April 5, 2004
A diagnosis of Alzheimer's is a devastating experience for persons with the disease and their loved ones. As memory and mental skills wane, afflicted persons can no longer care for themselves, and family members must assume an increasing burden of care. Many patients and their families wish to know how long someone diagnosed with Alzheimer's can be expected to live, and how long care will be needed. A new study out of the University of Washington in Seattle offers new clues about this important but difficult issue.
"We've always known that Alzheimer's disease shortens patients' lives, but there have been few long-term studies that relate patient age and symptoms to length of survival," said Eric B. Larson, M.D., M.P.H, a principal investigator for the study and director of the Center for Health Studies at Group Health Cooperative Center in Seattle.
This large and long-term study took a rigorous look at age at diagnosis, symptoms, severity of disease, and overall health. The researchers recruited 521 Seattle residents, aged 60 and older, who were recently diagnosed with Alzheimer's disease. Participants were tested regularly for an average of 5 years. Some were followed for as long as 14 years. They were given regular memory tests and also examined for other illnesses, such as heart disease, diabetes, strokes, and depression. They were also given questionnaires designed to detect troubling behaviors that may occur in people who have Alzheimer's, like wandering, paranoid feelings, falls, agitation, and trouble walking.
The researchers identified some general trends about Alzheimer's and life expectancy. It is important to remember, however, that survival times vary widely from person to person. There is no way to know for sure how long someone with Alzheimer's will continue their downward spiral. Some live only a few years after diagnosis, while others are still going strong after a decade. This study identified some general trends that may help people with Alzheimer's, their families, and their doctors plan for the future. Among the findings:
Women with Alzheimer's tend to live longer than men.
Overall, women who had Alzheimer's tended to live longer than men with the disease. Women survived an average of about 6 years after they were diagnosed, versus 4 years for men. However, there is considerable variation from person to person.
Alzheimer's cuts life expectancy.
Americans with Alzheimer's survived about half as long as those of similar age who did not have the disease. A woman who is diagnosed with Alzheimer's at age 70, for instance, would be expected to live on average for about 8 more years. The typical 70-year-old woman without the disease, on the other hand, would be expected to live another 16 years. The figures were smaller for American men, who tend to have shorter life expectancies in general: 4.4 years for a 70-year-old man diagnosed with Alzheimer's, versus 9.3 years for a man without the ailment.
The older the age at diagnosis, the shorter the life expectancy.
The older a man or woman was when they were told they have Alzheimer's, the less gap there was in life expectancy between men and women. At age 85, women diagnosed with Alzheimer's had a median life expectancy of 3.9 years, versus 6 years for women who didn't have the illness. Men newly diagnosed at age 85 had a life expectancy of 3.3 years, compared to 4.7 years for those without Alzheimer's.
The more severe the symptoms at the time of diagnosis, the shorter the survival.
Someone who has more severe symptoms when they are told they have Alzheimer's would not be expected to live as long as someone who has milder disease. Important predictors of diminished life expectancy include:
- Survival was poorest among those 85 and older who wandered, had trouble walking, or had histories of diabetes or congestive heart failure.
- Other health problems that tended to reduce life expectancy included having trouble walking or a history of falls. Those who had diabetes or heart problems (namely heart failure or a past heart attack) also tended to fare more poorly.
- Those who scored the worst on initial memory and thinking skills tests did not live as long. Those with a 5 point drop during the first year on one commonly used test, the Mini-Mental State Exam (MMSE), were especially likely to have diminished life expectancies.
In an editorial accompanying the article, Drs. Kenneth Covinsky and Kristine Yaffe of the San Francisco Veterans Affairs Medical Center and the University of California, San Francisco note that someone who receives a diagnosis of Alzheimer's through a specialized memory tests such as the MMSE is likely to have a considerably longer life expectancy than the people in this study. That's because these tests typically pick up cognitive problems long before a patient or family member comes in to their doctor with concerns. In other words, people whose first sign of Alzheimer's is a low score on the MMSE are likely to be in a very early stage of the disease and therefore may be expected to live longer.
A Chronic Illness Requiring Long-Term Planning
Alzheimer's disease is a chronic illness; its course may range from a few years up to 20 years. Symptoms are progressive, which means that each stage of the illness will require different levels of care. Moreover, each person is affected differently at each stage. In final stages, the person with Alzheimer's requires complete care, 24 hours a day, seven days a week. No single person can manage all this care all the time.
Although individuals vary widely in how they will fare over the long haul, this study offers important new clues about the long-term course of the illness. "Research that sheds light on the course of Alzheimer's disease is so important for physicians, patients, and families," said Neil Buckholtz, Ph.D., chief of the Dementia and Aging Branch at the National Institute on Aging, one of the sponsors of the study. "Having an idea of what to expect can hopefully be of some benefit in planning for what lies ahead."
Eric B. Larson, M.D., M.P.H., Marie-Florence Shadlen M.D, Li Wang, M.S., et al: "Survival after Initial Diagnosis of Alzheimer's Disease." Annals of Internal Medicine (April 6, 2004, Volume 140: pages 501-509).
Kenneth E. Covinsky, M.D., M.P.H., Kristine Yaffe, M.D.: "Dementia, Prognosis, and the Needs of Patients and Caregivers" (Editorial). Annals of Internal Medicine (April 6, 2004, Volume 140, Number 7, pages 573-574).
Group Health Cooperative and Center for Health Studies, Seattle, Washington.