Introduction: In the network of U.S. comprehensive haemophilia treatment centres (HTCs), von Willebrand disease (VWD) is the most common bleeding disorder other than haemophilia. Estimates of the size and characteristics of the VWD population receiving treatment are useful for healthcare planning. Aim: Estimate the prevalence and incidence of VWD among males and females receiving care at U.S. HTCs (HTC-treated prevalence and incidence). Methods: During the period 2012–2019, de-identified surveillance data were collected on all VWD patients who visited an HTC including year of birth, sex, race, Hispanic ethnicity, VWD type, and laboratory findings and used to calculate period HTC-treated prevalence by VWD type and sex. Data from patients born 1995–1999 were used to estimate HTC-treated incidence rates. Results: During the period, 24,238 patients with a diagnosis of VWD attended HTCs; for 23,479 (96.9%), VWD type was reported or could be assigned. Age-adjusted HTC-treated prevalence was 8.6 cases/100,000 (7.2/100,000 for Type 1, 1.2/100,000 for Type 2 and 1.7/million for Type 3) and was twice as high in women as men (4.8 vs. 2.4 cases/100,000) for Type 1 and similar by sex for Type 2 and Type 3. HTC-treated Type 1 incidence increased over the period, averaging nearly threefold higher for women than men (26.2 vs. 9.9/100,000 live births). Sex differences were less for Type 2 (2.2 vs. 1.4 cases/100,000 births) and slight in Type 3. Conclusion: Prevalence and incidence of HTC-treated VWD differ by sex and type and are likely strongly influenced by differences in rates of diagnosis.

Introduction: Von Willebrand disease (VWD) is a common inherited bleeding disorder, but awareness among health care professionals is low. We estimated the number of cases of undiagnosed VWD or other mucocutaneous bleeding disorders among commercially insured patients in the United States with a recent history of bleeding events. Methods: Patients with a VWD diagnosis who were users of or candidates for von Willebrand factor replacement were identified from the IMS PharMetrics Plus Database (2006–2015). We constructed a unary patient-finding model based on 12 prediagnosis variables that best defined this population, and applied this to undiagnosed patients with recent bleeding events from the same database. Cases of symptomatic undiagnosed VWD or other mucocutaneous bleeding disorders in the commercially insured population were estimated from the “best fit” (positive predictive value [PPV] 83%) and “good fit” (PPV 75%) patients thus identified. Results: Overall, 507,668 undiagnosed patients with recent bleeding events were identified (86% female, 14% male). Application of the VWD model identified 3318 best-fit and 37,163 good-fit patients; 91% of best-fit patients were females aged <46 years, with heavy menstrual bleeding as the most common claim. Projection to the full commercially insured US population suggested that 35,000–387,000 patients may have symptomatic, undiagnosed VWD or other mucocutaneous bleeding disorders. Discussion: Computer modeling suggests there may be a significant number of patients with symptomatic, undiagnosed VWD or other mucocutaneous bleeding disorder in the commercially insured population. Enhanced awareness of VWD symptoms and their impact, and of screening and testing procedures, may improve the diagnosis of VWD and reduce disease burden.

Introduction: Haemophilia A is an X-linked recessive bleeding disorder that primarily affects males. Emerging data support evidence for increased bleeding in female haemophilia A carriers despite factor VIII activity within the normal range. Aim: Data regarding the effect of increased bleeding on health-related quality of life (HR-QOL) in haemophilia A carriers is sparse. We tested the hypothesis that haemophilia A carriers have reduced HR-QOL related to bleeding symptoms. Methods: We conducted a cross-sectional study at Vanderbilt University. Case subjects were obligate or genetically verified haemophilia A carriers age 18 to 60 years. Control subjects were mothers of children with cancer who receive care at the Vanderbilt pediatric hematology-oncology clinic. Trained interviewers administered the Rand 36-Item Health Survey 1.0, a validated questionnaire evaluating eight health concepts that may affect HR-QOL, to each study participant. Mann-Whitney U tests were used to compare median scores for the eight health domains between the case and control groups. Result: Forty-two haemophilia A carriers and 36 control subjects were included in analyses. Haemophilia A carriers had significantly lower median scores for the domains of “Pain” (73.75 versus 90; p= 0.02) and “General health” (75 versus 85; p= 0.01) compared to control subjects. Conclusion: Haemophilia A carriers in our study demonstrated significantly lower median scores on the Rand 36-item Health Survey 1.0 in the domains of “Pain” and “General Health” compared to women in the control group. Our findings highlight the need for further investigation of the effect of bleeding on HR-QOL in this population.

Vitamin K deficiency bleeding (VKDB) is a coagulopathy that develops in infants who do not have sufficient vitamin K stores to support production of clotting factors. In adults, vitamin K is absorbed from food and from vitamin K synthesized by gut bacteria. However, placental transfer in humans is limited; cord blood and infant liver reserve levels of vitamin K are substantially below adult levels. As a result, infants are predisposed to develop VKDB, which is classified as early, classic, and late, according to when it presents. In the United States, administration of intramuscular vitamin K at birth to prevent all forms of VKDB has been standard practice since first recommended by the American Academy of Pediatrics in 1961. Without this prophylaxis, incidence of early and classical VKDB ranges from 0.25% to 1.7% of births; incidence of late VKDB ranges from 4.4 to 7.2 per 100,000 infants. The relative risk for developing late VKDB has been estimated at 81 times greater among infants who do not receive intramuscular vitamin K than in infants who do receive it.

The etiology of severe hemolytic anemia in most patients with recessive hereditary spherocytosis (rHS) and the related disorder hereditary pyropoikilocytosis (HPP) is unknown. Whole-exome sequencing of DNA from probands of 24 rHS or HPP kindreds identified numerous mutations in erythrocyte membrane α-spectrin (SPTA1). Twenty-eight mutations were novel, with null alleles frequently found in trans to missense mutations. No mutations were identified in a third of SPTA1 alleles (17/48). WGS revealed linkage disequilibrium between the common rHS-linked αBH polymorphism and a rare intron 30 variant in all 17 mutation-negative alleles. In vitro minigene studies and in vivo splicing analyses revealed the intron 30 variant changes a weak alternate branch point (BP) to a strong BP. This change leads to increased utilization of an alternate 3′ splice acceptor site, perturbing normal α-spectrin mRNA splicing and creating an elongated mRNA transcript. In vivo mRNA stability studies revealed the newly created termination codon in the elongated transcript activates nonsense-mediated decay leading to spectrin deficiency. These results demonstrate that a unique mechanism of human genetic disease contributes to the etiology of a third of rHS cases, facilitating diagnosis and treatment of severe anemia and identifying a new target for therapeutic manipulation.

Purpose: Pain, anxiety, depression, and other aspects of health-related quality of life (HRQoL) are important issues for people with hemophilia and caregivers of children with hemophilia. Patient-reported outcome (PRO) instruments may be used to assess aspects of HRQoL; however, the use of PROs in clinical management of patients with hemophilia is limited and inconsistent. The Bridging Hemophilia B Experiences, Results and Opportunities Into Solutions (B-HERO-S) study evaluated the impact of hemophilia B on HRQoL and other psychosocial aspects in affected adults and caregivers of children with hemophilia B. This post hoc analysis assessed correlations between PRO scores and psychosocial questions commonly asked in comprehensive care settings among B-HERO-S respondents. Patients and methods: B-HERO-S consisted of two online surveys, one administered to adults with hemophilia B (n=299) and one administered to caregivers of children with hemophilia B (n=150). The adult survey included EQ-5D-5L with visual analog scale, BPI, HAL, and PHQ-9. The caregiver survey included PHQ-9 and GAD-7. Questions related to demographics, hemophilia treatment, and psychosocial questions asked in comprehensive care visits were also included in the surveys. A post hoc analysis was performed to assess correlations between responses to selected psychosocial questions with PRO scores. Results: For adults with hemophilia B, greater pain severity and pain interference scores were associated with work-related problems, functional limitations, and relationship, psychological, and treatment issues. Significant correlations were also noted between some of these psychosocial outcomes and depressive symptoms. For caregivers, greater depression and anxiety were associated with employment issues, their child's functional, relationship, and psychological issues, having had difficulty or concerns with treatment/factor availability or affordability, and having less frequent HTC visits. Conclusion: High correlations were observed between PRO scores measuring pain, depression, and anxiety and questions commonly used in the comprehensive care setting to assess the psychosocial impact of hemophilia.

Haemophilia A carriers have historically been thought to exhibit normal haemostasis. However, recent data demonstrates that, despite normal factor VIII (FVIII), haemophilia A carriers demonstrate an increased bleeding tendency. We tested the hypothesis that obligate haemophilia carriers exhibit an increase in clinically relevant bleeding. A cross-sectional study was performed comparing haemophilia A carriers to normal women. Questionnaire assessment included a general bleeding questionnaire, condensed MCMDM-1VWD bleeding assessment tool and Pictorial Bleeding Assessment Chart (PBAC). Laboratory assessment included complete blood count, prothrombin time, activated partial thromboplastin time, fibrinogen activity, FVIII activity (FVIII:C), von Willebrand factor antigen level, ristocetin cofactor, platelet function analyser-100^TM and ABO blood type. Forty-four haemophilia A carriers and 43 controls were included. Demographic features were similar. Laboratory results demonstrated a statistically significant difference only in FVIII:C (82·5 vs. 134%, P < 0·001). Carriers reported a higher number of bleeding events, and both condensed MCMDM-1 VWD bleeding scores (5 vs. 1, P < 0·001) and PBAC scores (423 vs. 182·5, P = 0·018) were significantly higher in carriers. Haemophilia A carriers exhibit increased bleeding symptoms when compared to normal women. Further studies are necessary to fully understand the bleeding phenotype in this population and optimize clinical management.

Low von Willebrand factor (VWF) in adults is associated with significant bleeding, most notably heavy menstrual bleeding (HMB) and postpartum hemorrhage, although this has not been characterized in adolescents. The objectives of this analysis of a multicenter single arm observational cohort study in adolescents with low VWF-associated HMB were to describe the bleeding phenotype, HMB severity, and related complications. Eligibility criteria included postmenarchal females ,21 years of age with HMB (Pictorial Blood Assessment Chart [PBAC] score .100) and low VWF (2 values of VWF activity $30 and #50 IU/dL). Patients diagnosed with other bleeding disorders were ineligible. Clinical phenotype data, including PBAC and Bleeding Assessment Tool (BAT) scores, laboratory data, and HMB management/outcome details, were extracted. Patient demographics and clinical characteristics were summarized as medians with minimum/maximum values or frequencies with percentages. Groups were compared using a Wilcoxon rank-sum test or Fisher's exact test. A total of 113 patients met inclusion criteria, and 2 were excluded. Ninety four percent had a significant bleeding phenotype (BAT score .2), with predominantly mucocutaneous bleeding (32%-44%), postprocedural/surgical bleeding (15%), and severe HMB (BAT HMB domain score $2; 90%). Bleeding complications included iron deficiency (60%), anemia (21%), transfusion (12%), and hospitalization (10%). Desmopressin challenge response in subjects tested was good and sustained. Several (48%) required combined therapy for HMB (hormonal/hemostatic), and one third did not show improvement despite therapy. Our results suggest that adolescent females with low VWF have a significant bleeding phenotype and resultant complications warranting a focus on prompt diagnosis, appropriate therapy, and prevention of complications.

Introduction: Emicizumab promotes effective haemostasis in people with haemophilia A (PwHA). It is indicated for routine prophylaxis of bleeding episodes in PwHA with or without factor (F)VIII inhibitors. Aim: To investigate the effect of emicizumab dose up-titration in PwHA with suboptimal bleeding control. Methods: Data from seven completed or ongoing phase III studies were pooled. Pharmacokinetics, pharmacodynamics and bleeding events were evaluated before and after dose up-titration. Adverse events (AEs) were compared between PwHA with and without dose up-titration. Results: Of 675 PwHA evaluable for the analysis, 24 (3.6%) had their maintenance dose up-titrated to 3 mg/kg once weekly (QW). Two participants had neutralising antibodies (nAbs) associated with decreased emicizumab exposure, and dose increase did not compensate for the effect of nAbs. In the other 22 participants, mean emicizumab steady-state trough concentrations increased from 44.0 to 86.2 μg/mL after up-titration. The median (interquartile range [IQR]) efficacy period prior to up-titration was 24.6 (24.0–32.0) weeks. The model-based annualised bleed rate for ‘treated bleeds’ and ‘all bleeds’ decreased by 70.2% and 72.9%, respectively, after a median (IQR) follow-up of 97.1 (48.4–123.3) weeks in the up-titration period. Incidences of injection-site reactions and serious AEs were higher in PwHA with up-titration; however, this was already observed in these participants before the dose up-titration. Overall, the safety profile appeared similar between PwHA with and without up-titration. Conclusion: The dose up-titration to 3 mg/kg QW was well tolerated. Bleed control improved in most participants whose bleeding tendency was inadequately controlled during clinical trials.

Thrombin plays an essential role in achieving and maintaining effective hemostasis and stable clot formation. In people with hemophilia, deficiency of procoagulant factor (F)VIII or FIX results in insufficient thrombin generation, leading to reduced clot stability and various bleeding manifestations. A correlation has been found between the bleeding phenotype of people with hemophilia and the extent of thrombin generation, with individuals with increased thrombin generation being protected from bleeding and those with lower thrombin generation having increased bleeding tendency. The amount, location, and timing of thrombin generation have been found to affect the formation and stability of the resulting clot. The goal of all therapies for hemophilia is to enhance the generation of thrombin with the aim of restoring effective hemostasis and preventing or controlling bleeding; current treatment approaches rely on either replacing or mimicking the missing procoagulant (ie, FVIII or FIX) or rebalancing hemostasis through lowering natural anticoagulants, such as antithrombin. Global coagulation assays, such as the thrombin generation assay, may help guide the overall management of hemostasis by measuring and monitoring the hemostatic potential of patients and, thus, assessing the efficacy of treatment in people with hemophilia. Nevertheless, standardization of the thrombin generation assay is needed before it can be adopted in routine clinical practice.