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.