E Codes in Arizona

From Summer 1995
Volume II, Number 2

E codes have proved an invaluable resource for assessing motor vehicle-related injury problems as well as designing programs to reduce these injuries.

Injury Epidemiologist Pamela Goslar of the Arizona Department of Health Services gives her account of a project in which public health and emergency medical service agencies used E codes to identify and address an important injury problem.

The Arizona Governor's Spinal and Head Injury Trust Fund receives a portion of our state's speeding ticket fines for use in head and spinal cord injury primary prevention programs. We collaborated with the trust fund to help develop a primary prevention program. We wanted to target an intervention where it would be the most effective and efficient--where it would get the most bang for the bucks. We wanted to know in which geographic area and on what age group we should concentrate.

Using N [Nature of Injury] codes, we pulled all of the injuries from the health services department hospital discharge database from 1988 through 1991. Then we used E [External Cause of Injury] codes to look at the four most frequent causes of injury [among the spinal and head injuries identified by the N codes].

We have seven level-one trauma centers in our state. We also have a very good trauma society. Our medical records technicians do a great job of recording E codes. And our hospitals do a very good job of including E codes in the hospital discharge data.

The causes were what you would expect: motor vehicle crashes, falls, interpersonal violence, and other (unspecified injuries). We were especially interested in head injuries. So we analyzed the data by county and age group. We compared each county age group rate with the state to see which counties showed significantly higher rates among particular age groups for particular types of injuries. The result: motor vehicle crashes were the top cause of hospitalization from head injuries. And Pima County had higher rates than the rest of the state for age groups 10-24, 30-34, and above 55.

The next step was to refine our analysis of what was happening in Pima County. These were pretty broad categories. We wanted to be much more specific. We contracted with the Arizona Emergency Medicine Research Center to evaluate local data sources that would give us more specific information. Dr. Terry Valenzuela is the medical director of the Tucson Fire Department. Several years ago he instituted the practice of recording E codes in the ambulance run data. So we could go into the Tucson Fire Department EMS data and pull all motor vehicle-related injuries. Because they also used N codes, we could then pull all of the records of head injuries resulting from motor vehicle crashes. We could look at the fire department's data on these incidents for more specific information, like where the crash took place.

We looked at the Tucson data and were able to pinpoint the 10-19 year olds as our highest risk population. The Tucson Fire Department offered to do a seat belt intervention for that age group. We couldn't do every school in the city. In order to target schools, we decided to use the assumption that motor vehicle crashes happen within 10 miles of home. We thought if we could geographically pinpoint crashes, it would tell us where there's a cluster, and we could target that high school. So we took a map and, using the records we had pulled by E code and N code, indicated where there had been a crash in which someone received a head injury. We used different-colored dots and symbols to indicate whether the individuals involved were in our target age group and whether they wore seat belts. It appeared that seat belts were an issue.

First we did all crashes, regardless of the age of the persons injured. We found some clusters. One was right by the first freeway off-ramp coming into Tucson. Then we did the same thing with our targeted group--the 10-19 year olds. And we didn't find any clusters. We did have a band of crashes running across town. I'm not familiar with Tucson, so I took the data down to the Tucson Fire Department. They just laughed. We had outlined the kids' cruising pattern. You could see where it started and where it ended.

It didn't help us target schools, but it showed that we needed to do something. Two high schools asked the fire department to do an intervention. They have chosen some interventions and are asking the kids what they like to see happen. These include a mock car crash and SADD and MADD programs. My favorite is "ghost day." Every 30 minutes a student is randomly chosen to represent a traffic fatality, given a special T-shirt indicating that he or she is a "ghost," and not allowed to talk to the other kids. At the end of the day, they have an assembly about automobile safety. The kids are going to help choose the interventions.

We are also going back to the original run sheets and pulling the police department accident reports to see if we can identify what leads to crashes in this cruising area. We may work with the Tucson Police Department and request additional enforcement during certain hours.

It's a really interesting project. It's really exciting to see it unfold. But without E codes, we could not have identified the problem. And without E codes, we would have no idea if we make a difference. Have we reduced the number of motor vehicle crash injuries? Who knows if you don't have E codes.

Now that we've shown that the Tucson Fire Department database can be used in this way, the University of Arizona Medical Center and the Tucson Medical Center are going to be evaluating Tucson's bicycle helmet ordinance using the Tucson Fire Department database and their own hospital discharge data.

I wish people really understood how important E codes are and how much information they can give you.

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Other Information Available On-line about E codes:
E Codes Introduction
E Codes: The Missing Link in Injury Prevention
Commonly Asked Questions About E Codes
E Codes (An article originally published in Building Bridges)
Building Bridges Building Bridges Home Page

Revised: March 16, 1999

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