IMP-ICDX: an injury mortality prediction based on ICD-10-CM codes

Muding Wang,Yunji Zeng,Wusi Qiu,Xiao Lian,Wenhui Fan,Yi Shen

doi:10.1186/s13017-019-0265-y

Abstract

BackgroundThe International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM) Injury Severity Score (ICISS) is a risk adjustment model when injuries are recorded using ICD-9-CM coding. The trauma mortality prediction model (TMPM-ICD9) provides better calibration and discrimination compared with ICISS and injury severity score (ISS). Though TMPM-ICD9 is statistically rigorous, it is not precise enough mathematically and has the tendency to overestimate injury severity. The purpose of this study is to develop a new ICD-10-CM injury model which estimates injury severities for every injury in the ICD-10-CM lexicon by a combination of rigorous statistical probit models and mathematical properties and improves the prediction accuracy.MethodsWe developed an injury mortality prediction (IMP-ICDX) using data of 794,098 patients admitted to 738 hospitals in the National Trauma Data Bank from 2015 to 2016. Empiric measures of severity for each of the trauma ICD-10-CM codes were estimated using a weighted median death probability (WMDP) measurement and then used as the basis for IMP-ICDX. ISS (version 2005) and the single worst injury (SWI) model were re-estimated. The performance of each of these models was compared by using the area under the receiver operating characteristic (AUC), the Hosmer-Lemeshow (HL) statistic, and the Akaike information criterion statistic.ResultsIMP-ICDX exhibits significantly better discrimination (AUCIMP-ICDX, 0.893, and 95% confidence interval (CI), 0.887 to 0.898; AUCISS, 0.853, and 95% CI, 0.846 to 0.860; and AUCSWI, 0.886, and 95% CI, 0.881 to 0.892) and calibration (HLIMP-ICDX, 68, and 95% CI, 36 to 98; HLISS, 252, and 95% CI, 191 to 310; and HLSWI, 92, and 95% CI, 53 to 128) compared with ISS and SWI. All models were improved after the extension of age, gender, and injury mechanism, but the augmented IMP-ICDX still dominated ISS and SWI by every performance.ConclusionsThe IMP-ICDX has a better discrimination and calibration compared to ISS. Therefore, we believe that IMP-ICDX could be a new viable trauma research assessment method.

Highlights

Trauma score methods can be divided into two categories of systems
The injury severity score (ISS), the new injury severity score (NISS), the tangent injury severity score (TISS), the trauma mortality prediction model (TMPM), and injury mortality prediction (IMP) [1,2,3,4,5] score methods based on the Abbreviated Injury Scale (AIS) [6] lexicon
The International Classification of Diseases Ninth Edition (ICD-9-CM) Injury Severity Score (ICISS) and the trauma mortality prediction model (TMPM)-ICD9 score methods based on ICD-9-CM lexicon [8, 9]

Summary

Introduction

The injury severity score (ISS), the new injury severity score (NISS), the tangent injury severity score (TISS), the trauma mortality prediction model (TMPM), and injury mortality prediction (IMP) [1,2,3,4,5] score methods based on the Abbreviated Injury Scale (AIS) [6] lexicon. Their ability of predicting trauma death is improved [2,3,4,5, 7]. The purpose of this study is to develop a new ICD-10-CM injury model which estimates injury severities for every injury in the ICD-10-CM lexicon by a combination of rigorous statistical probit models and mathematical properties and improves the prediction accuracy

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Methods

Results

Discussion

Conclusion