Estimates of Emergency Department Visits in the United States, 2016-2021

Based on International Classification of Diseases, 10th Revision, Clinical Modification (ICD–10–CM).  See Table 11 of the NHAMCS: 2020 Emergency Department Summary Tables for code ranges of diagnosis categories, available from: https://www.cdc.gov/nchs/data/nhamcs/web_tables/2020-nhamcs-ed-web-tables-508.pdf.

SOURCE: National Center for Health Statistics, National Hospital Ambulatory Medical Care Survey, 2016-2021

Based on the patient’s own words and coded according to: Schneider D, Appleton L, McLemore T. A reason for visit classification for ambulatory care. National Center for Health Statistics. See Appendix II of the 2020 NHAMCS public-use documentation for code ranges of reason categories, available from: https://ftp.cdc.gov/pub/Health_Statistics/NCHS/Dataset_Documentation/NHAMCS/doc20-ed-508.pdf.

SOURCE: National Center for Health Statistics, National Hospital Ambulatory Medical Care Survey, 2016-2021

Calculated by dividing the number of ED visits by estimates of the U.S. civilian noninstitutionalized population (obtained from the U.S. Census Bureau’s Population Division) for selected characteristics including age, sex, and race and ethnicity. Visit rates for MSA are based on estimates of the U.S. civilian noninstitutionalized population from the National Health Interview Survey, compiled according to the Office of Management and Budget definitions of core-based statistical areas. More information about MSA definitions is available from: https://www.census.gov/programs-surveys/metro-micro.html. Visit rates for patient’s expected source of payment are based on patient’s primary expected source of payment and proportional insurance data from the National Health Interview Survey.

During data collection, all sources of payment were collected. For patients with more than one source of payment, the hierarchy below was used (with Medicare counted first and self-pay and no charge counted last) to collapse payments into one mutually exclusive variable (expected source of payment). Visits that had a missing or unknown expected payment source were excluded (between 10-14% [weighted] from 2016-2021).

• Medicare: Partial or full payment by Medicare plan includes payments made directly to the hospital as well as payments reimbursed to the patient. Charges covered under a Medicare-sponsored prepaid plan are included.
• Medicaid: Partial or full payment by Medicaid plan includes payments made directly to the hospital or reimbursed to the patient. Charges covered under a Medicaid-sponsored prepaid plan (HMO) or “managed Medicaid” are included.
• Private: Partial or full payment by a private insurer (such as BlueCross BlueShield), either directly to the hospital or reimbursed to the patient. Charges covered under a private insurance-sponsored prepaid plan are included.
• Uninsured: Includes self-pay and no charge or charity. Self-pay are charges paid by the patient or patient’s family that will not be reimbursed by a third party. Self-pay includes visits for which the patient is expected to be responsible for most of the bill, even if the patient never actually pays it. This does not include copayments or deductibles. No charge or charity are visits for which no fee is charged (such as charity, special research, or teaching).
• Other: Includes Worker’s Compensation and other sources of payment not covered by the above categories, such as TRICARE, state and local governments, private charitable organizations, and other liability insurance (such as automobile collision policy coverage).

Race and Hispanic ethnicity were collected separately and converted into a single combined variable that includes non-Hispanic White, non-Hispanic Black, Hispanic, and non-Hispanic other people. Non-Hispanic other people includes Asian, Native Hawaiian or Other Pacific Islander, and American Indian or Alaska Native people, and people with two or more races. Missing values for race and ethnicity were imputed as described in the 2019 NHAMCS public-use documentation, available from: https://ftp.cdc.gov/pub/Health_Statistics/NCHS/Dataset_Documentation/NHAMCS/doc19-ed-508.pdf.