in their retrospective cohort analysis , bagshaw and colleagues   report the results of 120,123 intensive care unit ( icu ) admissions in australia and new zealand between january 2000 and december 2005 . the robust database they explored allowed the determination of important clinical characteristics , ultimate hospital dispositions of these patients , and predictors of survival . the proportion of icu patients 80 years or older increased over the 6 years by an annual average of 5.6% ; interestingly , higher than the increase in this segment of the general australian and new zealand population . patients 80 years or older were more seriously ill , with higher age - adjusted acute physiology and chronic health evaluation ( apache ) scores on admission , and had longer lengths of stay if they survived the admission . these older patients had the highest mortality of any age group , and were also more likely to be discharged to a rehabilitation or long - term care facility , as opposed to living independently in the community . several factors increased the odds of death among patients 80 years or older , including admission from a chronic care facility , a non - surgical admission , a higher age - adjusted apache score , the need for mechanical ventilation , and acute kidney injury . although these results are not surprising , they represent one of the few large outcome studies of elderly patients admitted to icu . it is conceivable that patients who live longer than 80 years already be ' self selected ' as more likely to survive critical illness than some younger patients . for instance , somme and colleagues   performed a single - centre cohort study in which they found that among the population aged 75 years or older , increased age did not correlate with worse survival . in fact , the cohort aged 75 to 79 years had a higher mortality than the group aged 80 to 84 years . although not borne out by the survival statistics in the current much larger study by bagshaw and colleagues , it is interesting to note that in this study , the proportions of patients with multiple comorbidities in the 65 to 79 and 80 years and above groups were not significantly different . when examining outcomes of patients admitted to icu , there very likely is a degree of selection bias not only by patients , but also by health care professionals who have offered icu admission to such patients , presumably believing that there may be beneficial effects from aggressive icu care for this subset of the octogenarian population . chelluri and colleagues   performed a prospective comparison of critically ill patients aged 75 years or older , in comparison to patients younger than 75 years , and found that the admission apache score predicted outcome better than age alone . this is not surprising since the apache score , which includes age as a component , is validated to do exactly this on a population - wide basis . similar results were reported by de rooij and colleagues , who performed a relatively small retrospective cohort study , which showed that the best predictor of survival in patients 80 years and older was severity of illness . a single - centre cohort study by boumendil and colleagues   also found that long - term survival in patients 80 years and older was related more to their underlying condition and functional status rather than age . the inability to examine data from elderly patients considered for , but not admitted to , icu makes it difficult to draw firm conclusions about decision - making prior to admission . it is well established that age is an independent predictor of a ' not for resuscitation ' order [ 6 - 8 ] , and scenario - based studies of physician decision - making also identify age as an independent predictor of denial of admission to icu [ 9 - 11 ] . these factors mean that there is likely a substantial pre - selection of the elderly population admitted to icu , either on a patient or physician level . it is unclear , however , whether elderly patients are being ' over- or under - admitted ' to icu . in a unique study design , garrouste - orgeas and colleagues   examined a cohort of patients 80 years or older who were assessed for icu admission . over two - thirds were denied admission ; factors associated with refusal were non - surgical status , age over 85 , and no available beds in the icu . prior research has taught us that many elderly patients do not want aggressive interventions , with only regard for life - saving potential , but instead prefer an approach emphasizing relief of symptoms [ 13 - 15 ] . future larger - scale research may better clarify not only what happens once admitted to icu , but the outcomes of patients who choose not to be admitted , or who are declined admission to icu . bagshaw and colleagues highlight the growing challenges in light of uncertain outcomes that are faced by patients , their families , and intensivists as the elderly segment of our populations expand . it is clear that decision - making based on age alone is inadequate , and would not stem from an evidence - based perspective of outcomes . through this and other outcomes - based research , we have increasing knowledge with which to guide patients and families in decision - making about care during critical and potentially end - of - life illness .
the demographic shift in the age of most industrialized countries ' populations is profoundly impacting all areas of healthcare , perhaps nowhere more so than critical care . 
 as the proportion of elderly patients increases , so to will our consideration for admission of elderly patients to the intensive care unit ( icu ) . whether explicitly acknowledged or not , intensivists routinely debate ( both inwardly and outwardly ) the benefit , utility , and patient - focused dignity of admitting very elderly patients to the icu . despite the apparent increase in demand for , and provision of critical care services to , the elderly , there are few data on the outcomes from these admissions , and how one might predict which elderly patients are most likely to derive benefit from the invasive and resource - intensive services provided in modern icus .