The Impacts of ICD-10-CM on U.S. Army Injury Surveillance

Abstract

Injuries are the leading cause of medical encounters and lost work days in the U.S. Army, affecting more than half of active-duty soldiers annually. Historically, Army injury surveillance has captured both acute traumatic and cumulative microtraumatic overuse injuries. This article describes how the transition from the ICD-9-CM to ICD-10-CM impacted U.S. military injury surveillance by comparing injury rates and distributions under both systems. Mapping ICD-9-CM codes to the expanded ICD-10-CM codes is not a straightforward endeavor; therefore, the Army Public Health Center incorporated ICD-10-CM codes into a comprehensive, systematic approach to taxonomically categorize injuries. This taxonomic methodology was applied to Army injuries under ICD-10-CM (2016-2019) and compared with the ICD-9-CM Army injury surveillance definitions (2012-2015). Soldier injury rates appeared to increase when surveillance with ICD-10-CM began. Soldiers experienced 1,276 incident injury medical encounters per 1,000 person-years in 2015 (ICD-9-CM), compared with 1,804 injuries per 1,000 in 2016 (ICD-10-CM), a 41% increase. Importantly, the distribution of injuries also shifted, such that the average cumulative microtraumatic injury rate increased by 42% during 2016-2019 (ICD-10-CM) compared with the 2012-2015 average (ICD-9-CM), whereas acute traumatic injuries only increased by 17%. The enhanced descriptions provided by ICD-10-CM codes and the applied taxonomic categorizations have improved precision in Army injury surveillance. Data unequivocally show that most injuries in this physically active population are cumulative microtraumatic injuries. The taxonomic methodology can be extended to injury surveillance in other populations and may allow a more efficient transition to ICD-11-CM.