Routine frailty screening in critical illness- a population-based cohort study in Australia and New Zealand.

Abstract

Frailty is associated with poor outcomes in critical illness. However, it is unclear whether frailty screening on admission to ICU can be routinely conducted at the population level and whether it has prognostic importance. Can population-scale frailty screening with the Clinical Frailty Scale (CFS) be implemented for critically ill adults in Australia and New Zealand (ANZ), and identify patients at risk of negative outcomes? We conducted a binational prospective cohort study of critically ill adult patients admitted between 1/7/2018 and 30/6/2020 in 175 ICUs in ANZ. We classified frailty with the CFS, on admission to ICU. Primary outcome was in-hospital mortality, secondary outcomes were length of stay, discharge destination, complications (delirium, pressure injury), and duration of survival. We included 234 568 critically ill patients; 45245 (19%) were diagnosed as living with frailty prior to ICU admission. Patients with vs. without frailty had higher in-hospital mortality (16% vs. 5%, p<0.001), delirium (10% vs. 4%, p<0.001), longer length of stay in ICU and hospital, and increased new chronic care discharge (3% vs. 1%, p<0.001), with worse outcomes associated with increasing CFS category. Of patients with very severe frailty (CFS=8), 39% died in-hospital vs. 2% of very fit (CFS=1) patients (multivariable categorical CFS=8 [ref=1] OR [95% CI] = 7.83 [6.39-9.59], p<0.001). After adjustment for illness severity, frailty remained highly significantly predictive of mortality, including among patients aged <50 years, with improvement in the AUROC (95% CI) of the Acute Physiology and Chronic Health Evaluation (APACHE) III-j score to 0.882 (0.879-0.885) from 0.868 (0.866-0.871) with the addition of frailty (p<0.001). Large scale population screening for frailty degree in critical illness was possible and prognostically important, with greater frailty (especially CFS≥6) associated with worse outcomes., including among younger patients.