Alzheimer's disease costs: what we know and what we should take into account.

Background/objective: Alzheimer's disease (AD) is a very costly pathology. Total costs of AD result from the sum of direct and indirect costs. Intangible costs represent an additional burden that is difficult to quantify. This paper has reviewed the evaluation of the costs of AD and the methodologies to estimate them, and proposes the use of some tools which may be useful in establishing the financial weight of the disease.

Method: A systematic literature search was conducted using the Pubmed and Medline databases as a source of published papers.

Results: In AD, direct and indirect costs and their sum (total costs) are very high and tend to increase parallel with the evolution of the pathology. The evolution of AD is characterized by the loss of functional autonomy, the onset of behavioral and sleep disorders, and the development of delusions and hallucinations. This requires more frequent medical examinations and hospitalizations resulting in higher direct costs, which become the relevant weight. None of the papers reviewed investigated intangible cost.

Conclusion: The calculation of costs of AD is frequently based on cognitive decline and the degree of dependence of patients. The evaluation of intangible costs (psychological pain of the patient and of the unpaid caregivers' and their impaired quality of life) is a missing aspect in all reviewed studies. Due to the complexity of AD, it will be necessary to adopt cost evaluation systems including the different dimensions of the problem and its various aspects.