Having both type 2 diabetes and depression puts patients with coronary artery disease at greater risk of death over a 4.5-year period than does either condition alone.
That finding emerged from a study presented at the American Psychosomatic Society meeting in Budapest, Hungary.
The more severe the depressive symptoms were in those patients with both coronary artery disease and diabetes, the greater their risk of death in the follow-up period.
Having high scores on the Beck Depression Inventory increased the risk of dying during the follow-up period by 20%–30%, compared with patients with similar depression scores but without type 2 diabetes, according to investigators from Duke University, Durham, N.C.
These findings suggest that physicians should screen for and treat depression in patients with diabetes and heart disease.
“There is some sort of synergistic effect between type 2 diabetes and depression that we don't fully understand,” lead researcher Anastasia Georgiades, Ph.D., said in a written statement. “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.”
The study compared 325 patients with type 2 diabetes and 582 patients without the disease during hospitalization for a coronary angiography. Their depression symptoms were rated using the Beck Depression Inventory (BDI). Approximately 25% scored at least 10 on the BDI, indicating depression, Lana Watkins, Ph.D., an investigator in the study, noted in an interview.
During the follow-up period of 4.5 years (median, 3 years), the researchers documented 135 deaths among the study participants. Among the depressed patients, 19% died, compared with 12% of those patients without depression, Dr. Watkins said.
The researchers found statistically significant associations between depressive symptoms and increased mortality and, separately, diabetes and increased mortality. The highest mortality was among patients with both diabetes and elevated BDI scores. The researchers did not publicize hazard ratios, however, because they said those statistics would overestimate the risk and create anxiety among patients.
“Patients with type 2 diabetes typically have an extensive self-care regimen involving special diet, medications, exercise, and numerous appointments with their doctor,” Dr. Georgiades said in the statement. “It may be that such patients who are depressed might not be as motivated to carry out all these activities, thereby putting them at higher risk.”
Physicians treating patients with heart disease and diabetes need to screen them for depression and treat as needed.
“Regular exercise has been shown to improve depression, too, so that might be an option,” Dr. Watkins noted in an interview. “This could potentially improve depression and diabetes, and might be a good first choice for diabetics who would prefer not having to take additional medications.”