Measuring health-related quality of life in Huntingtons' disease

Huntington's Disease (HD) is a fatal, neurodegenerative disease for which there is no known cure. The thesis describes the impact of Huntington's disease on health-related quality of life and reports the development and validation of the first disease specific questionnaire HDQ-D2 with established psychometric measurement properties which address the aspects of quality of life considered important to persons living with Huntington's disease. Literature review revealed that studies have relied on various generic health and quality of life instruments to measure patient experiences of living with HD. Generic instruments may not capture the reality of living with HD, address its specific aspects and measure its effect on the quality of life of persons sufficiently. A disease specific health-related quality of life (HRQOL) instrument may facilitate research into HRQOL in HD. The 40-item HDQ-D2 was developed on the basis of experiences of persons living with HD and consequently covers areas of concern which are of particular importance to this group. The development and validation process comprised three stages. In-depth interviews with 31 persons living with HD generated items for the item selection questionnaire (HDQ-D1). The 81-HDQ-D1 was administered to 313 persons living with HD in twelve different countries to select 40 items for HDQ-D2. Following pre-testing and pilot testing, the 40- item HDQ-D2 was administered to 261 persons living with HD for psychometric evaluation and assessment of measurement properties. Qualitative data was analysed systematically and sequentially. Statistical analysis of the HDQ-D1 and HDQ-D2 data utilized methods of Classical Test Theory and Item Response Theory in triangulation. The 40-item HDQ-D2 covers six key aspects of HRQOL of persons living with HD: cognitive, hopes and worries, services, physical and functional, mood state, self and vitality. It is an acceptable, reliable and valid instrument to measure the extent of impact of HD on the quality of life of persons living with the condition. HDQ-D2 as an instrument can be used for evaluation as well as for research and practice innovation. HDQ-D2 has three primary, six specific and an summary index scales. Thirty-eight of its items can be used to calculate six specific profile scores; thirty-five of its items can be used to calculate three primary profile scores; and twenty-one of its items can be used to calculate a summary index score. The primary and specific profile scores are useful for measuring the impact of interventions upon particular areas of HRQOL and the summary index score is relevant for evaluation of the overall effect of interventions on HRQOL. The development of HOQ-02 provides the option of using psychometrically based patient-generated questionnaires to measure quality of life of persons living with HO. The study contributed to the body of knowledge by designing the first disease specific instrument for measuring health-related quality of life in persons living with HO. For this reason, this newly developed disease specific HRQOL instrument for persons living with HO is a unique contribution to patient reported outcomes research and tools.EThOS - Electronic Theses Online ServiceGBUnited Kingdo