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Background: Desmopressin is frequently used perioperatively in persons with nonsevere hemophilia A. However, increase in factor (F)VIII:C after desmopressin use is interindividually highly variable. Tachyphylaxis has only been reported in test setting for persons with hemophilia A, with a remaining response of approximately 70% after a second dose compared with that after a first dose., Objectives: To study tachyphylaxis of FVIII:C response after multiple administration(s) of desmopressin in perioperative persons with nonsevere hemophilia A., Methods: We studied FVIII:C levels after desmopressin before (day 0 [D0]) and on days 1 (D1) and 2 (D2) after surgery in 26 patients of the DAVID and Little DAVID studies. We studied tachyphylaxis by comparing the responses at D1 and D2 with that at D0. We also assessed the reproducibility of the D0 response in comparison to an earlier performed desmopressin test., Results: The median absolute FVIII:C increase was 0.50 IU/mL (0.35-0.74; n  = 23) at D0, 0.21 IU/mL (0.14-0.28; n  = 17) at D1, and 0.23 IU/mL (0.16-0.30; n  = 11) at D2. The median percentage of FVIII increase after the second administration (D1) compared with the first (D0) was 42.9% (29.2%-52.5%; n  = 17) and that of the third (D2) compared with the first (D0) was 36.4% (23.7%-46.9%; n  = 11). The FVIII:C desmopressin response at D0 was comparable with the desmopressin test response in 74% of the patients., Conclusion: Tachyphylaxis in the surgical setting was considerably more pronounced than previously reported, with FVIII:C at D1 and D2 of 36% to 43% of the initial response. Our results may have important implications for monitoring repeated desmopressin treatment when used perioperatively., (© 2024 The Authors.)

Background: To provide insight into the perspectives of children and young adults with transfusion-dependent thalassemia and sickle cell disease and their caregivers regarding the decision for hematopoietic stem cell transplantation (HSCT)., Procedure: A qualitative longitudinal multicenter study. Data collection consisted of 40 audio-recorded conversations between physicians and families and 77 interviews with patients and/or caregivers related to 27 unique cases, collected at different time points throughout the decision-making process., Results: Conversations and interviews revealed "hoping for a normal life" as an overarching theme, consisting of four main topics: (i) "Building a frame of reference" refers to a process where patients or families try to obtain comprehensive information on HSCT and translate this to their situation to decide. (ii) "Balancing between loss and benefit" reports the process of considering the advantages and disadvantages of continuing with supportive care to treat their disease versus choosing HSCT. (iii) "Experiencing the impact of HSCT" describes the impactfull experience of the HSCT period by those who chose HSCT. (iv) "Balancing again" refers to reflecting on the decision made., Conclusions: The hope for a normal life guided the decision-making process, described as a constant balance between the impact of the disease and HSCT. A structured approach to explore patients' and caregivers' perspectives on HSCT decision-making is needed, where specifically discussing the impact of the disease and hope for a normal life need to be integrated in the process., (© 2023 The Authors. Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

Purpose: Hemophilia B is a bleeding disorder, caused by a factor IX (FIX) deficiency. Recently, FIX concentrates with extended half-life (EHL) have become available. Prophylactic dosing of EHL-FIX concentrates can be optimized by assessment of individual pharmacokinetic (PK) parameters. To determine these parameters, limited sampling strategies (LSSs) may be applied. The study aims to establish adequate LSSs for estimating individual PK parameters of EHL-FIX concentrates using in silico evaluation., Methods: Monte Carlo simulations were performed to obtain FIX activity versus time profiles using published population PK models for N9-GP (Refixia), rFIXFc (Alprolix), and rIX-FP (Idelvion). Fourteen LSSs, containing three or four samples taken within 8 days after administration, were formulated. Bayesian analysis was applied to obtain estimates for clearance (CL), half-life (t 1/2 ), time to 1% (Time 1% ), and calculated weekly dose (Dose 1% ). Bias and precision of these estimates were assessed to determine which LSS was adequate., Results: For all PK parameters of N9-GP, rFIXFc and rIX-FP bias was generally acceptable (range: -5% to 5%). For N9-GP, precision of all parameters for all LSSs was acceptable (< 25%). For rFIXFc, precision was acceptable for CL and Time 1% , except for t 1/2 (range: 27.1% to 44.7%) and Dose 1% (range: 12% to 29.4%). For rIX-FP, all LSSs showed acceptable bias and precision, except for Dose 1% using LSS with the last sample taken on day 3 (LSS 6 and 10)., Conclusion: Best performing LSSs were LSS with samples taken at days 1, 5, 7, and 8 (N9-GP and rFIXFc) and at days 1, 4, 6, and 8 (rIX-FP), respectively., (© 2021. The Author(s).)

Purpose: Pharmacokinetic (PK) differences between the extended half-life (EHL) factor IX (FIX) concentrates for hemophilia B exist, which may influence hemostatic efficacy of replacement therapy in patients. Therefore, we aimed to evaluate the PK properties of three EHL-FIX concentrates and compare them to a standard half-life (SHL) recombinant FIX (rFIX) concentrate., Methods: Activity-time profiles of PEGylated FIX (N9-GP), FIX linked with human albumin (rIX-FP), FIX coupled to human IgG1 Fc-domain (rFIXFc), and SHL rFIX were simulated for 10,000 patients during steady-state dosing of 40 IU/kg once weekly (EHL-FIX) and biweekly (rFIX) using published concentrate specific population PK models., Results: Half-lives were respectively 80, 104, and 82 h for N9-GP, rIX-FP, and rFIXFc versus 22 h for rFIX. Between the EHL concentrates, exposure was different with area under the curve (AUC) values of 78.5, 49.6, and 12.1 IU/h/mL and time above FIX target values of 0.10 IU/mL of 168, 168, and 36 h for N9-GP, rIX-FP, and rFIXFc, respectively. N9-GP produced the highest median in vivo recovery value (1.70 IU/dL per IU/kg) compared with 1.18, 1.00, and 1.05 IU/dL per IU/kg for rIX-FP, rFIXFc, and rFIX, respectively., Conclusions: When comparing EHL products, not only half-life but also exposure must be considered. In addition, variation in extravascular distribution of the FIX concentrates must be taken into account. This study provides insight into the different PK properties of these concentrates and may aid in determination of dosing regimens of EHL-FIX concentrates in real-life., (© 2021. The Author(s).)

Background: In recent years, more awareness is raised about sex-specific dilemmas in inherited bleeding disorders. However, no large studies have been performed to assess differences in diagnosis, bleeding phenotype and management of men and women with bleeding disorders. Therefore, we investigated sex differences in a large cohort of well-defined patients with autosomal inherited bleeding disorders (von Willebrand disease (VWD), rare bleeding disorders (RBDs) and congenital platelet defects (CPDs))., Methods: We included patients from three nationwide cross-sectional studies on VWD, RBDs and CPDs in the Netherlands, respectively the WiN, RBiN and TiN study. In all studies a bleeding score (BS) was obtained, and patients filled in an extensive questionnaire on the management and burden of their disorder., Findings: We included 1092 patients (834 VWD; 196 RBD; 62 CPD), of whom 665 (60.9%) were women. Women were more often referred because of a bleeding diathesis than men (47.9% vs 36.6%, p  = 0.002). Age of first bleeding was similar between men and women, respectively 8.9 ± 13.6 (mean ±sd) years and 10.6 ± 11.3 years ( p  = 0.075). However, the diagnostic delay, which was defined as time from first bleeding to diagnosis, was longer in women (11.6 ± 16.4 years) than men (7.7 ± 16.6 years, p  = 0.002). Similar results were found when patients referred for bleeding were analyzed separately. Of women aging 12 years or older, 469 (77.1%) had received treatment because of sex-specific bleeding., Interpretation: Women with autosomal inherited bleeding disorders are more often referred for bleeding, have a longer diagnostic delay, and often require treatment because of sex-specific bleeding., Funding: The WiN study was supported (in part) by research funding from the Dutch Hemophilia Foundation (Stichting Haemophilia), Shire (Takeda), and CSL Behring (unrestricted grant)., Competing Interests: F. Atiq received the CSL Behring-professor Heimburger Award 2018 and a travel grant from Sobi. J.L. Saes and S.E.M. Schols received travel support from Bayer, Takeda and Sobi. F.W.G. Leebeek received research support from CSL Behring and Shire/Takeda for performing the Willebrand in the Netherlands (WiN) study, and from UniQure and Sobi for other studies. He is consultant for UniQure, Novo Nordisk, BioMarin and Shire/Takeda, of which the fees go to the institution, and has received a travel grant from Sobi. He is also a DSMB member for a study by Roche. H.C.J. Eikenboom received research support from CSL Behring and he has been a teacher on educational activities of Roche. K.P.M. van Galen received unrestricted research support from CSL Behring and Bayer and speakers fee from Takeda, CSL Behring and Bayer. J.G. van der Bom has been a teacher on educational activities of Bayer. M.H. Cnossen has received grants from governmental research institutes, such as the Dutch Research institute (NOW), ZonMW, Innovation fund, NWO-NWA and unrestricted investigator initiated research grants as well as educational and travel funding from various companies over the years (Pfizer, Baxter/Baxalta/Shire, Bayer Schering Pharma, CSL Behring, Sobi Biogen, novo Nordisk, Novartis and Nordic Pharma), and has served as a member on steering boards of Roche and Bayer. All grants, awards and fees go to the Erasmus MC as an institution. The institution of K. Fijnvandraat has received unrestricted research grants from CSL Behring, Sobi and NovoNordisk and her institution received consultancy fees from Grifols, Takeda, Novo Nordisk and Roche. K. Meijer received research support from Bayer, Sanquin and Pfizer; speaker fees from Bayer, Sanquin, Boehringer Ingelheim, BMS and Aspen; consulting fees from Uniqure, of which all fees go to the institution. B.A.P. Laros‐van Gorkom has received unrestricted educational grants from Baxter and CSL Behring. M.J.H.A. Kruip received grants from governmental research institutes, such as the Dutch Research institute (ZonMW/NWO), Dutch Thrombosis Foundation, Innovation fund, unrestricted grants from Bayer, Pfizer, Daiichi Sankyo, Sobi and Boehringer Ingelheim and speakers fee from Bayer. R.E.G. Schutgens received grants from Bayer, grants from Baxalta, Pfizer, NovoNordisk. The institution of M. Peters received an unrestricted research grant from Pfizer. F.J.M. van der Meer received grants from CSL Behring, Pfizer, Bayer, Novo Nordisk, Sobi, Roche, and OctaPharma. W.L. van Heerde reports speaker and consultant and travel fees from Takeda, Bayer, CSL Behring, and Sobi. He is also founder and co-owner of Enzyre. None of the other authors has a conflict of interest to declare., (© 2021 The Authors.)

Background: Patients with hemophilia B are increasingly treated with extended half-life (EHL) factor IX (FIX) concentrates. For the laboratory, introduction of these EHL concentrates presents a major challenge. To understand the variation in FIX activity levels, all available diagnostic assays need to be directly compared., Methods: The ECAT, UKNEQAS, and RCPAQAP have collaboratively performed a global survey to evaluate the quality of FIX measurements using FIX deficient plasma samples spiked with recombinant FIX (rFIX), rFIXFP, rFIXFc, and N9-GP to levels at typical FIX trough (6 IU/dL) and peak levels (60 IU/dL). Participants were asked to use their routine protocols, using one-stage assays (OSA) or chromogenic assays (CA)., Results: In samples spiked with 6 IU/dL product, median (25%-75% range) FIX activity levels (OSA), were 8.0 IU/dL (7.0-9.2) for rFIX, 6.0 IU/dL (4.0-7.1) for rFIXFP, 6.6 IU/dL (5.5-8.0) for rFIXFc, and 4.9 IU/dL (3.5-8.4) for N9-GP. In samples spiked with 60 IU/dL, FIX activity levels measured (using OSA) was 63.0 IU/dL (59.9-67.0) for rFIX, 42.5 IU/dL (28.2-47.0) for rFIXFP, 50.0 IU/dL (45.0-55.0) for rFIXFc, and 34.0 IU/dL (24.8-67.5) for N9-GP. Considerable differences were observed between reagents for all samples. With CA, there was also quite some variation, but no differences between reagents., Conclusion: Large variation is observed in the measurement of FIX activity levels after administration of rFIX and EHL FIX products. For N9-GP, most silica-based assays show especially high levels. It is essential to standardize and improve reliability of measurements of these concentrates as diagnosis and treatment monitoring is based on these results., (© 2020 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals LLC on behalf of International Society on Thrombosis and Haemostasis.)

Inhibitor development is a major complication of treatment with factor VIII concentrates in nonsevere haemophilia A. It has been suggested that plasma-derived factor VIII (FVIII) concentrates elicit fewer inhibitors than recombinant FVIII concentrates, but studies in severe haemophilia A patients have shown conflicting results. We designed a case-control study to investigate the clinical and genetic risk factors for inhibitor development in nonsevere haemophilia A patients. We investigated whether the type of FVIII concentrate was associated with inhibitor development in nonsevere haemophilia A patients. This nested case-control study includes 75 inhibitor patients and 223 controls, from a source population of the INSIGHT study, including all nonsevere haemophilia A patients (FVIII:C 2-40%) that were treated with FVIII concentrates in 33 European and one Australian centre. Cases and controls were matched for date of birth and cumulative number of exposure days (CED) to FVIII concentrate. A conditional logistic regression model was used to calculate unadjusted and adjusted odds ratios. No increased risk for inhibitor development was found for any type of FVIII concentrate; either when comparing recombinant FVIII concentrates to plasma-derived FVIII concentrates (adjusted odds ratio 0·96, 95% confidence interval (CI) 0·36-2·52) or for specific types of FVIII concentrates., (© 2020 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Sickle cell disease is an autosomal recessive, multisystem disorder, characterised by chronic haemolytic anaemia, painful episodes of vaso-occlusion, progressive organ failure and a reduced life expectancy. Sickle cell disease is the most common monogenetic disease, with millions affected worldwide. In well-resourced countries, comprehensive care programs have increased life expectancy of sickle cell disease patients, with almost all infants surviving into adulthood. Therapeutic options for sickle cell disease patients are however, still scarce. Predictors of sickle cell disease severity and a better understanding of pathophysiology and (epi)genetic modifiers are warranted and could lead to more precise management and treatment. This review provides an extensive summary of the pathophysiology and management of sickle cell disease and encompasses the characteristics, complications and current and future treatment options of the disease., (Copyright © 2019. Published by Elsevier Ltd.)

Essentials It is unclear whether there are differences between von Willebrand factor (VWF) activity assays. We compared the four most used VWF activity assays in 661 von Willebrand disease (VWD) patients. All assays correlated excellently, but a discrepant classification was seen in 20% of patients. Differences between VWF activity assays have a large impact on the classification of VWD. SUMMARY: Background Measuring the ability of von Willebrand factor (VWF) to bind to platelets is crucial for the diagnosis and classification of von Willebrand disease (VWD). Several assays that measure this VWF activity using different principles are available, but the clinical relevance of different assay principles is unclear. Objective To compare the four most widely used VWF activity assays in a large VWD patient population. Methods We measured VWF:RCo (ristocetin to activate VWF + whole platelets), VWF:GPIbR (ristocetin + platelet glycoprotein Ib receptor [GPIb] fragments), VWF:GPIbM (gain-of-function GPIb fragments that bind VWF spontaneously without ristocetin) and VWF:Ab (monoclonal antibody directed against the GPIb binding epitope of VWF to mimic platelets) in 661 VWD patients from the nationwide 'Willebrand in the Netherlands' (WiN) Study. Results All assays correlated excellently (Pearson r > 0.9), but discrepant results led to a different classification for up to one-fifth of VWD patients. VWF:RCo was not sensitive enough to classify 18% of patients and misclassified half of genotypic 2B VWD patients, especially those with p.Arg1306Trp. VWF:GPIbR was more sensitive, accurately classified the vast majority of patients, and was unaffected by the p.Asp1472His variant that causes artificially low VWF:RCo. VWF:GPIbM was the most precise assay but misclassified over a quarter of genotypic 2A, 2B and 3 patients. VWF:Ab, often not considered an actual VWF activity assay, performed at least equally to the other assays with regard to accurate VWD classification. Conclusion Although the different VWF activity assays are often considered similar, differences between assays have a large impact on the classification of VWD., (© 2018 International Society on Thrombosis and Haemostasis.)

Essentials Factor IX (FIX) dosing using body weight frequently results in under and overdosing during surgery. We aimed to establish a population pharmacokinetic (PK) model describing the perioperative FIX levels. Population PK parameter values for clearance and V1 were 284 mL h -1 70 kg -1 and 5450 mL70 kg -1 . Perioperative PK parameters differ from those during non-surgical prophylactic treatment. SUMMARY: Background Hemophilia B is a bleeding disorder characterized by a deficiency of coagulation factor IX (FIX). In the perioperative setting, patients receive FIX concentrates to ensure hemostasis. Although FIX is usually dosed according to bodyweight, under- and overdosing occurs frequently during surgery. Aim The objective was to quantify and explain the interpatient variability of perioperatively administered plasma-derived (pd) and recombinant (r) FIX concentrates. Methods Data were collected from 118 patients (median age, 40 years [range, 0.2-90]; weight, 79 kg [range, 5.3-132]) with moderate (28%) or severe hemophilia B (72%), undergoing 255 surgical procedures. Population pharmacokinetic (PK) parameters were estimated using nonlinear mixed-effect modeling in NONMEM. Results Measured perioperative FIX level vs. time profiles were adequately described using a three-compartment PK model. For a typical 34-year-old patient receiving rFIX, clearance (CL), intercompartmental clearance (Q2, Q3), distribution volume of the central compartment (V1) and peripheral compartments (V2, V3) plus interpatient variability (%CV) were: CL, 284 mL h -1 70 kg -1 (18%); V1, 5450 mL70 kg -1 (19%); Q2, 110 mL h -1 70 kg -1 ; V2, 4800 mL70 kg -1 ; Q3, 1610 mL h -1 70 kg -1 ; V3, 2040 mL70 kg -1 . From 0.2 years, CL and V1 decreased 0.89% and 1.15% per year, respectively, until the age of 34 years. Patients receiving pdFIX exhibited a lower CL (11%) and V1 (17%) than patients receiving rFIX. Interpatient variability was successfully quantified and explained. Conclusions The estimated perioperative PK parameters of both pdFIX and rFIX are different from those reported for prophylactic treatment. The developed model may be used to apply PK-guided dosing of FIX concentrates during surgery., (© 2018 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.)

Introduction: While the number of trauma patients surviving their injury increase, it is important to measure Quality of Life (QoL). The Abbreviated World Health Organization Quality of Life (WHOQOL-BREF) questionnaire can be used to assess QoL. However, its psychometric properties in trauma patients are unknown and therefore, we aimed to investigate the validity and reliability of the WHOQOL-BREF for the hospitalized trauma population., Methods: Data were derived from the Brabant Injury Outcome Surveillance. Floor and ceiling effects and missing values of the WHOQOL-BREF were examined. Confirmatory factor analysis (CFA) was performed to examine the underlying 4 dimensions (i.e. physical, psychological, social and environmental) of the questionnaire. Cronbach's alpha (CA) was calculated to determine internal consistency. In total, 42 hypotheses were formulated to determine construct validity and 6 hypotheses were created to determine discriminant validity. To determine construct validity, Spearman's correlations were calculated between the WHOQOL-BREF and the EuroQol-five-dimension-3-level questionnaire, the Health Utility Index Mark 2 and 3, the Hospital Anxiety and Depression Scale and the Impact of Event Scale. Discriminant validity between patients with minor injuries (i.e. Injury Severity Score (ISS)≤8) and moderate/severe injuries (i.e. ISS ≥ 9) was examined by conducting Mann-Whitney-U-tests., Results: In total, 202 patients (median 63y) participated in this study with a median of 32 days (interquartile range 29-37) post-trauma. The WHOQOL-BREF showed no problematic floor and ceiling effects. The CFA revealed a moderate model fit. The domains showed good internal consistency, with the exception of the social domain. All individual items and domain scores of the WHOQOL-BREF showed nearly symmetrical distributions since mean scores were close to median scores, except of the 'general health' item. The highest percentage of missing values was found on the 'sexual activity' item (i.e. 19.3%). The WHOQOL-BREF showed moderate construct and discriminant validity since in both cases, 67% of the hypotheses were confirmed., Conclusion: The present study provides support for using the WHOQOL-BREF for the hospitalized trauma population since the questionnaire appears to be valid and reliable. The WHOQOL-BREF can be used to assess QoL in a heterogeneous group of hospitalized trauma patients accurately., Trail Registration: ClinicalTrials.gov identifier: NCT02508675., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Replacement therapy with clotting factor concentrates (CFC) is the mainstay of treatment in hemophilia. Its widespread application has led to a dramatic decrease in morbidity and mortality in patients, with concomitant improvement of quality of life. However, dosing is challenging and costs are high. This review discusses benefits and limitations of pharmacokinetic (PK)-guided dosing of replacement therapy as an alternative for current dosing regimens. Dosing of CFC is now primarily based on body weight and based on its in vivo recovery (IVR). Benefits of PK-guided dosing include individualization of treatment with better targeting, more flexible blood sampling, increased insight into association of coagulation factor levels and bleeding, and potential overall lowering of overall costs. Limitations include a slight burden for the patient, and availability of closely collaborating, experienced clinical pharmacologists., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: Haemophilia B is caused by a deficiency of coagulation factor IX (FIX) and characterized by bleeding in muscles and joints. In the perioperative setting, patients are treated with FIX replacement therapy to secure haemostasis. Targeting of specified FIX levels is challenging and requires frequent monitoring and adjustment of therapy., Aim: To evaluate perioperative management in haemophilia B, including monitoring of FIX infusions and observed FIX levels, whereby predictors of low and high FIX levels were assessed., Methods: In this international multicentre study, haemophilia B patients with FIX < 0.05 IU mL -1 undergoing elective, minor or major surgical procedures between 2000 and 2015 were included. Data were collected on patient, surgical and treatment characteristics. Observed FIX levels were compared to target levels as recommended by guidelines., Results: A total of 255 surgical procedures were performed in 118 patients (median age 40 years, median body weight 79 kg). Sixty percent of FIX levels within 24 hours of surgery were below target with a median difference of 0.22 IU mL -1 [IQR 0.12-0.36]; while >6 days after surgery, 59% of FIX levels were above target with a median difference of 0.19 IU mL -1 [IQR 0.10-0.39]. Clinically relevant bleeding complications (necessity of a second surgical intervention or red blood cell transfusion) occurred in 7 procedures (2.7%)., Conclusion: This study demonstrates that targeting of FIX levels in the perioperative setting is complex and suboptimal, but although this bleeding is minimal. Alternative dosing strategies taking patient and surgical characteristics as well as pharmacokinetic principles into account may help to optimize and individualize treatment., (© 2018 The Authors. Haemophilia Published by John Wiley & Sons Ltd.)

Background: ED overcrowding is an increasing problem worldwide that may negatively affect quality of care and patient outcomes. We aimed to study ED overcrowding across European centres., Methods: Questionnaires on structure and process of care, including crowding, were distributed to 68 centres participating in a large European study on traumatic brain injury (Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury)., Results: Of the 65 centres included in the analysis, 32 (49%) indicated that overcrowding was a frequent problem and 28 (43%) reported that patients were placed in hallways 'multiple times a day'; 27 (41%) stated that multiple times a day, there was no bed available when a patient needed to be admitted. Ambulance diversion rarely occurred in the participating centres., Conclusion: Similar to reports from other parts of the world, ED crowding appears to be a considerable problem in Europe. More research is needed to determine effective ways to reduce overcrowding., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Extended half-life proteins (EHL) are increasingly used in clinical practice, but there is no standardized approach to sampling, interpretation and implementation of pharmacokinetics (PK) data to maximize treatment benefit. The goal of EHL treatment is to attain a trough level sufficient to protect against spontaneous bleeds and reduce infusion frequency and limitations on individual activity and lifestyle. Performing classical PK assessments requires multiple blood samples, which is burdensome for patients and providers. Herein we review a population pharmacokinetic (popPK) approach to estimate individual PK parameters to transition patients from standard half-life (SHL) to EHL concentrates. We propose that a minimum of two to four post-infusion samples is sufficient to estimate individual PK profiles, with sufficient certainty to maintain factor levels above 1% and achieve bleed-free lifestyles. We also survey current PK use in patients transitioning to EHL, review key PK parameters and popPK models, and recommend an approach to using PK in patients initiating or switching to EHL., (© 2018 International Society on Thrombosis and Haemostasis.)

Objectives: In a separate document, we have provided specific guidance on performing individual pharmacokinetic (PK) studies using limited samples in persons with hemophilia with the goal to optimize prophylaxis with clotting factor concentrates. This paper, intended for clinicians, aims to describe how to interpret and apply PK properties obtained in persons with hemophilia., Methods: The members of the Working Party on population PK (PopPK) of the ISTH SSC Subcommittee on Factor VIII and IX and rare bleeding disorders, together with additional hemophilia and PK experts, completed a survey and ranking exercise whereby key areas of interest in the field were identified. The group had regular web conferences to refine the manuscript's scope and structure, taking into account comments from the external feedback to the earlier document., Results: Many clinical decisions in hemophilia are based on some form of explicit or implicit PK assessment. Individual patient PK profiles can be analyzed through traditional or PopPK methods, with the latter providing the advantage of fewer samples needing to be collected on any prophylaxis regimen, and without the need the for a washout period. The most useful presentation of PK results for clinical decision making are a curve of the factor activity level over time, the time to achieve a certain activity level, or related parameters like half-life or exposure (AUC). Software platforms have been developed to deliver this information to clinicians at the point of care. Key characteristics of studies measuring average PK parameters were reviewed, outlining what makes a credible head-to-head comparison among different concentrates. Large data collections of PK and treatment outcomes currently ongoing will advance care in the future., Conclusions: Traditionally used to compare different concentrates, PK can support tailoring of hemophilia treatment by individual profiling, which is greatly simplified by adopting a PopPK/Bayesian method and limited sampling protocol.

Introduction: Patients with Von Willebrand disease (VWD) are regularly treated with VWF-containing concentrates in case of acute bleeding, trauma and dental or surgical procedures., Aim: In this multicentre retrospective study, current perioperative management with a von Willebrand factor (VWF)/Factor VIII (FVIII) concentrate (Haemate ® P) in patients with VWD was evaluated., Patients/methods: Patients with VWD undergoing minor or major surgery between 2000 and 2015, requiring treatment with a VWF/FVIII concentrate (Haemate ® P), were included. Achieved VWF activity (VWF:Act) and FVIII during FVIII-based treatment regimens were compared to predefined target levels in national guidelines., Results: In total, 103 patients with VWD (148 surgeries) were included: 54 type 1 (73 surgeries), 43 type 2 (67 surgeries) and 6 type 3 (8 surgeries). Overall, treatment resulted in high VWF:Act and FVIII levels, defined as ≥0.20 IU/mL above predefined levels. In patients with type 1 VWD, respectively, 65% and 91% of trough VWF:Act and FVIII levels were higher than target levels. In patients with type 2 and type 3 VWD, respectively, 53% and 57% of trough VWF:Act and 72% and 73% of trough FVIII levels were higher than target level. Furthermore, FVIII accumulation over time was observed, while VWF:Act showed a declining trend, leading to significantly higher levels of FVIII than VWF:Act., Conclusion: High VWF:Act and accumulation of FVIII were observed after perioperative FVIII-based replacement therapy in patients with VWD, both underlining the necessity of personalization of dosing regimens to optimize perioperative treatment., (© 2018 The Authors. Haemophilia Published by John Wiley & Sons Ltd.)

Background: Patients with severe and moderate haemophilia A are treated prophylactically with factor VIII (FVIII) concentrate. Individualization of prophylaxis can be achieved by pharmacokinetic (PK)-guided dosing., Aim: In this study, the performance of three PK tools (myPKFiT, Web-Accessible Population Pharmacokinetic Service-Hemophilia [WAPPS] and NONMEM) is compared., Methods: In 39 patients, with severe or moderate haemophilia A, blood samples were collected 4, 24 and 48 hours after administration of 50 IU kg -1 of recombinant FVIII (Advate [ n  = 30] or Kogenate [ n  = 9]). FVIII dose, FVIII activity and patient characteristics were entered into the three PK tools. Obtained PK parameters and dosing advises were compared., Results: myPKFiT provided PK parameters for 24 of 30 patients receiving Advate, whereas WAPPS and NONMEM provided estimates for all patients. Half-life was different among the three methods: medians were 12.6 hours ( n  = 24), 11.2 hours ( n  = 30) and 13.0 hours ( n  = 30) for myPKFiT, WAPPS and NONMEM ( p  < 0.001), respectively. To maintain a FVIII trough level of 0.01 IU mL -1 after 48 hours, doses for myPKFiT and NONMEM were 15.1 and 11.0 IU kg -1 ( p  < 0.01, n  = 11) and for WAPPS and NONMEM were 9.0 and 8.0 IU kg -1 ( p  < 0.01, n  = 23), respectively. In nine patients receiving Kogenate, WAPPS and NONMEM produced different PK-parameter estimates; half-life was 15.0 and 12.3 hours and time to 0.05 IU mL -1 was 69.2 and 60.8 hours, respectively ( p  < 0.01, n  = 9). However, recommended doses to obtain these levels were not different., Conclusion: The three evaluated PK tools produced different PK parameters and doses for recombinant FVIII. Haematologists should be aware that recommended doses may be influenced by the choice of PK tool., Competing Interests: All authors have completed the competing interest form and have no financial or personal relationships that could inappropriately influence the study. M.H.C. has received unrestricted research/educational funding for various projects and other ‘OPTI-CLOT’ projects as well as travel funding from the following companies: Pfizer, Baxter, Bayer Schering Pharma, Novo Nordisk Novartis and CSL Behring. F.W.G.L. has received unrestricted research grants from CSL Behring and Shire and has consulted for UniQure, Shire, Novo Nordisk and has received travel support from Roche. None of these activities were related to the current study. Other authors declare no competing financial interests., (Schattauer GmbH Stuttgart.)

Introduction: Due to interindividual variation in desmopressin response, non-severe haemophilia A patients require desmopressin testing prior to therapeutic treatment. However, adequate response or frequency of blood sampling is not standardised in international guidelines. Consequently, various definitions and blood sampling protocols are currently applied. Interestingly, sustainability of desmopressin response is not incorporated into these definitions., Aim: To study desmopressin response rates in a cohort of non-severe haemophilia A patients using currently accepted desmopressin response definitions. This, in order to formulate a standardised, uniform response which includes information on sustainability and to design a standardised blood sampling protocol., Methods: Currently used desmopressin responses in non-severe haemophilia A patients were derived from a literature search. Actual desmopressin response rates were individualised in 105 non-severe HA patients from the Erasmus University Medical Centre and classified according to current varying definitions., Results: Five response definitions were evaluated, three of which included only factor VIII (FVIII):C cut-off levels and two also incorporated FVIII:C-fold increase over baseline., Fviii: C-fold increase showed no association with desmopressin response sustainability., Fviii: C 1 hour after infusion (<0.30, ≥0.30-0.49, ≥0.50-0.79 and ≥0.80 IU/mL) was, however, indicative of desmopressin response after 6 hours., Conclusion: We suggest standardised desmopressin response based on clinically relevant FVIII:C levels, e.g. 0.30 and 0.50 IU/mL. In addition, patients with <0.30 IU/mL FVIII:C after 1 hour (non-responder) or ≥0.80 IU/mL (sustained responder) do not require subsequent blood sampling. However, patients with ≥0.30-0.79 IU/mL FVIII:C after 1 hour should undergo blood sampling after 6 hours to additionally determine response sustainability., (© 2017 John Wiley & Sons Ltd.)

Essentials Individual pharmacokinetic (PK) parameters can be obtained by limited sampling strategies (LSSs). Following 100 IU kg -1 rFIX, LSSs with 1 to 3 samples were evaluated in 5000 simulated subjects. For all LSSs, estimated individual PK parameters showed acceptable bias and precision. One sample between 10 min-3 h and two between 48 h-56 h showed best predictive performance., Summary: Background Patients with severe hemophilia B regularly administer prophylactic intravenous doses of clotting factor IX concentrate to maintain a trough level of at least 0.01 IU mL -1 in order to prevent joint bleeds. Assessment of individual pharmacokinetic (PK) parameters allows individualization of the recombinant factor IX (rFIX) dose. Aim To evaluate the predictive performance of limited sampling strategies (LSSs) with one to three samples to estimate individual PK parameters of rFIX. Methods Monte Carlo simulations were performed to obtain 5000 concentration-time profiles by the use of population PK parameters for rFIX from literature. Eleven LSSs were developed with one, two or three samples taken within an 80-h interval following administration of 100 IU kg -1 rFIX. Clearance (CL), half-life (t 1/2 ), time to 1% and steady-state distribution volume (V ss ) were estimated for each simulated individual by the use of Bayesian analysis. Results For each LSS, average bias was small for CL (range - 1.5% to 1.4%), t 1/2 (range - 4.5% to - 0.7%), time to 1% (range - 2.9% to 0%), and V ss (range - 3.7% to 0.3%). Imprecision for these parameters ranged from 6.4% to 11.9%, from 10.3% to 15.6%, from 7.3% to 10.9%, and from 9% to 20.1%, respectively. The best predictive performance was achieved with one sample taken between 10 min and 3 h and two samples taken between 48 h and 56 h after administration of rFIX. Conclusions This study demonstrates that limited sampling strategies, used for individualized dosing of rFIX in hemophilia B patients, can be developed and evaluated by in silico simulation., (© 2017 International Society on Thrombosis and Haemostasis.)

Background: Transmural support by a haemophilia nurse may improve treatment and may empower parents and patients., Aim: To measure the effect of structured home visits by a haemophilia nurse in (parents of) patient on aspects of prophylactic home treatment., Methods: A multicentre intervention study in two paediatric haemophilia treatment centres was performed. Primary outcome measures were: adherence to prescribed treatment, health-related quality of life and behavioural scores. Secondary outcome measures were: total clotting factor consumption, self-efficacy and number of joint bleeds., Results: Over a period of 22 months (median, IQR 21-23), four to seven home visits in 46 patients (mean age 9.4 ± 4.2 years) were made. No difference in adherence to prescribed treatment was seen after the home visits when compared to baseline measurements. Both the Child Health Questionnaire (CHQ) scales on 'Role functioning - Emotional/Behavioural' (P = 0.02, d = 0.53) and 'Parental Time Impact' (P = 0.04, d = 0.33) were reduced after intervention. The disease-specific Haemo-QoL questionnaire showed improvement in domains: 'Family' (P = 0.04, d = -0.14), 'Friends' (P = 0.03, d = -0.29) and 'Perceived support' (P = 0.03, d = -0.37). Significant improvement was observed with regard to domain 'Communication' of the VERITAS-Pro scale (P = 0.03, d = -0.28)., Conclusions: After a period of transmural care by a haemophilia nurse, significant but small positive effects were demonstrated with regard to communication and increase of perceived support between parents and haemophilia treatment centre. No improvement was observed in other outcome measures., (© 2016 John Wiley & Sons Ltd.)

The role of pharmacokinetic-guided dosing of factor concentrates in hemophilia is currently a subject of debate and focuses on long-term prophylactic treatment. Few data are available on its impact in the perioperative period. In this study, a population pharmacokinetic model for currently registered factor VIII concentrates was developed for severe and moderate adult and pediatric hemophilia A patients (FVIII levels <0.05 IUmL -1 ) undergoing elective, minor or major surgery. Retrospective data were collected on FVIII treatment, including timing and dosing, time point of FVIII sampling and all FVIII plasma concentrations achieved (trough, peak and steady state), brand of concentrate, as well as patients' and surgical characteristics. Population pharmacokinetic modeling was performed using non-linear mixed-effects modeling. Population pharmacokinetic parameters were estimated in 75 adults undergoing 140 surgeries (median age: 48 years; median weight: 80 kg) and 44 children undergoing 58 surgeries (median age: 4.3 years; median weight: 18.5 kg). Pharmacokinetic profiles were best described by a two-compartment model. Typical values for clearance, intercompartment clearance, central and peripheral volume were 0.15 L/h/68 kg, 0.16 L/h/68 kg, 2.81 L/68 kg and 1.90 L/68 kg. Interpatient variability in clearance and central volume was 37% and 27%. Clearance decreased with increasing age (P<0.01) and increased in cases with blood group O (26%; P<0.01). In addition, a minor decrease in clearance was observed when a major surgical procedure was performed (7%; P<0.01). The developed population model describes the perioperative pharmacokinetics of various FVIII concentrates, allowing individualization of perioperative FVIII therapy for severe and moderate hemophilia A patients by Bayesian adaptive dosing., (Copyright© Ferrata Storti Foundation.)

Background and Purpose: Children with sickle cell disease have low hematocrit and elevated CBF, the latter of which can be assessed with arterial spin-labeling MR imaging. Quantitative CBF values are obtained by using an estimation of the longitudinal relaxation time of blood (T1blood). Because T1blood depends on hematocrit in healthy individuals, we investigated the importance of measuring T1blood in vivo with MR imaging versus calculating it from hematocrit or assuming an adult fixed value recommended by the literature, hypothesizing that measured T1blood would be the most suited for CBF quantification in children with sickle cell disease., Materials and Methods: Four approaches for T1blood estimation were investigated in 39 patients with sickle cell disease and subsequently used in the CBF quantification from arterial spin-labeling MR imaging. First, we used 1650 ms as recommended by the literature (T1blood-fixed); second, T1blood calculated from hematocrit measured in patients (T1blood-hematocrit); third, T1blood measured in vivo with a Look-Locker MR imaging sequence (T1blood-measured); and finally, a mean value from T1blood measured in this study in children with sickle cell disease (T1blood-sickle cell disease). Quantitative flow measurements acquired with phase-contrast MR imaging served as reference values for CBF., Results: T1blood-measured (1818 ± 107 ms) was higher than the literature recommended value of 1650 ms, was significantly lower than T1blood-hematocrit (2058 ± 123 ms, P < .001), and, most interesting, did not correlate with hematocrit measurements. Use of either T1blood-measured or T1blood-sickle cell disease provided the best agreement on CBF between arterial-spin labeling and phase-contrast MR imaging reference values., Conclusions: This work advocates the use of patient-specific measured T1blood or a standardized value (1818 ms) in the quantification of CBF from arterial spin-labeling in children with SCD., (© 2016 by American Journal of Neuroradiology.)

Objective: Adolescents with a chronic disorder, such as haemophilia, need to attain responsibility for their disease. The aim was to gain insight into how adolescents achieve self-management of prophylactic treatment., Methods: In three Dutch Haemophilia Treatment Centres, adolescents (10-25 years) received structured questions on treatment responsibility and self-management (pre-specified definitions) during routine nursing consultation., Results: In total, 155 interviews were performed in 100 patients (median age 14.4 years). Self-infusion was initiated at a median age of 12.3 years (IQR 11.5-13.0) and self-management was achieved 9.6 years later, at a median age of 22.6 years. This process included three phases coinciding with known stages of adolescence. In early adolescence, patients acquired the technique of self-infusion (12.3 years) leading to independent self-infusion in middle adolescence (17.2 years). In late adolescence, patients demonstrated an increase in more complex skills, such as bleeding management and communication with the haemophilia physician (19.9-22.6 years)., Conclusion: Although, the first steps in self-management with regard to self-infusion are taken in early adolescence, complete self-management was achieved in late adolescence after almost 10 years., Practice Implications: Insight in this transitional process helps to provide individualized support and emphasizes the need for continued education with regard to self-management skills., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Unlabelled: ESSENTIALS: Targeting of factor VIII values is a challenge during perioperative replacement therapy in hemophilia. This study aims to identify the extent and predictors of factor VIII underdosing and overdosing. Blood group O predicts underdosing and is associated with perioperative bleeding. To increase quality of care and cost-effectiveness of treatment, refining of dosing is obligatory., Background: Perioperative administration of factor VIII (FVIII) concentrate in hemophilia A may result in both underdosing and overdosing, leading to respectively a risk of bleeding complications and unnecessary costs., Objectives: This retrospective observational study aims to identify the extent and predictors of underdosing and overdosing in perioperative hemophilia A patients (FVIII levels < 0.05 IU mL(-1))., Patients and Methods: One hundred nineteen patients undergoing 198 elective, minor, or major surgical procedures were included (median age 40 years, median body weight 75 kg). Perioperative management was evaluated by quantification of perioperative infusion of FVIII concentrate and achieved FVIII levels. Predictors of underdosing and (excessive) overdosing were analyzed by logistic regression analysis. Excessive overdosing was defined as upper target level plus ≥ 0.20 IU mL(-1)., Results: Depending on postoperative day, 7-45% of achieved FVIII levels were under and 33-75% were above predefined target ranges as stated by national guidelines. A potential reduction of FVIII consumption of 44% would have been attained if FVIII levels had been maintained within target ranges. Blood group O and major surgery were predictive of underdosing (odds ratio [OR] 6.3, 95% confidence interval [CI] 2.7-14.9; OR 3.3, 95% CI 1.4-7.9). Blood group O patients had more bleeding complications in comparison to patients with blood group non-O (OR 2.02, 95% CI 1.00-4.09). Patients with blood group non-O were at higher risk of overdosing (OR 1.5, 95% CI 1.1-1.9). Additionally, patients treated with bolus infusions were at higher risk of excessive overdosing (OR 1.8, 95% CI 1.3-2.4)., Conclusion: Quality of care and cost-effectiveness can be improved by refining of dosing strategies based on individual patient characteristics such as blood group and mode of infusion., (© 2015 International Society on Thrombosis and Haemostasis.)

Background: Joint bleeds are reported by 23% of von Willebrand disease (VWD) patients and associated with orthopaedic surgery. Limited data are available on joint surgery in VWD., Aim: To assess the prevalence, indications, management and complications of joint surgery in VWD patients., Methods: 804 VWD patients with historically lowest von Willebrand factor (VWF) activity ≤30 U dL -1 completed a questionnaire on joint bleeds, joint damage and orthopaedic surgery. We retrieved additional medical file data of patients who underwent surgery on large joints (shoulder, elbow, hip, knee or ankle)., Results: 116 out of 804 patients (14%) reported large joint surgery. Compared to VWD patients without previous orthopaedic surgery, these 116 patients reported more frequently a history of joint bleeds and joint damage (41% vs. 20%, P < 0.001 and 61% vs. 20%, P < 0.001). Medical file data on 126 large joint surgeries in 79 VWD patients revealed that this surgery was associated with joint damage due to prior joint bleeds in 24% of the procedures. Preoperative clotting factor correction (CFC) to prevent bleeding was administered in most cases (81%). Documentation on postoperative bleeding was found in 23 surgeries (18%)., Conclusions: Large joint surgery is reported by 14% of VWD patients, related to joint bleeds in 24% and seems associated with bleeding complications frequently despite perioperative CFC., (© 2015 John Wiley & Sons Ltd.)

Introduction: Desmopressin is frequently used in patients with bleeding disorders because of its prohaemostatic effects. In recent years desmopressin use increased due to reported high incidence of inhibitors in mild haemophilia after clotting factor infusion and the rising costs of clotting factor concentrates. The safety and frequency of side effects have hardly been assessed in well-designed studies., Aim: We therefore prospectively evaluated side effects of desmopressin in a large unselected cohort of bleeding disorder patients, who received a desmopressin test dose., Methods: Blood was drawn prior to, one, three, six and 24 h after desmopressin. Primary outcome was change in serum sodium, haematocrit, serum- and urine osmolality, body weight and vital signs. Self-reported side effects were evaluated as secondary outcome., Results: In total, 108 patients were included, median age 30 years, the majority of whom had von Willebrand disease type 1 (76%). A significant change in water balance parameters was observed. Four patients (4%) had hyponatraemia (≤135 mmol L(-1) ) after 24 h but no severe hyponatraemia occurred (≤125 mmol L(-1) ). After infusion, 41 (38%) patients were hypotensive (≤90 mmHg SBP and/or ≤60 mmHg DBP) and 10 (9%) presented with tachycardia (>100 min(-1) ). However, none of these effects sustained at 24 h. Infusion was discontinued in one patient because of tachycardia, nausea and malaise. Self-reported side effects included: headache, fatigue, flush and dizziness., Conclusion: Observed side effects correspond with the known antidiuretic and vasomotor effects of desmopressin. Changes in parameters were temporary and not clinically relevant. In conclusion, our study supports desmopressin use as a safe treatment option in patients with various bleeding disorders., (© 2015 John Wiley & Sons Ltd.)

Introduction: Patients', parents' and providers' preferences with regard to medical innovations may have a major impact on their implementation., Aim: To evaluate barriers and facilitators for individualized pharmacokinetic (PK)-guided dosing of prophylaxis in haemophilia patients, parents of young patients, and treating professionals by discrete choice experiment (DCE) questionnaire., Patients/methods: The study population consisted of patients with haemophilia currently or previously on prophylactic treatment with factor concentrate (n = 114), parents of patients aged 12-18 years (n = 19) and haemophilia professionals (n = 91). DCE data analysis was performed, taking preference heterogeneity into account., Results: Overall, patients and parents, and especially professionals were inclined to opt for PK-guided dosing of prophylaxis. In addition, if bleeding was consequently reduced, more frequent infusions were acceptable. However, daily dosing remained an important barrier for all involved. 'Reduction of costs for society' was a facilitator for implementation in all groups., Conclusions: To achieve implementation of individualized PK-guided dosing of prophylaxis in haemophilia, reduction of bleeding risk and reduction of costs for society should be actively discussed as they are motivating for implementation; daily dosing is still reported to be a barrier for all groups. The knowledge of these preferences will enlarge support for this innovation, and aid in the drafting of implementable guidelines and information brochures for patients, parents and professionals., (© 2015 John Wiley & Sons Ltd.)

Background: von Willebrand factor (VWF) levels in healthy individuals are influenced by variations in genetic loci other than the VWF gene, whose contribution to VWF levels in patients with von Willebrand disease (VWD) is largely unknown., Objectives: To investigate the association between single-nucleotide polymorphisms (SNPs), VWF levels, and bleeding phenotype., Patients/methods: In 364 type 1 VWD and 240 type 2 VWD patients from the nationwide cross-sectional 'Willebrand in The Netherlands' (WiN) study, we studied the association between eight SNPs in STXBP5, SCARA5, ABO, VWF, STAB2, STX2, TC2N, and CLEC4M, and VWF antigen (VWF:Ag), VWF activity (VWF:Act), and bleeding phenotype as assessed with the Tosetto bleeding score., Results: In type 1 patients, STXBP5 was associated with a lower VWF:Ag level (adjusted difference of -3.0 IU dL(-1) per allele; 95% confidence interval [CI] -6.0 to 0.1) and CLEC4M with both a lower VWF:Ag level (-4.3 IU dL(-1) per allele; 95% CI -7.9 to -0.6) and lower VWF:Act (-5.7 IU dL(-1) per allele; 95% CI -10.9 to -0.5). In type 2 patients, none of the SNPs was associated with VWF levels. None of the genetic variants was associated with bleeding score., Conclusions: Genetic variations in STXBP5 and CLEC4M are associated with VWF level variation in type 1 VWD, but not in type 2 VWD. This study increases our understanding of the pathophysiology of VWD, and provides a further indication of the involvement of STXBP5 and CLEC4M in determining VWF levels in VWD., (© 2015 International Society on Thrombosis and Haemostasis.)

Background: Joint bleeds (JB) are reported in a minority of patients with von Willebrand disease (VWD) but may lead to structural joint damage. Prevalence, severity and impact of JB in VWD are largely unknown., Objectives: The aim of this study was to assess JB prevalence, onset, treatment and impact on health-related quality of life (HR-QoL) and joint integrity in moderate and severe VWD., Methods: In the Willebrand in the Netherlands study 804 moderate and severe VWD patients [von Willebrand factor (VWF) activity ≤30U dL(-1)] completed a questionnaire on occurrence, sites and consequences of JB. To analyse JB number, onset, treatment and impact on joint integrity we additionally performed a patient-control study on medical file data comparing patients with JB to age, gender, factor VIII (FVIII)- and VWF activity matched VWD patients without JB., Results: Of all VWD patients 23% (184/804) self-reported JB. These 184 patients reported joint damage more often (54% vs. 18%, P < 0.001) and had lower HR-QoL (SF36, P < 0.05) compared to VWD patients not reporting JB. Of 55 patients with available JB data, 65% had the first JB before age 16. These 55 patients used more clotting factor concentrate (CFC; median dose 43 vs. 0 IE FVIII kg(-1) year(-1) , P < 0.001), more often had X-ray joint damage (44% vs. 11%, P = 0.001] and chronic joint pain (44% vs. 18%, P = 0.008) compared to 55 control VWD patients without JB., Conclusion: In conclusion, joint bleeds are reported by 23% of moderate and severe VWD patients, mostly start in childhood, are associated with more CFC use, joint pain, lower HR-QoL and significantly more radiological and self-reported joint damage., (© 2015 John Wiley & Sons Ltd.)

Treatment adherence in haemophilia is strongly associated with quality of life and the cost-benefit of treatment. Therefore, it is important to quantify and monitor it. This study aimed to validate a translation of the VERITAS-Pro cross-culturally and analyse treatment adherence in a Dutch population of paediatric haemophilia patients. Children aged 1-18 years with haemophilia were included from three Haemophilia Treatment Centres, on prophylactic clotting factor replacement therapy for more than 1 year. Parents and adolescents were analysed separately. The adherence scale for prophylactic therapy (VERITAS-Pro) was translated according to international guidelines. This instrument contains a total of six subscales ('Time', 'Dose', 'Plan', 'Remember', 'Skip' and 'Communicate') each with four items. Lower scores reflect higher adherence. Overall response rate was 85%, leading to a study population of 60 children. Mean age was 10 years (SD 4.1). Internal consistency reliability: Mean Cronbach's alphas were adequate (>0.70) for total score and the subscales 'Skip' and 'Communicate'. Item-own subscale correlations were stronger than most item-other subscale correlations. Convergent validity: Total scores were higher for non-adherent participants compared with adherent participants according to patient infusion logs (n = 48; P < 0.05). Test-retest correlations: Significant for all scales except 'Dose' (n = 58; P < 0.01). This study demonstrates applicability of VERITAS-Pro outside the United States, as total score and most subscales effectively quantified treatment adherence in a Dutch paediatric population on prophylactic therapy. Non-adherent respondents' total scores were significantly higher, demonstrating the ability of VERITAS-Pro to identify non-adherent individuals., (© 2014 John Wiley & Sons Ltd.)

Higher self-efficacy in chronic disease patients is associated with higher development of self-management skills and increased quality-of-life. Quantification and monitoring of self-efficacy is therefore of importance. Self-efficacy in haemophilia patients has received little attention due to lack of standardized scales. To validate the novel Haemophilia-specific Self-Efficacy Scale (HSES) in haemophilia patients on prophylactic home treatment, haemophilia patients aged 1-18 years on prophylactic treatment ≥1 year were included from three Dutch Haemophilia Treatment Centres. The HSES consists of 12 items, relating to perceptions of the ability to function on a day-to-day basis with regard to patient's disease. Retest was performed in a subsample. Validity was proven by the General Self-Efficacy Scale and by the health-related quality-of-life assessment tool Haemo-QoL. Data were analysed from 53 children (response 75%), with a mean age of 9.8 years (SD 4.0). Mean total scale score of HSES was 55.5 (SD 4.7; range 38-60), with a ceiling effect of 17%. The HSES showed adequate internal consistency (Cronbach's alpha 0.72) and good test-retest reliability (Intra-Class-Correlation coefficient 0.75; P < 0.01; n = 37). The convergent validity was adequate as haemophilia-specific self-efficacy correlated significantly with general self-efficacy (r = 0.38; P < 0.01). High HSES scores correlated significantly with quality-of-life as measured by the Haemo-QoL (r = -0.42; P ≤ 0.01). The novel HSES is a reliable and valid tool to assess self-efficacy in paediatric haemophilia patients on prophylactic home treatment. High self-efficacy correlated with higher quality-of-life, further underlining the importance to standardly assess, monitor and improve self-efficacy., (© 2014 John Wiley & Sons Ltd.)

Background: Because the number of elderly von Willebrand disease (VWD) patients is increasing, the pathophysiology of aging in VWD has become increasingly relevant., Objectives: To assess age-related changes in von Willebrand factor (VWF) and factor VIII (FVIII) levels and to compare age-related differences in bleeding phenotype between elderly VWD patients and those < 65 years. We also studied co-morbidity in elderly patients., Patients/methods: We included VWD patients with VWF levels ≤ 30 U dL(-1) in the nationwide cross-sectional 'Willebrand in the Netherlands' (WiN-) study. Patients reported bleeding episodes and treatment of VWD in the year preceding inclusion and during life. This was compared between VWD patients older (n = 71) and younger (16-64 years, n = 593) than 65 years. In elderly patients, age-related changes in VWF and FVIII levels were studied longitudinally by including all historically measured levels. All medical records were examined for co-morbidity., Results: In elderly type 1 patients, a decade age increase was associated with a 3.5 U dL(-1) (95% CI, -0.6 to 7.6) VWF:Ag increase and 7.1 U dL(-1) (95% CI, 0.7 to 13.4) FVIII:C increase. This increase was not observed in elderly type 2 patients. Elderly type 2 patients reported significantly more bleeding symptoms in the year preceding inclusion than younger patients (16/27, 59% vs. 87/221, 39%; P = 0.048), which was not observed in type 1 VWD., Conclusions: von Willebrand factor parameters and bleeding phenotype evolve with increasing age in VWD. VWF and FVIII levels increase with age in type 1 patients with no mitigation in bleeding phenotype. In type 2 patients VWF parameters do not increase with age and in these patients aging is accompanied by increased bleeding., (© 2014 International Society on Thrombosis and Haemostasis.)

Background: The working alliance between therapist and patient has been investigated frequently, but much less is known about the working alliance in specific patient groups in specific settings., Aim: To obtain insight into the characteristics of the working alliance in intensive inpatient psychotherapy involving patients with severe personality disorders, and to pay special attention to patient characteristics such as diagnosis and attachment., Method: At the end of the first phase of treatment we collected, on the basis of questionnaires, information about the working alliance and attachment of 60 patients with a severe personality disorders who had received inpatient psychotherapy., Results: Working alliances with therapist and team were found to be weaker than in outpatient populations; working alliances with the therapist proved to be stronger than working alliances with the treatment team. Cluster C patients developed a better working alliance with the treatment team than did cluster B patients, particularly in the domain of treatment goals. Patients in this study turned out to be attached more anxiously and 'avoidantly' than patients in general outpatient populations; no correlation was found between patients' attachment and the strength of the working alliance. However, when a distinction was made between patients with extreme scores and patients with average scores, results showed that the more anxiously patients felt attached, the higher were their scores for their working alliance with the treatment team., Conclusion: It is more difficult to establish a working alliance with patients who have a severe personality disorder than with patients suffering from a less severe personality disorder. Patients with a severe personality disorder seemed to show a higher degree of anxious attachment and to have a more critical attitude to the working alliance.

Background: High von Willebrand factor (VWF) levels are an established risk factor for arterial thrombosis, including coronary heart disease and ischemic stroke. It has been hypothesized that von Willebrand disease (VWD) patients are protected against arterial thrombosis; however, this has never been confirmed in clinical studies., Objectives: To investigate the prevalence of arterial thrombosis in VWD patients relative to the general population., Patients/methods: We included 635 adult patients with VWF levels ≤ 30 U dL(-1) , aged 16-85 years, from the nationwide cross-sectional 'Willebrand in the Netherlands' (WiN) study and compared the prevalence of arterial thrombosis with two reference populations from the general Dutch population adjusted for age and sex as standardized morbidity ratios (SMRs)., Results: Twenty-nine arterial thrombotic events occurred in 21 patients (3.3%). Five patients suffered an acute myocardial infarction and three an ischemic stroke. Unstable angina pectoris was recorded 12 times, transient ischemic attack nine. The prevalence of all arterial thrombotic events combined (acute myocardial infarction, ischemic stroke and coronary heart disease) was 39% and 63% lower than in the two reference populations. The prevalence of cardiovascular disease in VWD was lower than in the general population, SMR 0.60 (95% CI, 0.32-0.98) for coronary heart disease and SMR 0.40 (95% CI, 0.13-0.83) for acute myocardial infarction. For ischemic stroke the prevalence was 35-67% lower compared with two reference populations, SMR 0.65 (95% CI, 0.12-1.59) and 0.33 (95% CI, 0.06-0.80), respectively., Conclusions: This is the first study showing that VWD patients have a reduced prevalence of arterial thrombosis and provides important insights into the role of VWF in the pathogenesis of arterial thrombosis., (© 2013 International Society on Thrombosis and Haemostasis.)

Background: Use of age-adjusted reference values is crucial for correct diagnosis and management of thrombotic and hemorrhagic disease in children. They vary with utilized reagents and analyzers., Objectives: We established reference values with the Sysmex CA-1500 System and in parallel with the Behring BCS System using reagents from Siemens Healthcare Diagnostics Products GmbH., Methods: After informed consent, blood samples were obtained from 218 healthy children and 52 healthy adults, grouped as 1-6 months (n = 29), 7-12 months (n = 25), 1-5 years (n = 57), 6-10 years (n = 57), 11-18 years (n = 50) and > 19 years (n = 52)., Results: Most coagulation parameters demonstrate good comparability between analyzers with the exception of PT and APTT. Single coagulation factors fibrinogen, factor (F) II, FIX, FXI and XII were significantly decreased in the youngest children; the strongest age dependency was found for coagulation inhibitors Protein C and S, both significantly decreased in infancy and young childhood. We confirmed that high levels of von Willebrand factor are found in the youngest children without increased levels of FVIII followed by decreased von Willebrand levels in the subsequent age group. In children with blood group O a less distinct increase in time was found, compared with individuals with one of the other blood groups., Conclusions: The correlation between the CA-1500 and the BCS system was remarkable. Differences were most pronounced between children < 12 months and older children and adults, confirming the phenomenon of developmental hemostasis. The rationale for age-related changes in the hemostatic system remains unraveled. Our results underline the need for age-specific reference ranges., (© 2012 International Society on Thrombosis and Haemostasis.)

The Group Medical Appointment (GMA) is a novel consultation form in which patients undergo individual consultations in each other's presence. To compare participants' experiences with GMA and Individual Medical Appointments (IMA), the usual standard of care, our team recently implemented the GMA for children aged 0-18 years with haemophilia or von Willebrand's disease. Participants' experiences with GMA were measured using a standardized QUOTE-questionnaire. Of 100 addressed families, 53 participated in GMA. Of these 53 families, 38 parents (72%) and 14 adolescents (82%) filled in the questionnaire about the GMA. Patients not on prophylaxis were defined as less experienced and patients on prophylaxis, as experienced. Although parents were satisfied with both GMA and IMA (median score 8.0 vs. 9.0 of 10), a significant difference was demonstrated between less experienced and experienced parents. After GMA, less experienced parents were significantly more satisfied (median score 8.0 vs. 5.0; P-value 0.006), felt more social support (82% vs. 30%; P-value 0.005) and reported additional learning effects with regard to disease and treatment (64% vs. 0%; P-value <0.001) than experienced parents. None of the less experienced parents reported privacy problems during GMA compared with 40% of experienced parents. In adolescents an identical trend was reported. Sixty-six per cent of parents would join a GMA in the future and 87% would recommend a GMA to others. The GMA is a valuable addition in haemophilia and von Willebrand care, especially for less experienced patients. It leads to improved satisfaction, social support and improved information., (© 2012 Blackwell Publishing Ltd.)

Objectives: To evaluate the relationship between FAST peak percentage by adapted Bio-Rad Vnbs analysis using the valley-to-valley integration and genotypes with the aim to improve differentiation between severe α-thalassaemia forms (HbH disease) and the milder disease types., Method: DNA analysis for α-thalassaemia was performed on 91 dried blood spot samples presenting normal and elevated FAST peak levels, selected during three years of Dutch national newborn screening., Results: Significant differences were found between samples with and without α-thalassaemia mutations, regardless of the genetic profiles. No significant difference was demonstrated between HPLC in -α/αα and -α/-α, between -α/-α and - -/αα and between - -/αα and - -/-α genotypes., Conclusion: This study confirms that the percentage HbBart's, as depicted by the FAST peak, is only a relative indication for the number of α genes affected in α-thalassaemia. Based on the data obtained using the modified Bio-Rad Vnbs software, we adopted a cut-off value of 22.5% to discriminate between possible severe α-thalassaemia or HbH disease and other α-thalassaemia phenotypes. Retrospectively, if this cut-off value was utilized during this initial three-year period of neonatal screening, the positive predictive value would have been 0.030 instead of 0.014.

The detection rate of perinatal stroke is rising due to improved neuroradiological imaging techniques, increased survival of neonates with severe underlying diseases and an increased awareness of the diagnosis by pediatricians. Its pathogenesis is multifactorial and includes a large variety of maternal and neonatal risk factors as well as prothrombotic coagulation factors. Although the relative risk of prothrombotic coagulation factors is still unknown, testing is recommended to design large studies in the near future. This article is an overview of studies of prothrombotic risk factors in both neonatal arterial ischemic stroke and cerebral sinovenous thrombosis. Although prothrombotic coagulation factors are present in more than half of the cases, we conclude that they most likely play a minor role in the pathogenesis of perinatal stroke. Current therapeutic guidelines focusing on thrombosis are based on expert opinion and recommend low molecular weight or unfractionated heparin for cardioembolic arterial ischemic stroke, antiplatelet or anticoagulant therapy for recurrent arterial ischemic stroke, and low molecular weight heparin or unfractionated heparin for sinovenous thrombosis without hemorrhage and/or when extension of the thrombotic process occurs.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease characterised by café-au-lait spots, freckling in the axillary or inguinal region, dermal and plexiform neurofibromas and Lisch nodules. Complications are severe in one third of patients, and the clinical variability is pronounced, even within families. The NF1 gene has been localised to chromosome 17q11.2 and encodes the protein neurofibromin. The gene is proposed to be a tumour suppressor gene. Inactivation of neurofibromin leads to a disruption in cell growth regulation. Mutation analysis is possible but laborious, and therefore NF1 is generally a clinical diagnosis based on diagnostic criteria.

Objective: To establish the frequency of minor disease features in children with neurofibromatosis type 1 (NF1) and to evaluate the value of minor disease features in children < or = 6 years with a suspected diagnosis of NF1, considering that the disease is virtually 100% penetrant at 6 years of age., Design: During this 10 year, prospective, multidisciplinary, follow up study, 209 children suspected of having NF1 were examined; 150 were diagnosed with NF1 and 59 were not. The present analysis included children in whom NF1 was considered to be present at 6 years of age (n=85) and children without NF1 at 6 years of age (n=42)., Results: The minor disease features macrocephaly (52.9%), short stature (24.7%), hypertelorism (63.5%), and thorax abnormalities (37.6%) were highly prevalent in children with NF1 and significantly associated with a diagnosis of NF1 at 6 years of age. In addition, the mean number of minor disease features was significantly higher in children with NF1 at 6 years of age compared to the group without a diagnosis at 6 years of age (mean 1.8 v 0.8, p<0.001). Moreover, children with three or more minor disease features were all diagnosed with NF1 under the age of 6 years. Multivariate analysis using a logistic regression model showed that macrocephaly, short stature, hypertelorism, and thorax abnormalities were all independently associated with the presence of NF1 at 6 years of age., Conclusion: In children with insufficient diagnostic criteria aged < or = 6 years, documentation of minor disease features may be a helpful aid in predicting the diagnosis of NF1 in years to come.

Objective: To establish the prevalence and incidence of symptoms and complications in children with neurofibromatosis type 1 (NF1) and to assess possible risk factors for the development of complications., Design: A 10 year prospective multidisciplinary follow up study., Patients: One hundred and fifty children diagnosed with NF1 according to criteria set by the National Institutes of Health., Results: In 62 of 150 children (41.3%) complications were present, including 42 (28.0%) children with one complication, 18 (12.0%) with two complications, and two (1.3%) with three complications (mean (SD) duration of follow up 4.9 (3.8) years). Ninety five of the 150 children presented without complications (follow up, 340.8 person-years). The incidence of complications was 2.4/100 person-years in this group. An association was found between behavioural problems and the presence of complications., Conclusion: This is the largest single centre case series of NF1 affected children followed until 18 years of age. Children with NF1, including those initially presenting without complications, should have regular clinical examinations.

The simultaneous occurrence of familial neurofibromatosis type 1 (NF1) and an overgrowth syndrome resembling Weaver syndrome was observed in two related cases (a mother and her son). NF1 was confirmed by molecular genetic analysis showing a large deletion at 17q11.2, encompassing the entire NF1 gene. The other symptoms in the two cases were similar to the features reported in Weaver syndrome. Although the combination of NF1 and an overgrowth syndrome resembling Weaver syndrome in this family may be fortuitous, we favour the hypothesis that the deletion of the entire gene has caused this combined phenotype. Possible pathogenetic mechanisms are discussed. The observation suggests a relation between NF1 with an extraordinarily large gene deletion and a Weaver(-like) syndrome. This warrants investigation for deletions in the 17q11.2 region in Weaver(-like) syndrome patients.