Instruments measuring the disease-specific quality of life of family carers of people with neurodegenerative diseases: a systematic review

OBJECTIVE: Neurodegenerative diseases, such as dementia, have a profound impact on those with the conditions and their family carers. Consequently, the accurate measurement of family carers' quality of life (QOL) is important. Generic measures may miss key elements of the impact of these conditions, so using disease-specific instruments has been advocated. This systematic review aimed to identify and examine the psychometric properties of disease-specific outcome measures of QOL of family carers of people with neurodegenerative diseases (Alzheimer's disease and other dementias; Huntington's disease; Parkinson's disease; multiple sclerosis; and motor neuron disease). DESIGN: Systematic review. METHODS: Instruments were identified using 5 electronic databases (PubMed, PsycINFO, Web of Science, Scopus and the International Bibliography of the Social Sciences (IBSS)) and lateral search techniques. Only studies which reported the development and/or validation of a disease-specific measure for adult family carers, and which were written in English, were eligible for inclusion. The methodological quality of the included studies was evaluated using the COnsensus based Standards for the selection of health Measurement Instruments (COSMIN) checklist. The psychometric properties of each instrument were examined. RESULTS: 676 articles were identified. Following screening and lateral searches, a total of 8 articles were included; these reported 7 disease-specific carer QOL measures. Limited evidence was available for the psychometric properties of the 7 instruments. Psychometric analyses were mainly focused on internal consistency, reliability and construct validity. None of the measures assessed either criterion validity or responsiveness to change. CONCLUSIONS: There are very few measures of carer QOL that are specific to particular neurodegenerative diseases. The findings of this review emphasise the importance of developing and validating psychometrically robust disease-specific measures of carer QOL.