Age-associated increases in poor outcomes after traumatic brain injury: a report from the Japan Neurotrauma Data Bank.

Age is an important factor influencing outcome after severe traumatic brain injury (TBI). In general, the older the victim, the higher the probability of a poor outcome. To investigate the mechanism underlying the link between age and outcome, the data for 797 patients enrolled in the Japan Neurotrauma Data Bank (JNTDB), aged 6 years or older, with Glasgow Coma Scale (GCS) scores of 8 or less on admission or deterioration to that level within 48 h of impact were analyzed. Thirty-eight percent of the patients were between the ages of 40 and 69 years, and 24% of the patients were older than 69 years. Older patients had higher rates of mortality and lower rates of favorable outcome. The frequency of mass lesions which were associated with poorer outcomes significantly increased with age, but regardless of the intracranial lesion type, older patients had poorer outcomes. The GCS score and the occurrence of systemic complications did not differ significantly according to age. Multiple systemic injury was less frequent in older patients. The varied occurrence of intracranial lesion types according to age is likely caused by the disparity between the young and aged brain in the progression of secondary brain injury. Alteration in the pathophysiological response, which is related to the development of secondary brain injury in the aging brain, probably contributes to more severe and irreversible brain damage in older patients, and is thus associated with poor outcomes.