Diagnostic accuracy of procalcitonin for bacterial pneumonia in children - a systematic review and meta-analysis

Overview of Pediatric Procalcitonin Testing Patterns in a Tertiary Care Children's Hospital

The use of procalcitonin (PCT) has grown over the past decade with increasing reliance on the test to rule out bacterial infection. We retrospectively reviewed the medical records of children <18 years old hospitalized at a tertiary care children's hospital from 2017 to 2019 who had PCT testing performed during their admission. Of 4135 PCT levels collected on 1530 children, 982 (23.7%) were diagnostically low and 1993 (48.1%) were diagnostically elevated. Pediatric intensive care, with 6% of total hospital patients, obtained 41.4% of tests. Thirty-one (2%) patients had an average of 27 PCT levels per patient, accounting for 20% of all tests. Many children had symptoms for which testing is not indicated (eg, skin complaints). The differences in PCT testing by service, inappropriate patterns of repeat testing, and testing performed in patients for whom it is not indicated may identify targets for diagnostic stewardship.

Low Levels of Procalcitonin Are Related to Decreased Antibiotic Use in Children Hospitalized Due to Influenza

Procalcitonin increases in bacterial infections, which are often suspected (though rarely confirmed) in paediatric influenza. We retrospectively verified procalcitonin’s usefulness in antibiotic guidance in children hospitalized due to laboratory-confirmed influenza. The ROC curve analysis evaluated procalcitonin’s performance in terms of antibiotic implementation or continuation in patients who were naive or had been receiving antibiotic treatment prior to hospital admission. We also assessed the procalcitonin’s usefulness to predict lower-respiratory-tract infections (LRTI), the presence of radiologically confirmed pneumonia, an intensive care unit transfer and a fatal outcome. Multiple regression models were built to verify the previously reported procalcitonin cut-off values. The study enrolled 371 children (median age 33 months). The AUC (area under the curve) for antibiotic implementation reached 0.66 (95%CI: 0.58–0.73) and 0.713 (95%CI: 0.6–0.83) for antibiotic continuation; optimal cut-offs (0.4 and 0.23 ng/mL, respectively) resulted in a negative predictive value (NPV) of 79.7% (95%CI: 76.2–82.9%) and 54.6% (95%CI: 45.8–63%), respectively. The use of 0.25 ng/mL as a reference decreased the odds of antibiotic treatment by 67% (95%CI: 43–81%) and 91% (95%CI: 56–98%), respectively. Procalcitonin showed lower AUC for the prediction of LRTI and pneumonia (0.6, 95%CI: 0.53–0.66, and 0.63, 95%CI: 0.56–0.7, respectively), with a moderately high NPV in the latter case (83%, 95%CI: 79.3–86.1%). Procalcitonin use may decrease the antibiotic frequency in hospitalized influenza cases both in terms of antibiotic administration and continuation. Procalcitonin concentrations may suggest bacterial suprainfections at lower concentrations than in adults, and a focus on its rule-out value is of special interest.

An algorithm combining procalcitonin and lung ultrasound improves the diagnosis of bacterial pneumonia in critically ill children: The PROLUSP study, a randomized clinical trial

BACKGROUND

Lung ultrasound (LUS) and procalcitonin (PCT) are independently used to improve accuracy when diagnosing lung infections. The aim of the study was to evaluate the accuracy of a new algorithm combining LUS and PCT for the diagnosis of bacterial pneumonia.

METHODS

Randomized, blinded, comparative effectiveness clinical trial. Children <18 years old with suspected pneumonia admitted to pediatric intensive care unit were included, and randomized into experimental group (EG) or control group (CG) if LUS or chest X-Ray (CXR) were done as the first pulmonary image, respectively. PCT was determined. In patients with bacterial pneumonia, sensitivity, specificity, and predictive values of LUS, CXR, and of both combined with PCT were analyzed and compared. Concordance between the final diagnosis and the diagnosis concluded through the imaging test was assessed.

RESULTS

A total of 194 children, with a median age of 134 (interquartile range [IQR]: 39-554) days, were enrolled, 96 randomized into the EG and 98 into the CG. Bacterial pneumonia was diagnosed in 97 patients. Sensitivity and specificity for bacterial pneumonia diagnosis were 78% (95% confidence interval [CI]: 70-85) and 98% (95% CI: 93-99) for LUS, 85% (95% CI: 78-90) and 53% (95% CI: 43-62) for CXR, 90% (95% CI: 83-94) and 85% (95% CI: 76-91) when combining LUS and PCT, and 95% (95% CI: 90-98) and 41% (95% CI: 31-52) when combining CXR and PCT. The positive predictive value for LUS and PCT was 88% (95% C:I 79%-93%) versus 68% (95% CI: 60-75) for CXR and PCT. The concordance between the final diagnosis and LUS had a kappa value of 0.69 (95% CI: 0.62-0.75) versus 0.34 (95% CI: 0.21-0.45) for CXR, (p < 0.001).

CONCLUSIONS

The combination of LUS and PCT presented a better accuracy for bacterial pneumonia diagnosis than combining CXR and PCT. Therefore, its implementation could be a reliable tool for pneumonia diagnosis in critically ill children.

CON: Procalcitonin does not have clinical utility in children with community-acquired pneumonia

Most clinical studies supporting procalcitonin (PCT)-guided management of lower respiratory tract infections have been performed in adults. There is a paucity of studies evaluating the clinical impact of PCT use in children and limited data informing age-appropriate PCT cut-offs; diagnostic accuracy in immunocompromised children; patient subgroups most likely to benefit from PCT testing; whether PCT adds value beyond available rapid molecular viral diagnostics; and optimal implementation strategies for PCT-guided treatment. At the present time there is little evidence to support routine use of PCT to aid management of paediatric pneumonia.

Systematic Review and Meta-Analysis of Diagnostic Biomarkers for Pediatric Pneumonia

BACKGROUND

Pneumonia causes significant morbidity and mortality in children worldwide, especially in resource-poor settings. Accurate identification of bacterial etiology leads to timely antibiotic initiation, minimizing overuse, and development of resistance. Host biomarkers may improve diagnostic sensitivity and specificity. We assessed the ability of biomarkers to correctly identify bacterial pneumonia in children who present with respiratory distress.

METHODS

A librarian-directed search was conducted of MEDLINE, EMBASE, CENTRAL, Global Health, the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov to May 2020 with no language restriction. Included studies compared a diagnostic biomarker in children with bacterial pneumonia to those with nonbacterial respiratory distress.

RESULTS

There were 31 observational studies of 23 different biomarkers. C-reactive protein (CRP), procalcitonin (PCT), white blood cell (WBC) count, and erythrocyte sedimentation rate (ESR) were the biomarkers with sufficient data for meta-analysis. Meta-analysis revealed that CRP and PCT best differentiated bacterial from viral pneumonia with CRP summary AUROC (area under the receiver operating characteristic curve) 0.71 (0.69-0.73), Youden index 53 mg/L, sensitivity 0.70 (0.68-0.78), and specificity 0.64 (0.58-0.68) and PCT summary AUROC 0.70 (0.67-0.74), Youden index 0.59 ng/mL, sensitivity 0.69 (0.65-0.77), and specificity 0.64 (0.60-0.68). WBC and ESR did not perform as well. Nineteen other inflammatory and immunologic biomarkers were identified including CRP/mean platelet value, neutrophil/leukocyte ratio, interleukin 6, and interferon-alpha, with sensitivities from 60% to 85% and specificities from 76% to 83%.

CONCLUSION

CRP and PCT performed better than WBC and ESR but had suboptimal sensitivity. Some less well-studied novel biomarkers appear to have promise particularly in combination.

LncRNA RP11-248E9.5 and RP11-456D7.1 are Valuable for the Diagnosis of Childhood Pneumonia

Background

Pneumonia is a common infection of the lung parenchyma in children, and early and accurate diagnosis of childhood pneumonia (CP) is important for implementing appropriate preventive and treatment strategies. This study aimed to evaluate the diagnostic value of the combination of long non-coding RNA (lncRNA) RP11-248E9.5, RP11-456D7.1, c-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) in CP.

Patients and Methods

A total of 50 healthy children (HC) and 100 CP patients were enrolled. The serum expression of RP11-248e9.5 and RP11-456d7.1 was detected by qRT-PCR. The white blood cell (WBC), hemoglobin (HB), platelet (PLT), neutrophil, and lymphocyte were analyzed by automated hematology analyzer. The serum levels of CRP and procalcitonin (PCT) were analyzed by automatic biochemical analyzer. The receiver operating characteristic (ROC) curves were applied to evaluate the diagnostic value in CP.

Results

The NLR and PLR, expression of RP11-248E9.5 and RP11-456D7.1, and serum levels of CRP and PCT were significantly higher in the CP group than those in the HC group. Both RP11-248E9.5 (AUC, 0.86; sensitivity, 84%; specificity, 78%) and RP11-456D7.1 (AUC, 0.89; sensitivity, 79%; specificity, 92%) exhibited certain diagnostic value in CP. The diagnostic values of PCT, CRP, NLR and PLR in CP were limited by low sensitivity (≤ 71%). The combination of multiple indicators improved the diagnostic value. The combination of RP11-248E9.5, RP11-456D7.1, CRP, NLR, and PLR had the best diagnostic value in CP (AUC, 0.992; Sensitivity, 0.97; Specificity, 0.99).

Conclusion

The combination of RP11-248E9.5, RP11-456D7.1, CRP, NLR, and PLR was a potential diagnostic strategy for CP.

Prospective Observational Study to Determine Kinetics of Procalcitonin in Hospitalized Children Receiving Antibiotic Therapy for Non-Critical Acute Bacterial Infections

INTRODUCTION

The kinetics of procalcitonin in pediatric patients with non-critical acute bacterial infections receiving appropriate antibiotic therapy are not well described.

METHODS

We performed a single-center, prospective observational pilot study of children admitted to a tertiary care children's hospital who were receiving antibiotics for treatment of a non-critical acute bacterial infection, and we prospectively measured serial procalcitonin levels daily for 4 days during hospitalization.

RESULTS

Among the 46 children with baseline procalcitonin levels enrolled in the study, procalcitonin kinetics followed a half-life of approximately 24 h in most patients. Procalcitonin declined faster than C-reactive protein over the first 48 h of appropriate antibiotic treatment. There was variation in biomarker levels among participants with the same infection type, especially in participants with bacteremia, musculoskeletal infection and skin/soft tissue infection.

CONCLUSION

Utility of procalcitonin as a biomarker to follow every 24-48 h in non-critically ill children receiving antibiotic therapy for bacterial infections as an objective measure of clinical improvement is promising.