To examine the contribution of cooccurring nonhead injuries to hazard of death after traumatic brain injury (TBI).
A random sample of Olmsted County, Minnesota, residents with confirmed TBI from 1987 through 1999 was identified.
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.
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.
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]).
Among 6-month survivors, accounting for nonhead injuries resulted in a nonsignificant effect of TBI on long-term mortality.
Department of Physical Medicine and Rehabilitation (Dr Brown), Division of Epidemiology (Dr Leibson), Division of Biomedical Statistics and Informatics (Dr Mandrekar and Ms Ransom), Department of Neurology (Dr Mandrekar), and Department of Psychiatry and Psychology (Dr Malec), Mayo Clinic, Rochester, Minnesota; and Department of Physical Medicine and Rehabilitation, Indiana University School of Medicine and Rehabilitation Hospital of Indiana, Indianapolis (Dr Malec).
Corresponding Author: Allen W. Brown, MD, Department of Physical Medicine and Rehabilitation, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (firstname.lastname@example.org).
Portions of the Methods section have been published previously in Leibson CL, Brown AW, Hall Long K, et al. Medical care costs associated with traumatic brain injury over the full spectrum of disease: a controlled population-based study. J Neurotrauma. 2012;29(11):2038–2049. Used with permission.
The authors thank Turner M. Osler, MD, for assistance in using the Trauma Mortality Prediction Model. They also thank Patricia K. Perkins, Margaret Donohue, and Nancy N. Diehl for invaluable and expert assistance in medical-record abstraction, data collection, and analysis.
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This work was supported by TBI Model System grants to Mayo Clinic from the National Institute on Disability and Rehabilitation Research (H133A020507, H133A070013) and a National Research Service Award from the National Institute of Health (Training Grant HD-07447). The study was made possible by the Rochester Epidemiology Project (grant no. R01 AG034676 from the National Institute on Aging).
The authors declare no conflicts of interest.