A cohort study of the usefulness of primary prophylaxis in patients with severe haemophilia A.

Primary prophylaxis is a method of haemostatic management to prevent bleeding and arthropathy in patients with severe haemophilia. The aim of this study was to evaluate the usefulness of primary prophylaxis in patients with severe haemophilia A. This study included 15 patients with haemophilia A who received primary prophylaxis at our institution for a minimum of 5 years. We evaluated the annualized bleeding ratio of joints or other sites, current joint function, and X-ray images and MRI scans taken when patients were 6 years old. The range of patients' ages at the end of the study was 6.2-16.8 years, and at the start of primary prophylaxis it was 0.8-2.4 years. Factor VIII concentrates (25-40 units kg(-1) dose(-1)) were administered 3 times/week or every other day, according to the Swedish protocol. Mean joint and non-joint annualized bleeding ratios were 0.49 ± 0.5 and 1.54 ± 1.69, respectively. At the final evaluation, all patients displayed a normal range of motion for both elbows, knees, and ankles. The radiography and MRI findings at the age of 6 were unremarkable in all patients. Overall, primary prophylaxis for patients with severe haemophilia A was performed safely, reduced the number of bleeding events, and prevented progression to arthropathy.