Data Brief: Avoidable Emergency Department Visits Vary Widely Across California

The rate of Avoidable Emergency Department Visits per 1,000 member years varies widely by payer type. Rates for Californians with commercial coverage are consistently much lower (ranging from 13.5-19.4), measured by geography, than rates for those with Medicare coverage (ranging from 29.7-52.6); Medi-Cal rates are typically the highest (ranging from 46.7-64.7).

Introduction#

An emergency department (ED) visit is considered potentially avoidable when the condition that was treated could have been safely and effectively handled in a primary care setting such as a physician’s office, an urgent care center, or another outpatient setting. Examples of such conditions include sore throat, back pain, urinary tract infection, ear infection, and headache. The rate of potentially avoidable ED visits is an indicator with relevance for both quality and cost. A high rate of avoidable ED visits may indicate a lack of access to quality care in other settings. Multiple factors influence the rate of avoidable ED visits, including the availability of primary care and ED services, access to coverage and care, population health status, and the social factors within a region that affect people’s health. Treatment in an ED can lead to excessive testing or unnecessary procedures and compromise continuity of care. The ED setting is also higher intensity and higher cost compared to primary or urgent care settings. (Uscher-Pines L, Pines J, Kellermann A, Gillen E, Mehrotra A. Emergency department visits for nonurgent conditions: systematic literature review. Am J Manag Care. 2013 Jan;19(1):47-59. PMID: 23379744; PMCID: PMC4156292. https://pmc.ncbi.nlm.nih.gov/articles/PMC4156292/)

This report examines potentially avoidable ED visits across payer types and geographic areas of California using 2023 data from the Healthcare Payments Data (HPD) Program. Burden on EDs is a growing concern: the statewide median number of ED visits per treatment station in California increased 18% between 2021 and 2023, with higher ED burden in Health Professional Shortage Areas for Primary Care and Mental Health.

To adjust for population size and facilitate comparisons across regions, the number of avoidable ED visits per 1,000 member years is used. Geographic comparisons are based on counties and on California’s six Public Health Regions, as established by the California Department of Public Health Office: Rural North, Greater Sierra Sacramento, Bay Area, Central California, Southern California, and Los Angeles.

The underlying data is available for download and includes additional geographic units of analysis and measures.

For additional information about the HPD Program, including details on data sources, populations included, and data elements available, see HPD Public Reporting FAQ, HPD Resources and Technical Notes.

Key Findings#

• Overall, the Central California Public Health Region has the highest avoidable ED visit rate (43.7) while the Bay Area has the lowest (32.0).
• The commercial and Medicare data show a similar geographic pattern, with the lowest rates in the Los Angeles and the Southern California regions and the highest rates in the Rural North and Central California regions.
• For Medi-Cal members, region-specific rates of avoidable ED visits cluster around 60 visits per 1,000 member years, with the Rural North region as a low outlier (46.7).
• The region-level data on the Rural North region shows a different pattern from other regions. The Rural North is a high outlier for Medicare, as it has a higher rate of avoidable ED visits for Medicare beneficiaries compared to other regions, and a low outlier for Medi-Cal, as it has a lower rate for Medi-Cal members compared to other regions. Unlike other regions, the avoidable visit rate in the Rural North is higher for Medicare than it is for Medi-Cal. That could indicate that Medicare beneficiaries in the Rural North rely more heavily on the emergency room to obtain care compared to other regions, while Medi-Cal members rely less heavily on the ED.
• County-level data show significant variation in the rate of potentially avoidable ED visits within each region, with the highest county rate, typically 2-4 times the lowest county rate. For example, in the Bay Area region, the avoidable ED visit rate is about four times higher in San Benito (65.6) and Monterey (63.4), the counties with the highest rates, than in San Francisco (16.4), the county with the lowest rate. For Medi-Cal members, the rate is about five to six times higher: 125.3 in San Benito and 97.7 in Monterey compared to 21.7 in San Francisco.

Visualization#

Note: Avoidable ED visits are scaled to a rate of instances per 1,000 member years, meaning that the count of member months is divided by 1,000 and 12 (months).

Download Data#

The downloadable data includes a broader range of geographic units of analysis than have previously been made available in HPD public reports, in addition to other measures.

• Geography: County, Covered California Region, Public Health Region, California Assembly District, California Senate District, California Congressional District
• Demographics: Age Band, Sex
• Payer Type: Commercial, Medi-Cal, Medicare
• Measures: Prevalence of 23 chronic conditions, total ED visits, avoidable ED visits

How HCAI Created This Product#

• This report follows the California Health and Human Services Agency’s Data De-Identification Guidelines. Data from any group with less than 30 individuals are removed from the analyses and suppressed in the visualizations before calculating the measures or aggregating across groups. Suppression will result in some error in the reported rates, especially in counties with small populations or measures where prevalence and rates are generally lower. Use caution when interpreting results for individual counties with less than 30,000 residents. In addition, all reported group totals are rounded up to the nearest tens place value.
• This product uses a different suppression method than the Healthcare Payments Data (HPD) Measures: Health Conditions, Utilization, and Demographics Report. These differences in suppression methods will cause the overall numbers to differ between the two products.
• For information about measure definitions please see the HPD Healthcare Measures Technical Note (2018-2021) – October 2024.
• A Health Professional Shortage Area (HPSA) is a geographic area, population group, or healthcare facility that has been designated by the Health Resources and Services Administration (HRSA) as having a shortage of health professionals. There are three categories of HPSAs: Primary Care, Dental Health, and Mental Health.

Additional Information#

Topic: Cost Transparency / Healthcare Utilization
Source Link: Cost Transparency – Healthcare Payments Database
Citation: HCAI – Healthcare Payments Database – Avoidable Emergency Department Visits Vary Widely Across California, June 2025
Temporal Coverage: 2023
Spatial/Geographic Coverage: Statewide, County, Public Health Regions, Covered California Regions, Assembly Districts, Congressional Districts, Counties, and State Senate Districts
Frequency: Annually