Data and Statistics on Hemophilia

Key findings

Incidence and prevalence1

• The exact number of people living with hemophilia in the United States is not known. A CDC study that used data collected on patients receiving care in federally funded hemophilia treatment centers during the period 2012–2018 estimated that as many as 33,000 males in the United States are living with the disorder.
• Hemophilia A (low levels of clotting factor VIII [8]) is three to four times as common as hemophilia B (low levels of clotting factor IX [9]).
• Among all males with hemophilia, just over 4 in 10 have the severe form of the disorder.

Diagnosis2

• In the United States, most people with hemophilia are diagnosed at a very young age. Based on CDC data, the median age at diagnosis is 36 months for people with mild hemophilia, 8 months for those with moderate hemophilia, and 1 month for those with severe hemophilia.
• In about two thirds of cases diagnosed as babies, there is a family history of hemophilia. The diagnosis of hemophilia is made using a special blood test and most babies can be tested soon after birth. Sometimes prenatal genetic testing is done to diagnose hemophilia before birth.
• For the one third of babies born with hemophilia in families with no known history of hemophilia, the diagnosis is made when an unusual bleeding event occurs.

Many children with hemophilia are diagnosed before they are 2 years old.

Complications

Bleeding

• In both hemophilia A and B, the blood does not clot properly, which can lead to spontaneous internal bleeding (bleeding that occurs for no known reason) as well as excessive bleeding after injuries or surgery.34
• Hemophilia can cause repeated bleeding within joints that can lead to chronic joint disease, pain, and mobility limitations. Hemophilia also poses a risk for bleeding in the head and sometimes in the brain which can cause long term problems, such as seizures and paralysis. Death can occur if the bleeding cannot be stopped.34
• The extent of bleeding into the joints and other complications varies by the severity of the hemophilia (which is defined based on how low the level of clotting factors is in the blood).34
• In addition to hemophilia severity, being overweight, as measured by body mass index (BMI), is strongly associated with joint mobility limitations.34
• Because hemophilia is inherited through mutations to genes located on the X chromosome, bleeding symptoms in females with hemophilia are usually milder than symptoms in males with hemophilia. Nonetheless, females with hemophilia A or hemophilia B have been found to have reduced joint range of motion compared with females with no bleeding disorder.5
• The best way to treat hemophilia, is to replace the missing blood clotting factor so that the blood can clot properly. This is usually done by infusing (injecting into a vein) commercially prepared factor concentrates. Episodic care is used to stop a patient's bleeding episodes; prophylactic care is used to prevent bleeding episodes from occurring.
• A CDC-sponsored randomized clinical trial found that children who were treated on a regular basis to prevent bleeding (prophylactic care) had less evidence of joint damage by 6 years of age than did those who were treated only after a bleed had started (episodic care).6

Inhibitors to treatment products

• About 1 in 5 people with hemophilia A and about 3 in 100 people with hemophilia B will develop an antibody—called an inhibitor—to the treatment products (called factor concentrates) used to stop or prevent their bleeding episodes.78
• People with hemophilia who develop an inhibitor are twice as likely to be hospitalized for a bleeding complication, and they are at increased risk of death.9
• A 6-year study of patients in 17 US hemophilia treatment centers found that all patients with hemophilia can be at risk for an inhibitor and regular screening for an inhibitor is important.10

Other health problems11

• As more people with hemophilia are living longer, it's important to know what other health problems are affecting the aging hemophilia community to better understand their healthcare needs. A CDC study evaluated the prevalence of health conditions in more than 2,200 men with hemophilia who were aged 45 years or older in 2013 to 2021.
• In comparison with men in the general US population, men with hemophilia had
  • Lower prevalence of coronary artery disease, stroke, heart attack, and leukemia, and
  • Higher prevalence of anxiety, depression, and obesity.
• Additionally, nearly 3 in 4 men with hemophilia had a history of prior hepatitis C virus (HCV) infection, and about 1 in 4 had a history of human immunodeficiency virus (HIV) infection.
• Men with hemophilia who had a history of HIV or HCV infection had a higher prevalence of chronic kidney disease, liver cancer, anxiety, and depression than those without infections.