Venous thromboembolism among United States soldiers deployed to Southwest Asia

Introduction: Military operations may represent a high-risk environment for venous thromboembolism (VTE). We sought to identify and describe cases of venous thromboembolism among US military personnel serving in Southwest Asia, and estimate relative disease rates compared to non-deployed personnel. Materials and methods: Retrospective review of imaging archives, hospital discharge codes, case logs and autopsy records for the diagnosis of deep vein thrombosis or pulmonary embolism occurring from 1 March 2003 through 29 February 2004 among U.S. military personnel deployed to Southwest Asia. Rates of disease in deployed and non-deployed active-duty soldiers were estimated using personnel data and deployment experience obtained from automated rosters. Results: Forty cases of venous thromboembolism were identified. The case-fatality rate was 16% (3 / 19) among those with pulmonary embolism. Antecedent trauma followed by prolonged air evacuation was present in 55% (22 / 40). Compared to trauma-associated cases, non-trauma cases were more commonly over 40 years old (44% vs. 5%; p < 0.05), assigned to a transportation or quartermaster company (56% vs. 14%; p < 0.05), or had a history of remote venous thromboembolism (31% vs. 0%; p < 0.05). The overall incidence among deployed active-duty soldiers was 22.1 / 100,000 person-years. Compared to non-deployed active-duty soldiers, the age-adjusted incidence rate ratio was 1.06 (CI_0.95 0.68-1.67). Conclusions: VTE rates among deployed soldiers are relatively low compared to the general population, and are comparable to non-deployed soldiers. Fatalities from PE are not uncommon, and vigilance among clinicians remains warranted. Trauma followed by prolonged air evacuation or ground transport during military operations may represent unique interactive risk factors for venous thromboembolism.