Background: Costs of care are frequently included as secondary endpoint in Alzheimer clinical trials because payers demand evidence of the budgetary effects of novel therapies. Future clinical trial protocols can be optimized on the basis of the currently available data, including what are the key resources and how are they correlated to disease severity measures. Methods: Primary patient-level data from two 18 months clinical trials of a putative disease modifier in mild-to-moderate Alzheimer's disease (n = 2,744) were analyzed to identify key components of costs of care and their determinants in a clinical trial setting. Costs of care were assessed with the resource utilization in dementia Lite (RUD) instrument, which includes patient accommodation, informal care, community care, and hospitalizations. The contribution of each component to total costs of care and their correlation with one another and key disease severity measures (Alzheimer's Disease Assessment Scale Cognitive Subscale, Mini-Mental State Examination, Clinical Dementia Rating Sum of Boxes, Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory, and Neuropsychiatric Inventory Questionnaire) was explored. Results: Informal care constituted 82% to 86% of the total costs of care over the 18-months trial and community care services and patient accommodation contributed 6% to 8% each. Informal care was positively correlated with hospitalizations but negatively to patient accommodation, indicating that these services are supplements. Informal care also had the strongest pair-wise correlation with key disease severity measures, suggesting a higher chance of identifying a treatment effect on this component. ADL-ability (Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory) was the strongest predictor of costs of care of all disease severity measures. Conclusions: Informal care is the most important component of costs of care in a mild-to-moderate Alzheimer clinical trial sample, and it is primarily driven by the ADL-ability of the patient. Investigators should focus on the assessment of this economic endpoint because a significant treatment effect on this resource is likely to also affect total costs of care. (C) 2011 The Alzheimer's Association. All rights reserved.
