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

Chronic obstructive pulmonary disease and the airway microbiome: A review for clinicians

Chronic obstructive pulmonary disease (COPD) is a complex heterogeneous disease characterized by progressive airflow limitation and chronic inflammation. The progressive development and long-term repeated acute exacerbation of COPD make many patients still unable to control the deterioration of the disease after active treatment, and even eventually lead to death. An increasing number of studies have shown that the occurrence and development of COPD are closely related to the composition and changes of airway microbiome. This article reviews the interaction between COPD and airway microbiome, the potential mechanisms of interaction, and the treatment methods related to microbiome. We elaborated the internal correlation between airway microbiome and different stages of COPD, inflammatory endotypes, glucocorticoid and antibiotic treatment, analyze the pathophysiological mechanisms such as the "vicious cycle" hypothesis, abnormal inflammation-immune response of the host and the "natural selection" of COPD to airway microbiome, introduce the treatment of COPD related to microbiome and emphasize the predictive value of airway microbiome for the progression, exacerbation and prognosis of COPD, as well as the guiding role for clinical management of patients, in order to provide a new perspective for exploring the pathogenesis of COPD, and also provide clues and guidance for finding new treatment targets.

Respiratory Infection Triggering Severe Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Background

Data are scarce on respiratory infections during severe acute exacerbation of chronic obstructive pulmonary disease (COPD). This study aimed to investigate respiratory infection patterns in the intensive care unit (ICU) and identify variables associated with infection type and patient outcome.

Methods

A retrospective, single-centre cohort study. All patients admitted (2015-2021) to our ICU for severe acute exacerbation of COPD were included. Logistic multivariable regression analysis was performed to predict factors associated with infection and assess the association between infection and outcome.

Results

We included 473 patients: 288 (60.9%) had respiratory infection and 139 (29.4%) required invasive mechanical ventilation. Eighty-nine (30.9%) had viral, 81 (28.1%) bacterial, 34 (11.8%) mixed, and 84 (29.2%) undocumented infections. Forty-seven (9.9%) patients died in the ICU and 67 (14.2%) in hospital. Factors associated with respiratory infection were temperature (odds ratio [+1°C]=1.43, P=0.008) and blood neutrophils (1.07, P=0.002). Male sex (2.21, P=0.02) and blood neutrophils were associated with bacterial infection (1.06, P=0.04). In a multivariable analysis, pneumonia (cause-specific hazard=1.75, P=0.005), respiratory rate (1.17, P=0.04), arterial partial pressure of carbon-dioxide (1.08, P=0.04), and lactate (1.14, P=0.02) were associated with the need for invasive MV. Age (1.03, P=0.03), immunodeficiency (1.96, P=0.02), and altered performance status (1.78, P=0.002) were associated with hospital mortality.

Conclusions

Respiratory infections, 39.9% of which were bacterial, were the main cause of severe acute exacerbation of COPD. Body temperature and blood neutrophils were single markers of infection. Pneumonia was associated with the need for invasive mechanical ventilation but not with hospital mortality, as opposed to age, immunodeficiency, and altered performance status.

Correlation of Serum Clara Cell Secretory Protein 16, Plasma Fibrinogen and Serum Amyloid A with the Severity of Acute Exacerbated COPD and Their Combination in Prognosis Assessment

Introduction

Chronic obstructive pulmonary disease (COPD) has tremendous detrimental effects on patients' quality of life, lung function, disease progression and socioeconomic burden. This study aimed to investigate new serum biomarkers for COPD detection. Three recently emerging biomarkers, including Clara cell secretory protein⁃16 (CC16), plasma fibrinogen (FIB) and serum amyloid A (SAA), were investigated for their potential in stratifying the severity of COPD.

Methods

A total of 220 patients with AECOPD were recruited. Multivariate logistical regression was used to analyze odds ratios of an array of characteristic of patients, including age, global initiative for chronic obstructive lung disease (GOLD), diabetes mellitus, heart diseases, PaCO2, CC16, FIB, and SAA. Correlations of CC16, FIB and SAA levels to each other, GOLD, and PaCO2 were also measured using Spearman correlation. Receiver operating characteristic (ROC)/curve analysis was used to assess sensitivity and specificity of CC16, FIB, SAA and the combination of the three markers in identifying AECOPD patients with poor prognosis.

Results

Our data suggested that age, GOLD, diabetes mellitus, heart diseases, PaCO2, CC16, FIB, and SAA are all significant risk factors for poor prognosis of AECOPD. CC16, FIB and SAA were positively correlated to each other and to GOLD and PaCO2 levels. CC16, FIB and SAA all had a high sensitivity and specificity in identifying patients with a poor prognosis. CC16, FIB and SAA are new markers with potentially high predictive value in AECOPD.

Discussion

Our data support further development of these biomarkers to improve clinical management of AECOPD through providing more accurate prognosis of AECOPD patients that enable timely adjustment of treatment plans.

AACC Guidance Document on the Clinical Use of Procalcitonin

BACKGROUND

Procalcitonin (PCT), a peptide precursor of the hormone calcitonin, is a biomarker whose serum concentrations are elevated in response to systemic inflammation caused by bacterial infection and sepsis. Clinical adoption of PCT in the United States has only recently gained traction with an increasing number of Food and Drug Administration-approved assays and expanded indications for use. There is interest in the use of PCT as an outcomes predictor as well as an antibiotic stewardship tool. However, PCT has limitations in specificity, and conclusions surrounding its utility have been mixed. Further, there is a lack of consensus regarding appropriate timing of measurements and interpretation of results. There is also a lack of method harmonization for PCT assays, and questions remain regarding whether the same clinical decision points may be used across different methods.

CONTENT

This guidance document aims to address key questions related to the use of PCT to manage adult, pediatric, and neonatal patients with suspected sepsis and/or bacterial infections, particularly respiratory infections. The document explores the evidence for PCT utility for antimicrobial therapy decisions and outcomes prediction. Additionally, the document discusses analytical and preanalytical considerations for PCT analysis and confounding factors that may affect the interpretation of PCT results.

SUMMARY

While PCT has been studied widely in various clinical settings, there is considerable variability in study designs and study populations. Evidence to support the use of PCT to guide antibiotic cessation is compelling in the critically ill and in some lower respiratory tract infections but is lacking in other clinical scenarios, and evidence is also limited in the pediatric and neonatal populations. Interpretation of PCT results requires guidance from multidisciplinary care teams of clinicians, pharmacists, and clinical laboratorians.

Management of Acute Exacerbations of Chronic Obstructive Pulmonary Disease in the ICU: An Observational Study From the OUTCOMEREA Database, 1997-2018

OBJECTIVES

Our aim was to describe changes in the management of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) by ICUs and patient outcomes.

DESIGN

We extracted data from the OutcomeRea database concerning patients admitted for AECOPD between 1997 and 2018. We analyzed trends in the use of ventilatory support, corticosteroid therapy, antibiotic therapy, and patient survival.

SETTING

ICUs at 32 French sites.

PATIENTS

One thousand eight hundred sixteen patients in the database had a diagnosis of AECOPD.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Over time, there was a reduction in the prescription of corticosteroids and antibiotics. In a time-series analysis, these changes in practice were not linked with ICU mortality. The proportion of patients treated with invasive mechanical ventilation (IMV) also gradually declined (from 51% between 1997 and 2002 to 35% between 2013 and 2018) with an association between decrease in IMV use and reduction in ICU mortality in a time series analysis. Rates of noninvasive ventilation (NIV) failure decreased with an increase in NIV use to support weaning from IMV. There was a reduction in the median ICU length of stay (from 8 d in 1997-2002 to 4 d in 2013-2018) and in the median total duration of hospitalization (from 23 d in 1997-2002 to 14 d in 2013-2018). We observed an improvement in prognosis, with decreases in overall hospital mortality (from 24% between 1997 and 2002 to 15% between 2013 and 2018), ICU mortality (from 14% between 1997 and 2002 to 10% between 2013 and 2018), and 90-day mortality (from 41% between 1997 and 2002 to 22% between 2013 and 2018).

CONCLUSIONS

The length of stay and mortality of patients with AECOPD admitted to ICUs has decreased over the last 20 years, with a wider use of NIV and a reduction in antibiotic and corticosteroid prescriptions.

Early antibiotic therapy is associated with a lower probability of successful liberation from mechanical ventilation in patients with severe acute exacerbation of chronic obstructive pulmonary disease

Background

While antibiotic therapy is advocated to improve outcomes in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) whenever mechanical ventilation is required, the evidence relies on small studies carried out before the era of widespread antibiotic resistance. Furthermore, the impact of systematic antibiotic therapy on successful weaning from mechanical ventilation was never investigated accounting for the competitive risk of death. The aim of the study was to assess whether early antibiotic therapy (eABT) increases successful mechanical ventilation weaning probability as compared to no eABT, in patients with AECOPD without pneumoniae, using multivariate competitive risk regression.

Methods

Retrospective analysis of patients admitted in 2 intensive care units (ICU) from 2012 to 2020 for AECOPD without pneumonia and requiring mechanical ventilation. eABT was defined as any anti-bacterial chemotherapy introduced during the first 24 h after ICU admission. The primary outcomes were the adjusted subdistribution hazard ratio (SHR) of the probability of being successfully weaned from mechanical ventilation (i.e. non-invasive and invasive ventilation) according to eABT status and accounting for the competitive risk of death.

Results

Three hundred and ninety-one patients were included, of whom 66% received eABT. eABT was associated with a lower probability of successful liberation from mechanical ventilation when accounting for the competing risk of death in multivariate analyses (SHR 0.71 [95% confidence interval, 0.57–0.89], p < 0.01), after adjustment with covariates of disease severity. This association was present in all subgroups except in patients under invasive mechanical ventilation on ICU day-1, in patients with ICU day-1 worst PaCO₂ > 74 torr (median value) and in patients with a documented bacterial bronchitis at ICU admission. Ventilator-free days at day 28, ICU-free days at day 28 and invasive mechanical ventilation-free days at day 28, were significantly lower in the eABT group, while there was no significant difference in mortality at day 28 between patients who received eABT and those who did not.

Conclusions

eABT was independently associated with a lower probability of being successfully weaned from mechanical ventilation, suggesting that the clinician decision to overrule systematic administration of eABT was not associated with a detectable harm in AECOPD ICU patients without pneumonia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01060-2.

Novel Applications of Biomarkers in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is an important health problem and an increasing cause of morbidity and mortality worldwide. Currently, COPD is considered a multisystem disease. Although it primarily affects the lungs, structural and functional changes occur in other organs due to systemic inflammation. It is stated that in patients with COPD, airway and systemic inflammatory markers are increased and that these markers are high are associated with a faster decline in lung functions. In recent years, numerous articles have been published on the discovery and evaluation of biomarkers in COPD. Many markers have also been studied to accurately assess COPD exacerbations and provide effective treatment. However, based on the evidence from published studies, a single molecule has not been adequately validated for broad clinical use.

[Translated article] Spanish COPD Guidelines (GesEPOC) 2021 Update. Diagnosis and Treatment of COPD Exacerbation Syndrome

This article details the GesEPOC 2021 recommendations on the diagnosis and treatment of COPD exacerbation syndrome (CES). The guidelines propose a definition-based syndromic approach, a new classification of severity, and the recognition of different treatable traits (TT), representing a new step toward personalized medicine. The evidence is evaluated using GRADE methodology, with the incorporation of 6 new PICO questions. The diagnostic process comprises four stages: 1) establish a diagnosis of CES, 2) assess the severity of the episode, 3) identify the trigger, and 4) address TTs. This diagnostic process differentiates an outpatient approach, that recommends the inclusion of a basic battery of tests, from a more comprehensive hospital approach, that includes the study of different biomarkers and imaging tests. Bronchodilator treatment for immediate relief of symptoms is considered essential for all patients, while the use of antibiotics, systemic corticosteroids, oxygen therapy, and assisted ventilation and the treatment of comorbidities will vary depending on severity and possible TTs. The use of antibiotics will be indicated particularly if sputum color changes, when ventilatory assistance is required, in cases involving pneumonia, and in patients with elevated C-reactive protein (≥ 20 mg/L). Systemic corticosteroids are recommended in CES that requires admission and are suggested in moderate CES. These drugs are more effective in patients with blood eosinophil counts ≥ 300 cells/mm3. Acute-phase non-invasive mechanical ventilation is specified primarily for patients with CES who develop respiratory acidosis despite initial treatment.

Eosinopenia as a biomarker for antibiotic use in COPD exacerbations: protocol for a retrospective hospital-based cohort study

INTRODUCTION

The acute exacerbation of chronic obstructive pulmonary disease (AECOPD) has a seriously negative impact on patients' healths condition and disease progression. Bacterial infection is closely related to AECOPD, and antibiotics are frequently used in clinical practice. The lack of specific biomarkers for rational antibiotics use always leads to antibiotics abuse in chronic obstructive pulmonary disease (COPD) flare-ups. Eosinopenia has been considered to be related to increased bacterial load of potentially pathogenic organisms at the onset of COPD exacerbations. Therefore, this study aims to investigate whether eosinopenia could be used as a reference for the use of antibiotics in AECOPD.

METHODS AND ANALYSIS

In this study, a hospital-based retrospective cohort design will be adopted to analyse the clinical data of inpatients who are primarily diagnosed with AECOPD in West China Hospital of Sichuan University from 1 January 2010 to 31 December 2020. Relevant data will be extracted from the Clinical Big Data Platform for Scientific Research in West China Hospital, including demographic characteristics, blood eosinophil count, procalcitonin, C reactive protein, microbial cultivation, antibiotics use, length of hospital stay, non-invasive ventilation use, intensive care unit transfer and mortality, etc. The collected data will be described and inferred by corresponding statistical methods according to the data type and their distributions. Multiple binary logistic regression models will be used to analyse the relationship between blood eosinophil count and bacterial infection. The antibiotics use, and patient morbidity and mortality will be compared between patients with or without eosinopenia.

ETHICS AND DISSEMINATION

This study has been approved by the Biomedical Ethics Review Board of West China Hospital of Sichuan University (Approval No. 2020-1056). And the research results will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ChiCTR2000039379.

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.

Nemiralisib in Patients with an Acute Exacerbation of COPD: Placebo-Controlled, Dose-Ranging Study

Background

Management of acute exacerbations of chronic obstructive pulmonary disease (COPD) is sometimes inadequate leading to either prolonged duration and/or an increased risk of recurrent exacerbations in the period following the initial event.

Objective

To evaluate the safety and efficacy of inhaled nemiralisib, a phosphoinositide 3-kinase δ inhibitor, in patients experiencing an acute exacerbation of COPD.

Patients and Methods

In this double-blind, placebo-controlled study, COPD patients (40-80 years, ≥10 pack-year smoking history, current moderate/severe acute exacerbation of COPD requiring standard-of-care treatment) were randomized to placebo or nemiralisib 12.5 µg, 50 µg, 100 µg, 250 µg, 500 µg, or 750 µg (ratio of 3:1:1:1:1:1:3; N=938) for 12 weeks with an exploratory 12-week follow-up period. The primary endpoint was change from baseline in post-bronchodilator FEV1 at week 12. Key secondary endpoints were rate of re-exacerbations, patient-reported outcomes (Exacerbations of Chronic Pulmonary Disease Tool, COPD Assessment Test, St George's Respiratory Questionnaire-COPD), plasma pharmacokinetics (PK) and safety/tolerability.

Results

There was no difference in change from baseline FEV1 at week 12 between the nemiralisib and placebo treatment groups (posterior adjusted median difference, nemiralisib 750 µg and placebo: -0.004L (95% CrI: -0.051L to 0.042L)). Overall, there were also no differences between nemiralisib and placebo in secondary endpoints, including re-exacerbations. Plasma PK increased in a dose proportional manner. The most common adverse event for nemiralisib was post-inhalation cough which appeared to be dose-related.

Conclusion

The addition of nemiralisib to standard-of-care treatment for 12 weeks did not improve lung function or re-exacerbations in patients with, and following an acute exacerbation of COPD. However, this study demonstrated that large clinical trials recruiting acutely exacerbating patients can successfully be conducted.

Spanish COPD Guidelines (GesEPOC) 2021 Update Diagnosis and Treatment af COPD Exacerbation Syndrome

This article details the GesEPOC 2021 recommendations on the diagnosis and treatment of COPD exacerbation syndrome (CES). The guidelines propose a definition-based syndromic approach, a new classification of severity, and the recognition of different treatable traits (TT), representing a new step toward personalized medicine. The evidence is evaluated using GRADE methodology, with the incorporation of 6 new PICO questions. The diagnostic process comprises four stages: 1) establish a diagnosis of CES, 2) assess the severity of the episode, 3) identify the trigger, and 4) address TTs. This diagnostic process differentiates an outpatient approach, that recommends the inclusion of a basic battery of tests, from a more comprehensive hospital approach, that includes the study of different biomarkers and imaging tests. Bronchodilator treatment for immediate relief of symptoms is considered essential for all patients, while the use of antibiotics, systemic corticosteroids, oxygen therapy, and assisted ventilation and the treatment of comorbidities will vary depending on severity and possible TTs. The use of antibiotics will be indicated particularly if sputum color changes, when ventilatory assistance is required, in cases involving pneumonia, and in patients with elevated C-reactive protein (≥ 20 mg/L). Systemic corticosteroids are recommended in CES that requires admission and are suggested in moderate CES. These drugs are more effective in patients with blood eosinophil counts ≥ 300 cells/mm³. Acute-phase non-invasive mechanical ventilation is specified primarily for patients with CES who develop respiratory acidosis despite initial treatment.

Chronic obstructive pulmonary disease exacerbation fundamentals: Diagnosis, treatment, prevention and disease impact

In chronic obstructive pulmonary disease (COPD), exacerbations (ECOPD), characterized by an acute deterioration in respiratory symptoms, are fundamental events impacting negatively upon disease progression, comorbidities, wellbeing and mortality. ECOPD also represent the largest component of the socioeconomic burden of COPD. ECOPDs are currently defined as acute worsening of respiratory symptoms that require additional therapy. Definitions that require worsening of dyspnoea and sputum volume/purulence assume that acute infections, especially respiratory viral infections, and/or exposure to pollutants are the main cause of ECOPD. But other factors may contribute to ECOPD, such as the exacerbation of other respiratory diseases and non-respiratory diseases (e.g., heart failure, thromboembolism). The complexity of worsening dyspnoea has suggested a need to improve the definition of ECOPD using objective measurements such as blood counts and C-reactive protein to improve accuracy of diagnosis and a personalized approach to management. There are three time points when we can intervene to improve outcomes: acutely, to attenuate the length and severity of an established exacerbation; in the aftermath, to prevent early recurrence and readmission, which are common, and in the long-term, establishing preventative measures that reduce the risk of future events. Acute management includes interventions such as corticosteroids or antibiotics and measures to support the respiratory system, including non-invasive ventilation (NIV). Current therapies are broad and better understanding of clinical phenotypes and biomarkers may help to establish a more tailored approach, for example in relation to antibiotic prescription. Other unmet needs include effective treatment for viruses, which commonly cause exacerbations. Preventing early recurrence and readmission to hospital is important and the benefits of interventions such as antibiotics or anti-inflammatories in this period are not established. Domiciliary NIV in those patients who are persistently hypercapnic following discharge and pulmonary rehabilitation can have a positive impact. For long-term prevention, inhaled therapy is key. Dual bronchodilators reduce exacerbation frequency but in patients with continuing exacerbations, triple therapy should be considered, especially if blood eosinophils are elevated. Other options include phosphodiesterase inhibitors and macrolide antibiotics. ECOPD are a key component of the assessment of COPD severity and future outcomes (quality of life, hospitalisations, health care resource utilization, mortality) and are a central component in pharmacological management decisions. Targeted therapies directed towards specific pathways of inflammation are being explored in exacerbation prevention, and this is a promising avenue for future research.

The predictive value of serum procalcitonin for non-invasive positive pressure ventilation in the patients with acute exacerbation of chronic obstructive pulmonary disease

This study aimed to estimate the value of serum procalcitonin (PCT) for non-invasive positive pressure ventilation (NIPPV) prediction in the patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).A total of 220 AECOPD patients were divided into NIPPV group (n = 121) and control group (routine treatment, n = 99) based on the routine standards and physicians' experience. Logistic regression analysis was performed to identify the independent factors for NIPPV treatment. Additionally, the predictive values of the factors were measured through receiver operation characteristic (ROC) curve.NIPPV group and control group showed significant differences in respiratory rate (RR), PaO2, PaCO2, pH, oxygenation index, erythrocyte sedimentation rate (ESR), neutrophil, CRP (C-reaction protein), and PCT (P < .05 for all). PCT, CRP, PaCO2, RR, and neutrophil were independently correlated with NIPPV treatment in AECOPD. ROC curve showed that PCT had superior predictive value, with AUC of 0.899, the sensitivity of 86%, and the specificity of 91.9%. The cut-off value of serum PCT for NIPPV prediction was 88.50 ng/l.AECOPD patients who require NIPPV treatment frequently have high levels of PCT, CRP, PaCO2, RR and neutrophil. Serum PCT may be employed as an indicator for NIPPV treatment in AECOPD patients.

Procalcitonin-guided antibiotic therapy in AECOPD patients: Overview of systematic reviews

BACKGROUND

Procalcitonin (PCT)-guided antibiotic therapy has emerged as mainstream treatment for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and has been studied in many systematic reviews (SRs), but robust conclusion has not been drawn. Thus, this overview aims to summarize and critically evaluate the methodological and evidence quality of SRs on this topic.

METHODS

PubMed, EMBASE, Cochrane library, and Web of science were searched for SRs regarding on PCT-guided antibiotic therapy on AECOPD. Two reviewers assessed the quality of SRs in line with AMSTAR-2 tool and evaluated the strength of evidence quality with the grading of recommendations, assessment, development, and evaluation (GRADE) system for concerned outcomes independently.

RESULTS

Six SRs were published from Jun 2011 to Aug 2019, with from 4 (556 patients) to 15 (2571 patients) randomized controlled trials (RCTs) and retrospective studies. All the included SRs were classified as critical low methodology quality according to A MeaSurement Tool to Assess Systematic Reviews 2 (AMSTAR-2) tool. Most of SRs were absented a list of excluded studies (item 7), and adequate investigation of publication bias and discuss its likely impact on the results (item 15). The PCT-guided antibiotic therapy may reduce antibiotic exposure days and antibiotic prescription rate in patients with AECOPD without affecting treatment success rate or causing adverse events (all-cause mortality, re-admission, re-exacerbation), but the results should be study deeper for the low or moderate evidence quality.

CONCLUSION

Current SRs show that PCT-guided antibiotic therapy could be employed by clinicians in treatment of AECOPD. However, the high-quality evidence of outcomes is lacking, further intensive exploration should be carried out on the precise role of PCT-guided antibiotic therapy on AECOPD.

Clinical Significance of Procalcitonin, C-Reactive Protein, and Interleukin-6 in Helping Guide the Antibiotic Use for Patients with Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Background

Currently, standards of antibiotic use in acute exacerbations of chronic obstructive pulmonary disease (AECOPD) patients are controversial.

Objective

The aim of the present study was to analyze the value of procalcitonin (PCT), C-reactive protein (CRP), and interleukin-6 (IL-6) levels to guide the antibiotic treatment of AECOPD patients.

Methods

A total of 371 patients with COPD or AECOPD were included in the study. Clinical and laboratory data were obtained at admission, 325 AECOPD patients and 46 sCOPD patients treated with antibiotics. The receiver operating curve (ROC) was used to evaluate the relationship between CRP, PCT, and IL-6.

Results

This study included medical record/case control 1, the COPD group (n = 46) and the AECOPD group (n = 325), and medical record control 2, the nonchanged antibiotic group (n = 203) and the changed antibiotic group (n = 61). In case 1, CRP, PCT, and IL-6 levels in the AECOPD group were higher than that in the control group (P < 0.05), while the result of ROC showed that IL-6 had higher AUC values (0.773) and higher sensitivity (71.7%) than other indicators. The specificity of PCT (93.5%) is higher than other indicators. In case 2, ROC curve results showed that the AUC value of IL-6 (0.771) was slightly higher than PCT and CRP. The sensitivity (85.2%) and specificity (65.5%) of CRP were higher than other indicators.

Conclusions

IL-6 and PCT were elevated in AECOPD patients, resulting in a higher diagnostic value for AECOPD. CRP had a higher diagnostic value for antibiotic use in AECOPD patients.

Ability of procalcitonin to distinguish between bacterial and nonbacterial infection in severe acute exacerbation of chronic obstructive pulmonary syndrome in the ICU

Background

To assess the ability of procalcitonin (PCT) to distinguish between bacterial and nonbacterial causes of patients with severe acute exacerbation of COPD (AECOPD) admitted to the ICU, we conducted a retrospective analysis of two prospective studies including 375 patients with severe AECOPD with suspected lower respiratory tract infections. PCT levels were sequentially assessed at the time of inclusion, 6 h after and at day 1, using a sensitive immunoassay. The patients were classified according to the presence of a documented bacterial infection (including bacterial and viral coinfection) (BAC + group), or the absence of a documented bacterial infection (i.e., a documented viral infection alone or absence of a documented pathogen) (BAC- group). The accuracy of PCT levels in predicting bacterial infection (BAC + group) vs no bacterial infection (BAC- group) at different time points was evaluated by receiver operating characteristic (ROC) analysis.

Results

Regarding the entire cohort (n = 375), at any time, the PCT levels significantly differed between groups (Kruskal–Wallis test, p < 0.001). A pairwise comparison showed that PCT levels were significantly higher in patients with bacterial infection (n = 94) than in patients without documented pathogens (n = 218) (p < 0.001). No significant difference was observed between patients with bacterial and viral infection (n = 63). For example, the median PCT-H₀ levels were 0.64 ng/ml [0.22–0.87] in the bacterial group vs 0.24 ng/ml [0.15–0.37] in the viral group and 0.16 ng/mL [0.11–0.22] in the group without documented pathogens. With a c-index of 0.64 (95% CI; 0.58–0.71) at H₀, 0.64 [95% CI 0.57–0.70] at H₆ and 0.63 (95% CI; 0.56–0.69) at H₂₄, PCT had a low accuracy for predicting bacterial infection (BAC + group).

Conclusion

Despite higher PCT levels in severe AECOPD caused by bacterial infection, PCT had a poor accuracy to distinguish between bacterial and nonbacterial infection. Procalcitonin might not be sufficient as a standalone marker for initiating antibiotic treatment in this setting.

Clinical Differences between Eosinophilic and Noneosinophilic Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Multicenter Cross-Sectional Study

METHODS

A total of 643 AECOPD patients were enrolled in this multicenter cross-sectional study. Finally, 455 were included, 214 in the normal-eosinophil AECOPD (NEOS-AECOPD) group, 63 in the mild increased-eosinophil AECOPD (MEOS-AECOPD) group, and 138 in the severe increased-eosinophil AECOPD (SEOS-AECOPD) group. Demographic data, underlying diseases, symptoms, and laboratory findings were collected. Multiple logistic regression analysis was performed to identify the independent factors associated with blood eosinophils (EOS). Correlations between blood EOS and its associated independent factors were evaluated.

RESULTS

The significant differences in 19 factors, including underlying diseases, clinical symptoms, and laboratory parameters, were identified by univariate analysis. Subsequently, multiple logistic regression analysis revealed that lymphocyte%, neutrophil% (NS%), procalcitonin (PCT), and anion gap (AG) were independently associated with blood EOS in AECOPD. Both blood EOS counts and EOS% were significantly correlated with lymphocyte%, NS%, PCT, and AG.

CONCLUSIONS

Collectively, blood EOS was independently associated with lymphocyte%, NS%, PCT, and AG in AECOPD patients. Lymphocyte% was lower, and NS%, PCT, and AG were higher in eosinophilic AECOPD. Our results indicate that viral-dominant infections are the probable major etiologies of eosinophilic AECOPD. Noneosinophilic AECOPD is more likely associated with bacterial-dominant infections. The systemic inflammation in noneosinophilic AECOPD was more severe.

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.

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.