Accuracy of external cause-of-injury coding in VA polytrauma patient discharge records

Valid and efficient methods of identifying the etiology of treated injuries are critical for characterizing patient populations and developing prevention and rehabilitation strategies. We examined the accuracy of external cause-of-injury codes (E-codes) in Veterans Health Administration (VHA) administrative data for a population of injured patients. Chart notes and E-codes were extracted for 566 patients treated at any one of four VHA Polytrauma Rehabilitation Center sites between 2001 and 2006. Two expert coders, blinded to VHA E-codes, used chart notes to assign "gold standard" E-codes to injured patients. The accuracy of VHA E-coding was examined based on these gold standard E-codes. Only 382 of 517 (74%) injured patients were assigned E-codes in VHA records. Sensitivity of VHA E-codes varied significantly by site (range: 59%-91%, p < 0.001). Sensitivity was highest for combat-related injuries (81%) and lowest for fall-related injuries (60%). Overall specificity of E-codes was high (92%). E-coding accuracy was markedly higher when we restricted analyses to records that had been assigned VHA E-codes. E-codes may not be valid for ascertaining source-of-injury data for all injuries among VHA rehabilitation inpatients at this time. Enhanced training and policies may ensure more widespread, standardized use and accuracy of E-codes for injured veterans treated in the VHA.