Depressed patients with coronary artery disease are twice as likely to die compared to heart patients without depression, according to new research.
The study, conducted by scientists at Intermountain Healthcare in Salt Lake City, was led by Heidi May, PhD, a cardiovascular epidemiologist at Intermountain Medical Center Heart Institute. The research was published in the European Heart Journal-Quality of Care & Clinical Outcomes.
"We've completed several depression-related studies and been looking at this connection for many years," May said in a statement. "The data just keeps building on itself, showing that if you have heart disease and depression and it's not appropriately treated in a timely fashion, it's not a good thing for your long-term well-being."
The study included more than 24,000 patients who underwent angiographies and were diagnosed with coronary artery disease. Patients were also assessed for depression.
Results showed that post-coronary artery disease depression was the single largest predictor of death, even when other factors were considered and controlled.
About 15 percent of patients, or 2,646 patients, were diagnosed with depression at some point during follow up. Of those, 27 percent were diagnosed within a year of a cardiac event, 24 percent were diagnosed between one and three years after an event, almost 15 percent were diagnosed between three and five years later and about 37 percent were diagnosed after five years.
"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," 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."
The study didn’t explain why there is an elevated risk of death, but May said it could serve as the groundwork for future studies that explore that. But she hopes that her study encourages physicians to continuously screen heart patients for depression.
"I hope the takeaway is this: it doesn't matter how long it's been since the patient was diagnosed with coronary artery disease. Continued screening for depression needs to occur," May said. “After one year, it doesn't mean they're out of the woods. It should be ongoing, just like we keep measuring things like LDL cholesterol."