U.S. readmission rate after STEMI higher than in other countries, post hoc analysis indicates

The readmission rate following ST-segment elevation myocardial infarction (STEMI) treatment is higher in the United States than it is in several other countries, according to a retrospective analysis of clinical trial data. Researchers conducted a post hoc analysis of data from the Assessment of Pexelizumab in Acute Myocardial Infarction trial, which included 5,745 patients with STEMI in 17 countries. In the trial, Procter & Gamble Co. and Alexion Pharmaceuticals Inc.'s experimental...

The readmission rate following ST-segment elevation myocardial infarction (STEMI) treatment is higher in the United States than it is in several other countries, according to a retrospective analysis of clinical trial data.

Researchers conducted a post hoc analysis of data from the Assessment of Pexelizumab in Acute Myocardial Infarction trial, which included 5,745 patients with STEMI in 17 countries. In the trial, Procter & Gamble Co. and Alexion Pharmaceuticals Inc.'s experimental therapy pexelizumab was compared with placebo. The treatments were administered immediately before primary percutaneous coronary intervention (PCI) was performed on high-risk patients with STEMI within six hours of symptom onset.

The primary endpoint of the current analysis was 30-day all-cause hospital readmission following discharge, with a secondary endpoint of 30-day nonelective readmission following discharge, which excluded readmissions for elective PCI or coronary artery bypass grafting (CABG).

Of the entire cohort, 5,571 patients survived to discharge. Of those patients, 631 (11.3 percent) were readmitted within the following 30-day period. A significantly higher percentage of the U.S. patients in the overall cohort were readmitted within the 30 days after discharge as compared with those living in all other countries (14.5 percent vs. 9.9 percent, respectively).

When readmissions for elective revascularization were omitted, 478 patients from the overall cohort were readmitted within 30 days of discharge, representing 10.5 percent of the U.S. patients overall and 7.7 percent of the patients who lived elsewhere.

Relative to the patients who were not readmitted, those who were rehospitalized had significantly higher rates of comorbidities, including previous coronary artery disease (15.5 percent vs. 20.9 percent), hypertension (48 percent vs. 56.7 percent) and diabetes (15.2 percent vs. 18.7 percent). They were also significantly more likely to have multivessel disease (38.2 percent vs. 57.1 percent) and noninferior myocardial infarction (58.1 percent vs. 63.9 percent). In addition, they were more likely to have a hospital stay that exceeded six days.

A significantly greater proportion of the patients who were readmitted resided in the United States as compared with the patients who were not readmitted (39.1 percent vs. 29.4 percent).

Among the overall cohort, the patients from the United States were somewhat younger than those from other countries (median age, 58 years vs. 62 years), and a significantly higher proportion of those from the United States were black patients (7.1 percent vs. 0.2 percent).

Of note, the length of stay was significantly shorter for the U.S. patients than for those living in other countries. For example, 60 percent of the U.S. patients had a stay of three days or less, whereas just 15.9 percent of the patients in other countries had a similar length of stay. Conversely, 54 percent of the patients living elsewhere had a stay of six days or longer, while only 16.6 percent of the U.S. patients remained in the hospital that long. The study authors said these findings raise the possibility that higher U.S. readmission rates could be an adverse effect of reduced lengths of stay in this country.

The U.S. patients had significantly higher rates of readmission for elective PCI and significantly lower rates of readmission for elective CABG as compared with the patients who lived in other countries.

After adjusting for baseline characteristics, the strongest predictors of 30-day readmission were multivessel disease (nearly double the risk as compared with no multivessel disease) and U.S. enrollment (a 68 percent greater risk vs. other countries). When elective readmissions for PCI or CABG were excluded, multivessel disease was no longer significantly associated with readmission, but U.S. enrollment continued to be, although the association was diminished.

The odds of 30-day readmission were significantly lower in Italy, Germany, Canada,
Portugal, the Netherlands and the Czech Republic than in the United States. Denmark and Sweden had higher odds than the United States, but neither of those comparisons was statistically significant.

The researchers noted that when they adjusted their models of all-cause and nonelective readmissions for country-level median length of stay, U.S. enrollment was no longer a significant predictor of 30-day readmission.

The authors said their analysis demonstrates that readmission following STEMI might be preventable, since rates were almost one third lower in other countries than in the United States. They added that additional research is needed to better understand the relationship between length of stay and readmission rates.

The results of the analysis were published in the Jan. 4 issue of JAMA.

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