Incidence Trends and Mortality from Childhood Venous Thromboembolism: A Population-Based Cohort Study

Objective: To determine the incidence, incidence trend, and mortality of venous thromboembolism (VTE) in a general pediatric population during an 11-year period.

Study Design: The administrative health care databases of the province of Québec, Canada were used to identify all children (ages 1-17 years inclusive) diagnosed with incident VTE between January 1, 1994 and December 31, 2004. The incidence rate and trend over the 11-year study period were then analyzed.

Results: In total, 487 incident cases of pediatric VTE were documented. The age-standardized incidence rate was 0.29 VTE per 10 000 person-years (95% CI 0.26-0.31). Girls had a statistically significant higher incidence rate (per 10 000 person-years) than boys, 0.37 and 0.21 per 10 000 person-years, respectively, with an incidence rate ratio comparing females with males, adjusted for age group of 1.75 (95% CI 1.46-2.10). Trend analysis illustrated no statistically significant change in the age-standardized incidence rates. Overall all-cause mortality was 11.4 per 1000 children-years (95% CI 8.1-16.1).

Conclusions: Pediatric VTE is frequent, although its incidence is stable over time and all-cause mortality is lower than previously reported. Future studies that address possible sex and age group differences in the incidence of pediatric VTE are needed to help determine effective primary thromboprophylaxis strategies in children at high risk for VTE.