The study on COVID-19 caseload surges was led by Sameer S. Kadri, MD, MS, of the NIH Clinical Center (above), NIH's clinical research hospital.

The study on COVID-19 caseload surges was led by Sameer S. Kadri, MD, MS, of the NIH Clinical Center (above), NIH's clinical research hospital.

What you need to know

As of July 2021, more than 600,000 people had died of COVID-19 in the United States. At times over the last year and a half, some hospitals have been strained by the number of patients; many have also experienced shortages of personal protective equipment.

Working in collaboration with the Centers for Disease Control and Prevention, Harvard University, and Emory University, NIH researchers examined data from hospitals in the spring and summer of 2020 and found that COVID-19 patients were more likely to die in hospitals experiencing a sudden surge of patients.

What did the researchers do?

The researchers created a “surge index” to classify hospitals by how strained they were at a specific time. The surge index looked at not only the number of patients with COVID-19 at the hospital but also illness severity and the number of beds the hospital typically has. For example, given the same number of COVID-19 patients, a small hospital would have had a higher surge score than a large hospital, as would a hospital where more patients needed to be intubated.

The researchers analyzed data from 150,000 people with COVID-19 at 558 hospitals from March to August of 2020. More than half of these patients arrived during surges.

The researchers concluded that nearly 1 in 4 COVID-19 deaths among these 150,000 patients may have occurred as a result of hospitals being strained by COVID-19.

Why is this research important?

Supporting surging hospitals could save lives, the researchers wrote. For example, a hospital could track its own surge score and plan to increase staffing and supplies when the score increases. The researchers emphasized that vaccines and other preventive measures are the best way to avoid overloading hospitals with COVID-19 patients.

Where can I go to learn more?

NIH Study Associates COVID-19 Surges With Mortality Increases for Patients

NIH shares information about this study, which was conducted in collaboration with colleagues at the Centers for Disease Control and Prevention.

Hospitals Reported That the COVID-19 Pandemic Has Significantly Strained Health Care Delivery

A February report from the U.S. Department of Health and Human Services Office of Inspector General says that hospitals struggled to operate in “survival mode” for an extended period.

National Institute of Environmental Health Sciences (NIEHS) COVID-19 Resources

NIEHS has information in English, Spanish, Chinese, and Vietnamese on protecting workers — including hospital staff — from COVID-19 in the workplace.


Kadri, S. S., Sun, J., Lawandi, A., Strich, J. R., Busch, L. M., Keller, M., Babiker, A., Yek, C., Malik, S., Krack, J., Dekker, J. P., Spaulding, A. B., Ricotta, E., Powers, J. H. III, Rhee, C., Klompas, M., Athale, J., Boehmer, T. K., Gundlapalli, A. V., Bentley, W., … Warner, S. (2021). Association between caseload surge and COVID-19 survival in 558 U.S. hospitals, March to August 2020. Annals of Internal Medicine, M21-1213. Advance online publication.


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Page last updated: August 9, 2021