Dementias are one of the most expensive disease groups among the population aged 65 years and over. This is mainly due to the patients' deficits in activities of daily living which increase with the progression of dementia, leading to an increasing need for care. As a result, the costs of dementia may more than double over the course of the disease. The costs of medical care account for a relatively small share of total costs and are not greatly influenced by disease severity. By contrast, the costs of care make up at least three quarters of total costs in the majority of studies. When patients are cared for in the community, most of the care is often provided informally by relatives. Accordingly, up to 75 or 80% of the costs of illness in this setting, from a societal perspective, may be due to informal care. Additional professional home care accounts for a relatively small share of total costs. The costs of caring for patients who live in the community are directly related to the degree of functional impairment. By contrast, it can be difficult to estimate the costs which are specifically due to dementia in patients that are institutionalised.
