NEW ORLEANS — Depression is common among patients with heart failure and is independently associated with poor outcomes, Dr. Aldo P. Maggioni said at the annual meeting of the American College of Cardiology.
He presented a retrospective study involving 18,623 patients with heart failure over age 60 identified in an administrative health care database covering two regions of Italy. At entry, 13% were being treated for depression.
In a multivariate logistic regression analysis, comorbid depression was independently associated with a highly significant 28% increased risk of all-cause mortality at 1 year, compared with the risk in heart failure patients not treated for depression.
Depression also was associated with an adjusted 36% increased risk of a 1-year composite end point consisting of MI, stroke, or transient ischemic attack, along with an 18% increase in all-cause hospitalization. However, the risk of rehospitalization for heart failure was no greater in patients treated for depression than in those who weren't, according to Dr. Maggioni, a cardiologist at the Mario Negri Research Consortium South, Santa Maria Imbaro, Italy.
He noted that while the adverse effect of comorbid depression on outcomes in patients with coronary artery disease is well established, there is much less evidence regarding the mood disorder's effect in patients with heart failure. Most previous studies have been quite small.
The strength of the new Italian study is its very large numbers. Its weakness is that there was no systematic screening for depression, so it's entirely possible the “nondepressed” comparator group included a fair number of heart failure patients with undiagnosed and untreated depression. Regardless, Dr. Maggioni said, the study conclusion was essentially the same as in the much smaller studies in which heart failure patients were screened for depression by questionnaire or interview: Depression is associated with poor outcomes in heart failure.
The mean age of participants in this study was 78 years. Patients treated for comorbid depression were significantly older than those who weren't. Sixty-nine percent were women, compared with 58% of heart failure patients not treated for depression.
Patients with depression also were significantly more likely to have a baseline history of stroke, transient ischemic attack, cancer, and chronic obstructive pulmonary disease.
Dr. Maggioni offered three potential explanations for the worse clinical outcomes in heart failure patients treated for depression. One possibility is that some antidepressant medications might have adverse effects in this population. Another is that depression exacerbates the underlying pathophysiology of heart failure, which is plausible in light of the fact that both conditions involve increased sympathetic nervous system activity, platelet activation, and systemic inflammation. But the most likely explanation for the association, in Dr. Maggioni's view, is that depressed patients have less social support and are less adherent to their cardiovascular therapy.
The big unanswered question is whether treatment of depression improves heart failure outcomes, he said. There are no data, and a definitive randomized clinical trial would need to be very large.
“You need the numbers. If you're testing a new drug, just to see a 15% relative difference in mortality, you need perhaps 7,000 patients,” Dr. Maggioni noted in an interview.
Session Chair Douglas P. Zipes called the Italian report linking depression to worse outcomes in heart failure “a very important observation” regarding an issue that doesn't receive sufficient attention from nonpsychiatrists.
“I think we tend to focus on more tangible issues, such as which coronary artery is occluded [and] the warfarin dose. My impression is that issues such as depression, sexual activity, and support groups aren't discussed at length–and they should be,” said Dr. Zipes, Distinguished Professor of Medicine, Pharmacology, and Toxicology at Indiana University, Indianapolis.
Depressed patients have less social support and are less adherent to their cardiovascular therapy. DR. MAGGIONI