Anti-depressant use associated with increased risk for heart patients

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Public release date: 4-Mar-2006

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Duke University Medical Center

Anti-depressant use associated with increased risk for heart patients

DURHAM, N.C. –In a surprising finding, patients with coronary artery

disease who take commonly used antidepressant drugs may be at

significantly higher risk of death, Duke University Medical Center

researchers have found.

Even after controlling for such factors as age, degree of heart

disease and severity of depression, the researchers found that heart

patients taking antidepressant medications had a 55 percent higher

risk of dying. Previously, Duke researchers reported that the

presence of depression is an important risk factor for heart

patients. This new finding of the risk from anti-depressants raises

issues about the optimal way to treat depression in cardiac patients,

the researchers said.

According to Duke team leader Lana Watkins, Ph.D., the researchers

believe their findings add further support for the potential role oft

non-pharmocological approaches to treating depression, such as

exercise, in reducing the risk of death in depressed heart patients.

She said that physicians caring for heart patients who are taking

antidepressants should monitor patients closely.

Watkins added that the design of the study prevents definitive

conclusions regarding the effects of antidepressant drugs. In the

current observational study, patients were not randomized to receive

an antidepressant or a placebo drug, therefore characteristics of the

patients, such as more likelihood for their depression or their

medical condition to worsen, may be responsible for the effects, she

said.

Randomized placebo-controlled trials are needed to not only replicate

the Duke findings, but to better understand whether antidepressant

use is identifying patients likely to have more severe or worsening

depression or worsening medical disease during the follow-up period,

Watkins added.

" This finding that antidepressant use was an independent risk factor

for mortality in patients with coronary artery disease was quite

unexpected, " said Watkins, who presented the results of the Duke

study March 4, 2006, at the annual meeting of the American

Psychosomatic Society in Denver. The research was supported by the

National Heart, Lung, and Blood Institute.

" We were surprised since antidepressants, particularly the newer

class of antidepressants known as selective serotonin reuptake

inhibitors (SSRI), have been generally considered safe, " Watkins

said. " However, even after taking into account many patient

variables, as well as the type of antidepressant, the risk still

remained. So there is something important going on here that we don't

fully understand. "

During the past decade, cardiologists and physicians have gained a

greater appreciation that depression should be considered as an

important risk factor for patients with coronary artery disease, said

the researchers. For this reason, they have increasingly prescribed

antidepressants for these patients; however, this increase in use has

not been accompanied by conclusive scientific data on the effects of

antidepressants – especially SSRIs – on mortality.

For her study, Watkins prospectively analyzed the clinical data of

921 Duke University Hospital patients receiving a cardiac angiography

procedure to determine the extent of blockage in their coronary

arteries. Of the total number of patients, just under one in five

(19.4 percent) were taking an antidepressant; with SSRIs being taken

by 66 percent of those patients.

During their hospitalization, patients were given the Beck Depression

Inventory (BDI), a commonly used depression screening test. In

general, patients with a BDI score of 10 or higher are considered

depressed. In the Duke study, those patients who were not taking

antidepressants had an average BDI score of 7, while those on

antidepressants had an average score of 11, a statistically

significant difference.

The patients were followed over an average of three years, and during

that time 21.4 percent of the patients who were taking

antidepressants had died, compared to 12.5 percent for those not on

antidepressants.

After adjusting for such factors as age, gender, heart pumping

strength, smoking history, degree of other illnesses, heart

procedures, BDI score and education, the researchers found that

patients taking antidepressants had a 55 percent higher risk of

dying. The difference between SSRI and non-SSRI use – 61 percent vs.

49 percent – was not statistically significant.

Watkins said the future studies are needed to uncover the reasons

responsible for depression's negative effect on mortality. Also, she

said, researchers do not fully understand the physiological effects

of SSRIs on patients with coronary artery disease.

While physicians do not know why there appears to be a link between

depression and increased risk of mortality, there are a number of

theories, said Watkins. Depression has been linked to supression of

the immune system, as well as alteration of the aggregation

properties of blood platelets. It has also been linked to other such

cardiovascular risk factors as insulin resistance, hypertension,

obesity, increased cigarette smoking, alcohol abuse and physical

inactivity, she noted.

In April, Duke investigators will begin enrolling depressed patients

in a randomized trial testing the abilities of exercise and SSRIs to

impact such physiological markers of coronary artery disease as

platelet aggregation, heart rate variability and baroreflex

sensitivity, or the ability of blood vessel walls to respond

appropriately to changes in blood pressure.

Other Duke colleagues on the study included Blumenthal, Ph.D.,

son, M.D., McCants, O'Connor, M.D.

and Sketch, M.D.

http://www.eurekalert.org/pub_releases/2006-03/dumc-aua022806.php