Trends in Intensive Care for Patients with COVID-19 in England, Wales, and Northern Ireland

Abstract

Rationale: By describing trends in intensive care for patients with coronavirus disease (COVID-19) we aim to support clinical learning, service planning, and hypothesis generation.Objectives: To describe variation in ICU admission rates over time and by geography during the first wave of the epidemic in England, Wales, and Northern Ireland; to describe trends in patient characteristics on admission to ICU, first-24-hours physiology in ICU, processes of care in ICU and patient outcomes; and to explore deviations in trends during the peak period.Methods: A cohort of 10,741 patients with COVID-19 in the Case Mix Program national clinical audit from February 1 to July 31, 2020, was used. Analyses were stratified by time period (prepeak, peak, and postpeak periods) and geographical region. Logistic regression was used to estimate adjusted differences in 28-day in-hospital mortality between periods.Measurements and Main Results: Admissions to ICUs peaked almost simultaneously across regions but varied 4.6-fold in magnitude. Compared with patients admitted in the prepeak period, patients admitted in the postpeak period were slightly younger but with higher degrees of dependency and comorbidity on admission to ICUs and more deranged first-24-hours physiology. Despite this, receipt of invasive ventilation and renal replacement therapy decreased, and adjusted 28-day in-hospital mortality was reduced by 11.8% (95% confidence interval, 8.7%-15.0%). Many variables exhibited u-shaped or n-shaped curves during the peak.Conclusions: The population of patients with COVID-19 admitted to ICUs, and the processes of care in ICUs, changed over the first wave of the epidemic. After adjustment for important risk factors, there was a substantial improvement in patient outcomes.

Keywords: COVID-19; United Kingdom; intensive care; mortality; trends.

Figure 1.

Coronavirus disease (COVID-19) critical care admission rates. (A) New ICU admissions, transfers and readmissions, and patients remaining in the ICU all contribute to the total number of patients in the ICU. (B) Regions are the National Health Service–commissioning regions, denominators are Office for National Statistics estimates of the mid-2019 regional population aged 15 years and over (13), and moving averages are linearly weighted averages ± 7 days.

Figure 2.

Trends in characteristics of patients with coronavirus disease (COVID-19) on admission to ICUs. The lines are the moving averages and linearly weighted averages ± 7 days. Patients first admitted during February or July are not presented because of the small numbers. BMI = body mass index; CI = confidence interval.

Figure 3.

Trends in patients with coronavirus disease (COVID-19) first-24-hours physiology in ICUs. The lines are the moving averages and linearly weighted averages ± 7 days. Patients first admitted during February or July are not presented because of the small numbers. APACHE II = Acute Physiology and Chronic Health Evaluation; CI = confidence interval; KDIGO = Kidney Disease: Improving Global Outcomes.

Figure 4.

Trends in the coronavirus disease (COVID-19) processes of care in ICUs and outcomes. The lines are moving averages and linearly weighted averages ± 7 days. Patients first admitted during February or July were not shown because of the small numbers. The durations are capped and stratified by survivorship at 28 days. CI = confidence interval.

Figure 5.

Adjusted 28-day in-hospital mortality, by time period and geography. The estimates represent the average marginal predicted risk of 28-day mortality for a patient with the mean values for all covariates, fitted after a multiple logistic regression. The results were adjusted for age, sex, ethnicity, quintile of deprivation, body mass index, any dependency before hospital admission, immunocompromised, sedated for entire of first 24 hours, highest temperature, lowest systolic blood pressure, highest heart rate, highest respiratory rate, Pa_O2/Fi_O2 ratio, highest blood lactate concentration, highest serum creatinine, highest serum urea, lowest Hb concentration, and lowest platelet count. CI = confidence interval.