Factor activity levels and bleeding scores in pediatric hemophilia carriers enrolled in the ATHNdataset.

Abstract

Multiple studies have now shown that a significant proportion of hemophilia carriers meet the criteria for having hemophilia and/or report abnormal bleeding. However, to date, investigations of hemophilia carriers have almost exclusively involved women over 18 years of age. Little is known about factor activity levels and bleeding scores in carriers during childhood. We queried a large deidentified database of subjects with bleeding disorders residing in the United States to determine factor activity levels and bleeding scores. The ATHNdataset was queried for hemophilia carriers under 18 years of age. Collected information included demographics, factor activity levels, and bleeding scores. Over 700 carriers in the pediatric age group were identified, of which 626 submitted factor activity levels. Nearly half had factor activity levels less than 40IU/dL, thereby meeting criteria for having hemophilia. Of those reporting bleeding scores, only 13.5% reported an abnormal bleeding score for age. The proportion reporting abnormal bleeding scores was higher in those with factor levels less than 40IU/dL (23%) than those greater than 40IU/dL (9.7%). The proportion of pediatric carriers with hemophilia was double of that previously reported for adults. Of those with hemophilia reporting a bleeding score, the majority (77%) did not report an abnormal bleeding score for age. However, nearly 10% of pediatric carriers not meeting criteria for having hemophilia reported abnormal bleeding scores for age. Similar results are reported in adults suggesting that factor activity levels may not be predictive of bleeding symptoms in carriers.