Impact of timing of prophylaxis commencement, F8 genotype and age on factor consumption and health-related quality of life in patients with severe haemophilia A.

Delayed prophylaxis start with intermediate dose intensity prevents bleeds but at a cost of more arthropathy and reduced HRQoL, compared to higher intensity primary prophylaxis. Non-null F8 genotype may allow lower factor consumption with similar HJHS and bleeding rates, compared to null genotype.