By Linda Chlan, PhD, RN, FAAN
Dean’s Distinguished Professor of Symptom Management Research, The Ohio State University, College of Nursing
Dr. Chlan reports no financial relationships relevant to this field of study.
SYNOPSIS: Admission to an ICU results in functional decline and increased mortality in older adults, particularly in those severely disabled prior to critical illness or injury.
SOURCE: Ferrante L, et al. Functional trajectories among older persons before and after critical illness. JAMA Intern Med 2015 February 9 [Epub ahead of print].
The impact of an older person’s functional status prior to experiencing hospitalization for a critical illness is difficult to determine. Given that ICU admission is generally an unplanned event, obtaining prospective evaluations of function prior to a critical illness or injury is almost impossible. Most evidence to date has utilized proxy reports for a patient’s functional status to determine what, if any, pre-ICU disability may have on an older adult’s outcomes after hospitalization for a critical illness or injury.
The study by Ferrante and colleagues had the opportunity to access a rich longitudinal dataset containing 754 community-dwelling persons age 70 years and older in the New Haven, CT, area. Participants in the parent study had no disabilities initially and had in-home assessments at 18-month intervals for a total of 162 months, followed by monthly telephone interviews through December 31, 2012. In total, participants were followed for 15 years. These monthly interviews queried participants for impairments in 13 disabilities including basic, instrumental, and mobility activities. Medicare claims data were used to determine if any of the participants experienced an ICU admission. If so, ICU data were then obtained for length of ICU stay, receipt of mechanical ventilation, diagnosis of shock, specific ICU service (medical, surgical, neurological, cardiac), and discharge diagnosis. Modeling techniques were used to determine participants’ functional trajectory in the year before and year after ICU admission. A number of important clinical covariates (age, sex, education, race, chronic conditions, mechanical ventilation, ICU length of stay, cognitive impairment, etc.) were then modeled to determine the trajectory of participants during the post-ICU period, including 30-day and 1-year mortality.
Of the participants in the parent study, 291 (38.6%) were admitted to an ICU. A majority of those patients were female (58%), non-Hispanic whites (88.7%) with a mean age of 83.7 years. Most patients were admitted to a medical or general ICU, followed by surgical or cardiothoracic, neurosurgical ICU, or burn. Functional trajectories were identified as minimal disability (20.8%), mild-to-moderate disability (28.1%), and severe disability (51.1%). A full 53.4% of the participants had functional decline or experienced early death after ICU admission. For those older patients with minimal disability prior to ICU admission, approximately 25% developed serious disability or early death after hospitalization in the ICU. Of participants with mild-to moderate disability, 39.5% developed serious disability and 25% early death. Lastly, a full one-third of those participants admitted to a critical care unit with severe pre-ICU disability experienced early death. Approximately 24% of the participants died in the ICU. Overall, the 30-day mortality rate was 21%, most significantly influenced by the receipt of mechanical ventilation, diagnosis of shock, and cognitive impairment. Whereas pre-ICU functional trajectory was not significantly associated with 30-day mortality, mild-moderate and severe pre-ICU functional trajectories were associated with more than double and triple the risk of death within 1 year of ICU admission compared to minimal disability. Overall 1-year mortality was 43%, and it was also influenced by ICU length of stay, receipt of mechanical ventilation, and diagnosis of shock.
The study by Ferrante and colleagues reports the influence of functional status prior to ICU admission on outcomes in older adults. The effect of pre-ICU functional trajectories is independent of and comparable to use of mechanical ventilation and diagnosis of shock on 1-year mortality outcomes in older adults. Even those older adults with minimal or mild disability one year prior to a critical illness or injury experienced declines in functional status and increased mortality after ICU admission. Unfortunately, those older adults with greater functional status impairment in the year prior to ICU admission had worse outcomes with higher 30-day and 1-year mortality rates.
This study was unique in that functional status was obtained prospectively in a cohort of older adults followed over a number of years, overcoming many limitations of previous investigations in the area of post-ICU outcomes that relied solely on proxy reports of functional status. As older adults are living longer, they may be at risk for admission to a critical care unit. Investigations are urgently needed to design and test innovative interventions to prevent further decline in functional abilities, particularly in those patients with lengthy ICU stays and receipt of mechanical ventilatory support. Efforts are needed to ensure older adults can maintain their functional abilities and not decline after a critical illness or injury, which has significant implications for ICU care processes.