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Information for People with Bleeding Disorders

Mother and child with counselor

The Universal Data Collection (UDC) system was created because people with bleeding disorders demonstrated to Congress the need for more information in order to improve care for those affected. The project is being carried out with the help of federally funded hemophilia treatment centers (HTCs) in the United States. Since the project began in 1998, more than 24,000 people with bleeding disorders have participated in the activities of the UDC system. More than 80% of all people with hemophilia cared for at these centers are in the UDC system.

Participating in UDC

The UDC system is open to people of all ages with bleeding disorders, including babies. People that have a bleeding disorder and receive care at a federally funded HTC should talk to a doctor or nurse at their HTC to enroll. To find the location of the HTC nearest you, go to the HTC Directory.

It’s Your Choice

The decision to take part in the UDC system is totally up to you. You can choose whether or not to take part. Choosing not to take part in the UDC system will in no way affect the care that you receive at your HTC. To help you decide if participation in the UDC system is right for you, talk to the staff at your HTC. Before you can take part in the UDC system, you will be asked to read a form that describes the project and then to sign it if you agree to take part.

You can decide to stop being in the study at any time. Deciding to withdraw will not result in any change in your medical care.


Federal privacy laws require your HTC and CDC to protect your information. You will be assigned a unique identification (ID) number. Your privacy is protected by using this number on all forms and blood samples sent to CDC. Only your HTC can match your number to your name. Your ID number will never be given to hospital, insurance company, employer, or school, no matter what. Not even a court of law can make your HTC give out this information. CDC will never receive your name and will not be able to link you to your data in any way.

Why it’s Important to Participate – Your Data Counts!

People with bleeding disorders represent a very small percentage of the overall population. To conduct research that leads to improved care, it is necessary to collect data from as many patients as possible. Your data are critical to help researchers make new discoveries.

Some possible benefits of taking part in the UDC system include:

  • Free testing for HIV and hepatitis A, hepatitis B, and hepatitis C (participants 2 years of age or older) and confidential results.
  • A sense of pride from contributing information that could lead to better treatments and improved health.
  • Faster investigation of potential blood safety threats.
Healthcare provider checking range of motion

What to Expect

If you participate in UDC, the health information collected from you depends on the type of bleeding disorder you have, your age, and your sex. For example, based on your disorder, you might be asked to provide just information, or also to have certain procedures (such as blood tests and joint measurements).

During a routine care visit to an HTC, the staff will look over your medical record and ask you some general questions about your:

  • Diagnosis
  • Bleeding history
  • Use of treatment products
  • Ability to attend school or work
  • Overall activity level
  • Joint range of motion
  • Blood samples
  • Quality of life

Depending on the type of disorder you have and your age, the HTC staff might:

  • Collect a sample of your blood for virus testing. A small amount of the sample then will be stored or “banked” for possible use in future blood safety studies.
  • Measure how well your joints (for example, your hips, knees, shoulders, elbows, and ankles) move to see how your joint health changes over time.
  • Test your blood to check your iron level.
  • Ask you to fill out a quality-of-life survey if you are at least 14 years of age to gather information about how you have been feeling and how your disorder affects your school, work, and social life.

Your Data at Work

The information collected through the UDC system is used to help doctors, patients, and scientists understand how bleeding disorders affect patients and how best to provide treatments that are both safe and work well.

Through the UDC system, researchers want to:

  • Learn how many people have complications of bleeding disorders and how severely they are affected.
  • Study how different treatments affect patient health.
  • Monitor the safety of blood products used to control bleeding.
  • Identify issues that require further research.

This information will be used to inform doctors and others who provide your care how they might be able to prevent complications and improve that care.

Important Findings

This study is looking at trends and changes over time, so the analyses are just beginning. A few of the findings so far are:

  • Youth with hemophilia are just as likely as youth among the general population to be overweight.
  • Youth with hemophilia who are overweight are more likely to have decreased joint mobility than those who are not overweight.
  • Joint infections are a rare complication of hemophilia, but they are more common among people with hemophilia than among those without the condition. Infections happen mainly in problem joints that bleed frequently or have undergone joint surgery.
  • No new infections of hepatitis A, hepatitis B, hepatitis C, or HIV have been linked to blood products used to treat bleeding disorders.
  • Among deaths of people with bleeding disorders reported to CDC during the period 1997–2007, the most common causes were related to HIV infection (19%) and liver disease (22%) probably related to hepatitis C infection. Both of these infections could be transmitted by hemophilia treatment products before 1986. Hemophilia-related (bleeding) causes of death were less common (12%).
  • The most common sites of bleeding among babies with hemophilia are the circumcision site and the head. Bleeding inside the head (intracranial hemorrhage) is a very serious complication and can result in long-term effects such as seizures and learning disabilities.
  • The rate of new inhibitors (antibodies to treatment products) among previously treated patients with hemophilia is very low. However, more study is needed to determine why they occur because an inhibitor makes treating hemophilia more complicated and expensive.

For More Information

Talk to the nurse, doctor, or social worker at your HTC if you would like to know more about the UDC system or have any questions.