Validation of the Self-BAT (Self-Administered Bleeding Assessment Tool) and Evaluation of Determinants of Health in Hemophilia Carriers

Abstract

Hemophilia A and B are X-linked deficiencies of coagulation factor VIII and IX respectively. Males are affected, while females are carriers of the disease. Recently, it has become clear that more than a third of hemophilia carriers (HC) are symptomatic. Carriers may experience prolonged bleeding postpartum, following trauma and surgery as well as menorrhagia. This is the first research to incorporate both a bleeding assessment tool, to assist in objectively quantifying severity of bleeding symptoms, as well as a validated quality of life (QoL) questionnaire to facilitate an understanding of the relationship between bleeding symptoms and QoL. The objectives for this study are to validate a self-administered bleeding assessment tool (Self-BAT) as a screening tool to accurately identify HC with low factor levels (FL) and abnormal bleeding symptoms, to measure QoL of HC using the SF-36v2 and describe its relationship to bleeding severity and FL, and to investigate variability in FL. To date, 59 HC have been enrolled. A positive or abnormal Self-BAT bleeding score (≥6) has a sensitivity of 83%, specificity of 42%, a positive predictive value (PPV) of 0.48 and a negative predictive value (NPV) of 0.79 for the identification of HC with low FL. Analysis of QoL data shows an inverse correlation between QoL and BS (r=-0.52, p<0.0001). No significant relationship is observed between QoL and FL. This study found skewed X-inactivation ratio (XIR) to be significantly more prevalent in this population than has been observed in the general population. This suggests that determination of XIR may be useful in predicting risk of deficient FL. This study validates the Self-BAT as an effective tool to identify HC with low FL and/or abnormal bleeding symptoms. For HC, Self-BAT BS is a more accurate measure of bleeding severity and resultant QoL than FL. HC will benefit from treatment strategies aimed at controlling bleeding symptoms which will facilitate improvements in the management of these patients overall.