Age at first joint bleed and bleeding severity in boys with severe hemophilia A: Canadian Hemophilia Primary Prophylaxis Study.

摘要

Hemophilia A is an inherited bleeding disorder caused by coagulation factor (FVIII) deficiency. A circulating FVIII level of <= 1% defines the severe phenotype and the risk for spontaneous, recurrent hemarthroses that often progress to disabling arthropathy [1]. Factor prophylaxis, given every other day, reduces joint bleeding and prevents arthropathy but is very costly [2,3]. Cost-effective prophylaxis may involve tailoring treatment to individual clinical needs [4]. Approximately 10% of individuals with severe hemophilia A bleed less than expected and the reasons are not completely known [5]. Some correlates with reduced bleeding have been postulated. For example, boys with an older age at first joint bleed may bleed less frequently and require less FVIII compared with those who have an earlier first joint bleed [6]. Using data from an ongoing prospective trial of boys with severe hemophilia A treated with tailored primary prophylaxis, we asked: does age at first joint bleed and/or protocol adherence predict bleeding risk?