Anxiety and Posttraumatic Stress Disorder Among Medicare Beneficiaries After Traumatic Brain Injury.

The study used Medicare billing codes, not clinical assessments, so anxiety and PTSD may be undercounted or miscoded. No information was available about how diagnoses were made, TBI severity, or psychiatric illness severity. The pre-TBI period averaged 28 months, not lifetime, so some 'new' diagnoses may have existed before the study period. The sample included only Medicare beneficiaries aged 65 and older who survived hospitalization and were hospitalized with TBI, so it does not apply to younger adults or most mild TBIs that do not cause hospitalization. PTSD was very rare, with 218 diagnoses before TBI and 269 after TBI, and the confidence intervals were wide. Because this was an observational claims study, it cannot show that TBI caused anxiety or PTSD; prior psychiatric conditions and other factors may explain part of the association. Some earlier TBI hospitalizations may have occurred before the study period, which would bias results toward the null.

The supplied text does not include a conflict-of-interest declaration; the publication types indicate U.S. government and NIH research support.

Do not conclude that TBI caused anxiety or PTSD in older adults. This was an observational billing-code study, it did not measure lifetime psychiatric history or illness severity, and PTSD diagnoses were very rare (218 before TBI and 269 after TBI).