Clinical prediction models for inhibitor development in severe hemophilia A


H. Marijke van den Berg, Department of Laboratory and Pharmacy, University Hospital Utrecht, Utrecht, the Netherlands.
Tel.: 31 30 250 8456; fax: 31 30 250 5438.


Summary.  Clinical prediction models for factor VIII inhibitor development may potentially facilitate the identification of patients at high risk of this complication. In particular, recognition of early intensive FVIII replacement therapy as a significant risk factor for inhibitor development has defined a clear clinical decision point that influences patient care. To assess the effect and potential acceptance of a prediction tool for FVIII inhibitor development in clinical practice, a 15-item survey was developed to assess whether these included items were accepted as potential risk factors by the health care providers taking care of these patients. The rating of these items was on a 5-point linear scale, with ‘1’ representing it to be very unlikely and ‘5’ very likely. Responses from 42 centers were available for analysis. These centers were responsible for taking care of 2642 children <18 years with severe hemophilia A. In addition to genetic factors (mean score ∼4.5), early intensive treatment was considered important for inhibitor development (mean score 4.07). Other factors likely to reduce inhibitor development were early onset of prophylaxis (mean score 3.68) and avoidance of early surgery (mean score 4.05). Physicians also agreed that institution of early prophylaxis and avoidance of elective surgery are important management strategies to reduce inhibitor development (mean scores 3.54 and 4.32, respectively).