A Summary of HFA鈥檚 Blood Brotherhood & Families Inhibitor Survey Data


Many people with hemophilia A or B or type 3 von Willebrand disease (vWD) treat by infusing clotting factor concentrates into their veins, which helps form clots, and stop or prevent bleeding episodes. Of those who infuse with clotting factor, some will develop an inhibitor, or an antibody, to that clotting factor, making the treatment less effective or in some instances ineffective, which results in bleeding episodes that are more prolonged or difficult to stop.

Inhibitor development is one of the most serious and costly medical complications of having a bleeding disorder. The sooner an inhibitor is identified, the sooner treatment to get rid of the inhibitor can begin. Prompt diagnosis and treatment of an inhibitor increases the success rate of getting rid of the inhibitor and reduces complications of bleeding. For these reasons, it is recommended that people get tested for an inhibitor every year.

Hemophilia Federation of America surveyed participants enrolled in its Blood Brotherhood and Families programs聽to better understand their knowledge and awareness about inhibitor development, risk factors and testing. A total of 107 men (diagnosed with hemophilia A or B) in the Blood Brotherhood program and 95 caregivers (of children younger than 25 years old and diagnosed with hemophilia A or B) in the Families program completed the survey. HFA used this knowledge to inform our educational programming activities. The following highlights what program participants reported about inhibitors and gaps in knowledge and awareness that is now being addressed in HFA programming.

Blood Brotherhood


Knowledge and Awareness of Inhibitors

To learn more about participants鈥 current knowledge of inhibitors, we examined if respondents knew that an inhibitor is the development of antibodies by the immune system because it sees the infused clotting factor as a foreign substance that needs to be destroyed. We also examined if respondents knew one of the formal names of the method聽used for inhibitor testing was the Nijmegen-Bethesda Assay (NBA). Finally, we asked respondents to select the medium or how inhibitor testing is measured, in the blood, and not urine or saliva. The results for the Blood Brotherhood and Families participants are below.

Most participants from both programs correctly identified what an inhibitor was, and that blood is how the inhibitor test is measured. However, only approximately half of the participants were able to correctly identify the formal name used for the method of inhibitor testing.

Knowledge and Awareness of Inhibitor Risks

We also asked participants about their knowledge of the risks for inhibitor development. One question asked if they could correctly identify one or more risk factor(s) for inhibitor development, specifically genetic mutation, type and severity of hemophilia, age and number of exposures to factor product, intensive factor therapy, race/ethnicity, and family history of an inhibitor. Another question asked if individuals could identify that people with hemophilia A and B and individuals with type 3 von Willebrand disease were at risk for inhibitor development. We also asked if people believed they (or their child) were at risk based on their (their child鈥檚) self-identified bleeding disorder diagnosis. While most participants could identify one or more inhibitor risk factor(s), only 35 percent of men were able to identify the genetic mutation as a risk factor.

Blood Brotherhood:

While approximately 90 percent of participants could correctly identify one or more risk factors for inhibitor development, only 36 percent were able to identify that the genetic mutation was a risk factor. Only 71 percent of men and 62 percent of caregivers could correctly identify who was at risk (by their bleeding disorder). And half of caregivers did not believe, or did not know, their children were at risk for an inhibitor.

The genetic mutation causing the participants hemophilia, is currently the strongest risk factor for inhibitor development, and health education and promotion is needed to increase HFA members knowledge regarding this. Additionally, more education is needed for men and caregivers that people with hemophilia A, B and type 3 vWD who infuse with clotting factor products are at risk for inhibitor development.

Knowledge and Awareness of the Frequency of Inhibitor Testing

  • 46% of men and 66% of caregivers at risk for inhibitor development identified they should be getting tested for inhibitors at least annually.
  • Caregivers who were not aware of the importance of getting tested annually had never had their child tested for an inhibitor or didn鈥檛 know about inhibitor testing.
  • Most caregivers had children who were using on-demand therapy, whereas among men who were not aware of the importance of getting tested annually, the majority did not perceive they were at risk and were on prophylaxis.

Patient-Provider Relationships

Patient awareness of inhibitors, including risk factors, how testing is done and treatment for inhibitors, often requires a strong relationship with medical providers. To better understand how survey participants came to their answers to the questions about awareness and risks, we asked:

  • if at the participant鈥檚 last comprehensive visit, had they talked to their (or their child鈥檚) provider about getting tested for an inhibitor?
  • how comfortable they were talking to their doctor about getting tested for an inhibitor?

Our results show that most participants feel comfortable talking to their provider about getting tested for an inhibitor, but many HFA Blood Brotherhood and Families program participants are not engaging in those discussions with their provider at their comprehensive visit. There may be a need to focus on patient-provider engagement regarding inhibitor testing.

Source of Inhibitor Information

In addition to learning about inhibitors through their doctors鈥 visits, we wanted to know what other ways participants of the HFA Blood Brotherhood and Families programs received information about inhibitors.

Blood Brotherhood and Families participants received inhibitor education from HFA mainly through educational webinars and social media. However, only approximately 25 percent of both Blood Brotherhood and Families participants received a majority of information on inhibitor development/testing from HFA.


Our findings regarding inhibitor knowledge are consistent across both Families and Blood Brotherhood program participants, and suggest that both groups can correctly identify what an inhibitor is, but additional education is needed for individuals to be able to:

  • Identify if they are at risk
  • Correctly identify the inhibitor testing method name (for advocacy)
  • Correctly identify all the risk factors for inhibitor development
  • Promote individuals at risk to get tested for an inhibitor
  • Encourage provider-patient conversations surrounding inhibitor development and testing.

HFA Symposium and Member Organization sessions appear to have the potential for the greatest educational impact, but one concern is the reach and impact of education using this delivery method as not everyone is able to attend local sessions or Symposium.

Patient-Provider Conversations

HFA recognizes the need to further improve awareness and knowledge of inhibitor testing and treatment among patients, families and caregivers. As a result, HFA has an educational inhibitor module in HFA鈥檚 Learning Central, HFA鈥檚 online learning platform. The module offers the opportunity for interactive, up-to-date, online learning about inhibitor information.

We would like to thank the HFA program participants who took their valuable time to complete the baseline survey. The information collected from this survey provided HFA with a better understanding of the knowledge about inhibitor development and where HFA could engage the community to increase knowledge and awareness. This information is not meant to be reflective of the knowledge of all Blood Brotherhood and Families program participants, however, the gaps identified provide HFA with a better understanding about what education is needed and how HFA can best deliver this education to meet the needs of our program participants. HFA will continue to use this data to develop interventions aimed at increasing knowledge and awareness about the signs, symptoms, risk factors and testing at risk individuals for inhibitors.


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