Abstract Number: PB1171
Meeting: ISTH 2020 Congress
Background: Patients with rare bleeding disorders (RBD) present with diverse hemorrhagic clinical symptoms and varying frequencies of bleeding episodes. The lack of a distinct correlation between factor level activity and bleeding severity, hampers diagnosis and targeted treatment.
Aims: Study aim was to determine clinical phenotype, to compare ISTH BAT with RBD BAT (Palla et al., 2016) and to validate previously determined (Peyvandi et al., 2012) threshold factor levels for bleeding severity.
Methods: The RBiN study reports results from a nation-wide cross-sectional multicenter study of patients with a known RBD including rare coagulation factor deficiencies and disorders of fibrinolysis, from six Dutch Haemophilia Treatment Centers, aged 1-99 years. After written informed consent, bleeding assessment tools (BAT) were administered and clinical data extracted from patient files.
Results: Two-hundred sixty-three patients were included, of whom 197 attended a planned study visit. Most patients suffered from provoked bleeding: bleeding after dental procedures (66%), surgery (76.4%), menorrhagia (80.2%) and postpartum hemorrhage (51.2%).The median ISTH BAT score was 10. The sensitivity of the RBD BAT was better compared to the ISTH BAT (85% versus 81%, p< 0.05), especially for women and children. Correlations between baseline factor levels and ISTH BAT scores were strong for factor (F) II deficiency (r=-0,792) and FX deficiency (r=-0,838) and moderate for deficiencies of fibrinogen (r=-0,683), FV (r=-0,623), FVII (r=-0,516),FXIII (r=-0,516) and α2-antiplasmin (r=-0,594). There was no correlation for FXI deficiency. Forty-eight percent of patients had more severe bleeding than predicted on the basis of baseline factor activity level. Thirty-four percent of patients were assumed to be asymptomatic but experienced grade II or grade III bleeding.
Conclusions: The RBD score may be a better diagnostic tool than the ISTH BAT for RBDs. Threshold factor levels for RBD patients to remain free from bleeding are often inaccurate and should be used with caution.
To cite this abstract in AMA style:Saes JL, Verhagen MJA, Meijer K, Cnossen MH, Schutgens REG, Peters M, Nieuwenhuizen L, van der Meer FJM, Kruis IC, van Heerde WL, Schols SEM, RBiN Study Group . Clinical Characteristics of Patients with Rare Bleeding Disorders: Real-Life Data from the Netherlands (RBiN Study) [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/clinical-characteristics-of-patients-with-rare-bleeding-disorders-real-life-data-from-the-netherlands-rbin-study/. Accessed January 23, 2022.
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