Severe trauma : risks and outcomes

Trauma, “the neglected disease of modern society”, is a global health concern of enormous proportions. Knowledge about factors associated with trauma occurrence, complications and outcome is highly valuable for the improvement of trauma care. This thesis, aiming at deeper knowledge regarding trauma occurrence and outcome, used regional and national registers in four epidemiological studies with different methodologies. Prior to injury, trauma patients were treated for psychiatric disorders, substance abuse and somatic disorders to a greater extent than matched controls. Moreover, low income and low education, psychiatric disorders, substance abuse and somatic disorders were all independent risk factors for trauma after adjustment for confounders. These insights could facilitate implementation of injury prevention strategies. Severely injured patients that use β-adrenergic receptor antagonists (β-blockers) at the time of trauma had an increased mortality compared to non-users, β-blockers could thus be seen as an indicator for increased risk of death. However, after adjustment for relevant confounders no increased risk, or benefit, of β-blockers per se was noted. The protective effect of β-blockade after severe trauma suggested by previous reports could not be supported. Prospective randomized trials are needed to elucidate a role, if any, for β-blockade in the trauma setting. Acute kidney injury (AKI) affected one quarter of patients treated in the intensive care unit (ICU) following severe trauma. AKI was strongly associated with increased risk of death at 30 days and after one year. For those treated with renal replacement therapy the risk of chronic dialysis dependency after the intensive care period appears to be very low. Comorbidities such as diabetes mellitus as well as greater injury severity were strongly associated with post-injury AKI. Among preventable factors an association between resuscitation with hydroxyethyl starch (HES) and increased risk of AKI warrants caution. Administration of nephrotoxic substances should be avoided and targeted interventions may be provided to the patient at risk. Finally, trauma patients had a sustained increase in mortality several years after the index trauma. External causes, including new trauma, were far more common causes of late death in injured patients than in the background population. These findings support the concept of trauma recidivism. Two subgroups of deceased individuals could be identified; younger patients with a high prevalence of psychiatric disorders and substance abuse dying from external causes including suicide, and an older subgroup with a burden of somatic comorbidities dying from cardiovascular disorders and neoplasms. These findings emphasize the need for improved follow-up strategies and secondary prevention