Long-term Survival of Critically Ill Patients Stratified According to Pandemic Triage Categories: A Retrospective Cohort Study

BACKGROUND: The COVID-19 pandemic has led to unprecedented demand for ICUs, 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 the 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: This study analyzed prospectively collected registry data (2007-2018) in 23 ICUs in Victoria, Australia, with probabilistic linkage with death registries. After excluding elective surgery, admissions were stratified according to 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: This study examined 126,687 ICU admissions. After 5 years of follow-up, 1,093 of 3,296 (33%; 95% CI, 32-34) of “low-priority” patients aged ≥ 85 years or with severe chronic illness and 86 of 332 (26%; 95% CI, 24-28) with a SOFA score ≥ 12 were still alive. Sixty-three of 290 (22%; 95% CI, 17-27) of patients in these groups followed up 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 the high-priority patients (28%). Among nonsurvivors, 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.