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

INTRODUCTION: 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. METHODS: 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). RESULTS: 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%. CONCLUSIONS: 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.

The effect of transitioning to ICD-10-CM on acute injury surveillance of active duty service members.

BACKGROUND: Acute injuries are a burden on the Military Health System and degrade service members' ability to train and deploy. Long-term injuries contribute to early attrition and increase disability costs. To properly quantify acute injuries and evaluate injury prevention programs, injuries must be accurately coded and documented. This analysis describes how the transition from International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) to the Tenth Revision (ICD-10-CM) impacted acute injury surveillance among active duty (AD) service members. Twelve months of ICD-9-CM and ICD-10-CM coded ambulatory injury encounter records for Army, Navy, Air Force, and Marine Corps AD service members were analyzed to evaluate the effect of ICD-10-CM implementation on acute injury coding. Acute injuries coded with ICD-9-CM and categorized with the Barell matrix were compared to ICD-10-CM coded injuries classified by the proposed Injury Diagnosis Matrix (IDM). Both matrices categorize injuries by the nature of injury and into three levels of specificity for body region, although column and row headings are not identical. RESULTS: Acute injury distribution between the two matrices was generally similar in the broader body region categories but diverged substantially at the most granular cell level. The proportion of Level 1 Spine and back Body Region diagnoses was higher in the Barell than in the IDM (6.8% and 2.3%, respectively). Unspecified Level 3 Lower extremity injuries were markedly lower in the IDM compared to the Barell (0.1% and 12.1%, respectively). CONCLUSIONS: This is the first large scale analysis evaluating the impacts of ICD-10-CM implementation on acute injury surveillance using ambulatory encounter data. Some injury diagnoses appeared to have shifted to a different chapter of the codebook. Also, it's likely that the more detailed diagnostic descriptions and episode of care codes in ICD-10-CM discouraged re-coding of initial acute injury diagnoses. The proposed IDM did not result in a major disruption of acute injury surveillance. However, many acute injury diagnosis codes cannot be aligned between ICD versions. Overall, the increased specificity of ICD-10-CM and use of the IDM may lead to more precise acute injury surveillance and tailored prevention programs, which may result in less chronic injury, reduced morbidity, and lower health-care costs.