Musculoskeletal health of subjects with hemophilia A treated with tailored prophylaxis: Canadian Hemophilia Primary Prophylaxis (CHPS) Study

Background Full-dose prophylaxis is very effective at minimizing joint damage but is costly. Tailored prophylaxis has been proposed as a way of reducing costs while still protecting joints. Objective To report detailed findings in index joints of 56 subjects with severe hemophilia A entered into the Canadian Hemophilia Prophylaxis Study, and treated with tailored prophylaxis, after 13years. Methods Boys with severe hemophilia A (<2% factor) and normal joints were enrolled between the ages of 1 and 2.5years. Initial treatment consisted of once-weekly factor infusions, with the frequency escalating in a stepwise fashion when breakthrough bleeding occurred. During the first 5years, subjects were examined every 3months using the modified Colorado Physical Evaluation (PE) scale; subsequently, every 6months. The Childhood Health Assessment Questionnaire (CHAQ) was administered at each visit. Results Median age at study entry was 19months (range 1230months); median follow-up was 92months (range 2156). The median PE score was 2, 3 and 3 at ages 3, 6 and 10years. Persistent findings were related to swelling, muscle atrophy and loss of range of motion. The median score for each of these items (for the six index joints) was 0 at ages 3, 6 and 10years. The median overall CHAQ score was 0 at ages 3, 6 and 10years, indicating excellent function. Conclusions Canadian boys treated with tailored primary prophylaxis exhibit minimal joint change on physical examination and minimal functional disability.