Utilization of State-Wide Hospital Separations Data and the Injury Impairment Scale to Assess the Incidence of Spinal Cord Injury Arising from Motor Vehicle Traffic Crashes

Abstract

The objectives of this study were to determine whether routine state-wide hospitalization data can be used for population level surveillance of the incidence of spinal cord injury (SCI) from motor vehicle traffic crashes (MVTCs) and to verify the coverage of the Australian Spinal Cord Injury Register. A method was developed to identify new injury incidents from routine South Australian hospitalization data. Mapping software was then used to derive the Abbreviated Injury Scale (AIS) and Injury Impairment Scale (IIS) codes for each incident case of spinal injury using the principal diagnosis code on the hospital data file. IIS code values in the range from 3 to 6 were considered to be comparable with the SCI coding criteria utilized by the Australian Spinal Cord Injury Register (ASCIR) which were based on the criteria of the American Spinal Injury Association. The number of estimated new incident cases of SCI based on the IIS coding of hospitalization data was compared with the actual number reported from the ASCIR. The case numbers were highly comparable overall and also by time and age group suggesting that the coverage of the ASCIR was very high. The results of the study support use of the IIS for estimating incident case numbers of MVTC-related SCI from routine state-wide hospitalization data. If routine hospital separations data elsewhere were suitable for the purpose and the IIS also proves to be applicable to non-MVTC-related SCI, the incidence of SCI could be monitored in state and national populations using the IIS and this could provide an alternative data source where registers of SCI do not exist. In addition, the IIS provides a means to assess coverage where registers do exist.

Keywords:

• Injury Impairment Scale
• Spinal Cord Injury
• Surveillance Methods
• ICDMAP-90
• Hospital Separations Data

ACKNOWLEDGMENTS

Dr. G.A. (Tony) Ryan provided advice on the manuscript. The Directors of the Australian spinal units provided registration information on all cases of SCI in order to assist in creating the ASCIR. The ASCIR is a data set of the AIHW and was directed by the author from its inception until 2003. DHS state-wide hospital data was provided by Julie Gardner.

Notes

∗A “match” signifies that the first and subsequent admissions had the same external cause code. The “total” refers to the total number of separations with that external cause code. The % match is the matched separations as a percentage of total separations.

Additional information

Notes on contributors

PETER J. O'CONNOR

Formerly Director of the Australian Spinal Cord Injury Register (ASCIR). Currently an epidemiologist and risk management consultant in private practice