The association of the COVID-19 pandemic and short-term outcomes of non-COVID-19 critically ill patients: an observational cohort study in Brazilian ICUs

Abstract

Purpose: To assess whether intensive care unit (ICU) outcomes for patients not affected by coronavirus disease 2019 (COVID-19) worsened during the COVID-19 pandemic.

Methods: Retrospective cohort study including prospectively collected information of patients admitted to 165 ICUs in a hospital network in Brazil between 2011 and 2020. Association between admission in 2020 and worse hospital outcomes was performed using different techniques, including assessment of changes in illness severity of admitted patients, a variable life-adjusted display of mortality during 2020, a multivariate mixed regression model with admission year as both fixed effect and random slope adjusted for SAPS 3 score, an analysis of trends in performance using standardized mortality ratio (SMR) and standardized resource use (SRU), and perturbation analysis.

Results: A total of 644,644 admissions were considered. After excluding readmissions and patients with COVID-19, 514,219 patients were available for analysis. Non-COVID-19 patients admitted in 2020 had slightly lower age and SAPS 3 score but a higher mortality (6.4%) when compared with previous years (2019: 5.6%; 2018: 6.1%). Variable-adjusted life display (VLAD) in 2020 increased but started to decrease as the number of COVID-19 cases increased; this trend reversed as number of COVID cases reduced but recurred on the second wave. After logistic regression, being admitted in 2020 was associated with higher mortality when compared to previous years from 2016 and 2019. Individual ICUs standardized mortality ratio also increased during 2020 (higher SMR) while resource use remained constant, suggesting worsening performance. A perturbation analysis further confirmed changes in ICU outcomes for non-COVID-19 patients.

Conclusion: Hospital outcomes of non-COVID-19 critically ill patients worsened during the pandemic in 2020, possibly resulting in an increased number of deaths in critically ill non-COVID patients.

Keywords: COVID-19; ICU performance; Standardized mortality ratio; Variable life-adjusted display.

Fig. 1

Trends in SAPS 3 score (a), age (a), hospital mortality (b), number of admissions (c), with COVID-19 confirmed and suspected admissions shown in red, and admission type (d) during the cohort. Continuous values are displayed as mean and standard deviation

Fig. 2

(a) Weekly cumulative Variable-adjusted life display (VLAD) during all weeks in 2020. Increases in VLAD suggest a lower-than-expected mortality, while downwards shifts suggest the inverse trend. (b) Number of COVID-19 cases admitted to the participating ICUs during the epidemiological weeks of 2020

Fig. 3

Odds ratio and their corresponding 95% confidence intervals for mortality in 2020 versus other years (x-axis) for fixed SAPS-3 scores (panels) obtained through marginal means. The dashed line marks OR = 1.00

Fig. 4

Trends in SMR (a) and SRU (b) for 61 ICUs with data available from 2016 to 2020. Error bars represent 95% confidence intervals obtained from 1000 replications bootstrap. The slope of changes in SMR, but not for SRU, in 2020 is different for 2016–2019 (p value for Chow test < 0.001 and 0.113, respectively). Results of the perturbation analysis for SMR (c) and SRU (d) for values before 2020 (blue) and 2019–2019 (purple). Perturbation scores represents how relatively far SMR and SRU values were from to the baseline. A comparison between each bimester in 2020 and baseline, as well as an averaged comparison between 2020 and 16-2019 is shown. p-values for Mann–Whitney U test after Bonferroni correction are shown in boxes