Clinical Trials of Blood Pressure Lowering and Antihypertensive Medication: Is Cognitive Measurement State-of-the-Art?

Effects of multidomain lifestyle interventions on cognitive decline and Alzheimer's disease prevention: A literature review and future recommendations

Alzheimer's disease (AD) is a neurodegenerative disorder with an increasing incidence and currently without a cure. It is speculated that targeting multiple modifiable risk factors (MRFs) could be a beneficial strategy for the prevention of cognitive decline and AD. This study provides an overview and discusses the existing literature on multidomain lifestyle interventions in relation to cognitive decline and the prevention of AD. A literature search was performed in PubMed and Scopus, for studies published in English up to 31 May 2021. We identified nine relevant studies on the effect of multidomain lifestyle interventions on cognition (n = 8) and/or AD incidence or risk scores (n = 4). The studies included a combination of the separate intervention components diet (n = 8), physical activity (n = 9), cognitive activity (n = 6), metabolic or cardiovascular risk factor reduction strategies (n = 8), social activity (n = 2), medication (n = 2), and/or supplementation (n = 1). Global cognition was improved significantly in four of the eight studies that had global cognition as the outcome. Moreover, significant improvements were shown for cognitive domains in two of the three studies with specific cognitive domains as an outcome. No effect on AD incidence was observed, although positive results were shown for AD risk scores. The results suggest that multidomain lifestyle intervention studies may be partially effective in preventing cognitive decline. However, studies were heterogeneous and limited in follow-up. Future research on the effect of multidomain lifestyle interventions on cognitive decline and AD incidence must be conducted with a longer follow-up period.

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

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

Heart health meets cognitive health: evidence on the role of blood pressure

The enormous societal and financial burden of Alzheimer's disease and related dementias requires the identification of risk factors and pathways to reduce dementia risk. Blood pressure (BP) management and control is one promising area, in which data have been inconclusive. Accumulating evidence over the past 5 years shows the effectiveness of BP management interventions among older individuals at risk, most notably from the SPRINT-MIND trial. These findings have been coupled with longitudinal observational data. However, to date, the results do not concur on the optimal timing and target of BP lowering, and further study in diverse populations is needed. Given the long preclinical phase of dementia and data supporting the importance of BP control earlier in the lifecourse, long-term interventional and observational studies in ethnically and racially diverse populations, with novel imaging and blood-based biomarkers of neurodegeneration and vascular cognitive impairment to understand the pathophysiology, are needed to advance the field.

Aβ-accelerated neurodegeneration caused by Alzheimer's-associated ACE variant R1279Q is rescued by angiotensin system inhibition in mice

Recent genome-wide association studies identified the angiotensin-converting enzyme gene (ACE) as an Alzheimer's disease (AD) risk locus. However, the pathogenic mechanism by which ACE causes AD is unknown. Using whole-genome sequencing, we identified rare ACE coding variants in AD families and investigated one, ACE1 R1279Q, in knockin (KI) mice. Similar to AD, ACE1 was increased in neurons, but not microglia or astrocytes, of KI brains, which became elevated further with age. Angiotensin II (angII) and angII receptor AT1R signaling were also increased in KI brains. Autosomal dominant neurodegeneration and neuroinflammation occurred with aging in KI hippocampus, which were absent in the cortex and cerebellum. Female KI mice exhibited greater hippocampal electroencephalograph disruption and memory impairment compared to males. ACE variant effects were more pronounced in female KI mice, suggesting a mechanism for higher AD risk in women. Hippocampal neurodegeneration was completely rescued by treatment with brain-penetrant drugs that inhibit ACE1 and AT1R. Although ACE variant-induced neurodegeneration did not depend on β-amyloid (Aβ) pathology, amyloidosis in 5XFAD mice crossed to KI mice accelerated neurodegeneration and neuroinflammation, whereas Aβ deposition was unchanged. KI mice had normal blood pressure and cerebrovascular functions. Our findings strongly suggest that increased ACE1/angII signaling causes aging-dependent, Aβ-accelerated selective hippocampal neuron vulnerability and female susceptibility, hallmarks of AD that have hitherto been enigmatic. We conclude that repurposed brain-penetrant ACE inhibitors and AT1R blockers may protect against AD.

Associations of hypertension burden on subsequent dementia: a population-based cohort study

In this nationwide cohort study, we assessed the effects of hypertension burden and blood pressure (BP) control on dementia in different age subgroups. From the Korean National Health Insurance Service-Health Screening cohort from January 1, 2005 to December 31, 2013, we enrolled 428,976 subjects aged 40-79 years without previous diagnosis of dementia or stroke. During a mean follow-up of 7.3 ± 1.5 years, 9435 (2.2%) were diagnosed with dementia. Per 10 mmHg increase in systolic BP (SBP), risk of dementia was increased by 22% (95% confidence interval [CI] 1.15-1.30) in subjects aged 40-59 years and 8% (95% CI 1.04-1.11) in subjects aged 60-69 years. No significant associations were observed in subjects aged ≥ 70 years. Among subjects aged 40-59 years, both vascular and Alzheimer's dementia risks were increased with increasing SBP. Increasing hypertension burden (proportion of days with increased BP) was associated with higher dementia risk (hazard ratio [HR] 1.09 per 10% increase, 95% CI 1.08-1.10). Among patients with baseline SBP ≥ 140 mmHg, optimal follow-up SBP (120-139 mmHg) was associated with decreased dementia risk (HR 0.69, 95% CI 0.50-0.95). Hypertension burden was associated with higher risks of dementia. Adequate BP control was associated with lower risk of dementia in individuals aged < 70 years.

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.

Associations Between Relative Morning Blood Pressure, Cerebral Blood Flow, and Memory in Older Adults Treated and Controlled for Hypertension

[Figure: see text].

Prevention of Dementia in Patients with Atrial Fibrillation

Atrial fibrillation (AF) has been associated with an increased risk of dementia. Although there does not appear to be solid evidence that any specific treatment prevents or delays AF-associated cognitive decline, evidence is accumulating regarding the possible treatment strategies for preventing dementia. In this review, we summarize the evidence linking AF to dementia and critically appraise the proposed treatment strategies.

Atrial fibrillation (AF) is the most common form of arrhythmia in the elderly population and increases stroke risk by a factor of 4- to 5-fold. There is increasing evidence to suggest that incident AF may contribute to the development of dementia, independent of overt stroke. In particular, relatively younger patients with AF are more prone to dementia development than older patients with AF. Evidence is accumulating regarding the possible treatment strategies for preventing dementia in patients with AF. Oral anticoagulation may be effective for reducing the risk of dementia, even in patients with low stroke risks. Among oral anticoagulants, the use of non-vitamin K antagonists have been associated with a considerably decreased risk of dementia than warfarin. Moreover, successful catheter ablation for AF has also been associated with decreased dementia risk compared to medical therapy, suggesting that restoration of sinus rhythm, and not the ablation procedure itself, as the important mechanism in the prevention of AF-associated dementia. Among midlife patients with AF, there appeared to be a U-shaped association of blood pressure (BP) and a linear association of hypertension with dementia risk. A BP of 120 to 129/80 to 84 mmHg has been identified as the optimal range. Finally, integrated management of AF was associated with a reduced risk of dementia in AF patients.

Effects of intensive versus standard blood pressure control on domain-specific cognitive function: a substudy of the SPRINT randomised controlled trial

BACKGROUND

Results from the Systolic Blood Pressure Intervention Trial (SPRINT) showed that intensive control of systolic blood pressure significantly reduced the occurrence of mild cognitive impairment, but not probable dementia. We investigated the effects of intensive lowering of systolic blood pressure on specific cognitive functions in a preplanned substudy of participants from SPRINT.

METHODS

SPRINT was an open-label, multicentre, randomised controlled trial undertaken at 102 sites, including academic medical centres, Veterans Affairs medical centres, hospitals, and independent clinics, in the USA and Puerto Rico. Participants were adults aged 50 years or older with systolic blood pressure higher than 130 mm Hg, but without diabetes, history of stroke, or dementia. Participants were randomly assigned (1:1) to a systolic blood pressure goal of less than 120 mm Hg (intensive treatment) versus less than 140 mm Hg (standard treatment). All major classes of antihypertensive agents were included. A subgroup of randomly assigned participants including, but not limited to, participants enrolled in an MRI substudy was then selected for a concurrent substudy of cognitive function (target 2800 participants). Each individual was assessed with a screening cognitive test battery and an extended cognitive test battery at baseline and biennially during the planned 4-year follow-up. The primary outcomes for this substudy were standardised composite scores for memory (Logical Memory I and II, Modified Rey-Osterrieth Complex Figure [immediate recall], and Hopkins Verbal Learning Test-Revised [delayed recall]) and processing speed (Trail Making Test and Digit Symbol Coding). SPRINT was registered with ClinicalTrials.gov, NCT01206062.

FINDINGS

From Nov 23, 2010, to Dec 28, 2012, 2921 participants (mean age 68·4 years [SD 8·6], 1080 [37%] women) who had been randomly assigned in SPRINT were enrolled in the substudy (1448 received intensive treatment and 1473 received standard treatment). SPRINT was terminated early due to benefit observed in the primary outcome (composite of cardiovascular events). After a median follow-up of 4·1 years (IQR 3·7-5·8), there was no between-group difference in memory, with an annual decline in mean standardised domain score of -0·005 (95% CI -0·010 to 0·001) in the intensive treatment group and -0·001 (-0·006 to 0·005) in the standard treatment group (between-group difference -0·004, 95% CI -0·012 to 0·004; p=0·33). Mean standardised processing speed domain scores declined more in the intensive treatment group (between-group difference -0·010, 95% CI -0·017 to -0·002; p=0·02), with an annual decline of -0·025 (-0·030 to -0·019) for the intensive treatment group and -0·015 (-0·021 to 0·009) for the standard treatment group.

INTERPRETATION

Intensive treatment to lower systolic blood pressure did not result in a clinically relevant difference compared with standard treatment in memory or processing speed in a subgroup of participants from SPRINT. The effect of blood pressure lowering might not be evident in specific domains of cognitive function, but instead distributed across multiple domains.

FUNDING

National Heart, Lung, and Blood Institute, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute on Aging, National Institute of Neurological Disorders and Stroke, and the Alzheimer's Association.

Cerebral Arterial Pulsatility and Global White Matter Microstructure Impact Spatial Working Memory in Older Adults With and Without Cardiovascular Risk Factors

Aging is associated with an increased prevalence of vascular health conditions that are linked to a disruption in the cerebral vasculature and white matter microstructural organization. In people with cardiovascular risk factors, increased cerebral arterial pulsatility is associated with poorer white matter microstructural organization and cognitive functioning. This study examines the relationship among arterial pulsatility, white matter microstructural organization, and cognitive ability in a healthy adult lifespan sample. One hundred and eighty-nine adults were divided into a younger adult (<50 years, n = 97) and older adult (>50 years, n = 92). The latter were further subdivided into two subgroups with (CV+, n = 25) and without (CV−, n = 67) cardiovascular risk factors. Arterial pulsatility was measured using cardiac-gated phase-contrast flow quantification sequence and three indexes of whole-brain white matter microstructural organization [i.e., fractional anisotropy (FA), radial diffusivity (RaD), mean diffusivity (MD)] were derived from diffusion-weighted imaging (DWI). Cognitive ability was assessed using global cognitive functioning (MoCA) and a measure of working memory [sensitivity (d′) from a 2-back task]. Neither the whole group analysis nor the younger adult group showed an association between measures of arterial pulsatility, global white matter microstructural organization, and cognition. In older adults, higher MD and RaD were associated with increased arterial pulsatility and poorer working memory performance. The indirect pathway from arterial pulsatility to working memory performance via both MD and RaD measures was significant in this group. Interestingly, a comparison of CV+ and CV− subgroups showed that this mediating relationship was only evident in older adults with at least one CV risk factor. These findings are consistent with cardiovascular risk factors as underlying arterial, white matter, and cognitive decline in cognitively normal older adults.

The Effects of Lower BP Goals on Cognitive Function in the Elderly

PURPOSE OF REVIEW

To review the research on the impact of blood pressure control on prevention of cognitive impairment and dementia.

RECENT FINDINGS

Observational evidence has shown an association between hypertension and cognitive impairment. However, clinical trial results of blood pressure lowering have been inconclusive, likely due to inadequate cognitive assessment, blood pressure difference between groups, and follow-up duration. SPRINT-MIND showed a 19% reduction in mild cognitive impairment (14.6 vs 18.3 per 1000 person-years; HR, 0.81; 95% CI, 0.67-0.95), the earliest manifestation of dementia, with intensive blood pressure control. There was a statistically non-significant 17% reduction in the risk of probable dementia (HR 0.83, 95% CI 0.67-1.04). The progress of clinical trials testing the impact of blood pressure reduction on cardiovascular disease incidence has helped inform large trial testing of this intervention's impact on cognitive decline and dementia. SPRINT MIND demonstrated a positive effect of intensive blood pressure control on risk for mild cognitive impairment (MCI), and though the effect size was similar to MCI, the result was statistically non-significant possibly due to early termination of the intervention. Extension of follow-up may increase the number of new cases of dementia, producing a more conclusive result for dementia.

Cognition in the First Year After a Minor Stroke, Transient Ischemic Attack, or Mimic Event and the Role of Vascular Risk Factors

Background: Cognitive impairment following a minor stroke or transient ischemic attack (TIA) is common; however, due to diagnostic difficulties, the prevalence and underlying cause of impairment remain poorly defined. We compared cognition in patients after a minor stroke, TIA, or mimic event at three time points in the first year following the event. We examine whether cognitive impairment occurs following these events and whether this impairment differs based on the event type. Further, we measure whether these findings persist after controlling for age, education, and the presence of vascular risk factors and whether the presence of vascular risk factors, independent of event etiology, is associated with cognitive impairment. Lastly, we investigate whether increased stroke risk, as assessed by the ABCD2, is associated with reduced cognition.

Methods: Medical information, a cognitive screening test, and a measure of executive functioning were collected from 613 patients (123 minor stroke, 175 TIA, and 315 mimics) using phone interviews at three time points in the first year following the event. Linear mixed models were used to determine the effect of event type, vascular risk factors, and predicted stroke risk on cognitive performance while controlling for confounders.

Results: There was no relationship between event type and performance on either cognitive measure. When all confounders are controlled for, performance on the cognitive screening test was uniquely accounted for by the presence of heart failure, myocardial infarction, angina, and hypertension (all p < 0.047), whereas the measure of executive functioning was uniquely accounted for by the presence of hypertension and angina (all p < 0.032). Increased stroke risk also predicted performance on the cognitive screening test and the measure of executive functioning (all p < 0.002).

Conclusions: Our findings indicate that cognitive impairment following a minor stroke or TIA may be attributed to the high prevalence of chronic vascular risk factors in these patients. This highlights the importance of long-term management of vascular risk factors beyond event recovery to reduce the risk of cognitive impairment. Increased stroke risk (i.e., ABCD2 score) was also associated with reduced cognition, suggesting that it may be helpful in signaling the need for further cognitive evaluation and intervention post-event.

Reduced Cognitive Assessment Scores Among Individuals With Magnetic Resonance Imaging–Detected Vascular Brain Injury

Background and Purpose—

Little is known about the association between covert vascular brain injury and cognitive impairment in middle-aged populations. We investigated if scores on a cognitive screen were lower in individuals with higher cardiovascular risk, and those with covert vascular brain injury.

Methods—

Seven thousand five hundred forty-seven adults, aged 35 to 69 years, free of cardiovascular disease underwent a cognitive assessment using the Digital Symbol Substitution test and Montreal Cognitive Assessment, and magnetic resonance imaging (MRI) to detect covert vascular brain injury (high white matter hyperintensities, lacunar, and nonlacunar brain infarctions). Cardiovascular risk factors were quantified using the INTERHEART (A Global Study of Risk Factors for Acute Myocardial Infarction) risk score. Multivariable mixed models tested for independent determinants of reduced cognitive scores. The population attributable risk of risk factors and MRI vascular brain injury on low cognitive scores was calculated.

Results—

The mean age of participants was 58 (SD, 9) years; 55% were women. Montreal Cognitive Assessment and Digital Symbol Substitution test scores decreased significantly with increasing age ( P <0.0001), INTERHEART risk score ( P <0.0001), and among individuals with high white matter hyperintensities, nonlacunar brain infarction, and individuals with 3+ silent brain infarctions. Adjusted for age, sex, education, ethnicity covariates, Digital Symbol Substitution test was significantly lowered by 1.0 (95% CI, −1.3 to −0.7) point per 5-point cardiovascular risk score increase, 1.9 (95% CI, −3.2 to −0.6) per high white matter hyperintensities, 3.5 (95% CI, −6.4 to −0.7) per nonlacunar stroke, and 6.8 (95% CI, −11.5 to −2.2) when 3+ silent brain infarctions were present. No postsecondary education accounted for 15% (95% CI, 12–17), moderate and high levels of cardiovascular risk factors accounted for 19% (95% CI, 8–30), and MRI vascular brain injury accounted for 10% (95% CI, −3 to 22) of low test scores.

Conclusions—

Among a middle-aged community-dwelling population, scores on a cognitive screen were lower in individuals with higher cardiovascular risk factors or MRI vascular brain injury. Much of the population attributable risk of low cognitive scores can be attributed to lower educational attainment, higher cardiovascular risk factors, and MRI vascular brain injury.

Blood Pressure Control and Dementia Risk in Midlife Patients With Atrial Fibrillation

Atrial fibrillation (AF) is associated with increased risk of cognitive impairment and dementia, even with no overt stroke. Hypertension has been a potentially modifiable risk factor for dementia, especially in midlife (<70 years) individuals. We aimed to investigate the associations of blood pressure (BP) and hypertension burden with dementia risk among midlife AF patients. From the Korean National Health Insurance Service database, we enrolled 171 228 incident AF patients aged 50 to 69 years with no prior dementia from 2005 to 2016. During a mean of 6.6 years of follow-up, 9909 patients received a first-time diagnosis of dementia. U-shaped relationships were noted between systolic or diastolic BP and dementia risk: A 10 mm Hg increase or decrease in systolic BP starting from 120 mm Hg was associated with 4.4% (95% CI, 2.7%-6.0%) and 4.6% (95% CI, 0.1%-8.2%) higher dementia risk, respectively. An increase or decrease in diastolic BP starting from 80 mm Hg also increased dementia risk. In subtype analyses, Alzheimer disease increases with BP decrease whereas vascular dementia increases according to BP increase. When BP changes over time were accounted for in time-updated models, BP of 120 to 129/80 to 84 mm Hg was associated with the lowest dementia risk. Increasing hypertension burden (the proportion of days with increased BP during follow-up) was associated with higher dementia risk (hazard ratio, 1.10 per 10% increase [95% CI, 1.08-1.12]). Among midlife AF patients, there were a U-shaped association of BP and a log-linear association of hypertension burden with dementia risk. Minimizing the burden of hypertension in AF patients might help to prevent dementia.

Aortic Stiffness and Age With Cognitive Performance Decline in the ELSA-Brasil Cohort

Background Increased aortic stiffness has been associated with cognitive decline and dementia, but the results are inconsistent. This study investigated the longitudinal association of aortic stiffness and age with decreased cognitive performance in 3 cognitive tests. Methods and Results This study included 6927 participants, with a mean age of 58.8 years at baseline (2008-2010), who participated in the second wave (2012-2014) of the ELSA-Brasil (Brazilian Longitudinal Study of Adult Health) (interval between visits ranging from 2-6 years). Cognitive performance was evaluated by Memory, Phonemic, and Semantic Verbal Fluency and Trail B Tests, applied at both cohort visits. Associations with the carotid-femoral pulse wave velocity and age at baseline were investigated using linear models with mixed effects after adjusting for confounders. After all the adjustments, including for systolic blood pressure, the interaction term carotid-femoral pulse wave velocity×time proved to be statistically significant for Memory and Verbal Fluency Tests, indicating that the higher carotid-femoral pulse wave velocity at baseline was associated with a faster decline in cognitive performance in these tests between waves. The interaction term age×time was statistically significant for all cognitive tests, suggesting that increasing age at baseline was also associated with a faster decline in cognitive performance between waves. Conclusions In this relatively young cohort, and after a relatively short interval, an increased aortic stiffness at baseline was associated with a sharper decline in cognitive performances in memory and verbal fluency, regardless of systolic blood pressure levels. This study also showed that the decline in cognitive performance was faster among older individuals than among younger ones at baseline.

Effect of Intensive vs Standard Blood Pressure Control on Probable Dementia: A Randomized Clinical Trial

IMPORTANCE

There are currently no proven treatments to reduce the risk of mild cognitive impairment and dementia.

OBJECTIVE

To evaluate the effect of intensive blood pressure control on risk of dementia.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial conducted at 102 sites in the United States and Puerto Rico among adults aged 50 years or older with hypertension but without diabetes or history of stroke. Randomization began on November 8, 2010. The trial was stopped early for benefit on its primary outcome (a composite of cardiovascular events) and all-cause mortality on August 20, 2015. The final date for follow-up of cognitive outcomes was July 22, 2018.

INTERVENTIONS

Participants were randomized to a systolic blood pressure goal of either less than 120 mm Hg (intensive treatment group; n = 4678) or less than 140 mm Hg (standard treatment group; n = 4683).

MAIN OUTCOMES AND MEASURES

The primary cognitive outcome was occurrence of adjudicated probable dementia. Secondary cognitive outcomes included adjudicated mild cognitive impairment and a composite outcome of mild cognitive impairment or probable dementia.

RESULTS

Among 9361 randomized participants (mean age, 67.9 years; 3332 women [35.6%]), 8563 (91.5%) completed at least 1 follow-up cognitive assessment. The median intervention period was 3.34 years. During a total median follow-up of 5.11 years, adjudicated probable dementia occurred in 149 participants in the intensive treatment group vs 176 in the standard treatment group (7.2 vs 8.6 cases per 1000 person-years; hazard ratio [HR], 0.83; 95% CI, 0.67-1.04). Intensive BP control significantly reduced the risk of mild cognitive impairment (14.6 vs 18.3 cases per 1000 person-years; HR, 0.81; 95% CI, 0.69-0.95) and the combined rate of mild cognitive impairment or probable dementia (20.2 vs 24.1 cases per 1000 person-years; HR, 0.85; 95% CI, 0.74-0.97).

CONCLUSIONS AND RELEVANCE

Among ambulatory adults with hypertension, treating to a systolic blood pressure goal of less than 120 mm Hg compared with a goal of less than 140 mm Hg did not result in a significant reduction in the risk of probable dementia. Because of early study termination and fewer than expected cases of dementia, the study may have been underpowered for this end point.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01206062.