Diagnostic value of procalcitonin for bacterial infections in patients undergoing hemodialysis: a systematic review and meta-analysis

Background

The diagnostic value of procalcitonin (PCT) in patients undergoing hemodialysis (HD) remains unclear.

Methods

We searched multiple databases (PubMed, EMBASE, and Cochrane Library) for studies published through August 2021 that evaluated the diagnostic performance of PCT in patients undergoing HD and having suspected bacterial infections. The bivariate fixed effects model was used to calculate pooled sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and summary receiver operating characteristic (SROC) curves.

Results

We identified a total of 1799 studies, of which seven diagnostic studies comprised 1444 patients and 430 bacterial infection episodes. Bivariate pooled sensitivity and specificity for PCT were 0.90 (95% CI: 0.85–0.94) and 0.83 (95% CI: 0.56–0.95), respectively. Furthermore, pooled DOR, PLR, NLR, and area under the curve (AUC) were 47 (95% CI: 11–209), 5.4 (95% CI: 1.7–16.9), 0.12 (95% CI: 0.07–0.20), and 0.92 (95% CI: 0.90–0.94), respectively. We also compared the diagnostic accuracy of PCT and C-reactive protein (CRP), and our results showed that the diagnostic accuracy parameters for PCT were significantly higher than those for CRP.

Conclusions

PCT is a useful marker for diagnosis of bacterial infections in patients undergoing HD at a cutoff value of 1.5 ng/ml.

How should procalcitonin and C-reactive protein levels be interpreted in haemodialysis patients?

BACKGROUND

Procalcitonin (PCT) and C-reactive protein (CRP) are used most widely in the diagnosis/treatment of bacterial infections. These are not infection-specific and may also show increases in other inflammation-causing cases.

AIM

To establish a new cut-off value for PCT and CRP to eliminate confusion in the diagnosis and treatment of bacterial infections in haemodialysis (HD) patients.

METHODS

A total of 1110 patients, 802 with undocumented infection and 308 with documented infection, was included in the study.

RESULTS

A total of 802 patients with undocumented infection had a mean CRP value of 12.2 ± 9.6 mg/dL and a mean PCT value of 0.51 ± 0.96 ng/mL and the 308 patients with documented infection had a mean CRP value of 125.9 ± 83.3 mg/dL and a mean PCT value of 13.9 ± 26.9 ng/mL at the time of admittance. In HD patients, the cut-off values for CRP was determined as 19.15 mg/dL and for PCT as 0.685 ng/mL in the presence of infection. The use of these two parameters in combination (CRP ≥19.15 mg/dL and PCT ≥ 0.685 ng/mL) was found to have 95% positive predictive value (PPV) and 93% negative predictive value (NPV) for the diagnosis of infectious diseases in HD patients. When CRP ≥100 mg/dL and PCT ≥5 ng/mL, this was found to have 100% PPV and 94% NPV for the diagnosis of sepsis in HD patients.

CONCLUSION

We specified PCT and CRP cut-off values with high PPV and NPV for revealing the presence of bacterial infection and sepsis in HD patients.

Association of serum procalcitonin level with in-stent restenosis in patients undergoing bare-metal stent implantation

AIM

Procalcitonin (PCT) is an inflammatory marker and elevated PCT levels are associated with cardiovascular events. We assessed whether PCT level is an independent predictor of bare-metal stent (BMS) in-stent restenosis (ISR).

PATIENTS & METHODS

We evaluated 240 patients undergoing BMS implantation. Serum PCT levels were measured before procedure. Patients were classified as ISR(-) group (n = 120) and ISR(+) group (n = 120).

RESULTS

Serum PCT levels were higher in the ISR (+) group (p < 0.001). At multivariate analysis, PCT (odds ratio [OR] 1.561; p = 0.012), stent length (OR: 1.089), stent diameter (OR: 0.141) and uric acid (OR: 1.465) were independent predictors of ISR.

CONCLUSION

Serum PCT is independently associated with ISR and increased PCT levels may provide useful information for the risk of BMS-ISR.

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.

The Association Between Serum Procalcitonin Levels and Severity of Coronary Artery Disease Assessed by SYNTAX Score in Patients With Acute Coronary Syndrome

The SYNTAX score (SX score) is a useful score for assessing the severity of coronary artery disease (CAD). Previous studies have demonstrated a close relationship between SX score and inflammation. Procalcitonin (PCT) is an early inflammatory marker, especially during sepsis. Thus, in this study, we aimed to investigate the relationship between SX score and serum PCT levels. A total of 545 patients were enrolled in this prospective cross-sectional study and were divided into 2 subgroups, according to their SX score. Serum PCT and high-sensitivity C-reactive protein levels were measured. Serum PCT levels were higher in the high SX score group compared to the low–intermediate SX score group ( P < .001). Serum PCT levels were an independent predictor of a high SX score in patients with acute coronary syndrome ( P = .001). As patients with a higher SX score had increased serum PCT levels on admission, serum PCT may be useful for identifying patients with severe CAD.

Interleukin-18, CRP and procalcitonin levels in vesicoureteral reflux and reflux nephropathy

BACKGROUND

Some patients with vesicoureteral reflux (VUR) develop reflux nephropathy (RN) and a number of them progress to chronic kidney disease (CKD). However, it is unclear to predict which patient will develop RN and/or CKD. The aim of this study is to evaluate the role of Interleukin-18 (IL-18), C-reactive protein (CRP) and procalcitonin (PCT) as an indicator of RN in VUR.

METHODS

Ninety-three children aged 3.5-16 years with primary VUR were enrolled. Patients were divided into two groups according to the presence of renal scarring (RS). CRP, PCT, blood urea nitrogen (BUN), serum creatinine (Scr), urinary protein (Up), creatinine (Ucr) and microalbumin (Umalb), serum and urine IL-18 levels were determined during urinary tract infection (UTI) free episode.

RESULTS

BUN, Scr, Up/Ucr and Umalb/Ucr concentrations were higher whereas calculated creatinine clearance (Ccr) values were lower in RS (+) group compared to RS (-) group. CRP, PCT, serum and urine IL-18 levels and mean urine IL-18/Cr concentrations were similar in both groups. Serum and urine IL-18 levels did not differ according to the grade of VUR. No significant correlation was found between CRP, PCT and IL-18.

CONCLUSIONS

Proteinuria and microalbuminuria are valuable hallmarks of RN. CRP and PCT seem not to be reliable indicators of RN in VUR patients. Moreover, serum and urine IL-18 might not predict RN.

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.

Changes in serum procalcitonin and C-reactive protein following antimicrobial therapy as a guide to antibiotic duration in the critically ill: a prospective evaluation

Serial procalcitonin is reported to be useful to titrate duration of antibiotic therapy in the non critically ill patient with pneumonia. The aim of this study was to examine the relationship between antibiotic therapy and serial serum procalcitonin concentrations in a cohort of critically ill septic patients and examine for any differences between culture positive (CP) and culture negative (CN) sepsis. Seventy-five critically ill patients with suspected sepsis were enrolled in this prospective observational study. Serial procalcitonin and C-reactive protein assays were measured on days one, three, five, seven, 10 and 14. The mean duration of antibiotic therapy was similar in the two groups (10.4 +/- 5.1 (CP) vs. 8.4 +/- 5.1 (CN) days, P = 0.09). Serum procalcitonin concentrations were significantly higher at baseline in the CP than the CN group (14.9 +/- 22.9 vs. 6.8 +/- 21.5 ng/ml, P = 0.04). During the study period, serum concentrations of procalcitonin and C-reactive protein declined in both groups. Serum procalcitonin consistently remained higher in the CP group (P < 0.05) and did not return to normal values. In the CN group, procalcitonin concentrations fell below 0.5 only on day 10. There was no significant difference in C-reactive protein profile between the two groups. Four patients in the CP group (11%) had relapse of sepsis. The mean procalcitonins in the relapsed subgroup were lower than those in the remission subgroup (P = 0.02). Therapy for proven or presumed infections was associated with declining serum procalcitonin and C-reactive protein in critically ill septic patients. The marked variability and overlap in plasma profile of these markers between CP and CN sepsis makes it difficult to define a nadir plasma concentration at which one can recommend discontinuation of antibiotic therapy.

Strong correlation of B2-microglobulin (B2-m) with procalcitonin (PCT) in the serum of chronic hemodialysis patients: a role for infections in the dialysis-related amyloidosis?

INTRODUCTION

Infections trigger the activation of defensive cells capable to produce and release B(2)-microglobulin (B(2)-m). Procalcitonin (PCT), secreted by a wide range of human cells, included the aforementioned defensive cells, is generally considered a sensitive and specific marker of infection. In this prospective study, we examined the possibility that infections, as detected by increased levels of PCT, increase the serum levels of B(2)-m in chronic hemodialysis (CHD) patients, possibly affecting the rate of progression of dialysis-related amyloidosis (DRA).

METHODS

For a period of four months, 76 CHD patients, 45 men/31 women, mean age 63 +/- 15.7 years, with no residual renal function and in HD for 46 +/- 50 months were studied bimonthly. Blood was drawn, at baseline T(0), two months T(2), and four months T(4), for measuring hematocrit (Ht), white blood cells (WBC), erythrocyte sedimentation rate (ESR), blood urea and serum creatinine, protein (albumin, globulin), C-reactive protein (CRP), and PCT kappa alpha iota B(2)-m. Any events (especially infections) in the preceding 10-day period were recorded.

RESULTS

At baseline, 100% of all B(2)-m measurements were abnormal (>2.4 mg/L), 13.4% of PCT values were increased (>1.5 ng/mL), and 49.4% of CRP values exceeded the lower limit of 5 mg/L with no statistically significant differences between the results of the three periods of the study. Statistically significant, in all periods, was the linear positive correlation of B(2)-m with PCT (T[0]: p < 0.001, T[2]: p < 0.004, T[4]: p < 0.001). Also, statistically significant (p < 0.005) was the positive correlation of B(2)-m to HD vintage.

CONCLUSIONS

In this study, the strong positive correlation of B(2)-m to PCT probably signifies that the (mainly subclinical) infections increase B(2)-m production in CHD patients intensifying the problem of HD-related amyloidosis.

Clinical indications for plasma protein assays: transthyretin (prealbumin) in inflammation and malnutrition

A large number of circumstances are associated with reduced serum concentrations of transthyretin (TTR), or prealbumin. The most common of these is the acute phase response, which may be due to inflammation, malignancy, trauma, or many other disorders. Some studies have shown a decrease in hospital stay with nutritional therapy based on TTR concentrations, but many recent studies have shown that concentrations of albumin, transferrin, and transthyretin correlate with severity of the underlying disease rather than with anthropometric indicators of hypo- or malnutrition. There are few if any conditions in which the concentration of this protein by itself is more helpful in diagnosis, prognosis, or follow up than are other clinical findings. In the majority of cases, the serum concentration of C-reactive protein is adequate for detection and monitoring of acute phase responses and for prognosis. Although over diagnosis and treatment of presumed protein energy malnutrition is probably not detrimental to most patients, the failure to detect other causes of decreased concentrations (such as serious bacterial infections or malignancy) of the so-called visceral or hepatic proteins could possibly result in increased morbidity or even mortality. In addition to these caveats, assays for TTR have a relatively high level of uncertainty ("imprecision"). Clinical evaluation--history and physical examination--should remain the mainstay of nutritional assessment.

Procalcitonin serum levels in children undergoing chronic haemodialysis

Infections account for considerable morbidity and mortality in patients requiring haemodialysis (HD). Procalcitonin (PCT)-a low molecular weight protein of 13 kDa-helps one to distinguish viral from bacterial infections and to evaluate the severity of bacterial infections. We investigated (1) PCT baseline levels in eight children undergoing chronic HD with high-flux membranes and (2) changes in the serum levels of PCT, C-reactive protein (CRP) and beta-2-microglobulin (beta2-MG)-a peptide with biochemical characteristics similar to those of PCT-before and after haemodialysis sessions. Blood sampling was performed three times in the mid-week session. Serum PCT of the seven uninfected children before HD sessions was increased (0.75+/-0.07 ng/ml), whereas CRP levels were normal. PCT after dialysis decreased significantly by 40% (P<0.0001) compared with initial values, whereas CRP levels before and after HD were not different. beta2-MG decreased by 70%, probably due to different biochemical properties of both proteins. PCT serum levels 15 min and 60 min after the HD session remained unchanged in comparison with those at the end of the HD session, suggesting accumulation of PCT between HD sessions rather than HD-induced production to be responsible for the increased baseline PCT serum levels. We concluded that CRP serum levels were not affected by HD in our group. Moderately elevated baseline PCT serum levels that are presumably due to reduced renal clearance and uraemia and dialysis-ability of PCT should be taken into consideration. However, increase of serum PCT in patients with severe bacterial infections is generally massive (10-fold to 1,000-fold), suggesting a low risk for false negative results in such cases.