Montreal, QC - A new study confirms that patients with stable CAD and a diagnosis of depression or anxiety have a greater risk of cardiac events [1].

Patients with concomitant diagnoses of stable CAD and either major depressive disorder (MDD) or generalized anxiety disorder (GAD) had a greater-than-twofold increase in the risk of major adverse cardiac events (MACE) in the two years following a baseline assessment, although comorbid MDD and GAD appeared not to be additive in their effects on cardiac risk.

The report, by Drs Nancy Frasure-Smith (McGill University, Montreal Heart Institute Research Center, Centre Hospitalier de l'Université de Montréal Research Center and the University of Montreal, QC) and François Lespérance (Montreal Heart Institute Research Center, Centre Hospitalier de l'Université de Montréal Research Center, and the University of Montreal), appears in the January 2008 issue of the Archives of General Psychiatry.

Both anxiety and depression have been associated with mechanisms that promote atherosclerosis, but most of the work to date has focused on depression only, largely ignoring the potential impact of anxiety or the combination of these conditions on the risk for CAD events, the authors write.

The work that has shown apparent links between anxiety and prognosis in cardiac patients has largely explained this association by other factors such as disease severity, Frasure-Smith said. However, both GAD and MDD have many overlapping symptoms and some genetic links, and antidepressants can be used to treat both conditions, leaving open the question of a prognostic association between anxiety and cardiac prognosis.

The aims of the present analysis, from the Epidemiological Study of Acute Coronary Syndromes and the Pathophysiology of Emotions (ESCAPE), was to examine the relationship between Diagnostic and Statistical Manual of Mental Disorders, 4th ed (DSM-IV)-based diagnoses of MDD and GAD in patients with stable CAD, as well as self-reported symptoms of anxiety and depression assessed approximately two months after hospital discharge for acute coronary syndromes, on the risk for subsequent cardiac events over two years.

The researchers also looked at whether the combination of anxiety and depression might further increase the two-year MACE risk over that seen with either condition alone.

Included in the study were 804 patients with stable CAD, 649 of whom were men. All were assessed at two months after hospital discharge using the Beck Depression Inventory II (BDI-II), the anxiety subscale of the Hospital Anxiety and Depression Scale (HADS-A), and the structured clinical interview of the DSM-IV, masked to the self-reports of symptoms.

Patients were then followed up at two years for the occurrence of MACE, including cardiac death, MI, cardiac arrest, or nonelective revascularization.

The authors report that the prevalence of depression, although not as high as in hospitalized CAD patients, was higher than in the general community of people with stable cardiac disease. The prevalence of GAD was almost as high, and the prevalence of both conditions was higher than in the general population, said Frasure-Smith.

Of the 804 patients, 57 (7.1%) met the criteria for MDD and 43 (5.3%) for GAD; 11 patients (1.4%) had comorbidity of both conditions. A total of 220 (27.4%) had elevated depression symptoms, with BDI-II scores of 14 or higher, and 333 (41.4%) had elevated HADS-A scores of 8 or greater, with overlap occurring in 21.1%.

Both GAD and MDD predicted the occurrence of major cardiac events over the two-year period; both conditions were associated with approximately a doubling of risk, even after adjustment for multiple background and cardiac disease severity measures.

"Although before covariate adjustment there was evidence of increased risk with elevated self-report symptoms, even in the absence of meeting DSM-IV criteria, after covariate control only the increased risks associated with MDD and GAD remained significant," the authors write.

However, patients with comorbid MDD and GAD or elevated symptoms of both anxiety and depression on self-report were not at greater risk for subsequent MACE than those with only one of these conditions.

"We know that generalized anxiety disorder is difficult to treat and really affects people's quality of life and their ability to function," Frasure-Smith said. "But until now, we didn't know that any psychiatric condition besides major depression and possibly panic disorder might also have cardiac prognostic implications.

"This suggests that when you see someone with comorbid GAD and cardiac disease, comorbid MDD and cardiac disease, special attention needs to be paid to them, both from the point of view of their psychiatric condition, but also in controlling their other risk factors," she concluded. "We don't have evidence that psychiatric treatment for either of these conditions will affect cardiac outcome, but we do know that cardiac risk factor control affects cardiac outcomes, so these are patients at high risk who should be receiving the best evidence-based cardiac medications and treatment that we can provide."