Limitation of Life-Sustaining Care in the Critically Ill: A Systematic Review of the Literature
When life-sustaining treatments (LST) are no longer effective or consistent with patient preferences, limitations may be set so that LSTs are withdrawn or withheld from the patient. Many studies have examined the frequency of limitations of LST in intensive care unit (ICU) settings in the past 30 years. This systematic review describes variation and patient characteristics associated with limitations of LST in critically ill patients in all types of ICUs in the United States. A comprehensive search of the literature was performed by a medical librarian between December 2014 and April 2017. A total of 1,882 unique titles and abstracts were reviewed, 113 were selected for article review, and 36 studies were fully reviewed. Patient factors associated with an increased likelihood of limiting LST included white race, older age, female sex, poor preadmission functional status, multiple comorbidities, and worse illness severity score. Based on several large, multicenter studies, there was a trend toward a higher frequency of limitation of LST over time. However, there is large variability between ICUs in the proportion of patients with limitations and on the proportion of deaths preceded by a limitation. Increases in the frequency of limitations of LST over time suggests changing attitudes about aggressive end-of-life-care. Limitations are more common for patients with worse premorbid health and greater ICU illness severity. While some differences in the frequency of limitations of LST may be explained by personal factors such as race, there is unexplained wide variability between units.
© 2019 Society of Hospital Medicine
RESULTS
Study Selection
A total of 2,460 references were identified, and after removal of 578 duplicates, 1,882 unique titles and abstracts were reviewed. One hundred thirteen titles met the inclusion criteria. After review of complete texts, 83 were excluded based on the above criteria (Appendix). This led to a final number of 36 studies included for analysis.
Fifteen articles were prospective, observational studies. The rest were retrospective analyses of patient-level data. Seven were large, multicenter studies with greater than 20 centers involved (including Project IMPACT); six such studies included medical and surgical patients. The remaining large, multicenter study examined a surgical trauma cohort.
Fifteen of the studies addressed DNR as a limitation and 25 addressed other limitations such as withdrawing or withholding LST (several addressed both DNR and another limitation). Nine studies enrolled only patients who had died and the remaining 27 enrolled all ICU admissions.
Historical Trends
Examination of the three studies that looked at >20 regionally diverse ICUs revealed a trend over time toward increased limitation prior to death (Figure). Jayes looked at the number of DNR orders preceding death from 1979 to 1980 then compared that to a cohort from 1988 to 1990; Prendergast included withholding/withdrawing of LST prior to death from 1994 to 1995;and Quill used the IMPACT database to examine limitations prior to death from 2001 to 2009.3-5
Effect of Unit Specialty
Twelve studies were mixed (surgical/medical or medical/neuro) ICUs, 11 were medical/cardiac units, five were neurologic units, and six were surgical/trauma units only. Two studies did not report unit specialty. Four studies that compared surgical and medical ICUs found that surgical patients were more likely to die with full intervention.4-7 In all of these studies, medical patients were more likely to have limitations of LST preceding death. Quill, et al. further detailed that emergency surgery was more likely to be associated with limitation than elective surgery.5
Patient Factors
In 15 studies, older age was associated with an increased likelihood of limitations on LST.3,5-18 In one study, advanced age was associated with early versus late withdrawal.19 Poor performance status and multiple medical comorbidities were also associated with limitations of LST. The largest population-based study by Quill et al. found that being fully dependent on others upon admission to the ICU was associated with an increased likelihood of limiting LST.5 Sise et al. found, in an analysis performed over 10 years in one trauma center, that increased age, comorbidities, and a fall as the reason for trauma admission were associated with limitation of LST.9 Salottolo et al. found that if the reason for trauma admission was a fall, there was an increased odds ratio of DNR status.18 Many studies found that having medical comorbidities prior to admission was associated with increased likelihood of limiting LST in both medical and surgical patients.3,7,9,13,15,18
Five studies found a statistically significant difference between women and men in the likelihood of limitation of LST,3,5,9,14,16 and another study reported that women who were trauma patients had an increased odds ratio of changing to DNR code status.18 Only one study found that males were associated with an increased likelihood of limiting aggressive treatment.20
White race was associated with increased limitation of LST in nine studies.4,5,10,11,14-16,21,22 One study in neurocritical care patients found that both white and Hispanic races were correlated with a higher likelihood of limitations.23 Muni et al. found that nonwhite patients had a statistically significantly lower likelihood of having comfort measures and DNR orders written prior to death, but discussion of prognosis was more likely to be documented in nonwhite patients.21
In summary, white race, female gender, and older age were the most frequent factors associated with a higher likelihood of limiting LST.
