Type 2 diabetes and depression, separately, are each a factor that increases the risk of death in heart disease patients.

When combined -type 2 diabetes and depression - pose more deadly threat to heart disease patients: those with both type 2 diabetes and symptoms of depression were more likely to die than heart patients without those conditions.

Such were the findings of Duke University Medical Center psychologists after analysis of more than 900 patients with established coronary artery disease.

According to Duke researcher Anastasia Georgiades, Ph.D.:

"We found a trend showing that the probability of death increases as the level of depression increases in diabetic patients with coronary artery disease. Our data appear to show an important interaction between type 2 diabetes and depression, meaning that physicians should closely monitor their heart patients who have both of these disorders.

There is some sort of synergistic effect between type 2 diabetes and depression that we don't fully understand. In our analysis, we controlled for factors that could influence mortality, such as heart disease severity and age. For whatever reasons, these patients were still at higher risk of dying, and future research will aim to investigate the mechanisms for this association."

While the mechanisms of this association are still unknown, heart doctors should already closely monitor their patients exhibiting symptoms of both diabetes and depression.

Find more details from the full report.