# Presentation: 690440

## Measuring Injury Using the National Health Interview Survey

**Margaret Warner, PhD****	**
**Lois A. Fingerhut, MA**
**Pat Barnes, MA**

## Location of injury and poisoning data

** ****Injury Episode file**
** ****Injury Verbatim file**
** ****Poison Episode file**
** ****Person file**

## Injury episode file

**For each person:**
** ****Up to 4 injury episodes**
**For each episode:**
** ****Up to 4 ICD-9-CM diagnosis codes**
** ****Up to 3 ICD-9-CM external cause codes**
** **

## Available data in the Injury Episode file

** ****External cause (ICD-9-CM)**
** ****Injury diagnoses (ICD-9-CM)**
** ****Place of occurrence**
** ****Activity**
** ****Resulting limitations**
** ****Detail on certain causes (e.g. mv crashes, falls)**

## Injury episode file

**Injury episode file**

## Poisoning episode file

** ****Contains no ICD-9-CM codes or            E-codes**
** ****Contains 47 episodes coded as ****	****“****Allergic/adverse reaction to ****	****medical or other substance****” or ****	****“****Something else – ****not**** poisoning****”**

## Available data in the Poisoning Episode file

** ****Cause of poisoning**
** ****Call to poison control center**

## Available data in both injury and poisoning files

** ****Date of episode**
** ****Hospitalization**
** ****Days out of school**
** ****Days out of work**
** ****Time elapsed between episode and interview**

## Injury section–Person file

** ****Contains summary information ****	****about injury and poisoning ****	****episodes**
** ****Annual estimates can only be ****	****made on variables ****INJCT**** and ****	****POICT**

## How do I put the data together?

## Injury and poisoning episode,  and injury verbatim files

** ****Contain ****only**** injury or ****	****poisoning information and ****	****unique identifiers**
** ****Must be linked to the person ****	****file to obtain sociodemographic ****	****variables, design variables, etc.**

## Episode and person based files

**Episode based:  A person will appear in these files as many times as he/she has a unique episodes **
**Person based:  A person will appear in this file only once **

## Concatenating injury and poisoning episode files

**Injury**

**Poisoning**

**+**

**= Missing data, questions not found in both files**

**Injury**

**Poisoning**

## Merging injury/poisoning episode file and person file

**+**

**Person**

**Injury**

**Poisoning**

**= Missing data, questions not found in both files**

## Merged injury/poisoning episode file and person file

**Merged injury/poisoning episode file and person file**

**Injury**

**Poisoning**

**Person**

**= Missing data, questions not found in both files**

## Episodes and Conditions

** ****Episode = ****Event that caused the condition (e.g. fall down stairs)**
** ****Conditions = physical harm resulting from the injury episode (e.g. broken leg, bruised arm)**

## Creating condition filesInjury

**ICD9_1**

**ICD9_2**

**ICD9_3**

**ICD9_4**

**Injury Episode with ICD9_1 ICD9_2 ICD9_3 ICD9_4**

## Creating condition filesPoisoning

**Poisoning episode**

**Poisoning condition**

**=**

## Concatenating injury and poisoning condition files

**Poisoning**

**+**

**Injury conditions**

**Injury conditions**

**Poisoning conditions**

**= Missing data, questions not found in both files**

## What Can I Do With the Data?

## Handout

** ****Using SAS to manipulate the injury and poisoning data**
** ****Example SAS programs for concatenating and merging the files**

## Analyzing the injury and poisoning data

** ****Estimates of frequency**
** ****Percent distributions**
** ****Rates**
** ****Standard errors**

## Calculating annual estimates

** ****Annual est = ****(variable)(4)(WTFA)**
** ****Annual estimates of episodes and conditions can be calculated.**
** ****Annual estimates of the number of persons injured ****cannot**** be calculated due to the 3 month reference period.**

## Standard Errors (SE)

** ****SE of the injury/poisoning rate ****	****for males and females**
** ****SE of the injury/poisoning rate ****	****for specified racial groups**

## Estimates of frequencyExamples

** ****Number of episodes resulting ****	****from specific causes**
** ****Number of injury/poisoning  ****	****episodes by sex**
** ****Number of injury/poisoning ****	****episodes by mechanism**

## Results

## Rates Examples

** ****Annual injury/poisoning rates ****	****for males and females **
** ****Annual injury/poisoning rates ****	****by mechanism**
** ****Annual rate of falls for females ****	****over 65 years of age**

## Injury and poisoning episode rates

**Injury and poisoning ****episode rates**

**Age in years**

**Episodes per 1,000 population**

- 95% CI

## Age adjusted injury episode rates by mechanism of injury

## Age adjusted condition rates by type of injury, 1997

## PercentagesExamples

** ****Percent of episodes resulting ****	****from specific causes**
** ****Percent of poisoning ****	****episodes in which a poison ****	****control center was called**
** ****Percent of injury episodes that ****	****occurred in the home**

## Percent of injury episodes by place of injury, 1997

**Percent of episodes**

- Persons could indicate up to two places per episode.

## Work-related injuries

** ****Injury episode file:**
**	**** ****Activity at the time of injury=**
**Working at a paid job**
** ****Sample person file:**
**	****Occupation and industry **

## Percent of injury episodes by activity, 1997

**Percent of episodes**

- Persons could indicate up to two places per episode.

## Injury verbatim file

**  ****Responses recorded by the interviewer:**
** ****How the injury occurred**
** ****Body part injured**
** ****Nature of injury**
**  ****Text file linkable to other files**

## Available data in injury verbatim

** ****How the injury occurred           ****	****(up to 336 characters)****	**
** ****Up to 4 body parts injured    ****	****(up to 34 characters each)**
** ****Up to 4 nature of injuries       ****	****(up to 44 characters each)**

## Injury verbatim file

** ****Edited only for confidentiality**
** ****Grammatical and/or spelling ****	****errors were not corrected**

## Uses of injury verbatim

** ****NCHS used to code ICD-9-CM diagnoses and external causes**
** ****Code according to other classification schemes (e.g. BLS, ICECI, etc)**
** ****Text search for words of interest**
** ****In-depth analysis of ICD-9-CM categories**

## Check sample size

**Analysts should be cautioned ****	****against making estimates ****	****based on small numbers of ****	****observations.**

## Verbatim textExample

**Cause of injury:        ****.   ****                     **
**Part of body:**
**Type of injury:**

***“******While <in-line skating>, fell on thumb.”***
***“******Right thumb”***
***“******Broken”***

## Examples of verbatimMachinery related injuries (E919)

** “****He was at home working on his table saw and accidentally ran his left thumb through the machine lengthwise.” (table saw, n=8) **
**  “****Forklift extension came loose dropping on right foot at work”  (forklift, n=3)**

## Contact for questions related to injury data or injury classification issues:MWarner@cdc.gov