Michael Hurd and colleagues, using data from the Health and Retirement Study, reported last week in the New England Journal of Medicine that the annual direct cost for Alzheimer disease in 2010 was $109 billion for an estimated 3.8 million people in the US who have the illness. (Monetary Costs of Dementia in the United States,http://www.nejm.org/doi/full/10.1056/NEJMsa1204629) This is a staggering number, about as high as the costs for cardiovascular disease, and more than 20% of the Medicare budget.
The importance of this study, however, is not how large the costs are but how much less they are than those estimated by the Alzheimer’s Association, an even more staggering $172 billion. One of several reasons for the $63 billion difference is that the investigators’ estimate of the number of Americans with Alzheimer’s disease also was much lower than the numbers offered by the Alzheimer’s Association, 3.8 million compared to the Association’s 5.2 million. The 1.4 million difference is huge as well. For example, it’s about the number of people with Parkinson disease.
The news is in the discrepancies between the investigators’ and the Alzheimer’s Association’s estimates. One of these estimates is off by at least $31.5 billion and 700,000 people; and that’s concerning. If we can’t size even the rough magnitude of people with Alzheimer disease and costs, then it’s hard to plan. If numbers are inflated and used to raise funds and to lobby then we lose substantial credibility.