Prevalence of Bleeding Disorders

The most common inherited hematologic bleeding disorders are von Willebrand disease (vWD) and Hemophilia. vWD is most common, affecting approximately 1 in every 100 people, but most individuals experience only mild symptoms such as a tendency for increased nose bleeds or frequent bruising. Men and women are affected equally, but women are more likely to experience symptoms of vWD because of the increased bleeding it causes during their menstrual periods, during pregnancy, and after childbirth.^18,19In addition, the Centers for Disease Control and Prevention estimates it takes a woman an average of 16 years from onset of symptoms to be diagnosed with vWD.²⁰

There are two main types of hemophilia, consisting of A and B. Hemophilia is caused by an X-linked genetic defect causing loss of function or reduced effectiveness of coagulation factor VIII in hemophilia A and factor IX in hemophilia B. Hemophilia A is the most common of the two types and is classified as either mild, moderate, or severe based on coagulation factor activity and clinical bleeding phenotype. Hemophilia A patients with symptomatic bleeding are typically men, but women can also be affected by clinically significant bleeding. Recognizing hemophilia in women remains a major challenge due to past assumptions that women are not affected, even “carriers” where the FVIII activity is normal have abnormal bleeding.²¹Figure 2 illustrates the current prevalence of bleeding disorders in the United States. As reported by the National Bleeding Disorders Foundation, there are between 30,000-33,000 people living with hemophilia in the United States. Hemophilia A affects 1 in 5,000 male births and approximately 400 babies are born with hemophilia A annually.²²

In the United States, a rare disease or disorder is defined as one that affects fewer than 200,000 people. By this definition, hemophilia A and B, and the less-common factor deficiencies are all classified as rare disorders.²³