TUESDAY, Jan. 3 (HealthDay News) -- People who have heart attacks in the United States are far more likely to be readmitted to the hospital within 30 days than people in 16 other countries, a new study indicates.

Researchers suspect that the average length of stay, which was just three days in the United States compared with at least six days in other countries, is the main reason for the higher readmission rates. When they completed an analysis that adjusted the data for length of stay, they found that location was no longer a predictor of readmission.

"We found two striking predictors of 30-day readmission. Having multi-vessel disease and being in the U.S. This difference is probably multifactorial, but the length of stay is the shortest in the U.S. It was three days here and six, seven or more in other countries," said study senior author Dr. Manesh Patel, an assistant professor of medicine in the division of cardiology at Duke University in Durham, N.C.

"When we adjusted for the length of stay, the difference went away. We're really good at opening up their arteries, but we provide more episodic care. Our systems of care may not be as integrated as they are in other countries. We need to make the link from the hospital to the primary care doctor to ensure that patients are getting set up in cardiac rehab and that they're following up with a cardiologist," Patel said.

And, while the study found that U.S. patients had higher readmission rates after a heart attack, Patel noted that mortality rates weren't higher in the United States.

Results of the study are published in the Jan. 4 issue of the Journal of the American Medical Association.

The study looked at people who were hospitalized for a specific type of heart attack called an ST-segment elevation myocardial infarction (STEMI). This type of heart attack accounts for up to 38 percent of all heart attacks, according to background information in the article, and the coronary artery is completely blocked by a clot in these cases.

The study included 5,745 people from 296 hospitals in 17 countries who were admitted for a STEMI. Most (5,571) survived to be discharged from the hospital. Of those, 11.3 percent overall ended up being readmitted within 30 days.

Thirty-day readmission rates in the United States were 14.5 percent, but just 9.9 percent in the other countries in the study. The average length of stay was three days in the United States compared with eight days in Germany, the country with the longest average length of stay.

People who had multi-vessel disease, which means they had more than one blockage leading to the heart, were almost twice as likely to be readmitted to the hospital within 30 days, according to the study.

The other significant predictor of readmission within 30 days was being in the United States. After excluding people returning to the hospital to have additional elective procedures, people admitted in the United States had a 53 percent greater chance of being readmitted within 30 days vs. people in other countries.

After adjusting the data to account for differences in the patients, such as age and underlying health conditions, the researchers found a 14.4 percent readmission rate in the United States vs. a 9.3 percent rate for all of the other countries. Italy had the lowest readmission rates at 4.4 percent, followed closely by Germany at 4.8 percent. Canada had a 5.6 percent adjusted readmission rate, according to the study.

"This study compared the U.S. against 16 other countries and asked how do we [the U.S.] measure up? And, their findings were a little disturbing. About 60 percent of patients with major heart attacks were discharged in three days or less. And, our readmission rates were higher than in other countries. We have the technology and the ability to provide quality care, but we're just not doing well. Even for the sickest patients, we're not doing well," said Dr. Suzanne Steinbaum, a preventive cardiologist at Lenox Hill Hospital in New York City, and a spokesperson for the American Heart Association.

"This is probably not just about length of stay, but may also be about follow-up. It might really be OK to leave the hospital in three days, but you have to understand what the follow-up is. You need to understand the treatment plan, the medications, the follow-up appointment schedule, the cardiac rehab and the diet. If these things are all in place, readmission rates would probably go down," Steinbaum said.

"We're not sure that staying in the hospital longer would keep you from being readmitted. We know we provide good initial care. But, how well is that care transferred from the hospital to the home? We have to make sure patients know how they need to follow up," Patel said.

More information

Learn more about what type of care is necessary after a heart attack from the U.S. National Heart, Lung, and Blood Institute.