Long-term survival after traumatic brain injury: a population-based analysis controlled for nonhead trauma.

OBJECTIVE To examine the contribution of co-occurring nonhead injuries to hazard of death after traumatic brain injury (TBI). PARTICIPANTS A random sample of Olmsted County, Minnesota, residents with confirmed TBI from 1987 through 1999 was identified. DESIGN Each case was assigned an age- and sex-matched, non-TBI "regular control" from the population. For "special cases" with accompanying nonhead injuries, 2 matched "special controls" with nonhead injuries of similar severity were assigned. MEASURES Vital status was followed from baseline (ie, injury date for cases, comparable dates for controls) through 2008. Cases were compared first with regular controls and second with regular or special controls, depending on case type. RESULTS In total, 1257 cases were identified (including 221 special cases). For both cases versus regular controls and cases versus regular or special controls, the hazard ratio was increased from baseline to 6 months (10.82 [2.86-40.89] and 7.13 [3.10-16.39], respectively) and from baseline through study end (2.92 [1.74-4.91] and 1.48 [1.09-2.02], respectively). Among 6-month survivors, the hazard ratio was increased for cases versus regular controls (1.43 [1.06-2.15]) but not for cases versus regular or special controls (1.05 [0.80-1.38]). CONCLUSIONS Among 6-month survivors, accounting for nonhead injuries resulted in a nonsignificant effect of TBI on long-term mortality.