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.