Burden and management of venous thromboembolism in children and adolescents (2004-2023): a Swiss nationwide epidemiological study.

Epidemiological data on venous thromboembolism (VTE) in children and adolescents is sparse and available primarily for the USA. In Europe, the burden and management of VTE have rarely been subjects of nationwide analyses.We conducted a nationwide, retrospective, patient-level analysis of the Swiss medical statistics an administrative data collection including 1961 hospitalizations (1653 incident events) with VTE aged 19 or younger between 2004 and 2023. We estimated the disease-specific incidence rate, in-hospital case fatality rates, length of stay (LOS), and related admission to the intensive care unit (ICU). Furthermore, we evaluated therapeutic procedures.The incidence rate of incident VTE-related hospitalizations was 4.9 (95%CI 4.7; 5.2) per 100,000 children and adolescents per year. The in-hospital case fatality rate was 4.0% (95%CI 3.2; 5.0); the median LOS was 8 (Q1-Q3 4-24) days. Systemic thrombolysis, catheter-directed treatment, and inferior vena cava filters were used in less than 15% of patients. Among patients receiving systemic thrombolysis, the in-hospital case fatality rate was 19.4% (95%CI 12.6; 28.5), whereas patients managed with catheter-directed treatment had a rate of 8.0% (95%CI 3.2; 18.8). 39.3% of patients were admitted to ICU. Age- and sex-specific differences in incidence rate, proportion of hospital admissions, and in-hospital case fatality rate were observed, particularly among infants aged < 1 year and adolescents aged 15-19 years. CONCLUSION: VTE among children and adolescents is rare with age- and sex-specific differences in incidence. Patients who underwent advanced treatment strategies presented with a substantial risk of in-hospital death despite treatment, especially evident among patients aged 0-9 years. WHAT IS KNOWN: • Venous thromboembolism and in extension pulmonary embolism and deep vein thrombosis are rare diseases among children and adolescents. WHAT IS NEW: • We provided national estimates for measures of occurrence of venous thromboembolism from a European country. • We analyzed the management of these patients with a focus on advanced treatment strategies, providing estimates on the in-hospital fatality rate.