ICU Mortality Across Prepandemic and Pandemic Cohorts in a Resource-Limited Setting: A Critical Care Resiliency Analysis From South Africa

Abstract

Background: Hospital adaptation and resiliency, required during public health emergencies to optimize outcomes, are understudied especially in resource-limited settings.

Research question: What are the prepandemic and pandemic critical illness outcomes in a resource-limited setting and in the context of capacity strain?

Study design and methods: We performed a retrospective cohort study among patients admitted to ICUs at two public hospitals in the KwaZulu-Natal Department of Health in South Africa preceding and during the COVID-19 pandemic (2017-2022). We used multivariate logistic regression to analyze the association between three patient cohorts (prepandemic non-COVID-19, pandemic non-COVID-19, and pandemic COVID-19) and ICU capacity strain and the primary outcome of ICU mortality.

Results: Three thousand two hundred twenty-one patients were admitted to the ICU during the prepandemic period and 2,539 patients were admitted to the ICU during the pandemic period (n = 375 [14.8%] with COVID-19 and n = 2,164 [85.2%] without COVID-19). The prepandemic and pandemic non-COVID-19 cohorts were similar. Compared with the non-COVID-19 cohorts, the pandemic COVID-19 cohort showed older age, higher rates of chronic cardiovascular disease and diabetes, less extrapulmonary organ dysfunction, and longer ICU length of stay. Compared with the prepandemic non-COVID-19 cohort, the pandemic non-COVID-19 cohort showed similar odds of ICU mortality (OR, 1.06; 95% CI, 0.90-1.25; P = .50) whereas the pandemic COVID-19 cohort showed significantly increased odds of ICU mortality (OR, 3.91; 95% CI, 3.03-5.05 P < .0005). ICU occupancy was not associated with ICU mortality in either the COVID-19 cohort (OR, 1.05 per 10% change in ICU occupancy; 95% CI, 0.96-1.14; P = .27) or the pooled non-COVID-19 cohort (OR, 1.01 per 10% change in ICU occupancy; 95% CI, 0.98-1.03; P = .52).

Interpretation: Patients admitted to the ICU before and during the pandemic without COVID-19 were broadly similar in clinical characteristics and outcomes, suggesting critical care resiliency, whereas patients admitted to the ICU with COVID-19 showed important clinical differences and significantly higher mortality.

Keywords: COVID-19; capacity strain; hospital adaptation; hospital resiliency; preparedness.

Figure 1 –

Graph showing ICU occupancy and SARS-CoV-2 cases and variant surges. ICU occupancy (green line) at the time of study patient ICU admissions and standardized to prepandemic ICU capacity and national SARS-CoV-2 incident cases (purple line) are plotted spanning the prepandemic period and across five pandemic surges with dominant SARS-CoV-2 viral variants depicted by shaded areas. Compared with the prepandemic period, the study hospitals and patients admitted during the pandemic period experienced higher ICU occupancy (median, 100.0% [interquartile range (IQR), 80.0%–122.2%] of prepandemic ICU capacity). A median of 100% occupancy indicates that at the time of 50% of ICU admissions during the pandemic, ICU surge beds beyond prepandemic ICU capacity were in use. ICU occupancy was highest during the Beta variant (median, 115.9% [IQR, 90.9%–144.4%] of prepandemic ICU capacity) and Delta variant (median, 131.8% [IQR, 106.7%–150.6%] of prepandemic ICU capacity) surges.

Figure 2 –

Graph showing predicted ICU mortality among patients without and with COVID-19 by ICU occupancy. ICU occupancy was not associated with ICU mortality in either the COVID-19 cohort (OR, 1.05 per 10% change in ICU occupancy; 95% CI, 0.96–1.14; P = .27) or the non-COVID-19 cohort pooled across prepandemic and pandemic periods (OR, 1.01 per 10% change in ICU occupancy; 95% CI, 0.98–1.03; P = .52), adjusting for patient-level covariates. The figure reports predicted ICU mortality by ICU occupancy decile (with decile 1 being lowest occupancy and decile 10 being highest occupancy) with differences between the non-COVID-19 and COVID-19 cohorts, but no apparent differences within each cohort.