['It is now well accepted that traumatic white matter injury constitutes a critical determinant of post-traumatic functional impairment. However, the contribution of preexisting white matter rarefaction on outcome following traumatic brain injury (TBI) is unknown. Hence, we sought to determine whether the burden of preexisting leukoaraiosis of presumed ischemic origin is independently associated with outcome after TBI.', 'We retrospectively analyzed consecutive, prospectively enrolled patients of ≥50\xa0years (n\xa0=\xa0136) who were admitted to a single neurological/trauma intensive care unit. Supratentorial white matter hypoattenuation on head CT was graded on a 5-point scale (range 0-4) reflecting increasing severity of leukoaraiosis. Outcome was ascertained according to the modified Rankin Scale (mRS) and Glasgow outcome scale (GOS) at 3 and 12\xa0months, respectively.', 'After adjustment for other factors, leukoaraiosis severity was significantly associated with a poor outcome at 3 and 12\xa0months defined as mRS 3-6 and GOS 1-3, respectively. The independent association between leukoaraiosis and poor outcome remained when the analysis was restricted to patients who survived up to 3\xa0months, had moderate-to-severe TBI [enrollment Glasgow Coma Scale (GCS) ≤12; p\xa0=\xa00.001], or had mild TBI (GCS 13-15; p\xa0=\xa00.002), respectively.'] Does severe leukoaraiosis portend a poor outcome after traumatic brain injury?