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Eligible diagnoses include hemophilia A, hemophilia B, Von Willebrand disease (VWD), other rare clotting factor deficiencies or fibrinolytic regulator deficiencies, hereditary/functional platelet disorders, connective tissue disorders, unspecified bleeding disorders, and venous thromboembolism (VTE).

Included within the HTC PP are participants with the aforementioned diagnoses, 89 years of age or younger, who receive care at HTCs, either in person or by telemedicine.

Data Collection

Data for the HTC PP are collected as a de-identified1 data set in compliance with the Health Insurance Portability and Accountability Act (HIPAA). The following 12 items are collected:

  1. Year of birth
  2. Sex
  3. Ethnicity (Hispanic versus non-Hispanic)
  4. Race
  5. First three digits of residence zip code
  6. Insurance status
  7. Primary bleeding disorder diagnosis
  8. Baseline factor activity
  9. Von Willebrand factor activity (vWF:RCof)
  10. Von Willebrand factor antigen level (vWF:Ag)
  11. Hepatitis C (HCV) infection status
  12. HIV infection status

HTC PP data are collected for each calendar year.2

The Registry


Persons with a bleeding disorder diagnosis who receive care at an HTC are eligible for inclusion in the data collection effort. Eligible diagnoses include hemophilia A, hemophilia B, VWD, other rare clotting factor deficiencies or fibrinolytic regulator deficiencies, and hereditary/functional platelet disorders.

CDC considers this program to be non-research public health surveillance, for which disclosure of protected health information by covered entities is authorized by Title 45, Code of Federal Regulations section 164.512(b), pursuant to the Standards for Privacy of Individually Identifiable Information promulgated by HIPAA. As such, federal regulations do not require written informed consent. Nonetheless, written authorization is sought from all participants to ensure they are informed about the project. A minority of participating institutions designated the project as research, requiring written informed consent.

Data Collection

The Registry data are collected during a participant’s routine comprehensive clinic visits. Data are collected according to guidelines and definitions detailed in surveillance manuals. Clinical information is collected using a combination of medical record abstraction and direct patient interview by HTC staff as a part of the routine clinical assessment. Information collected includes demographics (e.g., sex, race, age, insurance status), bleeding disorder diagnoses, treatments, bleeding events, related complications (e.g., inhibitor development), healthcare utilization, and presence of other health conditions. An “Initial Visit” form is completed one time only for each participant to collect historic and current clinical information. Thereafter, a “Subsequent Visit” form is completed, as often as annually3, to collect clinical information and outcomes data since the last episode of participation.

From December 1, 2013 through August 23, 2015, completed Registry “Initial Visit” paper forms were mailed to CDC and entered into a computer database. Upon entry into the database, data were examined for missing information, inconsistencies, and unusual values that possibly represented abstraction or data-entry errors. Error reports were sent to the respective HTCs, and a designated contact at each HTC used available information to resolve discrepancies and complete missing data items.

Beginning on August 24, 2015, the Registry “Initial Visit” form data have been submitted electronically using ATHN’s web-based system for electronic data collection, the ATHN Study Manager. The data are packaged into an electronic data file that is sent to CDC daily. The ATHN information infrastructure is housed at commercial data centers that meet industry standards for security and encryption. Data from individual participants and specimens are reported to CDC using a coded, unique subject identification number, as well as an HTC identification number. The subject identification number is generated randomly by a computer program, and is not derived from any personal identifiers. As a HIPAA-compliant, limited data set, no identifiers listed as direct identifiers in Section 164.514 (e) of the HIPAA Privacy Rule are sent to CDC or ATHN.

Blood Specimen Testing and Storage

Although precautions are taken to reduce the risk of contaminated blood products and UDC found no new infections of hepatitis or HIV that were linked to treatment products, there is a chance that treatment of persons with bleeding disorders may involve infusion of blood products that may be contaminated with blood-borne viruses or other agents that can cause disease. Treatment also may involve use of clotting factor products, which may pose a risk for complications, including the development of an antibody (inhibitor) to the treatment product that decreases the effectiveness of the product to stop bleeding. To monitor for these complications, participants who have used certain treatment products, including blood products, plasma-derived factor concentrates, and recombinant factor concentrates are asked to provide a serum or plasma specimen or both.

During the Community Counts baseline visit at an HTC, a serum specimen is collected and tested for HCV and HIV for participants 2 years old and older regardless of the treatment products used. If an individual has previously participated in the UDC surveillance project, serum specimens are collected and tested according to their previous UDC test results and interim treatment product exposure (blood bank products, plasma-derived factor concentrates, or unknown interim treatment product use). After the baseline visit, subsequent year serum collection and testing is performed if participants have used one or more of the relevant treatment products.

In addition to serum specimen collection, a baseline plasma specimen is collected and tested for inhibitors to factor VIII (FVIII) or factor IX (FIX) for all participants deficient in FVIII or FIX (primarily, those with hemophilia A, hemophilia B or type 3 VWD) who have ever received blood products or FVIII/FIX concentrates (recombinant or plasma-derived) or have an unknown treatment product history. Subsequent year plasma collection and testing is performed if participants have used these products one or more times or have used an unknown interim treatment product.

Inclusion Criteria

This Report represents baseline data from 9,173 males with hemophilia. Data from Registry “Initial Visit” forms collected from male participants with hemophilia A or B are included in this Report; females were excluded (n=499). The data were collected from December 2013 through December 2017. Information from the 42 participants enrolled in December 2013 were also included in this Report. When applicable, data from males in the Registry are compared to data from males with hemophilia A and B in the HTC PP. Of 141 HTCs, 133 contributed data during the first 3 years of data collection.


  1. De-identified means that the person’s identity cannot be connected with the information because personal identifiers, such as name, address, and birthdate, have been removed.
  2. Most data for a given year are reported by February of the following year, but some records may be received later.
  3. The actual interval between data collection episodes may be as little as nine months or significantly longer than a year, depending upon the participant’s routine schedule for comprehensive visits. Participants with disorders having a mild clinical course may not attend a comprehensive visit every year.