The first 20 months of the COVID-19 pandemic: Mortality, intubation and ICU rates among 104,590 patients hospitalized at 21 United States health systems

Abstract

Main objective There is limited information on how patient outcomes have changed during the COVID-19 pandemic. This study characterizes changes in mortality, intubation, and ICU admission rates during the first 20 months of the pandemic. Study design and methods University of Wisconsin researchers collected and harmonized electronic health record data from 1.1 million COVID-19 patients across 21 United States health systems from February 2020 through September 2021. The analysis comprised data from 104,590 adult hospitalized COVID-19 patients. Inclusion criteria for the analysis were: (1) age 18 years or older; (2) COVID-19 ICD-10 diagnosis during hospitalization and/or a positive COVID-19 PCR test in a 14-day window (+/- 7 days of hospital admission); and (3) health system contact prior to COVID-19 hospitalization. Outcomes assessed were: (1) mortality (primary), (2) endotracheal intubation, and (3) ICU admission. Results and significance The 104,590 hospitalized participants had a mean age of 61.7 years and were 50.4% female, 24% Black, and 56.8% White. Overall risk-standardized mortality (adjusted for age, sex, race, ethnicity, body mass index, insurance status and medical comorbidities) declined from 16% of hospitalized COVID-19 patients (95% CI: 16% to 17%) early in the pandemic (February-April 2020) to 9% (CI: 9% to 10%) later (July-September 2021). Among subpopulations, males (vs. females), those on Medicare (vs. those on commercial insurance), the severely obese (vs. normal weight), and those aged 60 and older (vs. younger individuals) had especially high mortality rates both early and late in the pandemic. ICU admission and intubation rates also declined across these 20 months. Conclusions Mortality, intubation, and ICU admission rates improved markedly over the first 20 months of the pandemic among adult hospitalized COVID-19 patients although gains varied by subpopulation. These data provide important information on the course of COVID-19 and identify hospitalized patient groups at heightened risk for negative outcomes. Trial registration ClinicalTrials.gov Identifier: NCT04506528 (https://clinicaltrials.gov/ct2/show/NCT04506528).

Characteristics of COVID-19 patients with multiorgan injury across the pandemic in a large academic health system in the Bronx, New York

“…A significant number of patients who visited the ED were hospitalized. ICU admission was relatively constant across the pandemic, likely reflecting the maximum ICU capacity assigned for COVID-19 patients [ 42 , 43 ]. The majority of death occurred during the first wave.…”

Factors associated with 60‐day readmission among inpatients with COVID‐19 at 21 United States health systems

“…The COVID EHR Cohort at the University of Wisconsin (CEC‐UW) is a retrospective cohort study supported by the National Cancer Institute (http://ClinicalTrials.gov: NCT04506528). The CEC‐UW cohort includes data from 21 health systems from across the United States (see Figure ) 11 . Data were abstracted from the EHR for all COVID‐19 cases between February 1, 2020 and January 31, 2022, when the study period ended.…”

“…Figure 1 presents patient selection into the study population and reasons for exclusions. Consistent with prior research, 11,13 patients were excluded from the study population of inpatients for one or more of the following reasons: (1) duration of hospitalization lasted <24 h (not due to death or transfer to intensive care; this criterion was imposed to remove observational stays from the analyzed sample); (2) patients had neither a positive COVID‐19 PCR test in a 14‐day window from 7 days before 7 days following admission nor an ICD‐10 COVID‐19 diagnosis during their hospitalization (to exclude patients without COVID‐19), and (3) patients had no prior inpatient or outpatient contact with the health system in the past 5 years (to ensure comorbidity data were available and increase the likelihood of capturing readmissions). Patients were also excluded from the analysis of readmissions if they (1) were <18 years old, (2); had less than 60‐days follow‐up between discharge and readmission up to January 31, 2022; or (3) died during the index admission.…”

“…Important questions remain regarding COVID‐19 readmission rates and predictors since mid‐2020. Studies have shown that mortality, intensive care unit admission, and intubation rates declined over the course of the pandemic 9–11 . Readmission rates and factors associated with readmission and severe outcomes at readmission (e.g., need for intensive care and mortality) also may have changed after COVID‐19 vaccine authorization in the United States on December 11, 2020 12 .…”

COVID-19 pandemic in the intensive care unit: Psychological implications and interventions, a systematic review

“…Intensive care unit (ICU) utilisation during the coronavirus disease 2019 (COVID-19) pandemic accounted for around 25% of patients hospitalised during the February 2020 to September 2021 period in 21 United States Healthcare systems[ 1 ]. The COVID-19 pandemic has produced changes in ICUs both in patient care and in hospital care organization.…”