Background Understanding and measuring the impact of Huntington’s on people’s lives is important to patients, families and care providers. However, questionnaires that are generic in origin are less likely to adequately reflect patient’s experience of living with Huntington’s. The Huntington’s Disease health-related Quality of Life questionnaire (HDQoL), is a disease-specific instrument that is fully patient-derived in order to maximise its relevance to patient’s lives. Aims The objective of this study was to refine and validate the HDQoL in a large sample of patients, and to elucidate health domains that are meaningful to patients. Methods Five-hundred and forty-one UK participants, from pre-manifest to end-stage disease completed the HDQoL, together with generic quality of life measures, and in-person motor, cognitive and behavioural assessments. The psychometric properties of the HDQoL were examined. Results The HDQoL has four domains comprising Physical-Functional, Cognitive, and two different behavioural aspects i.e. Mood-Self domain, as well as a distinct Worries domain. All domains showed good to excellent internal consistency. Known groups analyses illustrated significant and graded changes in clinical assessments and corresponding HDQoL domains across severity levels. Convergent and discriminant validity were demonstrated by the expected pattern of correlations between specific HDQoL domains and corresponding domain-relevant clinical assesments as well as patient-reported measures. The data demonstrate robust support for the refined HDQoL across disease stages. Conclusions The HDQoL is a relevant, reliable and valid patient-derived instrument to measure the impact of Huntington’s disease.
