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Physical activity and the risk of bleeding in children with hemophilia

Clinical Question:
Does vigorous physical activity increase the risk of bleeding in children with hemophilia?

Bottom Line:
Vigorous physical activity among children and adolescents with hemophilia is associated with a significantly increased risk of bleeding episodes that require clotting factor injections. However, the overall risk is minimal; the average boy participating in 3 collision-prone physical activities weekly will only experience 1 additional bleeding episode per year. (LOE = 2b-)

Broderick CR, Herbert RD, Latimer J, et al. Association between physical activity and risk of bleeding in children with hemophilia. JAMA 2012;308(14):1452-1459.  [PMID:23047359]

Study Design:
Cohort (prospective)


Outpatient (specialty)

Children with hemophilia are commonly advised to avoid vigorous physical activity to reduce their risk of bleeding complications. These investigators identified 104 boys, aged 4 to 18 years, meeting standard criteria for moderate or severe hemophilia A or B. Eligible children and their parents or guardians monitored the occurrence of bleeding episodes that required treatment with clotting factors for up to 1 year following study entry. Similarly, they described all physical activities the boys engaged in for the 3 days preceding each bleeding episode, as well as the timing and dose of clotting factor injections in the previous week. Each participant served as their own control as investigators also randomly contacted them for episodes of "pseudobleeds" when they were asked the same questions about exposure to physical activity in the preceding 3 days. Each episode of physical activity was categorized according to standard criteria for expected frequency and severity of collisions, including category 1 activities during which significant collisions are not expected (eg, swimming); category 2 during which significant collisions might occur (eg, basketball), and category 3 during which significant collisions are unavoidable (eg, wrestling). Multiple analyses were performed to estimate the relative increase in risk of bleeds associated with various physical activities adjusted for estimated clotting factor levels (based on timing and dose of most recent injections). Follow-up occurred for a median duration of 52 weeks. A total of 336 bleeds occurred that met study criteria, with 84% of participants reporting at least 1 bleed, for an average incidence rate of 5.4 bleeds per person-year. The risk of a clinically relevant bleeding episode was significantly increased with category 2 activity (odds ratio [OR] = 2.7; 95% CI, 1.7-4.8) and category 3 activity (OR = 3.7; 2.3-7.3). However, the authors estimate that this level of risk increase correlates to an average boy (ie, a boy who bleeds 5 times yearly and is exposed to two category 2 activities and one category 3 activity weekly) having 1 bleeding episode as a direct result from the physical activity. Most bleeds associated with physical activity were clinically apparent within 1 hour following the episode.


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