Potential Indirect Effects of the COVID-19 Pandemic on Use of Emergency Departments for Acute Life-Threatening Conditions

United States, January-May 2020

Samantha J. Lange, MPH; Matthew D. Ritchey, DPT; Alyson B. Goodman, MD; Taylor Dias, MPH; Evelyn Twentyman, MD; Jennifer Fuld, PhD; Laura A. Schieve, PhD; Giuseppina Imperatore, MD, PhD; Stephen R. Benoit, MD; Aaron Kite-Powell, MS; Zachary Stein, MPH; Georgina Peacock, MD; Nicole F. Dowling, PhD; Peter A. Briss, MD; Karen Hacker, MD; Adi V. Gundlapalli, MD, PhD; Quanhe Yang, PhD


Morbidity and Mortality Weekly Report. 2020;59(25):795-800. 

In This Article

Abstract and Introduction


On March 13, 2020, the United States declared a national emergency in response to the coronavirus disease 2019 (COVID-19) pandemic. Subsequently, states enacted stay-at-home orders to slow the spread of SARS-CoV-2, the virus that causes COVID-19, and reduce the burden on the U.S. health care system. CDC* and the Centers for Medicare & Medicaid Services (CMS) recommended that health care systems prioritize urgent visits and delay elective care to mitigate the spread of COVID-19 in health care settings. By May 2020, national syndromic surveillance data found that emergency department (ED) visits had declined 42% during the early months of the pandemic.[1] This report describes trends in ED visits for three acute life-threatening health conditions (myocardial infarction [MI, also known as heart attack], stroke, and hyperglycemic crisis), immediately before and after declaration of the COVID-19 pandemic as a national emergency. These conditions represent acute events that always necessitate immediate emergency care, even during a public health emergency such as the COVID-19 pandemic. In the 10 weeks following the emergency declaration (March 15–May 23, 2020), ED visits declined 23% for MI, 20% for stroke, and 10% for hyperglycemic crisis, compared with the preceding 10-week period (January 5–March 14, 2020). EDs play a critical role in diagnosing and treating life-threatening conditions that might result in serious disability or death. Persons experiencing signs or symptoms of serious illness, such as severe chest pain, sudden or partial loss of motor function, altered mental state, signs of extreme hyperglycemia, or other life-threatening issues, should seek immediate emergency care, regardless of the pandemic. Clear, frequent, highly visible communication from public health and health care professionals is needed to reinforce the importance of timely care for medical emergencies and to assure the public that EDs are implementing infection prevention and control guidelines that help ensure the safety of their patients and health care personnel.

CDC used data from its National Syndromic Surveillance Program (NSSP) to assess trends in ED visits from week 1, 2019 through week 21, 2020 for three life-threatening health conditions: MI, stroke, and hyperglycemic crisis. NSSP is a collaboration among CDC, federal partners, local and state health departments, and academic and private sector partners to collect, analyze, and share electronic patient encounter data received from emergency departments, urgent and ambulatory care centers, inpatient health care settings, and laboratories for public health action.§ NSSP includes ED visits from a subset of hospitals in 47 states (all but Hawaii, South Dakota, and Wyoming) and the District of Columbia, capturing approximately 73% of ED visits nationwide. These analyses were limited to EDs with consistent ≥90% completeness for patient discharge diagnosis to ensure data quality (1,670 EDs). The three conditions were defined using the following International Classification of Diseases, Tenth Revision (ICD-10) codes: MI = I21–I22; stroke = I60–I61 (hemorrhagic stroke) or I63 (ischemic stroke); and hyperglycemic crisis = E10.1, E11.1, or E13.1 (diabetic ketoacidosis) or E11.0, E13.0, or E10.65 and E10.69 (hyperosmolar hyperglycemic syndrome). Weekly numbers of ED visits for each of the three conditions were compared for two 10-week periods: January 5–March 14, 2020 (weeks 2–11, prepandemic) and March 15–May 23, 2020 (weeks 12–21, early pandemic). The absolute differences and percentage change in number of visits from pre- to early pandemic periods were tabulated, overall and within age-sex strata. Analyses were conducted using SAS (version 9.4; SAS Institute).

Trends in number of ED visits for MI and stroke were relatively stable during the first half of 2019, increased slightly in the second half of 2019, and then stabilized during the first few weeks of 2020, remaining stable throughout the prepandemic period (Figure 1). The number of ED visits for MI and stroke declined sharply starting at week 10 (corresponding to the week beginning March 1, 2020) and reaching the lowest level during weeks 13–14 (weeks beginning March 22 for MI and March 29 for stroke), coinciding with the early weeks after the declaration of the COVID-19 national emergency. Since the nadir, ED visits for MI and stroke have gradually increased but remain below prepandemic levels. Compared with the prepandemic period, the number of ED visits during the early pandemic period was 23% lower for MI and 20% lower for stroke (Table). The number of ED visits for hyperglycemic crisis followed similar, albeit less pronounced, trends to those observed for MI and stroke; the number of ED visits for hyperglycemic crisis was 10% lower during the early pandemic than during the prepandemic period, with the lowest level occurring at week 14. The reduction in visits for all three conditions during the early pandemic was similar in males and females.

Figure 1.

Number of emergency department (ED) visits for myocardial infarction, stroke, and hyperglycemic crisis* — National Syndromic Surveillance Program, United States, week 1, 2019–week 21, 2020
Abbreviation: COVID-19 = coronavirus disease 2019.
*Includes diabetic ketoacidosis and hyperosmolar hyperglycemic syndrome.
Week 1, 2019 (week ending January 5, 2019) to week 21, 2020 (week ending May 23, 2020).

The relative decline in the number of ED visits between the prepandemic and early pandemic periods was similar across age groups for MI and stroke, whereas the decline in ED visits for hyperglycemic crisis tended to be larger among younger age groups, particularly for females (Table). The absolute decrease in ED visits for MI was largest among persons aged 65–74 years for both men (2,114-visit decrease) and women (1,459) (Figure 2). The absolute decrease in ED visits for stroke was largest among men aged 65–74 years (1,406-visit decrease) and women aged 75–84 years (1,642). The absolute decrease in ED visits for hyperglycemic crisis was largest in younger adults aged 18–44 years (419-visit decrease for men, 775 for women).

Figure 2.

Absolute decreases in number of emergency department (ED) visits for myocardial infarction, stroke, and hyperglycemic crisis between COVID-19 prepandemic* and early pandemic periods, by sex and age group§ — National Syndromic Surveillance Program, United States, 2020
Abbreviation: COVID-19 = coronavirus disease 2019.
*Prepandemic (weeks 2–11) corresponds to January 5–March 14, 2020.
Early pandemic (weeks 12–21) corresponds to March 15–May 23, 2020.
§There was a slight absolute increase in ED visits for stroke among males aged 0–17 years and for hyperglycemic crisis among females aged 75–84 years.

§ https://www.cdc.gov/nssp/index.html.
During weeks 2–21, 2020, an average of 3,504 EDs reported to NSSP. On average, 1,670 EDs (48%) had consistent (≥90%) completeness on patient discharge diagnosis data during this period.