Admission to an ICU associated with lower 30-day mortality in STEMI patients

The retrospective study focused on patients who had marginal need for an ICU after ST-elevation myocardial infarction (STEMI) but were admitted because they were treated at a hospital with a high ICU admission rate.

Admission to an ICU was associated with lower mortality among patients who had ST-elevation myocardial infarction (STEMI) and marginal need for intensive care, a recent study found.

The retrospective cohort study included 109,375 Medicare beneficiaries (ages 65 years or older) admitted with STEMI to 1,727 acute care hospitals between January 2014 and October 2015. Researchers assessed the rate at which hospitals admitted such patients to the ICU; the hospitals in the top quarter of ICU admission rates admitted 85% or more of their STEMI patients to an ICU. Results were published by The BMJ on June 4.

Using an instrumental variable analysis, researchers identified patients whose proximity to a hospital in the top quarter of ICU admission rates appeared to determine whether they were admitted to an ICU. Among those patients, being admitted to an ICU was associated with lower 30-day mortality compared to being admitted to a general, telemetry, or intermediate care ward (absolute decrease, 6.1 percentage points; 95% CI, −11.9 to −0.3 percentage points). The study also looked at patients with non-ST-elevation MI (NSTEMI) as a comparison population, since routine ICU use has been shown not to improve their outcomes, and found that ICU admission for NSTEMI was not associated with reduced mortality (absolute increase, 1.3 percentage points; 95% CI, −0.9 to 3.4 percentage points).

“Contrary to the prespecified hypothesis, we found that ICU care may be underused for certain patients with STEMI,” the authors wrote. They noted that the results apply only to patients without obvious indications for or against ICU care and that the study did identify some population-level characteristics of such “marginal” patients, including age older than 85 years and no organ failure.

The results do not show what about the ICU was particularly beneficial to the patients, but the authors speculated that it could be enhanced nursing care, better management of noncardiac conditions, timely access to certain treatments, or more effective protocols. “Thus, the results of this study may have more to do with limitations of non-ICU care rather than the direct benefits of ICU care,” the authors wrote. Limitations of the study include the risk of residual confounding, the treatment of ICUs and coronary care units as equivalent, and the inclusion of only patients 65 years of age and older.

“Conventional wisdom in the US suggests that ICU care is generally overused and that efforts must be made to reduce the number of patients receiving ICU care. However, this study, in combination with others, indicates instead that ICU care may often be misdirected, with some patients experiencing underuse while others experience overuse,” the authors concluded.