Is ICU Care Appropriate for the Very Elderly?
Abstract & Commentary
By David J. Pierson, MD, Editor, Professor, Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, is Editor for Critical Care Alert.
Synopsis: Very elderly patients survive critical illness less often than younger patients and have worse functional outcomes, although the findings of existing studies are inadequate for specific predictions and some patients do have good outcomes. Prognostic models such as APACHE are poorly suited for use in very elderly patients.
Source: de Rooij SE, et al. Factors that predict outcome of intensive care treatment in very elderly patients: a review. Crit Care. 2005;4:R307-R314.
Investigators at the university of amsterdam performed an extensive review of articles, retrieved via Medline, that reported ICU outcomes in very elderly patients. Their goals were to examine the predictors of mortality, to evaluate the appropriateness of existing models such as the APACHE scores in predicting outcomes, and to assess existing data relating to patient preferences for ICU care among such patients. They considered patients aged 80 years and older to be "very elderly," although studies in the literature varied as to how this was defined.
Twelve studies (9 prospective and 3 retrospective) were identified that were based on large databases and deemed appropriate for inclusion in the review, although these were so sufficiently heterogeneous that formal meta-analysis could not be performed. In consequence, the authors discussed the findings in narrative form under several categories. That mortality increases with increasing age was a consistent finding, although the rates and magnitude of age association varied among studies. It was clear that the reason for ICU admission exerts a strong influence on outcome, although an effect of age per se could not be consistently determined.
Although very elderly patients commonly have more comorbidities than younger patients, the influence of comorbidities has not been specifically studied and no fixed conclusions could be drawn. Functional and cognitive status, while seemingly very important as determinants of overall outcomes in very elderly patients, similarly could not be quantitated as specific predictors. The reviewed studies shed little light on patient preferences in the very elderly in contrast to those in younger patients. However, in the SUPPORT Study,1 physicians were more likely to believe incorrectly that older patients did not want life-sustaining treatments: 79% for patients over 80 years, as compared to 36% for patients younger than 50 years.
While, in general, ICU patient population prognostic models such as SAPS II, MPM II, APACHE II, and APACHE III are predictive of survival, these models are not calibrated for use in very elderly patients, and they do not take into consideration a number of factors that are major determinants of outcome in such individuals. The authors conclude that a new model is needed for predicting outcome in very elderly ICU patients.
Commentary
Outcomes of critical illness are not as good in elderly patients as in those who are younger.2 In the SUPPORT study,1 the risk of death increased by 1% per year of age among patients 18 to 70 years old, and by 2% per year for patients older than 70. The likelihood of dying appears to go up the older the patient is, as shown in the Figure, taken from the Dutch National Intensive Care Evaluation (NICE) database.3 Patients aged 85 and older had substantially higher in-hospital mortality than those aged 75-84, who in turn survived less well than patients younger than 75. In a study of more than 40,000 ICU patients requiring mechanical ventilation in one state,4 70% of patients aged 85 or older died, as compared to 32% of patients younger than age 30.
These things are understood by everyone who works in an ICU. Even within a particular diagnostic category or for a given set of comorbidities, very old patients are more likely to do poorly than those who are younger. However, currently available studies are insufficient to provide clinicians with specific guidance as to which elderly patients do or do not stand to benefit from ICU care. Most studies that report what happened to a particular group of ICU patients suffer from unknown selection bias: how was the decision made to admit a particular individual to the ICU in the first place? The importance of this is borne out by the Dutch NICE database,3 as discussed by de Rooij et al. In the population of ICU patients older than age 80, mortality was 16.5% among those who had undergone cardiac surgery as compared to 46% in the others. Clearly, patients more likely to survive were somehow being selected for cardiac surgery.
The bottom line appears to be that age by itself is a general predictor of a poor outcome from critical illness, but probably not as important a predictor as other factors that are similar to those in other patients. The appropriateness of ICU care needs to be determined in the context of the cause of critical illness, the nature and severity of coexisting conditions, baseline functional status, and patient preferences—in very elderly patients just as for everyone else.
References
- Hamel MB, et al. Patient age and decisions to withhold life-sustaining treatments from seriously ill, hospitalized adults. SUPPORT Investigators. Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatment. Ann Intern Med. 1999;130:116-125.
- Wood KA, Ely EW. What does it mean to be critically ill and elderly? Curr Opin Crit Care. 2003;9:316-320.
- de Jonge E, et al. Intensive care medicine in the Netherlands, 1997-2001. 1. Patient population and treatment outcome [in Dutch]. Ned Tijdschr Geneeskd. 2003;147:1013-1017.
- Cohen IL, Lambrinos J. Investigating the impact of age on outcome of mechanical ventilation using a population of 41,848 patients from a statewide database. Chest. 1995;107:1673-1680.
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