External Cause Coding of Injury Encounters in the Military Health System Among Active Component U.S. Service Members, 2016–2019

Knowledge of injury causes is essential for prevention. To investigate cause coding in service members’ electronic medical records, injury encounters from 2016 to 2019 containing at least 1 external cause code were analyzed. Approximately 10% of incident injury encounters contained at least 1 cause code describing the mechanism, activity, or place of occurrence. Less than 2% of overuse injury encounters had a cause code each year, compared to 36.4– 44.0% of acute injuries occurring from 2016 to 2019. Cause coding occurred more frequently in records from military facilities compared to outsourced care (p < 0.001). Inpatient records were more likely to be cause-coded than outpatient records (p < 0.001). More injury encounters in emergency clinics were cause coded (> 50%), compared to approximately 7% of primary care and 2% of specialist encounters. In 2019, the leading mechanism was overex-ertion (19.9%), followed by falls, slips, or trips (18.7%). The primary activity associated with injuries was running (21.1%). Military training ground was the leading place of occurrence (13.0%). Improvements to the quality and quantity of external cause coding in the medical records would provide criti-cal details to inform military injury prevention.