Study: Dementia deadlier than first thought

(CNN) -- Nearly four million Americans suffer from Alzheimer's disease, a mind-robbing condition that can exact a terrible psychological and financial toll on victims and their families. But few people, including many physicians, consider the disease to be deadly.

But for older patients at least, an Alzheimer's diagnosis can be as devastating and potentially deadly as heart disease or cancer, according to a study published in the New England Journal of Medicine (NEJM).

The prevalence of Alzheimer's disease is projected to quadruple nationwide in the next 50 years, which means 1 in every 45 Americans will be afflicted with the degenerative condition, NEJM reported. The dramatic increase is primarily due to an aging population.

The effect an Alzheimer's diagnosis can have on families is enormous.

Gary Coleman has watched his mother, Esther, who is 86, struggle with Alzheimer's disease for about 10 years.

"It's never been presented to me as life-threatening or anything that would have to do with her life expectancy or her quality of life," Coleman said of his mother's diagnosis.

But The NEJM study found that patients 84 years of age and older will survive, on average, only three years after they first see a physician for symptoms that include memory loss.

That makes the disease as deadly as other major killers, according to Dr. Claudia Kawas of the University of California at Irvine, in an accompanying editorial.

"It's malignant and shortens the time you stay alive. Having said that," she added, "how much it shortens is determined by how old you are."

Most people don't think of dementia as a deadly condition, but "as time goes on they (patients) have difficulty swallowing, they may have difficulties walking," wrote Kawas, "and they become more susceptible to malnutrition and to infections."

"People with Alzheimer's disease, as time goes on, look very sick and they die just like people with cancer or heart disease or other chronic problems that are our leading killers," explained Kawas.

Life expectancy estimates, however, are just that -- estimates.

Atlanta-based geriatrician Dr. Jeff Lesesne advised caution when trying to predict how long a patient may survive after diagnosis.

"The course of events can be variable in the patient, and so it's hard to predict exactly what someone is going to experience," he said.

Alzheimer's disease attacks the nerve cells of the brain and impairs a person's memory, coordination and control over emotions. In its last stages, the disease robs its victims of all mental functioning.

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Alzheimer's Association
Alzheimer's Disease Education and Referral Center
Centers for Disease Control and Prevention

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