Role of statins in Alzheimer's disease: a retrospective meta-analysis for commonly investigated clinical parameters in RCTs

Aggressive LDL-C Lowering and the Brain: Impact on Risk for Dementia and Hemorrhagic Stroke: A Scientific Statement From the American Heart Association

The objective of this scientific statement is to evaluate contemporary evidence that either supports or refutes the conclusion that aggressive low-density lipoprotein cholesterol lowering or lipid lowering exerts toxic effects on the brain, leading to cognitive impairment or dementia or hemorrhagic stroke. The writing group used literature reviews, references to published clinical and epidemiology studies, clinical and public health guidelines, authoritative statements, and expert opinion to summarize existing evidence and to identify gaps in current knowledge. Although some retrospective, case control, and prospective longitudinal studies suggest that statins and low-density lipoprotein cholesterol lowering are associated with cognitive impairment or dementia, the preponderance of observational studies and data from randomized trials do not support this conclusion. The risk of a hemorrhagic stroke associated with statin therapy in patients without a history of cerebrovascular disease is nonsignificant, and achieving very low levels of low-density lipoprotein cholesterol does not increase that risk. Data reflecting the risk of hemorrhagic stroke with lipid-lowering treatment among patients with a history of hemorrhagic stroke are not robust and require additional focused study.

Dementia risk reduction: why haven't the pharmacological risk reduction trials worked? An in-depth exploration of seven established risk factors

Identifying the leading health and lifestyle factors for the risk of incident dementia and Alzheimer's disease has yet to translate to risk reduction. To understand why, we examined the discrepancies between observational and clinical trial evidence for seven modifiable risk factors: type 2 diabetes, dyslipidemia, hypertension, estrogens, inflammation, omega-3 fatty acids, and hyperhomocysteinemia. Sample heterogeneity and paucity of intervention details (dose, timing, formulation) were common themes. Epidemiological evidence is more mature for some interventions (eg, non-steroidal anti-inflammatory drugs [NSAIDs]) than others. Trial data are promising for anti-hypertensives and B vitamin supplementation. Taken together, these risk factors highlight a future need for more targeted sample selection in clinical trials, a better understanding of interventions, and deeper analysis of existing data.

The efficacy of statins in the treatment of Alzheimer's disease: a meta-analysis of randomized controlled trial

OBJECTIVE

Alzheimer's disease (AD) is a common type of dementia, which has caused heavy global economic and health burden, and the using of statins to treat AD has caused widely debated. The purpose of this meta-analysis is to explore the effect of statins in the treatment of Alzheimer's disease.

METHODS

Studies were retrieved by searching PubMed, Embase, Cochrane library, OvisdSP, Web of Science, Chinese Nation Knowledge Infrastructure (CNKI) and Chinese Biomedical Database (CBM) databases before March 31, 2019. We extracted the Mini-Mental State Examination (MMSE), Alzheimer's Disease Assessment Scale-cognitive (ADAS-Cog), Neuropsychiatric Inventory (NPI), Activities of Daily Living (ADL) scale score, and other information. The pooled Weighted Mean Difference (WMD) and their 95% confidence intervals (95% CI) were calculated with random effect model or fixed random effect model.

RESULTS

A total of nine randomized controlled trials were included that contained 1489 patients; of them, 742 patients in the statins group, 747 patients in the control group. There were nine studies used the MMSE scale, five studies used the ADAS-Cog scale, four studies used the NPI scale, and six studies used the ADL scale. Meta-analysis of the nine studies that reported the MMSE scale scores indicated that there is no significant effect of statins as compared with control group (the pooled WMD = 1.09, 95% CI, - 0.00, 2.18, p = 0.05, I² = 87.9%). Meta-analysis of the five studies that reported the ADAS-Cog scale scores also indicated that there is no significant effect of statins as compared with control group (the pooled WMD = - 0.16, 95% CI, - 2.67, 2.36, p = 0.90, I² = 80.1%). Meta-analysis of the four studies that reported the NPI scale scores indicated that treatment with statins could slow the rise in the NPI scale scores (the pooled WMD = - 1.16, 95% CI, - 1.88, - 0.44, p = 0.002, I² = 45.4%). Meta-analysis of the six studies that reported the ADL scale scores indicated that treatment with statins could improve patients' daily living ability (the pooled WMD = - 4.06, 95% CI, - 6.88, - 1.24, p = 0.005, I² = 86.7%). Results of subgroup analysis indicated that the use of statins in the short term (≤ 12 months) associated with the change of the MMSE scale scores (the pooled WMD = 1.78, 95% CI, 0.53, 3.04, p = 0.005, I² = 79.6%). Sensitivity analysis and publication bias test were both negative, and the results were relatively reliable and stable.

CONCLUSION

Statins used in AD patients had beneficial effects on the scores of MMSE scale in the short term (≤ 12 months), and statins could slow the deterioration of neuropsychiatric status and significantly improve activities of daily living ability in AD patients, but statins did not show an advantage in the change of the ADAS-Cog scale scores.

Systematic review of the efficacy of statins for the treatment of Alzheimer's disease

Alzheimer's disease (AD) is the most common type of dementia. Recent studies have assessed the possibility of using statins as treatment for AD. However, their efficacy is not clear. In this study, we collected the most relevant information about the efficacy of statins for the treatment of AD. We conducted a systematic literature search using MEDLINE, EMBASE and The Cochrane Library. We included clinical trials, meta-analyses and systematic reviews that analysed the efficacy of statins in AD. We also extracted the characteristics and efficacy results of the studies selected. Of the 304 articles identified, 13 complied with the inclusion criteria. The scientific quality of studies was high and their results indicated that there were no significant differences in the main efficacy variables between statins and placebo treatment for AD. Therefore, according to the available scientific evidence, statins have not shown an improvement in cognition and do not appear to offer significant benefits to patients with AD.

Pharmacogenetic considerations in the treatment of Alzheimer's disease

The practical pharmacogenetics of Alzheimer's disease (AD) is circumscribed to acetylcholinesterase inhibitors (AChEIs) and memantine. However, pharmacogenetic procedures should be applied to novel strategies in AD therapeutics including: novel AChEIs and neurotransmitter regulators, anti-Aβ treatments, anti-tau treatments, pleiotropic products, epigenetic drugs and combination therapies. Genes involved in the pharmacogenetic network are under the influence of the epigenetic machinery which regulates gene expression transcriptionally and post-transcriptionally, configuring the fundamentals of pharmacoepigenomics. Over 60% of AD patients present concomitant pathologies demanding additional treatments which increase the likelihood of drug-drug interactions. Lipid metabolism dysfunction is a pathogenic mechanism inherent to AD neurodegeneration. The therapeutic response to hypolipidemic compounds is influenced by the APOE and CYP genotypes. The development of novel compounds and the use of combination/multifactorial treatments require the implantation of pharmacogenomic procedures for the avoidance of ADRs and the optimization of therapeutics.

[Statins Use in Elderly Patients]

The risk of cardiovascular disease in elderly is significantly higher than in young subjects; paradoxically some treatments that have proven their efficacy in reducing cardiovascular risk are often under prescribed in this age group. The benefits of statins in secondary cardiovascular prevention are well established in patients <80 years. In primary prevention, these drugs reduce the risk of myocardial infarction and stroke, but their effects on cardiovascular mortality remain uncertain. In very elderly patients, there are no randomized trials relative to the impact of statins on morbi-mortality in primary prevention as well in secondary prevention. Adverse effects in the elderly seem to be statistically similar to those occurring in young people , but the prescription in very old people should be individualized, taking into account the life expectancy, the life quality, the comorbidities, and especially the risk of drug interactions.

Statins for the treatment of dementia

BACKGROUND

The use of statin therapy in established Alzheimer's disease (AD) or vascular dementia (VaD) is a relatively unexplored area. In AD, β-amyloid protein (Aβ) is deposited in the form of extracellular plaques and previous studies have determined Aβ generation is cholesterol dependent. Hypercholesterolaemia has also been implicated in the pathogenesis of VaD. Due to the role of statins in cholesterol reduction, it is biologically plausible they may be efficacious in the treatment of AD and VaD.

OBJECTIVES

To assess the clinical efficacy and safety of statins in the treatment of AD and VaD. To evaluate if the efficacy of statins in the treatment of AD and VaD depends on cholesterol level, 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 and LILACS, as well as many trials registries and grey literature sources (20 January 2014).

SELECTION CRITERIA

Double-blind, randomised controlled trials of statins given for at least six months in people with a diagnosis of dementia.

DATA COLLECTION AND ANALYSIS

Two independent authors extracted and assessed data against the inclusion criteria. We pooled data where appropriate and entered them into a meta-analysis. We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We identified four studies (1154 participants, age range 50 to 90 years). All participants had a diagnosis of probable or possible AD according to standard criteria and most participants were established on a cholinesterase inhibitor. The primary outcome in all studies was change in Alzheimer's Disease Assessment Scale - cognitive subscale (ADAS-Cog) from baseline. When we pooled data, there was no significant benefit from statin (mean difference -0.26, 95% confidence interval (CI) -1.05 to 0.52, P value = 0.51). All studies provided change in Mini Mental State Examination (MMSE) from baseline. There was no significant benefit from statins in MMSE when we pooled the data (mean difference -0.32, 95% CI -0.71 to 0.06, P value = 0.10). Three studies reported treatment-related adverse effects. When we pooled data, there was no significant difference between statins and placebo (odds ratio 1.09, 95% CI 0.58 to 2.06, P value = 0.78). There was no significant difference in behaviour, global function or activities of daily living in the statin and placebo groups. We assessed risk of bias as low for all studies. We found no studies assessing role of statins in treatment of VaD.

AUTHORS' CONCLUSIONS

Analyses from the studies available, including two large randomised controlled trials, indicate that statins have no benefit on the primary outcome measures of ADAS-Cog or MMSE.

Treatment of dyslipidemia and cardiovascular outcomes: the journey so far--is this the end for statins?

Dyslipidemia is common and is associated with the highest population-attributable risk for cardiovascular disease. Of various cardiovascular preventive therapies, the evidence from randomized controlled trials supporting the importance of aggressive lipid lowering is the most robust, particularly for statins. Despite the use of proven therapies, cardiovascular disease event rates remain relatively high, underpinning the development of novel therapies. In addition to testing new drugs to reduce low-density-lipoprotein cholesterol, there has been a major focus on treatments that can favorably influence high-density-lipoprotein cholesterol and triglyceride levels. This review provides an overview of the important relationship between lipids and cardiovascular disease, the lipid-modifying therapeutic approaches to reducing cardiovascular disease, new guidelines and recommendations, and the challenges ahead for the treatment of dyslipidemia, particularly whether statins will remain at the forefront of recommended therapies.

Pharmacogenomics of Alzheimer's disease: novel therapeutic strategies for drug development

Alzheimer's disease (AD) is a major problem of health and disability, with a relevant economic impact on our society. Despite important advances in pathogenesis, diagnosis, and treatment, its primary causes still remain elusive, accurate biomarkers are not well characterized, and the available pharmacological treatments are not cost-effective. As a complex disorder, AD is a polygenic and multifactorial clinical entity in which hundreds of defective genes distributed across the human genome may contribute to its pathogenesis. Diverse environmental factors, cerebrovascular dysfunction, and epigenetic phenomena, together with structural and functional genomic dysfunctions, lead to amyloid deposition, neurofibrillary tangle formation, and premature neuronal death, the major neuropathological hallmarks of AD. Future perspectives for the global management of AD predict that genomics and proteomics may help in the search for reliable biomarkers. In practical terms, the therapeutic response to conventional drugs (cholinesterase inhibitors, multifactorial strategies) is genotype-specific. Genomic factors potentially involved in AD pharmacogenomics include at least five categories of gene clusters: (1) genes associated with disease pathogenesis; (2) genes associated with the mechanism of action of drugs; (3) genes associated with drug metabolism (phase I and II reactions); (4) genes associated with drug transporters; and (5) pleiotropic genes involved in multifaceted cascades and metabolic reactions. The implementation of pharmacogenomic strategies will contribute to optimize drug development and therapeutics in AD and related disorders.

Diagnosis, prevention, and management of statin adverse effects and intolerance: Canadian Working Group Consensus update

The Proceedings of a Canadian Working Group Consensus Conference, first published in 2011, provided a summary of statin-associated adverse effects and intolerance and management suggestions. In this update, new clinical studies identified since then that provide further insight into effects on muscle, cognition, cataracts, diabetes, kidney disease, and cancer are discussed. Of these, the arenas of greatest controversy pertain to purported effects on cognition and the emergence of diabetes during long-term therapy. Regarding cognition, the available evidence is not strongly supportive of a major adverse effect of statins. In contrast, the linkage between statin therapy and incident diabetes is more firm. However, this risk is more strongly associated with traditional risk factors for new-onset diabetes than with statin itself and any possible negative effect of new-onset diabetes during statin treatment is far outweighed by the cardiovascular risk reduction benefits. Additional studies are also discussed, which support the principle that systematic statin rechallenge, and lower or intermittent statin dosing strategies are the main methods for dealing with suspected statin intolerance at this time.