Effect of pharmacologic lipid lowering on health-related quality of life in older persons: results from the Cholesterol Reduction in Seniors Program (CRISP) Pilot Study

The Intersection of cerebral cholesterol metabolism and Alzheimer's disease: Mechanisms and therapeutic prospects

Alzheimer's disease (AD) is a common neurodegenerative disease in the elderly, the exact pathogenesis of which remains incompletely understood, and effective preventive and therapeutic drugs are currently lacking. Cholesterol plays a vital role in cell membrane formation and neurotransmitter synthesis, and its abnormal metabolism is associated with the onset of AD. With the continuous advancement of imaging techniques and molecular biology methods, researchers can more accurately explore the relationship between cholesterol metabolism and AD. Elevated cholesterol levels may lead to vascular dysfunction, thereby affecting neuronal function. Additionally, abnormal cholesterol metabolism may affect the metabolism of β-amyloid protein, thereby promoting the onset of AD. Brain cholesterol levels are regulated by multiple factors. This review aims to deepen the understanding of the subtle relationship between cholesterol homeostasis and AD, and to introduce the latest advances in cholesterol-regulating AD treatment strategies, thereby inspiring readers to contemplate deeply on this complex relationship. Although there are still many unresolved important issues regarding the risk of brain cholesterol and AD, and some studies may have opposite conclusions, further research is needed to enrich our understanding. However, these findings are expected to deepen our understanding of the pathogenesis of AD and provide important insights for the future development of AD treatment strategies targeting brain cholesterol homeostasis.

Acute Myocardial Infarction and Risk of Cognitive Impairment and Dementia: A Review

Cognitive impairment (CI) shares common cardiovascular risk factors with acute myocardial infarction (AMI), and is increasingly prevalent in our ageing population. Whilst AMI is associated with increased rates of CI, CI remains underreported and infrequently identified in patients with AMI. In this review, we discuss the evidence surrounding AMI and its links to dementia and CI, including pathophysiology, risk factors, management and interventions. Vascular dysregulation plays a major role in CI, with atherosclerosis, platelet activation, microinfarcts and perivascular inflammation resulting in neurovascular unit dysfunction, disordered homeostasis and a dysfunctional neurohormonal response. This subsequently affects perfusion pressure, resulting in enlarged periventricular spaces and hippocampal sclerosis. The increased platelet activation seen in coronary artery disease (CAD) can also result in inflammation and amyloid-β protein deposition which is associated with Alzheimer's Dementia. Post-AMI, reduced blood pressure and reduced left ventricular ejection fraction can cause chronic cerebral hypoperfusion, cerebral infarction and failure of normal circulatory autoregulatory mechanisms. Patients who undergo coronary revascularization (percutaneous coronary intervention or bypass surgery) are at increased risk for post-procedure cognitive impairment, though whether this is related to the intervention itself or underlying cardiovascular risk factors is debated. Mortality rates are higher in dementia patients with AMI, and post-AMI CI is more prevalent in the elderly and in patients with post-AMI heart failure. Medical management (antiplatelet, statin, renin-angiotensin system inhibitors, cardiac rehabilitation) can reduce the risk of post-AMI CI; however, beta-blockers may be associated with functional decline in patients with existing CI. The early identification of those with dementia or CI who present with AMI is important, as subsequent tailoring of management strategies can potentially improve outcomes as well as guide prognosis.

The effects of statin monotherapy on depressive symptoms: A systematic review and meta-analysis

INTRODUCTION

Statins have been proposed as a strategy for treating depression, but their benefit in the absence of concurrent antidepressant treatment is unclear. This meta-analysis investigated the antidepressant effects of statin monotherapy in the general population.

METHODS

We conducted a literature search of randomised controlled trials using any statin monotherapy versus any control condition for depressive symptoms. Our primary efficacy outcome was the mean value on any standardised scale for depression at study endpoint. We also measured efficacy at three further timepoints (<6 months, 6-12 months, >12 months), as well as acceptability, tolerability, and safety. Respectively, continuous and dichotomous outcomes were computed using standardised mean difference (SMD) or relative risk (RR) with 95% confidence intervals (CI) using a random-effect model.

RESULTS

Pooled analyses did not show that statin monotherapy improves depressive symptoms at endpoint (N = 2712 SMD = -0.18; 95% CI = -0.41 to 0.04), nor at any other specific timepoint. No difference between statins and control was identified for any of the other outcome measures.

DISCUSSION

These results differ from those of previous meta-analyses and, compounded by more recently available evidence, suggest that statins may not have intrinsic antidepressant properties, but may be useful for the management of depression in add-on to antidepressants.

LIMITATIONS

Data from heterogeneous populations and using different statins were pooled, though several sensitivity and subgroup analyses were performed to account for that. PROSPERO registration: CRD42022306653. https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=306653.

Trials and Treatments for Vascular Brain Health: Risk Factor Modification and Cognitive Outcomes

There is robust evidence linking vascular health to brain health, cognition, and dementia. In this article, we present evidence from trials of vascular risk factor treatment on cognitive outcomes. We summarize findings from randomized controlled trials of antihypertensives, lipid-lowering medications, diabetes treatments (including antidiabetic drugs versus placebo, and intensive versus standard glycemic control), and multidomain interventions (that target several domains simultaneously such as control of vascular and metabolic factors, nutrition, physical activity, and cognitive stimulation etc). We report that evidence on the efficacy of vascular risk reduction interventions is promising, but not yet conclusive, and several methodological limitations hamper interpretation. Evidence mainly comes from high-income countries and, as cognition and dementia have not been the primary outcomes of many trials, evaluation of cognitive changes have often been limited. As the cognitive aging process occurs over decades, it is unclear whether treatment during the late-life window is optimal for dementia prevention, yet older individuals have been the target of most trials thus far. Further, many trials have not been powered to explore interactions with modifiers such as age, race, and apolipoprotein E, even though sub-analyses from some trials indicate that the success of interventions differs depending on patient characteristics. Due to the complex multifactorial etiology of dementia, and variations in risk factors between individuals, multidomain interventions targeting several risk factors and mechanisms are likely to be needed and the long-term sustainability of preventive interventions will require personalized approaches that could be facilitated by digital health tools. This is especially relevant during the coronavirus disease 2019 (COVID-19) pandemic, where intervention strategies will need to be adapted to the new normal, when face-to-face engagement with participants is limited and public health measures may create changes in lifestyle that affect individuals’ vascular risk profiles and subsequent risk of cognitive decline.

Update on Statin Treatment in Patients with Neuropsychiatric Disorders

Statins are widely accepted as first-choice agents for the prevention of lipid-related cardiovascular diseases. These drugs have both anti-inflammatory and anti-oxidant properties, which may also make them effective as potential treatment marked by perturbations in these pathways, such as some neuropsychiatric disorders. In this narrative review, we have investigated the effects of statin therapy in individuals suffering from major depressive disorder (MDD), schizophrenia, anxiety, obsessive-compulsive disorder (OCD), bipolar disorder (BD), delirium, and autism spectrum disorders using a broad online search of electronic databases. We also explored the adverse effects of these drugs to obtain insights into the benefits and risks associated with their use in the treatment of these disorders. Lipophilic statins (including simvastatin) because of better brain penetrance may have greater protective effects against MDD and schizophrenia. The significant positive effects of statins in the treatment of anxiety disorders without any serious adverse side effects were shown in numerous studies. In OCD, BD, and delirium, limitations, and contradictions in the available data make it difficult to draw conclusions on any positive effect of statins. The positive effects of simvastatin in autism disorders have been evaluated in only a small number of clinical trials. Although some studies showed positive effect of statins in some neuropsychiatric disorders, further prospective studies are needed to confirm this and define the most effective doses and treatment durations.

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.

Major Depressive Disorder in Older Patients as an Inflammatory Disorder: Implications for the Pharmacological Management of Geriatric Depression

Depression is a common and highly disabling condition in older adults. It is a heterogenous disorder and there is emerging evidence of a link between inflammation and depression in older patients, with a possible inflammatory subtype of depression. Persistent low-level inflammation, from several sources including psychological distress and chronic disease, can disrupt monoaminergic and glutaminergic systems to create dysfunctional brain networks. Despite the evidence for the role of inflammation in depression, there is insufficient evidence to recommend use of any putative anti-inflammatory agent in the treatment of depression in older adults at this stage. Further characterisation of markers of inflammation and stratification of participants with elevated rates of inflammatory markers in treatment trials is needed.

Statin use and depression risk: A systematic review and meta-analysis

BACKGROUND

Evidence regarding whether statin use is associated with depression is inconsistent. Therefore, we performed a meta-analysis to investigate this association.

METHODS

We searched PubMed, the Cochrane Library, and the EMBASE database, limiting the search to human patients and articles written in English and published by March 31, 2020. The Newcastle-Ottawa scale for observational studies was used to assess study quality. All included studies were evaluated by 2 reviewers independently; any discrepancies were resolved through discussion. Because of the heterogeneity of study populations, a random effects model was used to calculate the pooled effect size. Statistical heterogeneity across studies was assessed using the I² statistic. All analyses were performed using RevMan5 and Comprehensive Meta-Analysis software.

RESULTS

A total of 13 observational (9 cohort, 3 case-control, and 1 cross-sectional) studies conducted in 11 countries and enrolling 5 035 070 participants were included. Substantial statistical heterogeneity was discovered (I², 83%). Overall, use of statins was not associated with depression after trim and fill analysis (adjusted pooled odds ratio [OR], 0.87; 95% CI, 0.74-1.02). The finding was consistent in the subgroup analysis, except for studies published before 2013, showing statin use was associated with a lower risk of depression.

LIMITATIONS

High heterogeneity and asymmetry funnel plot of ORs from these studies were observed.

CONCLUSIONS

This meta-analysis revealed statin use was not associated with depression. However, high heterogeneity was observed between identified studies, and results were inconsistent in the subgroups of studies published before 2013.

Impact of Lowering Low-Density Lipoprotein Cholesterol with Contemporary Lipid-Lowering Medicines on Cognitive Function: A Systematic Review and Meta-Analysis

PURPOSE

To evaluate the potential association between the lowering of low-density lipoprotein cholesterol (LDL-C) with contemporary lipid-lowering medicines and cognitive function.

METHODS

Randomized controlled trials (RCTs) in databases including PubMed, Embase, and the Web of Science and all databases in the Cochrane Library and ClinicalTrials.gov were collected from inception to January 1, 2020. The cognitive function of patients receiving proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, statins and ezetimibe was evaluated using meta-analysis.

RESULTS

A total of 2910 studies were obtained from databases and other sources. Thirty-three studies were selected by screening, including 11 studies on alirocumab, 9 studies on evolocumab, 11 studies on statins and 2 studies on ezetimibe. In our study, a total of 128,691 patients with no cognitive impairment were divided into an intervention group (66,330 patients) and a control group (62,361 patients). The data were subjected to a random-effects model or a fixed-effects model for meta-analysis. The contemporary lipid-lowering medicines significantly reduced LDL-C in terms of both percentage (WMD: -45.06%, 95% CI -50.12% to -40.00%, P < 0.001) and absolute value (WMD: -64.01 mg/dL, 95% CI -72.25 to -55.78, P < 0.001). Compared with the control group, patients receiving treatment with contemporary lipid-lowering medicines did not show a significant difference in the rate of neurocognitive disorder (RR: 1.02, 95% CI 0.90 to 1.16, I² = 0.0%, p = 0.696). Subgroup analysis was performed according to the intervention and LDL-C stratification. The result of this subgroup analysis was consistent with the main findings. Regarding global cognitive performance, no difference in major cognition was found among the pooled data (SMD: 0.02, 95% CI -0.01 to 0.04, P = 0.002), except for psychomotor speed (SMD: 0.09, 95% CI 0.02 to 0.16, P = 0.0024).

CONCLUSIONS

Contemporary lipid-lowering medicines were not associated with cognitive impairment in RCTs. A low LDL-C level did not influence the incidence of cognitive disorder or global cognitive performance.

Association of blood lipids, atherosclerosis and statin use with dementia and cognitive impairment after stroke: A systematic review and meta-analysis

BACKGROUND

Trial and observational evidence is conflicting in terms of the association of blood lipids, atherosclerosis and statin use with dementia and cognitive impairment in the general population. It is uncertain whether the associations occur in stroke patients, who are at known higher risk of cognitive decline. This systematic review was to synthesize the evidence for these associations among stroke patients.

METHODS

MEDLINE, EMBASE, the Cochrane Library and trial registries were searched. We included randomized controlled trials (RCTs) or observational cohort studies conducted among patients with stroke and reported on the association of blood lipids, atherosclerosis or statin use with dementia or cognitive impairment. Meta-analysis was conducted separately for crude and maximally adjusted odds ratios (ORs) and hazard ratios (HRs).

RESULTS

Of 18,026 records retrieved, 56 studies (one RCT and 55 cohort studies) comprising 38,423 stroke patients were included. For coronary heart disease, the pooled OR of dementia and cognitive impairment was 1.32 (95%CI 1.10-1.58, n = 15 studies, I² = 0%) and 1.23 (95%CI 0.99-1.54, n = 14, I² = 26.9%), respectively. Peripheral artery disease was associated with dementia (OR 3.59, 95%CI 1.47-8.76, n = 2, I² = 0%) and cognitive impairment (OR 2.70, 95%CI 1.09-6.69, n = 1). For carotid stenosis, the pooled OR of dementia and cognitive impairment was 2.67 (95%CI 0.83-8.62, n = 3, I² = 77.9%) and 3.34 (95%CI 0.79-14.1, n = 4, I² = 96.6%), respectively. For post-stroke statin use, the pooled OR of dementia and cognitive impairment was 0.89 (95%CI 0.65-1.21, n = 1) and 0.56 (95%CI 0.46-0.69, n = 3, I² = 0%), respectively. No association was observed for hypercholesterolemia. These results were mostly consistent with adjusted ORs or HRs, which were reported from limited evidence.

CONCLUSION

Atherosclerosis was associated with an increased risk of post-stroke dementia. Post-stroke statin use was associated with decreased risk of cognitive impairment. To confirm whether or not statins confer advantages in the post-stroke population in terms of preventing cognitive decline over and above their known effectiveness in reducing risk of further vascular events, further stroke trials including cognitive assessment and observational analyses adjusted for key confounders, focusing on key subgroups or statin use patterns are required.

Alterations in cholesterol metabolism as a risk factor for developing Alzheimer's disease: Potential novel targets for treatment

Alzheimer's disease (AD) is the most common form of dementia and it is characterized by the deposition of amyloid-β (Aβ) plaques and neurofibrillary tangles in the brain. However, the complete pathogenesis of the disease is still unknown. High level of serum cholesterol has been found to positively correlate with an increased risk of dementia and some studies have reported a decreased prevalence of AD in patients taking cholesterol-lowering drugs. Years of research have shown a strong correlation between blood hypercholesterolemia and AD, however cholesterol is not able to cross the Blood Brain Barrier (BBB) into the brain. Cholesterol lowering therapies have shown mixed results in cognitive performance in AD patients, raising questions of whether brain cholesterol metabolism in the brain should be studied separately from peripheral cholesterol metabolism and what their relationship is. Unlike cholesterol, oxidized cholesterol metabolites known as oxysterols are able to cross the BBB from the circulation into the brain and vice-versa. The main oxysterols present in the circulation are 24S-hydroxycholesterol and 27-hydroxycholesterol. These oxysterols and their catalysing enzymes have been found to be altered in AD brains and there is evidence indicating their influence in the progression of the disease. This review gives a broad perspective on the relationship between hypercholesterolemia and AD, cholesterol lowering therapies for AD patients and the role of oxysterols in pathological and non-pathological conditions. Also, we propose cholesterol metabolites as valuable targets for prevention and alternative AD treatments.

Efficacy of anti-inflammatory treatment on major depressive disorder or depressive symptoms: meta-analysis of clinical trials

BACKGROUND

No study has gathered evidence from all randomized clinical trials (RCTs) with anti-inflammatory drugs measuring antidepressant effects including a detailed assessment of side-effects and bias.

METHODS

We performed a systematic review identifying RCTs published prior to January 1, 2018, studying antidepressant treatment effects and side-effects of pharmacological anti-inflammatory intervention in adults with major depressive disorder (MDD) or depressive symptoms. Outcomes were depression scores after treatment, remission, response, and side-effects. Pooled standard mean differences (SMD) and risk ratios (RR) including 95% confidence intervals (95%-CI) were calculated.

RESULTS

We identified 36 RCTs, whereof 13 investigated NSAIDs (N = 4214), 9 cytokine inhibitors (N = 3345), seven statins (N = 1576), 3 minocycline (N = 151), 2 pioglitazone (N = 77), and 2 glucocorticoids (N = 59). Anti-inflammatory agents improved depressive symptoms compared to placebo as add-on in patients with MDD (SMD = -0.64; 95%-CI = -0.88, -0.40; I²  = 51%; N = 597) and as monotherapy (SMD = -0.41; 95%-CI = -0.60, -0.22; I²  = 93%, N = 8825). Anti-inflammatory add-on improved response (RR = 1.76; 95%-CI = 1.44-2.16; I²  = 16%; N = 341) and remission (RR = 2.14; 95%-CI = 1.03-4.48; I²  = 57%; N = 270). We found a trend toward an increased risk for infections, and all studies showed high risk of bias.

CONCLUSION

Anti-inflammatory agents improved antidepressant treatment effects. Future RCTs need to include longer follow-up, identify optimal doses and subgroups of patients that can benefit from anti-inflammatory intervention.

Evidence and mechanisms for statin-induced cognitive decline

INTRODUCTION

Statin drugs have become the most highly prescribed drugs for cardiovascular disease. However, there is disagreement as to the existence of adverse effects of statin administration on cognitive function. Therefore, it is important to better understand the effects of statins on cognition and possible mechanisms of these effects. Areas covered: We analyzed relevant studies of the relationship between cognitive performance and statin and usage. We included articles published between 2018 and 1992. We identified three randomized trials, one observational study and 66 case reports that provided credible evidence of statin-induced cognitive impairment. We also identified seven randomized trials and two observational studies reporting no significant evidence of statin-induced cognitive impairment. Expert opinion: We found methodological differences that may have contributed to the divergence of these results. Evaluation of all these studies indicated that statin-associated cognitive decline is a real entity. Likely mechanisms to explain the adverse effects include 1. Reduction of synthesis of coenzyme Q10 with consequent increasing oxidative stress and reduction of cerebral energy production; 2. Depletion of central nervous system myelin by inhibition of cholesterol synthesis. We conclude that statin-induced cognitive decline does exist, needs to be better recognized and requires more studies of prevention and treatment.

Statin treatment and the risk of depression

BACKGROUND

The effect of statin treatment on the risk of developing depression remains unclear. Therefore, we assessed the association between statin treatment and depression in a nationwide register-based cohort study with up to 20 years of follow up.

METHODS

We identified all statin users in the period from 1996 to 2013 among individuals born in Denmark between 1920 and 1983. One non-user was matched to each statin user based on age, sex and a propensity score taking several potential confounders into account. Using Cox regression we investigated the association between statin use and: (I) redemption of prescriptions for antidepressants, (II) redemption of prescriptions for any other drug, (III) depression diagnosed at psychiatric hospitals, (IV) cardiovascular mortality and (V) all-cause mortality.

RESULTS

A total of 193,977 statin users and 193,977 non-users were followed for 2,621,282 person-years. Statin use was associated with (I) increased risk of antidepressant use (hazard rate ratio (HRR) = 1.33; 95% confidence interval (95%-CI) = 1.31-1.36), (II) increased risk of any other prescription drug use (HRR = 1.33; 95%-CI = 1.31-1.35), (III) increased risk of receiving a depression diagnosis (HRR = 1.22, 95%-CI = 1.12-1.32) - but not after adjusting for antidepressant use (HRR = 1.07, 95%-CI = 0.99-1.15), (IV) reduced cardiovascular mortality (HRR = 0.92, 95%-CI = 0.87-0.97) and (V) reduced all-cause mortality (HRR = 0.90, 95%-CI = 0.88-0.92).

CONCLUSIONS

These results suggest that the association between statin treatment and antidepressant use is unspecific (equivalent association between statins and most other drugs) and that the association between statin use and depression diagnoses is mediated by residual confounding, bias or by downstream effects of the statin prescription (seeing a physician more often).

PCSK9 and neurocognitive function: Should it be still an issue after FOURIER and EBBINGHAUS results?

The serine protease proprotein convertase subtilisin/kexin type 9 (PCSK9) modulates the levels of low-density lipoprotein cholesterol and cardiovascular risk. Potential risks of adverse neurological effects of intensive lipid-lowering treatment have been hypothesized, as cholesterol is a component of the central nervous system. Moreover, several observations suggest that PCSK9 might play a role in neurogenesis, neuronal migration and apoptosis. In rodents, increased expression of PCSK9 has been detected in specific areas of the central nervous system during embryonic development; also, PCSK9 modulates low-density lipoprotein receptor levels in the ischemic brain areas. Despite a putative participation of PCSK9 in nervous system physiology, the absence of PCSK9 in knockout mice or in humans with loss-of-function mutations of PCSK9 gene has not been linked to neurological alterations. In recent years, some concerns have been raised about the potential neurological side effects of cholesterol-lowering treatments and, more specifically of PCSK9 inhibitors. In this review, the evidence regarding the function of PCSK9 in neuron differentiation, apoptosis, and migration and in nervous system development and latest clinical trials evaluating the effects of PCSK9 inhibitors on neurocognitive function will be described.

Association of Microvascular Dysfunction With Late-Life Depression: A Systematic Review and Meta-analysis

Importance

The etiologic factors of late-life depression are still poorly understood. Recent evidence suggests that microvascular dysfunction is associated with depression, which may have implications for prevention and treatment. However, this association has not been systematically reviewed.

Objective

To examine the associations of peripheral and cerebral microvascular dysfunction with late-life depression.

Data Sources

A systematic literature search was conducted in MEDLINE and EMBASE for and longitudinal studies published since inception to October 16, 2016, that assessed the associations between microvascular dysfunction and depression.

Study Selection

Three independent researchers performed the study selection based on consensus. Inclusion criteria were a study population 40 years of age or older, a validated method of detecting depression, and validated measures of microvascular function.

Data Extraction and Synthesis

This systematic review and meta-analysis has been registered at PROSPERO (CRD42016049158) and is reported in accordance with the PRISMA and MOOSE guidelines. Data extraction was performed by an independent researcher.

Main Outcomes and Measures

The following 5 estimates of microvascular dysfunction were considered in participants with or without depression: plasma markers of endothelial function, albuminuria, measurements of skin and muscle microcirculation, retinal arteriolar and venular diameter, and markers for cerebral small vessel disease. Data are reported as pooled odds ratios (ORs) by use of the generic inverse variance method with the use of random-effects models.

Results

A total of 712 studies were identified; 48 were included in the meta-analysis, of which 8 described longitudinal data. Data from 43 600 participants, 9203 individuals with depression, and 72 441 person-years (mean follow-up, 3.7 years) were available. Higher levels of plasma endothelial biomarkers (soluble intercellular adhesion molecule-1: OR, 1.58; 95% CI, 1.28-1.96), white matter hyperintensities (OR, 1.29; 95% CI, 1.19-1.39), cerebral microbleeds (OR, 1.18; 95% CI, 1.03-1.34), and cerebral (micro)infarctions (OR, 1.30; 95% CI, 1.21-1.39) were associated with depression. Among the studies available, no significant associations of albuminuria and retinal vessel diameters with depression were reported. Longitudinal data showed a significant association of white matter hyperintensities with incident depression (OR, 1.19; 95% CI, 1.09-1.30).

Conclusions and Relevance

This meta-analysis shows that both the peripheral and cerebral forms of microvascular dysfunction are associated with higher odds of (incident) late-life depression. This finding may have clinical implications because microvascular dysfunction might provide a potential target for the prevention and treatment of depression.

Interpretation of the evidence for the efficacy and safety of statin therapy

This Review is intended to help clinicians, patients, and the public make informed decisions about statin therapy for the prevention of heart attacks and strokes. It explains how the evidence that is available from randomised controlled trials yields reliable information about both the efficacy and safety of statin therapy. In addition, it discusses how claims that statins commonly cause adverse effects reflect a failure to recognise the limitations of other sources of evidence about the effects of treatment. Large-scale evidence from randomised trials shows that statin therapy reduces the risk of major vascular events (ie, coronary deaths or myocardial infarctions, strokes, and coronary revascularisation procedures) by about one-quarter for each mmol/L reduction in LDL cholesterol during each year (after the first) that it continues to be taken. The absolute benefits of statin therapy depend on an individual's absolute risk of occlusive vascular events and the absolute reduction in LDL cholesterol that is achieved. For example, lowering LDL cholesterol by 2 mmol/L (77 mg/dL) with an effective low-cost statin regimen (eg, atorvastatin 40 mg daily, costing about £2 per month) for 5 years in 10 000 patients would typically prevent major vascular events from occurring in about 1000 patients (ie, 10% absolute benefit) with pre-existing occlusive vascular disease (secondary prevention) and in 500 patients (ie, 5% absolute benefit) who are at increased risk but have not yet had a vascular event (primary prevention). Statin therapy has been shown to reduce vascular disease risk during each year it continues to be taken, so larger absolute benefits would accrue with more prolonged therapy, and these benefits persist long term. The only serious adverse events that have been shown to be caused by long-term statin therapy-ie, adverse effects of the statin-are myopathy (defined as muscle pain or weakness combined with large increases in blood concentrations of creatine kinase), new-onset diabetes mellitus, and, probably, haemorrhagic stroke. Typically, treatment of 10 000 patients for 5 years with an effective regimen (eg, atorvastatin 40 mg daily) would cause about 5 cases of myopathy (one of which might progress, if the statin therapy is not stopped, to the more severe condition of rhabdomyolysis), 50-100 new cases of diabetes, and 5-10 haemorrhagic strokes. However, any adverse impact of these side-effects on major vascular events has already been taken into account in the estimates of the absolute benefits. Statin therapy may cause symptomatic adverse events (eg, muscle pain or weakness) in up to about 50-100 patients (ie, 0·5-1·0% absolute harm) per 10 000 treated for 5 years. However, placebo-controlled randomised trials have shown definitively that almost all of the symptomatic adverse events that are attributed to statin therapy in routine practice are not actually caused by it (ie, they represent misattribution). The large-scale evidence available from randomised trials also indicates that it is unlikely that large absolute excesses in other serious adverse events still await discovery. Consequently, any further findings that emerge about the effects of statin therapy would not be expected to alter materially the balance of benefits and harms. It is, therefore, of concern that exaggerated claims about side-effect rates with statin therapy may be responsible for its under-use among individuals at increased risk of cardiovascular events. For, whereas the rare cases of myopathy and any muscle-related symptoms that are attributed to statin therapy generally resolve rapidly when treatment is stopped, the heart attacks or strokes that may occur if statin therapy is stopped unnecessarily can be devastating.

Remembering Statins: Do Statins Have Adverse Cognitive Effects?

The issue of statin-associated cognitive impairment has been a hot topic among both patients and health care providers, especially since the U.S. Food and Drug Administration (FDA) issued a statement regarding rare postmarketing reports of ill-defined cognitive impairment associated with statin use. This statement was based on case reports, and no objective measures of cognitive function were used. Nevertheless, many patients at high risk of cardiovascular disease have expressed concerns about possible cognitive decline and may have opted to forgo statin therapy. In this overview, the evidence leading to the statement by the FDA is reviewed. Potential mechanisms of the effect of LDL cholesterol reduction and statin therapy on cognition are discussed. Evidence from observational and prospective randomized trials is summarized, leading to the conclusion that as for now, there is no good evidence that statins cause cognitive impairment to a significant degree. Reported cases seem to be rare, and a causal relationship has not been established.

Statins for the treatment of depression: A meta-analysis of randomized, double-blind, placebo-controlled trials

BACKGROUND

In epidemiological studies, statins appear to benefit mood, and there are now some randomized controlled trials examining the efficacy of statins. However, the role of statins in depression remains uncertain. Thus the aim of this paper was to assess the effect of statins on depressive symptoms by performing a meta-analysis of all double-blind, randomized, placebo controlled clinical trials (RCT) conducted in subjects with depression.

METHODS

A systematic search was executed using PubMed and ClinicalTrials.gov in November 30th, 2015 for all double-blind, RCT of statins versus placebo in persons with depressive symptoms. Sixty-seven potential articles were identified through search of electronic databases, of those three met inclusion criteria and were included in the meta-analysis. The outcome measure was change in Hamilton Depression Rating Scale (HDRS) scores associated with statin use. A meta-analysis was conducted and standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated. GRADE was used to assess study quality.

RESULTS

The three articles included provided data on 165 participants with moderate to severe depression. Of these, 82 were randomized to statins as an adjuvant therapy to antidepressant treatment (i.e., citalopram or fluoxetine) and 83 to the placebo arm. All studies were double-blind RCTs, with a follow-up of 6-12 weeks. The statin agents evaluated were lovastatin, atorvastatin, and simvastatin. When compared to placebo, statins, as add-on to treatment as usual, largely improved depressive symptoms as assessed by the HDRS (SMD=-0.73, 95% IC -1.04 to -0.42, p<0.001, 3 between-group comparisons, n=165). No serious adverse effects were reported.

CONCLUSIONS

Our results suggest that adjunctive treatment with statins could be useful for the treatment of depressive symptoms. Additional double-blind, randomised, placebo-controlled trials are necessary to settle the matter.

Endocrine Risk Factors for Cognitive Impairment

Cognitive impairment, including Alzheimer's disease and other kinds of dementia, is a major health problem in older adults worldwide. Although numerous investigators have attempted to develop effective treatment modalities or drugs, there is no reasonably efficacious strategy for preventing or recovering from cognitive impairment. Therefore, modifiable risk factors for cognitive impairment have received attention, and the growing literature of metabolic risk factors for cognitive impairment has expanded from epidemiology to molecular pathogenesis and therapeutic management. This review focuses on the epidemiological evidence for the association between cognitive impairment and several endocrine risk factors, including insulin resistance, dyslipidemia, thyroid dysfunction, vitamin D deficiency, and subclinical atherosclerosis. Researches suggesting possible mechanisms for this association are reviewed. The research investigating modifiable endocrine risk factors for cognitive impairment provides clues for understanding the pathogenesis of cognitive impairment and developing novel treatment modalities. However, so far, interventional studies investigating the beneficial effect of the "modification" of these "modifiable risk factors" on cognitive impairment have reported variable results. Therefore, well-designed, randomized prospective interventional studies are needed.

Current drug treatment of hyperlipidemia in older adults

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of death, especially in older adults. Managing modifiable risk factors (e.g., hyperlipidemia, hypertension) remains the primary approach to prevent ASCVD events and ASCVD-related mortality. Statins are generally considered one of the most effective approaches to reduce ASCVD risk, especially for secondary prevention, yet remain underutilized in older adults. The evidence to support statin therapy in older adults is less robust than in their younger counterparts, especially in individuals aged 75 years and older. Recent lipid guidelines have raised this concern, yet statin therapy is recommended in 'at risk' older adults. Determining which older adults should receive statin therapy for primary prevention of ASCVD is challenging, as the currently available risk estimation tools are of limited use in those aged over 75 years. Furthermore, non-statin therapies have been de-emphasized in recent clinical practice guidelines and remain understudied in the older adult population. This is unfortunate given that older adults are less likely to tolerate moderate- to high-intensity statins. Non-statin therapies could be viable options in this population if more was understood about their ability to lower ASCVD risk and safety profiles. Nevertheless, lipid-lowering agents remain an integral component of the overall strategy to reduce atherogenic burden in older adults. Future research in this area should aim to enroll more older adults in clinical trials, determine the utility of ASCVD risk estimation for primary prevention, and investigate the role of non-statin therapies in this population.

Statins and Cognitive Side Effects: What Cardiologists Need to Know

Statins are widely used in secondary and primary prevention of atherosclerotic cardiovascular disease. They reduce cardiovascular events and mortality, and have an excellent safety record. Recent case reports suggest a possible association between statins and adverse effects on cognition. This article reviews recent literature related to statins and cognition and provides recommendations to clinicians. Cognitive considerations should not play a role in decision making for most patients for whom statins are indicated. Future trials of statin, or any novel antilipemic agent should include systematic assessment of cognition.

Statins for the prevention of dementia

BACKGROUND

This is an update of a Cochrane review first published in 2001 and then updated in 2009. Vascular risk factors including high cholesterol levels increase the risk of dementia due to Alzheimer's disease and of vascular dementia. Some observational studies have suggested an association between statin use and lowered incidence of dementia.

OBJECTIVES

To evaluate the efficacy and safety of statins for the prevention of dementia in people at risk of dementia due to their age and to determine whether the efficacy and safety of statins for this purpose depends on cholesterol level, apolipoprotein E (ApoE) genotype or cognitive level.

SEARCH METHODS

We searched ALOIS (the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group), The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS, ClinicalTrials.gov and the World Health Organization (WHO) Portal on 11 November 2015.

SELECTION CRITERIA

We included double-blind, randomised, placebo-controlled trials in which statins were administered for at least 12 months to people at risk of dementia.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included two trials with 26,340 participants aged 40 to 82 years of whom 11,610 were aged 70 or older. All participants had a history of, or risk factors for, vascular disease. The studies used different statins (simvastatin and pravastatin). Mean follow-up was 3.2 years in one study and five years in one study. The risk of bias was low. Only one study reported on the incidence of dementia (20,536 participants, 31 cases in each group; odds ratio (OR) 1.00, 95% confidence interval (CI) 0.61 to 1.65, moderate quality evidence, downgraded due to imprecision). Both studies assessed cognitive function, but at different times using different scales, so we judged the results unsuitable for a meta-analysis. There were no differences between statin and placebo groups on five different cognitive tests (high quality evidence). Rates of treatment discontinuation due to non-fatal adverse events were less than 5% in both studies and there was no difference between statin and placebo groups in the risk of withdrawal due to adverse events (26,340 participants, 2 studies, OR 0.94, 95% CI 0.83 to 1.05).

AUTHORS' CONCLUSIONS

There is good evidence that statins given in late life to people at risk of vascular disease do not prevent cognitive decline or dementia. Biologically, it seems feasible that statins could prevent dementia due to their role in cholesterol reduction and initial evidence from observational studies was very promising. However, indication bias may have been a factor in these studies and the evidence from subsequent RCTs has been negative. There were limitations in the included studies involving the cognitive assessments used and the inclusion of participants at moderate to high vascular risk only.

Cognitive and Physical Function by Statin Exposure in Elderly Individuals Following Acute Myocardial Infarction

Despite beneficial effects on morbidity and mortality after acute myocardial infarction (AMI), concerns remain about the safety of statin therapy, particularly their potential effects on cognitive and physical function, in elderly individuals. Among statin-naive AMI patients age ≥ 65 years in a multicenter US registry, we examined the association between statin prescription at discharge and change in cognition (via Modified Telephone Interview for Cognitive Status [TICS-M]) assessed at 1 and 6 months after AMI. Short Form-12 Physical Component score, hand grip, walk time, and chair-rise tests were used to assess physical function. We conducted noninferiority testing to evaluate the hypothesis that the mean change in cognitive function was no worse among patients recently started on statins compared with those who were not. Among 317 elderly AMI patients, 262 patients (83%) were prescribed a statin at discharge and 55 were not. After matching for propensity to be discharged on statin after AMI, the effect of statin treatment on change in TICS-M from 1 to 6 months (estimated difference, 0.11 points; 95% confidence interval: -2.11 to 2.32, P = 0.92) showed noninferiority (inferiority threshold 3 points). There were no significant differences in any physical function measure. Among statin-naive elderly individuals recovering from AMI, initiation of statin therapy was not associated with detectable changes in short-term cognitive or physical function. These findings support the general safety of statin therapy for secondary prevention in this population.

Statins, cognition, and dementia—systematic review and methodological commentary

Firm conclusions about whether mid-life or long-term statin use has an impact on cognitive decline and dementia remain elusive. Here, our objective was to systematically review, synthesize and critique the epidemiological literature that examines the relationship between statin use and cognition, so as to assess the current state of knowledge, identify gaps in our understanding, and make recommendations for future research. We summarize the findings of randomized controlled trials (RCTs) and observational studies, grouped according to study design. We discuss the methods for each, and consider likely sources of bias, such as reverse causation and confounding. Although observational studies that considered statin use at or near the time of dementia diagnosis suggest a protective effect of statins, these findings could be attributable to reverse causation. RCTs and well-conducted observational studies of baseline statin use and subsequent cognition over several years of follow-up do not support a causal preventative effect of late-life statin use on cognitive decline or dementia. Given that much of the human research on statins and cognition in the future will be observational, careful study design and analysis will be essential.

Do statins impair cognition? A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

In 2012, the United States Food and Drug Administration (FDA) issued a warning regarding potential adverse effects of HMG-CoA reductase inhibitors (statins) on cognition, based on the Adverse Events Reporting System and a review of the medical literature. We aimed to synthesize randomized clinical trial (RCTs) evidence on the association between statin therapy and cognitive outcomes.

METHODS

We searched MEDLINE, EMBASE, and Cochrane CENTRAL through December 2012, and reviewed published systematic reviews of statin treatment. We sought RCTs that compared statin treatment versus placebo or standard care, and reported at least one cognitive outcome (frequency of adverse cognitive events or measurements using standard neuropsychological cognitive test scores). Studies reporting sufficient information to calculate effect sizes were included in meta-analyses. Standardized and unstandardized mean differences were calculated for continuous outcomes for global cognition and for pre-specified cognitive domains. The main outcome was change in cognition measured by neuropsychological tests; an outcome of secondary interest was the frequency of adverse cognitive events observed during follow-up.

RESULTS

We identified 25 RCTs (all placebo-controlled) reporting cognitive outcomes in 46,836 subjects, of which 23 RCTs reported cognitive test results in 29,012 participants. Adverse cognitive outcomes attributable to statins were rarely reported in trials involving cognitively normal or impaired subjects. Furthermore, meta-analysis of cognitive test data (14 studies; 27,643 participants) failed to show significant adverse effects of statins on all tests of cognition in either cognitively normal subjects (standardized mean difference 0.01, 95% confidence interval, CI, -0.01 to 0.03, p = 0.42) or Alzheimer's disease subjects (standardized mean difference -0.05, 95% CI -0.19 to 0.10, p = 0.38).

CONCLUSIONS

Statin therapy was not associated with cognitive impairment in RCTs. These results raise questions regarding the continued merit of the FDA warning about potential adverse effects of statins on cognition.

Neuropsychiatric adverse events associated with statins: epidemiology, pathophysiology, prevention and management

Statins, or 3-hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitors, such as lovastatin, atorvastatin, simvastatin, pravastatin, fluvastatin, rosuvastatin and pitavastatin, are cholesterol-lowering drugs used in clinical practice to prevent coronary heart disease. These drugs are generally well tolerated and have been rarely associated with severe adverse effects (e.g. rhabdomyolysis). Over the years, case series and data from national registries of spontaneous adverse drug reaction reports have demonstrated the occurrence of neuropsychiatric reactions associated with statin treatment. They include behavioural alterations (severe irritability, homicidal impulses, threats to others, road rage, depression and violence, paranoia, alienation, antisocial behaviour); cognitive and memory impairments; sleep disturbance (frequent awakenings, shorter sleep duration, early morning awakenings, nightmares, sleepwalking, night terrors); and sexual dysfunction (impotence and decreased libido). Studies designed to investigate specific neuropsychiatric endpoints have yielded conflicting results. Several mechanisms, mainly related to inhibition of cholesterol biosynthesis, have been proposed to explain the detrimental effects of statins on the central nervous system. Approaches to prevent and manage such adverse effects may include drug discontinuation and introduction of dietary restrictions; maintenance of statin treatment for some weeks with close patient monitoring; switching to a different statin; dose reduction; use of ω-3 fatty acids or coenzyme Q10 supplements; and treatment with psychotropic drugs. The available information suggests that neuropsychiatric effects associated with statins are rare events that likely occur in sensitive patients. Additional data are required, and further clinical studies are needed.

The Cache County Study on Memory in Aging: factors affecting risk of Alzheimer's disease and its progression after onset

The Cache County Study on Memory in Aging is a longitudinal, population-based study of Alzheimer's disease (AD) and other dementias. Initiated in 1995 and extending to 2013, the study has followed over 5,000 elderly residents of Cache County, Utah (USA) for over twelve years. Achieving a 90% participation rate at enrolment, and spawning two ancillary projects, the study has contributed to the literature on genetic, psychosocial and environmental risk factors for AD, late-life cognitive decline, and the clinical progression of dementia after its onset. This paper describes the major study contributions to the literature on AD and dementia.

Statins and cognition: a systematic review and meta-analysis of short- and long-term cognitive effects

OBJECTIVE

To evaluate the effect of statins on short-term cognitive function and the long-term incidence of dementia.

PATIENTS AND METHODS

A systematic search was performed of MEDLINE, EMBASE, and the Cochrane Central Register from their inception to April 25, 2013. Adults with no history of cognitive dysfunction treated with statins were included from high-quality randomized controlled trials and prospective cohort studies after formal bias assessment.

RESULTS

Sixteen studies were included in qualitative synthesis and 11 in quantitative synthesis. Short-term trials did not show a consistent effect of statin therapy on cognitive end points. Digit Symbol Substitution Testing (a well-validated measure of cognitive function) was the most common short-term end point, with no significant differences in the mean change from baseline to follow-up between the statin and placebo groups (mean change, 1.65; 95% CI, -0.03 to 3.32; 296 total exposures in 3 trials). Long-term cognition studies included 23,443 patients with a mean exposure duration of 3 to 24.9 years. Three studies found no association between statin use and incident dementia, and 5 found a favorable effect. Pooled results revealed a 29% reduction in incident dementia in statin-treated patients (hazard ratio, 0.71; 95% CI, 0.61-0.82).

CONCLUSION

In patients without baseline cognitive dysfunction, short-term data are most compatible with no adverse effect of statins on cognition, and long-term data may support a beneficial role for statins in the prevention of dementia.

Statins for the primary prevention of cardiovascular disease

BACKGROUND

Reducing high blood cholesterol, a risk factor for cardiovascular disease (CVD) events in people with and without a past history of CVD is an important goal of pharmacotherapy. Statins are the first-choice agents. Previous reviews of the effects of statins have highlighted their benefits in people with CVD. The case for primary prevention was uncertain when the last version of this review was published (2011) and in light of new data an update of this review is required.

OBJECTIVES

To assess the effects, both harms and benefits, of statins in people with no history of CVD.

SEARCH METHODS

To avoid duplication of effort, we checked reference lists of previous systematic reviews. The searches conducted in 2007 were updated in January 2012. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2022, Issue 4), MEDLINE OVID (1950 to December Week 4 2011) and EMBASE OVID (1980 to 2012 Week 1).There were no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials of statins versus placebo or usual care control with minimum treatment duration of one year and follow-up of six months, in adults with no restrictions on total, low density lipoprotein (LDL) or high density lipoprotein (HDL) cholesterol levels, and where 10% or less had a history of CVD.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion and extracted data. Outcomes included all-cause mortality, fatal and non-fatal CHD, CVD and stroke events, combined endpoints (fatal and non-fatal CHD, CVD and stroke events), revascularisation, change in total and LDL cholesterol concentrations, adverse events, quality of life and costs. Odds ratios (OR) and risk ratios (RR) were calculated for dichotomous data, and for continuous data, pooled mean differences (MD) (with 95% confidence intervals (CI)) were calculated. We contacted trial authors to obtain missing data.

MAIN RESULTS

The latest search found four new trials and updated follow-up data on three trials included in the original review. Eighteen randomised control trials (19 trial arms; 56,934 participants) were included. Fourteen trials recruited patients with specific conditions (raised lipids, diabetes, hypertension, microalbuminuria). All-cause mortality was reduced by statins (OR 0.86, 95% CI 0.79 to 0.94); as was combined fatal and non-fatal CVD RR 0.75 (95% CI 0.70 to 0.81), combined fatal and non-fatal CHD events RR 0.73 (95% CI 0.67 to 0.80) and combined fatal and non-fatal stroke (RR 0.78, 95% CI 0.68 to 0.89). Reduction of revascularisation rates (RR 0.62, 95% CI 0.54 to 0.72) was also seen. Total cholesterol and LDL cholesterol were reduced in all trials but there was evidence of heterogeneity of effects. There was no evidence of any serious harm caused by statin prescription. Evidence available to date showed that primary prevention with statins is likely to be cost-effective and may improve patient quality of life. Recent findings from the Cholesterol Treatment Trialists study using individual patient data meta-analysis indicate that these benefits are similar in people at lower (< 1% per year) risk of a major cardiovascular event.

AUTHORS' CONCLUSIONS

Reductions in all-cause mortality, major vascular events and revascularisations were found with no excess of adverse events among people without evidence of CVD treated with statins.

The effects of statins on prevention of stroke and dementia: a review

Stroke is the third leading cause of death in the United States and places a heavy toll on health care spending, especially in the elderly population. The prevalence of stroke increases with increasing age. Over the last 2 decades, there have been substantial data supporting the use of statins in the primary, as well as secondary, prevention of stroke. Although most of these studies were designed to evaluate cerebrovascular accidents (CVA) only as secondary endpoints, the data show a significant reduction in strokes associated with statin use. There have been numerous studies that have demonstrated the relationship between serum cholesterol levels, specifically low-density lipoprotein cholesterol, on CVA and the beneficial effects of statins in this setting. Furthermore, in addition to the lipid-lowering properties of statins, these drugs have also been shown to possess cholesterol-independent pleotropic properties that have been associated with neuroprotection. Finally, the role of statins for the prevention of dementia is still highly debatable. We examine the role of this class of drugs in the setting of dementia, particularly from vascular causes and stroke.

A review of the potential therapeutic role of statins in the treatment of Alzheimer's disease: current research and opinion

Alzheimer's disease is one of the most prevalent neurodegenerative disorders. However, there is no current treatment, which definitively influences disease progression over a sustained period. Numerous studies linking an increase in serum cholesterol, mainly during midlife, with the pathogenic process of Alzheimer's disease have been published. Therefore, the role of statins as a therapy in this disorder may be of great interest. The aim of the present review is to summarize of the role of statins in the treatment of Alzheimer's disease.

The controversies of statin therapy: weighing the evidence

The debate whether statins, 3-hydroxymethyl-3-methylglutaryl coenzyme A reductase inhibitors, are safe to use has been raging since their introduction in 1987. Statins are generally well tolerated and are believed to have minimal adverse effects. However, individual, specific rare adverse events have been reported, such as elevations of liver enzymes, muscle aches, and very rarely, rhabdomyolysis. Discontinuation and/or reduction in the dose of the statin usually leads to resolution of these side effects. Recently, however, debate has focused on the possible negative long-term effects of statin treatment on cognitive decline, the incidence of cancer, and the development of diabetes mellitus. Recently, the U.S. Food and Drug Administration has expanded the warning for statins with a statement that statin use may lead to cognitive impairment. In this review, we discuss all levels of evidence, from case reports to large randomized controlled clinical trials, for the possible adverse effects of statins on cognitive decline, cancer, and diabetes. After careful consideration of all discussed scientific evidence, we conclude that there is no increased risk of cognitive decline or cancer with statin use. However, statin use is related to a small increased risk of type 2 diabetes mellitus. In view of the overwhelming benefit of statins in the reduction of cardiovascular events, we believe the small absolute risk for development of diabetes is outweighed by the cardiovascular benefits in patients for whom statin therapy is recommended. We, therefore, suggest that clinical practice for statin therapy should not be changed on the basis of the most recent Food and Drug Administration informational warnings.

Is statin-associated cognitive impairment clinically relevant? A narrative review and clinical recommendations

OBJECTIVE

To explore the impact of statin use on cognition.

DATA SOURCES

A literature search was performed using MEDLINE (1950-November 2011), EMBASE (1980-November 2011), and the Cochrane Library (1960-November 2011) using the search terms "cognition/drug effects," "delirium, dementia, amnestic, cognitive disorders/chemically induced," "memory disorders/chemically induced," "hydroxymethylglutaryl-CoA reductase inhibitors/adverse effects," and "hydroxymethylglutaryl-CoA reductase inhibitors." A bibliographic search on included references was also conducted.

STUDY SELECTION AND DATA EXTRACTION

Studies were included for analysis if they were conducted in humans and examined the impact of statin use on cognition as either a primary or secondary endpoint; case reports and case series were also included for analysis.

DATA SYNTHESIS

Reports of statin-associated cognitive impairment were found primarily in observational studies (eg, case reports/series). One randomized controlled trial demonstrated that simvastatin impaired some measures of cognition compared to placebo. Conversely, in the majority of randomized controlled trials and observational studies, statins were found to have either a neutral or beneficial effect on cognition. Preliminary data suggest that statins that are less lipophilic (ie, pravastatin and rosuvastatin) may be less likely to contribute to cognitive impairment due to limited penetration across the blood-brain barrier. These drugs would be a logical alternative in cases where cognitive impairment secondary to another statin is suspected.

CONCLUSIONS

Despite several reports of statin-associated cognitive impairment, this adverse effect remains a rare occurrence among the totality of the literature. If statin-associated cognitive impairment is suspected, a trial discontinuation can reveal a temporal relationship. Switching from lipophilic to hydrophilic statins may resolve cognitive impairment. The vascular benefits and putative cognitive benefits outweigh the risk of cognitive impairment associated with statin use; therefore, the current evidence does not support changing practice with respect to statin use, given this adverse effect.

Statins for the primary prevention of cardiovascular disease

BACKGROUND

Reducing high blood cholesterol, a risk factor for cardiovascular disease (CVD) events in people with and without a past history of coronary heart disease (CHD) is an important goal of pharmacotherapy. Statins are the first-choice agents. Previous reviews of the effects of statins have highlighted their benefits in people with coronary artery disease. The case for primary prevention, however, is less clear.

OBJECTIVES

To assess the effects, both harms and benefits, of statins in people with no history of CVD.

SEARCH STRATEGY

To avoid duplication of effort, we checked reference lists of previous systematic reviews. We searched the Cochrane Central Register of Controlled Trials (Issue 1, 2007), MEDLINE (2001 to March 2007) and EMBASE (2003 to March 2007). There were no language restrictions.

SELECTION CRITERIA

Randomised controlled trials of statins with minimum duration of one year and follow-up of six months, in adults with no restrictions on their total low density lipoprotein (LDL) or high density lipoprotein (HDL) cholesterol levels, and where 10% or less had a history of CVD, were included.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion and extracted data. Outcomes included all cause mortality, fatal and non-fatal CHD, CVD and stroke events, combined endpoints (fatal and non-fatal CHD, CVD and stroke events), change in blood total cholesterol concentration, revascularisation, adverse events, quality of life and costs. Relative risk (RR) was calculated for dichotomous data, and for continuous data pooled weighted mean differences (with 95% confidence intervals) were calculated.

MAIN RESULTS

Fourteen randomised control trials (16 trial arms; 34,272 participants) were included. Eleven trials recruited patients with specific conditions (raised lipids, diabetes, hypertension, microalbuminuria). All-cause mortality was reduced by statins (RR 0.83, 95% CI 0.73 to 0.95) as was combined fatal and non-fatal CVD endpoints (RR 0.70, 95% CI 0.61 to 0.79). Benefits were also seen in the reduction of revascularisation rates (RR 0.66, 95% CI 0.53 to 0.83). Total cholesterol and LDL cholesterol were reduced in all trials but there was evidence of heterogeneity of effects. There was no clear evidence of any significant harm caused by statin prescription or of effects on patient quality of life.

AUTHORS' CONCLUSIONS

Although reductions in all-cause mortality, composite endpoints and revascularisations were found with no excess of adverse events, there was evidence of selective reporting of outcomes, failure to report adverse events and inclusion of people with cardiovascular disease. Only limited evidence showed that primary prevention with statins may be cost effective and improve patient quality of life. Caution should be taken in prescribing statins for primary prevention among people at low cardiovascular risk.

Greasing the wheels of Abeta clearance in Alzheimer's disease: the role of lipids and apolipoprotein E

Although apolipoprotein E (apoE) is the most common genetic risk factor for Alzheimer's Disease (AD), how apoE participates in AD pathogenesis remains incompletely understood. ApoE is also the major carrier of lipids in the brain. Here, we review studies showing that the lipidation status of apoE influences the metabolism of Abeta peptides, which accumulate as amyloid deposits in the neural parenchyma and cerebrovasculature. One effect of apoE is to inhibit the transport of Abeta across the blood-brain-barrier (BBB), particularly when apoE is lipidated. A second effect is to facilitate the proteolytic degradation of Abeta by neprilysin and insulin degrading enzyme (IDE), which is enhanced when apoE is lipidated. We also describe how apoE becomes lipidated and how this impacts Abeta metabolism. Specifically, genetic loss of the cholesterol transporter ABCA1 impairs apoE lipidation and promotes amyloid deposition in AD mouse models. ABCA1 catalyses the ATP-dependent transport of cholesterol and phospholipids from the plasma membrane to lipid-free apolipoproteins including apoE. Conversely, selective overexpression of ABCA1 increases apoE lipidation in the central nervous system (CNS) and eliminates the formation of amyloid plaques in vivo. Deficiency of Liver-X-Receptors (LXRs), transcription factors that stimulate ABCA1 and apoE expression, exacerbates AD pathogenesis in vivo, whereas treatment of AD mice with synthetic LXR agonists reduces amyloid load and improves cognitive performance. These studies provide new insights into the mechanisms by which apoE affects Abeta metabolism, and offer opportunities to develop novel therapeutic approaches to reduce the leading cause of dementia in the elderly.

Statins for the prevention of dementia

BACKGROUND

This is an update of a Cochrane review first published in 2001. At that stage there was insufficient evidence to recommend statins for the prevention of Alzheimer's disease (AD). The scope of this review has been expanded to include all forms of dementia.

OBJECTIVES

To assess the effects of statins in the prevention of dementia.

SEARCH STRATEGY

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group, The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS were searched on 10 October 2007 using the terms statin*, lovastatin*, pravastatin*, simvastatin*, fluvastatin*, atorvastatin* and rosuvastatin*. The CDCIG Register contains records from many healthcare databases, SIGLE, LILACS as well as many trials databases and is updated regularly.

SELECTION CRITERIA

Double-blind randomized placebo-controlled trials of statins in people at risk of AD and dementia.

DATA COLLECTION AND ANALYSIS

Two independent reviewers extracted and assessed data independently and agreement was reached after discussion. Adverse effects were noted.

MAIN RESULTS

Two trials were identified with 26,340 participants; HPS 2002 and PROSPER 2002. Age range was 40-82 years across the two studies, PROSPER 2002 included 5804 patients aged 70-82 years and HPS included 20,536 patients with 5806 at least 70 years old at study entry. Mean total cholesterol 5.9 mmol/l, LDL cholesterol 3.4 mmol/l at study entry with mean reduction in LDL cholesterol of 1.0 mmol/l in simvastatin treated patients compared to placebo in HPS 2002. Mean total cholesterol 5.7 mmol/l, LDL cholesterol 3.8 mmol/l at study entry with mean reduction in LDL cholesterol of 1.02 mmol/l in pravastatin treated patients compared to placebo in PROSPER 2002. Mean follow-up 3.2 years in PROSPER, 5 years in HPS 2002. Cognition was measured at different times and with different scales so could not be combined in a meta-analysis. There was no difference in incidence of dementia in HPS 2002 (31 cases in simvastatin group, 31 cases in placebo group) nor in performance on the modified Telephone Interview for Cognitive Status at final follow-up (23.7% simvastatin group cognitively impaired vs 24.2% in placebo group). There was no difference in cognition between groups either in relation to age at study entry or previous history of cerebrovascular disease. Cognitive function declined at the same rate in both treatment groups in PROSPER 2002, there was no significant difference between pravastatin treated and placebo groups in performance on letter digit codes, picture word learning test, Stroop and Mini Mental State Examination. There was no evidence that statins were detrimental to cognition.

AUTHORS' CONCLUSIONS

There is good evidence from RCTs that statins given in late life to individuals at risk of vascular disease have no effect in preventing AD or dementia. Biologically it seems feasible that statins could prevent dementia due to their role in cholesterol reduction and initial evidence from observational studies was very promising. Indication bias may have been a factor in these studies however and the evidence from subsequent RCTs has been negative.

Statins: mechanisms of neuroprotection

Clinical trials report that the class of drugs known as statins may be neuroprotective in Alzheimer's and Parkinson's disease, and further trials are currently underway to test whether these drugs are also beneficial in multiple sclerosis and acute stroke treatment. Since statins are well tolerated and have relatively few side effects, they may be considered as viable drugs to ameliorate neurodegenerative diseases. However, the mechanism of their neuroprotective effects is only partly understood. In this article, we review the current data on the neuroprotective effects of statins and their underlying mechanisms. In the first section, we detail the mechanisms by which statins affect cellular signalling. The primary action of statins is to inhibit cellular cholesterol synthesis. However, the cholesterol synthesis pathway also has several by-products, the non-sterol isoprenoids that are also important in cellular functioning. Furthermore, reduced cholesterol levels may deplete the cholesterol-rich membrane domains known as lipid rafts, which in turn could affect cellular signalling. In the second section, we summarize how the effects on signalling translate into general neuroprotective effects through peripheral systems. Statins improve blood-flow, reduce coagulation, modulate the immune system and reduce oxidative damage. The final section deals with the effects of statins on the central nervous system, particularly during Alzheimer's and Parkinson's disease, stroke and multiple sclerosis.

Identifying health-related quality of life (HRQL) domains for multiple chronic conditions (diabetes, hypertension and dyslipidemia): patient and provider perspectives

OBJECTIVE

To examine patient and provider perspectives about the impact of having diabetes, hypertension and/or dyslipidemia (DHD) on health-related quality of life (HRQL) in order to identify domains for an HRQL instrument focusing on specific chronic diseases (DHD).

STUDY DESIGN

Exploratory qualitative design was used to elicit patient and provider responses. Patient survey contained 11 demographic and nine content questions inquiring how the disease(s) affected patient HRQL. Provider survey examined how the disease(s) affected their patient's HRQL and crucial factors for improvement. Patients were included if they had DHD and spoke English. Providers working with DHD patients were identified among university faculty and community practitioners.

RESULTS

Thirty-eight patients (24.7%) completed the interviews. Three judges content analysed patient responses and proposed seven categories (patients ranked physical functioning first followed by diet, emotional well-being (E), general well-being, social functioning (S), 'no change in HRQL' and medications). One question about medications had four categories (medication inconvenience, medication side effects, forgetfulness and general well-being). Index for reliability was greater than 80% for all categories. Providers ranked lifestyle modification (LM), first followed by complications, medication, self-care, E, education, S, physical activity and resources (ability to pay) as components that impact HRQL.

CONCLUSIONS

Patient and provider perspectives were similar in four areas (E, S, medication and diet); however, the differences were in how these impacted HRQL - patients focused on activities relevant to daily life that were affected, while providers based it on processes of therapy management and self-care (education and implementation of LM).

Prevention of Alzheimer's disease

The already considerable public health burden of Alzheimer's disease will likely worsen as populations around the world age. As a result, there is considerable motivation to develop effective strategies for preventing the disease. A wide variety of such strategies are under investigation and include pharmaceuticals, nutriceuticals, diet, physical activity and cognitive activity. We review here the most promising candidates and the epidemiologic evidence for their efficacy. Although none of these have yet to be definitively shown to prevent Alzheimer's disease, further research should help to clarify what role they may play in reducing the burden of this disease.

Effect of Atorvastatin on Cognitive Function in Patients from the Lipid Lowering and Onset of Renal Disease (LORD) Trial

STUDY OBJECTIVE

To examine the effect of atorvastatin on cognitive function by testing two hypotheses: that atorvastatin 10 mg/day would impair cognitive function, and that other biochemical and demographic measures would better predict cognitive performance than atorvastatin alone.

DESIGN

Randomized, double-blind, placebo-controlled study.

SETTING

Two primary acute care settings in the north and northwest of Tasmania, Australia.

PATIENTS

Fifty-seven patients from the Lipid Lowering and Onset of Renal Disease (LORD) trial.

INTERVENTION

Participants were randomly assigned to receive either atorvastatin 10 mg/day or matching placebo. Cognitive testing was performed in two sessions occurring 12 weeks apart and involved three repeated measures of attention and concentration.

MEASUREMENTS AND MAIN RESULTS

Performance was measured using three standard neuropsychological tests: Digit Symbol Coding subtest, Trail Making Test, and Stroop Color-Word Reading Test. Patients received atorvastatin for a mean of 72.93 weeks and placebo for a mean of 68.85 weeks. Repeated-measures multivariate analysis of variance failed to identify any significant differences between the two groups on any of the three cognitive measures. Multiple regression analyses identified no single factor or combination of plasma cholesterol levels, renal function, liver function, or age that predicted cognitive performance in either the atorvastatin or placebo group on the three measures at either testing session.

CONCLUSION

Atorvastatin 10 mg/day did not produce decrements to cognitive performance. In addition, biochemical and demographic measures and the receipt of atorvastatin versus placebo did not individually or in combination predict cognitive performance on measures of attention and concentration.

Systematic review and meta-analysis of clinically relevant adverse events from HMG CoA reductase inhibitor trials worldwide from 1982 to present

PURPOSE

Our objective was to determine the association of clinically relevant adverse events from a systematic review and meta-analysis of statin randomized controlled trials (RCT).

METHODS

We performed the meta-analysis in the manner of a Cochrane Collaboration systematic review. Outcomes were discontinuances of therapy or muscle-related symptoms due to adverse events. We searched for articles from 1982 through June 2006 in MEDLINE and other databases. The main inclusion criteria were double blind, placebo controlled RCTs with a monotherapy intervention of any marketed statin and active surveillance of adverse events. We excluded studies of drug interactions, organ transplants, or exercise, or those not meeting all of the study quality criteria. The primary analysis was a statin formulation stratified fixed-effect model using Peto odds-ratios (POR). Secondary analyses explored the stability of the primary results.

RESULTS

Over 86,000 study participants from 119 studies were included. Available statins were associated with a lower POR of discontinuance (overall: 0.88 [0.84, 0.93], largest effect with pravastatin: 0.79 [0.74, 0.84]), an elevated POR of rhabdomyolysis (1.59 [0.54, 4.70]) and myositis (2.56 [1.12, 5.85]), and null odds of myalgia (1.09 [0.97, 1.23]). Cerivastatin by comparison demonstrated larger PORs for discontinuances and muscle-related adverse events. Secondary analyses demonstrated the stability of the results.

CONCLUSIONS

Overall, discontinuation of statin therapy due to adverse events was no worse than placebo. The risks of muscle-related adverse events were in general agreement with the known risks of statins.