Factor Activity Levels and Bleeding Scores in Pediatric Hemophilia
Carriers Enrolled in the ATHNdataset.
Abstract
Background: Multiple studies have now shown that a significant
proportion of hemophilia carriers meet 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.
Procedures: The ATHNdataset was queried for hemophilia carriers
under 18 years of age. Collected information included demographics,
factor activity levels, bleeding scores. Results: 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 40 IU/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 40 IU/dL (23%)
than those greater than 40 IU/dL (9.7%). Conclusions: 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.