The Alzheimer’s Association predicts that finding a drug treatment for memory loss could save families and the government $935 billion over 10 years. But its report tells only part of the story and ignores key costs, including costs of the therapy itself.

The group could have included an estimated price of those therapies in its report but chose not to, citing the uncertainties of any forecast. However, by excluding any estimate at all—or even a range of projected costs—it leaves out critical information and may inflate potential savings by tens of billions of dollars. In addition, it may also overstate the number of people who would benefit from an Alzheimer’s treatment.

In its new report, called “Changing the Trajectory of Alzheimer’s Disease: How A Treatment by 2025 Saves Lives and Dollars,” the group projects that by 2050, 13.5 million Americans will have the disease, and for about half, the condition will be severe. It estimates that in 2050 alone, their total medical and long-term care costs will exceed $1 trillion.

The Alzheimer’s Assn, like much of the Alzheimer’s establishment, advocates aggressively for federal funding for drug research.  And its report is a brief for the benefits of such treatments. But it is incomplete at best and misleading at worst.

Using a research model developed by the Lewin Group, a well-respected health care consulting firm, the Alzheimer’s Association estimated what would happen to the incidence of the disease and costs of care if a hypothetical treatment could delay the onset of dementia for five years. It assumes this therapy is introduced in 2025.

Under that scenario, the number of people with memory loss would fall from 13.5 million to 7.8 million by 2050, a decline of about 42 percent. Total costs would plunge by about one-third in 2050 alone. In the period 2026-2035, costs would decline by about $935 billion. Medicare costs would decline by $345 billion and Medicaid costs by $190 billion.

But the report ignores the cost of any new therapy, which could be enormous. An appendix to the study acknowledges that Lewin has the ability to model those expenses but was instructed by the Alzheimer’s Association to exclude them.

The association is correct that there is no way to predict what some future drug or other therapy could cost. But that treatment will surely not be free, as the report implies.

For a sense of how much, here’s some very rough math:

The five branded Alzheimer’s drugs currently approved by the FDA cost roughly $2,000-$5,000-a-year—even though none significantly slow cognitive decline. Assume that four million people take the association’s hypothetical drug from 2025 to 2035. At $4,000-per-person, that’s $16 billion annually, which would wipe out one-sixth of the group’s projected cost savings from 2026-2035. The actual drug costs could be more or less, of course, but they won’t be zero.

Still, that’s just money. Such a treatment, if it worked, would also improve the lives of millions of people and their families.

Except the Alzheimer’s Assn. study may overstate the number of people who could benefit from an Alzheimer’s treatment. That’s because perhaps only half of all people with dementia have Alzheimer’s (though many incorrectly think they do). And a treatment for Alzheimer’s likely would not benefit those whose memory loss is caused by strokes or other diseases or reduce the costs of their care.

Finally, keep in mind that the study is not an estimate of the cost of dementia care. Rather, it is a projection of all medical and long-term care costs for people with memory loss, nearly all of whom have other chronic conditions as well. For instance, for a woman with dementia and heart disease, Medicare will pay vastly more to treat her cardiac condition than her dementia. Even if her dementia is suppressed, Medicare will still have to pay for that cardiac care.

All of us hope that researchers find cures for dementia. But instead of releasing reports that exaggerate cost savings in an effort to boost government funding for drug therapies, I wish the Alzheimer’s Assn. and groups like it would focus more energy on supporting those who already have these conditions and their families.

Better care could reduce hospitalizations and vastly improve the quality of life of those with memory loss. And, by the way, it too would save money.