A Substudy Protocol of the Hypertension in the Very Elderly Trial Assessing Cognitive Decline and Dementia Incidence (HYVET-COG)

Pharmacological treatment of hypertension in people without prior cerebrovascular disease for the prevention of cognitive impairment and dementia

BACKGROUND

This is an update of a Cochrane Review first published in 2006 (McGuinness 2006), and previously updated in 2009 (McGuinness 2009). Hypertension is a risk factor for dementia. Observational studies suggest antihypertensive treatment is associated with lower incidences of cognitive impairment and dementia. There is already clear evidence to support the treatment of hypertension after stroke.

OBJECTIVES

To assess whether pharmacological treatment of hypertension can prevent cognitive impairment or dementia in people who have no history of cerebrovascular disease.

SEARCH METHODS

We searched the Specialised Register of the Cochrane Dementia and Cognitive Improvement Group, CENTRAL, MEDLINE, Embase, three other databases, as well as many trials registries and grey literature sources, most recently on 7 July 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which pharmacological interventions to treat hypertension were given for at least 12 months. We excluded trials of pharmacological interventions to lower blood pressure in non-hypertensive participants. We also excluded trials conducted solely in people with stroke.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information. We collected information regarding incidence of dementia, cognitive decline, change in blood pressure, adverse effects and quality of life. We assessed the certainty of evidence using GRADE.

MAIN RESULTS

We included 12 studies, totaling 30,412 participants, in this review. Eight studies compared active treatment with placebo. Of the four non-placebo-controlled studies, two compared intensive versus standard blood pressure reduction. The two final included studies compared different classes of antihypertensive drug. Study durations varied from one to five years. The combined result of four placebo-controlled trials that reported incident dementia indicated no evidence of a difference in the risk of dementia between the antihypertensive treatment group and the placebo group (236/7767 versus 259/7660, odds ratio (OR) 0.89, 95% confidence interval (CI) 0.72 to 1.09; very low certainty evidence, downgraded due to study limitations and indirectness). The combined results from five placebo-controlled trials that reported change in Mini-Mental State Examination (MMSE) may indicate a modest benefit from antihypertensive treatment (mean difference (MD) 0.20, 95% CI 0.10 to 0.29; very low certainty evidence, downgraded due to study limitations, indirectness and imprecision). The certainty of evidence for both cognitive outcomes was downgraded on the basis of study limitations and indirectness. Study durations were too short, overall, to expect a significant difference in dementia rates between groups. Dementia and cognitive decline were secondary outcomes for most studies. Additional sources of bias include: the use of antihypertensive medication by the placebo group in the placebo-controlled trials; failure to reach recruitment targets; and early termination of studies on safety grounds. Meta-analysis of the placebo-controlled trials reporting results found a mean change in systolic blood pressure of -9.25 mmHg (95% CI -9.73, -8.78) between treatment (n = 8973) and placebo (n = 8820) groups, and a mean change in diastolic blood pressure of -2.47 mmHg (95% CI -2.70, -2.24) between treatment (n = 7700) and placebo (n = 7509) groups (both low certainty evidence downgraded on the basis of study limitations and inconsistency). Three trials - SHEP 1991, LOMIR MCT IL 1996 and MRC 1996 - reported more withdrawals due to adverse events in active treatment groups than placebo groups. Participants on active treatment in Syst Eur 1998 were less likely to discontinue treatment due to side effects, and participants on active treatment in HYVET 2008 reported fewer 'serious adverse events' than in the placebo group. There was no evidence of a difference in withdrawals rates between groups in SCOPE 2003, and results were unclear for Perez Stable 2000 and Zhang 2018. Heterogeneity precluded meta-analysis. Five of the placebo-controlled trials provided quality of life (QOL) data. Heterogeneity again precluded meta-analysis. SHEP 1991, Syst Eur 1998 and HYVET 2008 reported no evidence of a difference in QOL measures between active treatment and placebo groups over time. The SCOPE 2003 sub-study (Degl'Innocenti 2004) showed a smaller drop in QOL measures in the active treatment compared to the placebo group. LOMIR MCT IL 1996 reported an improvement in a QOL measure at twelve months in one active treatment group and deterioration in another.

AUTHORS' CONCLUSIONS

High certainty randomised controlled trial evidence regarding the effect of hypertension treatment on dementia and cognitive decline does not yet exist. The studies included in this review provide low certainty evidence (downgraded primarily due to study limitations and indirectness) that pharmacological treatment of hypertension, in people without prior cerebrovascular disease, leads to less cognitive decline compared to controls. This difference is below the level considered clinically significant. The studies included in this review also provide very low certainty evidence that pharmacological treatment of hypertension, in people without prior cerebrovascular disease, prevents dementia.

Evaluation of frequency of occurrence of cognitive impairment in the course of arterial hypertension in an elderly population

BACKGROUND

Dementia is a very serious problem with regard to geriatric population. In the population over the age of 80 the prevalence of dementia varies by up to 20%. It is very important to answer the question - are arterial hypertension and its duration associated with cognitive performance?

METHODS

One hundred and sixty people were qualified for participation in the study, women and men, diagnosed with arterial hypertension. The patients were divided into two pairs of groups. The first pair was group 1, patients with hypertension over the age of 85 and group 2, patients with hypertension aged 75-85. The second pair was group I, patients with up to 10 years of arterial hypertension and group II, patients with over 10 years of arterial hypertension. In the study, the Mini-Mental State Examination (MMSE) was used. Interpretation of impairment depended on the obtained numerical value.

RESULTS

In the tested group of patients, for individual correlations it was found that age is the independent variable which significantly affects the MMSE score. It was found that the time of duration of arterial hypertension did not have impact on the MMSE.

CONCLUSION

Cognitive functions evaluated through the MMSE were correct for the entire population. The length of the course of arterial hypertension did not have a significant adverse impact on cognitive functions and on the achieved MMSE result. Significant impact of age on the lowering of MMSE results and impairment of cognitive functions was shown.

Association of late-life changes in blood pressure and cognitive status

Background

Disagreement exists on the association between changes in blood pressure and cognitive impairment. We aimed to examine whether 4-year changes in systolic and diastolic blood pressure (SBP and DBP) are associated with cognitive status in a representative sample of older men and women.

Methods

Analysis of longitudinal data from 854 participants of a population-based German sample (aged 60–87 years) was performed with standard cognitive screening and blood pressure measurements. Effects of changes in SBP and DBP (10 mmHg and 5 mmHg respectively as unit of regression effect measure) on cognitive status were evaluated using non-parametric and linear regression modeling.

Results

No clear associations were seen between changes in SBP or in DBP and cognitive scores. Small effects were found after stratification for sex and hypertension awareness. Specifically, larger decreases in SBP were associated with higher cognitive scores in those men aware of their hypertension (10 mmHg decrease in SBP, β = −0.26, 95% CI: −0.51 to −0.02) and men with controlled hypertension (10 mmHg decrease in SBP, β = −0.44, 95% CI: −0.92 to −0.03). Additionally larger increases in DBP were associated with higher cognitive scores in men with controlled hypertension (5 mmHg increase in DBP, β = 0.67, 95% CI: 0.19–1.15). For women aware of their hypertension, larger decreases in DBP were associated with higher cognitive scores (5 mmHg decrease in DBP, β = −0.26; 95%CI: −0.51 to −0.01).

Conclusions

Changes in blood pressure were only weakly associated with cognitive status. Specifically, decreases in SBP were associated with higher cognitive scores in men aware of their hypertension and especially those that were medically controlled.

The relationship between blood pressure and cognitive function

The relationship between blood pressure (BP) and cognitive outcomes in elderly adults has implications for global health care. Both hypertension and hypotension affect brain perfusion and worsen cognitive outcomes. The presence of hypertension and other vascular risk factors has been associated with decreased performance in executive function and attention tests. Cerebrovascular reserve has emerged as a potential biomarker for monitoring pressure-perfusion-cognition relationships. A decline in vascular reserve capacity can lead to impaired neurovascular coupling and decreased cognitive ability. Endothelial dysfunction, microvascular disease, and mascrovascular disease in midlife could also have an important role in the manifestations and severity of multiple medical conditions underlying cognitive decline late in life. However, questions remain about the role of antihypertensive therapies for long-term prevention of cognitive decline. In this Review, we address the underlying pathophysiology and the existing evidence supporting the role of vascular factors in late-life cognitive decline.

Hypertension, dementia, and antihypertensive treatment: implications for the very elderly

A wealth of longitudinal epidemiologic evidence links high blood pressure or hypertension to cognitive decline and incident dementia. Some (but not all) studies have suggested that antihypertensive treatment is beneficial, reducing risk of decline and dementia. There are plausible mechanisms to support the possibility that hypertension may increase the risk of dementia. There is also evidence suggesting that the two dementia types thought to be most common, Alzheimer's disease and vascular dementia, have overlapping risk factors. Seven placebo-controlled trials of antihypertensive treatment have assessed cognitive function, incident dementia, or both, with mixed outcomes. The Hypertension in the Very Elderly Trial (HYVET), despite showing reductions in mortality and stroke with active treatment, found no significant reduction of incident dementia, although the trial was stopped early. Meta-analyses used to explore this area further are inconclusive, and comparative trials are now required.

Modelling cognitive decline in the Hypertension in the Very Elderly Trial [HYVET] and proposed risk tables for population use

Introduction

Although, on average, cognition declines with age, cognition in older adults is a dynamic process. Hypertension is associated with greater decline in cognition with age, but whether treatment of hypertension affects this is uncertain. Here, we modelled dynamics of cognition in relation to the treatment of hypertension, to see if treatment effects might better be discerned by a model that included baseline measures of cognition and consequent mortality

Methodology/Principal Findings

This is a secondary analysis of the Hypertension in the Very Elderly Trial (HYVET), a double blind, placebo controlled trial of indapamide, with or without perindopril, in people aged 80+ years at enrollment. Cognitive states were defined in relation to errors on the Mini-Mental State Examination, with more errors signifying worse cognition. Change in cognitive state was evaluated using a dynamic model of cognitive transition. In the model, the probabilities of transitions between cognitive states is represented by a Poisson distribution, with the Poisson mean dependent on the baseline cognitive state.

The dynamic model of cognitive transition was good (R² = 0.74) both for those on placebo and (0.86) for those on active treatment. The probability of maintaining cognitive function, based on baseline function, was slightly higher in the actively treated group (e.g., for those with the fewest baseline errors, the chance of staying in that state was 63% for those on treatment, compared with 60% for those on placebo). Outcomes at two and four years could be predicted based on the initial state and treatment.

Conclusions/Significance

A dynamic model of cognition that allows all outcomes (cognitive worsening, stability improvement or death) to be categorized simultaneously detected small but consistent differences between treatment and control groups (in favour of treatment) amongst very elderly people treated for hypertension. The model showed good fit, and suggests that most change in cognition in very elderly people is small, and depends on their baseline state and on treatment. Additional work is needed to understand whether this modelling approach is well suited to the valuation of small effects, especially in the face of mortality differences between treatment groups.

Trial Registration

ClinicalTrials.gov NCT0012281

Cardiovascular and biochemical risk factors for incident dementia in the Hypertension in the Very Elderly Trial

OBJECTIVES

Several cardiovascular and biochemical factors including hypertension have been associated with cognitive decline and dementia, although both epidemiological and intervention evidence is mixed with the majority of studies examining those in midlife or younger elderly and the recent Hypertension in the Very Elderly Trial showing no significant association between blood pressure lowering and incident dementia. It has also been suggested that risk factors may differ in the very elderly. The aim of these analyses was to examine the impact of baseline cardiovascular and biochemical factors upon incident dementia and cognitive decline in a very elderly hypertensive group.

METHODS

Participants of the Hypertension in the Very Elderly Trial were aged at least 80 years and hypertensive. Cognitive function was assessed at baseline and annually with diagnostic information collected for dementia and relationships between baseline total and high-density lipoprotein cholesterol, creatinine, glucose, haemoglobin, heart failure, atrial fibrillation, diabetes, previous stroke and later dementia/cognitive decline were examined.

RESULTS

There were 3336 participants with longitudinal cognitive function data. In multivariate analyses higher creatinine was associated with a lower risk of incident dementia and cognitive decline. Higher total and lower high-density lipoprotein cholesterol were associated with lower risk of cognitive decline. Other variables were not significant.

CONCLUSIONS

In very elderly hypertensive patients heart failure, diabetes, atrial fibrillation, prior stroke, glucose and haemoglobin levels did not demonstrate a relationship with cognitive decline or dementia. Higher creatinine (excluding moderate renal impairment) was associated with a lower risk of dementia and cognitive decline. The findings for total and high-density lipoprotein cholesterol add to the varied literature in this area and together these findings may add weight to the suggestion that risk factor profiles differ in the very elderly.

A systematic review of community-based health interventions on depression for older adults with heart disease

PURPOSE

This systematic review examined the effectiveness of community-based heart-health interventions on depression outcomes among homebound elderly (64 years and older) with heart disease.

DESIGN AND METHODS

A comprehensive literature search and meta analysis was performed to evaluate randomized controlled trials examining outpatient or home-based interventions. Methodological quality was assessed by standard criteria developed by the Cochrane Collaborative Initiative.

RESULTS

Fifteen studies met our inclusion criteria and all measured depression outcomes. Studies differed in scope and methodological rigor and sample sizes varied widely. Problems in treatment fidelity and masking of group assignment were noted. Great variability was found in depression outcomes due to the differences in methodology and intervention. Five studies reported significant treatment effect on depression; three of those employed home-based interventions and two were outpatient-clinic interventions. Ten studies were included in the meta analysis and the effect sizes (ESs) ranged from -0.39 (in favor of control group) to 0.65 (in favor of treatment group). The mean weighted ES was 0.11 and six studies showed positive ESs.

IMPLICATIONS

Mixed evidence for community-based heart disease interventions on depression outcomes was found. Future research should include sub-analysis of ESs of interventions on depression outcomes by different demographic characteristics of the study sample, common depression outcome measures, and different follow-up periods.

Blood pressure lowering in patients without prior cerebrovascular disease for prevention of cognitive impairment and dementia

BACKGROUND

This is an update of a previous review (McGuinness 2006).Hypertension and cognitive impairment are prevalent in older people. Hypertension is a direct risk factor for vascular dementia (VaD) and recent studies have suggested hypertension impacts upon prevalence of Alzheimer's disease (AD). Therefore does treatment of hypertension prevent cognitive decline?

OBJECTIVES

To assess the effects of blood pressure lowering treatments for the prevention of dementia and cognitive decline in patients with hypertension but no history of cerebrovascular disease.

SEARCH STRATEGY

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group, The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS as well as many trials databases and grey literature sources were searched on 13 February 2008 using the terms: hypertens$ OR anti-hypertens$.

SELECTION CRITERIA

Randomized, double-blind, placebo controlled trials in which pharmacological or non-pharmacological interventions to lower blood pressure were given for at least six months.

DATA COLLECTION AND ANALYSIS

Two independent reviewers assessed trial quality and extracted data. The following outcomes were assessed: incidence of dementia, cognitive change from baseline, blood pressure level, incidence and severity of side effects and quality of life.

MAIN RESULTS

Four trials including 15,936 hypertensive subjects were identified. Average age was 75.4 years. Mean blood pressure at entry across the studies was 171/86 mmHg. The combined result of the four trials reporting incidence of dementia indicated no significant difference between treatment and placebo (236/7767 versus 259/7660, Odds Ratio (OR) = 0.89, 95% CI 0.74, 1.07) and there was considerable heterogeneity between the trials. The combined results from the three trials reporting change in Mini Mental State Examination (MMSE) did not indicate a benefit from treatment (Weighted Mean Difference (WMD) = 0.42, 95% CI 0.30, 0.53). Both systolic and diastolic blood pressure levels were reduced significantly in the three trials assessing this outcome (WMD = -10.22, 95% CI -10.78, -9.66 for systolic blood pressure, WMD = -4.28, 95% CI -4.58, -3.98 for diastolic blood pressure). Three trials reported adverse effects requiring discontinuation of treatment and the combined results indicated no significant difference (OR = 1.01, 95% CI 0.92, 1.11). When analysed separately, however, more patients on placebo in Syst Eur 1997 were likely to discontinue treatment due to side effects; the converse was true in SHEP 1991. Quality of life data could not be analysed in the four studies. Analysis of the included studies in this review was problematic as many of the control subjects received antihypertensive treatment because their blood pressures exceeded pre-set values. In most cases the study became a comparison between the study drug against a usual antihypertensive regimen.

AUTHORS' CONCLUSIONS

There is no convincing evidence from the trials identified that blood pressure lowering in late-life prevents the development of dementia or cognitive impairment in hypertensive patients with no apparent prior cerebrovascular disease. There were significant problems identified with analysing the data, however, due to the number of patients lost to follow-up and the number of placebo patients who received active treatment. This introduced bias. More robust results may be obtained by conducting a meta-analysis using individual patient data.

Sociodemographic and lifestyle risk factors for incident dementia and cognitive decline in the HYVET

INTRODUCTION

previous studies have suggested that smoking, living alone and having a high body mass index may increase risk of developing dementia whereas a normal body mass index, having received education and moderate alcohol consumption may decrease risk. Dementia risk also increases with age and is thought to be higher in hypertensives.

METHOD

we used data collected in the Hypertension in the Very Elderly Trial (HYVET), and cognitive function was assessed using the Mini-Mental State Examination (MMSE) at baseline and annually. Participants with a fall in MMSE to <24 or with a fall of 3 points in any 1 year were investigated further. The association of baseline sociodemographic, medical and lifestyle factors with incident dementia or decline in MMSE scores was assessed by regression models.

RESULTS

incident dementia occurred in 263 of 3,336 participants over a mean follow-up of 2 years. In multivariate analyses, being underweight, BMI < 18.5 (HR 1.90, 95% CI 1.06-3.39) or obese, BMI >30 (HR 1.84, 95% CI 1.24-2.72), increased risk of incident dementia as did piracetam use (HR 2.72, 95% CI 1.60-4.63). Receiving formal education was associated with a reduced risk (HR 0.59, 95% CI 0.45-0.78). There was no association with smoking, alcohol and gender. Similar results were found when examining mean annual change in the MMSE score.

DISCUSSION

our results for BMI and education agree with those from other studies. The increased risk associated with piracetam may reflect awareness of memory problems before any diagnosis of dementia has been made. Trial participants may be healthier than the general population and further studies in the general population are required.

Baseline characteristics of participants in the Hypertension in the Very Elderly Trial (HYVET)

The Hypertension in the Very Elderly Trial (HYVET) is a randomized double-blind trial of active antihypertensive treatment (indapamide 1.5 mg sustained release +/-2-4 mg perindopril) vs placebo in participants over the age of 80 years with a systolic blood pressure (SBP) of 160-199 mmHg during a placebo run-in period plus a diastolic blood pressure (DBP) of<110 mmHg. The trial has completed with 3845 subjects randomized and we report the baseline characteristics. The participants were a healthy group. The numbers smoking, drinking alcohol and having previous cardiovascular events were low, and their hypertensive status was not usually associated with the metabolic syndrome; 1.0% of the whole group had a total cholesterol over 8.0 mmol/l, 1.1% a blood sugar over 11.1 mmol/l (irrespective of anti-diabetic treatment) and 1.7% a serum urate over 460 micromol/l (women) and 0.6% over 520 micromol/l (men). A serum creatinine over 150 micromol/l excluded participants from the trial. The gender differences and age comparisons were as expected but the women had higher average total and high-density-lipoprotein-cholesterol blood concentrations. Those with prior cardiovascular disease had an excess of the known cardiovascular risk factors. The baseline characteristics provide a basis for further understanding of the HYVET results, which have been published recently.

Vascular risk factors and cognitive function among 3763 participants in the Hypertension in the Very Elderly Trial (HYVET): a cross-sectional analysis

BACKGROUND

It is well known that the global population is aging and that those over the age of 80 are the fastest growing part of this expansion. Also known is that prevalence of hypertension and cognitive decline both increase with increasing age.

METHOD

The Hypertension in the Very Elderly Trial (HYVET) was a double blind placebo-controlled trial of antihypertensive treatment (indapamide SR 1.5 mg +/- perindopril 2-4 mg) and recruited only those hypertensives who were aged 80 or over and were without a diagnosis of dementia at baseline. Systolic blood pressure had to be in the range 160-199 mmHg and diastolic pressure <110 mmHg. Cognitive function was assessed at baseline using the Mini-mental State Examination prior to randomization into the trial. Also collected at baseline was information relating to sociodemographic, clinical, cardiovascular and biochemical factors which may impact upon cognitive function. This paper reports on the baseline cognitive function data from the HYVET trial and its relationship to these factors.

RESULTS

The mean age of the 3763 HYVET participants who had full cognitive function data at baseline was 83.6 years; 60 percent were female. The median MMSE score at baseline was 26 and, in multivariate analyses, higher at younger age, with male gender, higher educational level, having higher creatinine, higher total cholesterol and lower high-density lipoprotein cholesterol.

CONCLUSIONS

This is the first such study to examine a large number of very elderly hypertensives and it shows some similar patterns to those seen in younger elderly groups.

Optimal treatment of hypertension in the elderly: a Korean perspective

With the progression of the aging population, common diseases of the elderly have become the center of attention in most developed countries. Hypertension is one of the most common morbid conditions in the elderly and has a great impact on their health status because it is the main risk factor of cardiovascular and cerebrovascular diseases. However, a considerable amount of uncertainty remains regarding hypertension in the elderly, such as the benefits of hypertension control in oldest-old populations, the optimal level of blood pressure control, and the efficacy of antihypertensive drugs for the prevention of cognitive dysfunction. While there are many controversial issues concerning the optimal management of hypertension in the elderly, the number of elderly hypertensive patients that require treatment is expected to increase due to the aging population. As a result, knowledge regarding the mechanisms of hypertension in the elderly and specific consideration in managing hypertensive elderly patients are needed to improve the clinical outcome. Furthermore, new therapeutic interventions that are aimed at attenuating age-related vascular changes should be investigated, because hypertension in the elderly, especially isolated systolic hypertension has specific characteristics of increased arterial stiffness in most cases.

Effects of hypertension therapy based on eprosartan on systolic arterial blood pressure and cognitive function: primary results of the Observational Study on Cognitive function And Systolic Blood Pressure Reduction open-label study

BACKGROUND

Recent studies have indicated a relationship between hypertension and cognitive function but therapeutic trials of antihypertensive therapy on the prevention of cognitive disorders have produced controversial findings.

METHODS

The Observational Study on Cognitive function And Systolic Blood Pressure Reduction is an open-label trial in 28 countries designed to evaluate the impact of eprosartan-based therapy on cognitive function. The Mini-Mental State Examination was used as a global tool for the comprehensive assessment of cognitive function, with an intention to treat a cohort of 25 745 hypertensive patients aged at least 50 years during a follow-up interval of 6 months. Blood pressure therapy was initiated with eprosartan 600 mg/day with provision for additional medication to be introduced after 1 month in patients with insufficient blood pressure response.

RESULTS

Use of eprosartan, either as monotherapy or in combination regimens, was associated with a substantial reduction in arterial blood pressure from 161.9/93.1 mmHg at baseline to 136.1/80.8 mmHg at 6 months (P < 0.0001). The overall mean Mini-Mental State Examination score at completion of follow-up was 27.9 +/- 2.9 compared with 27.1 +/- 3.4 at baseline (P < 0.0001). A significant correlation was shown between the mean absolute response of Mini-Mental State Examination and the magnitude of systolic blood pressure reduction. At the end of the study, patients with systolic blood pressure less than 140 mmHg had a larger improvement in Mini-Mental State Examination [0.88 +/- 0.01 (SEM)] than those with systolic blood pressure between 140 and 159 mmHg [0.69 +/- 0.02 (SEM); P < 0.001], or than those with systolic blood pressure of at least 160 mmHg [0.38 +/- 0.05 (SEM); P < 0.0001]. Furthermore, cognitive decline was demonstrated in multiple linear regression to be independently associated with age [odds ratio 1.19 (1.14; 1.25)], Mini-Mental State Examination at baseline [odds ratio 1.19 (1.14; 1.25)], systolic blood pressure at baseline [odds ratio 1.20 (1.13; 1.27)] and systolic blood pressure reduction [odds ratio 0.77 (0.73; 0.82)].

CONCLUSION

The results of the Observational Study on Cognitive function And Systolic Blood Pressure Reduction are supportive of the proposition that antihypertensive therapy based on drugs that target the renin-angiotensin system is associated with preservation of cognitive function.

Antihypertensive treatment in elderly hypertensives without a history of stroke and the risk of cognitive disorders

OBJECTIVES

The role of the antihypertensive therapy in preventing cognitive disorders in elderly persons without a history of stroke is a matter of debate. This review focuses on the pathogenesis of the cognitive disorders in elderly hypertensives and on the risk factors of their occurrence.

METHODS

Relevant papers were identified by searches in PubMed from 1946 until October 2007, using the key words 'vascular risk factors', 'vascular cognitive impairment', 'vascular dementia', 'neuroimaging in hypertension' and 'antihypertensive treatment'.

RESULTS

Blood pressure lowering in elderly patients with long-standing hypertension below a certain critical level may increase the risk of cerebral hypoperfusion and cognitive decline, particularly in cases with additional vascular risk factors. Cerebral white matter lesions have been found in the majority of elderly hypertensives. They have been shown to correlate with cognitive disorders.

CONCLUSIONS

Appropriate neuropsychological assessment and follow-up of the cognitive functions could be considered with the aim to individualize the antihypertensive therapy and slow down cognitive decline. Prospective studies are needed to confirm such a treatment strategy.

Management of hypertension and cerebrovascular disease in the elderly

Cardiovascular disease and stroke disproportionately affect the elderly. The risk for stroke and transient ischemic attack increases exponentially with age. Blood pressure is a potent modifiable target for reducing the risk for stroke in the elderly. In elderly patients with isolated systolic hypertension and those with intracranial atherosclerotic disease, blood pressure lowering has consistently been shown to be well tolerated and effective in reducing the risk for stroke and its complications. Evidence suggests that ambulatory blood pressure monitoring may provide a more sensitive means of detecting patients at risk and monitoring therapeutic effect. Agents that modify the renin-angiotensin system, particularly angiotensin receptor blockers, may confer additional benefit in stroke protection beyond blood pressure lowering. Several clinical trials currently in progress promise to provide guidance regarding the optimal choice of agent and degree of blood pressure lowering for prevention of stroke and cognitive decline in elderly patients.

Incident dementia and blood pressure lowering in the Hypertension in the Very Elderly Trial cognitive function assessment (HYVET-COG): a double-blind, placebo controlled trial

BACKGROUND

Observational epidemiological studies have shown a positive association between hypertension and risk of incident dementia; however, the effects of antihypertensive therapy on cognitive function in controlled trials have been conflicting, and meta-analyses of the trials have not provided clear evidence of whether antihypertensive treatment reduces dementia incidence. The Hypertension in the Very Elderly trial (HYVET) was designed to assess the risks and benefits of treatment of hypertension in elderly patients and included an assessment of cognitive function.

METHODS

Patients with hypertension (systolic pressure 160-200 mm Hg; diastolic pressure <110 mm Hg) who were aged 80 years or older were enrolled in this double-blind, placebo-controlled trial. Participants were randomly assigned to receive 1.5 mg slow release indapamide, with the option of 2-4 mg perindopril, or placebo. The target systolic blood pressure was 150 mm Hg; the target diastolic blood pressure was 80 mm Hg. Participants had no clinical diagnosis of dementia at baseline, and cognitive function was assessed at baseline and annually with the mini-mental state examination (MMSE). Possible cases of incident dementia (a fall in the MMSE score to <24 points or a drop of three points in 1 year) were assessed by standard diagnostic criteria and expert review. The trial was stopped in 2007 at the second interim analysis after treatment resulted in a reduction in stroke and total mortality. Analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00122811.

FINDINGS

3336 HYVET participants had at least one follow-up assessment (mean 2.2 years) and were included: 1687 participants were randomly assigned to the treatment group and 1649 to the placebo group. Only five reports of adverse effects were attributed to the medication: three in the placebo group and two in the treatment group. The mean decrease in systolic blood pressure between the treatment and placebo groups at 2 years was systolic -15 mm Hg, p<0.0001; and diastolic -5.9 mm Hg, p<0.0001. There were 263 incident cases of dementia. The rates of incident dementia were 38 per 1000 patient-years in the placebo group and 33 per 1000 patient-years in the treatment group. There was no significant difference between treatment and placebo groups (hazard ratio [HR] 0.86, 95% CI 0.67-1.09); however, when these data were combined in a meta-analysis with other placebo-controlled trials of antihypertensive treatment, the combined risk ratio favoured treatment (HR 0.87, 0.76-1.00, p=0.045).

INTERPRETATION

Antihypertensive treatment in elderly patients does not statistically reduce incidence of dementia. This negative finding might have been due to the short follow-up, owing to the early termination of the trial, or the modest effect of treatment. Nevertheless, the HYVET findings, when included in a meta-analysis, might support antihypertensive treatment to reduce incident dementia.

Action on vascular risk factors: importance of blood pressure and lipid lowering in stroke secondary prevention

INTRODUCTION

Secondary stroke prevention comprises a broad spectrum of therapeutic actions that includes the appropriate management of risk factors and the action on blood pressure and serum lipids that are of great importance to decrease stroke recurrences.

METHODS

We conducted a review of the published studies analyzing the relevance of the treatment of blood pressure and serum lipids, with special attention to recent findings of clinical trials and current guidelines on stroke secondary prevention.

RESULTS

The relationship between blood pressure and stroke has been widely demonstrated; however, the role of serum lipids has been discussed for a long time. Recent results from epidemiological studies and clinical trials have demonstrated its role as modifiable risk factor for stroke. Blood pressure and lipid lowering are associated with significant reductions in recurrent strokes as well as in other vascular events in transient ischemic attack (TIA) or stroke patients. The PROGRESS and MOSES trials suggest that diuretics, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers could confer additional benefits in stroke patients, and the SPARCL study did so for statins. These drugs are not only efficacious in the reduction of stroke recurrences, but also in other cardiovascular events.

CONCLUSIONS

Blood pressure and serum lipids are two important and modifiable vascular risk factors that should be taken into consideration when planning secondary stroke prevention measures. This approach should include hypotensive drugs (mainly the combination of diuretics and ACE inhibitors) with the objective to maintain normal blood pressure, avoiding levels >130/80 mm Hg in all stroke patients, and statins (atorvastatin 80 mg) in patients with noncardioembolic TIA or stroke.

Rationale, design and methods of the OSCAR study: observational study on cognitive function and systolic blood pressure reduction in hypertensive patients

Data from several recent clinical trials have suggested a beneficial effect of antihypertensive medications on preservation of cognitive function. Eprosartan, an angiotensin type-1 receptor antagonist (ARA) with dual action on both pre- and postsynaptic angiotensin type 1 receptors, may be effective in the control of SBP and the prevention of cognitive decline. The OSCAR (Observational Study on Cognitive function And SBP Reduction) study is an international longitudinal observational study with a duration of 6 months intended to examine the impact of the ARA eprosartan on cognitive function (assessed using the Mini-Mental State Examination [MMSE]) and control of systolic blood pressure (SBP) in a large international population of hypertensive patients managed in a standard primary care setting. A total of 100,000 hypertensive patients, aged >or=50 years and with SBP of >140 mmHg will be recruited by more than 20 000 primary care physicians in 27 countries. These patients will receive eprosartan 600 mg once a day for 6 months. The MMSE, a globally validated cognitive screening test, will be performed at baseline, and after 6 months of treatment. After the first month of monotherapy, eprosartan treatment may, at the absolute discretion of individual investigators, be supplemented with other antihypertensive medications for the remainder of the study. The primary outcome indices are the mean relative change in MMSE score and the absolute change from baseline in SBP in the study population as a whole and in subsets of patients according to various factors among them: ethnicity, comorbidities (i.e. target organ damage, diabetes), baseline cognitive level and baseline blood pressure level. The secondary objectives are to identify factors influencing SBP and MMSE changes. The OSCAR trial is the first international observational study focusing on MMSE in a wide international cohort of hypertensive patients. The results are expected in 2007.

Is it Time for a Cardiovascular Primary Prevention Trial in the Elderly?

Background and Purpose— Statins have been shown conclusively to reduce the risk of cardiovascular events in subjects with clinical cardiovascular disease or diabetes aged 65 to 80 years of age. However, few data are available for primary prevention of cardiovascular disease in those aged ≥70 years.

Summary of Review— A moderate-dose statin was of little benefit in a population aged 70 to 82 years when given for 3 years in the setting of suboptimally treated blood pressure. More evidence supports the use of blood pressure–lowering medications, but few data are available regarding the appropriate blood pressure target and most effective agents in the elderly. Some evidence also suggests that the elderly could experience higher mortality with antihypertensive treatment. These findings, along with greater safety concerns and an increasing number of competing risks and medical conditions with advancing age, make it imperative to carefully evaluate the risk/benefit balance from treating hypercholesterolemia and hypertension in persons aged ≥70 years.

Conclusions— We propose a 5-year 2×2 factorial trial of primary prevention in the elderly that will (1) evaluate whether statin therapy will reduce the risk of cardiovascular events when added to the treatment of hypertension to achieve a blood pressure <140/90 mm Hg in most patients and (2) determine the most appropriate blood pressure regimen for the prevention of cardiovascular and renal events.