Statin use reduces the risk of dementia in elderly patients: a nationwide data survey and propensity analysis

Statin Initiation and Risk of Incident Alzheimer Disease and Cognitive Decline in Genetically Susceptible Older Adults

BACKGROUND AND OBJECTIVES

The association of statin initiation with incident Alzheimer disease (AD) dementia and cognitive decline by the APOE ε4 allele is unknown. Our objective was to examine whether the association of statin initiation with incident AD dementia and cognitive decline differs by the APOE ε4 allele.

METHODS

This population-based longitudinal cohort study was conducted in 4 urban communities in Chicago, IL, United States, consisting of 4,807 participants. Statin initiation is based on the inspection of medications during home assessments. Clinical diagnosis for incident AD used the NINCDS-ADRDA criteria, and longitudinal measurements of global cognition consisted of episodic memory, perceptual speed, and the Mini-Mental State Examination tests.

RESULTS

The study participants had a mean age of 72 years, consisting of 63% female individuals and 61% non-Hispanic Black individuals. During the study period, 1,470 (31%) participants reported statin initiation. In a covariate-adjusted competing risk model, statin initiation was associated with a reduced risk of incident clinical AD [hazard ratio (HR) 0.81 (95% CI 0.70-0.94)] compared with nonusers. This association was statistically significantly lower (p interaction = 0.015) among participants with the APOE ε4 allele [HR 0.60 (95% CI 0.49-0.74)] compared with those without the APOE ε4 allele [HR 0.96 (95% CI 0.82-1.12)]. The annual decline in global cognition (β = 0.021, 95% CI 0.007-0.034) and episodic memory (β = 0.020, 95% CI 0.007-0.033) was also substantially slower among participants with the APOE ε4 allele after statin initiation compared with nonusers. However, the association of statin initiation with cognitive decline was not significant among those without the APOE ε4 allele.

DISCUSSION

Our findings suggest that statins might be associated with a lower risk of incident AD among individuals with the APOE ε4 allele. The benefits of statin therapy need further consideration in randomized clinical trials, especially among those with the APOE ε4 allele.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that among those aged 65 years or older, statin initiation was associated with a reduced risk of Alzheimer disease, especially in the presence of an APOE-e4 allele.

Benzodiazepine use and the risk of dementia

Introduction

Benzodiazepines (BZDs) are commonly prescribed for anxiety and agitations, which are early symptoms of Alzheimer's disease and related dementias (ADRD). It is unclear whether BZDs causally affect ADRD risk or are prescribed in response to early symptoms of dementia.

Methods

We replicate prior case-control studies using longitudinal Medicare claims. To mitigate bias from prodromal use, we compare rates of ADRD diagnosis for beneficiaries exposed and unexposed to BZDs for cervical/lumbar pain, stenosis, and sciatica, none of which are associated with dementia.

Results

Approximately 8% of Medicare beneficiaries used a BZD in 2007, increasing to nearly 13% by 2013. Estimates from case-control designs are sensitive to duration of look-back period, health histories, medication use, and exclusion of decedents. Incident BZD use is not associated with an increased risk of dementia in an "uncontaminated" sample of beneficiaries prescribed a BZD for pain (odds ratios (ORs) of 1.007 [95% confidence interval [CI] = 0.885, 1.146] and 0.986 [95% CI = 0.877, 1.108], respectively, in the 2013 and 2013 to 2015 pooled samples). Higher levels of BZD exposure (>365 days over a 2-year period) are associated with increased odds of a dementia diagnosis, but the results are not statistically significant at the 5% or 10% levels (1.190 [95% CI = 0.925, 1.531] and 1.167 [95% CI = 0.919, 1.483]).

Discussion

We find little evidence of a causal relation between BZD use and dementia risk. Nonetheless, providers should limit the extended use in elderly populations.

The Efficacy and Safety of Alzheimer's Disease Therapies: An Updated Umbrella Review

BACKGROUND

Evidence summaries for efficacy and safety of frequently employed treatments of Alzheimer's disease (AD) are sparse.

OBJECTIVE

We aimed to perform an updated umbrella review to identify an efficacious and safe treatment for AD patients.

METHODS

We conducted a search for meta-analyses and systematic reviews on the Embase, PubMed, The Cochrane Library, and Web of Science to address this knowledge gap. We examined the cognitive functions, behavioral symptoms, global clinical assessment, and Activities of Daily Living as efficacy endpoints, and the incidence of adverse events as safety profiles.

RESULTS

Sixteen eligible papers including 149 studies were included in the umbrella review. The results showed that AChE inhibitors (donepezil, galantamine, rivastigmine, Huperzine A), Ginkgo biloba, and cerebrolysin appear to be beneficial for cognitive, global performances, and activities of daily living in patients with AD. Furthermore, anti-Aβ agents are unlikely to have an important effect on slowing cognitive or functional impairment in mild to moderate AD.

CONCLUSION

Our study demonstrated that AChE inhibitors, Ginkgo biloba, and cerebrolysin are the optimum cognitive and activities of daily living medication for patients with AD.

Statin use and risk of dementia or Alzheimer's disease: a systematic review and meta-analysis of observational studies

AIMS

As the potential impact of statins on cognitive decline and dementia is still debated, we conducted a meta-analysis of observational studies to examine the effect of statin use on the risk of Alzheimer's disease (AD) and dementia.

METHODS AND RESULTS

PubMed, Cochrane, and EMBASE were searched since inception to January 2021. Inclusion criteria were: (i) cohort or case-control studies; (ii) statin users compared to non-users; and (iii) AD and/or dementia risk as outcome. Estimates from original studies were pooled using restricted maximum-likelihood random-effect model. Measure of effects were reported as odds ratio (OR) and 95% confidence intervals (CIs). In the pooled analyses, statins were associated with a decreased risk of dementia [36 studies, OR 0.80 (CI 0.75-0.86)] and of AD [21 studies, OR 0.68 (CI 0.56-0.81)]. In the stratified analysis by sex, no difference was observed in the risk reduction of dementia between men [OR 0.86 (CI 0.81-0.92)] and women [OR 0.86 (CI 0.81-0.92)]. Similar risks were observed for lipophilic and hydrophilic statins for both dementia and AD, while high-potency statins showed a 20% reduction of dementia risk compared with a 16% risk reduction associated with low-potency statins, suggesting a greater efficacy of the former, although a borderline statistical significance (P = 0.05) for the heterogeneity between estimates.

CONCLUSION

These results confirm the absence of a neurocognitive risk associated with statin treatment and suggest a potential favourable role of statins. Randomized clinical trials with an ad hoc design are needed to explore this potential neuroprotective effect.

Association between statin use and cognitive function: A systematic review of randomized clinical trials and observational studies

The US Food and Drug Administration issued a black box warning in 2012 regarding the association of statin use with cognitive impairment. This may deter patients and practitioners from using statins for guideline-directed indications. Large studies have not shown an increase in cognitive impairment with statin use. MEDLINE, EMBASE, and Cochrane databases were searched up to October 2019. We present an up-to-date systematic review of randomized controlled trials (RCTs) and prospective observational studies examining the association between statin use and cognitive status in a population aged ≥60 years. Twenty-four studies with 1,404,459 participants were included in the review. Twenty-one were prospective observational studies, and 3 were RCTs. All 3 RCTs, which ranged from 3.2 to 5.6 years of follow-up, showed no significant association between statin use and adverse cognitive effects (odds ratio [OR] 1.03 [0.82-1.30]) and (OR 1.0 [0.61-1.65]). The mean difference in the Mini-Mental State Examination was insignificant (0.06 [-0.04 to 0.16]) in the third RCT. The follow-up for observational studies ranged from 3 to 15 years. Ten observational studies showed reduced incidence of dementia. Seven showed no association with incident dementia. Three studies showed decline in cognition was similar, whereas one showed slower decline with statin use. There was no evidence of adverse cognitive effects, including incidence of dementia, deterioration in global cognition, or specific cognitive domains associated with statin use in individuals aged ≥60 years. Future studies should examine this association in studies with longer follow-up periods.

Drug therapies for chronic conditions and risk of Alzheimer's disease and related dementias: A scoping review

INTRODUCTION

Most older Americans use drug therapies for chronic conditions. Several are associated with risk of Alzheimer's disease and related dementias (ADRD).

METHODS

A scoping review was used to identify drug classes associated with increasing or decreasing ADRD risk. We analyzed size, type, and findings of the evidence.

RESULTS

We identified 29 drug classes across 11 therapeutic areas, and 404 human studies. Most common were studies on drugs for hypertension (93) or hyperlipidemia (81). Fewer than five studies were identified for several anti-diabetic and anti-inflammatory drugs. Evidence was observational only for beta blockers, proton pump inhibitors, benzodiazepines, and disease-modifying anti-rheumatic drugs. For 13 drug classes, 50% or more of the studies reported consistent direction of effect on risk of ADRD.

DISCUSSION

Future research targeting drug classes with limited/non-robust evidence, examining sex, racial heterogeneity, and separating classes by molecule, will facilitate understanding of associated risk, and inform clinical and policy efforts to alleviate the growing impact of ADRD.

Efficacy of Antiplatelet Agent Usage for Primary and Secondary Prevention in Dialysis Patients: a Nationwide Data Survey and Propensity Analysis

BACKGROUND

Although cardiovascular (CV) disease is the leading cause of mortality and morbidity in dialysis patients, there is little evidence to guide the use of antiplatelet agents in dialysis patients.

METHOD

A nationwide database (Registry for Catastrophic Illnesses) for Taiwan, which has data from nearly all patients who received dialysis therapy from 1995 to 2008, was used. This is a population-based cohort study with time to event analyses to estimate the relation between antiplatelet agent use and outcomes. Hazard ratios were calculated to evaluate the effect of antiplatelet agent use on the risk of major CV events and mortality. Baseline characteristics were matched by propensity score (PS).

RESULTS

A total of 71,835 were included, and 10,595 (14.7%) patients received an anti-platelet agent. The median value of follow-up days was 61.6 months. After PS-based matching, 9598 patients who used an antiplatelet agent and 23,794 non-users were included in the analysis. After PS matching, there was no difference between patients using an antiplatelet agent or not in CV events (p = 0.672) and total mortality (p = 0.529). A subgroup analysis of different usage periods of antiplatelet agents indicated that CV events and total mortality were similar in those who used antiplatelet agents for short or long durations. In subgroup analysis, there was also no difference between patients with a different modality of dialysis (hemodialysis or peritoneal dialysis), different antiplatelet agents (aspirin, clopidogrel, and/or ticlopidine) or patients with/without previous cardiovascular disease in CV events and total mortality.

CONCLUSIONS

Antiplatelet agent usage does not reduce CV events and total mortality in dialysis patients.

Hypoglycemia and Dementia Risk in Older Patients with Type 2 Diabetes Mellitus: A Propensity-Score Matched Analysis of a Population-Based Cohort Study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with an increased risk for dementia. The effects of hypoglycemia on dementia are controversial. Thus, we evaluated whether hypoglycemia increases the risk for dementia in senior patients with T2DM.

METHODS

We used the Korean National Health Insurance Service Senior cohort, which includes >10% of the entire senior population of South Korea. In total, 5,966 patients who had ever experienced at least one episode of hypoglycemia were matched with those who had not, using propensity score matching. The risk of dementia was assessed through a survival analysis of matched pairs.

RESULTS

Patients with underlying hypoglycemic events had an increased risk for all-cause dementia, Alzheimer's dementia (AD), and vascular dementia (VaD) compared with those who had not experienced a hypoglycemic event (hazard ratio [HR], 1.254; 95% confidence interval [CI], 1.166 to 1.349; P<0.001 for all-cause dementia; HR, 1.264; 95% CI, 1.162 to 1.375; P<0.001 for AD; HR, 1.286; 95% CI, 1.110 to 1.490; P<0.001 for VaD). According to number of hypoglycemic episodes, the HRs of dementia were 1.170, 1.201, and 1.358 in patients with one hypoglycemic episode, two or three episodes, and more than three episodes, respectively. In the subgroup analysis, hypoglycemia was associated with an increased risk for dementia in both sexes with or without T2DM microvascular or macrovascular complications.

CONCLUSION

Our findings suggest that patients with a history of hypoglycemia have a higher risk for dementia. This trend was similar for AD and VaD, the two most important subtypes of dementia.

Aspirin and Risk of Dementia in Patients with Late-Onset Depression: A Population-Based Cohort Study

Background

Late onset depression (LOD) often occurs in the context of vascular disease and may be associated with risk of dementia. Aspirin is widely used to reduce the risk of cardiovascular disease and stroke. However, its role in patients with LOD and risk of dementia remains inconclusive. Materials and Methods. A population-based study was conducted using data from National Health Insurance of Taiwan during 1996–2009. Patients fulfil diagnostic criteria for LOD with or without subsequent dementia (incident dementia) and among whom users of aspirin (75 mg daily for at least 6 months) were identified. The time-dependent Cox proportional hazards model was applied for multivariate analyses. Propensity scores with the one-to-one nearest-neighbor matching model were used to select matching patients. Cumulative incidence of incident dementia after diagnosis of LOD was calculated by Kaplan–Meier Method.

Results

A total of 6028 (13.4%) and 40,411 (86.6%) patients were defined as, with and without diagnosis of LOD, among whom 2,424 (41.9%) were aspirin users. Patients with LOD had more comorbidities such as cardiovascular diseases, diabetes, and hypertension comparing to those without LOD. Among patients with LOD, aspirin users had lower incidence of subsequent incident dementia than non-users (Hazard Ratio = 0.734, 95% CI 0.641–0.841, p < 0.001). After matching aspirin users with non-users by propensity scores-matching method, the cumulative incidence of incident dementia was significantly lower in aspirin users of LOD patients (p < 0.001). After matching aspirin users with non-users by propensity scores-matching method, the cumulative incidence of incident dementia was significantly lower in aspirin users of LOD patients (

Conclusions

Aspirin may be associated with a lower risk of incident dementia in patients with LOD. This beneficial effect of aspirin in LOD patients needs validation in prospective clinical trials and our results should be interpreted with caution.

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.

Drug interactions with dementia-related pathophysiological pathways worsen or prevent dementia

Many risk factors are known to induce or precipitate dementia. Drugs acting via different mechanisms can modulate cognitive performance and exert either beneficial or deleterious effects on cognition through functional or neuropathological mechanisms. This review discusses the association between several classes of drugs and cognitive impairment and dementia risk. These drugs can be divided into drugs targeting CNS disorders (e.g., anticholinergic drugs, antiepileptics, antipsychotics, benzodiazepines, and opioids) and drugs targeting non‐CNS disorders (e.g., antidiabetics, antihypertensives, proton pump inhibitors, and statins). Furthermore, we sought to highlight the pharmacological mechanisms underlying their possible detrimental or beneficial effects on cognition. Anticholinergic and antiepileptic drugs were excluded from this review because their effects on cognition are well known. Studies investigating benzodiazepines have revealed an increased risk of dementia. Conclusions on dementia risk or cognitive impairment regarding opioids and antipsychotic drugs are difficult to draw. These different classes appear to impair cognition not by a single clear mechanism of action specific to each class but by several relatively interdependent and interconnected mechanisms (e.g., impaired neurotransmission, neuroinflammation, neuronal death, oxidative stress, or interactions with dementia‐related pathways). The dementia risk initially associated with the use of proton pump inhibitors might have been overestimated. In contrast, statins, antihypertensive medications, and antidiabetics could potentially decrease the risk of dementia and cognitive impairment by acting in ways opposite to the mechanisms cited above.

Linked Articles

This article is part of a themed section on Therapeutics for Dementia and Alzheimer's Disease: New Directions for Precision Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.18/issuetoc

High exposure to statins decrease the risk of new-onset dementia: A nationwide population-based longitudinal cohort study

Several studies have shown that statin users have a lower risk of new-onset dementia (NOD) compared nonusers. However, other studies have shown opposite results. In this study, we investigated the association between the use of statins and the development of NOD.This was a longitudinal cohort study using data from claim forms submitted to the Taiwanese Bureau of National Health Insurance. The study included patients with NOD and non-NOD subjects from January 2002 to December 2013. We estimated the hazard ratios (HRs) of NOD associated with statin use, whereas nonuser subjects were used as a reference group.A total of 19,522 NOD cases were identified in 100,610 hyperlipidemic patients during the study period. The risk of NOD, after adjusting for sex, age, comorbidities, and concurrent medication, was lower among statin users than nonusers (HR 0.95, 95% CI [confidence interval] 0.94-0.96; P < .001). The adjusted HRs for NOD were 1.53 (95% CI, 1.45-1.62), 0.63 (95% CI, 0.57-0.71), and 0.34 (95% CI, 0.30-0.38) when the cumulative defined daily doses ranged from 28 to 365, 366 to 730, and more than 730 relative to nonusers, respectively.We concluded that statin use is associated with a decreased NOD risk. The protective effect of statins for NOD seemed to be related to high exposure to statins. This study also highlights that high exposure to statins has a dose-response effect on lowering NOD risk.

Does Treating Vascular Risk Factors Prevent Dementia and Alzheimer's Disease? A Systematic Review and Meta-Analysis

BACKGROUND

Epidemiological evidence has associated Alzheimer's disease (AD) with vascular risk factors (VRFs), but whether treatment of VRFs reduces the incidence of dementia and AD is uncertain.

OBJECTIVE

To conduct a systematic review and meta-analysis to summarize available data on the impact of treatment of VRFs on dementia and AD incidence.

METHODS

Pertinent studies published until 1 January 2018 were identified from PubMed. Both randomized controlled trials (RCT) and prospective studies that investigated the impact of treatment of VRFs on dementia or AD incidence were included.

RESULTS

Eight RCTs and 52 prospective studies were identified. Antihypertensive treatment was associated with a non-significant reduced risk of dementia in RCTs (n = 5; relative risk [RR], 0.84; 95% confidence interval [CI], 0.69-1.02) and prospective studies (n = 3; RR, 0.77; 95% CI, 0.58-1.01) and with reduced AD risk in prospective studies (n = 5; RR = 0.78; 95% CI, 0.66-0.91). In prospective studies, treatment of hyperlipidemia with statins, but not nonstatin lipid-lowering agents, was associated with reduced risk of dementia (n = 17; RR, 0.77; 95% CI, 0.63-0.95) and AD (n = 13; RR, 0.86; 95% CI, 0.80-0.92). The single RCT on statins and dementia incidence showed no association. Data from one RCT and six prospective studies did not support a beneficial impact of antidiabetic drugs or insulin therapy on dementia risk.

CONCLUSION

Current evidence indicates that antihypertensives and statins might reduce the incidence of dementia and AD. Further trials to determine the effect of VRF on AD are needed.

The role of APOE4 in Alzheimer's disease: strategies for future therapeutic interventions

Alzheimer’s disease (AD) is the leading cause of dementia affecting almost 50 million people worldwide. The ε4 allele of Apolipoprotein E (APOE) is the strongest known genetic risk factor for late-onset AD cases, with homozygous APOE4 carriers being approximately 15-times more likely to develop the disease. With 25% of the population being APOE4 carriers, understanding the role of this allele in AD pathogenesis and pathophysiology is crucial. Though the exact mechanism by which ε4 allele increases the risk for AD is unknown, the processes mediated by APOE, including cholesterol transport, synapse formation, modulation of neurite outgrowth, synaptic plasticity, destabilization of microtubules, and β-amyloid clearance, suggest potential therapeutic targets. This review will summarize the impact of APOE on neurons and neuronal signaling, the interactions between APOE and AD pathology, and the association with memory decline. We will then describe current treatments targeting APOE4, complications associated with the current therapies, and suggestions for future areas of research and treatment.

Risk of Heart Failure Hospitalization Associated With Cilostazol in Diabetes: A Nationwide Case-Crossover Study

Background and Objective: It has been suggested to avoid cilostazol, the first-line therapy for peripheral arterial disease, in patients with congestive heart failure (HF). The objective of this study was to evaluate the risk of hospitalization for heart failure (HHF) associated with cilostazol use in the patients of diabetes mellitus. Methods: This case-crossover study retrieved records on diabetic patients > 20 years of age who were hospitalized for heart failure during the period of 2009-2011 from the Taiwan National Health Insurance Database. The "current" period was defined as 1-30 days prior to HHF whereas the 91-120 days prior to HHF served as the "reference" period. The exposure status just preceding the event is compared with exposure of the same person in one or more referent remote to the event. Adjusted odds ratios (OR) were used to estimate time-varying discordant exposure by the ratio of the number exposed to cilostazol only during the case period to the number exposed to cilostazol only during the control period. Results: A total of 47,506 diabetic patients were included in the analysis (average age: 72.7 ± 12.4, percentage of males: 48%). A total of 399 patients (0.84%) received cilostazol only in the current period, and 252 (0.53%) received cilostazol only in the reference period. After adjustment for other medications, a significant association was found between cilostazol and HHF (OR: 1.35, 95% CI: 1.14-1.59). After further adjustment for time-varying co-morbidities the ORs remained essentially the same. Sensitivity analyses using different definitions of control period (ranging from 31-60, 61-90, to 121-150 days before index date) yielded adjusted ORs of 1.43 (95% CI: 1.14-1.79), 1.31 (95% CI: 1.09-1.57) and 1.23 (95% CI: 1.06-1.44), respectively suggesting the robustness of our study findings. Conclusion: Use of cilostazol may be positively related to the risk of HHF. Further studies are warranted to explore the underlying mechanisms and to confirm the association.

Connecting the brain cholesterol and renin-angiotensin systems: potential role of statins and RAS-modifying medications in dementia

Millions of people worldwide receive agents targeting the renin-angiotensin system (RAS) to treat hypertension or statins to lower cholesterol. The RAS and cholesterol metabolic pathways in the brain are autonomous from their systemic counterparts and are interrelated through the cholesterol metabolite 27-hydroxycholesterol (27-OHC). These systems contribute to memory and dementia pathogenesis through interference in the amyloid-beta cascade, vascular mechanisms, glucose metabolism, apoptosis, neuroinflammation and oxidative stress. Previous studies examining the relationship between these treatments and cognition and dementia risk have produced inconsistent results. Defining the blood-brain barrier penetration of these medications has been challenging, and the mechanisms of action on cognition are not clearly established. Potential biases are apparent in epidemiological and clinical studies, such as reverse epidemiology, indication bias, problems defining medication exposure, uncertain and changing doses, and inappropriate grouping of outcomes and medications. This review summarizes current knowledge of the brain cholesterol and RAS metabolism and the mechanisms by which these pathways affect neurodegeneration. The putative mechanisms of action of statins and medications inhibiting the RAS will be examined, together with prior clinical and animal studies on their effects on cognition. We review prior epidemiological studies, analysing their strengths and biases, and identify areas for future research. Understanding the pathophysiology of the brain cholesterol system and RAS and their links to neurodegeneration has enormous potential. In future, well-designed epidemiological studies could identify potential treatments for Alzheimer's disease (AD) amongst medications that are already in use for other indications.

Overview the effect of statin therapy on dementia risk, cognitive changes and its pathologic change: a systematic review and meta-analysis

Background

Many studies have reported on the role of statin therapy in dementia, but its efficacy remains controversial. We aimed to search for reliable and meaningful articles to assess the efficacy of statin therapy for dementia risk, cognitive items, and pathologic markers.

Methods

Related literature for this study was published in the period from January 1, 1987 to January 1, 2018. Odds ratio (OR) and 95% confidence interval (95% CI) estimates were pooled in either fixed or random effects models.

Results

A total of 23 relevant studies were included after the application of the search strategy. The pooled results showed that statin therapy would downregulate dementia risk according to an analysis of 1,314,431 dementia patients and 1,836,539 healthy controls (OR: 0.64, 95% CI: 0.50, 0.81). In addition, specific changes in mini-mental state examination (MMSE) score were observed in individuals with dementia with statin therapy (OR: 0.46, 95% CI: 0.17, 0.74). However, the results of this meta-analysis showed that statin therapy did not significantly modify the Alzheimer's Disease Assessment Scale (ADAS-cog) score (OR: -0.26, 95% CI: -1.13, 0.62). No significant association was found between statin therapy and activities of daily living performance (OR: -0.69, 95% CI: -4.12, 2.74). When investigating pathological markers, our results indicated a significant influence of statin therapy on plasma amyloid β₄₀ (Aβ₄₀) (OR: 9.27, 95% CI: 0.71, 17.84), plasma Aβ₄₂ (OR: 2.60, 95% CI: 1.07, 4.13), plasma low-density lipoprotein (LDL) cholesterol (OR: -16.95, 95% CI: -25.54, -8.37), plasma lathosterol (OR: -0.11, 95% CI: -0.14, -0.07), plasma 24s-hydroxycholesterol (OR: -10.41, 95% CI: -15.57, -5.25), and cerebrospinal fluid (CSF) lathosterol (OR: -0.07, 95% CI: -0.12, -0.01).

Conclusions

The available data indicate that statin therapy may reduce dementia risk, altering cognitive items and pathologic markers.

Statin reduces the risk of dementia in diabetic patients receiving androgen deprivation therapy for prostate cancer

BACKGROUND

Androgen deprivation therapy (ADT) has been reported to increase the risk of dementia. Statin use decreases the risk of dementia. This study is aimed to investigate the association of statin use and dementia in type 2 diabetic (T2DM) patients receiving ADT.

METHODS

Using the National Health Insurance Research Database of Taiwan, we conducted a population-based nationwide cohort study of T2DM patients newly diagnosed with prostate cancer (PCa) between 1998 and 2013. To test statin effects on dementia in T2DM patients receiving ADT, cox proportional hazards models with 1:1 propensity score-matched analysis were used. We divided the study subjects into a statin group and a statin-naive group. The primary outcome was dementia.

RESULTS

Of the 9855 selected T2DM patients newly diagnosed with PCa between 1998 and 2013, 5427 patients received ADT for their PCa. After propensity score matching, 1006 statin users and 1006 non-statin users were included in the study cohort, with a mean follow-up period of 3.5 years for the statin group. Among those patients, 179 (8.7%) were newly diagnosed with dementia. A propensity score-matched analysis (hazard ratio = 0.70, 95% confidence interval = 0.52-0.94) demonstrated a significantly decreased risk of subsequent dementia in the statin users with an absolute risk reduction by 1%. A significant decrease in the risk of dementia with increasing statin duration was also demonstrated (P for trend = 0.002).

CONCLUSIONS

Statin use in T2DM patients receiving ADT for PCa had decreased risk of dementia, with statin adherence and intensity augmenting this benefit.

Increased Risk of Dementia in Patients with Antidepressants: A Meta-Analysis of Observational Studies

Antidepressants are the most commonly and widely used medication for its effectiveness in the treatment of anxiety and depression. A few epidemiological studies have documented that antidepressant is associated with increased risk of dementia so far. Here, our aim is to assess the association between antidepressant use and risk of dementia in elderly patients. We searched articles through MEDLINE, EMBASE, Google, and Google Scholar from inception to December 1, 2017, that reported on the association between antidepressant use and dementia risk. Data were collected from each study independently, and study duplication was checked by at least three senior researchers based on a standardized protocol. Summary relative risk (RR) with 95% CI was calculated by using a random-effects model. We selected 9 out of 754 unique abstracts for full-text review using our predetermined selection criteria, and 5 out of these 9 studies, comprising 53,955 participants, met all of our inclusion criteria. The overall pooled RR of dementia was 1.75 (95% CI: 1.033–2.964) for SSRIs whereas the overall pooled RR of dementia was 2.131 (95% CI: 1.427–3.184) for tricyclic use. Also, MAOIs showed a high rate of increase with significant heterogeneity. Our findings indicate that antidepressant use is significantly associated with an increased risk of developing dementia. Therefore, we suggest physicians to carefully prescribe antidepressants, especially in elder patients. Additionally, treatment should be stopped if any symptoms related to dementia are to be noticed.

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.

Early Statin Use and the Progression of Alzheimer Disease: A Total Population-Based Case-Control Study

The protective effect of statin on Alzheimer disease (AD) is still controversial, probably due to the debate about when to start the use of statin and the lack of any large-scale randomized evidence that actually supports the hypothesis. The purpose of this study was to examine the protective effect of early statin use on mild-to-moderate AD in the total Taiwanese population.This was a total population-based case-control study, using the total population of Taiwanese citizens seen in general medical practice; therefore, the findings can be applied to the general population. The study patients were those with newly diagnosed dementia (ICD-9 290.x) and prescribed any acetylcholinesterase inhibitors (AChEI) from the Taiwan National Health Insurance dataset in 1997 to 2008. The newly diagnosed eligible mild-to-moderate AD patients were traced from the dates of their index dates, which was defined as the first day to receive any AChEI treatment, back to 1 year (exposure period) to categorize them into AD with early statin use and without early statin use. Early statin use was defined as patients using statin before AChEI treatment. Alzheimer disease patients with early statin use were those receiving any statin treatment during the exposure period. Then, we used propensity-score-matched strategy to match these 2 groups as 1:1. The matched study patients were followed-up from their index dates. The primary outcome was the discontinuation of AChEI treatment, indicating AD progression.There were 719 mild-to-moderate AD-paired patients with early statin use and without early statin use for analyses. Alzheimer disease progression was statistically lower in AD patients with early statin use than those without (P = 0.00054). After adjusting for other covariates, mild-to-moderate AD patients with early stain use exhibited a 0.85-risk (95% CI = 0.76-0.95, P = 0.0066) to have AD progression than those without.Early statin use was significantly associated with a reduction in AD progression in mild-to-moderate AD patients. The future randomized trial studies can confirm our findings.

Association of Statins with Sensory and Autonomic Ganglionopathy

Objective

To examine if statins have an effect on small nerve fibers.

Methods

This retrospective study evaluated the effect of statins in pure small-fiber neuropathy (SFN). Outcome measures were symptom scales (numbness, tingling, and autonomic symptoms), skin biopsies assessing epidermal nerve fiber density (ENFD), sweat gland nerve fiber density (SGNFD), and quantitative autonomic testing.

Results

One hundred and sixty participants with pure SFN were identified. Eighty participants (women/men, age ± SD 33/47, 68.1 ± 11.6 years old) were on statins for 53.5 ± 28.7 months to treat dyslipidemia and they were age and gender matched with 80 participants (33/47, 68.1 ± 9.5) that were off statins. ANOVA showed reduced ENFD/SGNFD at the proximal leg in the statin group [(count/mm) 8.3 ± 3.6/51.3 ± 14.2] compared to the off statin group (10.4 ± 3.8, p = 0.0008/56.4 ± 12.7, p = 0.018). There was no difference in ENFD/SGNFD at the distal leg in the statin group (4.9 ± 3.2/39.8 ± 15.7) compared to the off statin group (5.9 ± 3.4, p = 0.067/41.8 ± 15.9, p = 0.426). Statins did not affect symptom scales and the outcome of autonomic testing.

Conclusion

Statin use is associated with degeneration of sensory and autonomic fibers. The pattern of abnormalities, e.g., degeneration of proximal while sparing of distal fibers, is consistent with a non-length-dependent process with lesions in the dorsal root and the autonomic ganglia. The statin-associated sensory and autonomic ganglionopathy is mild.

Impact on cognitive function-are all statins the same?

Dementia is a major public health concern, affecting an estimated 7% of the population over 65 and 30% over 80 years of age. There is mounting evidence in the literature from meta-analyses of high-quality prospective cohort studies that statins may have a positive impact in reducing the incidence of dementia. Little is known, however, on whether certain types of statins are more impactful than others. This narrative review specifically explores the various properties of different statin types and whether these differences lead to a clinically significant differential impact on cognitive function. We critically evaluate the literature, emphasizing interesting and important new findings, and overall aim to bring the reader up-to-date on evidence-based recommendations.

Statin Use, Incident Dementia and Alzheimer Disease in Elderly African Americans

OBJECTIVE

To investigate the association between statin use, incident dementia, and Alzheimer disease (AD) in a prospective elderly African American cohort.

DESIGN

Two stage design with a screening interview followed by a comprehensive in-home assessment conducted over an eight-year period. Diagnoses of incident AD and dementia were made by consensus. Statin use was collected at each evaluation. Measurements of low-density lipoprotein cholesterol (LDL), C-reactive protein (CRP) and APOE genotype were obtained from baseline blood samples. Logistic regression models were used to test the association of statin use on incident dementia and AD and its possible association with lipid and CRP levels.

SETTING

Indianapolis, Indiana.

PARTICIPANTS

From an original cohort of 2629 participants, a subsample of 974 African Americans aged >70 years with normal cognition, at least one follow up evaluation, complete statin information, and biomarker availability were included.

MAIN OUTCOME MEASURES

Incident dementia and incident AD.

RESULTS

After controlling for age at diagnosis, sex, education level, presence of the APOE ε4 allele and history of stroke for the incident dementia model, baseline use of statins was associated with a significantly decreased risk of incident dementia (OR=.44, P=.029) and incident AD (OR=.40, P=.029). The significant effect of statin use on reduced AD risk and trend for dementia risk was found only for those participants who reported consistent use over the observational period (incident AD: P=.034; incident dementia: P=.061). Additional models found no significant interaction between baseline statin use, baseline LDL, or CRP level and incident dementia/AD.

CONCLUSIONS

Consistent use of statin medications during eight years of follow-up resulted in significantly reduced risk for incident AD and a trend toward reduced risk for incident dementia.

Effects of angiotensin converting enzyme inhibition or angiotensin receptor blockade in dialysis patients: a nationwide data survey and propensity analysis

Long-term benefit of using a renin-angiotensin-aldosterone system blocker such as an angiotensin-converting enzyme inhibitor (ACEI) or an angiotensin II receptor blocker (ARB) for patients already receiving dialysis remains undetermined. The aim of this study is to assess the efficacy and safety of ACEI or ARB use in dialysis patients. We performed a population-based cohort study with time-to-event analyses to estimate the relation between the use of ACEI/ARB and their outcomes. We used a nationwide database (Registry for Catastrophic Illnesses) for Taiwan, which has data from 1995 to 2008 nearly of all patients who received dialysis therapy. The records of all dialysis patients aged ≥18 with no evidence of cardiovascular (CV) events in 1997 and 1998 (133,564 patients) were examined. Users (n = 50,961) and nonusers (n = 59,913) of an ACEI/ARB were derived. We then used propensity score matching and Cox proportional hazards regression models to estimate adjusted hazard ratios (HRs) for all-cause mortality and CV events in users and nonusers of an ACRI/ARB. The 15,182 patients, who used an ACEI/ARB, and the 15,182 nonusers had comparable baseline characteristics during the 14 years of follow-up. The mortality was significantly greater in patients who did not use an ACEI/ARB (HR = 0.90, 95% confidence interval = 0.86-0.93). Subgroup analysis of 3 tertiles of patients who used different total amounts of ACEI/ARB during the study period indicated that CV events were more common in patients who used an ACEI/ARB for a short duration (tertile 1: HR = 1.63), but less common in those who used an ACEI/ARB for long durations (tertile 2: HR = 1.05; tertile 3: HR = 0.94; trend for declining HR from tertile 1 to 3: P < 0.001). The mortality benefit provided by use of an ACEI/ARB was consistent across most patient subgroups, as was the benefit of ARB monotherapy rather than ACEI monotherapy. Independent of traditional risk factors, overall mortality was significantly lower in dialysis patients who used an ACEI/ARB. In addition, subjects who used an ACEI/ARB for longer durations were significantly less likely to experience CV events.