Preferences and Health-Related Quality-of-Life Related to Disease and Treatment Features for Patients with Hemophilia A in a Canadian General Population Sample

Background: Current treatments for hemophilia A in Canada include on-demand treatment as bleeds occur and regular intravenous prophylactic factor VIII (FVIII) infusions. The subcutaneous therapy emicizumab was recently approved for treatment of hemophilia A. The objective of this study was to estimate utility values associated with hemophilia A health and treatment states from a Canadian societal perspective, including preferences related to treatment efficacy and frequency and route of administration.

Methods: A vignette-based time trade-off (TTO) utilities elicitation was undertaken in Canadian adults to compare preferences for six hemophilia health states describing prophylactic and on-demand treatment, with varying bleed rates and frequency of treatment administration. A convenience sample was recruited via market research panels and snowball sampling. Health state/vignette definitions were informed by clinical experience, clinical trial results regarding bleed frequency, and validated by qualitative interviews of hemophilia patients and caregivers (n=10). Utilities were estimated via an online, trained interviewer-guided, vignette-based TTO exercise, where respondents valuated health states describing hemophilia patients (adults or children) receiving subcutaneous prophylaxis, intravenous prophylaxis, and on-demand treatments. Analyses included a descriptive analysis by health state; a mixed-effects analysis of utility values adjusted for subcutaneous vs infusion-based therapies and number of bleeds; and for prophylactic regimens, an analysis of utilities by frequency of infusions or injections.

Results: TTO interviews were conducted with 82 respondents. Mean utilities [95% CI] were highest for subcutaneous prophylaxis (0.90 [0.87-0.93]), followed by intravenous prophylaxis (0.81 [0.78-0.85]), and on-demand treatment (0.70 [0.65-0.76]). In regression analysis, subcutaneous treatment health states were associated with a utility increment of +0.1112. Additional bleeds and more frequent infusions were associated with lower utility values (-0.0027 per bleed and -0.0003 per infusion).

Conclusion: Subcutaneous prophylaxis is associated with higher utility values compared to intravenous prophylactic and on-demand treatment, while increased bleeds and infusions are associated with reduced utility.