EpiCenter is an interactive tool for viewing California data on injuries that resulted in death, hospitalization, or an emergency department (ED) visit.
Causes of injuries are classified according to intent and mechanism, or the vector that delivered the energy to the body to cause the injury.
The figure below shows the composition of California injury deaths, hospitalizations, or ED visits by cause for the most recent data year.
by Intent and Mechanism
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Dig deeper into California injury data by selecting an injury outcome – death, hospitalization, or ED visit – from the blue panel at the top of the page. For each injury outcome, you will be able to filter the data,
display custom tables, graph trends over time, and more. A detailed user guide and documentation can be viewed from the light grey panel on the left.
Injury data are the foundation for action. To learn what the California Department of Public Health is doing to help prevent injuries, visit the Injury and Violence Prevention Branch
(IVPB) home page.
EpiCenter is designed to be a flexible tool for viewing California data on injuries that result in death, hospitalization, or a visit to the emergency department (ED). Follow these three steps below to start exploring the data.
1. Select
Select the injury outcome from the blue panel at the top of the page. Outcomes include deaths, non-fatal hospitalizations, and non-fatal ED visits (Figure 1). Non-fatal hospitalizations tend to be for more severe injuries that require greater medical treatment compared to ED visits.
Figure 1: Select injury outcome
2. Filter
Filter the injury data using the drop-down menu on the left of the page (Figure 2-A). Filters are organized under the categories of person, place, time, injury, and treatment (for non-fatal injuries only). Click on a category to view/hide the filters it contains. To select or de-select multiple categories from a list, use the control key (command key on a Mac). Filters will be immediately applied. A description of the current filters and the number of injuries displayed appears near the top of the page, under the blue panel (Figure 2-B). To clear all filters, click on the “clear all filter” button at the bottom of the filter panel on the left of the page (Figure 2-C).
Figure 2: Filter injury data
3. Display
Display the data using the three outputs listed as tabs under the description of the filtered data.
Custom Table: Displays injury counts by selected variables. The data can be grouped by up to four variables using the drop-down menus above the table (Figure 3-A). The table will display injury counts for each grouping level. Check the “show rates” box to also display incidence rates per 100,000 person-years (Figure 3-B). To download the table as an Excel file, click on the box below the table (Figure 3-C).
Figure 3: Custom table display
Time Series: Displays injuries over time as a line graph. Group the data by variables from the drop-down menu above the graph (please note the graph is limited to displaying 10 or fewer groups) (Figure 4-A). Choose to display injury counts or incidence rates from the next drop-down menu (Figure 4-B). Change the time unit from years to months or weeks using the third drop-down menu (Figure 4-C). Hover over the graph to see values for each data point (Figure 4-D). To download the graph as an image (.png file), hover over the table and a camera icon will appear in the top right corner – click on it (Figure 4-E). To download the graph’s source data as a table (Excel file), click on the “Excel” box below the graph (Figure 4-F).
Figure 4: Time series display
Bar Chart: Displays injuries by groups as a bar chart. Group the data by variables from the drop-down menu above the chart (please note the chart is limited to displaying 120 or fewer groups) (Figure 5-A). Choose to display injury counts or incidence rates from the next drop-down menu (Figure 5-B). Change the bar order from the grouping variable (groups) order to the bar height (injury measure) order using the third drop-down menu (Figure 5-C). Hover over the chart to see values for each bar (Figure 5-D). To download the chart as an image (.png file), hover over the table and a camera icon will appear in the top right corner – click on it (Figure 5-E). To download the chart’s source data as a table (Excel file), click on the “Excel” box below the graph (Figure 5-F).
Figure 5: Bar chart display
Suggested Analyses
EpiCenter is designed to be flexible and support a wide a variety of injury data analyses. Here are three suggestions to get started.
1. Leading causes of injury
Those working to improve the health of a specific population may benefit from knowing the causes of injury that contribute to the most morbidity or mortality among that specific population. The Custom Table display can provide that information. First, select the injury outcome of interest and filter the data to the population of interest. The example below looks at injury hospitalizations among children under the age of 18 for the year 2020 (Figure 6). In the custom table display, choose to group the data by injury intent then by injury mechanism (Figure 6-A). Next, sort the table by injury counts in descending order (Figure 6-B). The table will now show the intent-by-mechanism causes of injuries that contributed to the most hospitalizations among the population of interest. Note that intent-by-mechanism causes of injuries are not always used to rank leading causes of injury. Sometimes mechanism groups are consolidated (e.g., all motor vehicle traffic [MVT] injury classifications are consolidated into a single MVT group) and sometimes intent groups are consolidated (e.g., all mechanisms of self-harm injuries are consolidated into a single self-harm group).
Figure 6: Suggested analysis to identify leading causes of injury
Each intent-by-mechanism cause group consists of ICD-10 or ICD-10-CM codes that correspond to specific injuries. To identify the specific codes/injuries within an intent-by-mechanism cause group, further filter the data by the injury cause and mechanism (Figure 7-A). Then, group the table by injury cause ICD-10-CM code and injury cause description (Figure 7-B). Sort the table by injury counts in descending order to see which specific codes/injuries contribute most to a given intent-by-mechanism cause group (Figure 7-C). The example below looks at specific ICD-10-CM injury cause codes and descriptions for unintentional falls among children under the age of 18 for the year 2020 (Figure 7).
Figure 7: Suggested analysis to identify specific codes that comprise injury intent-by-mechanism cause groups
2. Injuries during the COVID-19 pandemic
The COVID-19 Pandemic contributed to drastic changes in health outcomes beyond Coronavirus deaths and illness. The Time Series display can provide a quick look at the COVID-19 pandemic’s impact on injuries. First, select the injury outcome of interest and filter the data to the population of interest (but be sure to include 2020 data). The example below looks at injury deaths among all Californians (Figure 8). In the time series display, choose month as the time unit (Figure 8-A). The graph will show counts of injuries by month. Hover over the graph’s data points to see exact time periods and injury counts (Figure 8-B). You may notice considerable changes to injuries during the late winter and early spring of 2020.
Figure 8: Suggested analysis to explore changes in injuries during the COVID-19 pandemic
3. County comparison of injury rates
Comparing injury rates across counties can help determine if a specific county has a relatively high or low injury rate compared to other locations and provide insight on how injuries vary geographically across California. The Bar Chart display can provide that information at a glance.
First, select the injury outcome of interest and filter the data to the population of interest (but be sure to include all counties). The example below looks at pedal cyclist injury hospitalizations among all Californians (Figure 9). In the bar chart display, choose to group the data by county of residence, choose rate as the injury measure, and choose injury measure as the bar order (Figure 9-A). The chart will now rank California counties from those with the highest to lowest injury rates.
Figure 9: Suggested analysis to compare county injury rates
Attribution
EpiCenter was developed by the California Department of Public Health (CDPH) Injury and Violence Prevention Branch (IVPB) with funding from the Centers for Disease Control and Prevention (CDC).
Suggested Citation
California Department of Public Health, Injury and Violence Prevention Branch. (2023, December 15). EpiCenter: California Injury Data Online. Retrieved Month DD, YYYY, from https://skylab4-dev.cdph.ca.gov/epicenter/.
Injury deaths are identified from the California Department of Public Health (CDPH) California Comprehensive Master Death File (CCMDF). The CCMDF includes in-state deaths and deaths of California residents that occurred in other states or jurisdictions. It is derived from the death registration process and includes information from the death certificate, which is provided by informants and clinicians. More information can be found on the CDPH Vital Records Data and Statistics web page.
Injury hospitalizations and emergency department (ED) visits are identified from the California Department of Health Care Access and Information (HCAI) Patient Discharge Data (PDD) and ED Data, respectively. The PDD include records of inpatient discharge from California-licensed hospitals, including general acute care, acute psychiatric, chemical dependency recovery, and psychiatric health facilities. The ED data include records of patient face-to-face encounters with providers at hospitals licensed to provide emergency medical services. If an ED encounter resulted in a same-hospital admission, the ED encounter would be combined with the PDD record and only appear as a hospitalization. More information can be found on the HCAI Data Documentation web page.
Injury Case Definitions
Deaths
Injury deaths are identified using International Classification of Diseases, 10th Revision (ICD-10) codes appearing in the underlying cause of death field. ICD-10 is a coding system used for classifying cause of deaths. The underlying cause of death field contains the ICD-10 code describing “the disease or injury which initiated the causal chain of morbid events leading directly to death or the circumstances of the accident or violence which produced the fatal injury.” In the case of an injury death, the underlying cause of death field must be coded with an external cause-of-injury code (Table 1). The EpiCenter case definition for injury deaths are deaths with any of the ICD-10 external cause of injury codes appearing in the underlying cause of death field. The EpiCenter injury death case definition is consistent with the Centers for Disease Control and Prevention (CDC) recommended surveillance case definition, which is described in detail in its State Injury Indicators Report.
Table 1: ICD-10 external cause of injury codes
Code(s)*
Description
V01-Y36, Y85-Y87, Y89, U01-U03
Injury and poisoning
Hospitalization and ED Visits
Injury hospitalizations and ED visits are identified using ICD-10, Clinical Modification (ICD-10-CM) codes appearing in any of 25 diagnosis fields and 12 external cause of morbidity fields. The ICD-10-CM is a coding system used for classifying diagnoses and reason for visits in all health care settings. Diagnoses fields include a principal diagnosis field, which describes the condition established to be the chief reason for care, as well as up to 24 other diagnoses that describe conditions that coexist or develop during care and affect the treatment received. External cause of morbidity fields describe mechanisms that resulted in the most severe conditions.
The Epicenter case definition for injury ED visits are patient encounters with any of the ICD-10-CM injury diagnosis codes listed in Table 2 appearing in any of the 25 diagnosis or 12 external cause of morbidity fields or any of the ICD-10-CM external cause of injury codes listed in Table 3 appearing in any of the 25 diagnosis fields or 12 external cause of morbidity fields. The EpiCenter injury ED visit case definition is consistent with the CDC recommended surveillance case definition, which is described in detail in National Health Statistics Report Number 164.
Table 2: ICD-10-CM injury diagnosis codes
Code(s)*
Description
S00–S99
Anatomic injuries
T07–T34, R45.88
Foreign bodies, burns, corrosions, frostbite
T36–T50 with a 6th character of 1, 2, 3, or 4. Note: Includes T36.9, T37.9, T39.9, T41.4, T42.7, T43.9, T45.9, T47.9, and T49.9 with a 5th character of 1, 2, 3, or 4 (Intent information for these codes is included in the 5th character and not the 6th).
Poisoning by drugs, medicaments, and biological substances (Includes accidental, intentional self-harm, assault, and underdetermined intents; Excludes adverse effects and underdosing)
T51–T65
Toxic effects of substances nonmedicinal as to source
T66–T76
Other and unspecified effects of external causes
T79
Certain early complications of trauma, not elsewhere classified
O9A.2–O9A.5
Traumatic injuries and abuse complicating pregnancy, childbirth, and the puerperium
T84.04, M97
Periprosthetic fracture around internal prosthetic joint
* Only includes codes with a 7th character of A, B, C or missing (reflects initial encounter, active treatment)
Table 3: ICD-10-CM external cause of injury codes
Code(s)*
Description
V00-V99
Transport accidents
W00–X58
Other external causes of accidental injury
X71–X83
Intentional self-harm
X92–Y09
Assault
Y21–Y33
Event of undetermined intent
Y35–Y38
Legal intervention, operations of war, military operations and terrorism
* Only includes codes with a 7th character of A or missing (reflects initial encounter, active treatment)
The case definition for injury hospitalizations are patient discharges with any of the ICD-10-CM diagnosis codes listed in Table 2 appearing in the principal diagnosis field or any of the ICD-10-CM codes with external cause of injury information listed in Table 4 appearing in any of the 25 diagnosis fields or 12 external cause of morbidity fields.
Table 4: ICD-10-CM codes that contain external cause of injury information (includes all codes from Table 3 and a subset of codes from Table 2)
Code(s)*
Description
V00-V99
Transport accidents
W00–X58
Other external causes of accidental injury
X71–X83
Intentional self-harm
X92–Y09
Assault
Y21–Y33
Event of undetermined intent
Y35–Y38
Legal intervention, operations of war, military operations and terrorism
T14.91, R45.88
Suicide attempt, nonsuicidal self-harm
T15–T19
Effects of foreign body entering through natural orifice
T36–T50 with a 6th character of 1, 2, 3, or 4. Note: Includes T36.9, T37.9, T39.9, T41.4, T42.7, T43.9, T45.9, T47.9, and T49.9 with a 5th character of 1, 2, 3, or 4 (Intent information for these codes is included in the 5th character and not the 6th).
Poisoning by drugs, medicaments, and biological substances
T51–T65
Toxic effects of substances chiefly non-medicinal as to source
T71
Asphyxiation
T73
Effects of deprivation
T74, T76
Adult and child abuse, neglect, and other maltreatment, confirmed or suspected
T75.0–T75.4
Effects of lightning, drowning, and vibration, motion sickness, electrocution
* Only includes codes with a 7th character of A or missing (reflects initial encounter, active treatment)
The EpiCenter injury hospitalization case definition differs from the CDC recommended injury surveillance case definition, which is described in detail in National Health Statistics Report Number 125. The CDC case definition limits injury hospitalizations to those with an injury diagnosis code listed as the principal diagnosis only. This is intended to limit cases to injuries of sufficient severity to warrant hospitalization. Authors of the CDC case definition acknowledges that, “focus on particular types, mechanisms, or intents of injury might require the use of different selection criteria”. To facilitate focus on specific injuries, the EpiCenter case definition is more comprehensive. In addition to hospital visits with an injury diagnosis code listed as the principal diagnosis, it also includes those with an external cause of injury code appearing in any diagnosis or external cause of morbidity field. This expanded EpiCenter case definition is intended to serve those interested in understanding causes of injury, which can inform prevention. For example, many patients hospitalized with a self-harm injury receive a principal diagnosis of a mental health condition. Overlooking these injuries may lead to an underestimate of the role that mental health plays in self-harm injuries.
The EpiCenter case definition is the default, and is called “Comprehensive”. To apply the more conservative CDC case definition, select “Surveillance” under the hospitalization case definition filter.
Additional Inclusion/Exclusion Criteria
Injuries on EpiCenter are limited to California residents with a recorded age between 0 and 119 years (newborn hospital transfers are excluded). Additionally, injury hospitalizations and ED visits are limited to non-fatal dispositions, as fatal injuries are captured in the death data.
Injury Cause Classification
Injuries are classified based on the external-cause-of-injury matrix, which classifies each ICD-10 or ICD-10-CM external cause of injury code by intent (column) and mechanism (row). The specific ICD-10 and ICD-10-CM codes assigned to each intent-by-mechanism cell within the matrix can be found on the CDC’s Tools for Categorizing Injuries using ICD Codes Web Page. Table 5 illustrates the structure of the matrix and identifies injury intent-by-mechanism cells with one or more ICD-10 or ICD-10-CM codes.
Mechanism
Intent
Table 5: External-cause-of-injury Matrix
Unintentional
Self-harm/Suicide
Assault/Homicide
Undetermined
Legal intervention/ War operation
Cut/Pierce
●
●
●
●
●
Drowning/submersion
●
●
●
●
Fall
●
●
●
●
Fire/burn
●
●
●
●
●
Fire/flame
●
●
●
●
o
Hot object/substance
●
●
●
●
Firearm
●
●
●
●
●
Machinery
●
All transportation
●
●
●
●
●
Motor vehicle–traffic (MVT)
●
o
o
o
MVT–Occupant
●
o
o
MVT–Motorcyclist
●
MVT–Pedal cyclist
●
MVT–Pedestrian
●
o
MVT–Other
●
MVT–Unspecified
●
o
Motor vehicle–Nontraffic
o
Pedal cyclist, other
●
Pedestrian, other
●
Other land transport
●
●
●
x
Other transport
●
o
●
●
Natural/environmental
●
o
o
o
Bites/stings, nonvenomous
o
o
Bites/stings, venomous
o
o
o
o
Natural/environmental, other
o
o
o
o
Overexertion
o
o
o
o
Poisoning
●
●
●
●
●
Drug
o
o
o
o
Nondrug
o
o
o
o
o
Struck by/against
●
●
●
x
●
Suffocation
●
●
●
●
o
Other specified
●
●
●
●
●
Other specified, child/adult abuse
o
Other specified, foreign body
o
Other specified, classifiable
●
●
●
●
●
Other specified, not elsewhere classifiable
x
●
●
●
●
Unspecified
x
●
●
x
●
● = valid ICD-10 and ICD-10-CM code(s); x = valid ICD-10 code(s) only; o = valid ICD-10-CM code(s) only; blank cells have no valid codes
Variable Definitions
The following variables are available for filtering and grouping injury data. Click on the variable to view the definition.
YearDeaths: The calendar year of death. Hospitalizations: The calendar year the patient was discharged. ED Visits: The calendar year service was provided to the patient. Age
Deaths: Age (in years) at time of death. Hospitalizations: Age of the patient (in years) at admission. ED Visits: Age of the patient (in years) at time of service.
For grouping purposes, two options in addition to individual years are provided.
Summary groups are commonly used for injury surveillance and include <1, 1-4, 5-9, 10-14, 15-19, 20-24, 25-44, 45-64, 65-84, and 85+ years.
5-year groups start with 0-4 years and continue through 95-99 years; individuals aged 100 years or more are included in a 100+ category.
SexDeaths: The decedent’s biologic sex. “Other/Unknown” is used when sex is not recorded, unknown, or non-binary. Hospitalizations and ED Visits: The patient’s biologic sex. “Other/Unknown” is used when sex is not recorded or in the case of undetermined sex and congenital abnormalities that obscure sex identification.
Race/Ethnicity
Deaths, Hospitalizations, and ED Visits: Normalized race/ethnicity group based on a combination of reported race and ethnicity. Groups are defined as follows:
Hispanic: Hispanic ethnicity of any race
White: Non-Hispanic White
Asian: Non-Hispanic Asian
Black: Non-Hispanic Black
American Indian/Alaska Native: Non-Hispanic American Indian/Alaska Native
Pacific Islander: Non-Hispanic Native Hawaiian or other Pacific Islander
Multiracial: Non-Hispanic and more than one of the five race groups listed above (White, Asian, Black, AI/AN, Pacific Islander)
Other/Unknown: All other Non-Hispanic races and incomplete reporting
Note: For Hospitalizations and ED visits prior to 2019, the multiracial category was not available and Asian and Native Hawaiian/Pacific Islander were grouped together as a single category. For this reason, when filtering or grouping non-fatal injuries by race/ethnicity, it is advised to limit data to either 2019 and later or 2018 and earlier.
Education
Deaths: Decedent’s highest level of education. Only available for those aged 25 years and older. Categories are defined as follows:
Less than high school: 12th grade or less; no diploma
High school: High school diploma or GED
Some college or associate degree: Some college credit, but no degree or associate degree
Bachelor’s degree: Bachelor’s degree
Advanced degree: Master’s, doctorate, or professional degree
Unknown: Unknown or not reported
Hospitalizations and ED Visits: N/A
VeteranDeaths: Whether the decedent ever served in the armed forces. Only available for those aged 18 years and older. Hospitalizations and ED Visits: N/A
County of ResidenceDeaths: County of residence based on decedent’s address or as entered on the death certificate. “N/A (Unknown)” category is used when state residence is reported as California but county of residence is missing or unknown. Decedents with missing or unknown state and county of residence are excluded along with those residing outside California. Hospitalizations and ED Visits: County of residence based on patient-reported ZIP Code. Unhoused patients identified in the data are included under a “N/A (Unhoused)” category. Patients with unknown or missing ZIP codes are excluded along with those residing outside California.
Region of Residence
Deaths, Hospitalizations, and ED Visits: Region of residence. Seven regions defined according to the following county groupings:
Central Coast: Ventura, Santa Barbara, Santa Cruz, San Luis Obispo, Monterey, and San Benito counties
Greater Bay Area: Santa Clara, Alameda, Contra Costa, San Francisco, San Mateo, Solano, Sonoma, Marin, and Napa counties
Los Angeles County: Los Angeles County
Northern and Sierra Counties: Butte, Shasta, Humboldt, Del Norte, Siskiyou, Lassen, Modoc, Trinity, Mendocino, Lake, Tehama, Glenn, Colusa, Sutter, Yuba, Nevada, Plumas, Sierra, Tuolumne, Calaveras, Amador, Inyo, Mariposa, Mono, and Alpine counties
Other Southern California: Orange, San Diego, San Bernardino, Riverside, and Imperial counties
Sacramento Area: Sacramento, Placer, Yolo, and El Dorado counties
San Joaquin Valley: Fresno, Kern, San Joaquin, Stanislaus, Tulare, Merced, Kings, and Madera counties
Note: Unknown county of residence (deaths) or unhoused patients (hospitalizations and ED visits) are included under a separate “N/A” category.
Hospital/ED Location, CountyDeaths: N/A Hospitalizations and ED Visits: The county where the facility is located.
Hospital/ED Location, Region
Deaths: N/A Hospitalizations and ED Visits: Seven regions defined according to the following county groupings:
Central Coast: Ventura, Santa Barbara, Santa Cruz, San Luis Obispo, Monterey, and San Benito counties
Greater Bay Area: Santa Clara, Alameda, Contra Costa, San Francisco, San Mateo, Solano, Sonoma, Marin, and Napa counties
Los Angeles County: Los Angeles County
Northern and Sierra Counties: Butte, Shasta, Humboldt, Del Norte, Siskiyou, Lassen, Modoc, Trinity, Mendocino, Lake, Tehama, Glenn, Colusa, Sutter, Yuba, Nevada, Plumas, Sierra, Tuolumne, Calaveras, Amador, Inyo, Mariposa, Mono, and Alpine counties
Other Southern California: Orange, San Diego, San Bernardino, Riverside, and Imperial counties
Sacramento Area: Sacramento, Placer, Yolo, and El Dorado counties
San Joaquin Valley: Fresno, Kern, San Joaquin, Stanislaus, Tulare, Merced, Kings, and Madera counties
Death/Admission/Service MonthDeaths: The calendar month when the death occurred. Hospitalizations: The calendar month when the patient was admitted to the hospital. ED Visits: The calendar month when the patient encounter occurred.
Death/Admission/Service Day of WeekDeaths: The day of the week when the death occurred. Hospitalizations: The day of the week when the patient was admitted to the hospital. ED Visits: The day of the week when the patient encounter occurred.
Injury Case Definition
Deaths and ED Visits: N/A (only one case definition is available) Hospitalizations: The criteria used to identify if a hospitalization was injury related.
Comprehensive (default) includes hospitalizations with an injury diagnosis ICD-10-CM code listed as the principal diagnosis or an ICD-10-CM code with external cause of injury information appearing in any diagnosis or external cause of morbidity field.
Surveillance The more conservative CDC injury surveillance case definition is limited to hospitalizations with an injury diagnosis code listed as the principal diagnosis only.
For more information, see the [injury case definitions] section.
Injury IntentDeaths, Hospitalizations, and ED Visits: The intent of the injury based on classification of the external cause of injury ICD-10 or ICD-10-CM code within the external-cause-of-injury matrix. For more information, see the injury cause classification section.
Injury MechanismDeaths, Hospitalizations, and ED Visits: The mechanism of the injury based on classification of the external cause of injury ICD-10 or ICD-10-CM code within the external-cause-of-injury matrix. For more information, see the injury cause classification section.
Injury Cause ICD-10/ICD-10-CM CodeDeaths: The specific ICD-10 code listed as the underlying cause of death and which corresponded to an external cause of injury. This code was used to classify the injury death according to the external cause of injury matrix. Hospitalizations and ED Visits: The specific ICD-10-CM Code that corresponds to an external cause of injury and was used to classify the injury hospitalization/ED visits according to the external cause of injury matrix. Up to the first 6 digits of the code are included. Missing values for this variable mean that the hospital visit was identified as an injury through an injury diagnosis ICD-10-CM code only. For example, a code for a broken arm but no additional code describing what caused the bone to break.
Injury Cause DescriptionDeaths, Hospitalizations, and ED Visits: The text description of the Injury Cause ICD-10 or ICD-10-CM Code. This variable is only available in the custom table view for grouping purposes.
Hospital Length of StayDeaths and ED Visits: N/A Hospitalizations: Total number of days from admission date to discharge date, categorized into the following groups: Same day/Overnight, 2 days, 3-4 days, 5-7 days, and more than 1 week.
Disposition
Deaths: N/A Hospitalizations and ED Visits: The consequent arrangement or event ending a patient’s stay in the hospital or ED visit. HCAI disposition categories are aggregated into 5 categories as follows:
Treat and release: Discharged to home or self care (routine discharge); Discharged/Transferred home under the care of organized home health service organization in anticipation of covered skilled care; Left against medical advice or discontinued care; Discharged/Transferred to court/law enforcement; Discharged home with hospice care
Transfer-Acute Care Hospital: Discharged/Transferred to a short-term general hospital for inpatient care; Discharged/Transferred to a designated cancer center or children’s hospital; Discharged/Transferred to a critical access hospital (CAH)
Transfer-non-acute care hospital: Discharged/Transferred to a skilled nursing facility (SNF) with Medicare certification in anticipation of covered skilled care, Discharged/Transferred to a facility that provides custodial or supportive care, Discharged/Transferred to a federal health care facility, Discharged to a medical facility with hospice care, Discharged/Transferred to a hospital-based Medicare approved swing bed, Discharged/Transferred to an inpatient rehabilitation facility (IRF) including rehabilitation distinct part unit of a hospital, Discharged/Transferred to a Medicare certified long-term care hospital (LTCH), Discharged/Transferred to a nursing facility certified under Medicaid (Medi-Cal), but not certified under Medicare, Discharged/Transferred to another type of healthcare institution not defined elsewhere on this code list
Transfer-psychiatric hospital: Discharged/Transferred to a psychiatric hospital or psychiatric distinct part unit of a hospital;
Other/unknown: all other HCAI categories
Expected Payer
Deaths: N/A Hospitalizations and ED Visits: The type of entity or organization expected to pay the greatest share of the patient’s bill. EpiCenter expected payer categories are aggregated from HCAI payer categories as follows:
Hospitalization payer categories:
Medicare: Medicare
Medi-Cal: Medi-Cal
Other Government: County Indigent Programs, Other Government
Private Insurance: Private Coverage, Other Payer
Uninsured: Self-Pay
Other/Unknown: Workers’ Compensation, Other Indigent, Other Payer, not reported
ED payer categories:
Medicare: Health Maintenance Organization (HMO) Medicare Risk, Medicare Part A, Medicare Part B
Medi-Cal: Medicaid (Medi-Cal)
Other Government: Other Non-Federal Programs, CHAMPUS (TRICARE), Other Federal Program, Title V, Veterans Affairs Plan
Private Insurance: Preferred Provider Organization (PPO), Point of Service (POS), Exclusive Provider Organization (EPO), Automobile Medical, Blue Cross / Blue Shield, Commercial Insurance Company, Health Maintenance Organization
Uninsured: Self-Pay
Other/Unknown: Disability, Workers’ Compensation Health Claim, other, not reported
Unit of Analysis
For injury deaths, counts provided on EpiCenter represent individual California residents. Each injury death is assigned to one mutually exclusive injury intent-by-mechanism cause category.
For non-fatal injury hospitalizations and ED visits, counts provided on EpiCenter are not equal to individual California residents. The same person could experience two or more separate injury events that required a hospitalization or ED visit. Each hospitalization or ED visit for that same person would be counted as a separate injury. For example, a person who was hospitalized for a fall, was discharged to go home, and then fell again two weeks later and was hospitalized would be counted as two separate hospitalization injuries.
Additionally, injury ICD-10-CM codes may appear in 37 fields (25 diagnosis fields and 12 external cause of morbidity fields). This means a single hospitalization or ED visit could include multiple ICD-10-CM external cause of injury codes that correspond to different injury intents and mechanisms. For example, a person could be treated at the ED for an assault cut/pierce injury and an unintentional fall injury during the same visit. EpiCenter will count this single visit as multiple injuries when grouped by intent or mechanism. If injuries are grouped by intent, this single ED visit would be counted twice: once as an assault injury ED visit and once as an unintentional injury ED visit. Likewise, if injuries are grouped by mechanism, this single ED visit would also be counted twice: once as a cut/pierce injury ED visit and once as a fall injury ED visit. In all other instances it would be counted as a single injury ED visit.
Data years 2016 – 2019 use the Vintage 2020 release (2021.7.14).
Data years 2020 – 2022 use the Vintage 2023 release (2023.7.19). Please note: prior to December 2023, rates for data years 2020 and 2021 were calculated using the Vintage 2020 release. Rates currently shown for these years may differ from those that appeared on EpiCenter prior to December 2023.
The P-3 dataset includes population projections by year, age, sex, race/ethnicity, and county. Rates are not available for populations not included in this dataset, including education level, veteran status, expected payer (i.e., insurance type). Rates are also not available for other/unknown categories of populations included in the dataset (e.g., other/unknown sex, unhoused Californians). Additionally, rates are not available for hospital/ED facility county or region location because the source population (i.e., catchment area) is not clearly defined.
Due to differences in how race/ethnicity is reported in the population and injury data, caution should be used when interpreting rates involving race/ethnicity.
Because injuries are events that occur over time, incidence rates are used and expressed as injuries per 100,000 person-years. Person-years are the population multiplied by the number of years of observation. Incidence rates can be conceptualized as the number of events per 100,000 persons, per year. A thorough explanation of incidence rates can be found in Tenny & Boktor’s, “Incidence” StatPearls Article.
Limitations
The injury data presented on EpiCenter are intended to provide a comprehensive count of injuries in California. There are, however, important limitations:
Deaths
Injuries are identified through ICD-10 codes in the underlying cause of death field only. They do not include deaths where an injury was an intermediate or contributory cause of death. For example, if a person had a heart attack while driving and was subsequently fatally injured in a fall, the death would not be included because the heart attack would be considered the underlying cause of death.
Data come from death certificate information provided by informants and clinicians and may be subject to error.
Injury deaths are limited to California residents. They do not include injury deaths to non-residents that occurred in California.
Hospitalization and ED Visits
The data only capture injuries treated at state-licensed hospitals and emergency medical services facilities. They do not include injuries treated in the outpatient setting or at federally licensed facilities, such as Veterans Affairs (VA) hospitals. They also do not capture injuries that go untreated.
Injuries are identified through ICD-10-CM code, and are therefore only as accurate as the medical coding used to populate the data. Injuries treated at state-licensed facilities may be missed or misclassified if not accurately coded.
Beginning in 2019, the number of external cause of morbidity fields in the non-fatal hospitalization and ED visit data was expanded from 5 to 12. This may result in more injuries being recorded starting in 2019.
The data are limited to California residents treated in California. They do not include injuries to non-residents treated in California or injuries to California residents treated elsewhere.
Finally, injury counts <11 are suppressed in accordance with the California Health and Human Services data de-identification guidelines.
Injury data are updated annually upon receipt of all source data files, usually in December.
Where do I go for pre-2016 injury data?
Injury data prior to 2016 are still available on the legacy EpiCenter site. In the fourth quarter of 2015, the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) coding system replaced the ICD-9-CM coding system. These codes represent health conditions and are used to identify and classify injuries treated in the hospital or ED. The ICD-10-CM update resulted in changes to the way injuries were identified and classified that were not readily compatible with ICD-9-CM. Due to this coding system update, a new EpiCenter site was created and the original, legacy site was retired.
Because of the transition from the ICD-9-CM to ICD-10-CM coding system, comparisons of non-fatal injury hospitalizations and ED visits before and after 2015 are discouraged. However, there were no changes to the ICD-10 coding system used for fatal injury identification and classification. Injury deaths before and after 2015 can be compared.
Which hospital case definition should I use?
For injury hospitalizations, EpiCenter gives the option of applying two different case definitions: comprehensive and surveillance. The comprehensive case definition is the default and includes hospitalizations with an injury diagnosis ICD-10-CM code listed as the principal diagnosis or an ICD-10-CM code with external cause of injury information appearing in any diagnosis or external cause of morbidity field. This comprehensive case definition should be used to capture hospitalizations with any mention of an injury cause. It is intended to inform prevention efforts that focus on understanding causes of injury.
The surveillance case definition is limited to hospitalizations with an injury diagnosis code listed as the principal diagnosis only. This definition excludes cases where the injury alone may not warrant hospitalization. It should be used to exclude injuries that may not be treated in the hospital if not for some other health condition. Because it is consistent with CDC recommendations, it should also be used for comparison to other states or jurisdictions that use the CDC-recommended case definition.
As an example, a patient seeking medical treatment for a fall may be diagnosed and hospitalized with an infection that contributed to or complicated the fall. If the infection was listed as the principal diagnosis, then the hospitalization would be included in the comprehensive case definition but would be excluded from the surveillance case definition.
For injury deaths and ED visits, only one case definition is available, which is consistent with CDC recommendations. For more information, see the injury case definitions section of the EpiCenter Methods page.
Would someone who is treated at the ED then admitted to the hospital appear in both data?
If an ED visit resulted in admission to the hospital at the same facility, the ED visit would be combined with the hospitalization record and only appear as a hospitalization. It may, however, be possible for a patient with an injury to be treated at an ED, then transferred to a different hospital. In this case, the same injury may appear in both the ED visit and hospitalization data.
Injuries treated in the ED or hospital with a fatal patient disposition are excluded and would only appear in the death data.
The injury rates for years 2020 and 2021 are different from what I saw on EpiCenter previously. Why did they change?
In an effort to use the most accurate population data to calculate injury rates, sometimes rates will be revised when new population projections become available. Rates for data years 2020 and 2021 were updated on EpiCenter in December 2023 using the latest population projections from the California Department of Finance, which were released in 2023 and are based on 2020 U.S. Census results.
Why are the number of injury deaths on the legacy EpiCenter different?
The legacy EpiCenter site contains death injury data through 2020. The number of injury deaths that appear on the legacy EpiCenter site differ slightly from the new EpiCenter site for years 2016 through 2019. This is because upgrades to the process for applying exclusion criteria were applied retrospectively to those years of data when creating the new EpiCenter site. These upgrades better identified California residents and those with known ages <1 year (EpiCenter data exclude non-residents and those with an unknown age). The upgrades resulted in a net change of -32 injury deaths in 2016, -41 injury deaths in 2017, +3 injury deaths in 2018, and +1 injury deaths in 2019.
Sometimes the sum of injury hospitalizations or ED visits is greater than the total number of injuries shown. Why is this?
When non-fatal injury hospitalizations and ED visits are grouped by injury cause variables (intent, mechanism, ICD-10-CM code, or code description), the sum of the groups may be larger than the total number of unique visits shown at the top of the page along with the filter description. This is because injury ICD-10-CM codes, which are used for identifying and classifying injuries, may appear in up to 37 fields in the data. This means a single hospitalization or ED visit could include multiple ICD-10-CM codes that correspond to different injury causes. For example, a person could be treated at the ED for an assault cut/pierce injury and an unintentional fall injury during the same visit. EpiCenter will count this single visit twice when grouped by intent or mechanism. If injuries are grouped by intent, this single ED visit would be counted once as an assault injury ED visit and once as an unintentional injury ED visit. Likewise, if injuries are grouped by mechanism, this single ED visit would also be counted once as a cut/pierce injury ED visit and once as a fall injury ED visit. In all other instances it would be counted as a single injury ED visit.
What are person-years?
Person-years are the population multiplied by the number of years of observation. They are used to calculate incidence rates, which are the rate of new events that occur during a specified period for the population at risk for the event. The injury incident rates shown on EpiCenter can be conceptualized as the number of injuries per 100,000 persons, per year. A thorough explanation of incidence rates can be found in Tenny & Boktor’s, “Incidence” StatPearls Article.
Rows with injury counts that appear blank have <11 injuries and are suppressed for data de-identification purposes.
Rows with injury rates that appear blank do not have appropriate population data available for rate calculation.
Rates for data years 2020 and 2021 were updated in December 2023 using the latest population projections from the California Department of Finance and may differ from rates that appeared on EpiCenter previously.
Injury counts <11 are not graphed for data de-identification purposes.
Injury rates are not graphed when appropriate population data for rate calculation are unavailable.
Rates for data years 2020 and 2021 were updated in December 2023 using the latest population projections from the California Department of Finance and may differ from rates that appeared on EpiCenter previously.
Injury counts <11 are not graphed for data de-identification purposes.
Injury rates are not graphed when appropriate population data for rate calculation are unavailable.
Rates for data years 2020 and 2021 were updated in December 2023 using the latest population projections from the California Department of Finance and may differ from rates that appeared on EpiCenter previously.
Rows with injury counts that appear blank have <11 injuries and are suppressed for data de-identification purposes.
Rows with injury rates that appear blank do not have appropriate population data available for rate calculation.
Rates for data years 2020 and 2021 were updated in December 2023 using the latest population projections from the California Department of Finance and may differ from rates that appeared on EpiCenter previously.
Starting in 2019, race/ethnicity coding was expanded to include Multiracial as a category and separate Asian and Pacific Islander into two categories. When grouping by race/ethnicity, it is advised to limit data to either 2019 and later or 2018 and earlier.
Injury counts <11 are not graphed for data de-identification purposes.
Injury rates are not graphed when appropriate population data for rate calculation are unavailable.
Rates for data years 2020 and 2021 were updated in December 2023 using the latest population projections from the California Department of Finance and may differ from rates that appeared on EpiCenter previously.
Starting in 2019, race/ethnicity coding was expanded to include Multiracial as a category and separate Asian and Pacific Islander into two categories. When grouping by race/ethnicity, it is advised to limit data to either 2019 and later or 2018 and earlier.
Injury counts <11 are not graphed for data de-identification purposes.
Injury rates are not graphed when appropriate population data for rate calculation are unavailable.
Rates for data years 2020 and 2021 were updated in December 2023 using the latest population projections from the California Department of Finance and may differ from rates that appeared on EpiCenter previously.
Starting in 2019, race/ethnicity coding was expanded to include Multiracial as a category and separate Asian and Pacific Islander into two categories. When grouping by race/ethnicity, it is advised to limit data to either 2019 and later or 2018 and earlier.
Rows with injury counts that appear blank have <11 injuries and are suppressed for data de-identification purposes.
Rows with injury rates that appear blank do not have appropriate population data available for rate calculation.
Rates for data years 2020 and 2021 were updated in December 2023 using the latest population projections from the California Department of Finance and may differ from rates that appeared on EpiCenter previously.
Starting in 2019, race/ethnicity coding was expanded to include Multiracial as a category and separate Asian and Pacific Islander into two categories. When grouping by race/ethnicity, it is advised to limit data to either 2019 and later or 2018 and earlier.
Injury counts <11 are not graphed for data de-identification purposes.
Injury rates are not graphed when appropriate population data for rate calculation are unavailable.
Rates for data years 2020 and 2021 were updated in December 2023 using the latest population projections from the California Department of Finance and may differ from rates that appeared on EpiCenter previously.
Starting in 2019, race/ethnicity coding was expanded to include Multiracial as a category and separate Asian and Pacific Islander into two categories. When grouping by race/ethnicity, it is advised to limit data to either 2019 and later or 2018 and earlier.
Injury counts <11 are not graphed for data de-identification purposes.
Injury rates are not graphed when appropriate population data for rate calculation are unavailable.
Rates for data years 2020 and 2021 were updated in December 2023 using the latest population projections from the California Department of Finance and may differ from rates that appeared on EpiCenter previously.
Starting in 2019, race/ethnicity coding was expanded to include Multiracial as a category and separate Asian and Pacific Islander into two categories. When grouping by race/ethnicity, it is advised to limit data to either 2019 and later or 2018 and earlier.
