The Spanish version of the dementia quality of life questionnaire: a validation study

Background: The aim of the study was to adapt and validate culturally the dementia-specific health-related quality of life instrument (HRQoL) into Spanish for patients with mild to moderate dementia.

Methods: Two forward translations, a reconciled version, and then a back translation were completed and subjected to expert review. A total of 112 patients with dementia, diagnosed according to DSM-IV criteria, from six centres providing care for persons with dementia in Spain participated in the study. The following patient-reported information was obtained by interview: demographics, subjective perception of health, depressive symptoms (Geriatric Depression Scale-15; GDS-15), functional ability (Barthel Index), and both generic (World Health Organization Quality of Life; WHOQOL-BREF) and dementia-specific quality of life (DQoL).

Results: The Spanish version of the DQoL showed acceptable psychometric properties. Internal consistency (Cronbach's alpha) was acceptable for most of the DQoL scales. As expected, associations were found between DQoL scales and the WHOQOL-BREF psychological domain and the GDS-15, indicating good validity. Neither functional status nor severity of dementia was associated with QoL; but depressive symptoms and self-reported feeling ill had a negative association on QoL.

Conclusions: The results showed that the Spanish version of the DQoL has comparable psychometric properties to the US version. The DQoL appears to be a reliable and valid instrument intended to be administered to patients with mild/moderate dementia who are living at home.