Evaluation of Salivary Biomarkers and Spirometry for Diagnosing COPD in Non-Smokers and Smokers of Polish Origin

Chronic obstructive pulmonary disease (COPD) is a prevalent respiratory condition with global implications. Accurate and timely diagnosis is critical; however, traditional diagnostic methods (based on spirometry) show limitations, prompting the search for predictive biomarkers and modern diagnostic techniques. This study explored the validation of COPD-related biomarkers (C-reactive protein, procalcitonin, neutrophil elastase, and alpha-1 antitrypsin) in saliva. A diverse cohort, including healthy non-smokers, healthy smokers, and COPD patients of Polish origin, underwent spirometry and marker analysis. The data correlated with clinical factors, revealing noteworthy relations. Firstly, salivary biomarker levels were compared with serum concentrations, demonstrating notable positive or negative correlations, depending on the factor. Further analysis within healthy individuals revealed associations between biomarker levels, spirometry, and clinical characteristics such as age, sex, and BMI. Next, COPD patients exhibited an enhanced concentration of biomarkers compared to healthy groups. Finally, the study introduced a breathing assessment survey, unveiling significant associations between self-perceived breathing and spirometric and tested parameters. Outcomes emphasized the relevance of subjective experiences in COPD research. In conclusion, this research underscored the potential of salivary biomarkers as diagnostic tools for COPD, offering a non-invasive and accessible alternative to traditional methods. The findings paved the way for improved modern diagnostic approaches.

Effluent lipopolysaccharide is a prompt marker of peritoneal dialysis-related gram-negative peritonitis

BACKGROUND

To investigate the value of effluent lipopolysaccharide (LPS) for early detection of gram-negative peritonitis (GNP) in peritoneal dialysis (PD) patients.

METHODS

PD-related peritonitis episodes occurring between January 2016 and December 2018 were included in the study. Effluent LPS and the other infectious parameters were measured at peritonitis presentation, and peritonitis was categorized as GNP, non-GNP, and culture-negative peritonitis. Receiver operating characteristic (ROC) analysis was employed to evaluate the efficacy of effluent LPS to distinguish GNP.

RESULTS

A total of 161 peritonitis episodes were analyzed, including 49 GNP episodes and 82 non-GNP episodes. In contrast with non-GNP, GNP presented with higher effluent leukocyte count (3236 (1497-6144) vs. 1904 (679-4071) cell mm^-3, p = 0.008), increased effluent LPS (1.552 (0.502-2.500) vs. 0.016 (0.010-0.030) EU mL^-1, p < 0.001), lower blood leukocyte count (9.95 ± 3.18 vs. 11.56 ± 4.37 × 10⁹ L^-1, p = 0.017), greater neutrophil predominance (87.1 ± 4.6% vs. 83.4 ± 7.7%, p = 0.001), and greater "procalcitonin" (PCT, 4.90 (2.20-12.60) vs. 1.00 (0.51-4.07) µg L^-1, p < 0.001). It took 5.2 ± 3.1 h to report the results of effluent LPS. Effluent LPS cutoff value of >0.035 EU mL^-1 showed an area under the ROC curve of 0.972 (95% CI 0.951-0.994, p < 0.001) in differentiating GNP from non-GNP with a sensitivity of 100% and a specificity of 80.5%, and its joint utilization with PCT further increased the specificity (91.4%) to discriminate GNP.

CONCLUSIONS

PD effluent LPS could be an applicable early marker of gram-negative organism-related peritonitis in PD 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.

Procalcitonin level as a surrogate for catheter-related blood stream infection among hemodialysis patients

INTRODUCTION

Catheter-related bloodstream infection (CRBSI) is a frequent complication among hemodialysis patients who usually are presented with nonspecific signs such as fever, rigors, and hypotension. Blood culture will take up to 5 days and antimicrobials will be started. Procalcitonin (PCT) is a valid marker in sepsis. Our goal in this study is to evaluate its usefulness as a diagnostic marker in detecting CRBSI among hemodialysis patients who present with suspected CRBSI.

PATIENTS AND METHODS

Thirty-one hemodialysis patients with suspected CRBSI were enrolled in this study. PCT level was measured at the time of presentation. Patients were divided into two groups according to blood culture results: positive and negative groups. PCT level and other markers for inflammation: white blood cell count (WBC), C-reactive protein (CRP), and ferritin were compared between the two groups. Statistical analysis of variables was performed using the t-test or Mann-Whitney test together with Spearman correlation test.

RESULTS

Thirty-one patients had median age 44.7 ± 2.1 years. They comprised 16 males (52%) and 15 females (48%). Sixteen patients had a positive blood culture result while in 15 it was negative. PCT level was significantly higher in the positive blood culture group (40.0 ± -21.9) (95% confidence interval [CI] 28.4-51.8) while its level was 1.1 ± 1 (95% CI 0.54-1.8) in the negative blood culture group [t(15) = -7, p<0.001). In the positive culture group, there was a correlation between CRP and ferritin (r = -0.58, p = 0.01, n = 16), while no correlation between PCT and other markers of inflammation.

CONCLUSIONS

PCT is a useful marker for diagnosis of CRBSI among hemodialysis patients.

The Role of NGAL in Peritoneal Dialysis Effluent in Early Diagnosis of Peritonitis: Case-Control Study in Peritoneal Dialysis Patients

BACKGROUND

Peritoneal dialysis (PD) is frequently complicated by high rates of peritonitis, which result in hospitalization, technique failure, transfer to hemodialysis, and increased mortality. Early diagnosis, and identification of contributing factors are essential components to increasing effectiveness of care. In previous reports, neutrophil gelatinase-associated lipocalin (NGAL), a lipocalin which is a key player in innate immunity and rapidly detectable in peritoneal dialysis effluent (PDE), has been demonstrated to be a useful tool in the early diagnosis of peritonitis. This study investigates predictive value of PDE NGAL concentration as a prognostic indicator for PD-related peritonitis.

METHODS

A case-control study with 182 PD patients was conducted. Plasma and PDE were analyzed for the following biomarkers: C-reactive protein (CRP), blood procalcitonin (PCT), leucocytes and NGAL in PDE. The cases consisted of patients with suspected peritonitis, while controls were the patients who came to our ambulatory clinic for routine visits without any sign of peritonitis. The episodes of peritonitis were defined in agreement with International Society for Peritoneal Dialysis guidelines. Continuous variables were presented as the median values and interquartile range (IQR). Mann-Whitney U test was used to compare continuous variables. Univariate and multivariate logistic regression were used to evaluate the association of biomarkers with peritonitis. Receiver operating characteristic (ROC) curve analysis was used to calculate area under curve (AUC) for biomarkers. Finally we evaluated sensitivity, and specificity for each biomarker. All statistical analyses were performed with SPSS version 17.0 (SPSS Inc., Chicago, IL, USA).

RESULTS

During the 19-month study, of the 182 patients, 80 had a clinical diagnosis of peritonitis. C-reactive protein levels (p < 0.001), PCT (p < 0.001), NGAL in PDE (p < 0.001), and white blood cells (WBC) in PDE (p < 0.001) were all significantly different in patients with and without peritonitis. In univariate analysis, CRP (odds ratio [OR] 1,339; p = 0.001), PCT (OR 2,473; p < 0,001), WBC in PDE (OR 3,986; p < 0,001), and NGAL in PDE (OR 36.75 p < 0.001) were significantly associated with episodes of peritonitis. In multivariate regression analysis, only WBC (OR 24.84; p = 0,012), and peritoneal NGAL levels (OR 136.6; p = 0,01) were independent predictors of peritonitis events. Moreover, AUC for NGAL in peritoneal effluent was 0,936 (p < 0.001) while AUC for CRP, PCT, and WBC count in peritoneal effluent were 0,704 (p = 0.001), 0.762 (p = 0.039), 0,975 (p < 0.001), respectively. Finally, combined WBC and peritoneal NGAL test increased the specificity (= 96%) of the single test.

CONCLUSIONS

These results identify NGAL in peritoneal effluent as a reliable marker of peritonitis episodes in PD patients. Collectively, our findings demonstrate that the use of peritoneal NGAL cooperatively with current clinical diagnostic tools as a prognostic indicator, presents a valuable diagnostic tool in PD-associated peritonitis.

Significance of serum procalcitonin as biomarker for detection of bacterial peritonitis: a systematic review and meta-analysis

Background

Bacterial peritonitis is serious disease and remains a diagnostic challenge for clinicians. Many studies have highlighted the potential usefulness of procalcitonin (PCT) for identification of bacterial peritonitis, however, the overall diagnostic value of PCT remains unclear. Therefore, we performed a meta-analysis to assess the accuracy of PCT for detection of bacterial peritonitis.

Methods

We performed a systematic searched in MEDLINE, EMBASE, SCOPUS, China Biology Medicine Database (CBM), China National Knowledge Infrastructure Database (CNKI) and Cochrane databases for trials that evaluated the diagnostic role of PCT for bacterial peritonitis. Sensitivity, specificity and other measures of accuracy of PCT were pooled using bivariate random effects models.

Results

Eighteen studies involving 1827 patients were included in the present meta-analysis. The pooled sensitivity and specificity of serum PCT for the diagnosis bacterial peritonitis were 0.83 (95% CI: 0.76–0.89) and 0.92 (95% CI: 0.87–0.96), respectively. The positive likelihood ratio was 11.06 (95% CI: 6.31–19.38), negative likelihood ratio was 0.18 (95% CI: 0.12–0.27) and diagnostic odds ratio (DOR) was 61.52 (95% CI: 27.58–137.21). The area under the receiver operating characteristic curve (AUROC) was 0.94. Use of a common PCT cut-off value could improve the DOR to 75.32 and the AUROC to 0.95. Analysis of the seven studies that measured serum C-reactive protein (CRP) indicated that PCT was more accurate than CRP for the diagnosis of bacterial peritonitis.

Conclusions

Our results indicate that PCT determination is a relatively sensitive and specific test for the diagnosis of bacterial peritonitis. However, with regard to methodological limitations and significant heterogeneity, medical decisions should be based on both clinical findings and PCT test results.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-452) contains supplementary material, which is available to authorized users.

Diagnostic value of serum procalcitonin in patients with chronic renal insufficiency: a systematic review and meta-analysis

BACKGROUND

The diagnostic value of procalcitonin (PCT) for patients with renal impairment is unclear.

METHODS

We searched multiple databases for studies published through December 2011 that evaluated the diagnostic performance of PCT among patients with renal impairment and suspected systemic bacterial infection. We summarized test performance characteristics with the use of forest plots, hierarchical summary receiver operating characteristic (HSROC) curves, and bivariate random effects models.

RESULTS

Our search identified 201 citations, of which seven diagnostic studies evaluated 803 patients and 255 bacterial infection episodes. HSROC-bivariate pooled sensitivity estimates were 73% [95% confidence interval (95% CI) 54-86%] for PCT tests and 78% (95% CI 52-92%) for CRP tests. Pooled specificity estimates were higher for both PCT and CRP tests [PCT, 88% (95% CI 79-93%); CRP, 84% (95% CI, 52-96%)]. The positive likelihood ratio for PCT [likelihood (LR)+ 6.02, 95% CI 3.16-11.47] was sufficiently high to be qualified as a rule-in diagnostic tool, while the negative likelihood ratio was not low enough to be used as a rule-out diagnostic tool (LR- 0.31, 95% CI 0.17-0.57). There was no consistent evidence that PCT was more accurate than CRP test for the diagnosis of systemic infection among patients with renal impairment.

CONCLUSIONS

Both PCT and CRP tests have poor sensitivity but acceptable specificity in diagnosing bacterial infection among patients with renal impairment. Given the poor negative likelihood ratio, its role as a rule-out test is questionable.

Use of procalcitonin in patients on chronic hemodialysis: procalcitonin is not related with increased serum calcitonin

Objectives. To investigate whether procalcitonin (PCT) could be useful for detecting bacterial infections in patients on hemodialysis (HD) and with increased calcitonin (CT). Methods. This prospective study included 42 males and 34 females on HD. The infection group consisted of 15 patients with proven bacterial infections; the other 61 patients were designated as the noninfection group. Serum C-reactive protein (CRP), interleukin (IL)-6, white blood cell (WBC) count, immature and total neutrophil (I/T) ratio, and CT were measured at the beginning of HD, and serum PCT levels at the beginning of HD and after HD. Results. The mean CT level in the both groups was apparently higher than that of nonchronic kidney disease. Significantly higher values between the infection and noninfection groups were seen for CRP, IL-6, WBC, I/T ratio, PCT, and CT. The PCT value of the area under the receiver operating characteristic curve was 0.921, which was significantly higher than the values for CRP (0.853; P < 0.01), IL-6 (0.739; P < 0.01), WBC (0.692; P < 0.01), and I/T ratio (0.584; P < 0.01). Conclusions. PCT was useful marker of bacterial infection in patients on HD and with increased CT. PCT levels should be determined before HD.

Procalcitonin Fails to Differentiate Inflammatory Status or Predict Long-Term Outcomes in Peritoneal Dialysis-Associated Peritonitis

Background

Peritonitis is the major complication in patients undergoing maintenance peritoneal dialysis (PD) and is associated with a significant risk of mortality. Previously, we have shown that patients treated for peritonitis and having prolonged elevation of C-reactive protein (CRP) are associated with higher mortality. The underlying cause for the chronic systemic inflammation remains unknown. We studied serum procalcitonin (PCT), which has been reported as an accurate marker for infection and inflammation, with respect to being a diagnostic and prognostic indicator of persistent chronic inflammation after peritonitis in patients with PD-related peritonitis.

Methods

We conducted a prospective study on PD patients that developed PD-related peritonitis. Blood samples obtained at routine check-up before the onset of peritonitis were taken as baseline (D0). When patients developed PD-related peritonitis, serial blood samples were obtained on day 1 (D1), day 7 (D7), and day 42 (D42) for PCT, CRP, and other inflammatory markers. Patients were followed up for at least 2 years, during which outcomes of peritonitis and causes of death were recorded. Serum levels of CRP and PCT at day 42 were analyzed to assess for long-term prognosis.

Results

35 patients [female 42.9%; mean age 63.8 ± 13.1 years; 12 (34.3%) diabetics] were recruited. The onset of peritonitis was 3.61 ± 3.56 years after PD initiation and median residual renal function at that time was 1.06 (range 0 – 6.1) mL/min. Median total white cell counts in PD effluent at days 1, 3, 7, and 42 were 3505/mm3 (range 377 – 20500/mm3), 297 (8 – 5880)/mm3, 34 (0 – 5290)/mm3, and 10 (0 – 115)/mm3, respectively. Twelve (34.3%) and 14 (40%) PD effluents grew gram-positive and gram-negative micro-organisms respectively; others were culture negative. Median PCT was increased significantly at day 1 [2.00 (0.12 – 58.7) ng/mL, p < 0.001], day 7 [0.76 (0.13 – 15.25) ng/mL, p < 0.001], and day 42 [0.30 (0.13 – 0.79) ng/mL, p = 0.005] compared to baseline [0.20 (0.09 – 0.69) ng/mL]. Seven of 35 patients had false-negative results on day 1 (range 0.12 – 0.46) when PCT <0.5 ng/mL was used as the cutoff value for diagnosing peritonitis. For the long-term prognostic outcome, CRP at day 42 was significantly better than PCT in assessing overall prognosis (CRP: AUC 0.712, 95% CI 0.534 – 0.890 vs PCT: AUC 0.652, 95% CI 0.448 – 0.855). In Kaplan–Meier survival analysis, patients with elevated CRP (>3.0 mg/L) were associated with poorer long-term survival ( p = 0.04) but elevated PCT at the 25th, 50th, or 75th percentiles failed to provide prognostic value.

Conclusions

PD patients after peritonitis may be associated with prolonged systemic inflammation. CRP was a better serum marker for monitoring inflammatory status and predicting long-term prognosis in our study. Although serum PCT is elevated in some patients at the time of peritonitis, its value in making a diagnosis and predicting long-term prognosis remains doubtful.