NEW YORK (Reuters Health) - Anxiety appears to increase the risk of heart attacks and death in patients who have coronary artery disease, researchers from the United States report.

Coronary artery disease is caused by plaque build-up on the inside walls of the arteries that supply blood and oxygen to the heart, causing them to harden and narrow. This can lead to heart attack, angina (chest pain) and other serious complications.

A number of studies have looked at the toll that mental stress takes on cardiac health, but most have focused on depression, not anxiety. The few studies that have examined the role that anxiety might play in heart disease have usually measured anxiety only once, not over the course of time, according to a report in the Journal of the American College of Cardiology.

This study involved 516 patients with heart disease who completed a standard anxiety questionnaire annually for an average of 3.4 years. The study group was 82 percent male with an average age of 68 years.

A total of 44 nonfatal heart attacks and 19 deaths occurred during the study period, Dr. Charles M. Blatt, from Harvard Medical School in Boston, and colleagues found.

A high cumulative anxiety score was associated with an elevated risk of both heart attack and death from any cause, whereas the initial anxiety score was not. Subjects with average anxiety scores in the highest 25 percent were nearly twice as likely to die of a heart attack or death from any cause compared with those with scores in the lowest 25 percent.

Upon further analysis of the data, in which the researchers factored in the effects of high blood pressure, diabetes, and other known cardiovascular risk factors, each unit increase in the overall anxiety score increased the odds of nonfatal heart attack or death by 6 percent.

Initial anxiety scores failed to predict negative patient outcomes, "suggesting that assessing anxiety regularly over the long-term is necessary," the authors conclude. Randomly assigned clinical studies are now needed to see if treatment to reduce anxiety can improve the outcome of patients with coronary artery disease.

SOURCE: Journal of the American College of Cardiology, May 22, 2007.

REUTERS