The ICD-10 injury mortality diagnosis matrix

Objective: To standardize the presentation of the more than 1200 ICD-10 "S'' and "T'' codes from Chapter XIX by cross classifying the body region of injury by the nature of injury using the ICD-10 injury mortality diagnosis matrix. This paper explains the rationale for decisions made when developing the matrix and presents mortality data using the matrix. Design: ICD-10 codes are organized by diagnosis groups and body regions of injury for the purpose of standardizing presentation. The categories can be collapsed to facilitate analysis at varying levels of detail. Findings from the United States 2002 injury mortality data are used as an example. Main outcome measures: All injury diagnoses mentioned in deaths with an underlying cause of injury. Results: There were a total of 247,195 injury diagnoses mentioned in the 161,269 deaths with an underlying cause of injury in 2002 in the United States. The matrix can be used to show that 30% of all injury diagnoses mentioned were to the head and neck region; 28% were system wide injuries, 17% were to the torso. Open wounds accounted for 17% of all injury diagnoses mentioned, and close to half of all open wounds were traumatic brain injuries. Twenty eight percent of injury diagnoses mentioned were unspecified as to their nature and 9.5% had no body region specified. Conclusions: Multiple cause of death data are a rich but underused source of injury data often due to the complexity of the data and of the ICD classification system. Analytic techniques will need to be refined to accommodate deaths with multiple contributing injury diagnoses. The injury mortality diagnosis matrix will facilitate analysis as it is a useful tool for summarizing diagnosis data associated with injury deaths.