Alzheimer's disease (AD) affects the cognitive function and capacity for independent living of the elderly, however little is known about the measurement of patient's overall health-related quality of life (HRQoL) and its relationship to these effects. We examined the relationship between patient/caregiver-rated HRQoL and cognition (using the Mini-Mental State Examination (MMSE)) or Instrumental Activities of Daily Living (IADL). One hundred AD patients participating in an open-label trial of donepezil were followed for 6 months. Cognition and function were assessed using the MMSE (clinician-rated) and IADL scale (caregiver-rated). Patient QoL, as assessed by the Assessment of Quality of Life (AQoL) scale, was rated separately by patients and their primary caregivers. Mean patient-rated AQoL was 0.60, whilst caregiver-rated AQoL was 0.50. Patient and caregiver AQoL assessments correlated (r = 0.37, P = 0.0038) for all levels of disease severity. Patient-rated AQoL scores ranged from 0.52 for patients with severe AD, to 0.71 for patients with mild AD. Caregiver-rated AQoL scores ranged from 0.40 to 0.59. There were approximately linear relationships between the AQoL and MMSE scores (patient-rated r = 0.30, P < 0.0001; caregiver-rated r = 0.28, P < 0.0001), and AQoL and IADL scores (patient-rated r = 0.36, P < 0.0001; caregiver-rated r = 0.43, P < 0.0001). Patient self-assessment of AQoL is a useful instrument for measuring HRQoL in AD that displays an approximately linear relationship with MMSE, IADL, and caregiver-rated AQoL.
Copyright 2004 Elsevier Ireland Ltd.