Heart disease has become increasingly common in the U.S., with one in four deaths attributed to the condition.

And for heart disease patients being single doesn't help, new research published in the Journal of the American Heart Association found.

Researchers looked at 6,051 heart disease patients over an average of 3.7 years, and kept track of whether or not they were married. They found that unmarried people were at a 24% higher risk of death from any cause, a 45% higher risk of death from cardiovascular disease, and a 52% higher risk of death from a heart-related event or heart attack.

Even in the general population being unmarried is associated with dying younger, but this is the first study to suggest a connection between marital status and heart disease-related death risk.

The study also broke down the data according to whether patients were never married, divorced or separated, or widowed. Never-married people were 40% more likely to die from a heart attack; divorced or separated people were 41% more likely; and widowed people were 71% more likely.

Of course, it's important not to draw too many conclusions from even large epidemiological studies like this. More research is needed to figure out exactly why a single life could spell trouble for heart disease patients, and how doctors can adjust treatments to lower that risk.

“I was somewhat surprised by the magnitude of the influence of being married has [on heart patients],” lead researcher Arshed Quyyumi, M.D., told the American Heart Association. “Social support provided by marriage, and perhaps many other benefits of companionship, are important for people with heart disease.”