The epidemiology of critical illness in the elderly.

A substantial proportion of patients admitted to intensive care units (ICUs) are elderly patients. Based upon population growth, patient preference, and current physician practice, the number of elderly patients who receive critical care services is likely to increase substantially over the next 10 to 20 years. Numerous studies have shown that survival from critical illness is lower in elderly patients; however, after adjusting for factors such as illness severity, comorbid diseases, and functional status, chronologic age accounts for very little explanatory power for survival from critical illness. Elderly survivors of critical illness often have significant functional limitations, but their perceived quality of life is usually better than that of younger survivors of critical illness. Elderly patients frequently receive less aggressive care in the ICU and probably consume a lower relative proportion of ICU resources than younger patients. However, this does not necessarily result in worse outcomes.