30-day mortality rates following NSTEMI are similar at low- and high-utilization ICU hospitals

The 30-day mortality rates for older adults with non-ST segment elevation MI (NSTEMI) were not significantly different whether they were treated at a high-, intermediate- or low-use intensive care unit (ICU) hospital, according to a retrospective analysis of Medicare data.

Lead researcher Alexander C. Fanaroff, MD, of the Duke Clinical Research Institute in Durham, North Carolina, and colleagues published their results Nov. 2 in JAMA Cardiology.

Each year, 450,000 patients are hospitalized for NSTEMI, according to the researchers. They added that guidelines recommend those patients are managed in an ICU, coronary care unit or monitored bed.

In this study, the researchers evaluated 28,018 patients who were admitted with NSTEMI from April 1, 2011, through Dec. 31, 2011, to 346 hospitals that participated in the Acute Coronary Treatment and Intervention Outcomes Network (ACTION)–Get With the Guidelines program. They excluded patients who were admitted to the hospital with cardiac arrest or cardiogenic shock.

The patients were at least 65 years old and had Medicare coverage. The median age was 77 years old, and 46.6 percent of patients were females and 86 percent were white.

Of the patients, 42.6 percent were treated in the ICU, and they stayed there for a median of two days.

The researchers defined low ICU utilization hospitals as those that treated less than 30 percent of patients with NSTEMI in an ICU. Intermediate ICU utilization hospitals treated 30 percent to 70 percent of patients with NSTEMI in an ICU, while high ICU utilization hospitals treated more than 70 percent of patients with NSTEMI in an ICU.

There were no significant differences in hospital or patient characteristics among the low, intermediate or high ICU utilization hospitals, according to the researchers.

Within 30 days of an admission for NSTEMI, 9.2 percent of patients had died, including 8.7 percent at low ICU utilization hospitals, 9.6 percent at intermediate ICU utilization hospitals and 8.7 percent at high ICU hospitals. The median ACTION in-hospital mortality risk score was similar between the hospitals, as well.

The researchers found the same association between hospital ICU utilization and mortality among patients with ACTION risk scores greater than 40, from 30 to 40 and less than 30.

The researchers mentioned a few limitations of the study, including that they could not determine if patients elected to go to the ICU or transferred there after clinical deterioration. They also noted it was an observational study, so they could not infer a causal relationship between ICU utilization and mortality. In addition, the registry did not examine variables such as chest pain or dynamic electrocardiographic changes that could have resulted in an ICU admission. Further, the study only included Medicare patients, who the results might not be generalizable to other patient populations.

“Additional research is needed to identify the optimal strategy of ICU admission in patients with NSTEMI, but more judicious use of ICU admission, with a focus on identifying patients most likely to require ICU-level care, could result in similar outcomes but significant cost savings,” the researchers wrote.