Differential Pain Presentations Observed across Post-Traumatic Stress Disorder Symptom Trajectories after Combat Injury

Abstract

Abstract Objective This study evaluated the association between pain outcomes and post-traumatic stress disorder (PTSD) symptom trajectories after combat-related injury, while adjusting for receipt of regional anesthesia (RA) soon after injury. Methods The PTSD symptom trajectories of N = 288 combat-injured service members were examined from within a month of injury up to two-years after. Linear mixed-effects models evaluated the association between PTSD symptom trajectories and average pain and pain interference outcomes while adjusting for receipt of RA during combat casualty care. Results Four PTSD trajectories were characterized: resilient, recovering, worsening, and chronic. Differential pain presentations were associated with PTSD symptom trajectories, even after adjusting for receipt of RA. Compared to those with a resilient PTSD symptom trajectory, individuals presenting with chronic PTSD trajectories were estimated to experience average pain scores 2.61 points higher (95% CI: 1.71, 3.14). Participants presenting with worsening (β = 1.42; 95% CI: 0.77, 1.78) and recovering PTSD trajectories (β = 0.65; 95% CI: 0.09, 1.08) were estimated to experience higher average pain scores than participants with resilient PTSD trajectories. Significant differences in pain interference scores were observed across PTSD trajectories. Receiving RA was associated with improved pain up to two years after injury (β = -0.31; 95% CI: -0.90, -0.04), however no statistically significant association was detected between RA and PTSD trajectories. Conclusions Chronic and worsening PTSD trajectories were associated with greater pain intensity and interference following combat injury even when accounting for receipt of early RA for pain management. These findings underscore the need to jointly assess pain and PTSD symptoms across the trauma care continuum.