OBJECTIVES : Regulatory agencies may share data internationally to inform decision-making regarding orphan drug treatments, giving local research potentially global impact. This study explores the responsiveness and acceptability of the widely-used EQ-5D in measuring health-status across an international sample of Duchenne muscular dystrophy patients and caregivers.

METHODS : A community-engaged cohort study is documenting the experience of adults with Duchenne, caregivers of affected adults, and caregivers of minors from Australia, Belgium, Canada, Holland, United Kingdom, & United States (expected N=360). Participants completed the EQ-5D (3L, 3LProxy1, YProxy1). ANOVA tests explored QALY and VAS scores across respondent groups and country, and regression explored scores adjusted for patient-age and significant independent predictors. Z-tests of Likert-type items evaluated the EQ-5D for ease of understanding and answering, relevance, and reflection of “real health” in comparison with a 75% agreement-rate.

RESULTS : A preliminary sample of 22 adults, 24 caregivers of adults, 69 caregivers of minors from Australia, UK, and US participated. QALY and VAS scores were predicted by participant role (P<0.001), but not by country (P>0.05). The mean QALY was 0.37 (range: 0.16, 0.79) for adults, 0.18 (-0.11, 0.67) for caregivers of adults, and 0.47 (-0.11, 1.0) for caregivers of minors. Adults reported QALY scores 20% higher than caregivers of adults (P=0.01) after age-adjustment. The mean VAS score was 79 (range: 30, 99) among adults, 55 (15, 90) among caregivers of adults, and 68 (30, 100) among caregivers of minors. Adults reported average VAS scores 24 points above caregiver groups after age adjustment (P<0.01). All groups met or exceeded the 75% instrument acceptability agreement-rate (P<0.05).

CONCLUSIONS : EQ-5D was responsive and acceptable for this multi-national rare disease sample. While adults consistently rated their health higher than caregivers in preliminary data, the difference between groups was attenuated using the population-derived QALY estimates as compared to self-evaluation using the VAS.