The changing patterns of factor VIII (FVIII) and factor IX (FIX) clotting factor usage in a comprehensive care centre between 1980 and 1994.

The annual amount of clotting factor used by patients at the Royal Free Haemophilia Centre increased significantly from 4 million iu in 1980 to over 15 million iu by 1994 (P < 0.0001). In order to assess the reasons for this increase, data on concentrate usage over this period were retrospectively collected for patients who had haemophilia or von Willebrand's disease. Only patients who were registered exclusively at the Centre were included in the study. In total, 498 patients met the inclusion criterion. The median age of the cohort on 1 January 1980 was 21 (range < 1-69) years. During the period there were 88 births and 45 deaths. The majority of patients had haemophilia A (55%). The median follow-up period per patient was 2.1 (range 0-14.8) years. Despite adjusting for increases in the number of patients and changes in body weight, statistically significant increases in clotting factor usage were detected for some subgroups of patients, in particularly for those with severe haemophilia A and B and from the late 1980s onwards, for patients with von Willebrand's disease. Two reasons for this increase in clotting factor usage were identified as being the introduction of improved products and prophylaxis. However, the increased cost of clotting factor provision that has resulted from these changes in treatment policy should not be analysed in isolation but should be balanced off against cost decreases in other areas and against increases in the effectiveness of treatment.