Author Affiliations: Department of Pediatrics, Hemophilia and Thrombosis Center, University of Colorado and Children's Hospital Colorado, Aurora.
In this issue of JAMA, Broderick and colleagues1 report results of their study of the association of vigorous sports with bleeding rate in 104 children and adolescents with moderate or severe hemophilia. Most participants were receiving prophylactic infusions of replacement clotting factor, which has been established as the standard of care for children and adolescents with hemophilia.2,3 Activities were scored as category 1, 2, or 3, depending on the expected trauma related to frequency and severity of collisions associated with the activity; category 2 and 3 activities can be referred to as collision sports. The study results indicate that the risk of bleeding events requiring acute factor replacement was increased following collision sports, with an odds ratio of 2.7 for category 2 activities (such as basketball or baseball) and 3.7 for category 3 activities (such as wrestling or US football). However, because exposure time to the higher-risk activities was a small percentage of total life hours and because the annual rate of bleeding was low, the absolute increase in risk was low. Additional statistical modeling, in which factor level was inferred from infusion schedule and known recovery and half-life, revealed that each 1% increase in plasma factor activity was associated with a 2% lower bleeding risk, thus suggesting therapeutic strategies that might further reduce the bleeding risk associated with collision sports.
Manco-Johnson MJ. Collision Sports and Risk of Bleeding in Children With Hemophilia. JAMA. 2012;308(14):1480-1481. doi:10.1001/jama.2012.13303