Effect of a Nationwide Mass Casualty Event on Intensive Care Units: Clinical Outcomes and Associated Cost-of-Care in the First Six Months of Response to SARS-CoV-2

Abstract

RATIONALE: Mass casualty events (MCE) are situations that overwhelm local capacity and lead to morbidity and mortality. The SARS-CoV-2 pandemic (COVID-19) can be considered a nationwide sustained MCE that affected multiple aspects of healthcare. We hypothesized that the surge of patients and lack of preparation for MCEs resulted in increased patient length of stay (LOS), complications, mortality, and costs associated with care for critically ill patients. METHODS: A multicenter, retrospective cohort study compared patients admitted to an intensive care unit (ICU) in 2019 to 2020. The timeframe was March to August. In 2020, this was the first six months of the nationwide response to COVID-19. 2019 was the historical control. Data were collected from the Vizient Clinical Data Base/Resource Manager™ (CDB/RM) (Irving, TX), a national database of patient outcomes and cost-data from over 700 tertiary/quaternary and community hospitals. Data is reported with an associated severity of illness score. The total number of ICU admissions, complication percentage, ICU LOS, observed and expected LOS, LOS index (ratio of observed-to-expected LOS), observed and expected mortality rate, mortality index (ratio of observed-to-expected mortality), total cost of admission, observed and expected direct cost of admission, and direct cost index (ratio of observed-to-expected direct cost) were collected. Inclusion criteria were all medical centers with complete datasets for the timeframe. All major geographic regions of the United States were included. IBM SPSS Statistics for Windows, version 27.0 (Armonk, NY) was used to summarize data with mean and standard deviation. Independent sample two-sided t-tests were used to compare subgroup means. All cost data were adjusted for inflation using the consumer price index. RESULTS: Twenty health systems and 42,397 patients were included in the study. There was a significant increase from 2019 to 2020 in patient outcomes and cost-of-care (table 1). In 2020, ICU LOS was longer compared to 2019;this was highest at tertiary centers [1.5 days longer] and metropolitan hospitals [1.2 days longer]. There was 1.4% increase in complication rates;this was highest in community hospitals [1.8%] and hospitals in urban regions [1.8%]. On average, the total cost of admission per ICU patient was $5,522 more in 2020. This was highest for tertiary academic centers [$6,870] followed by metropolitan hospitals [$6,469], community hospitals [$4,945] and rural hospitals [$4,102]. CONCLUSION: The MCE caused by the SARS-CoV-2 virus resulted in increased adverse outcomes and cost-of-care for patients admitted to an ICU during the first six months of disaster response.