The influence of anosognosia and depression on the perceived quality of life of patients with Alzheimer's disease: a 12 months follow-up]

Introduction. Anosognosia and depression can influence perceptions of the patient's quality of life (QoL-p) in Alzheimer's disease (AD). Aim. To explore changes in perceived QoL-p in AD and the influence that depression and anosognosia can have on both patient and caregiver ratings. Patients and methods. Observational, analytical and longitudinal study over 12 months of a consecutive sample of 221 outpatients. Mean age was 77.8 +/- 7.3 years and there were 140 women (63.3%). Instruments: Quality of Life in AD, Anosognosia Questionnaire-Dementia, Geriatric Depression Scale, Disability Assessment for Dementia, Neuropsychiatric Inventory, Mini-Mental State Examination and Global Deterioration Scale. Effect size of the differences between two means was calculated, and a linear regression analysis involving the factors associated with perceived QoL-p was performed. Results. Patients with anosognosia had less depression and higher scores on the Quality of Life in AD, as compared with patients without anosognosia, and regardless of antidepressant drug treatment. Caregiver ratings of QoL-p were more negative. In the linear regression the largest discrepancies between patient and caregiver ratings of QoL-p were associated with anosognosia, depression, and functional status, factors that explained 35.3, 7.9 and 11.3% of the variance, respectively. Conclusions. Anosognosia was associated with less depression and better perceived quality of life in patients.