Depression in patients with type 2 diabetes was associated with greater cognitive decline in a study of almost 3,000 individuals who participated in a clinical trial, according to a report published by JAMA Psychiatry, a JAMA Network publication.
Depression and diabetes are among the most common illnesses in older primary care populations. Up to 20 percent of adult patients with type 2 diabetes meet the criteria for major depression. Both depression and diabetes appear to be associated with an increased risk for dementia, Mark D. Sullivan, M.D., Ph.D., of the University of Washington, Seattle, and colleagues write in the study background.
“Depression has been identified as a risk factor for dementia among patients with type 2 diabetes mellitus but the cognitive domains and patient groups most affected have not been identified,” the study notes.
The study included 2,977 patients with type 2 diabetes at high risk for cardiovascular disease who were participants in the Action to Control Cardiovascular Risk in Diabetes-Memory in Diabetes (ACCORD-MIND) trial. Researchers used tests to gauge cognition and a questionnaire to assess depression.
According to the results, patients with scores indicative of depression showed greater cognitive decline during the 40-month follow-up on all tests. The effect of depression on risk of cognitive decline did not differ according to previous cardiovascular disease; baseline cognition or age; or intensive vs. standard glucose-lowering treatment, blood pressure treatment, lipid treatment or insulin treatment, the results also indicate.
“In summary, this epidemiological analysis of the effect of depression on risk for cognitive decline among participants in the ACCORD-MIND study showed that depression is associated with cognitive decline in all domains assessed and that this effect does not differ in important clinical subgroups. This suggests that a potentially reversible factor may be promoting general cognitive decline in the broad population of patients with type 2 diabetes. Since dementia is one of the fastest growing and most dreaded complications of diabetes, our findings may be important for public health,” the study concludes.
JAMA Psychiatry. Published online August 14, 2013. doi:10.1001/jamapsychiatry.2013.1965.