More research urged on antidepressant heart riskMar 6, 2006 | www.NewScientist.com
Medical experts are calling for more research into how antidepressants affect people with coronary artery disease.
The call comes after a preliminary study of heart patients taking the drugs unexpectedly found the patients face a greater risk of death. But experts stress that depression itself is a risk factor for heart patients and say that doctors should not stop prescribing antidepressants to people who need them.
A class of antidepressants called selective serotonin-reuptake inhibitors (SSRIs) "are prescribed very often for depressed heart patients and are thought to be safe", says epidemiologist Amy Ferketich at the Ohio State University School of Public Health in the US. Her work has shown that depression appears to raise levels of inflammatory molecules in the body.
Other scientists have found that depression alters blood platelets, making the platelets stickier and perhaps more ready to form clumps. Scientists have also linked depression to other cardiovascular risk factors, such as obesity and increased cigarette smoking.
The result of the latest study was surprising because earlier work suggested antidepressants can actually lower the risk of death in heart patients. For example, a recent investigation of 1800 people with depression who had suffered a heart attack showed that those taking SSRIs had a 43% lower risk of death from all causes (Archives of General Psychiatry, vol 62, p792).
In the latest study, James Blumenthal of Duke University in Durham, North Carolina, US, and colleagues recruited more than 900 patients with coronary artery disease some of whom were not depressed and followed them for an average of three years. About one in five of the study group were taking an antidepressant, 66% of which were SSRIs.
They found the patients taking antidepressants faced a 55% greater risk of dying than those not on the drugs. “That’s enough to raise questions,” says Alexander Glassman of the New York State Psychiatric Institute, US, though he stresses that the study involves “tiny numbers” and larger follow-ups are necessary. Ferketich agrees: "It's intriguing and should definitely be followed up."
A further analysis of the Duke University data focussed exclusively on the depressed patients, whether they where taking antidepressants or not. This shows a less dramatic link between the use of the drugs and risk of death. Blumenthal suggests this may indicate that underlying depression itself could have predisposed the patients on the drugs to increased risk.
The researchers themselves note that the trial was not randomised or placebo-controlled. So while the findings suggest a link between antidepressants and increased risk in heart patients which should be investigated “it would be wrong to imply causality”, Blumenthal stresses.
He says that until more is known, doctors should continue prescribing antidepressants, but should remain especially vigilant when prescribing antidepressants to people with coronary artery disease.
Blumenthal's co-author Lana Watkins presented the team's work on 4 March at the annual meeting of the American Psychosomatic Society in Denver, Colorado.