BackgroundSome studies suggest that people with haemophilia (PwH) who use prophylaxis value low frequency of clotting factor administration more than a lower risk of bleeding. However, more frequent infusions offer the potential of reducing joint disease and pain, which in turn may improve functioning and quality of life.AimsTo explore the impact on health-related quality of life (HRQoL) aspects of haemophilia associated with adherence and annual infusion rate in the context of factors influencing treatment that are important to patients, including prophylaxis, chronic pain, concomitant conditions and hospital admission.Materials and methodsHRQoL was assessed in participants with severe haemophilia in the ‘Cost of Haemophilia in Europe: a Socioeconomic Survey’ (CHESS) study who were using prophylaxis. Patients using on-demand treatment were excluded. This multivariate analysis examined the interaction between factors potentially influencing treatment and HRQoL, and minor and major bleeds.ResultsFrom the total CHESS population (n=1,285), 338 (26%) participants provided responses for major and minor bleeds and target joints, and 145 (11%) provided EQ-5D-3L responses. Major and minor bleeds were associated with pain. Patients with severe chronic pain reported a substantial negative impact on HRQoL; but this was significantly improved by increases in the annual infusion rate. This was not apparent in participants with mild or moderate pain.ConclusionIncreasing the frequency of prophylaxis infusions is associated with improved quality of life in PwH who have severe chronic pain. However, increasing the number of infusions per week in those with mild or moderate chronic pain with the intention of improving prophylactic effect may not have the same effect.