Evaluation of the utility of the ISTH-BAT in haemophilia carriers: a multinational study

Nonsevere Hemophilia: The Need for a Renewed Focus and Improved Outcomes

People with nonsevere hemophilia (PWNSH) are phenotypically more diverse than those with severe hemophilia. Perceptions relating to a "nonsevere" phenotype have contributed to fewer research initiatives, fewer guidelines on optimal management, and a lack of standards for surveillance and clinical assessment for affected individuals. In many cases, episodes of abnormal bleeding could, if investigated, have led to earlier diagnosis. Furthermore, the major recent developments in therapy for hemophilia have largely focused on severe disease and, as a group, PWNSH have not been included in many key clinical trials. Benefiting people with severe disease, innovative replacement therapies have generally targeted factor levels that are above those present in a large proportion of PWNSH. Therapeutic advances can lead to improvement in phenotype for people with severe hemophilia over that currently experienced by many PWNSH. As a result, we are approaching a point where PWNSH may, in many countries, have a higher risk of bleeding and restriction in lifestyle than those with severe disease but with more limited therapeutic options. Given the multiple major advances in treatment for people with hemophilia, it is timely to review the aspects of nonsevere disease, to ensure equity in care and management for all individuals with this condition.

Bleeding risk in hemophilia A and B carriers: comparison of factor levels determined using chronometric and chromogenic assays

BACKGROUND

Predicting the bleeding risk in hemophilia A and B carriers (HAC, HBC) is challenging.

OBJECTIVE

The objectives of this study were to describe the bleeding phenotype in HAC and HBC using the standardized Tosetto bleeding score (BS); to determine whether the BS correlates better with factor levels measured with a chromogenic assay than with factor levels measured with chronometric and thrombin generation assays; and to compare the results in HAC and HBC.

METHODS

This ambispective, noninterventional study included obligate and sporadic HAC and HBC followed at a hemophilia treatment center between 1995 and 2019.

RESULTS AND CONCLUSION

The median BS (3, range 0-21 vs. 3.5, range 0-15, P  = ns, respectively) and the abnormal BS rate (35.6% vs. 38.2%, P  = ns) were not significantly different in 104 HAC and 34 HBC (mean age: 38 years, 6-80 years). However, some differences were identified. The risk of factor deficiency was higher in HBC than HAC. Specifically, Factor VIII activity (FVIII):C/Factor IX activity (FIX):C level was low (<40 IU/dl) in 18.3% (chronometric assay) and 17.5% (chromogenic assay) of HAC and in 47% and 72.2% of HBC ( P  < 0.001). Moreover, the FIX:C level thresholds of 39.5 IU/dl (chronometric assay) and of 33.5 IU/dl (chromogenic assay) were associated with very good sensitivity (92% and 100%, respectively) and specificity (80% for both) for bleeding risk prediction in HBC. Conversely, no FVIII:C level threshold could be identified for HAC, probably due to FVIII:C level variations throughout life.

Gender equity in hemophilia: need for healthcare, familial, and societal advocacy

Hemophilia is a rare bleeding disorder caused by a genetic defect on chromosome X. It is inherited as an X-linked trait, and hence, it is more frequently diagnosed in males, whereas women have been traditionally considered only as carriers of the disease. However, the role of women in families of patients with hemophilia is pivotal. As mothers, sisters, daughters, and female partners of patients with hemophilia, they play a central role in the management of the patient, considering healthcare, social, and familial aspects, but they might be affected by the disease as well, particularly in regions where consanguinity is frequent. This paper aims to explore the involvement of women in hemophilia, including their carrier status, bleeding symptoms, treatment challenges, and psychosocial impact not only related to male patients, but also as patients affected with hemophilia themselves. We advocate health equity, equal access to healthcare for men and women with hemophilia and dedicated resources to improve the unique needs of the women dealing with hemophilia, ultimately leading to improved care and quality of life.

Women and girls with inherited bleeding disorders: Focus on haemophilia carriers and heavy menstrual bleeding

Raising awareness and improving recognition, accurate classification, and enhanced access to new treatments represent current key challenges for carriers of haemophilia. Women and girls carrying genes for haemophilia often experience significant bleeding and/or low factor levels. The bleeding associated with female haemophilia is frequently overlooked, has a weak correlation with factor levels, and manifests differently than in males, with heavy menstrual bleeding being a predominant symptom. Recent changes in terminology now allow the diagnosis of haemophilia in females with low factor levels and differentiate between symptomatic and asymptomatic carriers of the gene. Observations from real-world experiences and limited clinical trial data have highlighted the positive impact of various new haemophilia treatments for women and girls with clotting factor deficiencies. There is an urgent need for initiatives that increase their access to these treatments and encourage well-designed clinical trials focusing on female-specific outcomes. In women with inherited bleeding disorders, early recognition and optimal management of heavy menstrual bleeding are crucial. However, treatment options and guidance from high-quality clinical trials are currently insufficient. Menstrual health assessment should be a regular part of monitoring women and girls with inherited bleeding disorders throughout their lives, emphasizing the importance of gathering data to improve future management.

Factor activity levels and bleeding scores in pediatric hemophilia carriers enrolled in the ATHNdataset

BACKGROUND

Multiple studies have now shown that a significant proportion of hemophilia carriers meet the criteria for having hemophilia and/or report abnormal bleeding. However, to date, investigations of hemophilia carriers have almost exclusively involved women over 18 years of age. Little is known about factor activity levels and bleeding scores in carriers during childhood. We queried a large deidentified database of subjects with bleeding disorders residing in the United States to determine factor activity levels and bleeding scores.

PROCEDURES

The ATHNdataset was queried for hemophilia carriers under 18 years of age. Collected information included demographics, factor activity levels, and bleeding scores.

RESULTS

Over 700 carriers in the pediatric age group were identified, of which 626 submitted factor activity levels. Nearly half had factor activity levels less than 40 IU/dL, thereby meeting criteria for having hemophilia. Of those reporting bleeding scores, only 13.5% reported an abnormal bleeding score for age. The proportion reporting abnormal bleeding scores was higher in those with factor levels less than 40 IU/dL (23%) than those greater than 40 IU/dL (9.7%).

CONCLUSIONS

The proportion of pediatric carriers with hemophilia was double of that previously reported for adults. Of those with hemophilia reporting a bleeding score, the majority (77%) did not report an abnormal bleeding score for age. However, nearly 10% of pediatric carriers not meeting criteria for having hemophilia reported abnormal bleeding scores for age. Similar results are reported in adults suggesting that factor activity levels may not be predictive of bleeding symptoms in carriers.

Association of Genetic Variant FVIII Gene and Factor VIII: A Pilot Study Among Hemophilia A Female Relatives in Saudi Arabia

Hemophilia A (HA) is an X-linked recessive disorder that results from mutations in the factor VIII gene (FVIII). Most affected patients are males due to the inheritance of mutations in the FVIII gene from their mothers. Females are mostly found to be carriers unless they inherited the mutation from both parents. Obligate carriers of HA are mothers whose sons are affected with HA, or daughters who inherit the mutation from their affected fathers. A possible carrier of HA could be any female who has one or more affected relatives with HA in her family. Hemophilia A carriers (HACs) could present with similar symptoms to affected patients, including low factor VIII level, and risk of bleeding especially after surgical procedures or postpartum hemorrhage.

OBJECTIVES

 Assessing the phenotype of possible HAC and its association with genetic variants in the FVIII gene for better screening methods for HAC.

METHODS

From the period between 25 June and 25 October 2021, the study was conducted at King Abdulaziz University Hospital in Jeddah, Saudi Arabia. We recruited seven mothers whose sons were affected with HA, and 18 possible HAC who are relatives to sever affected patients with HA. All 25 candidates were assessed for the FVIII level, activated partial thromboplastin time (APTT), and bleeding risk and sequenced a part of Exon14 in their FVIII gene.

RESULTS

Twenty-five percent of the participants show a low level of FVIII, however, none of them have prolonged bleeding nor suffer from bleeding tendency. We also identified two missense variants in six of the candidates, but the clinical significance of these variants has not been determined previously.

CONCLUSION

This pilot study is the first to explore the phenotype of several HAC in Saudi Arabia. A larger scale study with more HA patients and their female relatives is needed to understand the correlation between phenotype and genotype for better screening for HAC.

Clotting Factor Deficiencies as an Underlying Cause of Abnormal Uterine Bleeding in Women of Reproductive Age: A Literature Review

Clotting Factor deficiencies are rare disorders with variations in clinical presentation and severity of symptoms ranging from asymptomatic to mild to life-threatening bleeding. Thus, they pose a diagnostic and therapeutic challenge, mainly for the primary health care providers, general practitioners, and gynecologists who are more likely to first encounter these patients. An additional diagnostic challenge arises from the variable laboratory presentations, as PT, PTT, and BT are not always affected. The morbidity is higher among women of reproductive age since Abnormal Uterine Bleeding-specifically Heavy Menstrual Bleeding-is one of the most prevalent manifestations of these disorders, and in some cases of severe deficiencies has led to life-threatening episodes of bleeding requiring blood transfusions or even immediate surgical intervention. Physician awareness is important as, in the case of some of these disorders-i.e., Factor XIII deficiency-prophylactic treatment is available and recommended. Although uncommon, the potential for rare bleeding disorders and for hemophilia carrier states should be considered in women with HMB, after more prevalent causes have been excluded. Currently, there is no consensus on the management of women in these instances and it is reliant on the physicians' knowledge.

Coexpression of factor VIII and factor von Willebrand variants in a woman with heavy menstrual bleeding

Heavy menstrual bleeding is one of the most common causes of consultation in haematology. We present the clinical case of a 20-year-old woman referred by her gynaecologist due to heavy menstrual bleeding since menarche, complicated by iron deficiency anaemia. Haemostasis work-up was initially suggestive of a von Willebrand disease type 1. Genetic analyses by whole exome sequencing lead to a fortuitous discovery of haemophilia by identifying a heterozygous missense mutation in F8 , exon 8 c.1127T>G:p.Val376Gly, previously reported in a patient with mild haemophilia A. The bleeding phenotype worsened by concomitant low von Willebrand factor (VWF) due to VWF variants influencing VWF levels. Our case highlights how whole exome sequencing can help to correct an erroneous diagnosis and identify polymorphisms that eventually contribute to the overall haemostatic balance.

Real-world analysis of patients with haemophilia A and haemophilia A carriers in the United States: Demographics, clinical characteristics and costs

INTRODUCTION

Females with haemophilia A (HA [FHAs]) and HA carriers (HACs) have an increased risk of bleeding and complications compared to the general population.

AIM

To examine the characteristics, billed annualised bleed rates (ABRb ), costs and healthcare resource utilisation for males with HA (MHAs), FHAs and HACs in the United States.

METHODS

Data were extracted from the IBM® MarketScan® Research Databases (Commercial and Medicaid) for claims during the index period (July 2016 to September 2018) and analysed across MHAs, FHAs and HACs.

RESULTS

Dual diagnosis females (DDFs; both HA and HAC claims) were grouped as a separate cohort. MHAs were generally younger than females (all cohorts) by up to 19 years (Commercial) and 23 years (Medicaid). ABRb  >0 was more frequent in females. Factor VIII claims were higher for MHAs versus female cohorts. Joint-related health issues were reported for 24.4 and 25.6% (Commercial) and 29.3 and 26.6% (Medicaid) of MHAs and FHAs, respectively; lower rates were reported in the other two cohorts. Heavy menstrual bleeding claims occurred for approximately a fifth (Commercial) to a quarter (Medicaid) of female cohorts. All-cause emergency department and inpatient visits in FHAs and DDFs were similar to, or more frequent than, those in MHAs; bleed-related inpatient visits were infrequent. In MHAs (Commercial), mean all-cause total costs ($214,083) were higher than in FHAs ($40,388), HACs ($15,647) and DDFs ($28,320) with similar trends for Medicaid patients.

CONCLUSIONS

FHAs and HACs may be undermanaged and undertreated. Further research is needed to fully understand these cohorts' bleeding rates, long-term complications and costs.

Building the foundation for a community-generated national research blueprint for inherited bleeding disorders: research priorities for ultra-rare inherited bleeding disorders

BACKGROUND

Ultra-rare inherited bleeding disorders (BDs) present important challenges for generating a strong evidence foundation for optimal diagnosis and management. Without disorder-appropriate treatment, affected individuals potentially face life-threatening bleeding, delayed diagnosis, suboptimal management of invasive procedures, psychosocial distress, pain, and decreased quality-of-life.

RESEARCH DESIGN AND METHODS

The National Hemophilia Foundation (NHF) and the American Thrombosis and Hemostasis Network identified the priorities of people with inherited BDs and their caregivers, through extensive inclusive community consultations, to inform a blueprint for future decades of research. Multidisciplinary expert Working Group (WG) 3 distilled highly feasible transformative ultra-rare inherited BD research opportunities from the community-identified priorities.

RESULTS

WG3 identified three focus areas with the potential to advance the needs of all people with ultra-rare inherited BDs and scored the feasibility, impact, and risk of priority initiatives, including 13 in systems biology and mechanistic science; 2 in clinical research, data collection, and research infrastructure; and 5 in the regulatory process for novel therapeutics and required data collection.

CONCLUSIONS

Centralization and expansion of expertise and resources, flexible innovative research and regulatory approaches, and inclusion of all people with ultra-rare inherited BDs and their health care professionals will be essential to capitalize on the opportunities outlined herein.

Women and girls with haemophilia: A retrospective cohort study in China

INTRODUCTION

Women and girls with haemophilia (WGH) may have spontaneous/traumatic bleeding similar to that in males with haemophilia, and in addition excessive bleeding during menstruation and delivery.

AIM

To characterize WGH in China and provide guidance for better management.

METHODS

We retrospectively analysed the characteristics of WGH registered in the Haemophilia Treatment Center Collaborative Network of China (HTCCNC) Registry, including demographics, diagnosis and treatment, bleeding characteristics, obstetrical and gynaecological experiences, and surgical history.

RESULTS

A total of 61 females had confirmed haemophilia. Diagnosis and treatment were typically delayed, longer in mild haemophilia than in severe and moderate. The most frequently reported bleeding manifestations were haemarthrosis in severe and moderate patients, and cutaneous bleeding in mild patients. Among 45 postmenarcheal WGH, 21 (46.7%) had history of heavy menstrual bleeding, but only three received treatments. Prenatal diagnosis and management of perinatal haemorrhage were inadequate. Of 34 deliveries in 30 women, nine deliveries were complicated by postpartum haemorrhage, and 22 offspring carried mutations causing haemophilia. Forty-four surgical procedures were performed in 29 patients. Those procedures receiving preoperative coagulation factors coverage were significantly less likely to have excessive bleeding than those who did not (P = .003).

CONCLUSION

This is the first and largest study describing WGH in China. There are currently deficiencies in the identification, diagnosis, and management of these patients. Improving health insurance policies, establishing haemophilia centres, and multidisciplinary teams for bleeding and perinatal or perioperative management will help reduce morbidity and mortality.

Bleeding phenotype in nonsevere hemophilia by International Society on Thrombosis and Haemostasis bleeding assessment tool, bleeding frequency, and the joint status

Background

Although the phenotype of severe hemophilia has been well studied, there are still knowledge gaps in nonsevere hemophilia.

Objectives

The objective of this study was to characterize the clinical bleeding phenotype in nonsevere hemophilia and its association with different factor VIII/IX assessments.

Methods

This was a cross-sectional, multicenter study to investigate the bleeding phenotype in adults with nonsevere hemophilia by the number of bleeding and joint bleeding in the past 5 years, a joint score, and the International Society on Thrombosis and Haemostasis bleeding assessment tool (ISTH-BAT). Factor levels were analyzed by 1-stage (lowest in history and at study inclusion) and chromogenic assay (at study inclusion). Patients were enrolled between March 2015 and May 2019.

Results

Of the 111 patients (86 with mild and 25 with moderate hemophilia), 57 patients (54.8%) reported any bleeding and 24 (23.1%) any joint bleeding in the past 5 years. A joint score ≥1 was found in 44 patients (41.9%), an ISTH-BAT ≥4 in 100 patients (90.1%), and an ISTH-BAT joint item ≥1 in 50 patients (45.0%). Within the ISTH-BAT, muscle and joint bleeds showed the largest difference between mild and moderate hemophilia. The lowest factor VIII/IX level in patients' history was best associated with bleeding outcomes. Factor was inversely associated with joint bleeds (incidence rate ratio 0.88; 95% CI, 0.79-0.98), joint score, and ISTH-BAT (odds ratios from proportional odds ordinal logistic regression 0.92; 95% CI, 0.87-0.97; and 0.89; 95% CI, 0.86-0.93, respectively).

Conclusion

The occurrence of joint bleeding differentiated persons with mild and moderate hemophilia. The ISTH-BAT and lowest factor in patients' history provided valuable information of the bleeding phenotype in nonsevere hemophilia.

Considerations for shared decision management in previously untreated patients with hemophilia A or B

Recent advances in therapeutics are now providing a wide range of options for adults and children living with hemophilia. Although therapeutic choices are also increasing for the youngest individuals with severe disease, challenges remain about early management decisions, as supporting data are currently limited. Parents and healthcare professionals are tasked with helping children achieve an inclusive quality of life and maintain good joint health into adulthood. Primary prophylaxis is the gold standard to optimize outcomes and is recommended to start before 2 years of age. A range of topics need to be discussed with parents to aid their understanding of the decisions they can make and how these will affect the management of their child/children. For those with a family history of hemophilia, prenatal considerations include the possibility of genetic counseling, prenatal investigations, and planning for delivery, together with monitoring of the mother and neonate, as well as diagnosis of the newborn and treatment of any birth-associated bleeding. Subsequent considerations, which are also applicable to families where infant bleeding has resulted in a new diagnosis of sporadic hemophilia, involve explaining bleed recognition and treatment options, practical aspects of initiating/continuing prophylaxis, dealing with bleeds, and ongoing aspects of treatment, including possible inhibitor development. Over time, optimizing treatment efficacy, in which individualizing therapy around activities can play a role, and long-term considerations, including retaining joint health and tolerance maintenance, become increasingly important. The evolving treatment landscape is creating a need for continually updated guidance. Multidisciplinary teams and peers from patient organizations can help provide relevant information. Easily accessible, multidisciplinary comprehensive care remains a foundation to care. Equipping parents early with the knowledge to facilitate truly informed decision-making will help achieve the best possible longer-term health equity and quality of life for the child and family living with hemophilia.

Plain language summary

Points to be taken into account to help families make decisions to best care for children born with hemophilia Medical advances are providing a range of treatment options for adults and children with hemophilia. There is, however, relatively limited information about managing newborns with the condition. Doctors and nurses can help parents to understand the choices for infants born with hemophilia. We describe the various points doctors and nurses should ideally discuss with families to enable informed decision-making. We focus on infants who require early treatment to prevent spontaneous or traumatic bleeding (prophylaxis), which is recommended to start before 2 years of age. Families with a history of hemophilia may benefit from discussions before pregnancy, including how an affected child would be treated to protect against bleeds. When mothers are pregnant, doctors can explain investigations that can provide information about their unborn child, plan for the birth, and monitor mother and baby to minimize bleed risks at delivery. Testing will confirm whether the baby is affected by hemophilia. Not all infants with hemophilia will be born to families with a history of the condition. Identification of hemophilia for the first time in a family (which is 'sporadic hemophilia') occurs in previously undiagnosed infants who have bleeds requiring medical advice and possibly hospital treatment. Before any mothers and babies with hemophilia are discharged from hospital, doctors and nurses will explain to parents how to recognize bleeding and available treatment options can be discussed. Over time, ongoing discussions will help parents to make informed treatment decisions:• When and how to start, then continue, prophylaxis.• How to deal with bleeds (reinforcing previous discussions about bleed recognition and treatment) and other ongoing aspects of treatment. ○ For instance, children may develop neutralizing antibodies (inhibitors) to treatment they are receiving, requiring a change to the planned approach.• Ensuring treatment remains effective as their child grows, considering the varied needs and activities of their child.

Three-Decade Successive Establishment of Care for Women/Girls from Families with Haemophilia

Objective

The study aimed to report a 3-decade successive establishment of care for women/girls from families with haemophilia.

Methods

A retrospective analysis was conducted on 462 women/girls from 243 families from 1987 to 2021.

Results

Combining phenotypic analysis of coagulation factor and genotypic analysis of either linkage analysis or mutation detection confirmed the status of all obligate haemophilia carriers (A118, B19). For potential carrier, 159 proven carriers (A130, B29) and 146 noncarrier status (A126, B20) were diagnosed except 20 potential carriers (A16, B4). Only 54 prenatal diagnoses were requested resulting in normal males (n = 21), males with haemophilia A (n = 12) and females with either normal or carrier status (n = 21). Additionally, 40 women/girls with haemophilia carrier received a diagnosis of severe haemophilia A with Turner’s syndrome (n = 2) and mild haemophilia (A31, B7). The skewed X-chromosome inactivation of the nonmutant factor VIII/IX carrying X-chromosome of 8% (2/25) was found in mild haemophilia. Factor concentrate and desmopressin are prescribed for these affected women/girls. The response of women/girls with either haemophilia carrier or haemophilia was amazement with their religious beliefs and cultural acceptance.

Conclusion

Appropriate care for women/girls from families with haemophilia concerning diagnosis and management of haemophilia and carrier has been successively established.

Managing Pregnant Women with Hemophilia and von Willebrand Disease: How Do We Provide Optimum Care and Prevent Complications?

The challenge of pregnancy can be significant to the point of being life-threatening in a woman with a bleeding disorder. Additionally there can be a risk to the fetus and the neonate. A hemostatic defect can affect the course of the pregnancy, but the impact is most feared around delivery in the immediate and the extended post partum period, requiring rapid identification and prompt referral to a hematologist for assistance in management. Identifying the type of congenital bleeding disorder and knowing its inheritance pattern is crucial during counseling prior to conception and in preparation for delivery. A comprehensive approach by a specialized and experienced team in a tertiary care center with access to adequate laboratory monitoring and therapies can facilitate the process. The multidisciplinary team should include a hematologist, an obstetrician, a pediatric hematologist, an anesthesiologist, and in select cases a clinical geneticist and a maternal fetal medicine specialist. In this review article, we will detail the diagnostic path and management of pregnancy and delivery in women with some inherited bleeding disorders, in particular those affected by hemophilia A (HA), hemophilia B (HB), and von Willebrand disease (VWD).

Hemostatic and thrombotic disorders in the pediatric patient

This review focuses on significant advances in the field of pediatric hemostasis and thrombosis, with a focus on published studies within the past decade. The evaluation and management of patients with excessive bleeding remain cornerstones of consultative hematology. We will describe the development of validated bleeding assessment tools relevant to pediatric practice, laboratory advances in the evaluation of von Willebrand disease, and a shift in clinical practice regarding the interpretation of normal coagulation studies in patients with significant bleeding phenotypes. There have also been critical advances in the management of hemostatic disorders. This review highlights new treatment paradigms in hemophilia and the rise of multidisciplinary medical homes for women living with bleeding disorders. Given the continued increase in the incidence of thrombosis, particularly in the hospital setting, a full call to arms against pediatric venous thromboembolism is now essential. We will describe recently completed clinical trials of direct oral anticoagulants in children and adolescents and ongoing work to elucidate the appropriate duration of therapy for children with provoked thrombosis. Recent work regarding the prevention of pediatric venous thromboembolism is highlighted, including studies of thromboprophylaxis and the development of risk prediction models for hospital-acquired thrombosis. Finally, we review advances in our understanding of thrombotic sequelae and the need for continued refinement of our evaluation tools. Despite the significant advances in pediatric hemostasis and thrombosis over the past decade, many unanswered questions remain for the next generation of investigators.

Challenges and knowledge gaps facing hemophilia carriers today: Perspectives from patients and health care providers

Background

Hemophilia carriers experience abnormal bleeding symptoms; however, a lack of awareness about this topic coupled with additional knowledge gaps and barriers leads to suboptimal care for this population.

Objective

The primary objective was to describe the current knowledge gaps and challenges from the perspective of both hemophilia carriers and their health care providers.

Methods

We carried out a mixed methods descriptive study with two population groups between September and December 2020. The hemophilia carrier perspective was obtained through both focus groups and questionnaires, whereas the health care providers perspective obtained via questionnaire sent to the Association of Hemophilia Care Directors of Canada and the Canadian Association of Nurses in Hemophilia Care. Focus groups were analyzed using descriptive thematic analysis and quantitative survey data was also analyzed.

Results

Eleven hemophilia carriers participated along with 19 health care providers (11 physicians, eight nurses). Hemophilia carrier focus group discussions identified four areas representing major challenges or knowledge gaps: (1) negative psychosocial impacts; (2) difficulty determining symptom significance; (3) need for self‐advocacy; (4) testing concerns. Survey results from both groups were aligned with the most important topics for ongoing education identified as information on abnormal bleeding symptoms, where to seek treatment, and considerations for heavy menstrual bleeding/menstruation. The majority of both study groups believe obligate or potential carriers should have factor levels checked regardless of age if symptoms of abnormal bleeding occur or before an invasive procedure. However, hemophilia carriers were significantly more in favor of genetic testing under the age of consent than health care providers in all scenarios evaluated.

Health issues in women and girls affected by haemophilia with a focus on nomenclature, heavy menstrual bleeding, and musculoskeletal issues

Introduction

Women and girls affected by haemophilia, including haemophilia carriers (WGH) are at risk of bleeding symptoms that may go unrecognized, including heavy menstrual bleeding (HMB) and musculoskeletal bleeding. Terminology continues to evolve.

Aim

To describe the current recommendations for nomenclature surrounding WGH, and the current understanding of HMB, iron deficiency, and musculoskeletal complaints in these patients.

Methods

Literature was reviewed and summarized.

Results

With regards to nomenclature, women with factor levels less than 50% should be classified as having haemophilia, while carriers with normal levels should be characterized accordingly to symptomatology. HMB and resultant iron deficiency are common among WGH, have a multitude of downstream effects, and maybe overlooked due to stigma around menstruation. Musculoskeletal bleeding and resultant joint changes are increasingly recognized in this population but do not necessarily correlate with factor levels.

Conclusion

Although progress has been made in the care of WGH, much work remains to further improve their care.

Management and outcomes of mild hemophiliacs and hemophilia carriers during pregnancy and peripartum period: a hemophilia treatment center experience in the United States

BACKGROUND

Pregnancy, peripartum management, and outcomes of mild hemophiliacs and hemophilia carriers in the United States are not well established.

AIM

To describe the management and outcomes of mild hemophiliacs and hemophilia carriers during assisted conception, pregnancy, peripartum and post-partum period at our hemophilia treatment center (HTC).

METHODS

Retrospective review of electronic medical records of pregnant women with mild hemophilia A or B (Factor VIII [FVIII] or Factor IX [FIX] level <0.4 IU/mL) and hemophilia A and B carriers followed at our HTC from January 2008 to October 2020. Demographics, the reason for diagnosis, FVIII and FIX levels at baseline and third trimester, bleeding phenotype and genotype were obtained. Method of conception, factor replacement, iron supplementation, mode of delivery, type of anesthesia, peripartum complications, and offspring outcomes was recorded.

RESULTS

There was a total of 18 pregnancies in 12 women (2 with mild hemophilia A, 2 mild hemophilia B, 6 hemophilia A carriers, and 2 hemophilia B carriers). Eleven pregnancies (61%) were conceived naturally and 7 (39%) via in-vitro fertilization (IVF). Eight (44.4%) and 10 (55.6%) pregnancies were vaginal and C-section deliveries, respectively. Neuraxial anesthesia was administered in 17 (94.4%) deliveries without complications. Four pregnancies (22.2%) had bleeding complications, 2 of which were post-partum hemorrhages not requiring transfusion.

CONCLUSION

In our case series of pregnant hemophilia carriers and mild hemophiliacs, successful outcomes were achieved with a carefully detailed multidisciplinary-driven approach.

The Clinical Genetics of Hemophilia B (Factor IX Deficiency)

Hemophilia B (HB) is a bleeding disorder caused by deficiency of or defect in blood coagulation factor IX (FIX) inherited in an X-linked manner. It results from one of over 1000 known pathogenic variants in the FIX gene, F9; missense and frameshift changes predominate. Although primarily males are affected with HB, heterozygous females may have excessive bleeding due to random or non-random X chromosome inactivation; in addition, homozygous, compound heterozygous, and hemizygous females have been reported. Somatic and germinal mosaicism for F9 variants has been observed. Development of antibodies to FIX treatment products (inhibitors) is rare and related to the type of causative variant present. Treatment is with products produced by recombinant DNA technology, and gene therapy is in clinical trials. Genetic counseling with up-to-date information is warranted for heterozygotes, potential heterozygotes, and men and women affected with HB.

Descriptive analysis of bleeding symptoms in haemophilia carriers enrolled in the ATHNdataset

BACKGROUND

Several studies have reported that haemophilia carriers have a bleeding tendency independent of factor activity. However, investigations have been fraught with methodological concerns. The ATHNdataset houses the largest data set of haemophilia carriers in the world. We undertook an analysis of haemophilia carriers in this data set using methodologies that characterize bleeding symptoms in carriers.

AIM

Determine the proportion of haemophilia carriers who have a normal bleeding score (BLS) and factors that affect the BLS.

METHODS

The ATHNdataset was queried for haemophilia carriers with a documented BLS. Collected data included demographics, ISTH-BAT score, factor activity level, type of haemophilia (A or B), genotype and geographic residence.

RESULTS

Nine hundred twenty-two haemophilia carriers in the ATHNdataset reported a BLS. When adjusted for age, 74% reported a normal score. Logistic regression identified age, factor activity level, ethnicity and region of residence as risk factors for an abnormal score.

CONCLUSIONS

The majority of haemophilia carriers (74%) in the ATHNdataset had a normal BLS, including the majority (59%) with factor activity levels < 40 IU/dl. Conversely, 24% of haemophilia carriers with a factor activity level > 40 IU/dl reported an abnormal BLS. These results are consistent with previous studies of haemophilia carriers. Additional investigation is needed to determine why a majority of haemophilia carriers with low factor activity levels report normal BLSs while a significant minority of haemophilia carriers with normal activity levels report abnormal BLSs.

Women and girls with haemophilia receiving care at specialized haemophilia treatment centres in the United States

INTRODUCTION

Females may have haemophilia with the same factor VIII (FVIII) or factor IX (FIX) levels as affected males. Characterization of females with haemophilia would be useful for health care planning to meet their unique needs. Federally-funded haemophilia treatment centres (HTCs) in the United States contribute data on all individuals with bleeding disorders receiving care to the Population Profile (HTC PP) component of the Community Counts Public Health Surveillance of Bleeding Disorders project.

AIMS

To estimate the number of females with haemophilia receiving care at HTCs in the United States and compare their characteristics with those of males with haemophilia.

METHODS

HTC PP data collected on people receiving care at an HTC from January 2012 through September 2020 with haemophilia A and B were evaluated by sex for demographic and clinical characteristics.

RESULTS

A factor level < 40% was reported for 23,196 males (97.8%) and 1667 females (47.6%) attending HTCs; 51 (.48%) severe, 79 (1.4%) moderate, and 1537 (17.9%) mild haemophilia patients were female. Females were older, more often White, and less often non-Hispanic than males. Females were less likely to have history of HIV or HCV infection, even among those with severe disease, but twice as likely to have infection status unknown. Females with mild haemophilia were more often uninsured than males.

CONCLUSIONS

Females with severe or moderate haemophilia are uncommon, even in specialized care centres; however, almost one in five patients with mild haemophilia was female, indicating needs for specialized care based on factor level and history for affected females.

Hemophilia A (Factor VIII Deficiency)

Remarkable changes are occurring in the diagnosis and management of individuals with hemophilia A. Genetic testing, including next-generation sequencing, enables family planning, carrier testing, and prenatal diagnosis. Musculoskeletal ultrasound examination facilitates the early detection of acute bleeds and joint disease in clinic, enabling more rapid bleed resolution and treatment planning. Novel therapies offer simpler weekly or monthly administration, some by subcutaneous injection, with better compliance and quality of life, as well as fewer bleeds. Gene therapy provides a 1-time phenotypic "cure" that is cost effective, but may be complicated by waning levels, vector immune responses, and hepatotoxicity.

A new hemophilia carrier nomenclature to define hemophilia in women and girls: Communication from the SSC of the ISTH

Hemophilia A and B predominantly attracts clinical attention in males due to X-linked inheritance, introducing a bias toward female carriers to be asymptomatic. This common misconception is contradicted by an increasing body of evidence with consistent reporting on an increased bleeding tendency in hemophilia carriers (HCs), including those with normal factor VIII/IX (FVIII/IX) levels. The term HC can hamper diagnosis, clinical care, and research. Therefore, a new nomenclature has been defined based on an open iterative process involving hemophilia experts, patients, and the International Society on Thrombosis and Haemostasis (ISTH) community. The resulting nomenclature accounts for personal bleeding history and baseline plasma FVIII/IX level. It distinguishes five clinically relevant HC categories: women/girls with mild, moderate, or severe hemophilia (FVIII/IX >0.05 and <0.40 IU/ml, 0.01-0.05 IU/ml, and <0.01 IU/ml, respectively), symptomatic and asymptomatic HC (FVIII/IX ≥0.40 IU/ml with and without a bleeding phenotype, respectively). This new nomenclature is aimed at improving diagnosis and management and applying uniform terminologies for clinical research.

Regulation and importance of factor VIII levels in hemophilia A carriers

PURPOSE OF REVIEW

To summarize the recent literature related to female hemophilia A carriers with respect to prevalence in the population, the impact of baseline factor VIII levels and other influences on bleeding phenotype, and clinical management needs.

RECENT FINDINGS

Many female hemophilia A carriers are at risk for abnormal bleeding, yet they are underrecognized by healthcare providers and their bleeding symptoms are underreported. Low FVIII levels are consistently associated with clinically significant bleeding and correlate well with skewed X chromosome inactivation (XCI). Most interestingly, bleeding tendency is also observed in some hemophilia A carriers with normal factor VIII levels and requires further investigation. Well controlled studies investigating peripartum and periprocedural FVIII levels and adequate hemostatic treatment are necessary to inform management guidelines.

SUMMARY

Prevalence and bleeding tendency of hemophilia A carriers remain underreported, despite a significant proportion having low FVIII levels. Skewed XCI may explain low FVIII but does not explain the bleeding risk encountered in a larger proportion of hemophilia A carriers with random XCI and borderline/normal FVIII.

ASH ISTH NHF WFH 2021 guidelines on the diagnosis of von Willebrand disease

BACKGROUND

von Willebrand disease (VWD) is the most common inherited bleeding disorder known in humans. Accurate and timely diagnosis presents numerous challenges.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH), the International Society on Thrombosis and Haemostasis (ISTH), the National Hemophilia Foundation (NHF), and the World Federation of Hemophilia (WFH) are intended to support patients, clinicians, and other health care professionals in their decisions about VWD diagnosis.

METHODS

ASH, ISTH, NHF, and WFH established a multidisciplinary guideline panel that included 4 patient representatives and was balanced to minimize potential bias from conflicts of interest. The Outcomes and Implementation Research Unit at the University of Kansas Medical Center (KUMC) supported the guideline-development process, including performing or updating systematic evidence reviews up to 8 January 2020. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE Evidence-to-Decision frameworks, to assess evidence and make recommendations, which were subsequently subject to public comment.

RESULTS

The panel agreed on 11 recommendations.

CONCLUSIONS

Key recommendations of these guidelines include the role of bleeding-assessment tools in the assessment of patients suspected of VWD, diagnostic assays and laboratory cutoffs for type 1 and type 2 VWD, how to approach a type 1 VWD patient with normalized levels over time, and the role of genetic testing vs phenotypic assays for types 2B and 2N. Future critical research priorities are also identified.

Managing women-specific bleeding in inherited bleeding disorders: A multidisciplinary approach

INTRODUCTION

Multidisciplinary management of women-specific bleeding is important to preserve quality of life, healthy reproduction and social participation of women and girls with bleeding disorders (WBD).

AIM

To support appropriate multidisciplinary care for WBD in haemophilia treatment centres.

METHODS

Two case examples are presented and management issues discussed from different health care perspectives, including the nurse, patient, psychologist, gynaecologist, geneticist, psychosexual therapist and haematologist.

RESULTS

Woman with bleeding disorders may experience heavy menstruation from menarche onwards. This has a physical and psychosocial impact requiring a multidisciplinary approach. If a woman with an inherited bleeding disorder desires to become pregnant, preconception counselling is essential, to discuss genetic diagnosis, state of the art treatment options for the bleeding disorder in question and possible choices to prevent having an affected child, as well as maternal bleeding risks during conception, delivery and the post-partum period.

CONCLUSION

Adequate management and good education of WBD requires a patient-centred multidisciplinary approach with experienced specialists in a haemophilia treatment centre.

How I manage pregnancy in carriers of hemophilia and patients with von Willebrand disease

Women with inherited bleeding disorders, including carriers of hemophilia A and B, or with von Willebrand disease, have an increased risk of bleeding during pregnancy and delivery. The unborn child may also be affected by the bleeding disorder for which specific measures have to be considered. This requires a multidisciplinary approach, with a team that includes a hematologist, a pediatric hematologist, a clinical geneticist, an obstetrician-perinatologist, and an anesthesiologist. An optimal approach includes prepregnancy genetic counseling, prenatal diagnostic procedures, and a treatment plan for delivery for both the mother and child. Recent retrospective studies show that even if strict guidelines are followed, these women are still at risk of postpartum bleeding. This occurs even if coagulation factor levels are normalized, either due to the pregnancy-induced rise of factor levels or by infusion of coagulation factor concentrates at the time of delivery. In this article, we describe our current diagnostic and clinical management of pregnancy and delivery in women with inherited bleeding disorders. We also briefly discuss possible interventions to improve the outcome of current strategies by increasing target factor levels during and after delivery.

Genetic causes of haemophilia in women and girls

Women and girls reported as "haemophilic females" may have complex genetic causes for their haemophilia phenotype. In addition, women and girls may have excessive bleeding requiring treatment simply because they are heterozygous for haemophilia alleles. While severe and moderate haemophilia are rare in females, 16% of patients with mild haemophilia A and almost one-quarter of those with mild haemophilia B seen in U.S. haemophilia treatment centres are women and girls. A phenotypic female with a low level of factor VIII or factor IX may be classified into one of the following categories of causality: homozygosity (two identical haemophilia alleles), compound heterozygosity (two different haemophilia alleles), hemizygosity (one haemophilia allele and no normal allele), heterozygosity (one haemophilia allele and one normal allele), genetic causes other than haemophilia and non-genetic causes. Studies required for classification may include coagulation parameters, F8 or F9 sequencing, F8 inversion testing, multiplex ligation-dependent probe amplification, karyotyping and X chromosome inactivation studies performed on the patient and parents. Women and girls who are homozygous, compound heterozygous or hemizygous clearly have haemophilia, as they do not have a normal allele. Heterozygous women and girls with factor levels below the haemostatic range also meet the definitions used for haemophilia treatment.

Evaluation of bleeding symptoms and laboratory parameters related to bleeding in sisters of patients with hemophilia A and B

INTRODUCTION

Our purpose was to determine the bleeding risk of obligate and potential carriers, highlight the prophylactic applications before interventions for families and physicians.

METHOD

Forty-six sisters who had at least one family member with hemophilia A or B were included. Laboratory parameters were tested.Bleeding tendency interrogated by a detailed questionnaire.The results were compared with 43 healthy female controls.

RESULTS

Mean factor activity levels were significantly lower in sisters than control subjects (p = 0,004). Bleeding score was higher in sisters than controls (p = 0.001). Prolonged bleeding after minor injury was significantly higher in the sisters than control subjects (p = 0.008). Requiring further treatment due to prolonged bleeding after tooth extraction was significantly higher in sisters (p = 0.001). Sisters had postpartum hemorrhage lasting longer than 6 weeks than controls (p = 0.025). Menstrual period lasted longer in the sisters than controls (p < 0.001). Spontaneous epistaxis, oral and gingival bleeding were more frequently observed in sisters whose factor activity levels were 60 % or below (p = 0.014 and p = 0.047, respectively). There was no statistically significant difference between the severity of hemophilia in the affected family member and the factor levels in the sisters (p = 0.398).Spontaneous epistaxis has found to be significantly associated with the hemophilia severity in the family (p = 0.004).

CONCLUSION

Clotting factor levels were found to be lower in the sisters and associated with spontaneous epistaxis, oral and gingival bleeding.Also, regardless of clotting factor levels, sisters significantly experienced more bleeding problems.Our study demonstrated the importance of taking precautions for prolonged bleeding in cases where medical interventions are inevitable in these patients.

Women and bleeding disorders: diagnostic challenges

Women with bleeding disorders suffer from multiple bleeding symptoms, including easy bruising, epistaxis, bleeding from minor wounds and the oral cavity, and bleeding after dental work or surgery. However, women with bleeding disorders especially suffer from gynecologic and obstetrical bleeding. These symptoms often are not recognized as abnormal, and many women are left undiagnosed and without access to appropriate medical care. Additional challenges to diagnosing women with bleeding disorders include lack of access to appropriate laboratory testing and issues around disease classification and nomenclature. Efforts have been undertaken to address these challenges, including the development and validation of bleeding assessment tools and strategies to clarify diagnostic thresholds and algorithms for von Willebrand disease (VWD) and platelet function disorders. Efforts to improve communication with the nomenclature used for hemophilia carriers are also underway.

Bleeding severity in patients with rare bleeding disorders: real-life data from the RBiN study

Patients with hereditary rare bleeding disorders (RBDs) present with diverse hemorrhagic symptoms. Correlation between factor activity levels and clinical bleeding severity is poor for most RBDs. Threshold factor activity levels have been previously described in relation to bleeding severity but have not yet been validated. The Rare Bleeding Disorders in the Netherlands (RBiN) study is a nationwide cross-sectional study of patients registered in all 6 Dutch Haemophilia Treatment Centers with a known RBD and who are age 1 to 99 years. Bleeding scores were determined, and laboratory and clinical data were extracted from patient files. In all, 263 patients were included, of whom 202 (77%) attended the scheduled study visit. The median International Society of Thrombosis and Haemostasis (ISTH) bleeding assessment tool (BAT) score was 9. Correlations between baseline factor activity levels and ISTH BAT scores were strong for deficiencies in factor II (FII) (r = -0.792) and FX (r = -0.838) and were moderate for deficiencies of fibrinogen (r = -0.683), FV (r = -0.623), FVII (r = -0.516), FXIII (r = -0.516), and α2-antiplasmin (r = -0.594). There was no correlation for FXI deficiency (r = -0.218). The RBD BAT identified more women (94% vs 83%) and children (100% vs 71%) with an RBD than the ISTH BAT did. Importantly, 48% of patients had more severe bleeding than predicted for their baseline factor activity level. In addition, 34% of patients were predicted to be asymptomatic, but they actually had grade 2 (31%) or 3 (3%) bleeding. Bleeding severity in patients with RBDs is more pronounced than previously anticipated. The previously determined threshold factor activity levels to ensure no (spontaneous) bleeding in patients with an RBD are inaccurate. This trial was registered at www.clinicaltrials.gov as #NCT03347591.

X Chromosome inactivation: a modifier of factor VIII and IX plasma levels and bleeding phenotype in Haemophilia carriers

Haemophilia A and B are X-linked hemorrhagic disorders caused by gene variants in the F8 and F9 genes. Due to recessive inheritance, males are affected, while female carriers are usually asymptomatic with a wide range of factor VIII (FVIII) or IX (FIX) levels. Bleeding tendency in female carriers is extremely variable and may be associated with low clotting factor levels. This could be explained by F8 or F9 genetic variations, numerical or structural X chromosomal anomalies, or epigenetic variations such as irregular X chromosome inactivation (XCI). The aim of the study was to determine whether low FVIII or FIX coagulant activity in haemophilia carriers could be related to XCI and bleeding symptoms. HUMARA assay was performed on 73 symptomatic carriers with low clotting activity ≤50 IU/dL. Bleeding Assessment Tool (BAT) from the International Society on Thrombosis and Haemostasis (ISTH) was used to describe symptoms in the cohort of carriers. In 97% of haemophilia carriers, a specific gene variant in heterozygous state was found, which alone could not justify their low FVIII or FIX levels (≤50 IU/dL). A statistical association between XCI pattern and FVIII and FIX levels was observed. Moreover, female carriers with low coagulant activity (≤20 IU/dL) and high degree of XCI ( ≥ 80:20) had a higher ISTH-BAT score than the carriers with the opposite conditions (>20 IU/dL and <80:20). In our cohort of haemophilia carriers, XCI was significantly skewed, which may contribute to the low expression of clotting factor levels and bleeding symptoms.

Prospective evaluation of ISTH-BAT as a predictor of bleeding disorder in adolescents presenting with heavy menstrual bleeding in a multidisciplinary hematology clinic

BACKGROUND

Heavy menstrual bleeding (HMB) can be the first manifestation of an undiagnosed bleeding disorder (BD). Identifying a BD can be challenging in the adolescent age group. The utility of bleeding assessment tools (BAT) remains elusive in this population.

AIM

We evaluated the ability of the International Society on Thrombosis and Haemostasis-BAT (ISTH-BAT) in predicting a BD in adolescents referred for HMB to a multidisciplinary hematology clinic.

METHODS

Two hundred adolescents with HMB underwent a standardized evaluation for BD. The clinical characteristics, laboratory data, and bleeding scores (BS) assessed using ISTH-BAT were prospectively collected. Comparisons were made between patients based on the diagnosis of BD receiver operating characteristic (ROC) curve analyses of ISTH-BAT were performed to assess its value for predicting BD.

RESULTS

Overall, 33% (n = 67) of adolescents were diagnosed with a BD. The mean ISTH-BAT BS was higher in BD as compared to those without (4.1 versus 3.1, P < .0001), but the mean menorrhagia-specific scores did not differ (2.9 in both groups). The ISTH-BAT demonstrated a modest discriminative ability as a screening tool to identify BD in girls with HMB with an area under the curve (AUC) of 0.71. The ROC analysis demonstrated that with increasing BS, the sensitivity decreased, but the specificity increased. At BS = 3, sensitivity was 88%, specificity 31%, and accuracy 50%; at BS = 5, sensitivity was 37%, specificity 94%, and accuracy was 75%. There was no change thereafter.

CONCLUSION

In adolescents with HMB, an ISTH-BAT BS of >4 instead of the established cut-off of >2 in children is highly specific in predicting a BD.

Women and girls with haemophilia: Lessons learned

Severe and moderate factor VIII (FVIII) or IX (FIX) deficiencies in female carriers of haemophilia are rarely observed, but mild deficiency is quite frequent, although insufficiently recognized and registered. The confusion between the genetic diagnosis of the carriership, mainly assessed at adult age and the diagnosis of the bleeding disorder for those who have low factor levels often prevents early diagnosis of a potential bleeding risk. The factor levels in obligate or potential carriers of haemophilia can be assessed during childhood, possibly apart from genetic assays. The absence of early recognition of the bleeding disorder precludes the anticipation of menarche and the prevention of potential heavy menstrual bleeding to heavy menstrual bleeding. Standardized bleeding assessment tools (BAT) have demonstrated that women and girls with haemophilia (WGWH) have increased bleeding scores as compared to the general female population, however weakly correlating with factor levels. More recent evidence has highlighted that hemarthroses affect 4% to 19% of carriers and that some of them could experience sub-clinical joint bleeding. Desmopressin for women with FVIII deficiency and abnormal ISTH-BAT scores had a significantly lower FVIII response to DDAVP compared to those with normal bleeding scores, which could at least partially explain more postsurgical bleeding. Management of delivery of haemophilia carriers requires attention to the risks of maternal bleeding, the risks of foetal bleeding, preconception and prenatal care, strategies to reduce maternal bleeding, choice of mode of delivery to reduce foetal/neonatal bleeding, and postpartum care. Either prior to pregnancy, or during early pregnancy, a plan should be developed that addresses the needs of both the mother and her unborn baby. If the unborn baby is a male proven to be or potentially affected by moderate or severe form of haemophilia, there is a risk of severe foetal bleeding, so a planned caesarean delivery may be preferred. If the unborn baby is a carrier, or potentially affected carrier, there is still the risk of non-severe bleeding so invasive foetal procedures and operative vaginal delivery (forceps or vacuum) should be avoided. Further studies based on large cohorts will help the community to favour earlier diagnosis, increase knowledge on WGWH and promote better care.

The odds and implications of coinheritance of hemophilia A and B

We report 2 patients with coinheritance of the X-linked bleeding disorders hemophilia A and hemophilia B. We describe the family pedigrees, clinical features, and genotyping. The case report addresses the key clinical questions of how to manage patients with both hemophilia A and B and how to counsel families regarding recurrence risk. The patients with coinherited hemophilia A and B require a combination of factor VIII and factor IX replacement to achieve hemostasis. We calculated the estimated genomic meiotic recombination frequency between F8 and F9 to be 38%. The findings in these cases are consistent with this calculation. These findings provide critical information for management of families with coinherited hemophilia A and B.

Bone health in symptomatic carriers of haemophilia A: a protocol for a multicentre prospective matched-cohort study

INTRODUCTION

Haemophilia A is an X linked inherited bleeding disorder, caused by a decrease in coagulation factor VIII. Persons with haemophilia experience repeated musculoskeletal bleeding, which can lead to decreased range of motion, irreversible joint damage, low bone mineral density (BMD), and are at greater risk for osteoporosis. Women heterozygous for this mutation, also known as haemophilia A carriers, can have bleeding symptoms and even experience joint bleeding evidenced by radiological soft tissue and osteochondral changes. The prevalence of low BMD as a risk factor for osteoporosis has never been evaluated in carriers of haemophilia, and given the recent findings which suggest subclinical musculoskeletal bleeding in carrier women, we hypothesise that they too are at risk of impaired bone health.

METHODS AND ANALYSIS

This is a national multicentre prospective matched-cohort study to compare BMD T-scores among symptomatic haemophilia A carriers, 50 years of age or older, with age-matched and body mass index-matched non-carriers (1:1). A total of 40 symptomatic carriers and 40 matched non-carriers will be recruited from St. Michael's Hospital, Kingston General Hospital in Ontario, Canada and Foothills Medical Centre in Alberta, Canada. Multivariable linear regression models will be used to estimate the effect of haemophilia carriership on BMD T-scores, adjusting for age, body mass index and other relevant covariates.

ETHICS AND DISSEMINATION

The protocol was designed and will be conducted in compliance with applicable laws, rules and regulations. Research ethics approval was obtained from St. Michael's Hospital, Foothills Medical Centre, and Kingston General Hospital. Findings will be presented at international venues such as the American Society of Haematology and the World Federation of Haemophilia World Congress. The authors of this study will seek publication in journals such as Blood, Journal of Thrombosis and Haemostasis, American Journal ofHematology and British Journal ofHaematology.

A decreased and less sustained desmopressin response in hemophilia A carriers contributes to bleeding

The cause of hemophilia A carrier bleeding is not well established. Desmopressin (DDAVP), used clinically to treat or prevent bleeding, can also be used as a medical stress surrogate. This study's objective was to compare the response to DDAVP in hemophilia A carriers with that in normal control patients. Bleeding was assessed by the International Society on Thrombosis and Hemostasis Bleeding Assessment Tool (ISTH-BAT). DDAVP (0.3 μg/kg) was administered either IV or subcutaneously (SC), and blood was drawn at baseline and 1, 2, and 4 hours postadministration. Blood was assessed for factor VIII (FVIII) level, von Willebrand factor (VWF) antigen (VWF:Ag), VWF activity (VWF:RCo or VWF:GPIbM), thromboelastography (TEG), and thrombin generation assay (TGA) at all points, and for VWF propeptide (VWFpp):Ag ratio and ABO blood type at baseline. Carriers were older than control patients (median age, 34 and 21 years, respectively; P = .003) and had higher ISTH-BAT bleeding scores (median bleeding score, 8 and 0, respectively; P = .001). Carriers had a significantly reduced FVIII response to DDAVP compared with control patients (P ≤ .0001). When only carriers with normal baseline FVIII levels (n = 10) were included, carriers maintained a reduced FVIII response (P ≤ .0001). Furthermore, participants with abnormal bleeding scores had a significantly lower FVIII response to DDAVP compared with those with normal bleeding scores (P = .036). Hemophilia A carriers have a lower and less sustained FVIII response to DDAVP, suggesting an impaired ability to respond to hemostatic stress, which contributes to bleeding.

Joint comorbidities among Swedish carriers of haemophilia: A register-based cohort study over 22 years

BACKGROUND

A significant fraction of women with an impaired factor VIII or IX gene in the X chromosome, carriers of haemophilia, will have clotting factor activities corresponding to those seen in males with non-severe haemophilia, hence, experience an increased bleeding tendency. Data describing the long-term joint outcomes among carriers are limited. We compared the age at onset, frequency of joint-related diagnoses as well as joint surgery and related hospitalizations among carriers of haemophilia with sex- and birthdate-matched controls from the general population.

METHODS

Carriers of haemophilia born 1941-2008 were identified through the haemophilia treatment centres' (HTCs) databases and the National Patient Register of Sweden. For each carrier, we included up to five individuals using the Swedish population register as comparisons. Data for the period 1987-2008 were obtained.

RESULTS

Among 539 potential carriers identified, 213 had a known factor activity. Carriers with reduced factor activity and those with unknown factor activity had received their first joint-related diagnosis at a significantly earlier age than their comparisons. The same subgroups showed an overall 2.3- and 2.4-fold higher hazard for joint-related diagnoses compared with the general population. In addition, the hazards of joint-related outpatient hospitalization were 3.2-fold (95% CI: 1.2, 9.1) and 2.5-fold (95% CI: 1.6, 3.7). This was not observed for those with normal factor activity.

CONCLUSION

Carriers of haemophilia suffer a significant risk for joint comorbidities. This risk seems to correlate to the factor activity. Our findings underline the importance of regular clinical follow-up of carriers at HTCs.

Women and inherited bleeding disorders - A review with a focus on key challenges for 2019

The area of women and inherited bleeding disorders has undergone quick expansion in recent years. More patients are being identified and expertise to diagnose and manage these patients is now essential for practising physicians. Programs to help educate and empower patients and caregivers are now in place. Common inherited bleeding disorders affecting women include von Willebrand disease (VWD), inherited platelet disorders, and rare inherited bleeding disorders such as factor VII (FVII) deficiency and factor XI (FXI) deficiency. Specific clinical tools have been developed to help clinicians and patients screen for the presence of these bleeding disorders in both adult and pediatric populations. Affected women can experience heavy menstrual bleeding and resulting iron deficiency anemia, postpartum hemorrhage, and hemorrhagic ovarian cysts which need to be properly managed. Excessive bleeding can adversely affect quality of life in these women. Front line therapy for bleeding in mild cases focuses on the use of non-specific hemostatic agents such as DDAVP ®, tranexamic acid and hormonal agents but specific factor replacement and/or blood products may be required in more severe cases, in severe bleeding or as second line treatment when bleeding is not responsive to first line agents. Iron status should be optimised in these women especially in pregnancy and use of an electronic app can now help clinicians achieve this. These patients should ideally be managed by a multidisciplinary team whenever possible even remotely. Although clinical research has closed some knowledge gaps regarding the diagnosis and management of these women, there remains significant variation in practise and lack of evidence-based guidelines still exists in many spheres of clinical care in which caregivers must rely on expert opinion. Ongoing efforts in education and research will continue to improve care for these women and restore quality of life for them.

Mathematical model of thrombin generation and bleeding phenotype in Amish carriers of Factor IX:C deficiency vs. controls

INTRODUCTION

Factor IX:C (FIX:C) levels vary in hemophilia B carriers even in pedigrees with a unifying genetic defect. Analyzing the balance between pro-and anticoagulants might increase our understanding of carriers' bleeding potential.

AIM

In this research study, we evaluated bleeding scores (BS) and a novel mathematical model of thrombin generation (TG) in Amish FIX:C deficient carriers and controls.

METHODS

Blood samples and BS were obtained from post-menarchal females, including 59 carriers and 57 controls from the same extended pedigree. Factors II, V, VII, VIII, IX, X, antithrombin, tissue factor pathway inhibitor and protein C were assayed to generate mathematical models of TG in response to 5pM tissue factor (TF) and for TF + thrombomodulin. BS was based on a modification of the MCMDM-1VWD scoring system.

RESULTS

Carriers had a lower mean FIX:C (68% vs. 119%), von Willebrand factor antigen (108 vs.133) and Tissue activatable fibrinolysis inhibitor (103 vs. 111) compared to controls; both groups had a similar mean BS. Carriers demonstrated significantly lower TG parameters on both mathematical models compared to controls. Carriers with FIX:C ≤ 50% had lower TG curves than those >50% but similar BS.

CONCLUSION

Thrombin generation showed significant differences between carriers and controls, between low (≤50%) and high (>50%) FIX:C carriers, and specifically in the TF + thrombomodulin model, between high FIX:C carriers and controls, although the BS were not different.

The national blueprint for pregnancy/birth longitudinal cohorts to study factor VIII immunogenicity: NHLBI State of the Science (SOS) Workshop on factor VIII inhibitors

INTRODUCTION

Patients with haemophilia can develop inhibitors to exogenous coagulation factors. Some patients are tolerant to factor, while those who develop inhibitors do so early in life. Genetics and environmental factors are known to contribute to inhibitor risk. However, it is not yet possible to predict inhibitor formation or treatment responsiveness in individuals. We hypothesize that factors in the antenatal/neonatal period inform inhibitor risk development.

AIM

To consider the design of longitudinal studies beginning in the antenatal/neonatal period and the use of new technologies to better understand haemophilia inhibitors.

METHODS

A working group was formed for the NHLBI State of the Science Workshop: Factor VIII Inhibitors: Generating a National Blueprint for Future Research to solicit input from the US haemophilia community and international collaborators to consider design of pregnancy/birth longitudinal cohorts that leverage -omics, existing phenotypic data, and in silico modelling to study inhibitors.

RESULTS

An antenatal/neonatal longitudinal cohort should begin with enrolment of pregnant genetic carriers of haemophilia and span the at-risk period for inhibitor development in the child. Data and samples from the mother, placenta, neonate and young child can be obtained that are amenable to existing assays, genomics and other -omics studies. Data can inform in silico prediction and mathematical models.

CONCLUSION

A longitudinal study beginning before birth offers the unique opportunity to study factors that influence inhibitor development prior to exposure. Advances in -omics and computational biology can study complex phenotypes in this rare disease. This study could be accomplished through interdisciplinary efforts and patient community engagement.