A new study by researchers at the Intermountain Medical Center Heart Institute has found that screening for and treating depression could help to reduce the risk of heart disease in patients with moderate to severe depression.
Researchers at the Intermountain Medical Center Heart Institute, the flagship facility for the Intermountain Healthcare system based in Salt Lake City, analyzed the health records and rates of death, coronary artery disease and stroke of more than 26,000 patients treated by Intermountain over a three-year period.
This is the first study to assess the relative effects of the simultaneous use of antidepressants and cholesterol-lowering drugs among patients with varying levels of depressive symptoms.
Patients completed a nine-question depression screening questionnaire, which assessed such factors as mood, sleep and appetite, to determine their level of depressive symptoms. Based on the questionnaires, researchers identified 5,311 patients as having moderate to severe depression and 21,517 patients as having no to mild depression.
The study, presented March 15, 2015 at the American College of Cardiology's 64th Annual Scientific Session in San Diego, found patients with moderate to severe depression who took antidepressants alone had a lower risk of death, coronary artery disease and stroke than patients with moderate to severe depression who did not take antidepressant or statin medications.
Researchers found that taking statins alone or in combination with antidepressants was not associated with a significant risk reduction in this group of patients.
Although the study does not evaluate how antidepressants decreased the risk of cardiovascular disease, the study's lead author Heidi May, PhD, MSPH, a cardiovascular epidemiologist at the Intermountain Medical Center Heart Institute, believes the link could have some relation to behavioral changes.
"Antidepressants might have relevant physiological benefits, but I also think the behavioral changes that improve a person's mood can also improve cardiovascular health," Dr. May said. "This study demonstrates the importance of evaluating patients for depression, not only in terms of improving their mood, but reducing their risk for heart disease."
"Antidepressants were not associated with a reduced cardiovascular risk in people with little or no depression, but in moderately to severely depressed people, antidepressants were shown to significantly improve cardiovascular outcomes," she added.
Patients with moderate to severe depression who were taking antidepressants alone had a 53 percent lower risk of dying, developing coronary artery disease or having a stroke during the three-year follow-up period as compared to patients with moderate to severe depression who were not taking antidepressants or statins.
Moderately to severely depressed patients taking antidepressants alone appeared to also fare better than those taking statins alone or a combination of statins and antidepressants, although these relationships were not directly analyzed.
"We thought we'd see an additive effect--that taking both medications would lower the risk more than either drug alone--but we found that in the more depressed people, the antidepressant really was what made the biggest difference," Dr. May said. "Focus is usually placed more on traditional cardiovascular risk factors and unfortunately, depression is often overlooked. This study adds to the evidence that, when used properly, antidepressants can improve cardiovascular outcomes among those with depressive symptoms."
The researchers excluded from the analysis patients with known cardiovascular disease such as heart failure, coronary artery disease, or a previous heart attack or stroke. They also excluded those who were already taking antidepressants when they completed the questionnaire.
Depression is a known risk factor for cardiovascular disease. An estimated one in 10 adults suffers from depression, according to the Centers for Disease Control and Prevention. Patients with depression have a two- to four-times greater risk of developing cardiovascular disease compared to those without depression.
The analysis accounted for standard cardiovascular risk factors such as diabetes, smoking and hypertension. However, because the study only included information that was available in patients' health records, the researchers were unable to account for other factors such as level of physical activity, changes in habits or non-drug mental health treatment such as psychotherapy.
Dr. May said future studies could help to further refine understanding of the relationships between depression, antidepressants and cardiovascular health.