Sex differences in treatment strategies for pulmonary embolism in older adults: The SERIOUS-PE study of RIETE participants and US Medicare beneficiaries

Introduction: Sex differences exist in risk factors and comorbidities of older adults (aged >= 65 years) with pulmonary embolism (PE). Clinically relevant sex-based treatment disparities for PE have not been adequately addressed. The few existing show conflicting results due to small sample size (type II error) and suboptimal methods (overreliance on p-value, which may detect differences of small clinical relevance). Methods: We assessed sex differences in anticoagulation and advanced therapies for PE in older adults, utilizing data from Registro Informatizado Enfermedad TromboEmbolica (RIETE), a large PE registry with predominant participation from Europe, and data from US Medicare beneficiaries. We prespecified a standardized difference (SRD) > 10% as clinically relevant. RIETE included 33,462 (57.7% female) and Medicare included 102,391 (55.0% female) older adults with PE. Results: In RIETE, there were no overall sex differences in the use of anticoagulation (median: 181 vs 180 days, SRD < 1%), fibrinolysis (SRD < 3%), thrombectomy (SRD < 2%), or inferior vena cava (IVC) filters (SRD: 4.4%). However, fibrinolytic therapy (systemic or catheter-based) was less often used in female than male patients with intermediate-risk PE (8.0% vs 12.1%, SRD: 13.6%). No sex differences were noted with advanced PE therapies in Medicare beneficiaries. In unadjusted analyses, fibrinolysis and IVC filter placement were more frequent in Medicare than RIETE participants regardless of sex (p < 0.001). Conclusion: In a predominantly European PE registry and a US study of older adults, there were no overall sex differences in anticoagulation patterns or advanced therapy utilization. Future studies should determine if sex disparities in fibrinolytic therapy for intermediate-risk PE and greater use of advanced therapies in US older adults correlate with clinical outcomes.