Mechanical Ventilation During ICU Stay Associated with High
NEW YORK (March 2, 2010) – Although there has been a decrease in the risk of in-hospital death for patients who receive intensive care in the United States, a new analysis of Medicare data by NewYork-Presbyterian Hospital/Columbia University Medical Center researchers and colleagues indicates that elderly patients who are hospitalized in an intensive care unit (ICU) and survive to be discharged from the hospital have a high rate of death in the following three years.
In particular, patients who receive mechanical ventilation have a substantially increased rate of death compared with both hospital and general population controls in the first several months after hospital discharge, according to a study in the March 3, 2010, issue of JAMA.
“Patients older than 65 years now make up more than half of all ICU admissions,” says Hannah Wunsch, M.D., M.Sc., assistant professor of anesthesiology at Columbia University College of Physicians and Surgeons and an anesthesiologist at NewYork-Presbyterian Hospital/Columbia University Medical Center. “Information is needed to understand the patterns of mortality, morbidity, and health care resource use in the months and years that follow critical illness to allow for better targeting of follow-up care.”
Dr. Wunsch and colleagues examined the 3-year outcomes and health care resource use of ICU survivors, and identified subgroups of patients and periods in which patients are at highest risk of death, using a 5 percent sample of Medicare beneficiaries older than 65 years. A random half of all patients were selected who received intensive care and survived to hospital discharge in 2003 with 3-year follow-up through 2006. From the other half of the sample, 2 matched control groups were generated: hospitalized patients who survived to discharge (hospital controls) and the general population (general controls), individually matched on age, sex, race, and whether they had surgery (for hospital controls).
“What’s unique about this study is our ability to really compare ICU survivors with control groups to gain an understanding of the impact of critical illness. The traditional approach has been to look at cohorts of ICU patients alone, which doesn’t allow you to really say anything about how they are doing,” Dr. Wunsch said. “The fact that we could match ICU survivors to people in the general Medicare population and follow them for three years allowed us to really quantify the differences in risk for these elderly patients.”
In the data analyzed for the study, 35,308 ICU patients survived to hospital discharge. The ICU survivors had 3-year mortality (39.5 percent) that was a little higher than hospital controls (34.5 percent) and much higher than general controls (14.9 percent). The ICU survivors who did not receive mechanical ventilation had minimal increased risk compared with hospital controls (3-year mortality, 38.3 percent vs. 34.6 percent).
“However, mortality for those who received mechanical ventilation was substantially higher than for the corresponding hospital controls (3-year mortality: 57.6 percent vs. 32.8 percent, respectively). This difference was primarily due to mortality during the first 2 quarters following hospital discharge (6-month mortality: 30.1 percent for ICU survivors vs. 9.6 percent for hospital controls),” the authors write.
Many ICU survivors were discharged to skilled care facilities (33.0), as were hospital controls (26.4 percent). The need for further skilled care also was associated with high 6-month mortality (24.1 percent for ICU survivors and hospital controls discharged to a skilled care facility vs. 7.5 percent for ICU survivors and hospital controls discharged home).
“These findings highlight the need for a much more detailed understanding of the long-term care needs of these patients,” the authors conclude.
“The magnitude of the post-discharge use of skilled care facilities for both ICU survivors and hospital controls and the high long-term mortality for all of these patients call into question what is happening after discharge,” says Dr. Wunsch. “It is possible that discharge to skilled care facilities is merely a marker for higher severity of illness with appropriate delivery of care, or these patients could have been discharged prematurely from acute care hospitals, and needed a higher level of care than they received. Finally, it is possible that some of these patients could have had better outcomes if discharged home, but were not able to be sent there due to lack of sufficient support from family or friends to act as caregivers. There are well over a million elderly ICU survivors each year in the US, and clearly much more research is needed to understand how we can deliver the best care for these people after critical illness.”
Other authors on the paper include Carmen Guerra, MPH, Guohua Li, M.D., MPH, both also from Columbia, as well as Derek C. Angus, M.D., MPH, at the University of Pittsburgh, among others.
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