People living with diabetes who also have untreated depression are at increased risk of death, according to a new evidence review in an upcoming issue of General Hospital Psychiatry.

More than 42,000 patients with type 1 or type 2 diabetes and depression were analyzed in the review. The reviewers discovered that depression was associated with a 1.5 fold increase in the risk of dying. In four of the studies reviewed, co-morbid depression was linked to about a 20 percent higher risk of cardiovascular death for people with diabetes.

"Depression consistently increased the risk of mortality across virtually all studies," said Mijung Park, Ph.D., lead author and assistant professor at the University of Pittsburgh School of Nursing. "We can now postulate that the harmful effect of depression is universal to individuals with diabetes."

Todd Brown, M.D., associate professor of medicine and epidemiology at Johns Hopkins University in Baltimore, said it is very common to see a patient go into a downward spiral when obesity-related co-morbidities, such as diabetes, high blood pressure, obesity and depression converge.

"Obesity can lead to worsening metabolic status that can lead to hopelessness and decreased physical activity, which in turns worsens obesity, and the cycle continues," he explained.

The encouraging news is that depression is a highly treatable condition, said Park. Because depression can make diabetes self-care more difficult and lessen quality of life, she suggested that depression treatment should be included in overall diabetes care strategies.