Pediatric Venous and Arterial Noncerebral Thromboembolism in Denmark: A Nationwide Population-Based Study

Objective To assess the incidence rate (IR), changes in IR over time, risk factors, treatment, and outcomes of pediatric noncerebral thromboembolism (TE). Study design The study included all patients aged 0 to 18 years diagnosed with first-ever noncerebral venous thromboembolism (VTE) and/or arterial TE in Denmark between 1994 and 2006. Patients were identified in national registries, followed by validation of diagnoses by medical records review. Results We confirmed 331 cases of VTE and 46 cases of arterial TE during 15.8 million person-years of observation, with corresponding IRs of 2.09 and 0.29 per 100 000 person-years. The IR peaked in infancy (age <1 year) for both VTE and arterial TE, with an additional peak among adolescents (age 15 to 18 years) for VTE. Boys predominated in IR of VTE in infancy, whereas girls did so in adolescence (P < .01). The IRs of VTE and arterial TE remained stable during the study period, but with an trend toward increasing VTE in 2001 to 2006 (P = .064). Underlying diseases/external triggers were present in 86.6% of the patients, and thrombophilia was present in 47.9% of the VTE cases. All-cause and TE-related 30-day case fatalities were 4.0% and 1.6%, respectively. Conclusions We found age- and sex-related disparities in the IRs of pediatric VTE and arterial TE, but insignificant changes in IR from 1994 to 2006. (J Pediatr 2011;159:663-9).