People who are diagnosed with coronary artery disease and then develop depression face a risk of death that’s twice as high as heart patients without depression. This is according to a major new study by researchers at Intermountain Healthcare in Salt Lake City.
The increased risk of death from any cause holds true whether the depression immediately follows the heart disease diagnosis or occurs even years later, according to Heidi May, PhD, a cardiovascular epidemiologist at Intermountain Medical Center Heart Institute and the study’s lead author.
She said the findings point out the importance of screening for and treating depression even years after someone is diagnosed with heart disease.
Biggest predictor of death
Researchers found that post-coronary artery disease depression was the single biggest predictor of death and remained so even after researchers controlled for the other factors.
“No matter how long or how short it was, patients were found to have twice the risk of dying compared to those who didn’t have a follow-up diagnosis of depression,” Dr. May said. “Depression was the strongest risk factor for dying, compared to any other risk factors we evaluated. That included age, heart failure, diabetes, high blood pressure, kidney failure, or having a heart attack or stroke.”
That association didn’t change for patients who were previously diagnosed with depression before their heart disease diagnosis or for patients whose angiograms were performed for various reasons, which included stable angina, unstable angina, or heart attack.
Dr. May said most studies have looked at depression at a single point in time, such as within 30 days of a heart event or at the time of heart disease diagnosis. Just a handful of studies have looked over the course of a year, let alone years, such as this study, which followed patients for an average of 10 years after their coronary artery disease diagnosis to see if they were ever diagnosed with depression.
Fifteen percent diagnosed with depression
In all, 15 percent, or 2,646 patients, were diagnosed with depression at some point during follow-up. Of those, 27 percent were diagnosed within a year of their heart event, 24 percent between one and three years after, nearly 15 percent between three and five years after, and nearly 37 percent at least five years after a baseline heart disease event.
Study reinforces previous research
This study reinforces previous research investigating the link between depression, heart disease, and increased risks of death. It’s already been shown that people with coronary artery disease don’t live as long as their peers who don’t have heart disease. And while life expectancy has increased with better therapies, surgeries, and more aggressive treatment of identified risk factors, depression has come under increasing scrutiny as a risk factor that could make a difference, if properly treated.
The study didn’t explain the reason for the elevated risk of death, although Dr. May said one possibility is that depression impacts how closely patients follow their treatment plans.
She also noted that physiological changes occur within the body when patients are diagnosed with depression, which might help explain the link.
The researchers emphasize the importance of continual screening of depression for all heart disease patients. “Patients who have depression need to be treated for it to improve not only their long-term risks but their quality of life,” Dr. May said.
The Intermountain Medical Center Heart Institute is part of the Intermountain Healthcare system, which is based in Salt Lake City.
