SUMMARIES FOR PATIENTS

Early Symptoms Help Predict Survival Time in Patients with Alzheimer's Disease

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The summary below is from the full report titled "Survival after Initial Diagnosis of Alzheimer Disease." It is in the 6 April 2004 issue of Annals of Internal Medicine (volume 240, pages 501-509). The authors are E.B. Larson, M.-F. Shadlen, L. Wang, W.C. McCormick, J.D. Bowen, L. Teri, and W.A. Kukull.

What is the problem and what is known about it so far?

Alzheimer's disease causes progressive loss of mental function and is a leading cause of death among older people. When doctors first diagnose Alzheimer's disease, patients and their families often want to know what to expect regarding symptoms and probable length of life. To date, few long-term studies have tried to relate patients' symptoms to length of survival in persons with recently diagnosed Alzheimer's disease.

Why did the researchers do this particular study?

To find out whether observations made during the first year of Alzheimer's disease could help predict how long patients would live.

Who was studied?

521 newly diagnosed patients who were accepted into an Alzheimer's Disease Patient Registry between 1987 and 1996.

What did the researchers do?

Each patient's age, sex, race, blood pressure, and education were recorded along with symptoms, such as depression, agitation, feelings that others wanted to harm him or her, wandering, unsteadiness in walking, tendency to fall down, and involuntary loss of urine. Loss of mental function was evaluated by using a standard test known as the Mini-Mental State Examination (MMSE). A doctor then examined the patient and recorded specific abnormalities of the brain and spinal cord. The researchers calculated the percentage of patients who died within a given period according to what symptoms they had at the beginning of the study. Because the researchers were also interested in evaluating whether rapidity of loss of mental function was important in determining survival time, they repeated the MMSE and calculated the change in MMSE score at the end of 1 year of observation.

What did the researchers find?

Survival in patients with Alzheimer's disease was significantly shorter than the average survival for the general population of the United States. The midpoint of survival for all patients with Alzheimer's disease was 4.2 years for men and 5.7 years for women, although younger patients tended to live longer and older patients had a shorter survival. In addition to advancing age, certain symptoms, such as unsteadiness in walking, falls, wandering behavior, and involuntary loss of urine, were associated with shorter survival. Lower MMSE score at the time of diagnosis as well as a decrease of 5 points or more during the first year of observation were associated with significantly decreased survival time. Certain abnormalities of brain and spinal cord function were also associated with shorter survival. The severity of Alzheimer's disease at the time of diagnosis was the strongest predictor of length of survival.

What were the limitations of this study?

Because patients were selected from a single health maintenance organization sample, the results may not be representative of all patients with Alzheimer's disease in the United States.

What are the implications of the study?

Certain characteristics observed during the first year after diagnosis of Alzheimer's disease can help predict length of survival.