# Presentation: 248190

## Using Linked Data to Examine Injury and Disability

- Beth Rasch and Chris Cox
- National Center for Health Statistics

- 2006 ICE meeting

## Background

- Research is limited on the
- 	injury       disability pathway, particularly large scale studies
- Determining the temporal relationships between injury and disability is challenging

## Temporal relationships

- Ideally, we would like to know about:
- the level of functioning prior to the injury event
- the injury event
- the level of functioning following the injury event

**Pre-injury**
**functioning**

**Injury**

**Post-injury**
**functioning **
**over time**

## Data gap

- In the U.S., national data sources that include longitudinal information on injury and disability are limited
- Data availability may be different in other countries
- Record linkage can begin to address this gap

## Purpose of presentation

- Identify data needs for studying injury / disability
- Begin to examine the potential to study injury / disability using longitudinal survey data and linked administrative data sources

## What is record linkage?

- Record linkage combines information for the same entity or individual from a variety of sources
- Respondent information from health surveys can be linked to administrative records (e.g. vital statistics, receipt of disability benefits, etc.)

## Benefits of record linkage

- Increases analytic potential of health surveys for epidemiologic research
- Increases accuracy and detail of data collected
- Augments available information
- Provides longitudinal component to survey data
- Reduces cost (eliminates re-contact)

## Data needs

**Pre-injury**
**functioning**

**Injury**

**Post-injury**
**functioning **
**over time**

## Example: Linked survey data

- NHIS and MEPS are health surveys
- MEPS is a nationally representative subsample of NHIS households
- Annual files to link NHIS to MEPS available on request from AHRQ
- Longitudinal weight files available on AHRQ website
- http://meps.ahrq.gov/Puf/PufSearch.asp?

## Key analytic variables: MEPS and NHIS

- _Functioning_
- Self-reported function in ADLs, IADLs, movement, seeing/hearing, cognition, work, social activities
- Use of assistive equipment
- Time lost from usual activities

- _Injury_
- ICD diagnosis code
- Onset
- Location
- Cause of injury
- Received treatment
- Recovery (MEPS)
- Seriousness of injury (MEPS)

**Notes:**
Demographic data (both surveys)
Activity in which the respondent was engaged when the accident occurred (NHIS) 
Detailed data on health care utilization and costs (MEPS)

## MEPS sample design

**1995 NHIS**

- Round 1  Round 2       Round 3   Round 4    Round 5

- Jan

- Round 1    Round 2    Round 3

- Jan

- Jan

- Dec

**MEPS, Panel 2, 1997-1998**

- 1996

- 1997

- 1998

**MEPS, Panel 1, 1996-1997**

**1996 NHIS**

## Examining disability after injury

- Identify functioning (adults) in NHIS
- Identify injuries in Round 1 of MEPS
- Determine change in functioning in Rounds 2-5 of MEPS
- All indicators are not available for each round

**Notes:**
Serious psychological distress measure also available
Can identify comorbid conditions in R1 in order to predict disability in subsequent rounds
MEPS has a wealth of data on healthcare utilization and expenditures

## Example: Linkage with administrative data

- 1994-1998 NHIS linked with SSA Master Beneficiary Records from 1962-2003
- Access to restricted files through NCHS Research Data Center
- 	Note: NHIS injury data differs before and after 1997

## Key analytic variables: SSA

- Benefit history
- Applications for disability benefits
- Program eligibility
- Benefit amount
- Payment status
- Disabling condition

## Temporal relationships

- Application
- for benefits
- and program
- eligibility
- (1962-2003)

- 1994-1998
- NHIS

**Injury event**

**Disability status **
**after injury**

- No

- Yes

- Application
- for benefits
- and program
- eligibility
- (1962-2003)

- Yes

- No

- Yes

- No

**History **
**of disability**

**Notes:**
Identify injuries from NHIS
Identify disability status (program eligibility) in SSA records preceding NHIS year of interest (year of injury) 
For those who were not eligible for disability benefits prior to injury, determine program eligibility after injury in SSA records following the injury year
Note: Condition causing disability can be determined 

## Temporal relationships

- 1995 NHIS

- 1996 MEPS
- Round 1

**Injury event**

**Disability **
**status **
**after injury**

- Yes

- No

- Application
- for benefits
- and program
- eligibility
- (1962-2003)

- No

- Yes

- Yes

- No

**History **
**of disability**

**Benefit **
**status**

- 1996 MEPS
- Rounds 2-5

- Yes

- No

## Summary

- Linked files provide a longitudinal aspect to survey data, offering additional options to study the injury       disability pathway
- Users need to be aware of the unique analytic issues encountered when using linked files