Abbreviated Injury Scale Measures of severity ICE on injury statistics Maria Segui-Gomez

Agenda Brief history Uses and overuses Advantages/limitations over other severity measures –common criticisms

Disclaimer I was a member of the AAAM Injury Scaling Committe from and now I am back on it

The AIS is An anatomically based, consensus derived, global severity scoring system that classifies each injury in every body region according to its relative importance on a six point ordinal scale T. Genarelli, AAAM annual meeting 2003

Purposes of AIS Describe injuries anatomically Standardize injury terminology Rank injuries by severity Facilitate comparisons of injury studies

History 1971 AAAM and SAE get together to develop a tool that will allow injury and injury severity characterization for physicians and motor vehicle engineers Injury severity defined as a mix of death threat, energy dissipation, disability, duration of treatment and incidence of injury In 1974, first release with approximately 70 injuries given severity scores ranging 1-6

Several revisions leading up to AIS 1985 were current format was adopted

AIS 1990 (with 1998 update) well extended AIS 2005 just released. –Expansion in format –Incorporation of Orthopedic Trauma Association codes for fractures –6.1 (2+2) 2000 codes (and them some) –Allows for specification of aspect and others

Over time things have… …remained constant: Pre dot injury descriptor Post dot severity descriptor Severity range 0-6 Expert assessment of severity..or changed: Definition of severity – narrowed to threat to life Expanded to non motor vehicle injuries (e.g., burns) Expanded to pediatric injuries Expanded to include LOC for brain injury –only exception to anatomic basis

Overall Produced centrally by AAAM Used in all in-depth crash investigation efforts in US and Europe (NASS CDS, CIREN, CCIS, German database) and in many more in other continents Bases for motor vehicle regulation in US, Canada, Australia, Japan and Europe Used in some 1600 papers since 1975 avaliable throug Pub Med and many more engineering papers not available trhough Pub Med Available in English, Spanish, Chinese, French, German, Italian Certification for coding in place in US –plans to extend abroad

Some big helpers Mapping from ICD-9-CM to AIS85 introduced AIS to massive health-related databases such as hospital discharge data –Updated to AIS1990 (update 1998) Other “maps” available in several Trauma Registry software packages Its body region classification has been widely adopted (maybe until arrival of Barell matrix)

Common Criticisms Expert assement (as in subjective, poor) Same severity score does not mean the same in different body regions Presumes otherwise healthy individual, up to standard health care, single injuries You have to buy a license There is no map for ICD-10

But Not all injuries are sufficiently frequent in real world databases On actual comparison of AIS and death at hospital discharge (as printed in AIS 2005 manual): Data from NTR -ACS

And… Same severity score does not mean the same in different body regions ?¿?¿ Presumes otherwise healthy individual, up to standard health care, single injuries You have to buy a license. Yes, 190$ each There is no map for ICD-10. No, we just finished one to AIS-98! Plans to map to AIS05 underway

Head to Head comparison AIS Expert assement –Broader definition of time to death Single injury, can combine Universal ICISS Empirically based –If hospital, death to discharge, if death certificate… Each injury goes in with whichever proportion of other injuries are present (and reported) Which version? Which country? Which datasource? Which year? Both are anatomically based, assign severity to some 2000 descriptors, ignore many other confounders (for death)

In sum No perfect measure Not perfect for all and every use But at least common language across disciplines and countries