Diagnoses and factors associated with medical evacuation and return to duty for service members participating in Operation Iraqi Freedom or Operation Enduring Freedom: a prospective cohort study

Abstract

Anticipation of the types of injuries that occur in modern warfare is essential to plan operations and maintain a healthy military. We aimed to identify the diagnoses that result in most medical evacuations, and ascertain which demographic and clinical variables were associated with return to duty. Demographic and clinical data were prospectively obtained for US military personnel who had been medically evacuated from Operation Iraqi Freedom or Operation Enduring Freedom (January, 2004-December, 2007). Diagnoses were categorised post hoc according to the International Classification of Diseases codes that were recorded at the time of transfer. The primary outcome measure was return to duty within 2 weeks. 34 006 personnel were medically evacuated, of whom 89% were men, 91% were enlisted, 82% were in the army, and 86% sustained an injury in Iraq. The most common reasons for medical evacuation were: musculoskeletal and connective tissue disorders (n=8104 service members, 24%), combat injuries (n=4713, 14%), neurological disorders (n=3502, 10%), psychiatric diagnoses (n=3108, 9%), and spinal pain (n=2445, 7%). The factors most strongly associated with return to duty were being a senior officer (adjusted OR 2.01, 95% CI 1.71-2.35, p<0.0001), having a non-battle-related injury or disease (3.18, 2.77-3.67, p<0.0001), and presenting with chest or abdominal pain (2.48, 1.61-3.81, p<0.0001), a gastrointestinal disorder (non-surgical 2.32, 1.51-3.56, p=0.0001; surgical 2.62, 1.69-4.06, p<0.0001), or a genitourinary disorder (2.19, 1.43-3.36, p=0.0003). Covariates associated with a decreased probability of return to duty were serving in the navy or coast guard (0.59, 0.45-0.78, p=0.0002), or marines (0.86, 0.77-0.96, p=0.0083); and presenting with a combat injury (0.27, 0.17-0.44, p<0.0001), a psychiatric disorder (0.28, 0.18-0.43, p<0.0001), musculoskeletal or connective tissue disorder (0.46, 0.30-0.71, p=0.0004), spinal pain (0.41, 0.26-0.63, p=0.0001), or other wound (0.54, 0.34-0.84, p=0.0069). Implementation of preventive measures for service members who are at highest risk of evacuation, forward-deployed treatment, and therapeutic interventions could reduce the effect of non-battle-related injuries and disease on military readiness. John P Murtha Neuroscience and Pain Institute, and US Army Regional Anesthesia and Pain Management Initiative.