Procalcitonin as a diagnostic marker in acute exacerbation of COPD

Neutrophil-to-Lymphocyte Ratio (NLR), Platelet-to-Lymphocyte Ratio (PLR) and Monocyte-to-Lymphocyte Ratio (MLR) as Biomarkers in Diagnosis Evaluation of Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Retrospective, Observational Study

PURPOSE

Hierarchical management is advocated in China to effectively manage chronic obstructive pulmonary disease (COPD) patients and reduce the incidence and mortality of acute exacerbation of COPD (AE-COPD). However, primary and community hospitals often have limited access to advanced equipment and technology. Complete blood count (CBC), which is commonly used in these hospitals, offers the advantages of being cost-effective and easily accessible. This study aims to evaluate the significance of routine blood indicators in aiding of diagnosing AE-COPD.

PATIENTS AND METHODS

In this research, we enrolled a total of 112 patients diagnosed with AE-COPD, 92 patients with stable COPD, and a control group comprising 60 healthy individuals. Clinical characteristics, CBC parameters, and serum CRP levels were collected within two hours. To assess the associations between NLR/PLR/MLR and CRP by Spearman correlation test. The diagnostic accuracy of NLR, PLR and MLR in AE-COPD was assessed using Receiver Operating Characteristic Curve (ROC) and the area under the curve (AUC). Binary Logistic Regression analysis was conducted for the indicators of NLR, PLR and MLR.

RESULTS

We found that patients with AE-COPD had significantly higher levels of NLR, PLR and MLR in contrast to patients with stable COPD. Additionally, the study revealed a noteworthy correlation between CRP and NLR (rs=0.5319, P<0.001), PLR (rs=0.4424, P<0.001), and MLR (rs=0.4628, P<0.001). By utilizing specific cut-off values, the amalgamation of NLR, PLR and MLR augmented diagnostic sensitivity. Binary logistic regression analysis demonstrated that heightened NLR and MLR act as risk factors for the progression of AE-COPD.

CONCLUSION

The increasing levels of NLR, PLR and MLR could function as biomarkers, akin to CRP, for diagnosis and assessment of acute exacerbations among COPD patients. Further research is required to validate this concept.

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.

Comparison of diagnostic values of procalcitonin, C-reactive protein and blood neutrophil/lymphocyte ratio levels in predicting bacterial infection in hospitalized patients with acute exacerbations of COPD

BACKGROUND

Viral or bacterial upper respiratory infections are the most common cause of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Based on available data, no reliable parameter has been presented to distinguish between bacterial and nonbacterial exacerbations. Therefore, we compared the diagnostic value of procalcitonin (PCT) level, which is a newer marker for predicting bacterial infections in patients with AECOPD, to routine parameters such as C-reactive protein (CRP) levels and the neutrophil/lymphocyte (N/L) ratio.

METHODS

This study included all consecutive patients who were admitted for a diagnosis of AECOPD between January 1 and March 31, 2014. PCT, CRP, and the N/L ratio were assessed in addition to cultures from tracheal aspirates or sputum on the first day of admission. Patients with a pneumonic infiltration on chest radiographs, or an extrapulmonary infection focus, or whose blood samples were not obtained for PCT and/or CRP at the same time as sputum culture were excluded from the study.

RESULTS

A total of 77 patients were included with a mean age of 71.7 ± 9.5 years. Bacteria were isolated in 37.4 % of the patients. Mean PCT levels were significantly higher in patients with positive sputum cultures than in patients with negative sputum cultures. The cut-off values for PCT, CRP, and the N/L ratio for predicting a bacterial infection were 0.40 ng/mL, 91.50 mg/L, and 11.5, respectively; sensitivity was 61, 54, and 61 % respectively; specificity was 67, 52, and 58 %, respectively; and the area under the curve (AUC) values were 0.64, 0.52, and 0.58, respectively. The AUC value of PCT was significantly better for predicting bacterial infection compared with the CRP level or the N/L ratio (p = 0.042).

CONCLUSION

PCT was better than CRP and the N/L ratio for predicting a bacterial infection in hospitalized patients with AECOPD. However, we find PCT not so reliable in predicting bacterial infection in AECOPD due to sensitivity and specificity of less than 80 % and a low AUC value.