Preinjury Health Status of Adults With Traumatic Brain Injury: A Preliminary Matched Case-Control Study.

The study was small and preliminary: 62 adults with TBI were matched to 171 controls, and the authors say this gave low power and a higher chance of missing true differences. It included only adults over 40 who received inpatient rehabilitation for complicated mild, moderate, or severe TBI, so it may not apply to people with mild TBI or those who did not need inpatient rehab. Controls came from a different survey and were not recruited after a head injury event. Matching was only on age, sex, race, education, and employment, so other differences may explain the findings. Prior-year health was recalled after injury. For TBI cases, 35.5% of responses were provided by a proxy informant and 9.7% used a mix of proxy and self-report, which may differ in accuracy from self-report. Some controls could still have had an unreported TBI because only self-reported serious head injury was excluded. The authors say this misclassification would likely push results toward the null. Age was not fully balanced after matching: the standardized difference was 0.18 for mean age and 0.16 for median age, while differences above 10% were flagged for further adjustment.

The authors declared no conflicts of interest.

Do not read the four times higher odds of prior-year depressive symptoms as proof that depression causes TBI or that treating depression prevents TBI. This was a small, preliminary case-control study of 62 adults with TBI and 171 controls, and most other prior-year health and behavior measures did not differ.