Advancements in haemophilia A and health equity: is it time to redefine severity?
Primary prophylaxis to prevent spontaneous bleeds and development of haemophilia arthropathy was first recommended by the World Federation of Hemophilia (WFH) in 1994 for people with severe haemophilia A (ie, factor VIII <1%).1 Haemophilia severity has been defined by factor VIII concentrations, based on a 1958 paper describing the relationship between bleeding and factor concentrations in 135 patients,2 although the fact that there is heterogeneity within these severity thresholds is recognised.