Analysis of several clinical factors predicts long-term survival of patients newly diagnosed with Alzheimer's disease, according to an article in the April 6th issue of the Annals of Internal Medicine.

The American research group found that, overall, people with Alzheimer's disease survived roughly 50 percent as long as their unaffected age peers. Affected women tended to live longer than men, surviving roughly 6 years after diagnosis compared with 4 years; the gender difference narrowed with increasing age. Age at diagnosis was itself a predictor. Patients diagnosed in their 70s had longer survival times than people diagnosed at age 85 years or older.

"This finding moves us toward a more precise vision of the course that Alzheimer's may take in people with certain clinical characteristics," said Eric B. Larson, MD, lead author of the study. "For doctors, this provides very useful data for gauging the prognosis of an Alzheimer's disease patient. For patients and their caregivers, as difficult as this may be to hear, it can help in making appropriate plans for the future."

In the current study, investigators followed 521 community-dwelling men and women aged 60 years or older who had been recently diagnosed with Alzheimer's disease. They were recruited from a database of 23,000 people listed in an Alzheimer's Disease Patient Registry in a single urban area. The average follow-up period was about 5 years, with an approximate range from 2.5 months to 14 years.

At enrollment into the study, each patient was evaluated for cognitive and memory problems and examined for other conditions including heart disease, heart failure, diabetes, stroke, depression, and urinary incontinence. They were also assessed for a history of agitation, wandering, paranoia, falls and walking difficulties. Survival was measured from the time of initial diagnosis until death or when the study ended in 2001.

When compared to the life expectancy of the general population, overall survival was lower for patients across all age groups. For instance, median survival was 8 years for women aged 70 years at diagnosis, roughly half the life expectancy of similarly aged American women who do not have the disease. Similar trends were found among 70-year-old men with Alzheimer's disease, who had a median survival time of 4.4 years compared with 9.3 years for the U.S. population.

Survival was poorest among those aged 85 and older who wandered, had walking problems, and had histories of diabetes and congestive heart failure. However, the difference in life expectancy between patients and the general population progressively diminished with age. At 85 years, for example, median life expectancy for women diagnosed with Alzheimer's disease was 3.9 years compared with about 6 years for unaffected women. Similarly, 85-year-old men with newly diagnosed Alzheimer's disease had a median life expectancy of 3.3 years compared with 4.7 years for men of the same age who didn't have the disease.

Poor scores on initial tests of memory and cognitive performance predicted shorter survival time after diagnosis. In fact, a 5-point drop in a key test, the Mini-Mental State Exam, during the first year following diagnosis, predicted up to a 66 percent increase in risk of death after that initial year. Walking problems, congestive heart failure, and a history of falls, diabetes, and ischemic heart disease were other important predictors of reduced life expectancy after diagnosis.

"This study suggests that several critical factors can be evaluated to help answer some of the important questions posed by Alzheimer's disease patients and their families," said Neil Buckholtz, PhD, of the National Institutes of Health. "These conversations are never easy. But these findings could help clarify what patients and families can expect. And ultimately, families who have more precise information on the likely course of the disease should be better prepared to deal with it as it progresses."