Study questions accuracy of mortality statistics

December 10, 2008

Deaths due to dementia and Alzheimer's disease are underreported on death certificates, according to a study conducted by Hebrew SeniorLife's Institute for Aging Research (IFAR), raising concerns about the accuracy of mortality statistics based on these documents.

According to the National Center for Health Statistics (NCHS), which derives its data from death certificates, Alzheimer's disease, the most common form of dementia, is the fifth leading cause of death among Americans over age 65. Dementia is the loss of mental capacities—thinking, memory, reasoning and decision making, among others—that interferes with a person's daily functioning.

The IFAR researchers used data collected between 2003 and 2007 from the Choices, Attitudes, and Strategies for Care of Advanced Dementia at the End-of-Life, or CASCADE, study of 323 residents from 22 Boston-area nursing homes with advanced dementia. Of the 323 participants, 165 died during follow up. Thirty-seven percent of all decedents had no mention of dementia anywhere on their death certificates. Among the subset of 114 decedents diagnosed with Alzheimer's disease prior to death, documentation of dementia anywhere on their death certificate was none (33.3%), Alzheimer's disease (27.2%), dementia without further specification (37.7%), and vascular dementia (0.9%).

"Despite the terminal stage of dementia in our cohort," says lead author Susan L. Mitchell, M.D., M.P.H., a senior scientist at IFAR, "dementia was not recorded on 37 percent of death certificates. The absence of Alzheimer's disease on three-quarters of death certificates of decedents with this premortem diagnosis is a particular problem because, among the causes of dementia, NCHS ranks only Alzheimer's disease among its leading causes of death."

The study was published in the December 10 issue of the Journal of the American Medical Association.

Dr. Mitchell and her colleagues say an "appreciation that patients die from and with dementia is necessary to inform end-of-life decision making." They add that the underreporting of deaths from dementia may hamper the planning of much-needed health services for people dying from this condition.

Scientists at HSL's Institute for Aging Research conduct rigorous medical and social studies, leading the way in developing strategies for maximizing individuals' strength, vigor and physical well-being, as well as their cognitive and functional independence, in late life.

Source: Hebrew SeniorLife Institute for Aging Research