Utility of procalcitonin levels in identifying bacterial infections in children with and without COVID-19

Rationale: Elevated procalcitonin levels are associated with increased rates of bacterial infection in children. Observational studies have reported high levels of procalcitonin in COVID-19 and correlated procalcitonin level with illness severity. Data on rates of bacterial coinfections in COVID-19 are sparse;small studies suggest a low coinfection rate. We aim to quantify the positive predictive value (PPV) of procalcitonin in identifying bacterial infection in pediatric patients with and without COVID-19. Methods: A retrospective chart review was performed of 215 pediatric patients age 1 month to 21 years admitted to our tertiary children's hospital between February 1, 2013 and July 15, 2020 who had procalcitonin levels measured within 48 hours of admission. Confirmed bacterial infection was defined as positive blood, urine, or CSF culture, positive endotracheal/sputum culture with significant leukocytosis on gram stain, or CXR consistent with pneumonia. Contaminated blood cultures were excluded. Suspected bacterial infection was defined as either confirmed bacterial infection or administration of therapeutic antibiotics for >48 hours. Results: Of the 215 patients, 73 were PCR and/or antibody positive for SARS-CoV-2 (53% admitted to PICU, 29% required vasoactive medications) and 142 had alternative diagnoses (32% admitted to PICU, 9% required vasoactive medications). Median procalcitonin level was 1.28ng/mL in the COVID-19 cohort and 0.37ng/mL in the control cohort. There were 10 suspected and 5 confirmed bacterial infections in the COVID-19 cohort and 69 suspected and 44 confirmed bacterial infections in the control cohort. Procalcitonin was greater than 1ng/mL in 39 (53%) of COVID-19 subjects and 44 (31%) of control subjects. PPV of procalcitonin level over 1ng/mL for identifying suspected bacterial infection in the COVID-19 cohort was 10% (CI 1-20%) and in the control cohort was 75% (CI 62%-88%). PPV of procalcitonin level over 1ng/mL for identifying confirmed bacterial infection in the COVID-19 cohort was 3% (CI 0%-8%) and in the control cohort was 55% (CI 40%-69%). Conclusions: Our retrospective review demonstrated a low PPV of elevated procalcitonin level above the established threshold of 1ng/mL in identifying either culture-confirmed or suspected bacterial infection in pediatric patients hospitalized with COVID-19. Despite 29% of the COVID-19 cohort requiring vasoactive support, indicating a high pretest probability of bacterial sepsis, procalcitonin performed poorly as a marker of bacterial infection. Our results suggest that COVID-19 infection is associated with an elevated procalcitonin level independent of presence of bacterial infection. Given the importance of antibiotic stewardship, alternative means of identifying bacterial coinfection in COVID-19 are needed.

Characteristics and risk factors associated with critical illness in pediatric COVID-19

INTRODUCTION: Little is known regarding the course and severity of pediatric COVID-19. We describe critical illness in pediatric patients with PCR+ SARS-CoV2 infection and identify factors associated with PICU admission and organ dysfunction. METHODS: This is a retrospective chart review of 77 pediatric patients age 1 day to 21 years admitted to two New York City pediatric hospitals within the Northwell Health system between February 1 and April 24, 2020 with PCR+ SARS-CoV-2. Descriptive statistics were used to describe the hospital course and laboratory results and bivariate comparisons were performed on variables to determine differences. RESULTS: Forty-seven patients (61%) were admitted to the general pediatric floor and thirty (39%) to the PICU. The majority (97%, n=68) survived to discharge, 1.3% (n=1) remain admitted, and one (1.3%) died. Of PICU patients, 46.7% experienced significant organ dysfunction (pSOFA>=2) during admission. Patients aged 12 years or greater were more likely to be admitted to a PICU compared to younger patients (p=0.015). Presence of an underlying comorbidity was not associated with need for PICU admission (p=0.23) or organ dysfunction (p=0.87). Initial white blood cell count (WBC), platelet count, and ferritin were not associated with need for PICU admission. Initial C-reactive protein was associated with both need for PICU admission (p=0.005) and presence of organ dysfunction (p=0.001). Initial WBC was associated with organ dysfunction (p=0.034). Presenting thrombocytopenia was associated with organ dysfunction (p=0.003). Common indications for PICU admission included hypoxia (50%), hemodynamic instability (20%), diabetic ketoacidosis (6.7%), mediastinal mass (6.7%), apnea (6.7%), acute chest syndrome (6.7%), and cardiac dysfunction (6.7%). CONCLUSIONS: Need for PICU admission in COVID-19 was associated with age over 12 years and elevated initial CRP. Organ dysfunction was associated with elevated admission CRP and WBC and decreased platelet count. These factors may be useful in determining risk for critical illness and organ dysfunction in pediatric COVID-19.