Validation of the "HAMP" mapping algorithm: a tool for long-term trauma research studies in the conversion of AIS 2005 to AIS 98.
BACKGROUND
There are significant changes in the abbreviated injury scale (AIS) 2005 system, which make it impractical to compare patients coded in AIS version 98 with patients coded in AIS version 2005.


METHODS
Harborview Medical Center created a computer algorithm "Harborview AIS Mapping Program (HAMP)" to automatically convert AIS 2005 to AIS 98 injury codes. The mapping was validated using 6 months of double-coded patient injury records from a Level I Trauma Center. HAMP was used to determine how closely individual AIS and injury severity scores (ISS) were converted from AIS 2005 to AIS 98 versions. The kappa statistic was used to measure the agreement between manually determined codes and HAMP-derived codes.


RESULTS
Seven hundred forty-nine patient records were used for validation. For the conversion of AIS codes, the measure of agreement between HAMP and manually determined codes was [kappa] = 0.84 (95% confidence interval, 0.82-0.86). The algorithm errors were smaller in magnitude than the manually determined coding errors. For the conversion of ISS, the agreement between HAMP versus manually determined ISS was [kappa] = 0.81 (95% confidence interval, 0.78-0.84).


CONCLUSIONS
The HAMP algorithm successfully converted injuries coded in AIS 2005 to AIS 98. This algorithm will be useful when comparing trauma patient clinical data across populations coded in different versions, especially for longitudinal studies.
Quality Improvement Department, Harborview Medical Center, Seattle, WA, USA. derka@uw.edu
Derk
D
Adams
Astrid B
AB
Schreuder
Kristin
K
Salottolo
April
A
Settell
J Richard
JR
Goss
D015998:Abbreviated Injury Scale; D000465:Algorithms; D035843:Biomedical Research / Q000458:organization & administration*; D006801:Humans; D008499:Medical Records / Q000706:statistics & numerical data*; D014193:Trauma Centers / Q000706:statistics & numerical data*; D014481:United States; D014947:Wounds and Injuries / Q000145:classification*