Heart attack patients in U.S. more likely to be readmitted to the hospital than patients in other countries

Heart attack with ST-segment elevation accounts for 29 percent to 38 percent of all heart attacks. "In the present era of primary percutaneous coronary intervention [PCI; procedures such as balloon angioplasty or stent placement used to open narrowed coronary arteries], survival to hospital discharge has improved dramatically. Subsequently, patients who survive to hospital discharge are at risk for early postdischarge hospital readmission," according to background information in the article. "Recently, 30-day readmission rates have been proposed as a metric for care of patients with STEMI. However, international rates and predictors of 30-day readmission after STEMI have not been studied."

Robb D. Kociol, M.D., of Duke University Medical Center, Durham, N.C., and colleagues analyzed data from the Assessment of Pexelizumab in Acute Myocardial Infarction study, a large multinational clinical trial, to determine international variation in and predictors of 30-day readmission rates after STEMI and country-level care patterns. The trial enrolled 5,745 patients with STEMI at 296 sites in the United States, Canada, Australia, New Zealand, and 13 European countries from July 2004 to May 2006. Analysis was performed to identify predictors of all-cause and nonelective 30-day postdischarge hospital readmission.

Of the patients enrolled in the trial, there were 5,571 (97.0 percent) included in the analysis who survived to hospital discharge and represented 17 countries; 631 (11.3 percent) were readmitted within 30 days from hospital discharge. The researchers found that factors associated with 30-day readmission were multivessel coronary artery disease, U.S. enrollment (vs. rest of the world), and baseline heart rate. Patients with multivessel disease had almost twice the odds of readmission compared with those without; patients in the United States had a 68 percent increased odds of readmission vs. those outside the United States; and baseline heart rate per 10/min increase was associated with a 9 percent increased odds of readmission.

Thirty-day readmission rates were higher for the United States than other countries (14.5 percent vs. 9.9 percent). Median (midpoint) length of stay was shortest for U.S. patients (3 days) and longest for patients in Germany (8 days).

"Excluding elective readmission for revascularization, U.S. enrollment was still an independent predictor of readmission. After adjustment of the models for country-level median length of stay, U.S. location was no longer an independent predictor of 30-day all-cause or nonelective readmission. Location in the United States was not a predictor of in-hospital death or 30-day postadmission death," the authors write.

Other predictors of readmission included recurrent ischemia, chronic obstructive pulmonary disease, chronic inflammatory conditions, and a history of hypertension.

The authors write that the finding that STEMI patients in the United States have a higher likelihood of 30-day all-cause hospital readmission may be related to differential rates of early readmission for elective revascularization and shorter median length of stay (LOS) in the United States. "In particular, country-level median LOS attenuates the relationship between the United States and early readmission. Further research is needed to better understand the relationship between LOS and readmission rates and define and optimize overall efficiency of care internationally."

"Significant attention has been focused on reducing acute myocardial infarction readmission rates in the United States as a means of reducing health care costs, according to the assumption that readmission is (at least in part) preventable. Our analysis shows that readmission may be preventable because rates are nearly one-third lower in other countries, suggesting that the U.S. health care system has features that can be modified to decrease readmission rates. Understanding these international differences may provide important insight into reducing such rates, particularly in the United States."