What Does the Military Health System Need to Support Future Combat Operations? Lessons from Aeromedical Evacuations from 2008 to 2020

Aeromedical evacuations from the past few decades have yielded massive amounts of data that may inform the Military Health System (MHS) on patient needs, specifically for understanding the inpatient and outpatient needs of evacuees. In this study, we evaluate inpatient and outpatient trends based on aeromedical evacuation data from recent conflicts. We anticipate that evacuations requiring MHS inpatient beds are primarily trauma-related and necessitate an increased need for inpatient trauma care.We conducted a descriptive analysis of aeromedical evacuations using the U.S. Transportation Command Regulating and Command & Control Evacuation System database. We queried the database for aeromedical evacuations originating from the U.S. EUCOM and ending in the CONUS, from January 1, 2008 to June 4, 2020. With the resultant data, evacuee demographics were characterized by gender, age, active duty (AD) versus non-AD, and branch of service. Following this, the proportion of battle injury to disease and non-battle injury was categorized by both patient age ranges and year. Additionally, evacuations were stratified by their ICD codes, as well as the primary specialty responsible for care. Lastly, evacuations were categorized by inpatient and outpatient care status.The final dataset yielded 32,485 unique patients. The majority of evacuees were male (86.9%) with a mean age of 29.0 ± 9.6 years. Evacuees were primarily AD Military (96.7%), with the majority of those personnel being in the Army (70.2%). The total number of evacuations steadily increased from 2008 (n = 3,703) until a peak in 2010 (n = 4,929), which was also the peak year for battle injury (n = 1,472). Battle injury was also most prevalent in the 21 to 24 age group (24.7%) and declined in older age groups. Regarding diagnoses, the leading categories were injury/poisoning (33.1%), psychiatric (28.1%), and musculoskeletal (12.1%). As for specialty care of evacuees, psychiatry received the largest share of total evacuations (28.1%), followed by orthopedic surgery (22.7%) and general surgery (8.6%). Looking at proportions of inpatient and outpatient care, the majority of evacuees required outpatient care (65.6%) with a sizable minority requiring inpatient care (34.4%). Inpatient evacuations peaked in 2010 (n = 2,013), accounting for 40.8% of all evacuations that year. Orthopedic surgery had the largest share of inpatient evacuations (27.3%), followed by psychiatry (21.5%) and general surgery (18.2%). As for outpatient care, the specialties with the largest proportion of outpatient evacuations were psychiatry (33.6%), orthopedic surgery (20.3%), and neurology (9.8%).The results of this study reveal what the MHS can expect in future conflicts. Most evacuations are for psychiatric-/injury-/musculoskeletal-related diagnoses, typically requiring care by psychiatrists, orthopedic surgeons, or general surgeons. Outpatient care is important, though it is critical to bolster inpatient care requirements as future conflicts may bring extensive numbers of inpatient casualties. The MHS should program and plan resources accordingly, planning for the care of surgical/injured and psychiatric patients.