Objective: Depression is a common complication after traumatic brain injury (TBI). This study aimed to evaluate the risk of hyperlipidemia for new-onset depression after TBI and the role of statin medications using a longitudinal population database. Method: A matched longitudinal cohort study of 3,792 subjects (1,264 TBI patients with preexisting hyperlipidemia 272.1, 272.2, 272.4] and 2,528 age-and sex-matched TBI patients without hyperlipidemia) was conducted using the Taiwan Longitudinal Health Insurance Database from January 2001 to December 2008. The incidence and hazard ratios (HRs) for the development of new-onset depression (ICD-9-CM code: 296.2X-296.3X, 300.4, and 311.X) after TBI were compared between the 2 groups. Results: The incidence rate of depression in TBI with preexisting hyperlipidemia was 136.61 per 10,000 person-years. TBI patients with preexisting hyperlipidemia had a 1.72-fold increased incidence rate ratio compared with those without hyperlipidemia (P = .0056). A Cox model showed hyperlipidemia to be an independent predictor of depression (HR = 1.61; 95% CI, 1.03-2.53). TBI patients with hyperlipidemia who were not treated with statins experienced a 1.95-fold incidence risk ratio (P = .0017) and higher risk of new-onset depression (HR = 1.61; 95% CI, 1.03-2.53) compared to TBI patients without hyperlipidemia. Conclusions: Preexisting hyperlipidemia could be an independent predictor of new-onset depression in TBI patients, and TBI patients with preexisting hyperlipidemia who were not treated with statins presented a higher risk of new-onset depression than TBI patients without hyperlipidemia. Our findings may provide some insight into the important role of statin medications in the development of new-onset depression in patients with traumatic brain injury. T raumatic brain injury (TBI) is a leading cause of neurologic deficits, cognitive impairment, and psychiatric disorders in survivors.1 It has become a major public issue for an estimated 3.17 million individuals in the United States 2 and was associated with 3.39 times the medical costs in TBI patients with psychiatric disorders compared to those without psychiatric disorders.
3Among these psychiatric disorders, depression is the most common psychiatric complication of TBI and ranges from 6% to 77%, with variations according to the studied population and the diagnostic criteria or rating instruments used. [4][5][6][7] Depression is associated with a 3-fold increase of medical regimens in patients with chronic illness or comorbidities. the range of hyperlipidemia prevalence was from 19.9% to 33.5% among adults aged ≥ 20 years. Hyperlipidemia was also related to the risk of cardiovascular disease, 20 diabetes mellitus, 21 and hypertension, 22 which are all risk factors for depression. Furthermore, some evidence indicate that statin medications, an antihyperlipidemic agent, has neuroprotective effects on the hippocampus, which may be associated with the depression developed in TBI animal models. 23,24 Therefore, hyperlipidemia...