Characteristics and Outcomes of Very Elderly Patients Admitted to Intensive Care: A Retrospective Multicenter Cohort Analysis

Abstract

Objectives: To characterize and compare trends in ICU admission, hospital outcomes, and resource utilization for critically ill very elderly patients (≥ 80 yr old) compared with the younger cohort (16-79 yr old).

Design: A retrospective multicenter cohort study.

Setting: One-hundred ninety-four ICUs contributing data to the Australian and New Zealand Intensive Care Society Centre for Outcome and Resource Evaluation Adult Patient Database between January 2006 and December 2018.

Patients: Adult (≥ 16 yr) patients admitted to Australian and New Zealand ICUs.

Interventions: None.

Measurements and main results: Very elderly patients with a mean ± sd age of 84.8 ± 3.7 years accounted for 14.8% (232,582/1,568,959) of all adult ICU admissions. They had higher comorbid disease burden and illness severity scores compared with the younger cohort. Hospital (15.4% vs 7.8%, p < 0.001) and ICU mortality (8.5% vs 5.2%, p < 0.001) were higher in the very elderly. They stayed fewer days in ICU, but longer in hospital and had more ICU readmissions. Among survivors, a lower proportion of very elderly was discharged home (65.2% vs 82.4%, p < 0.001), and a higher proportion was discharged to chronic care/nursing home facilities (20.1% vs 7.8%, p < 0.001). Although there was no change in the proportion of very elderly ICU admissions over the study period, they showed a greater decline in risk-adjusted mortality (6.3% [95% CI, 5.9%-6.7%] vs 4.0% [95% CI, 3.7%-4.2%] relative reduction per year, p < 0.001) compared with the younger cohort. The mortality of very elderly unplanned ICU admissions improved faster than the younger cohort ( p < 0.001), whereas improvements in mortality among elective surgical ICU admissions were similar in both groups ( p = 0.45).

Conclusions: The proportion of ICU admissions greater than or equal to 80 years old did not change over the 13-year study period. Although their mortality was higher, they showed improved survivorship over time, especially in the unplanned ICU admission subgroup. A higher proportion of survivors were discharged to chronic care facilities.