C-reactive protein levels in patients with chronic obstructive pulmonary disease: role of infection

Comparative analysis of lysophospholipid metabolism profiles and clinical characteristics in patients with high vs. low C-reactive protein levels in acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

The precise role of lysophospholipids (LysoPLs) in the pathogenesis of acute exacerbations of Chronic Obstructive Pulmonary Disease (AECOPD) remains unclear. In this study, we sought to elucidate the differences in serum LysoPL metabolite profiles and their correlation with clinical features between patients with low versus high CRP levels.

METHODS

A total of 58 patients with AECOPD were enrolled in the study. Patients were classified into two groups: low CRP group (CRP < 20 mg/L, n = 34) and high CRP group (CRP ≥ 20 mg/L, n = 24). Clinical data were collected, and the LysoPL metabolite profiles were analyzed using Liquid Chromatography-Mass Spectrometry (LC-MS) and identified by matching with the LipidBlast library.

RESULTS

Nineteen differential LysoPLs were initially identified through Student's t-test (p < 0.05 and VIP > 1). Subsequently, four LysoPLs, LPC(16:0), LPE(18:2), LPC(22:0), and LPC(24:0), were identified by FDR adjustment (adjusted p < 0.05). These four lysoPLs had a significant negative correlation with CRP. Integrative analysis revealed that LPC (16:0) and LPC (22:0) correlated with less hypercapnic respiratory failure and ICU admission.

CONCLUSION

AECOPD patients with high CRP levels demonstrated a distinctive LysoPL metabolism profile, with LPC (16:0), LPE(18:2), LPC(22:0), and LPC(24:0) being the most significantly altered lipid molecules. These alterations were associated with poorer clinical outcomes.

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.

Point-of-care COPD diagnostics: biomarkers, sampling, paper-based analytical devices, and perspectives

Chronic obstructive pulmonary disease (COPD) has become the third leading cause of global death. Insufficiency in early diagnosis and treatment of COPD, especially COPD exacerbations, leads to a tremendous economic burden and medical costs. A cost-effective and timely prevention requires decentralized point-of-care diagnostics at patients' residences at affordable prices. Advances in point-of-care (POC) diagnostics may offer new solutions to reduce medical expenditures by measuring salivary and blood biomarkers. Among them, paper-based analytical devices have been the most promising candidates due to their advantages of being affordable, biocompatible, disposable, scalable, and easy to modify. In this review, we present salivary and blood biomarkers related to COPD endotypes and exacerbations, summarize current technologies to collect human whole saliva and whole blood samples, evaluate state-of-the-art paper-based analytical devices that detect COPD biomarkers in saliva and blood, and discuss existing challenges with outlooks on future paper-based POC systems for COPD diagnosis and management.

Clinical Value of FeNO for Pulmonary Hypertension Diagnosis in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Objective

To investigate the clinical value of fractional exhaled nitric oxide (FeNO) in the diagnosis of pulmonary hypertension (PH) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Methods

In this study, the medical records of AECOPD patients were retrospectively reviewed. The patients were divided into AECOPD and AECOPD + PH groups based on the absence or presence of PH. Moreover, FeNO and other indexes were compared between the two groups. The value of FeNO in diagnosing AECOPD with PH was determined using the ROC curve.

Results

A total of 83 patients were enrolled (56 in the AECOPD group and 27 in the AECOPD + PH group). The level of FeNO was significantly lower in the AECOPD + PH group than in the AECOPD group (P = 0.022). Moreover, FeNO level (25.22 ± 8.45 ppb) was higher in the mild PH subgroup than in the moderate (16.64 ± 5.67 ppb, P = 0.005) or severe (11.75 ± 2.36, P = 0.002) PH subgroups. FeNO level was positively correlated with C-reactive protein in AECOPD patients while negatively correlated with brain natriuretic peptide in the AECOPD + PH group. ROC analysis showed that the optimal cutoff value of FeNO in the diagnosis of AECOPD with PH was 24.5 ppb.

Conclusion

FeNO level at admission can act as an indicator for PH diagnosis in AECOPD patients.

2021 Guideline for the Management of COPD Exacerbations: Emergency Medicine Association of Turkey (EMAT) / Turkish Thoracic Society (TTS) Clinical Practice Guideline Task Force

Chronic obstructive pulmonary disease (COPD) is an important public health problem that manifests with exacerbations and causes serious mortality and morbidity in both developed and developing countries. COPD exacerbations usually present to emergency departments, where these patients are diagnosed and treated. Therefore, the Emergency Medicine Association of Turkey and the Turkish Thoracic Society jointly wanted to implement a guideline that evaluates the management of COPD exacerbations according to the current literature and provides evidence-based recommendations. In the management of COPD exacerbations, we aim to support the decision-making process of clinicians dealing with these patients in the emergency setting.

Serum biomarkers in patients with stable and exacerbated COPD-bronchiectasis overlap syndrome

INTRODUCTION

Bronchiectasis (B), commonly seen in patients with chronic obstructive pulmonary disease (COPD), is associated with exacerbations and predicts mortality.

OBJECTIVES

To differentiate patient groups with COPD-(B+) or COPD-(B-) and their exacerbations by using inflammatory markers.

METHODS

Consecutive COPD patients were divided into two groups according to findings on high resolution thorax CT (HRCT) images using Smith and modified Reiff scores. Patients were prospectively followed for possible future exacerbations. Serum fibrinogen, C-reactive protein (CRP), soluble urokinase-type plasminogen activator receptor (suPAR) and Plasminogen activator inhibitor-1 (PAI-1) levels were studied during exacerbation and stable periods.

RESULTS

Eighty-seven patients were included and (85 M, 2 F), mean aged was 68.1 ± 9 (46-87). HRCT confirmed bronchiectasis in 38 (43.7%) patients, most commonly in tubular form (89.4%) and in lower lobes. COPD-B(+) group had lower body mass index (P = 0.036), more advanced stage of disease (P = 0.004) and more frequent exacerbation (P = 0.01). The HRCT scores were correlated with exacerbation rate (r = 0.356, P < 0.05). Fibrinogen and CRP values were higher in exacerbation (P = 0.01, P = 0.013, respectively) especially in COPD-B(+) patients. suPAR and PAI-1 levels were also higher in COPD-B(+) patients although it was not statistically significant.

CONCLUSION

Bronchiectasis is common and causes frequent exacerbations in COPD. Identifying of COPD-B(+) phenotype by HRCT scoring systems has considerable importance for both therapeutic options and clinical outcome of the disease. In addition to fibrinogen and CRP, high serum levels of suPAR and PAI-1 suggest us their significant roles in increased systemic inflammation associated with coexisting of COPD and bronchiectasis.

Acute Phase Proteins as Predictors of Survival in Patients With Acute Exacerbation of Chronic Obstructive Pulmonary Disease Requiring Mechanical Ventilation

Few studies have tried to assess prognostic variables in chronic obstructive pulmonary disease (COPD) patients requiring mechanical ventilation (MV). We evaluated serum C reactive protein, (CRP) pre-albumin (PA) and transferrin (TR) levels in AE-COPD patients requiring MV as prognostic markers of in hospital mortality. 93 AE-COPD patients on MV were evaluated. Detailed clinical evaluation was done daily. Serum CRP & PA were measured on admission, 3rd, 8th and 16th day; TR was measured on admission, 8th and 16th day. Demographics, baseline parameters, CRP, PA and TR were correlated with mortality. Of 93 patients, 49 (52.69%) survived whereas 44 patients (47.31%) died. APACHE II, serum urea & albumin were similar in survivors & non-survivors. Baseline CRP (≥10.5 mg/dl) had sensitivity of 60.5%, specificity of 60.2%, with area under curve (AUC) of 0.62 as predictor of mortality. CRP (≥7 mg/dl) on day 3 had sensitivity (65.5%) and specificity (63.3%) with AUC 0.70 as predictor of mortality. Baseline serum prealbumin was 11.00 (0.09-29.26) mg/dl, and similar in survivors & non-survivors (p = 0.7). Prealbumin at day 8 (n = 50) < 13.5 mg/dl had sensitivity 54.6%, and specificity 51.4% with AUC 0.54 (95% CI 0.34-0.75) as predictor of mortality. Transferrin at day 8 (n = 50) of <148.9 had sensitivity 63.4% and specificity 61.4% with AUC 0.61 with respect to mortality. High CRP levels at baseline, persistently elevated CRP (on day 3) may predict mortality in AE-COPD patients requiring MV. Further studies are required to establish prognostic variables in this patient population.

Procalcitonin, C-reactive protein, PaCO2, and noninvasive mechanical ventilation failure in chronic obstructive pulmonary disease exacerbation

It is unclear whether procalcitonin (PCT) is correlated with noninvasive ventilation (NIV) failure. This retrospective case-control study aimed to compare PCT levels, C-reactive protein (CRP) levels, and PaCO2 in patients (05/2014-03/2015 at the Harrison International Peace Hospital, China) with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and NIV failure/success.This was a retrospective case-control study of patients with AECOPD who required NIV between May 2014 and March 2015. All consecutive patients with AECOPD admitted at the Department of Critical Care Medicine and transferred from the general ward were included in the study. Hemogram, PCT, erythrocyte sedimentation rate (ESR), arterial blood gas (ABG), and CRP levels were measured ≤1 hour before NIV was used. NIV was considered to have failed if at least one of the following criteria was met: cardiac arrest or severe hemodynamic instability; respiratory arrest or gasping; mask intolerance; difficulty in clearing bronchial secretions; or worsening of ABGs or sensorium level during NIV. The factors associated with NIV failure were determined.A total of 376 patients were included: 286 with successful NIV and 90 wither NIV failure. The multivariate analysis showed that PCT (OR = 2.0, 95%CI: 1.2-3.2, P = .006), CRP (OR = 1.2, 95%CI: 1.1-1.3, P < .001), and PaCO2 (OR = 1.1, 95%CI: 1.1-1.2, P < .001) ≤1 hour before NIV were independently associated with NIV failure. The optimal cutoff were 0.31 ng/mL for PCT (sensitivity, 83.3%; specificity, 83.7%), 15.0 mg/mL for CRP (sensitivity, 75.6%; specificity, 93.0%), and 73.5 mm Hg for PaCO2 (sensitivity, 71.1%; specificity, 100%). The area under the curve (AUC) was 0.854 for PCT, 0.849 for CRP, and 0.828 for PaCO2. PCT, CRP, and PaCO2 were used to obtain a combined prediction factor, which achieved an AUC of 0.978 (95%CI: 0.961-0.995).High serum PCT, CRP, and PaCO2 levels predict NIV failure for patients with AECOPD. The combination of these three parameters might enable even more accurate prediction.

Role of Proteases in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is generally associated with progressive destruction of airways and lung parenchyma. Various factors play an important role in the development and progression of COPD, like imbalance of proteases, environmental and genetic factors and oxidative stress. This review is specifically focused on the role of proteases and their imbalance in COPD. There are three classes (serine, mettalo, and cysteine) of proteases involved in COPD. In serine proteases, neutrophil elastase, cathepsin G, and proteinase-3 are involved in destruction of alveolar tissue. Matrix-mettaloproteinase-9, 12, 13, plays an influential role in severity of COPD. Among cysteine proteases, caspase-3, caspases-8 and caspase-9 play an important role in controlling apoptosis. These proteases activities can be regulated by inhibitors like α-1-antitrypsin, neutrophil elastase inhibitor, and leukocyte protease inhibitor. Studies suggest that neutrophil elastase may be a therapeutic target for COPD, and specific inhibitor against this enzyme has potential role to control the disease. Current study suggests that Dipeptidyl Peptidase IV is a potential marker for COPD. Since the expression of proteases and its inhibitors play an important role in COPD pathogenesis, therefore, it is worth investigating the role of proteases and their regulation. Understanding the biochemical basis of COPD pathogenesis using advanced tools in protease biochemistry and aiming toward translational research from bench-to-bedside will have great impact to deal with this health problem.

The levels of serum pro-calcitonin and high-sensitivity C-reactive protein in the early diagnosis of chronic obstructive pulmonary disease during acute exacerbation

The level of of procalcitonin (PCT) and high-sensitivity C-reactive protein (hs-CRP) in the acute exacerbation of COPD (AECOPD) was investigated. Total of 20 patients with acute exacerbation of COPD who were admitted to the Department of Respiratory Medicine, Binzhou Center Hospital in the period of October 2012 to April 2015 were enrolled in the AECOPD group. According to the color of the sputum, the patients with AECOPD were divided into purulent sputum group (n=8) and non-purulent sputum group (n=12). In addition, 15 healthy people from the outpatient medical center were also selected as healthy control group. The levels of serum PCT and hs-CRP in both groups were determined by chemiluminescence and immunoturbidimetry, respectively for the comparison analysis. The serum PCT concentration in AECOPD group was 2.07±5.57 ng/ml, while that in healthy control group was 0.21±0.17 ng/ml. Significant difference was found between serum PCT levels in the two groups (p<0.05). The serum concentration of hs-CRP in AECOPD group was 3.66±3.95 mg/l, which is significantly higher than that of the healthy control group (0.49±0.17) (p<0.001). In AECOPD group, the sensitivity of PCT, hs-CRP and white blood cell count was 75, 40 and 40%, respectively, while the specificity was 80, 100 and 100%, respectively, indicating that PCT has higher sensitivity than hs-CRP and white blood cell count (p<0.05). However, no significant difference was found in specificity among these three methods (p>0.05). PCT level of the patients in purulent sputum group was 3.72±8.80 ng/ml, while that of the patients in non-purulent sputum group was 0.97±1.06 ng/ml. The serum hs-CRP level of patients in purulent sputum group was 4.94±4.60 mg/l, while that of the patients in non-purulent sputum group was (2.80±3.38 mg/l). Both the above parameters showed no significant difference between the purulent sputum group and the non-purulent sputum group (p>0.05). In conclusion, serum PCT and hs-CRP levels can be used as auxiliary diagnosis index for acute exacerbation of COPD. Measurement of serum PCT and hs-CRP levels in patients with AECOPD may be helpful in guiding antibacterial drug therapy.

Platelet function in diabetic and nondiabetic patients with chronic obstructive pulmonary disease: a case control study

BACKGROUND

The effect of association between chronic obstructive pulmonary disease (COPD) and diabetes (DM) on platelet function has not been studied before.

OBJECTIVES

To evaluate the effect of the association between COPD and DM on platelet function and C reactive protein (CRP).

PATIENTS AND METHODS

This case control study was carried out on 110 stable COPD patients who were classified into diabetic and nondiabetic groups. In addition, 40 apparently healthy, age and sex-matched individuals were included in this study as a control group. Chest X-ray, pulmonary function testing and arterial blood gases were done for COPD patients. CRP and complete blood count (CBC) were measured in both patient and control groups.

RESULTS

Mean platelet volume (MPV), platelet distribution width (PDW), platelet crit (PCT) and CRP were significantly higher in COPD patients either nondiabetic or diabetic compared to control group. Moreover, MPV and CRP markers were significantly higher in COPD diabetic patients compared to nondiabetic. There was no significant difference in various laboratory data among different stages of COPD either diabetic or nondiabetic (P > 0.05). In COPD patients, MPV was a significantly positively correlated with CRP and PDW (r = 0.346, P < 0.001; r = 0.510, P < 0.001, respectively) and negatively correlated with PLT count (r = -0.294, P = 0.002).

CONCLUSION

MPV, PDW, PCT and CRP were significantly higher in COPD patients either nondiabetic or diabetic. Platelet function may be modified by the systemic inflammation that associated with COPD. Platelet activation as a prothrombotic sequence of this disease may be used as novel therapeutic target.

Inflammatory Markers and the Risk of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

Systemic inflammatory factors are inconsistently associated with the pathogenesis of chronic obstructive pulmonary disease (COPD). We conducted a systematic review and meta-analysis to summarize the evidence supporting the association between systemic inflammation and the risk of COPD. Pertinent studies were retrieved from PubMed, EmBase, and the Cochrane Library until April 2015. A random-effects model was used to process the data, and the analysis was further stratified by factors affecting these associations. Sensitivity analyses for publication bias were performed. We included 24 observational studies reporting data on 10,677 COPD patients and 28,660 controls. Overall, we noted that COPD was associated with elevated serum CRP (SMD: 1.21; 95%CI: 0.92–1.50; P < 0.001), leukocytes (SMD: 1.07; 95%: 0.25–1.88; P = 0.010), IL-6 (SMD: 0.90; 95%CI: 0.48–1.31; P < 0.001), IL-8 (SMD: 2.34; 95%CI: 0.69–4.00; P = 0.006), and fibrinogen levels (SMD: 0.87; 95%CI: 0.44–1.31; P < 0.001) when compared with control. However, COPD was not significantly associated with TNF-α levels when compared with control (SMD: 0.60; 95%CI: -0.46 to 1.67; P = 0.266). Our findings suggested that COPD was associated with elevated serum CRP, leukocytes, IL-6, IL-8, and fibrinogen, without any significant relationship with TNF-α.

Measurement of C-reactive protein, procalcitonin and neutrophil elastase in saliva of COPD patients and healthy controls: correlation to self-reported wellbeing parameters

BACKGROUND

Saliva is increasingly promoted as an alternative diagnostic bio-sample to blood; however its role in respiratory disease requires elucidation. Our aim was to investigate whether C-reactive protein (CRP), procalcitonin (PCT) and neutrophil elastase (NE) could be measured in unstimulated whole saliva, and to explore differences between COPD patients and controls with normal lung function. We also determined the relationship between these salivary biomarkers and self-reported COPD-relevant metrics.

METHODS

Salivary CRP, PCT and NE levels were measured at each of 3 visits over a 14-day period alongside spirometry and a daily self-assessment dairy in 143 subjects: 20 never-smokers and 25 smokers with normal spirometry; 98 COPD patients [GOLD Stage I, 16; Stage II, 32; Stage III, 39; Stage IV, 11]. Twenty-two randomly selected subjects provided simultaneous blood samples.

RESULTS

Levels of each salivary biomarker could distinguish between the above cohorts. Significant differences remained for salivary CRP and NE (p < 0.05) following adjustment for age, gender, sampling time, gum disease and total co-morbidities; but not for BMI except for salivary NE, which remained higher in smokers compared to non-smokers and stable COPD subjects (p < 0.001). Patients with acute COPD exacerbations had a median increase in all 3 salivary biomarkers (p < 0.001); CRP: median 5.74 ng/ml, [interquartile range (IQR) 2.86-12.25], PCT 0.38 ng/ml, [IQR 0.22-0.94], and NE 539 ng/ml, [IQR 112.25-1264]. In COPD patients, only salivary CRP and PCT levels correlated with breathing scores (r = 0.14, p < 0.02; r = 0.13, p < 0.03 respectively) and sputum features but not with activities of daily living. Salivary CRP and PCT concentrations strongly correlated with serum counterparts [r = 0.82, (95% CI: 0.72-0.87), p < 0.001 by Spearman's; and r = 0.53, (95% CI: 0.33-0.69), p < 0.006 respectively]; salivary NE did not.

CONCLUSIONS

CRP, PCT and NE were reliably and reproducibly measured in saliva, providing clinically-relevant information on health status in COPD; additionally NE distinguished smoking status. All 3 salivary biomarkers increased during COPD exacerbations, with CRP and PCT correlating well with patient-derived clinical metrics. These results provide the conceptual basis for further development of saliva as a viable bio-sample in COPD monitoring and exacerbation management.

Serum C-reactive protein level and distribution in chronic obstructive pulmonary disease versus healthy controls: a case-control study from Iran

Inflammation has a contributive role in the development and progression of chronic obstructive pulmonary disease (COPD).The present study was designed to determine the level and the distribution of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in COPD compared with controls. Ninety patients with COPD presented to an outpatient hospital clinic and 50 controls who were selected among personals of the same hospital entered the study. Serum high sensitive CRP (hs-CRP) was measured by immunoturbidimetric method and the ESR by Westergren method. Receiver operating characteristic curve was applied to determine a cutoff point for differentiation of the COPD and control group. In statistical analysis, the patients and controls were compared regarding levels and distribution of hs-CRP and ESR. Mean age of patients and controls was 67 ± 11.6 and 51.3 ± 6.7 years, respectively (p = 0.001). Mean hs-CRP was significantly higher (4.76 ± 5.6 vs 1.72 ± 1.68 mg/L, p = 0.001) but mean ESR was nonsignificantly higher (9.1 ± 11.2 vs 7.2 ± 7.4 m/h, p = 0.95) in patients than control. Serum hs-CRP at 1.55 mg/L, differentiated patients and controls at sensitivity of 77.3 % and specificity of 60 %. Serum hs-CRP >3 mg/L was observed in 39 (44.3 %) patients and 9 (18 %) controls (p = 0.001) and >6 mg/L in 22 (25 %) patients and 2 (4 %) controls (p = 0.001).Serum hs-CRP was significantly correlated with ESR in patient but not in control group (Spearman correlation coefficient = 0.516, p = 0.001). Serum hs-CRP and ESR was not correlated with age, weigh, smoking, and the severity of COPD. The results of this study indicated a systemic inflammatory process in COPD. Since inflammation has an important contribution in development of future pulmonary and extrapulmonary complications, serum CRP assessment will provide additional information beyond that achieved by conventional method of pulmonary function test.

Surfactant protein D, soluble intercellular adhesion molecule-1 and high-sensitivity C-reactive protein as biomarkers of chronic obstructive pulmonary disease

OBJECTIVE

The aim of this study was to estimate the serum levels of surfactant protein D (SP-D), soluble intercellular adhesion molecule-1 (sICAM-1), and high-sensitivity C-reactive protein (hs-CRP) in patients with chronic obstructive pulmonary disease (COPD) and to assess the correlation of these indices with COPD severity.

SUBJECTS AND METHODS

This analytic cross-sectional study was carried out on 64 COPD male patients, and 26 apparently healthy age-matched males as a control. Chest X-ray, spirometry and arterial blood gases were done for only COPD patients. Serum levels of SP-D, sICAM-1 and hs-CRP were determined by enzyme-linked immunosorbent assay in both patient and control groups.

RESULTS

The serum levels of SP-D, sICAM-1 and hs-CRP were significantly higher in COPD patients than controls (p < 0.001 for each). Also, these biomarkers were significantly higher in stages III and IV compared to either stage I or II (p < 0.01 for each). SP-D was significantly positively correlated with sICAM-1 and hs-CRP (r = 515, p < 0.001; r = 501, p < 0.001, respectively) and negatively correlated with PaO2 (r = -0.651, p < 0.001) and all parameters of spirometry.

CONCLUSION

SP-D, sICAM and hs-CRP were significantly higher in COPD patients in comparison with controls. Moreover, SP-D, sICAM-1, and hs-CRP were significantly negatively correlated with FEV1%. Accordingly, estimation of these biochemical indices may be used as biomarkers for assessment of COPD severity.

Predictors for antibiotic prescribing in patients with exacerbations of COPD in general practice

BACKGROUND

The aim of this study was to describe the antibiotic prescribing rate in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), to analyse predictors for antibiotic prescribing and to explore the influence of the use C-reactive protein (CRP) rapid test.

METHODS

A cross-sectional study was carried out in January and February 2008 in primary care. General practitioners (GPs) from six countries (Denmark, Sweden, Lithuania, Russia, Spain and Argentina) registered all patients with AECOPD during a 3-week period. A multilevel logistic regression model was estimated using two hierarchical levels, (i) patients and (ii) physicians, and was used to analyse the association between antibiotic prescribing and potential predictors for antibiotic use: patients' age and gender, duration and symptoms and signs of exacerbations (fever, cough, dyspnoea, sputum volume and purulence) and the results of the CRP test.

RESULTS

A total of 617 GPs registered 1233 patients with AECOPD. A total of 970 patients (79%) were prescribed antibiotics, varying from 49% (Denmark) to 93% (Russia). The presence of purulent sputum was the strongest predictor for antibiotic treatment (odds ratio [OR] 8.7; 95% confidence interval [CI] 5.9-12.8). CRP determination was carried out mainly in Denmark and Sweden and its use was the strongest protective factor for antibiotic therapy (OR 0.3; 95% CI 0.2-0.6). GPs that used CRP testing weighted purulent sputum lower than GPs who did not use CRP testing. CRP values had a strong influence on the antibiotic prescribing rate.

CONCLUSIONS

Antibiotic treatment for AECOPD is very high. This study shows that GPs performing CRP rapid tests prescribe fewer antibiotics than those who do not.

Association between C-reactive Protein Concentration and Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis

Objective:

This meta-analysis was conducted to summarize the association between the serum concentration of C-reactive protein (CRP) and chronic obstructive pulmonary disease (COPD).

Methods:

MEDLINE®, Cochrane Central Register of Controlled Trials, and EMBASE databases were searched for relevant studies. Data were extracted; pooled weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated.

Results:

Twenty studies were selected for final inclusion in this analysis. Patients with COPD had higher serum CRP concentrations than healthy controls (WMD 4.72 mg/l, 95% CI 2.98, 6.47). In addition, patients with severe COPD had higher serum CRP concentrations than those with moderate COPD (WMD 1.26 mg/l, 95% CI 0.78, 1.73). There was no significant difference in serum CRP concentration between patients with mild and moderate COPD (WMD 0.67 mg/l, 95% CI -0.08, 1.42).

Conclusions:

This meta-analysis suggested that patients with stable COPD had higher serum CRP concentrations than healthy controls. CRP might be an indicator of disease severity in patients with COPD, thus highlighting the importance of measuring serum CRP concentrations in patients with stable COPD.

Detection of microorganisms in exhaled breath condensate during acute exacerbations of COPD

BACKGROUND AND OBJECTIVE

One hallmark of COPD is colonization and infection of the lung. Acute exacerbations of COPD (AECOPD) are acute deteriorations of the chronic disease and are associated with a change of the pulmonary microbial balance. The collection of exhaled breath condensate (EBC) can be used to non-invasively determine markers of lung disease. The aim of the present study was to compare the results of assays based on the detection of microbial nucleic acids from EBC and from spontaneous sputum in patients with AECOPD.

METHODS

EBC and sputa of 29 adults with AECOPD were obtained. Isolated DNA or RNA were used as starting material for the PCR assays to detect Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, Legionella pneumophila, Mycoplasma pneumoniae, Chlamydia pneumoniae, influenza viruses (AH 1, AH 3) and respiratory syncytial virus.

RESULTS

Bacterial or viral nucleic acids were identified in 14 EBC and 21 sputa from 29 patients. Results from EBC did not correlate well with those from sputum. Viral and S. pneumoniae nucleic acids were detected only in sputum, whereas L. pneumophila DNA was only found in EBC. In three EBC and 10 sputa nucleic acids of more than one microorganism was detected.

CONCLUSIONS

Bacterial nucleic acids can be identified in EBC of COPD patients with exacerbations. The results obtained from EBC and sputum did not correlate well.

HsCRP in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is currently the fourth leading cause of death in the United States. As there is systemic as well as local inflammation in COPD patients and evaluating the stage of the disease is not possible by spirometery alone, we evaluated High-Sensitivity C-reactive Protein (HS-CRP) in a group of COPD patients as an available and cost effective auxiliary marker in determining COPD stages.

METHODS

In a cross-sectional study in 160 COPD patients who were admitted for exacerbations in Razi Hospital in Rasht, Data on patients' demographic characteristics, pulmonary function test (PFT) and laboratory results consist of arterial blood gases and HSCRP levels were analyzed.

RESULTS

A significant positive correlation was seen between serum HSCRP level and stages of the disease (as GOLD criteria). There was a significant relationship between HSCRP level and patients' sex, BMI, and smoking history in a way that men and smokers showed higher and patients with normal BMI showed lower HSCRP levels. The patients with higher PCO2 also showed a higher level of serum HSCRP.

CONCLUSIONS

This survey supports the role of HSCRP as a simple auxiliary marker in staging and determining the prognosis of COPD for early management.

Systemic biomarkers in exacerbations of COPD: the evolving clinical challenge

BACKGROUND

Exacerbations of COPD (ECOPD) remain a major cause of mortality and morbidity. Despite advances in the understanding of their pathophysiology, their assessment relies primarily on clinical presentation, which can be variable and difficult to predict. A large number of biomarkers already have been assessed in this context, and some appear to be promising.

METHODS

An online search for articles published until December 2010 was conducted using three terms for ECOPD, five terms for biomarkers, and five terms for the sampling method. Biomarkers were evaluated for their potential role in the establishment and confirmation of the diagnosis of ECOPD, the evaluation of etiology and severity, the prediction of prognosis, and the guidance of treatment decisions.

RESULTS

Several systemic biomarkers have been measured in the context of ECOPD, and most have been found to increase at ECOPD onset and to subside during the course of exacerbations. Correlations have been reported among these biomarkers, but direct associations with clinical variables have been more difficult to establish. Although there are several limitations yet to be addressed, some of the biomarkers, most notably C-reactive protein for the identification of an ECOPD and procalcitonin for antibiotic guidance, may provide clinically relevant information.

CONCLUSIONS

So far, no single biomarker has been able to gain wide acceptance, but some provide clinically useful information. The evaluation of such biomarkers in large decision-making studies is expected to become an area of intense investigation in the near future.

Value of procalcitonin, C-reactive protein, and neopterin in exacerbations of chronic obstructive pulmonary disease

Objective:

The identification of biological markers in order to assess different aspects of COPD is an area of growing interest. The objective of this study was to investigate whether levels of procalcitonin (PCT), C-reactive protein (CRP), and neopterin in COPD patients could be useful in identifying the etiological origin of the exacerbation and assessing its prognosis.

Methods:

We included 318 consecutive COPD patients: 46 in a stable phase, 217 undergoing an exacerbation, and 55 with pneumonia. A serum sample was collected from each patient at the time of being included in the study. A second sample was also collected 1 month later from 23 patients in the exacerbation group. We compared the characteristics, biomarker levels, microbiological findings, and prognosis in each patient group. PCT and CRP were measured using an immunofluorescence assay. Neopterin levels were measured using a competitive immunoassay.

Results:

PCT and CRP showed significant differences among the three patient groups, being higher in patients with pneumonia, followed by patients with exacerbation (P < 0.0001). For the 23 patients with paired samples, PCT and CRP levels decreased 1 month after the exacerbation episode, while neopterin increased. Neopterin showed significantly lower levels in exacerbations with isolation of pathogenic bacteria, but no differences were found for PCT and CRP. No significant differences were found when comparing biomarker levels according to the Gram result: PCT (P = 0.191), CRP (P = 0.080), and neopterin (P = 0.109). However, median values of PCT and CRP were high for Streptococcus pneumoniae, Staphylococcus aureus, and enterobacteria. All biomarkers were higher in patients who died within 1 month after the sample collection than in patients who died later on.

Conclusions:

According to our results, biomarker levels vary depending on the clinical status. However, the identification of the etiology of infectious exacerbation by means of circulating biomarkers is encouraging, but its main disadvantage is the absence of a microbiological gold standard, to definitively demonstrate their value. High biomarker levels during an exacerbation episode correlate with the short-term prognosis, and therefore their measurement can be useful for COPD management.

Local inflammation occurs before systemic inflammation in patients with COPD

BACKGROUND AND OBJECTIVE

COPD is associated not only with an abnormal inflammatory response in the lung but also with systemic inflammation, including systemic oxidative stress, activation of circulating inflammatory cells and increased circulating levels of inflammatory cytokines. Understanding the nature and course of systemic inflammation in COPD is important given the potential for anti-inflammatory therapy. This study explored whether local and systemic inflammation occur concurrently in patients with COPD.

METHODS

Forty-four patients with stable COPD, 10 smoking controls and 10 non-smoking controls were enrolled in this observational study. Induced sputum and peripheral blood samples were obtained simultaneously for measurement of inflammatory cell numbers and the concentrations of IL-6 and CRP.

RESULTS

The total number of cells in the sputum total cell number, percentage of neutrophils and the concentration of IL-6 were significantly higher in smoking controls and patients with COPD than in non-smoking controls (P < 0.05 and P < 0.01, respectively). As the disease stage progressed, airway inflammatory cells and IL-6 levels increased. CRP levels in sputum were significantly higher in stage II, III and IV COPD patients than in smoking and non-smoking controls (P < 0.01). However, the peripheral WCC and percentage of neutrophils were similar in patients with COPD, smoking and non-smoking controls. Circulatory concentrations of IL-6 and CRP in stages III and IV COPD patients were significantly higher than in smoking and non-smoking controls (P < 0.05 and P < 0.01, respectively). Additionally, there were positive correlations between sputum and blood IL-6 and CRP levels (r = 0.566, P < 0.01 and r = 0.443, P < 0.01, respectively).

CONCLUSIONS

The increase in the inflammatory cell population and IL-6 and CRP levels in the airway may occur earlier than in the peripheral blood, and reflect the degree of airflow limitation better than do peripheral blood measurements. Systemic inflammation may be present in patients with severe or very severe COPD.

Bibliography. Current world literature

This bibliography is compiled by clinicians from the journals listed at the end of this publication. It is based on literature entered into our database between 1 November 2007 and 31 October 2008 (articles are generally added to the database about two and a half months after publication). In addition, the bibliography contains every paper annotated by reviewers; these references were obtained from a variety of bibliographic databases and published between the beginning of the review period and the time of going to press. The bibliography has been grouped into topics that relate to the reviews in this issue.

C-reactive protein and copeptin: prognostic predictors in chronic obstructive pulmonary disease exacerbations

PURPOSE OF REVIEW

Acute exacerbation of chronic obstructive pulmonary disease (COPD) is a natural event in the course of COPD and remains a major cause of morbidity and mortality associated with this disease. Clinical criteria that define an acute exacerbation are subjective and open for debate. Identifying biomarkers that would be easily measured and followed in patients with acute exacerbation of COPD seems to be highly attractive. The aim of this review is to assess the role of biomarkers, C-reactive protein (CRP) and copeptin, as prognostic predictors in COPD exacerbations.

RECENT FINDINGS

Many pulmonary biomarkers have been extensively studied in the recent years. CRP and copeptin have gained particular interest. Recent data suggest that CRP is elevated during an acute exacerbation of COPD but CRP alone is neither sensitive nor specific in predicting clinical severity or outcome. Copeptin increases during acute exacerbation of COPD and may correlate with disease severity.

SUMMARY

Further studies are needed to determine the role of CRP and copeptin as biomarkers that aid in diagnosis and clinical outcome in acute exacerbation of COPD.

C-reactive protein velocity following antibiotics in patients with chronic obstructive pulmonary disease exacerbation and community acquired pneumonia

INTRODUCTION

Distinguishing community acquired pneumonia (CAP) from chronic obstructive pulmonary disease (COPD) exacerbation is a challenging task, since fever, productive cough, dyspnea, and leukocytosis are all common features of both conditions. Moreover, chest X-ray might not be sensitive enough. It is therefore quite common for physicians to prescribe unnecessary antibiotics for COPD exacerbation, leading to resistant bacteria and other related adverse affects.

AIM

To study whether CRP levels upon admission and the delta in CRP levels following initiation of antibacterial treatment, could provide an efficient tool for distinguishing CAP from COPD exacerbation.

METHODS

The study group included 36 COPD exacerbation and 49 CAP patients, admitted to a single Internal Medicine department during the years 2004-2006. All patients were treated with cephalosporins and macrolides upon admission.

RESULTS

CRP levels upon admission were significantly higher among CAP patients than among COPD exacerbation patients (111.5+/-104.4 vs. 34.9+/-28.6 mg/l, p<0.0001). CRP levels on the second day of hospitalization, following antibiotic administration to all patients, made a sharp incline in 36.7% of CAP patients compared to only 5.9% of COPD exacerbation patients (p=0.005), and remained unchanged in 61.8% of COPD patients compared to 16.3% of CAP patients (p=0.0006).

CONCLUSIONS

CRP levels upon admission and the delta in CRP levels following initiation of antibacterial treatment could provide an efficient tool for distinguishing CAP from COPD exacerbation.