Anxiety and Posttraumatic Stress Disorder among Medicare Beneficiaries after Traumatic Brain Injury

Objective: To estimate rates of anxiety and posttraumatic stress disorder (PTSD) diagnoses after traumatic brain injury (TBI) among Medicare beneficiaries, quantify the increase in rates relative to the pre-TBI period, and identify risk factors for diagnosis of anxiety and PTSD. Participants: A total of 96 881 Medicare beneficiaries hospitalized with TBI between June 1, 2006 and May 31, 2010. Design: Retrospective cohort study. Measures: Diagnosis of anxiety (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] codes 300.0x) and/or PTSD (ICD-9-CM code 309.81). Results: After TBI, 16 519 (17%) beneficiaries were diagnosed with anxiety and 269 (0.3%) were diagnosed with PTSD. Rates of anxiety and PTSD diagnoses were highest in the first 5 months post-TBI and decreased over time. Pre-TBI diagnosis of anxiety disorder was significantly associated with post-TBI anxiety (risk ratio, 3.55; 95% confidence interval, 3.42-3.68) and pre-TBI diagnosis of PTSD was significantly associated with post-TBI PTSD (risk ratio 70.09; 95% confidence interval 56.29-111.12). Conclusion: This study highlights the increased risk of anxiety and PTSD after TBI. Routine screening for anxiety and PTSD, especially during the first 5 months after TBI, may help clinicians identify these important and treatable conditions, especially among patients with a history of psychiatric illness.