The elderly age criterion for increased in-hospital mortality in trauma patients: a retrospective cohort study

Background With an aging population, the number of elderly individuals exposed to traumatic injuries is increasing. The elderly age criterion for traumatic injuries has been inconsistent in the literature. This study aimed at specifying the elderly age criterion when the traumatic mortality rate increases. Methods This is a multicenter retrospective cohort study that was conducted utilizing the data from the Emergency Department-based Injury In-depth Surveillance Registry of the Korea Disease Control and Prevention Agency, collected between January 2014 and December 2018 from 23 emergency departments. The outcome variable was in-hospital mortality. Multivariable logistic regression analysis was used to calculate the adjusted mortality rate for each age group. By using the shape-restricted regression splines method, the relationship between age and adjusted traumatic mortality was plotted and the point where the gradient of the graph had the greatest variation was calculated. Results A total of 637,491 adult trauma patients were included. The number of in-hospital deaths was 6504 (1.0%). The age at which mortality increased the most was 65.06 years old. The adjusted odds ratio for the in-hospital mortality rate with age in the <= 64-year-old subgroup was 1.038 (95% confidence interval (CI) 1.032-1.044) and in the >= 65-year-old subgroup was 1.059 (95% CI 1.050-1.068). The adjusted odds ratio for in-hospital mortality in the >= 65-year-old compared to the <= 64-year-old subgroup was 4.585 (95% CI 4.158-5.055, p < 0.001). Conclusions This study found that the in-hospital mortality rate rose with increasing age and that the increase was the most rapid from the age of 65 years. We propose to define the elderly age criterion for traumatic injuries as >= 65 years of age.