Anti-dementia drugs increase lifespan for Alzheimer’s patients who take them

Persistent use of anti-dementia drugs during the course of Alzheimer’s disease appears to increase life expectancy, said researchers at Baylor College of Medicine in Houston at a presentation at the Alzheimer’s Association International Conference on Alzheimer’s Disease 2008 in Chicago.

"The life span of those with Alzheimer’s is known to be shorter than that of cognitively healthy people," said Dr. Susan Rountree, assistant professor of neurology at BCM and lead author of the study. "Our findings suggest that those who took anti-dementia drugs more persistently, or longer time intervals, lived longer than those who took the medications for shorter time periods."

Additional 3.12 years

The study followed 641 people suffering from Alzheimer’s disease between 1989 and 2005. All were on one or more commercially available anti-dementia drugs for varying amounts of time during the course of their illness. The drugs included donepezil, galantamine, rivastigmine, tacrine or memantine.

Researchers gave each subject a "persistency" score derived by dividing the total years that they took the medication by the total years that they had symptoms of the disease. They used these results to divide the patients into four quartiles, lowest to highest.

"We did take into account a variety of factors that influence life expectancy such as age and other diseases," Rountree said.

Those in the first quartile, the lowest persistency group, were 2.4 times more likely to die than those in the fourth quartile, or highest persistency group. Those within the second and third quartiles had an increased risk of death of 2.2 times and 1.5 times respectively, compared to those with the highest score. Those who had the higher scores lived, on average, 3.12 years longer than those with the lower scores.

Creating a Model

"While we have known that anti-dementia drugs help with symptoms of Alzheimer’s, we don’t have an accurate model as to how they affect life expectancy," said Dr. Rachelle Doody, professor of neurology and director of the Alzheimer’s Disease and Memory Disorders Center at BCM. "Our goal is to create a model of what a patient can expect."

Rountree said, "This model will then help assess the need for future health care resources and help families plan care for their loved ones."

(Source: Baylor College of Medicine: August 2008)