Aeromedical Evacuations from Operation Iraqi Freedom: A Descriptive Study

Military Medicine, Jun 2005 by Harman, Dale R, Hooper, Tomoko I, Gackstetter, Gary D

Figure 3 depicts the distribution of DNBI and combat injury by month. Battle injuries peaked in April (n = 419) and DNBI peaked in July (n = 1,506). Figure 4 represents the proportion of battle injuries versus DNBI across age categories. As age increased, the proportion of battle injuries declined.

For purposes of future epidemiological analyses using linked TRAC^sup 2^ES and DMSS data, we determined that pre- and postdeployment questionnaire information was available for about two-thirds of the patients (61.6% and 65.2%, respectively). Additionally, 86.2% of evacuees had one or more outpatient encounters and 33% were hospitalized at least once for any cause before or following their deployment to OIF.

Table III provides the age distribution of aeromedical evacuees by gender and service branch. The "typical" patient is a young adult male in the Army. Data on gender for 411 patients (3.7%) and age for 330 patients (2.9%) were missing.

Of the 59 MEDSPEC codes included in the TRAC^sup 2^ES data, the 10 most common are listed in Table IV. Orthopedic (21.5%) and general surgery (13.3%) patients were the most common. The next most common MEDSPEC code was psychiatry, which accounted for nearly 7% of all cases.

Table V lists the primary ICD-9-CM codes assigned to evacuated patients within each of the 17 major diagnostic categories. Injuries and musculoskeletal conditions were the two largest categories, and, when combined, they constituted 40.8% of all cases. Diseases of the digestive system (9.1%) followed by symptoms, signs, and ill-defined conditions (8.3%) were the next largest groups. Nervous system disorders (6.4%), mental disorders (6.1%), and disorders of the genitourinary system (6.1%) comprised the remaining major categories. All other categories each made up less than 3% of the total number of patients.

Discussion

We have provided a broad overview of all military patients who were aeromedically evacuated from the OIF theater in the calendar year 2003. Not only do we gain useful information about the medical operations in OIF, but we also acquire insight into the potential utility of a transportation database as an epidemiological tool.

ICD-9-CM codes and MEDSPEC categories together provide useful information on resource needs. As expected, MEDSPEC codes indicated that orthopedic and general surgery capabilities were in high demand. However, psychiatric care was also a major requirement for patients evacuated from theater. Not surprisingly, injuries and musculoskeletal conditions were by far the most common ICD-9-CM diagnostic categories for evacuated patients. Less common, but each constituting between 5 and 10% of diagnostic categories were diseases of the digestive system; signs, symptoms, and ill-defined conditions; nervous system disorders; mental disorders; and disorders of the genitourinary system. These medical events warrant further investigation into their nature and circumstances.

Given the young Army male's predominant role in OIF, it follows that this group comprised the vast majority of aeromedically evacuated patients. Reliable denominator data would allow us to calculate rates and conduct subgroup analyses but are difficult to obtain because of constant troop movement, the high operational tempo, and the combat environment, as well as for security reasons. Reliable information on unusual patterns of illness or injury rates within the service branches and trends by age, gender, and occupation would assist medical planners and decision makers.