Background Proxy evaluation of patient health-related quality of life is relevant for Huntington's disease as there may be situations in which patient self-report is neither practical nor feasible.

Aims This study compares patient self-report of health-related quality of life, with that of their companion's/carer's proxy report of the patient's health-related quality of life.

Methods Data from a hundred and five pairs of persons living with Huntington's disease and their companions/carers contributed to this study. Patients were at different stages of Huntington's disease, ranging from at risk and gene positive presymptomatic individuals, to late stage disease.

Results Analyses showed that Patient-Proxy agreement was substantial to excellent for the Summary Scale score of the HDQoL, and also for most of its Specific Scales. There was a tendency for proxies to over-estimate internal emotional aspects of patients' health-related quality of life as better than patients' own ratings, while on more external physical and cognitive aspects the reverse was true.

Conclusions The proxy report version of the HDQoL is a useful complementary tool to patient HDQoL self-report, and appears to be a promising alternative when patients may be unable to self-report.