Medicare fee-for-service beneficiaries with an exacerbation of heart failure or acute MI who were admitted to the intensive care unit (ICU) had similar 30-day mortality rates compared with those who were not admitted to the ICU, according to a retrospective cohort study.

ICU admissions were also associated with significantly greater hospital costs for heart failure and acute MI.

Lead researcher Thomas S. Valley, MD, MSc, of the University of Michigan, and colleagues published their results online in the Annals of the American Thoracic Society on Feb. 17.

“Our results highlight that there is a large group of patients who doctors have trouble figuring out whether or not the ICU will help them or not,” Valley said in a news release. “We found that the ICU may not always be the answer. Now, we need to help doctors decide who needs the ICU and who doesn’t.”

Although patients with acute MI, heart failure or chronic obstructive pulmonary disease (COPD) are frequently admitted to the ICU, the researchers noted that hospitals had significant variations in admission rates.

This study analyzed all acute care hospitalizations from 2010 to 2012 for acute MI, heart failure and COPD among fee-for-service Medicare beneficiaries who were age 65 or older.

The researchers identified 604,894 patients with COPD exacerbation, 626,174 patients with heart failure exacerbation and 324,729 patients with acute MI. They mentioned that 20.0 percent of patients with COPD, 24.7 percent of patients with heart failure and 64.9 percent of patients with acute MI were admitted to the ICU.

Patients admitted to the ICU were more likely to be between 65 and 75 years old, male, have a higher number of failed organs and receive mechanical ventilation or cardiac catheterization.

After adjusting for patient and hospital characteristics, ICU admission was associated with higher 30-day mortality for patients with COPD and heart failure and lower mortality for patients with acute MI. ICU admission was also associated with higher costs for all three conditions.

Meanwhile, instrumental variable analyses found that there were no significant differences in 30-day mortality associated with ICU admission for any of the three conditions. ICU admission was associated with significantly higher costs for heart failure (an increase of $2,608) and acute MI (an increase of $4,922), but there was no difference in the costs for COPD.

“These findings suggest that the ICU may be overused for some COPD, [heart failure], or [acute MI] patients with an uncertain indication for intensive care, and opportunities exist to decrease healthcare costs by reducing ICU admissions for certain patients,” the researchers wrote.

The researchers mentioned the finding only apply to marginal patients, which they defined as those patients admitted to the ICU solely because of their proximity to a high ICU hospital. They noted that the results should apply to patients for whom ICU admission is not clearly indicated and patients who have obvious needs for the ICU such as those who require mechanical ventilation or vasopressor support.

They also cited a few limitations of the study, including that they relied on administrative data, which could have led them to under-identify or improperly identify patients. The study also might have been subject to unmeasured confounding, and the results might not be generalizable to people who do not have Medicare fee-for-service coverage.

In addition, they did not have information on the reason for ICU admission and the timing of ICU admission within a hospitalization. Further, the costs only related to hospital charges and did not include physician, facility or outpatient payments related to the hospitalization.

“These findings suggest that some COPD, [heart failure], or [acute MI] patients without obvious ICU indications may be reasonably cared for in either the ICU or the general ward,” the researchers wrote. “Identifying these patients who do not benefit from ICU admission could reduce costs while improving healthcare efficiency.”