Depression Increases Health Risks in Heart Failure Patients
DURHAM, N.C. – Psychological depression appears to
contribute to worse medical outcomes for patients with heart
failure, ranking it in importance with such risk factors as
high cholesterol, hypertension, and even the ability of the
heart to pump blood throughout the body.
After taking into account such factors as disease severity,
the strength of the heart muscle contractions, the underlying
cause for the heart failure, age and medication use, a team of
Duke University Medical Center and University of North Carolina
researchers found that symptoms of depression were common in
this population, and that depressed patients were over 50
percent more likely to die or be hospitalized for their heart
condition than patients who were not depressed.
Heart failure, also known as congestive heart failure, is
marked by the inability of the heart muscle to pump enough
oxygen and nutrients in the blood to the body's tissues. A
variety of factors can cause heart failure, including
infections of the heart, coronary artery disease, high blood
pressure, previous heart attacks and a malfunctioning heart
valve. An estimated 4.7 million Americans have heart failure,
with 400,000 new cases reported each year, and it is the only
cardiovascular disease that is rising in incidence, according
to the researchers. About half of heart failure patients will
die within five years of diagnosis.
"While many studies have linked depression to worse outcomes
for patients with heart disease, there has been uncertainty
about the extent to which depression is related to the adverse
medical outcomes independent of known medical risk factors,"
said James Blumenthal, Ph.D., co-author of the study and a
clinical psychologist at Duke.
The researchers reported the results Monday in the Monday,
Feb. 26, 2007 edition of the Archives of Internal Medicine. The
study was funded by the National Institutes of Health.
For their study, the researchers enrolled 204 stable heart
failure patients. Each patient took a standard battery of
psychological tests to assess symptoms of depression. Forty-six
percent demonstrated significant depressive symptoms. Patients
were followed for an average of three years. During that time,
26 percent died and 48 percent were hospitalized at least once
for their heart condition.
What made this analysis different from other such studies
was that the researchers coupled the psychological assessment
with a relatively new blood test that measures what are known
as "B-type natriuretic peptides." These chemicals are released
into the bloodstream by the heart tissue when the heart is
unable to pump effectively. The chemicals serve as a signal to
the kidneys to produce more urine, which in turn reduces the
volume of blood fluid, making it easier for damaged or weakened
heart muscle to pump blood.
Elevated levels of B-type natriuretic peptides have been
previously shown to be associated with increased risk of death
for heart attack patients and are now being used in the
diagnosis of heart failure.
"As expected, high levels of BNP predicted worse outcomes in
our study, but even taken this and other disease makers into
account, we found that depressive symptoms were still
independently associated with worse outcomes," said study lead
investigator Andrew Sherwood, Ph.D., medical psychologist. "Our
findings underscore the importance of assessing heart failure
patients for depression, so that where treatment is indicated,
both the quality and quantity of their lives may be
Researchers still don't understand why depressed heart
patients have worse outcomes. Among possible factors, depressed
patients are known to have overly active immune systems, a
decrease in the ability of their blood platelets to clot
properly and a decrease in their heart's ability to react
appropriately to the stresses of everyday life. Depressed
patients also may be less likely to comply with their medical
treatments, may not be as motivated to stick with exercise or
rehabilitation programs, may miss doctor's appointments and
tend to make unhealthy lifestyle choices in such areas as diet
In an attempt to better understand the role of depression in
the fate of heart patients, the researchers are currently
enrolling patients in a new clinical trial to measure the
effects of exercise and antidepressant medications on specific
physiological indicators of heart disease. The trial, supported
by the National Institutes of Health, has been dubbed UPBEAT --
short for "Understanding the Prognostic Benefits of Exercise
and Anti-Depressant Therapy in persons with cardiac disease."
Patients with stable coronary disease and symptoms of
depression receive 16 weeks of exercise or pill therapy.
The researchers believe that the results of their current
analysis, as well as their ongoing trial, will provide guidance
for physicians in treating patients with heart failure and
coronary artery disease who are also exhibiting signs of