Prevalence, characteristics, and longer-term outcomes of patients with persistent critical illness attributable to COVID-19 in Scotland: a national cohort study

BACKGROUND: Patients with COVID-19 can require critical care for prolonged periods. Patients with persistent critical Illness can have complex recovery trajectories, but this has not been studied for patients with COVID-19. We examined the prevalence, risk factors, and long-term outcomes of critically ill patients with COVID-19 and persistent critical illness. METHODS: This was a national cohort study of all adults admitted to Scottish critical care units with COVID-19 from March 1, 2020 to September 4, 20. Persistent critical illness was defined as a critical care length of stay (LOS) of ≥10 days. Outcomes included 1-yr mortality and hospital readmission after critical care discharge. Fine and Gray competing risk analysis was used to identify factors associated with persistent critical Illness with death as a competing risk. RESULTS: A total of 2236 patients with COVID-19 were admitted to critical care; 1045 patients were identified as developing persistent critical Illness, comprising 46.7% of the cohort but using 80.6% of bed-days. Patients with persistent critical illness used more organ support, had longer post-critical care LOS, and longer total hospital LOS. Persistent critical illness was not significantly associated with long-term mortality or hospital readmission. Risk factors associated with increased hazard of persistent critical illness included age, illness severity, organ support on admission, and fewer comorbidities. CONCLUSIONS: Almost half of all patients with COVID-19 admitted to critical care developed persistent critical illness, with high resource use in critical care and beyond. However, persistent critical illness was not associated with significantly worse long-term outcomes compared with patients who were critically ill for shorter periods.