Kent State Epidemiologist Leads Study That Refutes Assumptions About Depression In Heart Attack Patients

Studies have shown that people who suffer from depression are more likely to have heart disease or heart attacks in their lifetime. Worse still, similar research shows that heart patients who have depression face lower survival rates.

For decades, conventional wisdom has fostered the idea that heart attack patients with clinical diagnoses of depression also are not likely to enroll in cardiac rehabilitation programs, adding to the already high likelihood of an unfavorable prognosis.

The study led by Dr. Melissa D. Zullo, Associate Professor of Epidemiology in Kent State’s College of Public Health, however, reveals that heart-attack patients with depression diagnoses were four times more likely to enroll in cardiac rehabilitation programs than those who did not have a diagnosis of depression.

“The data also showed that patients with depression were more likely to complete cardiac rehab compared to those without depression,” Zullo said. “What these findings mean to the medical community is that referring depressed patients to cardiac rehab is not a waste of time or resources because they do go and they do complete the program.”

The study, which will soon be published in the Journal of Cardiopulmonary Rehabilitation and Prevention, looked at 158,000 Medicare recipients aged 65 to 90, who had suffered heart attacks in 2008. Medicare data collections are available for study on multiple chronic conditions. Zullo accessed billing records from 2008 and 2009 for the study.

She then teamed up with Kent State Psychological Sciences Professor, Dr. Joel Hughes; University Hospitals Cardiologist, Dr. Richard Josephson; Dr. Mary Dolansky, Associate Professor of Nursing at Case Western Reserve University; Assistant Professor of Biostatistics at Kent State, Dr. Vinay Cheruvu; and psychology grad student Emily Gathright.

From a population size of more than a couple hundred thousand heart attack patients over the age of 65, the team whittled the sample down to 158,000, screening out patients who had died after the heart-attack incident, those over 90, those with schizophrenia or other severe psychological disorders, those who entered long-term nursing care after the event, and those who had entered into cardiac rehab prior to the heart attack for a previous event. Within the qualified sample, they found 43,827 (28 percent) patients who had been billed during the study period for clinical depression services.

According to the study, 28 percent of patients with a depression diagnosis — compared to 9 percent of those without a depression diagnosis — attended rehab.

“We were so shocked, that we thought we had done the study wrong, we re-checked it again and again. It’s not a fluke,” Hughes said. “This means that people with depression can enroll in cardiac rehabilitation and should be told to enroll, because we have hard evidence now that says they will follow through.”

Zullo and Hughes said the study also shows that the number of patients enrolling in cardiac rehab after heart attacks is still too low — only 14 percent of patients in the total sample actually enrolled.

“Cardiac rehabilitation is intended to meet the psychosocial and physical needs of the patient,” said Dr. Josephson. “That depressed patients are using the service means they are receiving a benefit that is treating their depression and may be counteracting the negative depression-related outcomes.”

Paul E. DiCorleto, Kent State’s Vice President for Research, said the study offers profound insight that will lead to greater success for many cardiac patients.

“The whole team should be commended,” he said. “This study is a great example of an interdisciplinary team coming together to answer a question that will lead to a direct impact on patient care.”

Zullo stressed that the data only pertains to Americans on Medicare, and that studies on depressed heart attack patients who fall into other demographics could yield different results.

Still, she acknowledges that the study presents the potential for further research, which she and her team hope will explain the one big question they haven’t answered: why is this happening?

“We aren’t sure why depressed patients seem to be more compliant, but it may be due to cardiac rehab staff encouraging them to stay in rehab, or it may be because they feel better and decide to stay longer,” she said.