Predicting trauma patient mortality: ICD [or ICD-10-AM] versus AIS based approaches.
BACKGROUND
The International Classification of Diseases Injury Severity Score (ICISS) has been proposed as an International Classification of Diseases (ICD)-10-based alternative to mortality prediction tools that use Abbreviated Injury Scale (AIS) data, including the Trauma and Injury Severity Score (TRISS). To date, studies have not examined the performance of ICISS using Australian trauma registry data. This study aimed to compare the performance of ICISS with other mortality prediction tools in an Australian trauma registry.


METHODS
This was a retrospective review of prospectively collected data from the Victorian State Trauma Registry. A training dataset was created for model development and a validation dataset for evaluation. The multiplicative ICISS model was compared with a worst injury ICISS approach, Victorian TRISS (V-TRISS, using local coefficients), maximum AIS severity and a multivariable model including ICD-10-AM codes as predictors. Models were investigated for discrimination (C-statistic) and calibration (Hosmer-Lemeshow statistic).


RESULTS
The multivariable approach had the highest level of discrimination (C-statistic 0.90) and calibration (H-L 7.65, P= 0.468). Worst injury ICISS, V-TRISS and maximum AIS had similar performance. The multiplicative ICISS produced the lowest level of discrimination (C-statistic 0.80) and poorest calibration (H-L 50.23, P < 0.001).


CONCLUSIONS
The performance of ICISS may be affected by the data used to develop estimates, the ICD version employed, the methods for deriving estimates and the inclusion of covariates. In this analysis, a multivariable approach using ICD-10-AM codes was the best-performing method. A multivariable ICISS approach may therefore be a useful alternative to AIS-based methods and may have comparable predictive performance to locally derived TRISS models.
Willis
Cameron D
CD
Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia. cameron.willis@adelaide.edu.au
Gabbe
Belinda J
BJ
Jolley
Damien
D
Harrison
James E
JE
Cameron
Peter A
PA
D015998:Abbreviated Injury Scale; D019540:Area Under Curve; D001315:Australia; D016001:Confidence Intervals; D016208:Databases, Factual; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D015601:Injury Severity Score; D038801:International Classification of Diseases; D008297:Male; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D012042:Registries; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D014947:Wounds and Injuries / Q000145:classification* / Q000401:mortality*