People who are married are more likely to bounce back after heart surgery than those who are divorced, separated or widowed, US researchers said Wednesday.

The study in the Journal of the American Medical Association (JAMA) Surgery was based on data from more than 1,500 people.

Two-thirds were married, 12 percent were divorced or separated, 21 percent were widowed and two percent were never married.

Going into surgery, the married participants already tended to be healthier than their counterparts.

And after surgery, "marital status was significantly associated with death or a new functional disability," said the study.

"Participants who were divorced, separated, or widowed had an approximately 40 percent greater odds of dying or developing a new functional disability during the first two years after cardiac surgery compared with the married participants."

After surgery, 19 percent of married participants died or developed a new disability, compared to 29 percent of divorced people and 34 percent of the widowed participants.

One in five of those who had never married either died or experienced a post-surgery complication, leaving them unable to perform a common daily activity such as dressing, walking or eating.

"These findings extend prior work suggesting postoperative survival advantages for married people and may relate to the role of social supports in influencing patients' choices of hospitals and their self-care," said the study.

The findings suggest "that marital status is a predictor of survival and functional recovery after cardiac surgery."