One hundred years ago, the eminent German physician, Emil Kraepelin, published the eighth edition of his very successful textbook on psychiatry. It wasn't terribly different from the preceding version, but one small change would prove to have enduring consequences. Several neurologists and psychiatrists had described a disorder that looked very much like the dementia associated with old age but which afflicted people as young as 50. Kraepelin gave the disease a name. He called it "Alzheimer's disease," based on a case report that the neuropathologist Alois Alzheimer had presented in 1906. The name stuck although "Alzheimer's disease," was ultimately found to be indistinguishable from age-related dementia. What have we learned about the disease in the ensuing 100 years? The Alzheimer's Society's new report, Alzheimer's Facts and Figures 2010 gives us a snapshot of the disease as we know it today.
For 100 years there has been debate about the cause of dementia. Is it caused by plaques and tangles, the abnormal material that Alois Alzheimer observed under the microscope when he examined the brain of his patient, Frau Auguste D, after her death? Or is it a vascular condition, due to hardening of the arteries? For the last several decades, physicians have been confident that there are several distinct forms of dementia, with Alzheimer's disease and vascular or multi-infarct dementia discrete entities. But now the lines are blurring: a new autopsy study suggests that many cases of dementia are due to a mixture of several problems. By examining the brains of older individuals who had clinical evidence of Alzheimer's disease during life, scientists found that less than half of them had Alzheimer's disease alone. Fully one-third had infarcts (strokes) as well as Alzheimer's changes in their brains. About 15% had changes of Parkinson's disease in addition to Alzheimer's. These findings are not merely of academic interest: if it takes several distinct processes occurring simultaneously to produce dementia, there are potential therapeutic implications. Perhaps it will sufficient to intervene in just one of the processes-or maybe it will be necessary to strike all the contributors to the disease at once.
When Alzheimer described his patient, Frau Auguste D, a woman who first presented at age 51 with memory loss, paranoia, and the inability to care for herself, dementia was relatively rare. Most cases of dementia, after all, arise in people over age 65 and life expectancy in Germany in the early 20th century was only 60 years. The latest prevalence data show that today 5.3 million Americans have Alzheimer's disease or some other form of dementia, 5.1 million of whom are 65 years of age or older. The disease disproportionately affects women-which is partly but not entirely due to the fact that women live longer than men. A total of 10% of men and 16% of women over age 70 have dementia.
What Kraepelin and Alzheimer did not fully appreciate but what we know now is that dementia is a terminal illness: it is the 5th leading cause of death in people over age 65. But most people with dementia also have other chronic diseases, which makes sorting out what actually causes death is tricky: fully 60% of Medicare patients with dementia have high blood pressure, 26% have coronary artery disease, 23% have diabetes, and 25% show the residual effects of strokes.
Caring for individuals with dementia was sometimes a challenge even in Alzheimer's day-Frau D. had to be institutionalized because her behavior was so difficult to manage. The situation today is orders of magnitude more problematic. The number of people with dementia is growing dramatically, but the numbers of trained geriatric professionals (physicians, nurses, social workers) is not. Right now there are a paltry 7128 physicians who are board certified in geriatrics, with the projected need by 2030 estimated at 36,000 and no evidence that more doctors are going into the field. Even more worrisome is the lack of personal caregivers. Currently most of the direct care for people with dementia is provided by family and friends: 11 million unpaid caregivers provide a stunning 12.5 billion hours of care annually, or about 22 hours/week. As the population with dementia increases, it is far from clear how we will provide adequate professional and non-professional care.
In 1910, medical technology was essentially nonexistent. In 2010, it is widespread, especially in older people and even more so in older people with dementia. Medicare beneficiaries with dementia are 3 times more likely than their non-demented counterparts to be hospitalized. Looked at differently, at any point in time about one-fourth of all hospitalized patients over age 65 have dementia. Reflecting this trend, Medicare spends $15,145/year for each person with dementia compared to $5272/year for each person without dementia-and these figures do not include long term nursing home care, which is not covered by Medicare. What these numbers mean is that people with dementia receive is the same high tech, life-prolonging treatment that non-demented patients receive-multiplied by three both because they tend to have other chronic diseases and because they cannot articulate what exactly is bothering them, resulting int their being subjected to even more tests than other people. At first glance this might seem like a good thing, indicating that patients with dementia are not discriminated against. But instituting aggressive, life-prolonging therapy in people who have a terminal disease is of questionable benefit, particularly when it both causes suffering (people with dementia do not understand why they are receiving painful or frightening procedures) and is hugely expensive.
Kraepelin and Alzheimer lived in an ethnically and racially homogeneous society. Contemporary America is ethnically diverse and racial disparities in medical care are widespread. What is particularly striking is new evidence that older African Americans have twice the risk of developing dementia as do their white counterparts. The Washington Heights-Inwood Columbia Aging Program found that among people 85 years of age or older, the prevalence of dementia is 30.2% in whites, 58.6% in blacks, and 62.9% in Hispanics. The high rate of hypertension, diabetes, stroke, and coronary disease in African Americans and Hispanics may be responsible for the disparities. There is some hope that prevention of these conditions will ultimately be found to prevent dementia, although a recent NIH state-of-the-science conference concluded that "there is currently no evidence considered to be of even moderate scientific quality supporting the association of any modifiable factor...with reduced risk of Alzheimer's disease."
The centennial of Kraepelin's momentous naming decision is passing almost unnoticed. It should stimulate renewed dedication to addressing the challenges of caring for the growing numbers of patients and families devastated by Alzheimer's disease.