A survey of factor prophylaxis in boys with haemophilia followed in North American haemophilia treatment centres

A survey was conducted in 2002 to determine the pattern of factor prophylaxis use in boys less than or equal to18 years of age with haemophilia followed in North American treatment centres. Responses were obtained from 4553 cases (74% haemophilia A, 26% haemophilia B). The frequency of prophylaxis, defined as factor infusion greater than or equal to once per week for greater than or equal to45 weeks per year, was significantly higher for haemophilia A vs. haemophilia B cases (51% vs. 32%, P < 0.0001), and for boys with severe haemophilia A living in Canada vs. the USA (77% vs. 47%, P < 0.0001). Use of full-dose prophylaxis, defined as the infusion of 25-40 IU kg(-1) of factor VIII on alternate days (minimum three times per week) or 25-40 IU kg(-1) of factor IX twice weekly, was similar for boys less than or equal to5 years of age in both Canada and the USA (30% and 33% haemophilia A and 35% and 13% haemophilia B). Reasons for initiating prophylaxis included a history of joint bleeding (88%) and age less than or equal to2 years (23%). For prophylaxis triggered by joint bleeding, 38% of haemophilia treatment centres indicated that they would initiate prophylaxis after the first joint bleed and 66% after a history of target joint bleeding, defined most frequently as 2-4 bleeds over a 3-6 consecutive month period. A central venous line was used to ensure easy venous access for full-dose prophylaxis therapy in 80% of boys less than or equal to5 years of age. These data offer a basis for projecting long-term factor concentrate needs for persons with haemophilia living in North America.