SALT LAKE CITY — The relationship between depression and heart disease is a complicated one at best.
People with depression have been shown to have a higher risk for heart disease, suffer worse cardiac outcomes and have higher death rates after cardiac surgery. However, heart disease and heart surgery has also been shown to trigger depression in patients.
Researchers at Intermountain Medical Center Heart Institute are trying to untangle the links between the two diseases.
They compared the surgical outcomes of 118 heart patients with and without depression and found that patients with moderate to severe depression had a death rate four times higher than those without depression.
In a surprising twist, however, they also found that the risk of death could be cut by 74 percent with cardiovascular rehabilitation.
"To see it benefit mental health is a little surprising," said physician assistant and lead author Viet Le.
Cardiac rehabilitation is a standardized treatment that involves bringing in patients two to three times a week for exercise and supervision. While the program teaches patients about smoking and nutrition, it does not generally address depression, Le said.
“We do get people out of their house and probably out of their own head,” he said.
Le speculates that having a support group of medical professionals and fellow patients allows people to manage their expectations.
"You have people who normalize the disease,” Le said. “It's no longer, 'Oh, I'm diseased.' You have others that also have the disease and say, 'This is normal and we're all healing at the same rates.'"
The study added to a growing body of evidence that depression and cardiac health are intertwined.
Among the 98 patients who reported little to no depression, the rate of death was 6 percent.
But among the 20 patients who reported moderate to severe depression, the death rate after cardiovascular surgery was 25 percent.
“It’s a ‘chicken or the egg’ problem,” Le said. “Are you depressed and you have coronary disease, or do you have coronary disease and develop depression, or is a little bit of both?”
Le and his colleagues presented their findings at the 2016 American Heart Association's Scientific Session in New Orleans on Sunday.
Although the study is small and the conclusions that can be drawn are limited, Le said he is looking to expand the research and collaborate with other health systems.
One question he has is why certain patients are opting in or out of rehab.
Research has shown that a clinician’s referral to rehab has a big influence on whether patients end up going, Le said. Nationally, the referral rate is less than 40 percent. At Intermountain Medical Center, the referral rate is closer to 85 percent.
"Going forward, we really need to focus on those that are identified as having moderate to severe depression before going into surgery," Le said. "Perhaps we focus on them a little bit more aggressively to get them to cardiac rehab."