Assessing ICU mortality among non-COVID-19 patients during the COVID-19 pandemic

The COVID-19 pandemic challenged healthcare infrastructure and delivery, particularly during peak periods. How these disruptions affected care and outcomes for non-COVID patients in intensive care units (ICUs) remains unclear.

To evaluate whether COVID-19 burden at the institutional and ICU level impacted ICU mortality among mechanically ventilated (MV) non-COVID patients across a health system.

Clinical data for ICU patients admitted within the University of Pittsburgh Medical Center system from March 2020 through December 2022 were included. High and low periods of COVID-19 were defined based on the average COVID-19 positivity rate across UPMC hospitals with high periods defined as months when the average positivity rate ≥10 %. A mixed-effects logistic regression evaluated the association between COVID-19 periods and ICU mortality with random intercepts for hospital and patient. Secondary models evaluated variation by ICU subtype and institution type. Models adjusted for demographic, clinical, and ICU characteristics.

Among 19,727 MV non-COVID ICU admissions, 10,798 occurred during high COVID-19 periods and 8929 during low periods. Baseline characteristics were similar with the largest age group being 60-69 years (28.1 % low vs 28.6 % high). Patients were predominantly White males admitted to quaternary hospitals. Admission during high COVID-19 periods was associated with higher ICU mortality (OR=1.19, 95 % CI: 1.08,1.31) particularly in MICUs (OR=1.18, 95 % CI: 1.14,1.22) and quaternary hospitals (OR=1.19, 95 % CI: 1.09,1.29).

High COVID-19 periods were associated with increased odds of ICU mortality among MV non-COVID-19 patients. These findings underscore the need for system-wide surge planning and incorporation of case-mix and workload measures in future evaluations.