Unravelling the effect of blood group on FVIII:C levels and response to DDAVP in 20 males with a single genotype (Twillingate Variant) causing Haemophilia A.

INTRODUCTION: The genetic variant responsible for haemophilia A (HA) significantly impacts endogenous coagulant factor VIII (FVIII:C) level, thus impacting DDAVP responsiveness. Blood group (BG) also impacts FVIII:C levels, but this is difficult to evaluate in a genetically heterogeneous population. Canada has a large cohort of mild-moderate HA due to a single point variant: c.6104T>C, p.Val2035Ala-the Twillingate variant. AIM: To evaluate the impact of BG on endogenous FVIII:C levels and DDAVP responsiveness in a single genotype of mild-moderate HA. METHODS: This was a retrospective, single-centre study. BG and FVIII:C levels were obtained for males with the Twillingate variant. One-hour absolute and fold increases in FVIII:C post-DDAVP were calculated. T-tests and Mann-Whitney U tests were used to compare FVIII:C levels and DDAVP challenge variables between individuals according to BGs (O vs. non-O). RESULTS: Twenty males were included. There were significant differences between BGs (O vs. non-O) in their lowest FVIII:C level at age <12 years (medians: 0.05 vs. 0.08 IU/mL; P = .05). Fifteen subjects underwent DDAVP challenges. Mean 1-h FVIII:C were 0.29 (O BG) versus 0.41 IU/mL (non-O BG); P = .04. There were no significant differences between BGs (O vs. non-O) in mean absolute FVIII:C increase (0.20 vs. 0.27 IU/mL; P = .10) and FVIII:C fold increase (3.3-fold vs. 3.8-fold; P = .51). CONCLUSION: In HA subjects with an identical genotype, BG significantly impacts baseline FVIII:C levels and FVIII:C levels post-DDAVP, but does not impact absolute and fold increases in FVIII:C with DDAVP.

Thromboelastography and thrombin generation assessments for pediatric severe hemophilia A patients are highly variable and not predictive of clinical phenotypes.

Background: Severe hemophilia A (SHA) patients vary in severity of bleeding, arthropathy, and requirements for replacement factor VIII (FVIII). Baseline hemostatic activity assays using calibrated automated thrombography (CAT) and thromboelastography (TEG) may offer insights into the physiological basis of clinical heterogeneity. Objectives: Use CAT and TEG to measure baseline hemostatic activity in a cohort of 30 pediatric SHA patients with available clinical data. Determine effect of contact activation inhibition with corn trypsin inhibitor (CTI). Assess heterogeneity among patients for baseline hemostatic activity and examine correlations between assay results and clinical parameters including FVIII dosing regimen, von Willebrand factor level, and Pettersson arthropathy score. Methods: SHA blood after FVIII washout was subjected to TEG, and platelet-rich (PRP) and platelet-poor plasma was used for CAT assays. Varying concentrations of tissue factor (TF) were used. Statistical analysis examined relationships between assay results, and clinical parameters. Results: CTI treatment was required to obtain TEG and CAT results representative of baseline hemostatic activity. Weak activity was observed in assays with low TF concentrations (0.5-2 pM), and most but not all samples approached normal activity levels at high TF concentrations (10-20 pM). A significant positive correlation was observed between results of TEG and CAT-PRP assays. Correlations were not detected between hemostatic assay results and clinical parameters. Conclusions: In vitro hemostatic assay results of samples containing platelets showed concordance. Assay results were not predictive of FVIII requirements or correlated with other clinical parameters. SHA patient heterogeneity is influenced by factors other than baseline hemostatic activity.

Sexual issues in people with haemophilia: Awareness and strategies for overcoming communication barriers.

INTRODUCTION: The Haemophilia Experiences, Results and Opportunities (HERO) Study identified sexual health as an important psychosocial issue affecting people with haemophilia (PWH) worldwide. However, sexual health is inadequately addressed at haemophilia treatment centres (HTCs), because PWH and healthcare professionals (HCPs) experience barriers to broaching the subject. There is a clear need for HCP training to support communication in this area and improve comprehensive care. AIM: The Sexual Health: Strategies for Effective Communication pilot programme was trialled in Canada to assess HCP readiness and ability to discuss sexual health issues with PWH and test communication tools to facilitate these conversations. METHODS: The pilot programme consisted of two 3-h sessions attended by seven HCPs from Calgary's Alberta Children's and Foothills Hospitals. The sessions included lectures and case scenarios and explained the check-in-affirm-clarify-answer and head-heart-body tools designed by the Centre for Sexuality to aid communication. The pilot was evaluated through discussions and an online questionnaire. RESULTS: The pilot was well received by all HCP participants. Questionnaire data showed improvements in participants' knowledge, skills and comfort level in conducting sexual health discussions. Greatest improvements were noted in knowledge (100% 'good' or 'excellent' after the pilot, compared with 29% beforehand). Importantly, 86% felt that the material presented would be applicable in clinical practice. CONCLUSION: The Canadian pilot demonstrated the effectiveness of the proposed educational programme. The underlying principles could be adapted to similar programmes for other HTCs to facilitate sexual health discussions.

Hemophilia prophylaxis adherence and bleeding using a tailored, frequency-escalated approach: The Canadian Hemophilia Primary Prophylaxis Study.

BACKGROUND: Standard of care for persons with severe hemophilia A includes regular replacement of factor VIII (FVIII). Prophylaxis regimens using standard half-life (SHL) FVIII concentrates, while effective, are costly and require frequent intravenous infusions. AIM: This study evaluated the adherence of 56 boys with severe hemophilia A to tailored, frequency-escalated prophylaxis with an SHL recombinant FVIII concentrate. METHODS: We reviewed the factor infusion and bleeding logs of study subjects. Adherence to the prescribed regimen was calculated on a weekly basis, and bleeding rates were determined from self/proxy-reported bleeding logs. The primary outcome was adherence to the prescribed prophylaxis regimen. RESULTS: The median (range of values [ROV]) weekly adherence to prophylaxis was 85.7% (37.4%-99.8%). The median (ROV) adherent weeks on steps 1 (weekly), 2 (twice weekly), and 3 (alternate-day) were 92.9% (50%-100%), 80.3 (32%-96%), and 72.6% (14%-98%); relative to step 1, subjects were less likely to be adherent on steps 2 and 3 (P < 0.00). On step 1, our cohort had higher adherence than previously reported rates. The median (ROV) adherence to the breakthrough bleeding protocol was 47.1% (0%-100%). At any given time, bleeding risk was reduced by 15% for each 10% increase in adherence during the preceding 12 weeks (hazard ratio, 0.85; 95% confidence interval, 0.81-0.90). CONCLUSION: This cohort had high rates of adherence to the prescribed prophylaxis regimen. Initiating prophylaxis with once-weekly infusions facilitated adherence to the prophylaxis regimen in this cohort of boys with severe hemophilia A started on primary prophylaxis at a very young age.

Increased burden on caregivers of having a child with haemophilia complicated by inhibitors.

INTRODUCTION: Having a child with a chronic disease often increases the burden in the family with more hospital visits, treatment administration, and increased worries for the ill child. A cross-sectional, international, multi-centre study in caregivers of children <18 years with haemophilia and inhibitor was performed at Haemophilia Treatment Centres in Sweden, UK, and Canada to evaluate caregivers' burden and their health-related quality of life (HRQoL) compared to that of caregivers of children on prophylaxis without inhibitors and caregivers of healthy children. METHODS: Caregivers of children with haemophilia completed several questionnaires (SF-36, Visual Analogue Scale of Interference (VAS), Caregivers' Burden Scale and Impact on Family Scale (IOF). Caregivers of healthy children completed only the SF-36. In addition, socio-demographic data were collected. RESULTS: In total, 143 caregivers were included in the study. Comparing the two haemophilia groups with caregivers of healthy children revealed significant differences for all SF-34 domains except 'pain' and 'general health'. In Caregivers' Burden Scale, caregivers of children with inhibitors reported higher impact of haemophilia (P < 0.0001) and higher impact on VAS (P < 0.0001) compared to caregivers of children without inhibitors. In IOF, caregivers of children with inhibitors reported significant negative impact of the disease, except for aspect of coping. CONCLUSION: Caregivers of children with inhibitors reported higher impact of the disease compared to caregivers of children with no inhibitors. No differences between mothers and fathers in the two groups for SF-36, Caregivers' Burden Scale, VAS and IOF, except for domain pain in SF-36 where mothers reported higher impairments.

Therapeutic consequences for misdiagnosis of type 2N von Willebrand disease.

Patients presenting with a low FVIII:C and with normal VWF levels are usually presumed to have hemophilia (males) or be carriers for hemophilia (females). Some of these patients may instead have VWD:2N. Such patients if misdiagnosed are likely to suffer from insufficiently treated bleeds. We report 2 males and 1 female who presented with a low FVIII:C (1-21%) and minimally reduced/normal VWF and were assumed to have, or be a carrier for, hemophilia A. Eventually all were found to have VWD:2N. Prior to the correct diagnosis the males had been treated with rFVIII with poor responses and ultimately adverse clinical consequences.

Clinical and cost implications of target joints in Canadian boys with severe hemophilia A.

OBJECTIVE: To compare target joint-associated costs incurred by boys with severe hemophilia A 1 year before and 1 year after development of a target joint (pre-TJ, post-TJ). STUDY DESIGN: Resource utilization data were extracted retrospectively from medical and hemophilia clinic charts and patient diaries for 16 boys attending the Hospital for Sick Children (HSC)'s comprehensive care hemophilia program. Resources examined included drugs, medical care, hospitalization, laboratory tests, therapies, and transfusions received. All costs were figured using standard price lists and were discounted using an annual rate of 3%. RESULTS: Fifteen of the 16 boys developed at least one target joint, defined as three bleeds into any single joint within a consecutive 3-month period, at an average age of 54 months (range, 15-94 months), with ankles being most often affected, followed by elbows and knees (46% vs 28% and 23%, respectively). The total cost of treating a boy with on-demand Factor VIII (FVIII) increased by 119% after development of a target joint, from $20,091 (in 2002 Canadian dollars [$CDN]) in the year before to $43,890 in the year after target joint development. Factor VIII use accounted for 87% of the total cost in the year before target joint development and 93% in the year after. CONCLUSIONS: This study identified substantial increased costs of care associated with target joint development. This finding provides further support for more aggressive treatment aimed at reducing target joints-either more aggressive treatment of joint bleeds or institution of primary prophylactic therapy at an early age.

Effect of intracranial bleeds on the health and quality of life of boys with hemophilia.

OBJECTIVES: To compare the health, physical function, and quality of life (QoL) of boys with hemophilia with and without a history of intracranial hemorrhage (ICH). STUDY DESIGN: Of 172 patients with hemophilia A or B, 18 (10%) had at least one episode of ICH. For outcome assessments, 16 of 18 (89%) boys with ICH and 32 controls, matched (1:2) for age and severity of hemophilia, were available. The outcome measures were neurologic function, physical function, and QoL. RESULTS: The median age of the boys at the first ICH was 5.9 months (range, 1 day to 2.7 years). Boys with ICH had a higher incidence of inhibitors and lower mean household income. Neurologic examination was abnormal in seven of 16 (44%) boys with ICH and nine of 32 (28%) controls (P=.3). The mean physical function in boys with ICH was lower (82%+/-25%) compared with controls (93.5%+/-12%, P=.045). The QoL was decreased in boys with ICH compared with controls (6.8+/-3.2 vs 8.5+/-1.4, P=.02), whereas health-related QoL was not significantly different between groups. CONCLUSION: The poorer long-term outcomes of boys with hemophilia appropriately treated for ICH, especially in the domain of QoL, suggest that new strategies to prevent ICH and to manage ICH effectively in this population are needed.

DDAVP challenge tests in boys with mild/moderate haemophilia A.

Desmopressin (DDAVP) increases plasma factor VIII coagulant activity (FVIII:C) levels in patients with mild/moderate haemophilia A. In some subjects, FVIII can be increased to haemostatic levels, thereby avoiding use of factor VIII concentrates. We reviewed our hospital's experience with 62 boys with FVIII:C levels 0.01-0.3 IU/ml who had a DDAVP challenge test (i.v. 0.3 microg/kg) following diagnosis. A therapeutic response was defined as a 1 h post-FVIII:C increase at least twofold over baseline and > 0.3 IU/ml. Of the total group, 29 (47%) boys responded to DDAVP, all of them with mild haemophilia (baseline FVIII:C > or = 0.05 IU/ml), yielding a response rate of 57% in this subgroup. Boys who responded to DDAVP had higher baseline FVIII:C levels (mean +/- SEM, 0.17 +/- 0.01 vs 0.10 +/- 0.01 IU/ml, P < 0.01) and were older (5.2 +/- 0.8 vs 3 +/- 0.4 years, P = 0.02) than those who failed to do so. The association between DDAVP response and age, however, remains unclear: seven boys who failed the initial challenge test responded to re-challenge after a mean of 6.3 years (median 4.9, range 0.5-12.5), increasing the response rate in boys with mild haemophilia to 71%. Age and FVIII:C association with DDAVP response are both important in boys with mild/moderate haemophilia A. Absence of response to DDAVP should therefore be confirmed by later re-challenge.