Derivation and Validation of a Clinical Rule to Detect Bacteremia Versus Contaminants in Positive Pediatric Blood Cultures: A Retrospective Cohort Study
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Published on: October 15, 2014
Jocelyn Gravel1, Charlotte Grandjean-Blanchet1, Alino Demean Loghin2
1Department of Pediatric Emergency Medicine CHU Sainte-Justine, Université de Montréal, Montréal, Montréal, QC, Canada.
Insights
A new clinical decision rule accurately identifies bacteremia in children with positive blood cultures, reducing unnecessary hospitalizations and improving resource allocation in pediatric emergency departments.
Area of Science:
- Pediatric Emergency Medicine
- Infectious Diseases
- Clinical Decision Support
Background:
- Contamination of blood cultures is common in pediatric emergency departments, leading to unnecessary treatments.
- Distinguishing true bacteremia from contaminants is crucial for appropriate patient management.
Purpose of the Study:
- To derive and validate a clinical decision rule to differentiate bacteremia from contaminants in children with positive blood cultures.
- To improve the accuracy of diagnosing bacteremia in pediatric emergency settings.
Main Methods:
- Utilized two cohorts of children with positive blood cultures for derivation and validation.
- Employed Classification and Regression Tree models to develop a highly sensitive clinical decision rule.
- Assessed rule validity using sensitivity and specificity, and clinical utility by comparing it to physician management.
Main Results:
- The derived clinical decision rule demonstrated 99% sensitivity and 60% specificity in the validation cohort.
- The rule classifies children into high, moderate, and low-risk categories based on four criteria.
- Application of the rule could reduce hospitalizations by identifying children with low risk of bacteremia.
Conclusions:
- A highly sensitive clinical decision rule for identifying pediatric bacteremia from positive blood cultures has been developed.
- Implementation of this rule has the potential to significantly optimize health system resource utilization.
- This tool aids in accurate bacteremia diagnosis, impacting patient care and resource management.
Study Objectives:
Fifty percent of positive blood cultures in the pediatric emergency department (ED) are contaminants. We derived and validated a clinical decision rule discriminating bacteremia from contaminants among children seen in the ED with a positive blood culture.
Methods:
We used 2 cohorts of children with positive blood cultures from a Canadian pediatric ED in 2018 to 2022 (derivation) and 2023 to 2024 (validation). The primary outcome was bacteremia. Potential predictors of bacteremia were derived from a literature review and experts' consensus. We used Classification and Regression Tree models to derive a highly sensitive clinical decision rule. The validity was assessed by measuring the proportion of children with true bacteremia classified at high or moderate risk by the clinical decision rule (sensitivity) and the proportion of contaminants classified at low risk (specificity). The clinical utility was measured by comparing the clinical decision rule to the treating physician's management.
Results:
A total of 747 children, including 368 cases of bacteremia were included in the derivation (total 574; 285 bacteremia) and validation (total 173; 83 bacteremia) cohorts. The clinical decision rule classifies children into 3 categories (high, moderate, and low risk) based on 4 criteria. It demonstrated a sensitivity of 99% (95% confidence interval [CI] 94 to 100) and a specificity of 60% (95% CI 50 to 70) in the validation cohort. Using the clinical decision rule among the 43 children initially discharged in the validation cohort would decrease the number of hospitalizations from 34 to 21 without missing a true bacteremia.
Conclusion:
We created a very sensitive clinical decision rule to identify bacteremia in children with positive blood culture. Adopting this clinical decision rule could significantly impact health system resources.
