Mortality and Associated Morbidities Following Traumatic Brain Injury in Older Medicare Statin Users

Association Between Stroke and Traumatic Brain Injury: A Systematic Review and Meta-Analysis

BACKGROUND

Stroke and traumatic brain injury (TBI) represent two major health concerns worldwide. There is growing evidence suggesting a potential association between TBI and stroke. In this systematic review and meta-analysis, we aim to explore the association between TBI and stroke risk, with a specific focus on overall stroke risk and subgroup variations based on stroke type, severity, and the post-TBI time period.

METHODS

PubMed, Web of Science (WOS), Scopus, and Cochrane Library were systematically searched for studies exploring the link between stroke and TBI. The pooled hazard ratios (HRs) with a 95% confidence interval (CI) were calculated. The Comprehensive Meta-Analysis (CMA) software was used for the analysis. Subgroup analyses were conducted based on stroke type, TBI severity, and post-TBI phase. The Newcastle-Ottawa Scale (NOS) was utilized for the quality assessment.

RESULTS

We included a total of 13 observational studies, with data from 8 studies used for quantitative analysis. A history of TBI was associated with a significantly higher odds of stroke compared to controls (HR = 2.3, 95% CI (1.79 to 2.958), p < 0.001). The risk was greater for hemorrhagic stroke (HR = 4.8, 95% CI (3.336 to 6.942), p < 0.001) than for ischemic stroke (HR = 1.56, 95% CI (1.28 to 1.9), p < 0.001). Both moderate-to-severe TBI (HR = 3.64, 95% CI (2.158 to 6.142), p < 0.001) and mild TBI (HR = 1.81, 95% CI (1.17 to 2.8), p = 0.007) were associated with a significantly higher risk of stroke. The risk was also higher in the early post-TBI phase (1-30 days) (HR = 4.155, 95% CI (2.25 to 7.67), p < 0.001) compared to later phases (HR = 1.68, 95% CI (1.089 to 2.59), p = 0.019) from 30 days to 1 year and (HR = 1.87, 95% CI (1.375 to 2.544), p < 0.001) after 1 year.

CONCLUSIONS

This systematic review confirms a significant association between TBI and an increased risk of stroke, regardless of TBI severity, type, or timing of stroke. The findings highlight the need for early monitoring and advocating preventive strategies for stroke in patients with a history of TBI.

Delayed simvastatin treatment improves neurological recovery after cryogenic traumatic brain injury through downregulation of ELOVL1 by inhibiting mTOR signaling

Statins are well-tolerated and widely available lipid-lowering medications with neuroprotective effects against traumatic brain injury (TBI). However, whether delayed statin therapy starting in the subacute phase promotes recovery after TBI is unknown. Elongation of the very long-chain fatty acid protein 1 (ELOVL1) is involved in astrocyte-mediated neurotoxicity, but its role in TBI and the relationship between ELOVL1 and statins are unclear. We hypothesized that delayed simvastatin treatment promotes neurological functional recovery after TBI by regulating the ELOVL1-mediated production of very long-chain fatty acids (VLCFAs). ICR male mice received daily intragastric administration of 1, 2 or 5 mg/kg simvastatin on Days 1-14, 3-14, 5-14, or 7-14 after cryogenic TBI (cTBI). The results showed that simvastatin promoted motor functional recovery in a dose-dependent manner, with a wide therapeutic window of at least 7 days postinjury. Meanwhile, simvastatin inhibited astrocyte and microglial overactivation and glial scar formation, and increased total dendritic length, neuronal complexity and spine density on day 14 after cTBI. The up-regulation of ELOVL1 expression and saturated VLCFAs concentrations in the cortex surrounding the lesion caused by cTBI was inhibited by simvastatin, which was related to the inhibition of the mTOR signaling. Overexpression of ELOVL1 in astrocytes surrounding the lesion using HBAAV2/9-GFAP-m-ELOVL1-3xFlag-EGFP partially attenuated the benefits of simvastatin. These results showed that delayed simvastatin treatment promoted functional recovery and brain tissue repair after TBI through the downregulation of ELOVL1 expression by inhibiting mTOR signaling. Astrocytic ELOVL1 may be a potential target for rehabilitation after TBI.

The protective effects of statins in traumatic brain injury

Traumatic brain injury (TBI), often referred to as the "silent epidemic", is the most common cause of mortality and morbidity worldwide among all trauma-related injuries. It is associated with considerable personal, medical, and economic consequences. Although remarkable advances in therapeutic approaches have been made, current treatments and clinical management for TBI recovery still remain to be improved. One of the factors that may contribute to this gap is that existing therapies target only a single event or pathology. However, brain injury after TBI involves various pathological mechanisms, including inflammation, oxidative stress, blood-brain barrier (BBB) disruption, ionic disturbance, excitotoxicity, mitochondrial dysfunction, neuronal necrosis, and apoptosis. Statins have several beneficial pleiotropic effects (anti-excitotoxicity, anti-inflammatory, anti-oxidant, anti-thrombotic, immunomodulatory activity, endothelial and vasoactive properties) in addition to promoting angiogenesis, neurogenesis, and synaptogenesis in TBI. Supposedly, using agents such as statins that target numerous and diverse pathological mechanisms, may be more effective than a single-target approach in TBI management. The current review was undertaken to investigate and summarize the protective mechanisms of statins against TBI. The limitations of conducted studies and directions for future research on this potential therapeutic application of statins are also discussed.

Antithrombotic and risk of hemorrhagic complications in over-60-year-olds after mild-minimal traumatic brain injury

PRIMARY OBJECTIVE

to identify if antithombotics are risk factors for intracereral lesion in older adults with minimal-mild traumatic brain injury (m-mTBI).

RESEARCH DESING

prospective cohort study.

METHODS AND PROCEDURES

We included 2,303 patients over 60 years arriving at our Emergency Department within 24 hours of an mTBI with a Glasgow Coma Scale (GSC) of 14-15. Data were gathered on clinical history, cranial CT scans, blood analyses.

OUTCOMES AND RESULTS

91.1% had an admission GSC score of 15, and 23.6% developed intracranial complications. In bivariate analyses, statins were associated with a 1.28-fold lower risk of IC. Hemorrhagic progression was 29.76-fold higher in patients receiving anticoagulants, with no difference among anticoagulant types. Male sex, GSC of 14, alcohol consumption, and the presence of tumor were risk factors for IC. In multivariate analysis, GSC of 14, alcohol consumption, and malignancy emerged as risk factors for these complications, neurological disease and diabetes as protective factors. After exclusion of neurological disease and diabetes from the multivariate model, a GSC of 14 showed the highest predictive capacity.

CONCLUSIONS

Antithrombotics intake are not risks factor for intracranial injury in minimal-mild brain injury trauma. Further research is needed taking account of their fragility and comorbidities.

HMG-CoA Reductase Inhibitors for Traumatic Brain Injury

Traumatic brain injuries (TBIs) are associated with high morbidity and mortality due to both the original insult as well as the destructive biological response that follows. Medical management aims to slow or even halt secondary neurological injury while simultaneously laying the groundwork for recovery. Statins are one class of medications that is showing increased promise in the management of TBI. Used extensively in cardiovascular disease, these drugs were originally developed as competitive inhibitors within the cholesterol production pipeline. They are now used in diverse disease states due to their pleiotropic effects on other biological processes such as inflammation and angiogenesis. Preclinical studies, retrospective reviews, and randomized clinical trials have shown a variety of benefits in the management of TBI, but to date, no large-scale randomized clinical trial has been performed. Despite this limitation, statins' early promise and well-tolerated side effect profile make them a promising new tool in the management of TBIs. More bench and clinical studies are needed to delineate proper treatment regimens as well as understand their true potential.

The neuroprotective effect of statin in traumatic brain injury: A systematic review

Despite recent encouraging pharmaceutical and technical breakthroughs in neurosurgical critical care, traumatic brain injury (TBI)-related mortality and morbidity remain substantial clinical issues. Medication of statins was revealed to enhance outcomes following TBI in animal research. In addition to their main role of decreasing serum cholesterol, statins decrease inflammation and enhance cerebral blood flow. However, research on the efficacy of statins in TBI is still limited. This systematic review was conducted to determine the efficacy of statins in enhancing the clinical outcomes of TBI individuals, and specifically investigate the optimal dose and form of statins. The databases of PubMed, DOAJ, EBSCO, and Cochrane were extensively researched. The date of publication within the last fifteen years was the inclusion criterion. Meta-analyses, clinical trials, and randomized controlled trials were prioritized forms of research publications. Ambiguous remarks, irrelevant correlations to the main issue, or a focus on disorders other than TBI were the exclusion criteria. Thirteen research were included in this study. Simvastatin, atorvastatin, and rosuvastatin were the main form of statins discussed in this study. Enhancement of the Glasgow Coma Scale, survival rates, hospital length of stay, and cognitive outcomes were revealed in this study. This study suggests either simvastatin 40 mg, atorvastatin 20 mg, or rosuvastatin 20 mg for 10 days as the optimal therapeutic forms and doses to be applied in the management of TBI. Pre-TBI statin use was linked to lower risk of mortality in TBI individuals compared to nonusers, whereas statin discontinuation was linked to an increase in mortality.

Associations of Preexisting Vascular Risk Factors With Outcomes After Traumatic Brain Injury: A TRACK-TBI Study

OBJECTIVE

To evaluate associations of preinjury vascular risk factors with traumatic brain injury (TBI) outcomes.

SETTING

The level 1 trauma center-based T ransforming R esearch a nd C linical K nowledge in TBI (TRACK-TBI) Study.

PARTICIPANTS

A total of 2361 acute TBI patients 18 years or older who presented to the emergency department within 24 hours of head trauma warranting clinical evaluation with a noncontrast head CT between February 26, 2014, and August 8, 2018.

DESIGN

A multicenter prospective cohort study.

MAIN MEASURES

Vascular risk factors (hypertension, diabetes, hyperlipidemia, and smoking) were assessed at baseline by self- or proxy-report and chart review. The primary outcome was the 6-month Glasgow Outcome Scale-Extended TBI version (GOSE-TBI). Secondary 6-month outcomes included the Rivermead Post-Concussion Symptoms Questionnaire (RPQ), the Satisfaction with Life Scale (SWLS), and the 18-item Brief Symptom Inventory Global Severity Index (BSI-18-GSI).

RESULTS

Mean age of participants was 42 years, 31% were women, and 16% were Black. Current smoking was the most common vascular risk factor (29%), followed by hypertension (17%), diabetes (8%), and hyperlipidemia (6%). Smoking was the only risk factor associated with worse scores on all 4 outcome indices. Hypertension and diabetes were associated with worse RPQ scores, and hypertension was associated with worse BSI-18-GSI scores (all P < .05). Compared with individuals with no vascular risk factors, individuals with 1 but not 2 or more vascular risk factors had significantly worse GOSE-TBI and SWLS scores, while a higher burden of vascular risk factors was significantly associated with worse RPQ and BSI-18-GSI scores.

CONCLUSION

Our study found that preinjury vascular risk factors, especially smoking, are associated with worse outcomes after TBI. Aggressive postinjury treatment of vascular risk factors may be a promising strategy to improve TBI outcomes.

Atorvastatin prevents endoplasmic reticulum stress-mediated apoptosis via the Nrf2/HO-1 signaling pathway in TBI mice

BACKGROUND

Our present study evaluated the neuroprotection effects of atorvastatin by inhibiting TBI-induced ER stress, as well as the potential role of the Nrf2/HO-1 pathway in experimental TBI.

METHODS

First, the mice were divided into four groups:sham, TBI, TBI+Vehicle and TBI+atorvastatin groups. The mice received atorvastatin (10 mg/kg/day) through intragastric gavage once a day for 3 days before TBI. In addition, Nrf2 WT and Nrf2 knockout mice were randomly divided into four groups: Nrf2+/+ TBI, Nrf2+/+ TBI+atorvastatin, Nrf2-/- TBI, and Nrf2-/- TBI+atorvastatin groups. Several neurobehavioral parameters were assessed post-TBI using mNSS, brain edema and the rotarod test, and the brain was isolated for molecular and biochemical analysis conducted through TUNEL staining and western blotting.     .

RESULTS

The results showed that atorvastatin treatment significantly improved neurological deficits, alleviated brain edema, and apoptosis caused by TBI. Western blotting analysis showed that atorvastatin significantly suppressed ER stress and its related apoptotic pathway after TBI, which may be associated with the further activation of the Nrf2/HO-1 pathway. However, compared with the Nrf2+/+ TBI+Vehicle group, Nrf2 deficiency further aggravated neurological deficits and promoted ER stress-mediated apoptosis induced by TBI. Interestingly, atorvastatin failed to improve neurological deficits but reversed apoptosis, and the loss of the beneficial properties of anti-ER stress in the Nrf2-/- TBI mice.      .

CONCLUSIONS

The results indicated that atorvastatin improves the neurologic functions and protects the brain from injury in the Nrf2+/+ TBI mice, primarily by counteracting ER stress-mediated apoptosis, which may be achieved through the activation of the Nrf2/HO-1 signaling pathway.

Statins and cognition: Modifying factors and possible underlying mechanisms

Statins are a class of widely prescribed drugs used to reduce low-density lipoprotein cholesterol (LDL-C) and important to prevent cardiovascular diseases (CVD). Most statin users are older adults with CVD, who are also at high risk of cognitive decline. It has been suggested that statins can alter cognitive performance, although their positive or negative effects are still debated. With more than 200 million people on statin therapy worldwide, it is crucial to understand the reasons behind discrepancies in the results of these studies. Here, we review the effects of statins on cognitive function and their association with different etiologies of dementia, and particularly, Alzheimer's disease (AD). First, we summarized the main individual and statin-related factors that could modify the cognitive effects of statins. Second, we proposed the underlying mechanisms for the protective and adverse effects of statins on cognitive performance. Finally, we discussed potential causes of discrepancies between studies and suggested approaches to improve future studies assessing the impact of statins on dementia risk and cognitive function.

Pharmacotherapy for mild traumatic brain injury: an overview of the current treatment options

INTRODUCTION

Accounting for 90% of all traumatic brain injuries (TBIs), mild traumatic brain injury (mTBI) is currently the most frequently seen type of TBI. Although most patients can recover from mTBI, some may suffer from prolonged symptoms for months to years after injury. Growing evidence indicates that mTBI is associated with neurodegenerative diseases including dementias and Parkinson's disease (PD). Pharmacological interventions are necessary to address the symptoms and avoid the adverse consequences of mTBI.

AREAS COVERED

To provide an overview of the current treatment options, the authors herein review the potential drugs to reduce the secondary damage and symptom-targeted therapy as well as the ongoing clinical trials about pharmacotherapy for mTBI.

EXPERT OPINION

There has been no consensus on the pharmacotherapy for mTBI. Several candidates including n-3 PUFAs, melatonin, NAC and statins show potential benefits in lessening the secondary injury and improving neurological deficits in pre-clinic studies, which, however, still need further investigation in clinical trials. The current pharmacotherapy for mTBI is empirical in nature and mainly targets to mitigate the symptoms. Well-designed clinical trials are now warranted to provide high level evidence.

Statins' Effect on Cognitive Outcome After Traumatic Brain Injury: A Systematic Review

Traumatic brain injury (TBI), also known as the "Silent Epidemic," is a growing devastating global health problem estimated to affect millions of individuals yearly worldwide with little public recognition, leading to many individuals living with a TBI-related disability. TBI has been associated with up to five times increase in the risk of dementia among multiple neurologic complications compared with the general population. Several therapies, including statins, have been tried and showed promising benefits for TBI patients. In this systematic review, we evaluated the recent literature that tested the role of statins on neurological and cognitive outcomes such as Alzheimer's Disease and non-Alzheimer's dementia in survivors of TBI with various severities. We conducted a systematic search on PubMed, PubMed Central, MEDLINE, and Google Scholar. MeSH terms and keywords were used to search for full-text randomized clinical trials (RCTs), cross-sectional, case-control, cohort studies, systematic reviews, and animal studies published in English. Inclusion and exclusion criteria were applied, and the articles were subjected to quality appraisal by two reviewers. Our data search retrieved 4948 nonduplicate records. A total of 18 studies were included - nine human studies, and nine animal laboratory trials - after meeting inclusion, eligibility, and quality assessment criteria. Simvastatin was the most tested statin, and the oral route of administration was the most used. Eight human studies showed a significant neuroprotective effect and improvement in the cognitive outcomes, including dementia. Four randomized clinical trials with 296 patients showed that statins play a neuroprotective role and improve cognitive outcomes through different mechanisms, especially their anti-inflammatory effect; they were shown to lower tumor necrosis factor (TNF)-α and C-reactive protein (CRP) levels. Also, they decreased axonal injury and cortical thickness changes. In addition, four cohort studies compared a total of 867.953 patients. One study showed a decrease in mortality in statin-treated patients (p=0.05). Another study showed a reduction in the incidence of Alzheimer's disease and related dementias (RR, 0.77; 95% CI, 0.73-0.81), while one study showed a decreased risk of dementia after concussions by 6.13% (p=0.001). On the other hand, one cohort study showed no significant difference with the use of statins. In eight animal trials, statins showed a significant neuroprotective effect, improved cognitive outcomes, and neurological functions. Different molecular and cellular mechanisms were suggested, including anti-inflammatory effects, promoting angiogenesis, neurogenesis, increasing cerebral blood flow, neurite outgrowth, promoting the proliferation and differentiation of neural stem cells, and reducing axonal injury. On the contrary, one study showed no benefit and actual adverse effect on the cognitive outcome. Most of the studies showed promising neuroprotective effects of statins in TBI patients. Cognitive outcomes, especially dementia, were improved. However, the optimal therapeutic protocol is still unknown. Thus, statins are candidates for more advanced studies to test their efficacy in preventing cognitive decline in patients with TBI.

Statins in Depression: An Evidence-Based Overview of Mechanisms and Clinical Studies

Background: Depression is a leading cause of disability, burdened by high levels of non-response to conventional antidepressants. Novel therapeutic strategies targeting non-monoaminergic pathways are sorely needed. The widely available and safe statins have several putative mechanisms of action, especially anti-inflammatory, which make them ideal candidates for repurposing in the treatment of depression. A large number of articles has been published on this topic. The aim of this study is to assess this literature according to evidence-based medicine principles to inform clinical practise and research. Methods: We performed a systematic review of the electronic databases MEDLINE, CENTRAL, Web of Science, CINAHL, and ClinicalTrials.gov, and an unstructured Google Scholar and manual search, until the 9th of April 2021, for all types of clinical studies assessing the effects of statins in depression. Results: Seventy-two studies were retrieved that investigated the effects of statins on the risk of developing depression or on depressive symptoms in both depressed and non-depressed populations. Fifteen studies specifically addressed the effects of statins on inflammatory-related symptoms of anhedonia, psychomotor retardation, anxiety, and sleep disturbances in depression. Most studies suggested a positive effect of statins on the occurrence and severity of depression, with fewer studies showing no effect, while a minority indicated some negative effects. Limitations: We provide a narrative report on all the included studies but did not perform any quantitative analysis, which limits the strength of our conclusions. Conclusions: Robust evidence indicates that statins are unlikely to lead to depressive symptoms in the general population. Promising data suggest a potential role for statins in the treatment of depression. Further clinical studies are needed, especially in specific subgroups of patients identified by pre-treatment assessments of inflammatory and lipid profiles.

The Effect of Oral Simvastatin on the Clinical Outcome of Patients with Severe Traumatic Brain Injury: A Randomized Clinical Trial

Background

Despite recent promising pharmacological and technological advances in neurosurgical intensive care, the overall TBI-related mortality and morbidity remain high and still pose a major clinical problem. The aim of this study was to evaluate the effect of oral simvastatin on the clinical outcome of patients with severe TBI.

Methods

In a double-blind placebo-controlled randomized clinical trial a total of 98 patients with severe TBI in Imam Khomeini Hospital in Sari, Iran, were evaluated. Patients who meet the inclusion criteria were randomly allocated into two groups (n=49). In addition to supportive therapies, the intervention group received oral simvastatin (40 mg, daily) for 10 days, and the control group received the placebo (10 days). Patients' Glasgow coma scale (GCS) score, in hospital mortality, duration of mechanical ventilation and length of ICU and neurosurgery ward stay were evaluated during three-time intervals (T1: admission, T2: discharge and T3: one month after discharge).

Results

The percentage of conscious patients was 18.9% (7 cases) in the simvastatin group and 3.1% (1 case) in controls (P=0.06) at T2. One month after discharge (T3) the proportion of conscious patients significantly increased in the simvastatin group compared to control group (64.9 % versus 28.1 %; P=0.002). There was no significant difference for the mean of GCS score between the simvastatin group and control group at T1 (6.41 ± 1.30 versus 6.41 ± 1.28, respectively; P = 0.98). However, the mean score of GCS in patients who received simvastatin was significantly greater than controls at T2 and T3 (p<0.05). There was no significant differences between two group in-terms of length of mechanical ventilation, ICU and neurosurgery ward stay.

Conclusion

According to the results of this study it seems that using simvastatin may be an effective and promising therapeutic modality for improving GCS score during TBI recovery.

Outcomes of Preinjury Use of Statins in Patients with Traumatic Brain Injury: A Systematic Review and Meta-analysis

BACKGROUND

No completely effective pharmacotherapies have been developed to improve the outcomes of traumatic brain injury (TBI). Given the reporting of cohort studies suggesting that preinjury statin use may reduce TBI-associated mortality, this study aimed to evaluate the effects of statin use in patients with TBI.

METHODS

This study was performed according to the PRISMA guidelines. The PubMed, Embase, Cochrane Central, Web of Science, and China National Knowledge Infrastructure databases were searched from inception until April 13, 2021, using a search strategy that included 2 main terms: "statins" and "traumatic brain injury." The outcomes were mortality, hospital length of stay, and intensive care unit length of stay, which were evaluated using a random-effects model and represented by the pooled risk ratio with 95% confidence intervals.

RESULTS

The search results identified 7 eligible studies, with a total of 111,935 patients with brain injury. Preinjury statin use in patients with TBI was associated with a significantly decreased risk of mortality compared with that in nonusers (risk ratio, 0.75; 95% confidence interval, 0.59-0.94; I² = 53%). Subgroup analysis showed that statin withdrawal might increase mortality. Sensitivity analysis showed that the results were stable and robust.

CONCLUSIONS

Preinjury statin use may contribute to mortality reduction in patients with TBI, whereas statin withdrawal might increase mortality. In clinical management, statin use should not be discontinued after TBI.

Stroke risk following traumatic brain injury: Systematic review and meta-analysis

Background

Traumatic brain injury is a global health problem; worldwide, >60 million people experience a traumatic brain injury each year and incidence is rising. Traumatic brain injury has been proposed as an independent risk factor for stroke.

Aims

To investigate the association between traumatic brain injury and stroke risk.

Summary of review

We undertook a systematic review of MEDLINE, EMBASE, CINAHL, and The Cochrane Library from inception to 4 December 2020. We used random-effects meta-analysis to pool hazard ratios for studies which reported stroke risk post-traumatic brain injury compared to controls. Searches identified 10,501 records; 58 full texts were assessed for eligibility and 18 met the inclusion criteria. The review included a large sample size of 2,606,379 participants from four countries. Six studies included a non-traumatic brain injury control group, all found traumatic brain injury patients had significantly increased risk of stroke compared to controls (pooled hazard ratio 1.86; 95% confidence interval 1.46–2.37). Findings suggest stroke risk may be highest in the first four months post-traumatic brain injury, but remains significant up to five years post-traumatic brain injury. Traumatic brain injury appears to be associated with increased stroke risk regardless of severity or subtype of traumatic brain injury. There was some evidence to suggest an association between reduced stroke risk post-traumatic brain injury and Vitamin K antagonists and statins, but increased stroke risk with certain classes of antidepressants.

Conclusion

Traumatic brain injury is an independent risk factor for stroke, regardless of traumatic brain injury severity or type. Post-traumatic brain injury review and management of risk factors for stroke may be warranted.

Review of the Protective Effects of Statins on Cognition

Elevated cholesterol is a major risk factor in the development of cardiovascular disease. Statins have proven to be effective in lowering low-density lipoprotein cholesterol as well as the incidence of cardiovascular events. As a result, statins are widely prescribed in the United States, with an estimated 35 million patients on statins. Many of these patients are older than age 65 and suffer from various comorbidities, including mild to severe cognitive impairment. Early studies looking at the effects of statins on cognition have shown that statin use may lead to mild reversible cognitive decline, although long-term studies have shown inconclusive findings. In recent years, studies have shown that the use of statins in certain groups of patients may lead to a reduction in the rate of cognitive decline. One hypothesis for this finding is that statin use can reduce the risk of cerebrovascular disease which may, in turn, reduce the risk of mild cognitive decline and dementia. With numerous patients currently prescribed statins and the likelihood that more patients will be prescribed the medication in the coming years, it is important to review the current literature to determine the association between statin use and cognitive decline, as well as determine how statins may be beneficial in preventing cognitive decline.

Association Between Statin Use and Risk of Dementia After a Concussion

Importance

Concussions are an acute injury that may lead to chronic disability, while statin use might improve neurologic recovery.

Objective

To test whether statin use is associated with an increased or decreased risk of subsequent dementia after a concussion.

Design, Setting, and Participants

Large extended population-based double cohort study in Ontario, Canada, from April 1, 1993, to April 1, 2013 (enrollment), and continued until March 31, 2016 (follow-up). Dates of analysis were April 28, 2014, through March 21, 2019. Participants were older adults diagnosed as having a concussion, excluding severe cases resulting in hospitalization, individuals with a prior diagnosis of dementia or delirium, and those who died within 90 days.

Exposure

Statin prescription within 90 days after a concussion.

Main Outcome and Measure

Long-term incidence of dementia.

Results

This study identified 28 815 patients diagnosed as having a concussion (median age, 76 years; 61.3% female), of whom 7058 (24.5%) received a statin, and 21 757 (75.5%) did not receive a statin. A total of 4727 patients subsequently developed dementia over a mean follow-up of 3.9 years, equal to an incidence of 1 case per 6 patients. Patients who received a statin had a 13% reduced risk of dementia compared with patients who did not receive a statin (relative risk, 0.87; 95% CI, 0.81-0.93; P < .001). The decreased risk of dementia associated with statin use applied to diverse patient groups, remained independent of other cardiovascular medication use, intensified over time, was distinct from the risk of subsequent depression, and was not observed in patients after an ankle sprain.

Conclusions and Relevance

In this study, older adults had a substantial long-term risk of dementia after a concussion, which was associated with a modest reduction among patients receiving a statin.