EPIDEMIOLOGY OF INHIBITORS IN HEMOPHILIA-A

One of the most serious complications of the treatment of haemophilia A is the development of inhibitors. Former studies mostly considered t he prevalence of inhibitor development, thus underestimating its true risk. Prevalences ranged widely (7-18%) probably due to the population s studied and the study design. Recent prospective previously untreate d patients (PUP) studies were more comparable because of similar study designs. Eight PUP studies regarding the incidence of factor WI inhib itors were analyzed: The inhibitor incidences (Independent of severity of haemophilia) ranged from 18.4 to 28%. Evaluating only severe haemo philiacs (factor VIII < 2%) significantly higher incidences were found . After 9-36 exposure days (as medians inhibitor development occurred at 0.8-3.3 years of age (as medians).