Antihypertensive drugs, prevention of cognitive decline and dementia: a systematic review of observational studies, randomized controlled trials and meta-analyses, with discussion of potential mechanisms

Stroke and dementia risk: A systematic review and meta-analysis

INTRODUCTION

Stroke is an established risk factor for all-cause dementia, though meta-analyses are needed to quantify this risk.

METHODS

We searched Medline, PsycINFO, and Embase for studies assessing prevalent or incident stroke versus a no-stroke comparison group and the risk of all-cause dementia. Random effects meta-analysis was used to pool adjusted estimates across studies, and meta-regression was used to investigate potential effect modifiers.

RESULTS

We identified 36 studies of prevalent stroke (1.9 million participants) and 12 studies of incident stroke (1.3 million participants). For prevalent stroke, the pooled hazard ratio for all-cause dementia was 1.69 (95% confidence interval: 1.49-1.92; P < .00001; I2 = 87%). For incident stroke, the pooled risk ratio was 2.18 (95% confidence interval: 1.90-2.50; P < .00001; I2 = 88%). Study characteristics did not modify these associations, with the exception of sex which explained 50.2% of between-study heterogeneity for prevalent stroke.

DISCUSSION

Stroke is a strong, independent, and potentially modifiable risk factor for all-cause dementia.

The association of multiple anti-hypertensive medication classes with Alzheimer's disease incidence across sex, race, and ethnicity

BACKGROUND

Antihypertensive treatments have been shown to reduce the risk of Alzheimer's disease (AD). The renin-angiotensin system (RAS) has been implicated in AD, and thus RAS-acting AHTs (angiotensin converting enzyme inhibitors (ACEIs), and angiotensin-II receptor blockers (ARBs)) may offer differential and additional protective benefits against AD compared with other AHTs, in addition to hypertension management.

METHODS

In a retrospective cohort design, we examined the medical and pharmacy claims of a 20% sample of Medicare beneficiaries from 2007 to 2013, and compared rates of AD diagnosis for 1,343,334 users of six different AHT drug treatments, 65 years of age or older (4,215,338 person-years). We compared AD risk between RAS and non-RAS AHT drug users, and between ACEI users and ARB users, by sex and race/ethnicity. Models adjusted for age, socioeconomic status, underlying health, and comorbidities.

FINDINGS

RAS-acting AHTs were slightly more protective against onset of AD than non-RAS-acting AHTs for males, (male OR = 0.931 (CI: 0.895-0.969)), but not so for females (female OR = 0.985 (CI: 0.963-1.007)). Relative to other AHTs, ARBs were superior to ACEIs for both men (male ARB OR = 0.834 (CI: 0.788-0.884); male ACEI OR = 0.978 (CI: 0.939-1.019)) and women (female ARB OR = 0.941 (CI: 0.913-0.969); female ACEI OR = 1.022 (CI: 0.997-1.048)), but only in white men and white and black women. No association was shown for Hispanic men and women.

CONCLUSION

Hypertension management treatments that include RAS-acting ARBs may, in addition to lowering blood pressure, reduce AD risk, particularly for white and black women and white men. Additional studies and clinical trials that include men and women from different racial and ethnic groups are needed to confirm these findings. Understanding the potentially beneficial effects of certain RAS-acting AHTs in high-risk populations is of great importance.

Diabetes and anxiety adversely affect cognition in multiple sclerosis

OBJECTIVE

To determine whether comorbid diabetes and hypertension are associated with cognition in multiple sclerosis (MS) after accounting for psychiatric comorbidities.

METHODS

Participants completed a structured psychiatric interview, the Hospital Anxiety and Depression Scale (HADS), a comorbidity questionnaire, and cognitive testing including the Symbol Digit Modalities Test (SDMT), California Verbal Learning Test (CVLT-II), Brief Visuospatial Memory Test-Revised (BVMT-R), and verbal fluency. Test scores were converted to age-, sex- and education-adjusted z-scores. We evaluated associations between diabetes and hypertension and the four cognitive z-scores using a multivariate linear model, adjusting for comorbid depression and anxiety disorders, psychotropic medications, disease-modifying therapies, smoking status and body mass index.

RESULTS

Of 111 participants, most were women (82.9%) with relapsing remitting MS (83.5%), of mean (SD) age 49.6 (12.7) years. Comorbidity was common; 22.7% participants had hypertension, 10.8% had diabetes, 9.9% had current major depression, and 9.9% had current anxiety disorders. Mean (SD) z-scores were: SDMT -0.66 (1.15), CVLT-II -0.43 (1.32), BVMT-R -0.49 (1.07) and fluency -0.59 (0.86). Diabetes (p = 0.02) and anxiety disorder (p = 0.02) were associated with cognitive function overall. Diabetes was associated with lower BVMT-R (β = -1.18, p = 0.0015) and fluency (β = -0.63, p = 0.037) z-scores. Anxiety was associated with lower SDMT (β = -1.07, p = 0.0074) z-scores. Elevated anxiety symptoms (HADS-A ≥ 11) were associated with lower z-scores on the SDMT and CVLT-II.

CONCLUSION

Comorbidities, including diabetes and anxiety, are associated with cognitive dysfunction in MS. Their presence may contribute to the heterogeneous pattern of impairments seen across individuals and they may represent targets for improved management of cognitive symptoms.

The association between blood pressure variability (BPV) with dementia and cognitive function: a systematic review and meta-analysis protocol

BACKGROUND

A body of empirical work demonstrates that wide fluctuations in a person's blood pressure across consecutive measures, known as blood pressure variability (BPV), hold prognostic value to predict stroke and transient ischemic attack. However, the magnitude of association between BPV and other neurological outcomes remains less clear. This systematic review aims to pool together data regarding BPV with respect to incident dementia, cognitive impairment, and cognitive function.

METHODS

Electronic databases (MEDLINE, EMBASE, and SCOPUS) will be searched for the key words blood pressure variability and outcomes of dementia, cognitive impairment, and cognitive function. Authors and reference lists of included studies will also be contacted to identify additional published and unpublished studies. Eligibility criteria are as follows: population-adult humans (over 18 years but with no upper age limit) without dementia at baseline, with or without elevated blood pressure, or from hypertensive populations (systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg or use of antihypertensive drug for hypertension) and from primary care, community cohort, electronic database registry, or randomized controlled trial (RCT); exposure-any metric of BPV (systolic, diastolic or both) over any duration; comparison-persons without dementia who do not have elevated BPV; and outcome-dementia, cognitive impairment, cognitive function at follow-up from standardized neurological assessment, or cognitive testing. Article screening will be undertaken by two independent reviewers with disagreements resolved through discussion. Data extraction will include original data specified as hazard ratios, odds ratios, correlations, regression coefficients, and original cell data if available. Risk of bias assessment will be undertaken by two independent reviewers. Meta-analytic methods will be used to synthesize the data collected relating to the neurological outcomes with Comprehensive Meta-Analysis Version 2.0 (Biostat Inc., Engelwood, NJ).

DISCUSSION

This systematic review aims to clarify whether BPV is associated with elevated risk for dementia, cognitive impairment, and cognitive function. An evaluation of the etiological links between BPV with incident dementia might inform evidence-based clinical practice and policy concerning blood pressure measurement and hypertension management. The review will identify sources of heterogeneity and may inform decisions on whether it is feasible and desirable to proceed with an individual participant data meta-analysis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017081977.

Angiotensin receptor (AT2R) agonist C21 prevents cognitive decline after permanent stroke in aged animals-A randomized double- blind pre-clinical study

Post stroke cognitive impairment (PSCI) is an understudied, long-term complication of stroke, impacting nearly 30-40% of all stroke survivors. No cure is available once the cognitive deterioration manifests. To our knowledge, this is the first study to investigate the long-term effects of C21 treatment on the development of PSCI in aged animals. Treatments with C21 or vehicle were administered orally, 24 h post-stroke, and continued for 30 days. Outcome measures for sensorimotor and cognitive function were performed using a sequence of tests, all blindly conducted and assessed at baseline as well as at different time points post-stroke. Our findings demonstrate that the angiotensin receptor (AT2R) agonist C21 effectively prevents the development of PSCI in aged animals.

Associations between modifiable lifestyle factors and multidimensional cognitive health among community-dwelling old adults: stratified by educational level

ABSTRACTBackground:Cognition is multidimensional, and each domain plays a unique and crucial part in successful daily life engagement. However, less attention has been paid to multi-domain cognitive health for the elderly, and the role of lifestyle factors in each domain remains unclear.

METHODS

We conducted a cross-sectional study of 3,230 older adults aged 60+ years in Xiamen, China, in 2016. The Montreal Cognitive Assessment (MoCA) was used to measure general cognition and six specific sub-domains. To account for educational effects, we adjusted the MoCA score and divided respondents into three education-specific groups (low, moderate, and high education groups with ≤5, 6~8, and ≥9 years of education, respectively). A series of proportional odds models were used to detect the associations between two categories of lifestyle factors - substance abuse (cigarette and alcohol) and leisure activity (TV watching, reading, smartphone use, social activity, and exercise) - and general cognition and the six sub-domains in those three groups.

RESULTS

Among the 3,230 respondents, 2,617 eligible participants were included with a mean age of 69.05 ± 7.07 years. Previous or current smoking/drinking was not associated with MoCA scores in the whole population, but unexpectedly, the ex-smokers in the low education group performed better in general cognition (OR = 2.22) and attention (OR = 2.05) than their never-smoking counterparts. Modest TV watching, reading, and smartphone use also contributed to better cognition among elderly participants in the low education group. For the highly educated elderly, comparatively longer reading (>3.5 hours/week) was inversely associated with general cognition (OR = 0.53), memory (OR = 0.59), and language (OR = 0.54), while adequate exercise (5~7 days/week) was positively related to these factors with OR = 1.48, OR = 1.49, and OR = 1.53, respectively. For the moderately educated elderly, only modest reading was significantly beneficial.

CONCLUSIONS

Lifestyle factors play different roles in multidimensional cognitive health in different educational groups, indicating that individual intervention strategies should be designed according to specific educational groups and different cognitive sub-domains.

Sex and Age Differences in the Association of Blood Pressure and Hypertension with Cognitive Function in the Elderly: The Rancho Bernardo Study

OBJECTIVES

This study examines sex and age differences in associations of systolic and diastolic blood pressure (SBP, DBP), pulse pressure and hypertension with cognitive function in a community-dwelling population.

DESIGN

Cross-sectional study.

SETTING

Research clinic visit in 1988-91.

PARTICIPANTS

Participants were 693 men and 1022 women aged 50-97 Measurements: Blood pressure was measured and 12 cognitive function tests were administered.

RESULTS

Average age was 73.8±9.9 in men and 73.2±9.3 in women; 62.6% of men and 63.4% of women were hypertensive (SBP≥140 mmHg, DBP≥90 mmHg, or antihypertensive medication use). Each 5-unit increment in SBP, DBP, or pulse pressure and categorical hypertension was associated with significantly increased odds of poor verbal fluency performance in men and poor Trails B performance in women, with strongest associations for hypertension (OR=1.97, CI:1.01,3.85 in men; OR=1.51, CI:1.01,2.26 in women). After age stratification, associations remained statistically significant in younger (<80 years ) but not older (≥80 years) participants.

CONCLUSION

Blood pressure as a continuous or categorical variable was associated with poor performance on cognitive function tests, but domains varied by sex and associations were found only in those younger than 80 years. The absent associations in those aged 80 years and older could support the hypothesis that increased blood flow is required to maintain cerebral perfusion with advancing age, or could reflect a survivor effect.

Effect of SSRI and calcium channel blockers on depression symptoms and cognitive function in elderly persons treated for hypertension: three city cohort study

ABSTRACTBackground:Emerging genetic, ex-vivo, and clinical trial evidence indicates that calcium channel blockers (CCB) can improve mood and cognitive function. The objective of this study was to examine the effect of selective serotonin reuptake inhibitor (SSRI) therapy augmented with CCB on depression and cognitive decline in an elderly population with hypertension.

METHODS

Prospective study of 296 persons treated with SSRI and antihypertensive drugs. Baseline and two year clinic assessments were used to categorize participants as users of SSRI + CCB (n = 53) or users of SSRI + other antihypertensives (n = 243). Clinic visits were performed up to four times in a ten-year period to assess depression and cognitive function.

RESULTS

The sample mean age was 75.2 ± 5.47 years and 78% of participants were female. At two year follow-up there was a significant group by time interaction showing lower Center for Epidemiological Studies-Depression (CESD) scores in the SSRI + CCB group, F(1,291) = 4.13, p = 0.043, η2p = 0.014. Over ten-years follow-up, SSRI + CCB use was associated with improved general cognitive function (Mini-Mental State Examination: β = 0.97; 95% CI 0.14 to 1.81, p = 0.023) and immediate visual memory (Boston Visual Retention Test: β = 0.69; 95% CI 0.06 to 1.32, p = 0.033).

CONCLUSION

The findings provide general population evidence that SSRI augmentation with CCB may improve depression and cognitive function.

Nilvadipine in mild to moderate Alzheimer disease: A randomised controlled trial

BACKGROUND

This study reports the findings of the first large-scale Phase III investigator-driven clinical trial to slow the rate of cognitive decline in Alzheimer disease with a dihydropyridine (DHP) calcium channel blocker, nilvadipine. Nilvadipine, licensed to treat hypertension, reduces amyloid production, increases regional cerebral blood flow, and has demonstrated anti-inflammatory and anti-tau activity in preclinical studies, properties that could have disease-modifying effects for Alzheimer disease. We aimed to determine if nilvadipine was effective in slowing cognitive decline in subjects with mild to moderate Alzheimer disease.

METHODS AND FINDINGS

NILVAD was an 18-month, randomised, placebo-controlled, double-blind trial that randomised participants between 15 May 2013 and 13 April 2015. The study was conducted at 23 academic centres in nine European countries. Of 577 participants screened, 511 were eligible and were randomised (258 to placebo, 253 to nilvadipine). Participants took a trial treatment capsule once a day after breakfast for 78 weeks. Participants were aged >50 years, meeting National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's disease Criteria (NINCDS-ADRDA) for diagnosis of probable Alzheimer disease, with a Standardised Mini-Mental State Examination (SMMSE) score of ≥12 and <27. Participants were randomly assigned to 8 mg sustained-release nilvadipine or matched placebo. The a priori defined primary outcome was progression on the Alzheimer's Disease Assessment Scale Cognitive Subscale-12 (ADAS-Cog 12) in the modified intention-to-treat (mITT) population (n = 498), with the Clinical Dementia Rating Scale sum of boxes (CDR-sb) as a gated co-primary outcome, eligible to be promoted to primary end point conditional on a significant effect on the ADAS-Cog 12. The analysis set had a mean age of 73 years and was 62% female. Baseline demographic and Alzheimer disease-specific characteristics were similar between treatment groups, with reported mean of 1.7 years since diagnosis and mean SMMSE of 20.4. The prespecified primary analyses failed to show any treatment benefit for nilvadipine on the co-primary outcome (p = 0.465). Decline from baseline in ADAS-Cog 12 on placebo was 0.79 (95% CI, -0.07-1.64) at 13 weeks, 6.41 (5.33-7.49) at 52 weeks, and 9.63 (8.33-10.93) at 78 weeks and on nilvadipine was 0.88 (0.02-1.74) at 13 weeks, 5.75 (4.66-6.85) at 52 weeks, and 9.41 (8.09-10.73) at 78 weeks. Exploratory analyses of the planned secondary outcomes showed no substantial effects, including on the CDR-sb or the Disability Assessment for Dementia. Nilvadipine appeared to be safe and well tolerated. Mortality was similar between groups (3 on nilvadipine, 4 on placebo); higher counts of adverse events (AEs) on nilvadipine (1,129 versus 1,030), and serious adverse events (SAEs; 146 versus 101), were observed. There were 14 withdrawals because of AEs. Major limitations of this study were that subjects had established dementia and the likelihood that non-Alzheimer subjects were included because of the lack of biomarker confirmation of the presence of brain amyloid.

CONCLUSIONS

The results do not suggest benefit of nilvadipine as a treatment in a population spanning mild to moderate Alzheimer disease.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02017340, EudraCT number 2012-002764-27.

RAS modulation prevents progressive cognitive impairment after experimental stroke: a randomized, blinded preclinical trial

BACKGROUND

With the aging population, the prevalence and incidence of cerebrovascular disease will continue to rise, as well as the number of individuals with vascular cognitive impairment/dementia (VCID). No specific FDA-approved treatments for VCID exist. Although clinical evidence supports that angiotensin receptor blockers (ARBs) prevent cognitive decline in older adults, whether ARBs have a similar effect on VCID after stroke is unknown. Moreover, these agents reduce BP, which is undesirable in the acute stroke period, so we believe that giving C21 in this acute phase or delaying ARB administration would enable us to achieve the neurovascular benefits without the risk of unintended and potentially dangerous, acute BP lowering.

METHODS

The aim of our study was to determine the impact of candesartan (ARB) or compound-21 (an angiotensin type 2 receptor--AT2R--agonist) on long-term cognitive function post-stroke, in spontaneously hypertensive rats (SHRs). We hypothesized that AT2R stimulation, either directly with C21, or indirectly by blocking the angiotensin type 1 receptor (AT1R) with candesartan, initiated after stroke, would reduce cognitive impairment. Animals were subjected to a 60-min transient middle cerebral artery occlusion and randomly assigned to either saline/C21 monotherapy, for the full study duration (30 days), or given sequential therapy starting with saline/C21 (7 days) followed by candesartan for the remainder of the study (21 days). Outcome measures included sensorimotor/cognitive-function, amyloid-β determination, and histopathologic analyses.

RESULTS

Treatment with RAS modulators effectively preserved cognitive function, reduced cytotoxicity, and prevented chronic-reactive microgliosis in SHRs, post-stroke. These protective effects were apparent even when treatment was delayed up to 7 days post-stroke and were independent of blood pressure and β-amyloid accumulation.

CONCLUSION

Collectively, our findings demonstrate that RAS modulators effectively prevent cognitive impairment after stroke, even when treatment is delayed.

Antihypertensive drugs and relevant cardiovascular pharmacotherapies and the risk of incident dementia in patients with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) and dementia are predominant among the elderly; patients with AF have an increased dementia risk. We aimed to study if prescribed antihypertensive drugs and cardiovascular pharmacotherapies are associated with a lower relative risk of dementia.

METHODS

All included patients were ≥45 years and diagnosed with AF in primary care; 12,096 (6580 men and 5516 women) in Sweden. We excluded patients with a dementia diagnosis before onset of AF. Cox regression was used (hazard ratios, HRs, and 95% confidence interval, CI) with adjustments for sex, age, socioeconomic factors and co-morbidities.

RESULTS

Incident dementia occurred in 750 patients (6.2%) during an average of 5.6 years of follow-up (a total of 69,214 person-years). Patients prescribed thiazides HR 0.81 (95% CI 0.66-0.99) and warfarin HR 0.78 (95% CI 0.66-0.92) had a lower risk of dementia than patients without these drugs. The use of 1-4 of the different antihypertensive drug classes (thiazides, beta blocker, vessel active calcium channel blockers or renin angiotensin aldosterone (RAAS) blockers) were associated with a reduction of incident dementia; HR 0.80 (95% CI 0.64-1.00) for one to two drugs, and HR 0.63 (95% CI 0.46-0.84) for three or four drugs, versus having no prescribed antihypertensive drugs. The combination of a RAAS-blocker and a thiazide was significant, HR 0.70 (95% CI 0.53-0.92), versus not having that particular combination prescribed, while RAAS-blockers or thiazides separately were not significant.

CONCLUSION

Prescribed antihypertensive drugs, including thiazide/RAAS-blocker combination therapy and use of warfarin, were associated with a decreased incidence of dementia.

The association between relevant comorbidities and dementia in patients with atrial fibrillation

Risk of dementia is increased in patients with atrial fibrillation (AF). We aimed to study associations between relevant comorbidities and prevalent as well as incident dementia in AF patients. Study population included all adults (n = 12,283) ≥ 45 years diagnosed with AF at 75 primary care centers in Sweden 2001-2007. Logistic regression was used to calculate odds ratios (OR) with 95% confidence intervals (95% CI) for associations between comorbidities and prevalent dementia. In a subsample (n = 12,096), (excluding patients with dementia diagnosed before AF onset), Cox regression was used to estimate hazard ratios (HR) with 95% CIs for association between comorbidities, and incident dementia, after adjustment for age, socioeconomic factors and anticoagulant treatment. Totally 937 patients (7.6%), 388 men (5.8%) and 549 women (9.7%), were diagnosed with dementia. After adjustments, prevalent dementia was more common in (ORs, 95% CI) men with congestive heart failure (CHF), stroke, and depression; in women with CHF and depression, and among women > 75 years with stroke, but less common in women with hypertension. During a 5.6-year follow-up (standard deviation 2.5), 750 patients (6.2%; 322 men, 4.9%, and 428 women, 7.8%) were diagnosed with incident dementia. An increased risk of incident dementia was found among men with diabetes and depression; a decreased risk among men and women with CHF, and among women with hypertension, myocardial infarction cerebrovascular diseases. The findings regarding incident dementia need to be interpreted with great caution, as they may have been subject to survival bias.

A Randomized, Double-Blinded, Placebo-Controlled Study to Compare the Safety and Efficacy of Low Dose Enhanced Wild Blueberry Powder and Wild Blueberry Extract (ThinkBlue™) in Maintenance of Episodic and Working Memory in Older Adults

Previous research has shown beneficial effects of polyphenol-rich diets in ameliorating cognitive decline in aging adults. Here, using a randomized, double blinded, placebo-controlled chronic intervention, we investigated the effect of two proprietary blueberry formulations on cognitive performance in older adults; a whole wild blueberry powder at 500 mg (WBP500) and 1000 mg (WBP1000) and a purified extract at 100 mg (WBE111). One hundred and twenty-two older adults (65–80 years) were randomly allocated to a 6-month, daily regimen of either placebo or one of the three interventions. Participants were tested at baseline, 3, and 6 months on a battery of cognitive tasks targeting episodic memory, working memory and executive function, alongside mood and cardiovascular health parameters. Linear mixed model analysis found intervention to be a significant predictor of delayed word recognition on the Reys Auditory Verbal Learning Task (RAVLT), with simple contrast analysis revealing significantly better performance following WBE111 at 3 months. Similarly, performance on the Corsi Block task was predicted by treatment, with simple contrast analysis revealing a trend for better performance at 3 months following WBE111. Treatment also significantly predicted systolic blood pressure (SBP) with simple contrast analysis revealing lower SBP following intervention with WBE111 in comparison to placebo. These results indicate 3 months intervention with WBE111 can facilitate better episodic memory performance in an elderly population and reduce cardiovascular risk factors over 6 months.

Antihypertensive Medication Regimen Intensity and Incident Dementia in an Older Population

OBJECTIVE

To investigate the association between antihypertensive medication regimen intensity and risk of incident dementia in an older population.

DESIGN

Prospective, longitudinal cohort study.

PARTICIPANTS/SETTING

A total of 1208 participants aged ≥78 years, free of dementia, and residing in central Stockholm at baseline (2001-2004).

MEASUREMENTS

Participants were examined at 3- and 6-year follow-up to detect incident dementia. Data were collected through face-to-face interviews, clinical examinations, and laboratory tests. Data on antihypertensive use were obtained by a physician through patient self-report, visual inspection, or medical records. Cox proportional hazards models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between time-varying antihypertensive regimen intensity and incident dementia after adjusting for potential confounders.

RESULTS

During the follow-up period, 125 participants were diagnosed with dementia. Participants who developed dementia were more likely to have vascular disease at baseline (66.4% vs 55.3%, P = .02). In fully adjusted analyses, the number of antihypertensive classes (HR 0.68, 95% CI 0.55-0.84) and total prescribed daily dose (HR 0.70, 95% CI 0.57-0.86) were significantly associated with reduced dementia risk. After considering all-cause mortality as a competing risk, the number (HR 0.75, 95% CI 0.62-0.91) and doses (HR 0.71, 95% CI 0.59-0.86) of antihypertensive classes, and the independent use of diuretics (HR 0.66, 95% CI 0.44-0.99), were significantly associated with lower dementia risk.

CONCLUSIONS

Greater intensity of antihypertensive drug use among older people may be associated with reduced incidence of dementia.

Potential Therapeutics for Vascular Cognitive Impairment and Dementia

BACKGROUND

As the human lifespan increases, the number of people affected by agerelated dementia is growing at an epidemic pace. Vascular pathology dramatically affects cognitive profiles, resulting in dementia and cognitive impairment. While vascular dementia itself constitutes a medical challenge, hypo-perfusion/vascular risk factors enhance amyloid toxicity and other memory- damaging factors and hasten Alzheimer's disease (AD) and other memory disorders' progression, as well as negatively affect treatment outcome.

METHODS

Research and online content related to vascular cognitive impairment and dementia is reviewed, specifically focusing on the potential treatment of the disorder.

RESULTS

Few therapeutic options are currently available to improve the prognosis of patients with vascular dementia and cognitive impairment, mixed AD dementia with vascular pathology, or other memory disorders. Emerging evidence, however, indicates that, like AD and other memory disorders, synaptic impairment underlies much of the memory impairment in the cognitive decline of vascular cognitive impairment and vascular dementia.

CONCLUSION

Effective rescues of the memory functions might be achieved through synaptic and memory therapeutics, targeting distinct molecular signaling pathways that support the formation of new synapses and maintaining their connections. Potential therapeutic agents include: 1) memory therapeutic agents that rescue synaptic and memory functions after the brain insults; 2) antipathologic therapeutics and an effective management of vascular risk factors; and 3) preventative therapeutic agents that achieve memory therapy through functional enhancement. These therapeutic agents are also likely to benefit patients with AD and/or other types of memory disorders.

Role of angiotensin system modulation on progression of cognitive impairment and brain MRI changes in aged hypertensive animals - A randomized double- blind pre-clinical study

Growing evidence suggests that renin angiotensin system (RAS) modulators support cognitive function in various animal models. However, little is known about their long-term effects on the brain structure in aged hypertensive animals with chronic cerebral hypoperfusion as well as which specific domains of cognition are most affected. Therefore, in the current study we examined the effects of Candesartan and Compound 21 (C21) (RAS modulators) on aspects of cognition known to diminish with advanced age and accelerate with hypertension and vascular disease. Outcome measures for sensorimotor and cognitive function were performed using a sequence of tests, all blindly conducted and assessed at baseline and after 4 and 8 weeks of chronic hypoxic hypoperfusion and treatment. Magnetic resonance imaging (MRI) was performed at the end of the 8 week study period followed by animal sacrifice and tissue collection. Both Candesartan and C21 effectively preserved cognitive function and prevented progression of vascular cognitive impairment (VCI) but only candesartan prevented loss of brain volume in aged hypertensive animals. Collectively, our findings demonstrate that delayed administration of RAS modulators effectively preserve cognitive function and prevent the development / progression of VCI in aged hypertensive animals with chronic cerebral hypoperfusion.

Strategies for dementia prevention: latest evidence and implications

Dementia is a common and debilitating syndrome with enormous impact on individuals and societies. Preventing disease onset or progression would translate to public health and societal benefits. In this review, we discuss the latest evidence on interventions that may show promise for the prevention of cognitive decline. We appraise existing evidence primarily drawn from randomized controlled trials, systematic reviews, and meta-analyses, but also highlight observational studies in humans and relevant work in model organisms. Overall, there is currently limited evidence to support a cause-effect relationship between any preventive strategy and the development or progression of dementia. However, studies to date suggest that a multifactorial intervention comprising regular exercise and healthy diet, along with the amelioration of vascular risk factors, psychosocial stress, and major depressive episodes may be most promising for the prevention of cognitive decline. We discuss the challenges, future directions, and implications of this line of research.

Treatment options and considerations for hypertensive patients to prevent dementia

INTRODUCTION

Dementia is a worldwide health concern, which leads to loss of autonomy. To date no curative treatment is available so focus on modifiable risk factors is of particular interest. Hypertension, particularly midlife high blood pressure, has been associated with an increased risk for cognitive decline and dementia including vascular dementia (VAD) and Alzheimer disease (AD). In this context, antihypertensive treatments might have a preventive effect. The objective of this review was to examine the relationship between antihypertensive therapy and cognitive decline or dementia. Areas covered: A literature search was conducted using PUBMED and the COCHRANE LIBRARY for publications from 1990 onwards mentioning cognitive decline, AD, Vad, mixed dementia, vascular cognitive impairment, hypertension and antihypertensive therapy. Thirty-nine relevant publications including 20 longitudinal studies, 10 randomized-controlled trials and 9 meta-analyses were taken into account. Expert opinion: Most observational studies have suggested a potential preventive effect of antihypertensive therapies on cognitive decline and dementia, particularly calcium channel blockers and renin-angiotensin system blockers. Randomized clinical trials and meta-analyses provided more conflicting results potentially due to methodological issues. In conclusion, antihypertensive therapies may reduce cognitive decline and incidence of dementia. Further randomized clinical trials conducted in populations at higher risk of cognitive decline, with longer periods of follow-up and cognition as the primary outcome are still needed.

Alzheimer's disease in people with Down's syndrome: the prospects for and the challenges of developing preventative treatments

People with Down's syndrome (DS) are at high risk for developing Alzheimer's disease (AD) at a relatively young age. This increased risk is not observed in people with intellectual disabilities for reasons other than DS and for this reason it is unlikely to be due to non-specific effects of having a neurodevelopmental disorder but, instead, a direct consequence of the genetics of DS (trisomy 21). Given the location of the amyloid precursor protein (APP) gene on chromosome 21, the amyloid cascade hypothesis is the dominant theory accounting for this risk, with other genetic and environmental factors modifying the age of onset and the course of the disease. Several potential therapies targeting the amyloid pathway and aiming to modify the course of AD are currently being investigated, which may also be useful for treating AD in DS. However, given that the neuropathology associated with AD starts many years before dementia manifests, any preventative treatment must start well before the onset of symptoms. To enable trials of such interventions, plasma, CSF, brain, and retinal biomarkers are being studied as proxy early diagnostic and outcome measures for AD. In this systematic review, we consider the prospects for the development of potential preventative treatments of AD in the DS population and their evaluation.

Memory Alterations and White Matter Hyperintensities in Elderly Patients With Hypertension: The ADELAHYDE-2 Study

OBJECTIVES

The longitudinal ADELAHYDE-2 study aims to identify the factors associated with cognitive impairment/decline and white matter hyperintensities burden.

METHODS

Longitudinal single-center study comprising two visits separated by approximately 7 years. A total of 131 patients completed the two visits. The primary outcome was global memory composite scale, while the secondary outcome was white matter hyperintensities (WMH/Fazekas scale) load.

RESULTS

Global memory at visit 2 (V2) was largely influenced by age, smoking status, glycated hemoglobin, and history of stroke already present at visit 1 (V1). These variables accounted for ∼51% of the memory alterations at V2. WMH at V2 was likely influenced by age, left ventricular hypertrophy, diabetes mellitus, carotid intima-media thickness, and body mass index at V1. These findings accounted for ∼37% of the WMH changes at V2. Increase in pulse wave velocity from V1 to V2 showed a trend for association with memory deterioration (adjusted estimates = 0.06; P = .067), whereas smoking and increase in systolic blood pressure (trend) were associated with an increment in WMH (adjusted estimates = 0.49; P = .047 and adjusted estimates = 0.01; P = .08, respectively). On the other hand, angiotensin-converting enzyme inhibitor/angiotensin receptor blockers and statins (trend) were likely to be protective (adjusted estimates for angiotensin-converting enzyme inhibitor/angiotensin receptor blockers = -0.49; P = .049, and adjusted estimates for statins = -0.46; P = .055).

CONCLUSIONS

Several readily identifiable factors are associated with memory deterioration and WMH, many of which are potentially modifiable. Interventions aimed to control these risk factors need to be tested prospectively in order to assess their cognitive protective value.

Association between central blood pressure, arterial stiffness, and mild cognitive impairment

Background

To determine the relationship between central blood pressure (CBP) indices and mild cognitive impairment (MCI) in adults over the age of 50.

Methods

A cross-sectional study conducted using a non-invasive SphygmoCor XCEL device. CBP indices and brachial blood pressure were measured in 50 inpatients and outpatients. MCI was assessed using the Montreal Cognitive Assessment (MoCA) instrument and by the European Consortium Criteria (ECC).

Results

Seventy-six percent of subjects had hypertension, and 52% were diagnosed as having MCI using the ECC. No significant association was found between any of the measured blood pressure variables and global cognition. A significant relationship was observed between augmentation index (AI) and abnormal clock-drawing (p = 0.04) and language (p = 0.02), and between pulse pressure amplification (PPA) and language (p = 0.03).

Conclusion

CBP indices like AI and PPA, which are markers of vascular stiffness, are associated with poor executive function and language cognitive domain deficits.

A call for comparative effectiveness research to learn whether routine clinical care decisions can protect from dementia and cognitive decline

Common diseases like diabetes, hypertension, and atrial fibrillation are probable risk factors for dementia, suggesting that their treatments may influence the risk and rate of cognitive and functional decline. Moreover, specific therapies and medications may affect long-term brain health through mechanisms that are independent of their primary indication. While surgery, benzodiazepines, and anti-cholinergic drugs may accelerate decline or even raise the risk of dementia, other medications act directly on the brain to potentially slow the pathology that underlies Alzheimer’s and other dementia. In other words, the functional and cognitive decline in vulnerable patients may be influenced by the choice of treatments for other medical conditions. Despite the importance of these questions, very little research is available. The Alzheimer’s Drug Discovery Foundation convened an advisory panel to discuss the existing evidence and to recommend strategies to accelerate the development of comparative effectiveness research on how choices in the clinical care of common chronic diseases may protect from cognitive decline and dementia.

A 10-year follow-up study of the association between calcium channel blocker use and the risk of dementia in elderly hypertensive patients

Calcium channel blockers (CCBs) are widely used for reducing blood pressure of hypertensive patients. Recent reports document the beneficial effects of CCB for preventing dementia; however, the results are controversial. We aim to evaluate the risk of developing dementia among elderly hypertensive patients treated with CCB.We designed a retrospective population-based cohort study using the records of the National Health Insurance Research Database of Taiwan dated from 2000 to 2010. The study cohort comprised 82,107 hypertensive patients of more than 60 years of age, and 4004 propensity score (PS)-matched pairs were selected according to age, sex, year of hypertension diagnosis, and baseline comorbidities. We employed a robust Cox proportional hazard model to estimate the hazard ratio (HR) of developing dementia in the PS-matched cohort.The annual incidence of dementia in the CCB-exposure group was significantly lower than that in the comparator group (3.9 vs 6.9 per 1000 person-years, P < 0.01) during the follow-up period (4.4 ± 2.5 years). Based on the PS-matched cohort, the adjusted HR of dementia in the CCB-exposure group was significantly lower than that in comparator group (HR = 0.53, 95% confidence interval: 0.39-0.72, P < 0.01). Sensitivity and subgroup analyses also confirmed similar findings.Our results provided evidence for an association between CCB use and a lower risk of developing dementia among the elderly hypertensive patients. Further studies are required to explore the causal relationship between CCB use and dementia.

Effects of early blood pressure reduction on cognitive function in patients with acute ischemic stroke

Background

The effect of early blood pressure reduction on cognitive function in patients with acute ischemic stroke remains unknown.

Aim

We tested whether antihypertensive treatment would reduce cognitive impairment in patients with acute ischemic stroke.

Methods

In the China Antihypertensive Trial in Acute Ischemic Stroke, patients with elevated blood pressure were randomly assigned to receive antihypertensive treatment or to discontinue all hypertensive medications within 48 h of onset. Cognitive function was measured by the Mini-Mental State Examination and Montreal Cognitive Assessment at 3 months after randomization in a subsample of 638 participants.

Results

Mean systolic blood pressure was reduced by 21.5 mmHg in the antihypertensive treatment group and 13.9 mmHg in the control group within 24 h after randomization ( P < 0.001). Mean systolic blood pressure was 134.9 mmHg in the antihypertensive treatment group and 141.6 mmHg in the control group at day 14 after randomization ( P < 0.001). Median Mini-Mental State Examination score was 26 and Montreal Cognitive Assessment score was 22 in both the antihypertensive treatment and control groups at 3 months. An Mini-Mental State Examination < 24 was present in 30.9% of patients in the antihypertensive treatment group compared with 29.7% in the control group (odds ratio = 1.06; 95% confidence interval 0.75–1.48; P = 0.75). Likewise, proportions of patients with Montreal Cognitive Assessment < 26 were similar between the antihypertensive treatment (70.6%) and control (70.7%) groups (odds ratio = 0.99; 95% confidence interval 0.70–1.40; P = 0.96).

Conclusions

These data indicated that early blood pressure reduction with antihypertensive medication in patients with acute ischemic stroke had no effect on cognitive impairment at 3 months.

[Neurocognitive disorders in old age : Role of pharmacotherapy in prevention and treatment]

Neurocognitive disorders (e.g. dementia, mild cognitive impairment and delirium) belong to the most frequently occurring problems in older patients. For most types of dementia as well as for mild cognitive impairment no causal pharmacotherapy is currently available. This also applies to delirium, which should be primarily treated through the identification and elimination of predisposing factors while cautiously using symptomatic therapy with psychotropic drugs. Despite intensive ongoing research efforts the search for disease-modifying drugs for the treatment of Alzheimer's dementia has not been successful. In the prevention and treatment of neurocognitive disorders, rational and evidence-based pharmacological interventions can nonetheless play an important role. Besides the limited benefits of symptomatic treatment with currently available anti-dementia drugs, this includes the strict management of medical risk factors as well as the avoidance of drugs with delirogenic and dementing side effects.

Cognitive impairment and stroke in elderly patients

We reviewed current knowledge about the interaction between stroke and vascular risk factors and the development of cognitive impairment and dementia. Stroke is increasingly recognized as an important cause of cognitive problems and has been implicated in the development of both Alzheimer’s disease and vascular dementia. The prevalence of cognitive impairment after stroke is high, and their combined effects significantly increase the cost of care and health resource utilization, with reflections on hospital readmissions and increased mortality rates. There is also substantial evidence that vascular risk factors (such as hypertension, diabetes, obesity, dyslipidemia, and tobacco smoking) are independently associated with an increased risk of cognitive decline and dementia. Thus, a successful management of these factors, as well as optimal acute stroke management, might have a great impact on the development of cognitive impairment. Notwithstanding, the pathological link between cognitive impairment, stroke, and vascular risk factors is complex and still partially unclear so that further studies are needed to better elucidate the boundaries of this relationship. Many specific pharmacological treatments, including anticholinergic drugs and antihypertensive medications, and nonpharmacological approaches, such as diet, cognitive rehabilitation, and physical activity, have been studied for patients with vascular cognitive impairment, but the optimal care is still far away. Meanwhile, according to the most recent knowledge, optimal stroke care should also include cognitive assessment in the short and long term, and great efforts should be oriented toward a multidisciplinary approach, including quality-of-life assessment and support of caregivers.

An integrative genome-wide transcriptome reveals that candesartan is neuroprotective and a candidate therapeutic for Alzheimer's disease

BACKGROUND

Alzheimer's disease is the most frequent age-related dementia, and is currently without treatment. To identify possible targets for early therapeutic intervention we focused on glutamate excitotoxicity, a major early pathogenic factor, and the effects of candesartan, an angiotensin receptor blocker of neuroprotective efficacy in cell cultures and rodent models of Alzheimer's disease. The overall goal of the study was to determine whether gene analysis of drug effects in a primary neuronal culture correlate with alterations in gene expression in Alzheimer's disease, thus providing further preclinical evidence of beneficial therapeutic effects.

METHODS

Primary neuronal cultures were treated with candesartan at neuroprotective concentrations followed by excitotoxic glutamate amounts. We performed genome-wide expression profile analysis and data evaluation by ingenuity pathway analysis and gene set enrichment analysis, compared with alterations in gene expression from two independent published datasets identified by microarray analysis of postmortem hippocampus from Alzheimer's disease patients. Preferential expression in cerebrovascular endothelial cells or neurons was analyzed by comparison to published gene expression in these cells isolated from human cortex by laser capture microdissection.

RESULTS

Candesartan prevented glutamate upregulation or downregulation of several hundred genes in our cultures. Ingenuity pathway analysis and gene set enrichment analysis revealed that inflammation, cardiovascular disease and diabetes signal transduction pathways and amyloid β metabolism were major components of the neuronal response to glutamate excitotoxicity. Further analysis showed associations of glutamate-induced changes in the expression of several hundred genes, normalized by candesartan, with similar alterations observed in hippocampus from Alzheimer's disease patients. Gene analysis of neurons and cerebrovascular endothelial cells obtained by laser capture microdissection revealed that genes up- and downregulated by glutamate were preferentially expressed in endothelial cells and neurons, respectively.

CONCLUSIONS

Our data may be interpreted as evidence of direct candesartan neuroprotection beyond its effects on blood pressure, revealing common and novel disease mechanisms that may underlie the in vitro gene alterations reported here and glutamate-induced cell injury in Alzheimer's disease. Our observations provide novel evidence for candesartan neuroprotection through early molecular mechanisms of injury in Alzheimer's disease, supporting testing this compound in controlled clinical studies in the early stages of the illness.

Challenges in the Management of Hypertension in Older Populations

The prevalence of hypertension increases with age making it a significant health concern for older persons. Aging involves a range of physiological changes such as increases in arterial stiffness, widening pulse pressure, changes in renin and aldosterone levels, decreases in renal salt excretion, declining in renal function, changes in the autonomic nervous system sensitivity and function and changes to endothelial function all of which may not only affect blood pressure but may also affect individual response to pharmacotherapy used to manage hypertension and prevent end organ damage and other complications associated with poor blood pressure control.Unlike many chronic conditions where there is limited evidence for management in older populations, there is good evidence regarding the management of hypertension in the elderly. The findings from multiple large, robust trials have provided a solid evidence-base regarding the management of hypertension in older adults, showing that reduction of blood pressure in older hypertensive populations is associated with reduced mortality and morbidity. Diuretics, agents action on the renin angiotensin system, beta blockers and calcium channel blockers have all been well studied in older populations both in view of the benefits associated with blood pressure lowering and the risks associated with associated adverse events. While all antihypertensive agents will lower blood pressure, when managing hypertension in older persons the choice of agent is dependent not only on the ability to lower blood pressure but also on the potential for harm with older persons. Understanding such potential harms in older populations is essential with older persons experiencing increased sensitivity to many of the adverse effects such as dizziness associated with the use of antihypertensive agents.Despite the wealth of evidence regarding the benefits of managing hypertension in the old and very old, a significant proportion of older individuals with hypertension have suboptimal BP control. While there is good evidence supporting blood pressure lowering in older antihypertensive agents, these have not yet been optimally translated fully into clinical guidelines and clinical practice. There appear to be considerable differences between guidelines in terms of the guidance given to clinicians. Differences in interpretation of the evidence, as well as differences in study design and populations all contribute to differences in the guideline recommendations with respect to older populations, despite the strength of the underlying scientific evidence. Differences around who is considered "old" and what BP targets and management are considered appropriate may lead to confusion among clinicians and further contribute to the evidence-practice lag.

The Alzheimer's Prevention Clinic at Weill Cornell Medical College / New York - Presbyterian Hospital: Risk Stratification and Personalized Early Intervention

In July 2013, Weill Cornell Medical College founded the first Alzheimer's Prevention Clinic (APC) in the United States, providing direct clinical care to family members of patients with Alzheimer's disease (AD) as part of the Weill Cornell Memory Disorders Program. At the APC, patients seeking to lower their AD risk undergo a comprehensive assessment, receive a personalized plan based on rapidly evolving scientific evidence, and are followed over time using validated as well as emerging clinical and research technologies. The APC approach applies the principles of pharmacogenomics, nutrigenomics and clinical precision medicine, to tailor individualized therapies for patients. Longitudinal measures currently assessed in the clinic include anthropometrics, cognition, blood biomarkers (i.e., lipid, inflammatory, metabolic, nutritional) and genetics, as well as validated, self-reported measures that enable patients to track several aspects of health-related quality of life. Patients are educated on the fundamental concepts of AD prevention via an interactive online course hosted on Alzheimer's Universe (www.AlzU.org), which also contains several activities including validated computer-based cognitive testing. The primary goal of the APC is to employ preventative measures that lower modifiable AD risk, possibly leading to a delay in onset of future symptoms. Our secondary goal is to establish a cohort of at-risk individuals who will be primed to participate in future AD prevention trials as disease-modifying agents emerge for testing at earlier stages of the AD process. The clinical services are intended to lower concern for future disease by giving patients a greater sense of control over their brain health.

Prevention studies in Alzheimer's disease: progress towards the development of new therapeutics

Alzheimer's disease (AD) is the most common form of dementia and is a major cause of disability and dependency amongst older people. AD drugs approved so far are symptomatic treatments and are not thought to affect the underlying disease process. Trials conducted with agents aiming to slow or stop disease progression in patients with AD have all failed, perhaps because they were tested too late in the disease process. Therefore, there has been a move towards prevention of AD. This paper presents an overview of trials testing pharmacological interventions for sporadic AD prevention. Those tested to date were initially developed for the treatment of AD or for the treatment of other conditions, rather than being specifically developed for AD prevention. Associated issues, such as evidence of 'proof-of-concept,' doses and safety, are discussed. A major shift has taken place in the methodology of AD prevention trials since the results of the first trials were published in the 1990s. New directions that are currently being considered in ongoing or future prevention trials are discussed, in terms of endpoints, target populations, and study design. The use of AD-specific drugs to prevent AD in high-risk individuals is currently limited by a lack of validated predictive and surrogate markers. Population approaches, such as lifestyle changes, are an alternative strategy that could be of public health interest, but may provide only limited benefits for individuals. The best chance of preventing AD may come from a combination of individual and population prevention approaches.

[Hypertension in the elderly in France: Characteristics of treatments and frequency of cognitive complaint according to the 2014 French League against Hypertension Survey]

OBJECTIVE

Describe hypertensive patients treated in 2014 in France by age and estimate the degree of cognitive complaint among subjects aged 55 and over.

METHOD

French League against Hypertension Survey (FLAHS) was conducted by mail in a representative sample of subjects aged 35 and over living in metropolitan France. Antihypertensive treatment data were obtained by self-administered questionnaire. Among the owners of a self-measurement device, blood pressure was considered to be controlled if the average of three measurements in the morning was below 135/85 mmHg. Cognitive complaint was detected by the cognitive complaint questionnaire (QPC) and analyzed by age and medical history of each subject.

RESULTS

In 2014, 30% of the population aged 35 and over (11.6 million) was treated with antihypertensive drugs. The number of treated hypertensive was: 3.45 million in the 75 and older, 2.96 million in 65-74 years, 3.24 million in 55-64 years, 1.58 million in the 45-54 years and 0.441 million in 35-44. The mono/bi/tri/quad-therapy is used in 46%/35%/14%/5% of patients. This distribution varies with age with monotherapy used in 63% of subjects under 55 years but in 40% of subjects 75 years and over. A positive QPC was noted in 11% of 55-64 years, in 21% of 75 years and older (P<0.001), in 20% of uncontrolled hypertensive patients, and in 34% of subjects with a personal history of stroke.

CONCLUSION

In France, hypertension is a disease that affects mainly the elderly. The modalities of treatment are different depending on age. Cognitive complaints are more common in uncontrolled hypertensive patients and in patients with a history of stroke.