Dependence in Alzheimer's disease and service use costs, quality of life, and caregiver burden: the DADE study

BACKGROUND: Most models determining how patient and caregiver characteristics and costs change with Alzheimer's disease (AD) progression focus on one aspect, for example, cognition. AD is inadequately defined by a single domain; tracking progression by focusing on a single aspect may mean other important aspects are insufficiently addressed. Dependence has been proposed as a better marker for following disease progression. METHODS: This was a cross-sectional observational study (18 UK sites). Two hundred forty-nine community or institutionalized patients, with possible/probable AD, Mini-Mental State Examination (3-26), and a knowledgeable informant participated. RESULTS: Significant associations noted between dependence (Dependence Scale [DS]) and clinical measures of severity (cognition, function, and behavior). Bivariate and multivariate models demonstrated significant associations between DS and service use cost, patient quality of life, and caregiver perceived burden. CONCLUSION: The construct of dependence may help to translate the combined impact of changes in cognition, function, and behavior into a more readily interpretable form. The DS is useful for assessing patients with AD in clinical trials/research.