Prevalence and long-term outcomes of patients with life-limiting illness admitted to intensive care units in Australia and New Zealand

Abstract

Objective

Determine the prevalence and outcomes of patients with life-limiting illness (LLI) admitted to Australian and New Zealand Intensive Care Units (ICUs).

Design, setting, participants

Retrospective registry-linked observational cohort study of all adults admitted to Australian and New Zealand ICUs from 1st January 2018 until 31st December 2020 (New Zealand) and 31st March 2022 (Australia), recorded in the Australian and New Zealand Intensive Care Society Adult Patient Database.

Main outcome measures

The primary outcome was 1-year mortality. Secondary outcomes included ICU and hospital mortality, ICU and hospital length of stay, and 4-year survival.

Results

A total of 566,260 patients were included, of whom 129,613 (22.9%) had one or more LLI. Mortality at one year was 28.1% in those with LLI and 10.4% in those without LLI (p < 0.001). Mortality in intensive care (6.8% v 3.4%, p < 0.001), hospital (11.8% v 5.0%, p < 0.001), and at two (36.6% v 14.1%, p < 0.001), three (43.7% v 17.7%, p < 0.001) and four (55.6% v 24.5%, p < 0.001) years were all higher in the cohort of patients with LLI. Patients with LLI had a longer ICU (1.9 [0.9, 3.7] v 1.6 [0.9, 2.9] days, p < 0.001) and hospital length of stay (8.8 [49,16.0] v 7.2 [3.9, 12.9] days, p < 0.001), and were more commonly readmitted to ICU during the same hospitalisation than patients without LLI (5.2% v 3.7%, p < 0.001). After multivariate analysis the LLI with the strongest adverse effect on survival was frailty (HR 2.08, 95% CI 2.03 to 2.12, p < 0.001), followed by the presence of metastatic cancer (HR 1.97, 95% CI 1.92 to 2.02, p < 0.001), and chronic liver disease (HR 1.65, 95% CI 1.65 to 1.71, p < 0.001).

Conclusion

Patients with LLI account for almost a quarter of ICU admissions in Australia and New Zealand, require prolonged ICU and hospital care, and have high mortality in subsequent years. This knowledge should be used to identify this vulnerable cohort of patients, and to ensure that treatment is aligned to each patient's values and realistic goals.