The Quality of Life of Spanish Patients with Huntington's Disease Measured with H-QoL-I and EQ-5D

Background and objective: Huntington's disease (HD) is an inherited neurodegenerative disorder that heavily affects the patient's motor, cognitive, and psychological functions. Yet, very few studies have measured the impact of this disease on the patient's health-related quality of life (HRQoL) with specific and validated instruments. The aim of this study was to explore the impact of HD on the HRQoL of Spanish HD patients using the self-reported, Huntington Quality of Life Instrument (H-QoL-I) and the generic instrument EuroQoL five dimensions (EQ-5D-3L) and thereafter compare the results obtained with the two instruments. Methods: Fifty-five patients and an equal number of caregivers participated. Patient assessments included the questionnaires of the Huntington Self-Assessment Instrument's four parts: background information assessment, Huntington clinical self-reported instrument, disease-specific HRQoL assessment (H-QoL-I instrument) and Huntington resource utilisation interview, and the EQ-5D-3L questionnaire. Levels of disease severity were also determined based on the Unified Huntington's Disease Rating Scale that was completed by caregivers. Pearson's correlation tests were computed between H-QoL-I and EQ-5D-3L scores. Results: The scores obtained with the H-QoL-I instrument showed that motor dimension was the most altered followed by the psychological dimension while the social dimension was the least altered. Increase of disease severity resulted in lower patient QoL. The usual activities and anxiety/depression were the most severely altered dimensions according to the EQ-5D-3L results. Mobility was also altered to a great extent while pain was the least altered dimension. All correlations between H-QoL-I and EQ-5D-3L scores were moderate to high and statistically significant (p<0.01) with the exception of the correlation between H-QoL-I socialising score and EQ-5D-3L anxiety score. The highest correlations were found between H-QoL-I motor score and three EQ-5D-3L scores: mobility, self-care, and usual activity. Conclusions: The quality of life of the Spanish HD patients included in this study was severely affected by HD as demonstrated by the results of the generic EQ-5D-3L and the specific H-QoL-I instruments, which showed considerable impact of the disease on the motor and psychological functions. The H-QoL-I instrument was able to discern psychological and motor functioning dimensions that were altered by the disease with more specificity and accuracy than the generic instrument.