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.

Five-Year Mortality and Hospital Costs Associated with Surviving Intensive Care.

RATIONALE: Survivors of critical illness experience significant morbidity, but the impact of surviving the intensive care unit (ICU) has not been quantified comprehensively at a population level. OBJECTIVES: To identify factors associated with increased hospital resource use and to ascertain whether ICU admission was associated with increased mortality and resource use. METHODS: Matched cohort study and pre/post-analysis using national linked data registries with complete population coverage. The population consisted of patients admitted to all adult general ICUs during 2005 and surviving to hospital discharge, identified from the Scottish Intensive Care Society Audit Group registry, matched (1:1) with similar hospital control subjects. Five-year outcomes included mortality and hospital resource use. Confounder adjustment was based on multivariable regression and pre/post within-individual analyses. MEASUREMENTS AND MAIN RESULTS: Of 7,656 ICU patients, 5,259 survived to hospital discharge (5,215 [99.2%] matched to hospital control subjects). Factors present before ICU admission (comorbidities/pre-ICU hospitalizations) were stronger predictors of hospital resource use than acute illness factors. In the 5 years after the initial hospital discharge, compared with hospital control subjects, the ICU cohort had higher mortality (32.3% vs. 22.7%; hazard ratio, 1.33; 95% confidence interval, 1.22-1.46; P < 0.001), used more hospital resources (mean hospital admission rate, 4.8 vs. 3.3/person/5 yr), and had 51% higher mean 5-year hospital costs ($25,608 vs. $16,913/patient). Increased resource use persisted after confounder adjustment (P < 0.001) and using pre/post-analyses (P < 0.001). Excess resource use and mortality were greatest for younger patients without significant comorbidity. CONCLUSIONS: This complete, national study demonstrates that ICU survivorship is associated with higher 5-year mortality and hospital resource use than hospital control subjects, representing a substantial burden on individuals, caregivers, and society.

External validation of the Intensive Care National Audit & Research Centre (ICNARC) risk prediction model in critical care units in Scotland.

BACKGROUND: Risk prediction models are used in critical care for risk stratification, summarising and communicating risk, supporting clinical decision-making and benchmarking performance. However, they require validation before they can be used with confidence, ideally using independently collected data from a different source to that used to develop the model. The aim of this study was to validate the Intensive Care National Audit & Research Centre (ICNARC) model using independently collected data from critical care units in Scotland. METHODS: Data were extracted from the Scottish Intensive Care Society Audit Group (SICSAG) database for the years 2007 to 2009. Recoding and mapping of variables was performed, as required, to apply the ICNARC model (2009 recalibration) to the SICSAG data using standard computer algorithms. The performance of the ICNARC model was assessed for discrimination, calibration and overall fit and compared with that of the Acute Physiology And Chronic Health Evaluation (APACHE) II model. RESULTS: There were 29,626 admissions to 24 adult, general critical care units in Scotland between 1 January 2007 and 31 December 2009. After exclusions, 23,269 admissions were included in the analysis. The ICNARC model outperformed APACHE II on measures of discrimination (c index 0.848 versus 0.806), calibration (Hosmer-Lemeshow chi-squared statistic 18.8 versus 214) and overall fit (Brier's score 0.140 versus 0.157; Shapiro's R 0.652 versus 0.621). Model performance was consistent across the three years studied. CONCLUSIONS: The ICNARC model performed well when validated in an external population to that in which it was developed, using independently collected data.

Influence of socioeconomic deprivation on interventions and outcomes for patients admitted with COVID-19 to critical care units in Scotland: A national cohort study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) can lead to significant respiratory failure with between 14% and 18% of hospitalised patients requiring critical care admission. This study describes the impact of socioeconomic deprivation on 30-day survival following critical care admission for COVID-19, and the impact of the COVID-19 pandemic on critical care capacity in Scotland. METHODS: This cohort study used linked national hospital records including ICU, virology testing and national death records to identify and describe patients with COVID-19 admitted to critical care units in Scotland. Multivariable logistic regression was used to assess the impact of deprivation on 30-day mortality. Critical care capacity was described by reporting the percentage of baseline ICU bed utilisation required. FINDINGS: There were 735 patients with COVID-19 admitted to critical care units across Scotland from 1/3/2020 to 20/6/2020. There was a higher proportion of patients from more deprived areas, with 183 admissions (24.9%) from the most deprived quintile and 100 (13.6%) from the least deprived quintile. Overall, 30-day mortality was 34.8%. After adjusting for age, sex and ethnicity, mortality was significantly higher in patients from the most deprived quintile (OR 1.97, 95%CI 1.13, 3.41, p=0.016). ICUs serving populations with higher levels of deprivation spent a greater amount of time over their baseline ICU bed capacity. INTERPRETATION: Patients with COVID-19 living in areas with greatest socioeconomic deprivation had a higher frequency of critical care admission and a higher adjusted 30-day mortality. ICUs in health boards with higher levels of socioeconomic deprivation had both higher peak occupancy and longer duration of occupancy over normal maximum capacity. FUNDING: None.

The association between ICU admission and emergency hospital readmission following emergency general surgery.

BACKGROUND: The relationship between postoperative intensive care (ICU) admission following emergency general surgery (EGS) and emergency hospital readmission has not been widely investigated. METHODS: Retrospective analysis of registry data for patients undergoing EGS in Scotland, 2005-2007. Exposure of interest was ICU admission status (direct from theatre; indirect after initial care on ward; no ICU admission). The primary outcome was emergency hospital readmission within 30 days of discharge. RESULTS: Thirty-seven thousand one hundred seventy-three patients were included in the analysis. Overall emergency readmission rate was 8% (n = 2983): 2756 (7.8%) in patients without postoperative ICU admission; 155 (12.1%) with direct ICU admission and 65 (14.7%) with indirect ICU admission. Indirect ICU admission was associated with increased hospital readmission rates (HR 1.24 [1.03, 1.49]; p = 0.024) compared with direct ICU admission. ICU admission was associated with increased three-year readmission rates (p = 0.006) and costs (p < 0.001) compared with initial ward care. CONCLUSION: Indirect ICU admission is associated with increased emergency hospital readmission and healthcare costs for patients undergoing EGS.