Long-Term Impact of Trauma in Twins

Abstract

Trauma remains a leading cause of death and disability worldwide. For those who survive a severe traumatic injury, the personal costs are subjectively substantial but may be difficult to objectively quantify. Previous studies attempting to do this have determined that many factors are associated with long-term outcomes, including injury severity, 1 age, 2 sex, 3 presence of traumatic brain injury, 4 insurance status, 5 and household size. 2 Additional studies have attempted to evaluate the longterm impact of trauma on physiological processes. Investigators have demonstrated alterations in the inflammatory and immune responses after trauma, 6-8 but these studies have focused on relatively short-term time points. Although the longterm effects of traumatic injury on inflammatory and immune responses remain incompletely understood, studies in burn patients indicate that the effects of thermal injury on metabolism and inflammatory pathways likely persist for years, if not permanently. 9 The study by Eskesen et al 10 adds significantly to our understanding of the real long-term cost of traumatic injury. The investigators sought to address the question of whether moderate to severe trauma is associated with increased risk of late death, immune-mediated disease, or cancer. To investigate this, they used the Danish Twins Registry and the Danish National Patient Registry to identify twin pairs where 1 twin experienced a moderate or severe traumatic injury (defined as an Injury Severity Score ≥9) and the other did not. Their analysis included 2290 pairs of twins with a median follow-up time of 8.6 years.The results of this study are striking. The hazard ratio for the twin who was exposed to trauma reaching the composite out-