October 10 (HealthDay News) -- In a group of Medicare beneficiaries who have diabetes, being depressed was associated with a higher death rate, according to a new study.

Publishing in the October issue of the Journal of General Internal Medicine, researchers from the University of Washington tracked 10,704 Medicare beneficiaries (average age of 75.6 years) who had diabetes and were enrolled in a disease management program in Florida. The participants' depression status was assessed by physician diagnosis, patient reports of antidepressant use, and answers to a brief screening test.

The researchers followed the participants for two years and recorded any deaths and causes of death that took place during that time.

The participants who had both diabetes and depression had an approximately 36 percent to 38 percent increased risk of dying from any cause. A total of 12.1 percent of these participants died during the study, compared with 10.4 percent of the participants without depression.

Participants who were treated with antidepressant medications in the year prior to the study had a 24 percent increased risk of death, compared to the participants who were not depressed. The study's authors suspect that the participants treated with antidepressants may have had more severe depression than other mildly depressed participants.

There was no difference in the incidence of cardiovascular or cerebrovascular events between the participants who took antidepressants and those who were not depressed.

"Rates of mortality from vascular disease may be decreasing in recent years among patients with diabetes due to more aggressive treatment of high blood pressure, cholesterol, and glucose levels, as well as widespread use of preventative medications such as aspirin and beta blockers," the researchers surmised.

The study's authors said there were several reasons why depression was associated with increased risk of death among the participants in their study.

First, depression has been associated with poor self-care and increased risk of poor health habits such as smoking and overeating. And, depression has been linked with nervous system disorders, endocrine system disorders, and inflammatory markers.

The authors noted that their study has certain limitations. The participants were selected from only one area of the United States, and the follow-up period was relatively short. And the study did not collect information on education, income, weight, smoking habits, physical activity, or compliance in taking medications.

SOURCE: University of Washington Health Sciences and UW Medicine, news release, Sept. 30, 2008