An overview of current trends and gaps in patient-reported outcome measures used in haemophilia

Aim: This review summarises the importance, recent progress and issues in measuring patient-reported outcomes (PROs) in haemophilia research. Methods: A critical review of recent advances and trends in measuring haemophilia-related PROs was conducted, using current regulatory guidelines and methodological recommendations to evaluate these instruments. Results: Although regulators, payers and policymakers increasingly consider the patient's perspective to be important in treatment decision-making, to date, few haemophilia intervention studies have meaningfully applied PRO endpoints. Condition-specific PRO instruments have been developed, but most are not fully validated; sensitivity to subgroup differences and changes over time is unclear. Generic PROs and instruments developed for other conditions have been used to measure health-related quality of life (HRQL) in haemophilia patients, but little evidence of their validity for this purpose exists. Haemophilia presents a number of challenges to developing valid, reliable and responsive PRO instruments, including the rarity of the disorder; necessitating research in multiple counties to attain sufficient sample size; the chronic nature of the condition; acute exacerbations of illness; age and geographical region variations with respect to treatment; differences in treatment regimens, range of disease severity and phenotypes; and changes in patients' perceived health status over time. Given that haemophilia begins at birth, the illness has an impact on the lives of caregivers, although the extent of the impact is largely unknown. Conclusions: Patient perspectives are crucial to understanding the best and most cost-effective haemophilia treatment approaches. More research is needed on the ability of current disease-specific and generic PRO instruments to capture responsiveness to treatments over time and subgroup differences in outcomes. Inclusion of PROs in clinical trials is necessary to answer these questions.