OBJECTIVES: No specifi c health-related quality of life (HRQOL) instrument tool is
available for Huntington’s disease (HD). In the context of a large European study on
HD burden (Euro-HDB), a specifi c HRQoL tool (HQOLI) was created for patients in
early and intermediate stages of HD. We describe the development and psychometric
validation of HQOLI. METHODS: After semistructured interviews with patients,
caregivers, and HD specialists, we ran a patient focus group. a self-reported questionnaire
was then devised in French language. The questionnaire consists of 42 items,
relating to 11 dimensions: Mobility, Motor Ability, Autonomy 1 and 2, Finance,
Occupational Activities, Psychology, Feelings of Guilt, Vitality, Socializing, and Body
Image. Face validity and internal and external validity were examined. RESULTS:
Among 178 participating patients, 15 did not complete HQOLI. Item response rates
range from 0.81 to 0.98, excluding the occupational activities domain. As expected,
there is a ceiling effect on several items, suggesting low sensitivity at advanced HD
stage. Cronbach’s alphas are greater than 0.76. HQOLI total score is highly correlated
with generic HR-QOL (SF36 and EQ5D) as well as with the specifi c caregiver HRQoL
instrument (HDQoL-C). Correlations were -0.73 (P < 0.01) with EQ5D utility, -0.76 (P < 0.01) with "Physical Functioning," and -0.74 (P < 0.01) with "Mental Health." Voluntary movement, fall/balance, and dystonia symptoms contribute signifi cantly to HQOLI (P = 0.01), but chorea does not (P = 0.21). CONCLUSIONS: These data support the validity of the HQOLI in patients with HD. The ceiling effect limits the use of HQOLI in late stages but appears necessary to achieve good discrimination at early and intermediate stages. Correlations with other instruments suggest good external validity. High correlations of several items within dimensions suggest item number can be reduced. a new, shorter version of the questionnaire is in development. Assessments of responsiveness to change, test-retest reliability, and cross-cultural validation will be performed/are underway.