Nationwide improvements in geriatric mortality due to traumatic brain injury in Japan

Background Traumatic brain injury (TBI), both isolated and in combination with extracranial lesions, is a global health problem associated with high mortality. Among various risk factors for poor clinical outcomes, age is the most important independent predictor of mortality in patients with TBI. TBI-related mortality is expected to increase as the society ages. However, in a super-aged society such as Japan, little is known about the trend of TBI-related mortality among older adults. Herein, we assessed the nationwide trend of the incidence and clinical outcomes of geriatric patients with TBI in Japan using the national Japanese Trauma Data Bank (JTDB) registry. Methods In this retrospective cohort study, cases of TBI (aged >= 65 years) in hospitals registered with the JTDB database between January 2004 and December 2018 were included. In-hospital mortality was the primary outcome, and mortality in the emergency department was the secondary outcome. The odds ratios (ORs) and 95% confidence intervals (CIs) for in-hospital deaths with respect to 3-year periods were assessed using multivariable analysis after adjusting for potential confounders. Results The main cause of TBI in older individuals was falls. The proportion of patients who died after hospitalization during the study period decreased markedly from 29.5% (194/657) during 2004-2006 to 14.2% (1309/9240) during 2016-2018 in the isolated TBI group (adjusted OR = 0.42, 95% CI: 0.33-0.53) and from 48.0% (119/248) during 2004-2006 to 21.7% (689/3172) during 2016-2018 in the multiple trauma group (adjusted OR = 0.32, 95% CI: 0.23-0.45). The adjusted ORs for the 3-year increment were 0.84 (95% CI: 0.81-0.88) and 0.78 (95% CI: 0.75-0.83) for the isolated TBI and multiple trauma groups, respectively. Conclusions Using the national JTDB registry, we demonstrated a nationwide reduction in TBI-related mortality. Our findings in the super-aged society of Japan may provide insight for the treatment of geriatric patients with TBI worldwide.