1. In this retrospective cohort study, increased surge index during the Delta wave was associated with worse survival across various hospitals in the United States.
2. The relationship between COVID-19 caseload stress and mortality was consistent across hospitals with varying size, location, and infrastructure.
Evidence Rating Level: 2 (Good)
Study Rundown: While over a year has passed since the World Health Organization declared COVID-19 to no longer constitute a public health emergency of international concern, the pandemic has led to lasting effects in U.S. hospitals, including burnout and worsening of pre-existing staffing shortages. Variations in resources and infrastructure have been shown to produce inequities in care, particularly under increased caseload strain. The Delta variant-predominant phase of the COVID-19 pandemic, spanning from June to December 2021, provided an important opportunity to investigate whether certain hospital types were more resilient to caseload stress. This period was optimal for analysis for several reasons: significant improvements in COVID-19 management and survivability by this point thus minimizing variations in care; relatively uniform presentations of patients acutely ill with the Delta variant; and the influx of cases on the background of significant staffing shortages. Hence, this retrospective cohort study aimed to determine whether the care infrastructure provided by hospitals in the United States would impact patient outcomes during the Delta wave surge. Overall, higher surge indices during the study period were associated with increased mortality rates across various U.S. hospitals. A similar relationship between COVID-19 caseload stress and mortality was seen across all hospital types despite their varying care infrastructure. Further, the surge-mortality relationship appeared to be incremental, with no clear surge index decile above which mortality increased drastically. The study was limited by residual confounding variables including patients’ vaccination status and the availability of specific hospital provisions like continuous renal replacement therapy. Nonetheless, this study demonstrated that caseload strain during the Delta wave had detrimental effects on survival independent of hospital care infrastructure.
