Comparative Effectiveness in the Diagnosis of VWD

描述（由申请人提供）：血管性血友病是一种常见的诊断出血性疾病，最近受到科学审查，因为在一些人群（月经过多）中诊断不足，同时在另一些人群中可能诊断过度（高达1-2%的人口）。在美国、加拿大、英国和欧盟进行的回顾性研究表明，当VWF水平低于30 IU/dL时，VWD的诊断通常是无可争议的。通常，当1个VWF测试低于正常范围（<50 IU/dL）时，诊断为VWD。采用30 IU/dL的严格水平，在548例VWD指数病例中，69%的VWF:Ag或VWF:RCo没有降低。本提案将前瞻性研究9个参与中心之一的血液学家的大量个体，并研究5年重复研究中局部诊断检测与中心检测的相关性。在前两年，该测试将是盲法的，并将这些结果与接下来两年的类似测试进行比较

DESCRIPTION (provided by applicant): Von Willebrand Disease is a commonly diagnosed bleeding disorder that has recently come under scientific scrutiny for being under diagnosed in some groups (menorrhagia) at the same time it may be over diagnosed in others (up to 1-2% of the population). Retrospective studies have been done in the US, Canada, UK, and EU suggesting that the diagnosis of VWD is usually incontrovertible when levels of VWF are less than 30 IU/dL. Frequently, VWD is diagnosed when 1 VWF test is below the normal range (<50 IU/dL). Using the stringent level of 30 IU/dL, 69% of 548 VWD index cases, on restudy did not have reduced VWF:Ag or VWF:RCo. This proposal will study prospectively a large cohort of individuals referred to hematologists at one of 9 participating Centers and study the correlation of local diagnostic testing to central testing on repetitive study over a 5 year period. For the fist 2 years, this testing will be blinded and these results compared to similar testing over the next 2 3 years when there will be unblinded central testing and active quality control program between these institutions. Variant (type 2) VWD is diagnosed in 15-20% of individuals with VWD. New screening tests and a new VWF-phenotyping test will be developed and evaluated in this prospective study. Several quantitative bleeding scores (QBS) have been developed that help to differentiate subjects with VWD from those without VWD, but they have not been utilized to assess actual bleeding risk. Two large cohorts, one adult and one pediatric, will be studied with several QBS and these scores compared to their risk of hemorrhage prospectively. This project proposes to improve the fidelity, cost effectiveness, and sensitivity needed to diagnose VWD