Patients with both anxiety and depression have triple the risk of dying, researchers said.
"Many studies have linked depression to an increased risk of death in heart disease patients," said Lana Watkins, Ph.D., lead author of the study and an associate professor in Psychiatry and Behavioral Sciences at Duke University Medical Center in Durham, N.C. "However, anxiety hasn't received as much attention."
Studies show that depression is about three times more common in heart attack patients. The American Heart Association recommends that heart patients be screened for depression and treated if necessary.
Depressed heart disease patients often also have anxiety, suggesting it may underlie the risk previously attributed solely to depression, Watkins said. "It's now time for anxiety to be considered as important as depression, and for it to be examined carefully."
In the study, 934 heart disease patients, average age 62, completed a questionnaire measuring their level of anxiety and depression immediately before or after a cardiac catheterization procedure at Duke University Medical Center. Patients had anxiety if they scored 8 or higher on a scale composed of seven common characteristics of anxiety, with each item rated from 0 to 3 (range of possible scores: 0-21). Depression was measured using a similar scale composed of seven symptoms of depression.
Researchers, after accounting for age, congestive heart failure, kidney disease and other factors that affect death risk, found:
- 90 of the 934 patients experienced anxiety only, 65 experienced depression only and 99 suffered anxiety and depression.
- Among 133 patients who died during three years of follow-up, 55 had anxiety, depression or both. The majority of deaths (93 of 133) were heart-related.
Anxiety and depression each influence risk of death in unique ways. Anxiety, for example, increases activity of the sympathetic (adrenaline-producing) nervous system that controls blood pressure.
"People who worry a lot are more likely to have difficulty sleeping and to develop high blood pressure," Watkins said.
The link between depression and mortality is more related to behavioral risk factors, she said. "Depression results in lack of adherence to medical advice and treatments, along with behaviors like smoking and being sedentary."
Future studies should test strategies to manage anxiety alone and with depression in heart disease patients, Watkins said.
"Anxiety reducing medications combined with stress management could improve outcome for patients with just anxiety, whereas patients with anxiety and depression may need a stronger intervention involving more frequent outpatient monitoring and incentives to improve adherence," she said.