Introduction: Treatment adherence is critical to minimize bleeding episodes in persons with haemophilia. Suboptimal adherence increases risk of adverse medical outcomes and negatively impacts quality of life. Assessment of treatment adherence is therefore an integral component of intervention to mitigate the adverse impacts of haemophilia.
Aim: To develop and validate a multifactorial, patient (self or caregiver) report adherence measure for emicizumab treatment and report the first patient-report data on adherence to specific components of emicizumab treatment (dosing, timing, injection, planning and bleeds).
Methods: An IRB approved multi-site prospective study enrolled 83 participants with factor VIII deficiency being treated with emicizumab. Participants completed the 25-item VERITAS NexGen (self-report from 50 adults age 18+ years; caregiver-report from 33 parents of children aged 6 months to 17 years) as well as a global adherence rating (GAR) scale. Providers of participants also completed a GAR scale.
Results: Most VERITAS-NexGen subscales had good-to-excellent internal consistency reliability, test-retest reliability, and validity. VERITASNexGen scores revealed globally strong patient-reported adherence; however timing and bleed management were reported as greater challenges to adherence compared to dosing and injections. Adults struggled more with timing and planning of injections than caregivers.
Conclusion: The VERITASNexGen is the first validated multifactorial patient-report measure of adherence designed specifically for emicizumab treatment. Results suggest excellent adherence, with only 4%-13% of participants reporting suboptimal adherence to different components of the treatment regimen. Used in conjunction with other adherence measures, VERITAS-NexGen meets a crucial need for monitoring and understanding patient adherence to emicizumab in clinical and research settings.
Keywords: adherence; emicizumab; haemophilia; psychometrics; reliability; validity.
© 2023 John Wiley & Sons Ltd.