagnostic marker for differentiating diagnosis of NF from cellulitis.

Procalcitonin for Antibiotic Prescription in Chronic Obstructive Pulmonary Disease Exacerbations: Systematic Review, Meta-Analysis, and Clinical Perspective

The 2020 Global Initiative for Obstructive Lung Disease report indicates that the blood biomarker procalcitonin (PCT) may assist in decision-making regarding the initiation of antibiotics for chronic obstructive pulmonary disease (COPD) exacerbations. PCT is an acute-phase reactant that increases in response to inflammation and infection, and has been studied in various bacterial infections for initiation and de-escalation of antibacterials. The purpose of this systematic review and meta-analysis was to evaluate the strength of the data on the use of PCT to guide antibiotic prescription in COPD exacerbations. Among the randomized clinical trials included in our meta-analysis, almost all of which were conducted exclusively in the hospital setting. PCT was found to decrease overall antibiotic exposure in COPD exacerbations by 2.01 days (p = 0.04), while no apparent effects were found on clinical outcomes (length of hospital stay, p = 0.88; treatment failure p = 0.51; all-cause mortality p = 0.28). However, the majority of blood PCT levels in COPD exacerbations were below the manufacturer-recommended cutoff for antibiotics, and the use of this marker was associated with worse outcomes in the intensive care setting. Further, based on additional sensitivity analysis excluding studies with high risk of bias or with converted outcome value, the effect of PCT on antibiotic duration in RCTs was no longer significant (MD = -1.88 days, 95% CI [-3.95, 0.19] days, p = 0.08, and MD = -1.72 days, 95% CI [-4.28, 0.83] days, p = 0.19, respectively). Our review and analysis does not support the use of PCT to guide antibiotic prescription in COPD exacerbations.

Serum Procalcitonin Levels on Admission Predict Death in Severe and Critical COVID-19 Patients in Wuhan, China

Background: We evaluated whether the serum procalcitonin (PCT) level could predict death in severe and critical coronavirus disease 2019 (COVID-19) patients.Methods: This study included 129 COVID-19 patients. PCT levels on admission, treatment, and death were collected. The outcomes were compared.Results: The optimum cutoff value of the PCT level determined by receiver operator characteristic curve analysis to predict all-cause death was 0.085 ng/mL, with sensitivity of 95.7% and specificity of 72.6%. Overall, 78 patients had a PCT level below 0.085 ng/mL and 51 patients had a PCT level of 0.085 ng/mL or greater. High-PCT-level patients had lower levels of lymphocytes (P=0.001) and albumin (P=0.002) and higher levels of creatinine (P=0.024), D-dimer (P=0.002), and white blood cells, neutrocytes (P<0.001), high-sensitivity C-reactive protein (P<0.001), interleukin-6 (P<0.001), interleukin-8 (P=0.001), interleukin-10 (P=0.001), tumor necrosis factor (P<0.001), erythrocyte sedimentation rate (P=0.001), and ferritin (P=0.001). During the 30-day observation period, 23 patients died. Mortality was significantly higher in high-PCT-level patients than in patients with low PCT levels (43.1% vs. 1.3%; P<0.001). The risks of death (P<0.0001) and ventilator use (P<0.0001) were increased in patients with PCT levels of 0.085 ng/mL or greater.Conclusions: A PCT level of 0.085 ng/mL or greater on admission could effectively predict death and ventilator use in severe and critical COVID-19 patients.

Pneumonic versus Nonpneumonic Exacerbations of Chronic Obstructive Pulmonary Disease

Patients with chronic obstructive pulmonary disease (COPD) often suffer acute exacerbations (AECOPD) and community-acquired pneumonia (CAP), named nonpneumonic and pneumonic exacerbations of COPD, respectively. Abnormal host defense mechanisms may play a role in the specificity of the systemic inflammatory response. Given the association of this aspect to some biomarkers at admission (e.g., C-reactive protein), it can be used to help to discriminate AECOPD and CAP, especially in cases with doubtful infiltrates and advanced lung impairment. Fever, sputum purulence, chills, and pleuritic pain are typical clinical features of CAP in a patient with COPD, whereas isolated dyspnea at admission has been reported to predict AECOPD. Although CAP may have a worse outcome in terms of mortality (in hospital and short term), length of hospitalization, and early readmission rates, this has only been confirmed in a few prospective studies. There is a lack of methodologically sound research confirming the impact of severe AECOPD and COPD + CAP. Here, we review studies reporting head-to-head comparisons between AECOPD and CAP + COPD in hospitalized patients. We focus on the epidemiology, risk factors, systemic inflammatory response, clinical and microbiological characteristics, outcomes, and treatment approaches. Finally, we briefly discuss some proposals on how we should orient research in the future.

A 2020 review on the role of procalcitonin in different clinical settings: an update conducted with the tools of the Evidence Based Laboratory Medicine

Biomarkers to guide antibiotic treatment decisions have been proposed as an effective way to enhancing a more appropriate use of antibiotics. As a biomarker, procalcitonin (PCT) has been found to have good specificity to distinguish bacterial from non-bacterial inflammations. Decisions regarding antibiotic use in an individual patient are complex and should be based on the pre-test probability for bacterial infection, the severity of presentation and the results of PCT serum concentration. In the context of a high pre-test probability for bacterial infections and/or a high-risk patient with sepsis, monitoring of PCT over time helps to track the resolution of infection and decisions regarding early stop of antibiotic treatment. As outlined by the Evidence Based Laboratory Medicine (EBLM), not only the pre-test probability but also the positive likelihood ratio influence the performance of a test do be really diagnostic. This aspect should be taken into account in the interpretation of the results of clinical trials evaluating the performance of PCT in guiding antibiotic therapy.

Serum procalcitonin levels in chronic obstructive pulmonary disease patients in North Indian Population

Background

Exacerbations in Chronic obstructive pulmonary disease (COPD) have a considerable impact on morbidity, mortality, and quality of life. Procalcitonin (PCT) a polypeptide normally produced in neuroendocrine cells of the thyroid and lungs is a marker of systemic inflammation and bacterial infection.

Objectives

The aim of this study was to determine the levels of PCT in serum of acute exacerbation of COPD patients (AECOPD) and stable COPD patients in North Indian population.

Materials and Methods

The study was conducted on 80 AECOPD and 80 stable COPD patients in respiratory medicine department at tertiary care hospital in north India. PCT levels were measured in serum by ELISA kit. GraphPad Prism version 6.01 (GraphPad software Inc.; La, Jolla, CA, USA) was used for analysis of data.

Results

The present study showed that mean serum PCT levels were significantly higher in AECOPD group (1.31 ± 0.79) as compared to stable COPD group (0.1 ± 0.09) (P < 0.001).

Conclusion

The study confirms that PCT levels were higher in AECOPD patients as compared to stable COPD patients. PCT could be used as a biomarker of exacerbations of COPD and can be used to target management and guiding the treatment in patients with acute exacerbations of COPD.

Potential of serum procalcitonin in predicting bacterial exacerbation and guiding antibiotic administration in severe COPD exacerbations: a systematic review and meta-analysis

Background: The value of procalcitonin (PCT) in the diagnosis of bacterial infections and for determining antibiotic usage among patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is currently unclear. Methods: We systematically reviewed the literature and selected studies that evaluated PCT as a biomarker for predicting bacterial infection and compared PCT-based protocols to determine its application in the initiation or discontinuation of antibiotics. Guidance for systematic reviews from Cochrane and the GRADE were followed to perform this study. Data were pooled and analyzed by using a random-effects or a fixed-effects model based on the heterogeneity. Results: The pooled sensitivity and specificity of PCT in diagnosing respiratory bacterial infections were 0.60 and 0.76, respectively, with the area under the summary receiver operating characteristic curve of 0.77. Subgroup analysis showed that the sensitivity and specificity of PCT for patients in ICU were 0.48 and 0.69, respectively. PCT-based protocols decreased antibiotic prescription (relative risk = 0.66, 95% CI: 0.62-0.71) and total antibiotic exposure (mean difference = -2.60, 95% CI: -4.48-0.72), without affecting clinical outcomes such as treatment failure, length of hospitalization and rates of re-exacerbation or overall mortality. Conclusions: PCT has a moderate ability to distinguish bacterial respiratory infection in patients with AECOPD. PCT-guided algorithm can reduce unnecessary administration of antibiotics without increasing adverse outcomes. However, for patients requiring admission in the ICU, PCT may have a poor diagnostic value, and the PCT-guided algorithm may not effectively and safely reduce the antibiotic exposure.

Serum Procalcitonin Level as a Predictor of Bacterial Infection in Patients with COPD Exacerbation

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is a major cause of mortality and morbidity throughout the world. Although the cause of COPD exacerbations can be bacterial or viral, use of antibiotics in exacerbations remains controversial. Procalcitonin serum level dramatically increases in bacterial infections, but not in viral or noninfectious febrile diseases. The aim of this study is to investigate whether the measurement of procalcitonin can be used to differentiate bacterial from non-bacterial causes of COPD exacerbations.

MATERIALS AND METHODS

Sixty-eight COPD patients admitted to the emergency department of Masih Daneshvari Hospital due to COPD exacerbation were studied. At admission and before prescribing antibiotics, we obtained sputum and blood samples for sputum gram staining and culture and measured serum C-reactive protein and procalcitonin. All results were analyzed by SPSS software version 22.

RESULTS

A total of 68 patients including 51 males and 17 females were studied. From 38.2% of patients a respiratory pathogen was isolated from their sputum and 23.5% of patients had elevated serum procalcitonin values. Using Fisher exact test, we found strong correlation between elevated procalcitonin levels above 0.5 ng/ml and sputum culture results (P < 0.01). We also found strong correlation between elevated procalcitonin levels above 0.5 ng/ml with abnormal C-reactive protein levels in a group of patients with positive sputum culture, using Fisher exact test (P <0.01).

CONCLUSION

As sputum culture and microbiologic studies are time consuming and sometimes expensive, it seems that procalcitonin could be a reliable marker of bacterial infection in COPD exacerbation, although we recommend a larger study with larger sample to consolidate the finding of this study.

The Use of Serum Procalcitonin as a Diagnostic and Prognostic Biomarker in Chronic Obstructive Pulmonary Disease Exacerbations: A Literature Review Update

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are a major complication in COPD patients which can be triggered by bacterial or viral infections, environmental pollutants and other causes. Procalcitonin (PCT), a peptide that markedly increases in cases of bacterial infection, has been extensively investigated as a biomarker in the diagnosis, prognosis and treatment in patients with AECOPD. A number of studies published in the last decade, tried to investigate whether PCT levels can differentiate between bacterial and other causes of exacerbations, if they can be used as a guide for optimal antibiotic therapy and if they can be a tool in the assessment of the severity and the need for further interventions in the management of those patients. This review aims to gather, summarize and critically present all the available data to date.

Comparison of efficiency of inhaled and intravenous corticosteroid on pregnant women with COPD and the effects on the expression of PCT and hs-CRP

The efficiency of inhaled and systemic corticosteroids on pregnant women with chronic obstructive pulmonary disease (COPD) was investigated. The study also compared the effects of the administration on the expression of inflammatory mediator procalcitonin (PCT) and high-sensitivity C-reactive protein (hs-CRP). A total of 120 pregnant COPD patients were recruited and randomly allocated into the following three groups: Intravenous corticosteroid treatment group (n=42), inhaled corticosteroid treatment group (n=38), and control group (without any corticosteroid treatment, n=40). Patients of the all three groups received symptomatic supportive treatments including oxygen therapy, anti-infection therapy, expectorant, and bronchodilator. The serum PCT and hs-CRP expression levels were measured before treatment and after 7 days of treatment. Moreover, the clinical parameters such as symptoms, blood gas analysis parameters, pulmonary function indexes, fasting blood glucose (FBG) and adverse reactions were recorded. The overall clinical effective rates of the group received budesonide inhalation and the group receiving systemic methylprednisolone treatment were comparable. Both treatments were able to reduce the levels of inflammatory mediators, hs-CRP and PCT. On the other hand, treatments increased PaO₂ of arterial blood gas while reducing PaCO₂, thereby improving the lung function (FEV1% pred and FEV1/FVC) (P>0.05). The study observed that the FBG levels in COPD patients receiving systemic corticosteroid treatment were significantly increased, while budesonide inhalation did not significantly affect the FBG levels. In addition, rates of adverse events (such as mouth dry, oral ulcers, hoarseness) of systemic corticosteroid treatment group were significantly higher than those in inhaled corticosteroid treatment group and control group (38.1% vs. 17.5% vs. 5.0%, comparison between groups: P<0.05). In conclusion, inhaled and systemic use of corticosteroid both significantly improved dyspnea and other clinical symptoms of pregnant COPD patients by increasing oxygen partial pressure, correcting hypoxemia, and enhancing lung function. Moreover, fewer adverse reactions were observed with inhaled corticosteroid treatment, suggesting that inhaled administration is a relatively good, safe and effective treatment for pregnant COPD patients.

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.

Antimicrobial stewardship for hospitalized patients with viral respiratory tract infections

BACKGROUND

The purpose of this study was to implement a targeted antimicrobial stewardship intervention for patients with a viral respiratory tract infection.

METHODS

This was a quasi-experimental before and after audit and feedback intervention of adult inpatients with a positive polymerase chain reaction for a respiratory virus in 2 acute care hospitals in Vancouver, Canada. Audit and feedback was implemented based on 2 criteria: microbiology (no positive bacterial cultures) and chest imaging (absence of pneumonia or consolidation on radiology dictation). A chart review was conducted to assess for days of antibiotics postviral diagnosis. Outcomes including length of stay, intensive care unit admission within 14 days, mechanical ventilation within 14 days, antibiotics prescribed within 14 days, Clostridium difficile infection diagnosed within 30 days, and readmission within 30 days were also reviewed in comparison with the previous year.

RESULTS

Antimicrobial stewardship recommendations for hospitalized patients with viral respiratory tract infections were accepted for 77% of cases. This targeted approach based on easily assessed parameters translated into a 1.3-day (95% confidence interval, 0.3-2.3; P < .01) decrease in mean days of antibiotics postviral diagnosis compared with the previous year without systematic interventions. Compared with the previous year, no differences were identified for adverse outcomes associated with the intervention.

CONCLUSIONS

A targeted antimicrobial stewardship intervention integrating virology testing with the treating physician facilitated a reduction in duration of antibiotic treatment for viral respiratory tract infections.

Procalcitonin to guide antibiotic administration in COPD exacerbations: a meta-analysis

Challenges in the differentiation of the aetiology of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have led to significant overuse of antibiotics. Serum procalcitonin, released in response to bacterial infections, but not viral infections, could possibly identify AECOPD requiring antibiotics. In this meta-analysis we assessed the clinical effectiveness of procalcitonin-based protocols to initiate or discontinue antibiotics in patients presenting with AECOPD.Based on a prospectively registered protocol, we reviewed the literature and selected randomised or quasi-randomised trials comparing procalcitonin-based protocols to initiate or discontinue antibiotics versus standard care in AECOPD. We followed Cochrane and GRADE (Grading of Recommendations, Assessment, Development and Evaluation) guidance to assess risk of bias, quality of evidence and to perform meta-analyses.We included eight trials evaluating 1062 patients with AECOPD. Procalcitonin-based protocols decreased antibiotic prescription (relative risk (RR) 0.56, 95% CI 0.43-0.73) and total antibiotic exposure (mean difference (MD) -3.83, 95% CI (-4.32--3.35)), without affecting clinical outcomes such as rate of treatment failure (RR 0.81, 0.62-1.06), length of hospitalisation (MD -0.76, -1.95-0.43), exacerbation recurrence rate (RR 0.96, 0.69-1.35) or mortality (RR 0.99, 0.58-1.69). However, the quality of the available evidence is low to moderate, because of methodological limitations and small overall study population.Procalcitonin-based protocols appear to be clinically effective; however, confirmatory trials with rigorous methodology are required.

[Multicenter clinical efficacy observation of integrated Traditional Chinese Medicine-Western Medicine treatment in acute onset period of pulmonary heart disease]

OBJECTIVE

To evaluate the efficacy of integrated Traditional Chinese Medicine-Western Medicine (TCM-WM) in the treatment of acute onset pulmonary heart disease (PHD).

METHODS

A total of 240 patients met the inclusion criteria and were enrolled. These inpatients were divided into group A (treatment group) and B (control group) in order of admission according to the principles of randomization and control. The research was performed simultaneously in three hospitals. Two groups were given basic treatment that included: controlled oxygen therapy, active and effective anti-infection, maintaining airway patency, correcting O2 deficiency and CO2 retention, correcting acid-base imbalance and electrolyte disturbance, reducing pulmonary hypertension and treating right heart failure, nutritional support and treatment of.complications. Group A was given basic treatment and integrated Traditional Chinese Medicine (TCM) differentiating therapy; group B was given basic therapy and a placebo that was similar in appearance and taste to TCM medicinal broth of pharmaceutical preparations, provided by Yibin Pharmaceutical Company (Yibin, China, Wuliangye Group).

RESULTS

The mortality in the treatment group decreased by 4.98% compared with the control group. The treatment group reported improved ventilation, corrected hypoxemia, improved nutritional status and promoted digestive functions. It also significantly improved the patient's self-life skills, improved the patient's quality of life and could shorten the length of hospital stay.

CONCLUSION

Comprehensive integrated TCM-WM treatment showed good clinical efficacy toward the acute onset period of PHD patients.

Host Biomarkers for Distinguishing Bacterial from Non-Bacterial Causes of Acute Febrile Illness: A Comprehensive Review

Background

In resource limited settings acute febrile illnesses are often treated empirically due to a lack of reliable, rapid point-of-care diagnostics. This contributes to the indiscriminate use of antimicrobial drugs and poor treatment outcomes. The aim of this comprehensive review was to summarize the diagnostic performance of host biomarkers capable of differentiating bacterial from non-bacterial infections to guide the use of antibiotics.

Methods

Online databases of published literature were searched from January 2010 through April 2015. English language studies that evaluated the performance of one or more host biomarker in differentiating bacterial from non-bacterial infection in patients were included. Key information extracted included author information, study methods, population, pathogens, clinical information, and biomarker performance data. Study quality was assessed using a combination of validated criteria from the QUADAS and Lijmer checklists. Biomarkers were categorized as hematologic factors, inflammatory molecules, cytokines, cell surface or metabolic markers, other host biomarkers, host transcripts, clinical biometrics, and combinations of markers.

Findings

Of the 193 citations identified, 59 studies that evaluated over 112 host biomarkers were selected. Most studies involved patient populations from high-income countries, while 19% involved populations from low- and middle-income countries. The most frequently evaluated host biomarkers were C-reactive protein (61%), white blood cell count (44%) and procalcitonin (34%). Study quality scores ranged from 23.1% to 92.3%. There were 9 high performance host biomarkers or combinations, with sensitivity and specificity of ≥85% or either sensitivity or specificity was reported to be 100%. Five host biomarkers were considered weak markers as they lacked statistically significant performance in discriminating between bacterial and non-bacterial infections.

Discussion

This manuscript provides a summary of host biomarkers to differentiate bacterial from non-bacterial infections in patients with acute febrile illness. Findings provide a basis for prioritizing efforts for further research, assay development and eventual commercialization of rapid point-of-care tests to guide use of antimicrobials. This review also highlights gaps in current knowledge that should be addressed to further improve management of febrile patients.

Evaluation of new laboratory tests to discriminate bacterial from nonbacterial chronic obstructive pulmonary disease exacerbations

INTRODUCTIONS

Discriminating bacterial from nonbacterial acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is difficult, causing antibiotics overuse and bacterial resistance. Sputum cultures are of limited use because results take time. In our hospital, only leukocyte concentration and CRP are laboratory parameters evaluated in AECOPD. We evaluated additional tests to discriminate bacterial vs. nonbacterial AECOPD: 5-part leukocyte differentiation (hematology analyzer), leukocyte differentiation using flow cytometry (Leukoflow, Cytodiff), Leuko64 kit, and procalcitonin.

METHODS

Retrospectively, patients were classified as bacterial or nonbacterial AECOPD. ROC analyses tested how the additional tests discriminate these groups.

RESULTS

Twenty-two AECOPD were classified as bacterial and 23 as nonbacterial. From the additional tests, basophil percentage (Cytodiff) has superior AUC (0.800). At a cutoff resulting in ≥90% sensitivity, neutrophil/lymphocyte ratio (AUC:0.755) and CD4-positive T cells (Leukoflow, AUC:0.747) have the highest specificity (57%). Both neutrophil mean volume and standard deviation (Cell Population Data, DxH800 hematology analyzer) had good combined sensitivity and specificity (AUC:0.846/0.804, 91% sensitivity, 69% specificity). Addition of leukocyte populations and procalcitonin to CRP in regression models (AUC: 0.907/0.876/0.890) increased specificity compared to CRP alone (71% or 73% vs. 39%).

CONCLUSION

No additional test has sufficient accuracy on its own to predict bacterial AECOPD. Combining CRP with several parameters from the additional tests may improve this.

A Systematic Review of Diagnostic Biomarkers of COPD Exacerbation

The aims of this systematic review were to determine which blood-based molecules have been evaluated as possible biomarkers to diagnose chronic obstructive pulmonary disease (COPD) exacerbations (AECOPD) and to ascertain the quality of these biomarker publications. Patients of interest were those that have been diagnosed with COPD. MEDLINE, EMBASE, and CINAHL databases were searched systematically through February 2015 for publications relating to AECOPD diagnostic biomarkers. We used a modified guideline for the REporting of tumor MARKer Studies (mREMARK) to assess study quality. Additional components of quality included the reporting of findings in a replication cohort and the use of receiver-operating characteristics area-under-the curve statistics in evaluating performance. 59 studies were included, in which the most studied biomarkers were C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). CRP showed consistent elevations in AECOPD compared to control subjects, while IL-6 and TNF-α had variable statistical significance and results. mREMARK scores ranged from 6 to 18 (median score of 13). 12 articles reported ROC analyses and only one study employed a replication cohort to confirm biomarker performance. Studies of AECOPD diagnostic biomarkers remain inconsistent in their reporting, with few studies employing ROC analyses and even fewer demonstrating replication in independent cohorts.

Meta-analysis and systematic review of procalcitonin-guided treatment in acute exacerbation of chronic obstructive pulmonary disease

INTRODUCTION

To evaluate the method of procalcitonin (PCT)-guided treatment on antibiotics in acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

METHODS

Database including PubMed, EMBASE, and the Cochrane Central Register of Controlled Trails were searched to find relevant trails. Randomized and quasi-randomized trials of PCT-guided treatment in adult patients with AECOPD were included. Effects on primary outcome (i.e., antibiotic prescriptions, mortality, and clinical success) were accessed in this meta-analysis.

RESULTS

Four trials involving 679 patients were included. PCT-guided treatment significantly reduced antibiotic use (OR 0.26, 95% CI 0.14-0.50, P < 0.0001) in comparison to standard treatment, without increasing clinical failure (OR 1.10, 95% CI 0.70-1.74, P = 0.68; I²  = 0%) and mortality (OR 0.86, 95% CI 0.44-1.68, P = 0.66). The rate of readmission and exacerbation at follow-up period was similar in both groups.

CONCLUSION

Results from this meta-analysis suggest PCT-guided treatment can safely reduce antibiotic overuse in patients with AECOPD.

Postobstructive Pneumonia: An Underdescribed Syndrome

Background. Postobstructive community-acquired pneumonia (PO-CAP) is relatively common in clinical practice. The clinical syndrome is poorly defined, and the role of infection as a cause of the infiltrate is uncertain. We prospectively studied patients with PO-CAP and compared them to a cohort of patients with bacterial community-acquired pneumonia (B-CAP).

Methods. We prospectively studied patients hospitalized for CAP; 5.4% had PO-CAP, defined as a pulmonary infiltrate occurring distal to an obstructed bronchus. Sputum and blood cultures, viral polymerase chain reaction, urinary antigen tests, and serum procalcitonin (PCT) were done in nearly all cases. Clinical and laboratory characteristics of patients with PO-CAP were compared to those of patients with B-CAP.

Results. In a 2-year period, we identified 30 patients with PO-CAP. Compared to patients with B-CAP, patients with PO-CAP had longer duration of symptoms (median, 14 vs 5 days; P < .001). Weight loss and cavitary lesions were more common (P < .01 for both comparisons) and leukocytosis was less common (P < .01) in patients with PO-CAP. A bacterial pathogen was implicated in only 3 (10%) PO-CAP cases. PCT was <0.25 ng/mL in 19 (63.3%) patients. Although no differences were observed in disease severity or rates of intensive care unit admissions, 30-day mortality was significantly higher in PO-CAP vs B-CAP (40.0% vs 11.7%; P < .01).

Conclusions. Although there is substantial overlap, PO-CAP is a clinical entity distinct from B-CAP; a bacterial cause was identified in only 10% of patients. Our study has important implications for the clinical recognition of patients with PO-CAP, the role of microorganisms as etiologic agents, and the use of antibiotic therapy.

Implications of the inflammatory response for the identification of biomarkers of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by both local and systemic inflammation. Because inflammation plays a critical role in the development, course and severity of COPD, inflammatory markers have the potential to improve the current diagnostic and prognostic approaches. Local inflammation in COPD is characterized by an infiltration of inflammatory cells, with an increased expression of cytokines, chemokines, enzymes, growth factors and adhesion molecules. Systemic low-grade inflammation is another common but nonspecific finding in COPD. Exacerbations of COPD are acute clinical events accompanied by an exaggerated inflammatory response. Future investigations in the field of COPD biomarkers should take into account different study designs and biochemical assays, disease course and duration, variations in symptom severity and timing of measurement.

The clinical impact of the detection of potential etiologic pathogens of community-acquired pneumonia

The etiology of community-acquired pneumonia (CAP) is determined in less than half of the patients based on cultures of sputum and blood plus testing urine for the antigens of Streptococcus pneumoniae and Legionella pneumophila. This study added nasal polymerase chain reaction (PCR) probes for S. pneumoniae, Staphylococcus aureus, and respiratory viruses. Serum procalcitonin (PCT) levels were measured. Pathogens were identified in 78% of the patients. For detection of viruses, patients were randomized to either a 5-virus laboratory-generated PCR bundle or the 17-virus FilmArray PCR platform. The FilmArray PCR platform detected more viruses than the laboratory-generated bundle and did so in less than 2 hours. There were fewer days of antibiotic therapy, P = 0.003, in CAP patients with viral infections and a low serum PCT levels.

Antibiotic Discontinuation Rates Associated with Positive Respiratory Viral Panel and Low Procalcitonin Results in Proven or Suspected Respiratory Infections

INTRODUCTION

The differentiation of viral from bacterial pneumonia is important in determining whether antibiotics are appropriate for treatment of these infections. Advances in diagnostic technologies such as respiratory panels (RP) utilizing polymerase chain reactions to detect viruses and determination of procalcitonin (PCT) concentrations may aid in this differentiation. However, some studies have shown limited impact for this purpose and thus continuation of antibiotics despite results suggesting viral infection. Our objective was to characterize clinician-prescribing behavior at our institution once RP and/or PCT results were known and suggestive of a viral respiratory infection.

METHODS

This retrospective analysis was based upon records of hospitalized patients in whom proven or possible respiratory infections as indicated by RP testing, respiratory bacterial culture or International Statistical Classification of Diseases and Related Health Problems 9th revision codes for acute infectious respiratory illness was documented. Patients evaluated were required to have a RP or PCT within the first 72 h of presentation. Drug orders were evaluated for discontinuation of antibiotic therapy within 48 h of a procalcitonin of <0.25 μg/mL, a positive viral RP result, or both.

RESULTS

Of 4869 patients with PCT and/or RP results, 2031 were included. PCT and RP testing were obtained in 503 and 1823 patients, respectively, with 295 patients having both. Results of these tests suggested 789 patients were potential candidates for antibiotic avoidance. These included 219 with a PCT <0.25 μg/mL, 601 with a positive viral RP result, and 31 with both. Antibiotics were administered to 307 patients (39%) within the first 72 h. In these, antibiotics were discontinued within 48 h of laboratory results availability.

CONCLUSION

These results suggest that positive viral RP and low PCT results are infrequently associated with discontinuation of antibiotic therapy in proven or possible respiratory infections at our institution. Direct interventions with clinicians are likely needed to correct this behavior and decrease unnecessary antibiotic use.

Heterogeneity of chronic obstructive pulmonary disease exacerbations: a two-axes classification proposal

Exacerbations of chronic obstructive pulmonary disease (COPD) are clinically relevant events with therapeutic and prognostic implications. Yet, they are heterogeneous and can need different therapeutic strategies. In this Viewpoint, we propose an admittedly crude approach to a COPD exacerbation classification that might eventually help to define the most appropriate pharmacological treatment and clinical treatment setting for these patients. Our suggestion is to combine a pathobiological axis (biomarkers) to guide treatment decisions (use of antibiotics, steroids, or both) with a clinical axis (severity score) to decide the organisational context in which to optimally treat the patient. Needless to say, this proposal needs to be researched and eventually validated, refined, or disproved, but we hope that this process will contribute to the improvement of personalised treatment for patients with COPD exacerbations.

Procalcitonin and C-reactive protein cannot differentiate bacterial or viral infection in COPD exacerbation requiring emergency department visits

Background

Viral and bacterial infections are the most common causes of chronic obstructive pulmonary disease (COPD) exacerbations. Whether serum inflammatory markers can differentiate bacterial from virus infection in patients with COPD exacerbation requiring emergency department (ED) visits remains controversial.

Methods

Viral culture and polymerase chain reaction (PCR) were used to identify the viruses in the oropharynx of patients with COPD exacerbations. The bacteria were identified by the semiquantitative culture of the expectorated sputum. The peripheral blood white blood cell (WBC) counts, serum C-reactive protein (CRP), procalcitonin (PCT), and clinical symptoms were compared among patients with different types of infections.

Results

Viruses were isolated from 16 (22.2%) of the 72 patients enrolled. The most commonly identified viruses were parainfluenza type 3, influenza A, and rhinovirus. A total of 30 (41.7%) patients had positive bacterial cultures, with the most commonly found bacteria being Haemophilus influenzae and Haemophilus parainfluenzae. Five patients (6.9%) had both positive sputum cultures and virus identification. The WBC, CRP, and PCT levels of the bacteria-positive and bacteria-negative groups were not statistically different. Multivariate analysis showed that patients with increased sputum volumes during the COPD exacerbations had higher risks of recurrent exacerbations in the 1-year period following the first exacerbation.

Conclusion

WBC, CRP, or PCT could not differentiate between bacterial and viral infections in patients with COPD exacerbation requiring ED visits. Those with increased sputum during a COPD exacerbation had higher risks for recurrent exacerbations.

Biomarkers in chronic obstructive pulmonary disease: confusing or useful?

The field of biomarker research has almost reached unmanageable proportions in chronic obstructive pulmonary disease (COPD). The developments of new technology platforms have generated a huge information data base, both cross sectionally and increasingly, longitudinally. The knowledge emerging provides an enormous potential for understanding the disease pathophysiology, for developing markers specific for long-term outcomes, and for developing new therapeutic strategies. However, the excitement must be tempered with an understanding of the limitations of the data collection techniques, and of the variations in disease state, activity, impact, and progression. Nevertheless, the most crucial aspect in interpreting the current literature is the recognition of the relatively superficial characterization of what is a complex group of pathological processes with a common end point of airflow limitation. The current review explores some of these issues together with those areas where real progress appears to have been made, and provides caution on interpretation.

Pneumonic and nonpneumonic exacerbations of COPD: inflammatory response and clinical characteristics

BACKGROUND

Community-acquired pneumonia (CAP) is a frequent event in patients with COPD, although it is not currently considered an acute exacerbation of COPD (AECOPD). To our knowledge, no studies have compared the inflammatory response of patients with COPD who develop CAP or AECOPD. The aim of our study was to compare clinical and evolutive manifestations and biologic signaling of AECOPD and CAP + COPD.

METHODS

Prospective data were collected from 249 consecutively hospitalized patients with COPD. Comparative analyses were performed in patients with AECOPD (n = 133) and patients with CAP + COPD (n = 116). Measures of clinical characteristics, blood biomarkers, and evolution were recorded on admission, after 3 and 30 days, and in a follow-up period of 30 days, 90 days, and 1 year.

RESULTS

Patients with CAP + COPD had higher FEV1 compared with patients with COPD without pneumonia. In-hospital and long-term outcomes (1 year) were similar for both populations. However, patients with AECOPD had more readmissions, and patients with CAP had more prior episodes of pneumonia. At day 1 and day 3, patients with CAP + COPD had significantly (P &lt; .001) higher serum levels of C-reactive protein (CRP), procalcitonin, tumor necrosis factor-α, and IL-6. Repetition of the analyses after stratifying patients based on severity of disease, current inhaled pharmacotherapy, and noninfectious AECOPD cause confirmed higher levels of the same biomarkers in patients with CAP + COPD. Chills, pleuritic pain, sputum purulence, and CRP levels at day 1 were independent clinical predictors of CAP + COPD.

CONCLUSIONS

Our study confirms that two different clinical and inflammatory profiles exist in hospitalized patients with COPD in response to CAP (stronger response) and AECOPD, although with similar short-term and long-term outcomes.

Bacterial complications of respiratory tract viral illness: a comprehensive evaluation

Background. Respiratory tract infection is one of the most common reasons for hospitalization among adults, and recent evidence suggests that many of these illnesses are associated with viruses. Although bacterial infection is known to complicate viral infections, the frequency and impact of mixed viral-bacterial infections has not been well studied.

Methods. Adults hospitalized with respiratory illness during 3 winters underwent comprehensive viral and bacterial testing. This assessment was augmented by measuring the serum level of procalcitonin (PCT) as a marker of bacterial infection. Mixed viral-bacterial infection was defined as a positive viral test result plus a positive bacterial assay result or a serum PCT level of ≥ 0.25 ng/mL on admission or day 2 of hospitalization.

Results. Of 842 hospitalizations (771 patients) evaluated, 348 (41%) had evidence of viral infection. A total of 212 hospitalizations (61%) involved patients with viral infection alone. Of the remaining 136 hospitalizations (39%) involving viral infection, results of bacterial tests were positive in 64 (18%), and PCT analysis identified bacterial infection in an additional 72 (21%). Subjects hospitalized with mixed viral-bacterial infections were older and more commonly received a diagnosis of pneumonia. Over 90% of hospitalizations in both groups involved subjects who received antibiotics. Notably, 4 of 10 deaths among subjects hospitalized with viral infection alone were secondary to complications of Clostridium difficile colitis.

Conclusions. Bacterial coinfection is associated with approximately 40% of viral respiratory tract infections requiring hospitalization. Patients with positive results of viral tests should be carefully evaluated for concomitant bacterial infection. Early empirical antibiotic therapy for patients with an unstable condition is appropriate but is not without risk.