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Baseline factor VIII plasma levels and age at first bleeding in patients with severe forms of von Willebrand disease
Author(s) -
Siboni S. M.,
Biguzzi E.,
Caiani V.,
Mistretta C.,
Bucciarelli P.,
Peyvandi F.
Publication year - 2016
Publication title -
haemophilia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.213
H-Index - 92
eISSN - 1365-2516
pISSN - 1351-8216
DOI - 10.1111/hae.12900
Subject(s) - medicine , von willebrand factor , von willebrand disease , disease , baseline (sea) , pediatrics , platelet , oceanography , geology
von Willebrand disease ( VWD ) is the most common inherited bleeding disorder. The age of bleeding onset is highly variable, also in patients with similar degree of severity. Aim The primary aim of this study was to evaluate whether baseline factor VIII ( FVIII ) plasma levels correlate with age at first bleeding in patients with extremely low levels of VWF : RC o (<6 IU dL −1 ). Methods One hundred and three patients with VWF : RC o <6 IU dL −1 (6 VWD 1, 73 VWD 2 and 24 VWD 3) undergoing a medical examination between September 2010 and September 2013 were included. The relationship between baseline FVIII levels and age at first bleeding was tested in a multivariable linear regression model, adjusting for sex. Results The median age at first bleeding was lower in patients with VWD 3 than in those with severe forms of VWD 1 or VWD 2 (1 year vs. 7 and 8 years, respectively, P < 0.0001). A positive non‐linear relationship between FVIII levels and age at first bleeding was found, the latter increasing by 5 years for every 10 IU dL −1 increase of FVIII (β = 4.95 [95% CI : 2.02–7.87]) until levels of 30 IU dL −1 , after which the age increased slowly. This relationship was not found in VWD 2A and 2B. In 65 patients (63%) there was a more than 6‐month delay between bleeding onset and VWD diagnosis, with no difference over decades. Conclusions Baseline FVIII plasma levels influence the age at bleeding onset in VWD patients with extremely low levels of VWF : RC o, except in those with types 2A and 2B.