Acute pulmonary embolism in children and adolescents in the USA (2016 and 2019): a nationwide retrospective cohort study

Background: 

Epidemiological data on acute pulmonary embolism among children and adolescents are sparse and only date back to the 2000s. We aimed to establish annual estimates and age-stratified and sex-stratified indicators of acute pulmonary embolism among children and adolescents aged 0–19 years. 

Methods: 

We did a retrospective, nationwide, patient-level analysis of the Kids’ Inpatient Database, including 5733 patients with acute pulmonary embolism aged 0–19 years admitted to hospital in the USA in 2016 and 2019. The database includes data of all children admitted to hospital during the 2 years available. We also accessed the US Multiple Cause of Death database and population data from the US Census Bureau for the same 2 years. We estimated the incidence, mortality, case fatality, and proportional mortality rates, provided data on the annual pulmonary embolism burden, and provided data on clinical events recorded during hospitalisation. 

Findings: 

In the years 2016 and 2019, 5733 patients (3353 [58.5%] female and 2380 [41.5%] male) were admitted to hospital with acute pulmonary embolism as the primary diagnosis or a concomitant diagnosis. The annual incidence of acute pulmonary embolism was 3·5 (95% CI 3·4–3·6) per 100 000 people. Two peaks in the incidence rate were observed—one in infants younger than 1 year and one in adolescents aged 15–19 years. The in-hospital case fatality rate was 4·5% (4·0–5·1). The crude odds ratio for in-hospital death among patients with (vs without) acute pulmonary embolism was 9·3 (7·9–10·9). The association between acute pulmonary embolism and death persisted across different multivariable models. Patients with acute pulmonary embolism with high-risk (vs no high-risk) features had the highest risk of death: 25·3% (20·6–30·5) among patients aged 0–9 years and 13·9% (11·9–16·2) among patients aged 10–19 years. In patients without high-risk features, risk of death was 4·9% (3·1–7·6) among patients aged 0–9 years and 0·7% (0·5–1·0) among patients aged 10–19 years. The risk of intracranial bleeding was also highest in the presence of pulmonary embolism with high-risk features: 8·1% (5·5–11·7) among patients aged 0–9 years and 3·6% (2·6–4·9) among patients aged 10–19 years. In patients without high-risk features, the risk of intracranial bleeding was 2·5% (1·3–4·6) among those aged 0–9 years and 0·5% (0·3–0·8) in those aged 10–19 years. Reperfusion treatments beyond systemic thrombolysis were rarely used among children and adolescents with acute pulmonary embolism. 

Interpretation: 

Acute pulmonary embolism is rare during childhood and adolescence. The high pulmonary embolism-related fatality among specific subgroups of patients can be interpreted in the context of severe comorbidities and pulmonary embolism events with high-risk features.