Clotting factor activity levels and bleeding risk in people with haemophilia playing sports

Background: Improved treatment options for people with haemophilia (PWH) have increased the possibilities for sports participation, but the risk of sports-induced bleeding (SIB) is still considered considerable by many. Aim: To assess sports associated injury- and bleeding risk in PWH and to assess clotting levels associated with safe sports participation. Methods: Sports injuries and SIBs were prospectively collected for 12 months in PWH aged 6–49 without inhibitors playing sports at least once weekly. Injuries were compared according to factor levels, severity, joint health, sports risk category and sports intensity. Factor activity at the time of injury was estimated using a pharmacokinetic model. Results: 125 participants aged 6–49 (41 children, 90% haemophilia A; 48% severe, 95% severe on prophylaxis) were included. Sports injuries were reported by 51 participants (41%). Most participants (62%) reported no bleeds at all and only 16% reported SIBs. SIBs were associated with factor levels at time of injury (OR: 0.93/%factor level (CI 0.88–0.99); p =.02), but not with haemophilia severity (OR: 0.62 (CI 0.20–1.89); p =.40), joint health, sports risk category or sports intensity. PWH with factor levels <10% during sports injury had a bleeding risk of 41% versus 20% in those with higher (>10%) factor levels. Conclusion: The results of this study emphasize the importance of clotting factor levels in prevention of bleeds. This information is vital for patient counselling and tailoring prophylactic treatment with clotting factors and non-replacement therapy.