New York, April 8 (IANS): Depression, even when undiagnosed, can have many negative effects on patients with cardiovascular diseases, including poor healthcare experiences and higher health costs, say researchers.

The study found that people at high risk of depression were more than five times more likely to have a poor self-perceived health status and almost four times more likely to be dissatisfied with their healthcare.

Patients at high risk of depression had notably worse healthcare-related quality of life. They spent more on overall and out-of-pocket healthcare expenditures yearly.

They were more than two times more likely to be hospitalised and have an increased use of the emergency room, said the researchers while presenting the results at the American Heart Association's Quality of Care and Outcomes Research Scientific Sessions 2018 in Virginia.

"This could be because people at high risk for depression simply haven't been diagnosed and treated for depression yet," said Victor Okunrintemi, a research student at Baptist Health South Florida, a US-based non-profit.

In another study, the team found that heart attack patients diagnosed with depression were 54 per cent more likely to be hospitalised and 43 per cent more likely to have emergency room visits, compared to those not diagnosed with depression.

"Depression and heart attack often coexist, which has been associated with worse health experiences for these patients," Okunrintemi said.

About one-fifth of cardiovascular disease patients suffer from depression.

"While we don't know which comes first -- depression or cardiovascular disease -- the consensus is that depression is a risk marker for cardiovascular disease," Okunrintemi said.

It means that "if you have cardiovascular disease, there is a higher likelihood that you could also have depression, when compared with the risk in the general population", he added.