Women’s Health
Sex differences in posttraumatic pain development after acute physical trauma Rachel Gaither* Rachel Gaither Nina Joyce Sarah Linnstaedt Samuel McLean Francesca Beaudoin
Chronic pain impacts >50 million US adults, with women about twice as likely to report chronic pain as men. Acute physical trauma (e.g. motor vehicle crash) is a common catalyst for chronic pain, and its defined time origin is useful for investigating pain development. Few analyses have investigated sex differences in posttraumatic pain despite evidence that adverse symptoms are more common in female trauma survivors. We used the AURORA cohort (n=3789) to assess whether female sex assigned at birth is associated with increased likelihood of chronic pain development after trauma exposure. Participants were enrolled in the emergency department (ED) after presenting with non-life-threatening physical trauma and followed serially for one year. Sex was defined as sex assigned at birth, and pain was assessed in the ED and at 2-weeks, 2-, 3-, 6-, and 12-months post-trauma using the 0-10 Numeric Rating Scale (score ≥4 indicating moderate/severe pain). Log-binomial regression models with inverse probability of censoring weights were used at each timepoint to determine the association between sex and pain severity while accounting for potential selection bias due to differential loss to follow-up by sex. Baseline characteristics were similar across sex and posttraumatic pain was common overall, with 77.8% and 55.7% of participants reporting moderate/severe pain at 2 weeks and 3 months, respectively. Prevalence of pain pre-trauma and in the ED was similar across sex, but individuals assigned female at birth had increased risk of moderate/severe pain compared to those assigned male by 2 weeks (RR [95% CI]: 1.20 [1.16-1.25]). This elevated risk persisted throughout follow-up (3-month: 1.28 [1.20-1.37], 6-month: 1.32 [1.22-1.41]). Overall, female sex at birth was associated with higher risk of posttraumatic chronic pain, and subsequent work should investigate the impact of sex on pain recovery trajectories over time while incorporating specific measures of sex characteristics.