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One of the major challenges facing scientists who work on rare disorders, such as hemophilia, is the lack of uniform health data. To address this issue and to advance health research, CDC created a national public health surveillance project called the Universal Data Collection (UDC) system. UDC was carried out in collaboration with federally funded hemophilia treatment centers (HTCs) in the United States and its territories.

During the system's operation from 1998-2011, about 27,000 people with bleeding disorders have contributed their health data by participating in the UDC program. More than 80% of all people with hemophilia who receive cared at HTCs during that period participated in the study.

UDC Data Reports

UDC data and reports are available to HTC staff. Staff at each HTC can download electronic files containing UDC data collected from participants at their HTC. In addition, national and regional reports are available to the public on CDC’s website.

UDC Data Reports »

Important Findings

Several articles about studies that used UDC data have been published. A few of the findings so far are:

  • Youth with hemophilia are just as likely as youth among the general population to be overweight.1
  • Youth with hemophilia who are overweight are more likely to have decreased joint mobility than those who are not overweight.1
  • 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.2
  • No new infections of hepatitis A, hepatitis B, hepatitis C, or HIV have been linked to blood products used to treat bleeding disorders.3
  • 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 clotting factor products before 1986. Hemophilia-related (bleeding) causes of death were less common (12%).4
  • 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.5
  • The rate of new inhibitors (antibodies to clotting factor products) among previously treated patients with hemophilia is very low. However, more study is needed to determine why they occur because an 6
  • Overweight and obesity accelerates joint mobility loss in weight-bearing joints, particularly among those with severe hemophilia.7
  • Intracranial hemorrhage (ICH) occurs when there is bleeding inside the skull. The most significant risk factors for an ICH are (1) the presence of an inhibitor (2) prior ICH (3) severe hemophilia and (4) reported head trauma. Consistent use of preventive medication can reduce the risk for ICH.8
  • Youth with severe hemophilia who obtain care annual within the United States HTC network are often insured and use preventive home treatments.9
  • Hispanic males are more likely to develop inhibitors than non-Hispanic males.10
  • Patients exposed to treatments using human blood may be exposed to certain viruses.11

Learn more about the UDC system


  1. Soucie JM, Cianfrini C, Janco RL, et al. Joint range of motion limitations among young males with hemophilia: Prevalence and risk factors. Blood 2004; 103:2467-73.
  2. Ashrani AA, Key NS, Soucie JM,Duffy N, Forsyth A, Geraghty S and the Universal Data Collection Project Investigators. Septic arthritis in males with haemophilia. Haemophilia 2008; 14:494-503.
  3. CDC. Blood Safety Monitoring Among Persons with Bleeding Disorders. MMWR January 3,2003;51(51-52);1152-54.
  4. Poster Presentation. Larsen NM et al: Mortality Among Patients Treated at Federally Funded Hemophilia Treatment Centers (HTCs). National Hemophilia Foundation Annual Meeting October 2007.
  5. Kulkarni R, Soucie JM, Lusher J, et al. Sites of initial bleeding episodes, mode of delivery and age of diagnosis in babies with haemophilia diagnosed before the age of 2 years: a report from the Centers for Disease Control and Prevention’s (CDC) Universal Data Collection (UDC) project. Haemophilia e-pub July 22, 2009.
  6. Kempton CL, Soucie JM, Abshire TC. Incidence of inhibitors in a cohort of 838 males with hemophilia A previously treated with factor VIII concentrates. J Thromb Haemostasis 2006; 4:2576-2581.
  7. Soucie JM, Wang C, Siddiqi A, Kulkarni R, Recht M, Konkle BA, Hemophilia Treatment Center Network. The longitudinal effect of body adiposity on joint mobility in young males with hemophilia A. Haemophilia 2011;17(2):196-203.
  8. Witmer C, Presley R, Kulkarni R, Soucie JM, Manno CS, Raffini L. Associations between intracranial haemorrhage and prescribed prophylaxis in a large cohort of haemophilia patients in the United States. British Journal of Haematology 2011;152(2):211-216.
  9. Baker JR, Riske B, Voutsis M, Cutter S, Presley R. Insurance, Home Therapy, and Prophylaxis in U.S. Youth with Severe Hemophilia. AJPM 2011; 41:S338-S345.
  10. Carpenter SL, Soucie JM, Sterner S, Presley R, Hemophilia Treatment Center Network (HTCN) Investigators. Increased prevalence of inhibitors in Hispanic patients with severe haemophilia A enrolled in the Universal Data Collection database. Haemophilia 2012;18(3)[May]:e260-e265.
  11. Soucie JM, De Staercke C, Monahan PE, Recht M, Chitlur MB, Gruppo R, Hooper WC, Kessler C, Kulkarni R, Manco-Johnson MJ, Powell J, Pyle M, Riske B, Sabio H, Trimble S & the U.S. Hemophilia Treatment Center Network. Evidence for the Transmission of Parvovirus B19 in Patients with Bleeding Disorders Treated with Plasma-derived Factor Concentrates in the Era of Nucleic Acid Test (NAT) Screening. Transfusion 2013; 53(5)[May] 2013: 1143–1144 [epublished 24 SEP 2012 DOI: 10.1111/j.1537-2995.2012.03907.x].