Comparison of QoL-AD and DQoL in elderly with Alzheimer's disease.

OBJECTIVE: The Dementia Quality of Life (DQoL) and the Quality of Life in Alzheimer's Disease (QoL-AD) are the two most widely used dementia-specific QoL instruments in the world. We aimed to compare the psychometric properties of these two instruments and identify which is most adapted to use in geriatric consultations. METHODS: To evaluate the psychometric properties of the French language validation of DQoL and QoL-AD, 123 patients aged 65 years and over suffering from AD (Mini Mental State Examination score ≥10) were recruited in seven French hospitals and one Switzerland hospital. The DQoL comprises 29 items, ranked on a five-point Likert scale and measuring five QoL domains: self-esteem, positive affect, negative affect, feeling of belonging and sense of aesthetics. The QoL-AD contains 13 items giving an overall score ranging from 13 to 52 and evaluating the domains of interpersonal relationships, financial difficulties, physical condition, memory, mood and overall health. RESULTS: Both questionnaires showed adequate reproducibility at 2 weeks interval (intra-class correlation coefficient >0.80), good internal consistency (Cronbach's alpha coefficient >0.70) and good convergent validity with the general health dimension of the Duke Health Profile. The time required to complete the QoL-AD was significantly shorter (p < 0.0001). DQoL had better discriminant capacity (with at least one dimension significant for each subgroup of severity of cognitive decline, dependency, presence of depression or behavioural disorders). CONCLUSIONS: For quick evaluation of QoL during consultations in geriatric care, the QoL-AD is preferable, whereas for the purposes of research and more in-depth evaluation, the DQoL is more suitable.