Development and validation of a new ICD-10-based trauma mortality prediction scoring system using a Japanese national inpatient database.
To develop and validate a new trauma mortality prediction scoring system based on International Statistical Classification of Diseases (ICD)-10 codes, using a Japanese administrative claims and discharge abstract database.



This retrospective observational study used the Japanese Diagnosis Procedure Combination database. Injuries were categorised into 33 groups with 5 additional groups based on injury sites and types. A multivariable logistic regression analysis was performed for in-hospital mortality in a derivation cohort after adjusting for the 38 groups, patient's sex, age and Charlson Comorbidity Index score. Each variable was assigned a score that was equal to the value of the regression coefficient. The new severity score was defined as the sum of the scores. The new scoring system was tested in a validation cohort.



The mortality rates were 2.4% (9270/393 395) and 2.5% (8778/349 285) in the derivation and validation cohorts, respectively. The area under the receiver operating curve (AUROC) of the new scoring system was 0.887 (95% CI 0.884 to 0.890) in the validation cohort. Subgroup analyses showed that the scoring system retained high predictive performance both for patients <65 years (AUROC 0.934, 95% CI 0.928 to 0.939) and for elderly patients at the age of ≥65 years (AUROC 0.825, 95% CI 0.820 to 0.829).



A new ICD-10-based injury severity scoring system was developed and validated. Further studies are required to validate the scoring system in other databases.
Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Tokyo, Japan.
Tomoki
T
Wada
Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan.
Hideo
H
Yasunaga
Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan.
Hayato
H
Yamana
Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan.
Hiroki
H
Matsui
Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Tokyo, Japan.
Takehiro
T
Matsubara
Department of Health Policy and Informatics, Tokyo Medical and Dental University, Tokyo, Japan.
Kiyohide
K
Fushimi
Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Tokyo, Japan.
Susumu
S
Nakajima
D000328:Adult; D000368:Aged; D015897:Comorbidity; D016208:Databases, Factual; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D015601:Injury Severity Score; D007297:Inpatients / Q000706:statistics & numerical data*; D038801:International Classification of Diseases / Q000639:trends; D007564:Japan; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D020379:Risk Adjustment; D014947:Wounds and Injuries / Q000145:classification* / Q000401:mortality