Early Factors Related to Healthcare Utilization by Infection Status among Combat Injured

Abstract

Introduction: Combat casualty care is resource-intensive; however, the impact of battlefield-related infections on healthcare utilization is not fully understood. We assessed factors associated with hospitalization among wounded military personnel by infection outcome.

Materials and methods: The study population for this cross-sectional retrospective analysis included military personnel wounded during deployment (June 1, 2009-December 31, 2014), admitted to Landstuhl Regional Medical Center (Germany), and transferred to participating military hospitals in the continental United States. Patients consented to the review of electronic medical records through the Military Health System (MHS) Data Repository. Patients were classified as having a trauma-related infection with a multidrug-resistant Gram-negative bacillus, infection attributed to other pathogens, or without infection during initial hospitalization. Hospital healthcare utilization within the first 2 weeks post-injury among patients with infections was assessed to identify factors associated with longer hospitalization.

Results: The study population consisted of 1,018 patients; 148 patients with a multidrug-resistant Gram-negative bacilli infection, 320 with an infection attributed to another pathogen, and 550 without infections. Hospital length of stay was a median of 59.5 days for patients with multidrug-resistant Gram-negative bacilli infections compared to 42 days for infections with other pathogens and 22 days for patients without infections (P < .001). Critical care (e.g., intensive care unit admission/duration, mechanical ventilation, and procedures), and collection of clinical cultures were more frequent among patients with multidrug-resistant Gram-negative bacilli infections compared with those with other pathogens and without infections (P < .05) and are plausible factors to potentially explain why their longer hospitalization. Patients with multidrug-resistant Gram-negative bacilli infections received more aminoglycosides, aminopenicillin, antipseudomonal penicillin, antiparasitics, antifungals, carbapenems, macrolides, polymyxins, trimethoprim-sulfamethoxazole, and vancomycin than patients with infections attributed to other pathogens (P < .05), with an overall greater duration of antimicrobial use (median: 51 vs. 38 days; P < .001). When adjusted for injury severity, clinical microbiology workups, surgeries, and other factors shown to be associated with hospitalization in the multivariate model, having an infection with a multidrug-resistant Gram--negative bacillus was associated with a stay of 5 extra days for every 30 days stayed by a patient with infections attributed to other pathogens.

Conclusions: Combat casualty care is associated with high resource utilization and the occurrence of multidrug-resistant Gram-negative bacilli infections significantly adds to the healthcare burden on the MHS. Examination of incremental changes in healthcare costs associated with battlefield-related infections is warranted to inform the allocation of needed resources to treat these patients.