Introduction
There has been increasing recognition in recent years that female carriers of haemophilia manifest abnormal bleeding; however, data on the use of bleeding assessment tools in this population are lacking.
Aim
Our objective was to validate the ISTH‐BAT in haemophilia carriers to describe bleeding symptoms and allow for comparisons with factor levels and other patient groups.
Methods
This was a prospective, observational, cross‐sectional study performed by members of Global Emerging HEmostasis Panel (GEHEP). Unselected consecutive haemophilia carriers were recruited and a CRF and the ISTH‐BAT were completed by study personnel.
Results
A total of 168 haemophilia carriers were enrolled: 155 haemophilia A and 13 haemophilia B. The mean age was 40 years (range: 20–82). Carriers had higher mean bleeding scores (BS) compared with age‐matched controls (n = 46; 5.7 vs. 1.43; P < 0.0001) and Type 3 VWD OC (n = 32; 3.0; P = 0.009), but lower BS compared with women with Type 1 VWD (n = 83; 8.7; P < 0.0001). Fifteen carriers reported haemarthrosis, and of those six had normal FVIII/FIX levels. There was a significant but weak negative correlation between BS and factor level (Spearman's r2 = −0.36, P < 0.001).
Conclusion
Our results show that haemophilia carriers experience abnormal bleeding, including haemarthrosis. Overall, BS in women with Type 1 VWD > haemophilia carriers > Type 3 VWD OC > controls. Understanding the performance of the ISTH‐BAT in this population is a critical step in future research aimed at investigating the underlying pathophysiology of abnormal bleeding, with the ultimate goal of optimizing treatment.