High-Impact Physical Activity Increases Bleeding Risk in Children with Hemophilia

Children with severe hemophilia have avoided vigorous physical activity. Researchers in Australia conducted a case-crossover study to examine bleeding episodes requiring clotting factor administration in 104 children (age range, 4–18 years) with severe (<1%) or moderate (1%–5%) clotting factor level following physical activities categorized according to expected frequency and severity of collisions.

During 4839 person-weeks of follow-up (median, 52 weeks), 336 bleeding episodes occurred in 84% of participants. Compared with control periods of inactivity or low-risk (category 1) activity (e.g., swimming), category 2 activity (e.g., basketball) was associated with significantly increased risk for transient bleeding (odds ratio, 2.7). Exposure …