Risk of bleeding associated with physical activity in boys with haemophilia (BLEEDS)

This study will quantify the magnitude of the risk of bleeding associated with physical activity in boys with haemophilia.

Methods

The study uses a case-crossover (case-only) design. 84 boys will participate in the study for one year. During the study period participants will be interviewed after each bleed to ascertain exposures to physical activity in a ‘case window’ immediately preceding the bleed and in a ‘control window’ 24 hours earlier.

The ratio of exposures to physical activity in the case and control windows provides a measure of the risk associated with physical activity.