People with heart failure are also more likely to be diagnosed with cancer,
according to a new study that followed older adults with and without heart
The findings don't prove that heart failure, when the heart can't pump enough
blood to the rest of the body, causes cancer. Researchers said more studies are
needed to determine what might explain the link.
"People have not really considered any association of heart failure and
cancer together, at least not developing cancer after diagnosis," said Dr Adrian
Hernandez, a cardiologist at the Duke University School of Medicine in Durham,
But Dr Sudhir Kushwaha, who worked on the study at the Mayo Clinic in
Rochester, Minnesota, said the association makes sense, because a lack of blood
and oxygen could create problems in many organs.
"The (heart failure) patient should be aware or alert to any new symptoms
that might develop," he said.
Close to six million Americans have heart failure, according to the US
Centers for Disease Control and Prevention.
Symptoms include trouble breathing and fatigue. For the new study, the
researchers matched 961 newly-diagnosed heart failure patients with people of
their same age and gender that didn't have the disease. A similar proportion of
those participants - 22% to 23% - had already had cancer.
There were 596 cancer-free study pairs, who the researchers then followed,
starting when participants were an average of 73 years old. Over the next eight
years, 244 people still in the study were diagnosed with cancer, including colon
cancer, prostate cancer, breast cancer and blood cancers.
After accounting for certain disease risks such as people's weight and
whether they smoked, Kushwaha and his colleagues calculated that heart failure
patients were 68% more likely to be diagnosed with cancer than their heart
Although people with heart failure were sicker in general - with more
diabetes and high blood pressure, for example - that didn't explain their
greater cancer risk, the study team wrote in the Journal of the American College
Kushwaha's group said there are a few possible explanations for the link, all
of which need more study. Certain heart drugs could increase cancer risks, or
stress and inflammation from heart failure itself might play a role, as could
lack of oxygen.
It's also possible the link can be explained by people with heart failure
seeing their primary care doctors more often and thus getting more screening
tests, researchers said.
"Sicker people tend to be seen in medical encounters all the time they get
more lab tests, more people ask them whether they want to be screened," said Dr
Jersey Chen, a cardiology researcher from Kaiser Permanente's Mid-Atlantic
Permanente Research Institute in Rockville, Maryland.
"That may explain why the difference seems to be this high," said Chen, who
wasn't involved in the new research.
Kushwaha, however, said that explanation was unlikely - both because the
difference in cancer rates took a couple of years to show up, and because people
without heart failure still saw their doctors regularly.
According to Hernandez, who didn't participate in the study, the next step
will be to follow people with and without heart failure, taking into account
exactly how many tests they receive. Chen agreed that type of data is needed to
figure out the underlying association.
"I wouldn't make patients worry about this, that either they have a higher
risk of cancer right now or that they should change their medications or
treatments," he said.
"I think it's way too preliminary to invite those kinds of clinical