Table 2.

Key Findings of Studies of Frailty in the ICU

Clinical Finding	Association With Frailty in the ICU
Admission
Indication	On a proportional basis, frailty is associated with more frequent admission to the ICU for acute indications such as acute medical illness or emergency surgery compared to admission following elective surgery.
Severity of illness	Inconsistent results across studies. Patients living with frailty are generally more likely admitted to the ICU, with higher illness severity scores such as APACHE and SOFA.
Advanced directives	Patients living with frailty who are admitted to the ICU are more likely to have orders for limitation of care, such as “do not resuscitate” and “DNI.”
ICU course
Mortality	Frailty is associated with increased mortality in the ICU, particularly in the subset of ICU patients with lower illness severity scores. Multivariable analyses do not consistently demonstrate frailty as an independent predictor of ICU mortality.
Organ supports and complications	Inconsistent results across studies with potential for significant confounding potentially due to orders for limitation of care. General tendency toward increased use of organ supports and increased incidence of ICU complications. Possible less frequent use of invasive mechanical ventilation and more frequent use of noninvasive ventilation, likely attributable to DNI orders.
Length of stay	Inconsistent but larger studies suggest increased LOS in the ICU for patients living with frailty.
Post-ICU course
Mortality	Frailty is associated with increased in-hospital mortality and long-term mortality, performing well as an independent predictor of mortality in multivariable analyses.
Disability	Among survivors of critical illness, frailty is associated with an increased total burden of disability through at least 6 mo.
Nursing home admission	Among those survivors of critical illness who are community dwelling at baseline, frailty is associated with an increased risk of admission to a nursing home following ICU discharge.

A number of relatively consistent differences have been observed between patients living with and without frailty in the ICU. The diversity and inconsistency of implementation of frailty measurement tools suggest that aggregate results may be hard to interpret with regards to specific values and likelihoods, but confirmation across an adequate number of observational trials suggest that frailty confers a number of disadvantages with regards to the clinical course of critical illness.

Abbreviations: APACHE, Acute Physiologic and Chronic Health Evaluation; DNI, do not intubate; ICU, intensive care unit; LOS, length of stay; SOFA, Sequential Organ Failure Assessment.