Overreliance on the ICU for cardiac patients leads to worse outcomes, study finds. "We still have an open question of what to use the ICU for," says one researcher.
Hospitals that rely the most heavily on the ICU to treat their heart patients had higher 30-day mortality rates for those patients than hospitals with the lowest ICU heart admissions, researchers have found.
Data shows that heart attack patients treated in high-ICU hospitals were 6% more likely to die within 30 days of discharge than patients admitted to low-ICU hospitals, and the difference was about 8% for heart failure patients.
The study, published online in the journal CHEST, is also a reminder that it's often unclear when and why patients should actually be admitted to the ICU, and that usage of ICUs varies widely from hospital to hospital.
Researchers at the University of Michigan Medical School examined Medicare records from more than 570,000 hospital stays that took place in 2010.
More than 150,000 hospitalizations for acute myocardial infarction at nearly 1,700 hospitals were identified, and 46% of them included care in an ICU. More than 400,000 hospitalizations were for heart failure at 2,199 hospitals, and 16% of them included an ICU stay.
The researchers used the federal government's Hospital Compare website to examine how well each hospital did at providing high-quality care, and what percentage of their patients died or ended up back in the hospital within a month of the hospital stay. They divided all the hospitals into five groups, from lowest ICU use to highest.
Hospitals in the lowest quintile had ICU admission rates of less than 29% for acute myocardial infarction (AMI) or less than 8% for heart failure. However hospitals in the top quintile had ICU admission rates of greater than 61% for AMI or greater than 24% for heart failure. Hospitals in the highest quintile had higher process measure failure rates for some but not all process measures.
There were no differences in the odds of being hospitalized again, or in total spending on care.
More ICU Use, Poorer Quality Care
Researchers also found evidence of lower quality of care among hospitals that used the ICU more often.
The hospitals with high ICU use were less likely to give heart attack patients aspirin when they arrived. They were also less likely to give other drugs that are known to improve outcomes after heart attacks.
In heart failure cases, the hospitals with high ICU were less likely to give some important medications, perform key tests of heart function, and counsel patients to stop smoking.
The authors also found that hospitals with the highest percentage of patients admitted to the ICU tended to be those with the smallest numbers of heart attack and heart failure patients over all, suggesting a lack of institutional familiarity with these conditions.
These were also more likely to be for-profit hospitals. Patients treated in them were more likely to be from low-income ZIP codes.
According to the authors, the study results suggest a need for more standardization in deciding which patients need an ICU, as well as a greater focus on quality of care in hospitals with the highest ICU use.
"In this country, we still have an open question of what to use the ICU for, and when, and very little evidence to guide physicians," first author Thomas Valley, MD, MSc, said in a statement.
"Is it for those who were already sick and got worse, or is it a place to send people proactively when we think they might get sicker? And the answer can vary on different days, or based on how many beds are available right then. We hope to build a body of evidence about how to use this valuable resource in the most effective way."
Co-author Michael Sjoding, MD, MSc, previously led a study that showed a similar pattern among patients hospitalized for pneumonia. The hospitals that sent the most such patients to the ICU had the lowest quality performance on that condition, too.
"These studies suggest that hospitals using the ICU frequently could be targets for improvement. If we find out why hospitals are using ICU beds more often for these patients, we could intervene to improve care overall," Valley said.