The proportion of young male hemophilia patients who underwent ultrasound examinations: an observational study using a nationwide claims database.

Background: Advances in hemophilia treatment have reduced bleeding episodes in patients with hemophilia (PWH) and improved their musculoskeletal prognosis; however, complete prevention of musculoskeletal disorders has not been achieved. Recently, the usefulness of ultrasound (US) examinations in the musculoskeletal assessment of PWH has been reported, but the actual use of US has been suggested to be limited. The aim of this study was to clarify the extent to which US is being performed on young male PWH at medical institutions in Japan.

Methods: This was an observational study using the National Database of Health Insurance Claims and Specific Health Checkups of Japan. We identified almost all male PWH aged under 30 years who were prescribed hemostatic agents between 2015 and 2021 in Japan. For each year, we calculated the proportion of PWH who underwent US and, as a sensitivity analysis, the proportion of PWH who underwent US examinations for musculoskeletal disease. The Cochran‒Armitage trend test was used to examine changes in the number of PWH who underwent US examinations over the observation period. The Lorenz curves and Gini coefficients were calculated from the proportion of US examinations performed at each medical institution annually.

Results: A total of 2137-2483 male PWH younger than 30 years were identified annually. The annual proportion of PWH who underwent US ranged from 6.1 to 12.9%. By age group, the annual proportions of US were 6.7-14.4%, 8.1-16.6%, and 2.0-8.7% for 0-9, 10-19, and 20-29 years, respectively. The annual proportions of musculoskeletal US were 2.9-7.7%. The proportion of PWH who underwent US increased significantly over the seven-year period; however, it varied by medical institution (Gini coefficients 0.85-0.92).

Conclusions: The use of US for young PWH is becoming more widespread in Japan. However, US is performed at different rates among medical institutions.