Introduction: Traumatic brain injury (TBI) is a major health threat to United States (U.S.) military Service members. TBI is often a comorbid condition with ocular trauma (OT) due to mechanical impacts to the eyes and skull. On the battlefield, shock waves from blast explosives can cause significant TBI and ocular injuries to Service members. Studies have documented high rates of combat ocular trauma (COT) in wounded Service members with TBI. However, analogous studies are lacking to characterize concomitant ocular trauma with TBI for Service members in non-combat situations. In this study, we used real-world data (RWD) in the Military Health System (MHS) to extract critically important clinical information and examine patterns of concomitant OT with TBI – with the goal of promoting early diagnosis of TBI and optimizing patient outcomes. Methods and Materials Data: The VCE collected data from electronic health records within the Military Health System Data Repository (MDR). The MDR captures, archives, and distributes U.S. Military health care data worldwide, including more than 9 million beneficiaries. Encounter data matching the case definitions in ICD-10CM for TBI and/or ocular injury in Service members were collected from 2017 to 2021. Patients with only historic TBI diagnoses (Z87820, DOD0101, DOD0102, DOD0103, DOD0104, DOD0105) were excluded. TBI patients were classified by severity, consisting of mild, moderate, severe, and penetrating categories. OT was classified into uncomplicated and complicated categories, based on the presence of complications and surgical procedures following initial injury. TBI and OT patients were cross-referenced to identify patients with concomitant TBI and OT. Lag of TBI diagnosis in relation to the ocular injury were calculated based on the difference in days between the first dates of the relevant TBI and OT diagnoses. Concomitant OT was defined as cases with both diagnoses of TBI and OT, regardless of the lag between the two diagnoses. The case classifications and statistical analysis were conducted in R software.
Results: 71,689 Service members were diagnosed with TBI, and 69,359 OT patients were identified between 2017 to 2021. Of these patients identified, 6,605 had concomitant OT with TBI. The incidence rate of OT in TBI patients was 9.2%. Similarly, the incidence rate of TBI in OT patients was 9.5%. For concomitant OT, 31.8% patients had diagnoses of TBI and OT on the same days, and 44.7% had both diagnoses within 2 weeks. The high concurrence of diagnoses of TBI and OT suggests shared etiologies between these trauma cases. Demographically, the numbers of concomitant OT were higher in males than females. The 18-24 age group had the highest number of concomitant OT, while Service members in the Army accounted for 51.1% of concomitant cases. Proportions of severe TBI (including moderate, severe, and penetrating) were significantly higher in patients with OT than those of non-OT patients (p < 0.01). The proportion of complicated OT was significantly higher (p < 0.01) in TBI patients (39.8%) than in patients without TBI (18.8%). Incidence rates of complicated OT increased with TBI severity from 2.7% in mild TBI to 36.6% in penetrating TBI. Among various types of OT injuries, the proportions of TBI were 5%, 13%, 21%, 15% and 52% in anterior segment, lid/adnexal, closed globe, open globe, and orbital fracture patients, respectively.
Conclusions: The observed pattern of concomitant OT in TBI Service members indicates a strong association between OT and TBI. Our results provide clinically applicable information to prompt immediate screening of OT patients, especially orbital fracture patients, for early diagnosis and treatment of TBI.
Keywords: Ocular injury, MHS, Electronic Health Record
