PB0591 - Differences in Types of Thromboses and Risk Factors in Males versus Females in Adolescent Thromboembolism in the Throm-PED Registry

Background: Adolescents are at heightened risk for thromboembolism (TE), likely due to diagnostic/therapeutic advances, and unique health challenges. Varying risk factors in females compared to males (e.g., estrogen, autoimmune disorders/antiphospholipid syndrome) may result in differences in prevalence, and TE types, which in turn can lead to differences in treatment choices, outcome and complications. Few studies have evaluated sex-based differences in TE and no study has addressed the impact of sex in adolescent TE.

Aims: Evaluation of sex-based differences in adolescent TE characteristics and management.

Methods: The Throm-PED registry is an international, multicenter, prospective registry of the International Pediatric Thrombosis Network (IPTN). Following data prospectively collected in Throm-PED registry (overall-since 2019; specific adolescent TE protocol-since 2021) were reviewed: age at diagnosis, sex, TE type, location, risk factors, treatment.

Results: Data were analyzed for 776 adolescents with TE, M-360 (46%), F-416 (54%), median age 15 years (range-10-21 years) in both sexes (Table 1,2).
There was statistically significant greater prevalence of arterial thromboses overall, and intracranial venous, intracardiac, and aortic thromboses in males, and venous TE overall, and pulmonary embolism in females. For risk factors, congenital heart disease, surgery, and previous thrombotic event in males and oral contraceptives, obesity, antiphospholipid syndrome, and autoimmune disorders in females, were more prevalent which were statistically significant. Therapeutic modalities were similar in both.

Conclusion(s): Sex-based differences appear to impact adolescent TE characteristics with higher female prevalence as noted in our study. Increased prevalence of congenital heart disease may explain the increased prevalence of arterial/intracardiac/aortic thromboses in males. Risk factors with higher prevalence in females including estrogen therapy, autoimmune disorders, antiphospholipid syndrome and obesity might have contributed to increased prevalence of venous TE/pulmonary embolism when compared to males. Future analysis with continued follow-up we hope will shed light on the sex-based differences in TE outcome and complications.