Can cognitive impairment have an impact on life expectancy similar to chronic conditions such as diabetes or chronic heart failure? A new study spanning 13 years says yes and explains why in the new issue of Annals of Internal Medicine this week.

Cognitive impairment that develops in childhood or adolescence can result from many conditions. Examples include side effects of cancer therapy, malnutrition, heavy metal poisoning, autism (abnormal development of communication and social skills), metabolic conditions, and systemic lupus erythematosus (disorder in which the body attacks its own healthy cells and tissues).

With age, other conditions such as stroke, dementia, delirium, brain tumors, chronic alcohol use or abuse, substance abuse, some vitamin deficiencies, and some chronic diseases may cause cognitive impairment. Head injury and infection of the brain or of the covering of the brain and spinal cord (meninges) can cause cognitive impairment at any age.

For the purpose of this long term study, the team followed 3,957 patients. At screening, 3,157 had no cognitive impairment, 533 had mild impairment, and 267 had moderate to severe impairment.

During follow-up, 57% of patients with no impairment had died, compared with 68% of those with mild impairment and 79% of those with moderate to severe impairment. Median survival time was 138 months for patients with no impairment, 106 months for those with mild impairment, and 63 months for those with moderate to severe impairment.

Study participants were screened for cognitive impairment using a ten question mental status questionnaire. On the basis of the number of errors patients made on this test, they were categorized as having no, mild, or moderate to severe cognitive impairment. The Regenstrief Medical Record System was used to obtain data on the patients’ medical conditions, results of lab tests and other relevant information.

Regenstrief investigator Greg A. Sachs, M.D., professor of medicine at the Indiana University School of Medicine, where he is the division chief of general internal medicine and geriatrics explains:

“Previous studies have associated cognitive impairment with an increased risk for death, but most of this work focused on patients with Alzheimer disease and subjects in research centers. The patients in our study better reflect the general public, displaying no indications of disease or mild, moderate or severe cognitive impairment. We found that even mild cognitive impairment, as determined by a simple screening tool in a primary care physician’s office, has a strong impact on how long individuals survive on the same order as other chronic diseases.”

Reduced life expectancy in patients with cognitive impairment should be factored into medical decisions, such as advance care planning, cancer screening and prescribing of medications, especially in patients with severe impairment.

Approximately 4 million to 5 million people in the United States have dementia, and the number of individuals affected is significantly higher if individuals with milder forms of cognitive impairment are included. The prevalence of cognitive impairment at all stages is expected to increase as the population ages.

Given that the magnitude of the risk of mild and moderate to severe cognitive impairment is similar to that of many life-limiting diseases, as well as the ease of indentifying cognitive impairment by using a short screening tool, recognition of cognitive impairment in primary care practices should be given a higher priority according to researchers.

Written by Sy Kraft