Clinical Spectrum of Hereditary Hemorrhagic Telangiectasia: Data from the Comprehensive HHT Outcomes Registry of the US (CHORUS)

Hereditary hemorrhagic telangiectasia (HHT), an autosomal dominant vasculopathy afflicting 1 in 5000 individuals, is the second-most-common inherited bleeding disorder worldwide. Despite this prevalence, comprehensive data on disease manifestations and complications remain limited. To address this gap, the U.S. Congress allocated funding leading to the Comprehensive HHT Outcomes Registry of the United States (CHORUS; NCT06259292), a prospective, 15-center longitudinal registry enrolling unselected patients with confirmed HHT. In this initial report, we describe findings from the first 600 participants, with a median (range) age of 53 (0-88) years and 60% female. Despite most participants developing typical HHT manifestations by age 13, the majority (63%) were not diagnosed until mid-to-late adulthood. Recurrent spontaneous epistaxis occurred in 95% of participants, chronic gastrointestinal bleeding in 30%, and heavy menstrual bleeding in 35% of post-menarche females, together resulting in moderate-to-severe mucosal bleeding in 76%. Iron deficiency and/or anemia were diagnosed in 68%, with 41% requiring intravenous iron and 25% requiring red cell transfusions. Serious complications of solid-organ arteriovenous malformations were frequent, including intracranial hemorrhage (3%), pulmonary hemorrhage (2%), venous thromboembolism (7%), arterial thromboembolism (11%), heart failure (7%), and pulmonary hypertension (7%). This data from CHORUS, the first national registry of its kind, provides reliable, real-world estimates of the incidence, prevalence and severity of numerous HHT manifestations and complications. HHT has a high burden of moderate-to-severe bleeding, anemia, thrombosis, and major neurologic and cardiopulmonary complications. There is a mean interval between first symptoms and diagnosis of over two decades, during which substantial serious, preventable HHT morbidity, including early intracranial hemorrhage, may occur.