Long-term survival of critically ill patients stratified by pandemic triage categories: a retrospective cohort study

Darvall, Jai N.; Bellomo, Rinaldo; Bailey, Michael; Anstey, James; Pilcher, David

Background The COVID-19 pandemic has led to unprecedented demand for ICU, with the need to triage admissions along with the development of ICU triage criteria. However, how these criteria relate to outcomes in patients already admitted to ICU is unknown, as is the incremental ICU capacity that triage of these patients might create given existing admission practices. Research Question What is the short and long-term survival of low vs. high priority patients for ICU admission according to current pandemic triage criteria? Study Design and Methods: We analysed prospectively collected registry data (2007-2018) in 23 ICUs in Victoria, Australia, with probabilistic linkage with death registries. After excluding elective surgery, we stratified admissions by existing ICU triage protocol prioritization as low (age >85 years, or severe chronic illness, or Sequential Organ Failure Assessment [SOFA] score = 0 or ≥12), medium (SOFA score 8-11) or high (SOFA score 1-7) priority. The primary outcome was long-term survival. Secondary outcomes were in-hospital mortality, ICU length of stay (LOS) and bed-day usage. Results We studied 126,687 ICU admissions. After five-years of follow up, 1093/3296 (33%, 95%CI 32%-34%) of “low-priority” patients aged >85 years or with severe chronic illness, and 86/332 (26%, 95%CI 24%-28%) with a SOFA score ≥12 were still alive. 63/290 [22%, 95% CI 17%-27%] of patients in these groups followed for 10 years were still alive. Together, low priority patients accounted for 27% of all ICU bed-days, and had lower in-hospital mortality (22%) than than high priority patients (28%). Among non-survivors, low-priority admissions had shorter ICU LOS than medium or high-priority admissions. Interpretation Current SOFA-score or age or severe comorbidity-based ICU pandemic triage protocols exclude patients with a close to 80% hospital survival, a >30% five-year survival and 27% of ICU bed-day use. These findings imply the need for stronger evidence-based ICU triage protocols.