Factors Influencing Sport-Induced Bleeding in Patients With Haemophilia Without Inhibitors: A Single Centre Retrospective Study of People Born in the 2000s.

introductionRecent advances in prophylaxis with clotting factor concentrates have enabled people with haemophilia (PwH) to participate in high-intensity exercises; however, this does not preclude them from sports-induced bleeding (SIB).

aimTo investigate factors influencing the recent occurrence of SIB among PwH.

methodsThis retrospective study included 23 inhibitor-negative PwH born between 2000 and 2009. Patient information, including participation in sports and the frequency of bleeding, was investigated using medical records.

resultsOf the 23 patients, two and 18 participated in sports once or twice/week and at least three times/week, respectively, and only three did not regularly participate in sports. The top three sports were baseball, swimming, and soccer. A total of 57 SIB events were identified in 15 patients. The bleeding sites were the joints (20 times), intramuscular (24 times) and subcutaneous (13 times). SIB occurred more commonly among junior high school students (13-15 years old). The incidence of the SIB in PwH participating in sports at least three times a week was significantly higher than that in others (p = 0.033), whereas no association was observed between the severity of haemophilia or types of sports and the frequency of SIB.

conclusionSports participation frequency may be a risk factor for SIB in inhibitor-negative PwH, although the small sample size may make it difficult to generalise the results of this study. Regardless of disease severity, PwH-especially junior high school students-should regularly consult with their attending physician and receive individualised treatment based on activity level to prevent SIB. PLAIN LANGUAGE SUMMARY: Haemophilia is a rare bleeding disorder that mainly affects boys and is caused by a lack of certain proteins (factor VIII or IX) that aid blood clotting. In the past, PwH were often told to avoid exercise because even normal activities could cause serious bleeding. However, modern treatments that prevent bleeding episodes (prophylaxis) enable PwH to participate in sports. In this study, we examined sports-related bleeding in 23 Japanese boys with haemophilia born between 2000 and 2009 to determine risk factors for bleeding. The findings showed that how often the boys played sports-particularly more than three times per week-was a stronger predictor of bleeding than how severe haemophilia was in our cohort. Regardless of sports type, most bleeding episodes happened during junior high school years, when physical growth, new sports participation, and intense physical activity are common. In our cohort of individuals with haemophilia, engaging in sports at least three times per week was associated with an increased risk of SIB, highlighting the importance of tailoring treatment plans to individual activity patterns.