Microalbuminuria, peripheral artery disease, and cognitive function

Research on cognitive impairment and potential risk factors in peritoneal dialysis patients: An observational study

The objective of this study is to investigate the associated risk factors and their effects on cognitive impairment (CI) in patients undergoing peritoneal dialysis. A retrospective analysis was conducted on the basic information of 268 patients who underwent continuous ambulatory peritoneal dialysis (CAPD) at our hospital from January 2020 to September 2023. Cognitive function was assessed using the Montreal Cognitive Assessment Scale during their subsequent dialysis visits. Participants were categorized into a CI group and a cognitively normal group. Blood and other biological samples were collected for relevant biomarker analysis. Subsequently, we analyzed and compared the factors influencing CI between the 2 groups. The prevalence of CI among CAPD patients was 58.2%. Compared to the cognitively normal group, the CI group had a higher prevalence of alcohol consumption, lower levels of education, and reduced serum uric acid levels (P < .05). There was also a higher incidence of autoimmune diseases such as systemic lupus erythematosus in the CI group (P < .05). In terms of dialysis efficacy, the residual kidney Kt/V and residual kidney Ccr were significantly lower in the CI group compared to the cognitively normal group. In blood parameters, the CI group showed elevated total cholesterol levels and lower serum calcium concentrations (P < .05). Logistic regression analysis identified male gender, older age, lower educational attainment, hypercholesterolemia, and elevated high-sensitivity C-reactive protein levels as independent risk factors for CI in CAPD patients (P < .05). Additionally, in this patient cohort, dialysis duration and residual renal function were protective factors against CI (P < .05). CI is prevalent among PD patients. Elevated high-sensitivity C-reactive protein levels, male gender, older age, lower educational attainment, and hypercholesterolemia constitute an independent risk factor for CI in CAPD patients, whereas residual renal function acts as a protective element.

A new approach for cognitive impairment pattern in chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is associated with an elevated risk of neurocognitive disorders (NCDs). It remains unclear whether CKD-related NCDs have a specific cognitive pattern or are earlier-onset phenotypes of the main NCDs (vascular NCDs and Alzheimer's disease).

METHODS

We used the Mini Mental State Examination score (MMSE) to assess cognitive patterns in 3003 CKD patients (stage 3-4) followed up over 5 years in the Chronic Kidney Disease-Renal Epidemiology and Information Network (CKD-REIN) cohort. After normalizing MMSE scores to a 0-to-100 scale, the associations between the baseline estimated glomerular filtration rate (eGFR, using the Chronic Kidney Disease Epidemiology Collaboration creatinine formula) and changes in each MMSE domain score were assessed in linear mixed models.

RESULTS

Patients (age: 67 ± 13 years old; males: 65%, mean eGFR: 33± 12 mL/min/1.73 m2) had a good baseline cognitive functions: the mean MMSE score was 26.9/30 ± 2.9. After adjustment for age, sex, educational level, depression (past or present), cardiovascular risk factors and cerebrovascular disease, a lower baseline eGFR (per 10 mL/min/1.73 m2) was associated with a 0.53-point decrement [P < .001; 95% confidence interval (CI) (-0.98, -0.08)] for orientation, a 1.04-point decrement [P = .03; 95% CI (-1.96, -0.13)] for attention and calculation, a 0.78-point decrement [P = .003; 95% CI (-1.30, -0.27)] for language, and a 0.94-point decrement [P = .02; 95% CI (-1.75, -0.13)] for praxis. Baseline eGFR was not, however, associated with significant changes over time in MMSE domain scores.

CONCLUSION

A lower eGFR in CKD patients was associated with early impairments in certain cognitive domains: praxis, language and attention domains before an obvious cognitive decline. Early detection of NCD in CKD patients must be performed before clinically cognitive decline using preferably tests assessing executive, attentional functions and language, rather than memory tests. This early cognitive screening could lead to a better management of cognitive impairment and their consequences on CKD management.

Elevated serum creatinine levels and risk of cognitive impairment in older adults with diabetes: a NHANES study from 2011-2014

Background

The brain and kidney have similar microvascular structure, which makes them susceptible to certain common pathophysiological processes. In this study, we examined several indicators of kidney injury/function associated with cognitive function in older diabetic patients in the hope of finding effective markers for detecting cognitive impairment (CI).

Methods

A total of 2209 older participants (aged ≥60 years) from the 2011-2014 National Health and Nutrition Examination Survey (NHANES) were analyzed for the association between diabetes and CI using a multiple linear regression analysis model. Using the same approach, we also analyzed the relationship between indicators of kidney injury/function and cognitive function (Animal Fluency Test, Digit Symbol Substitution Test) in the diabetic population.

Results

Diabetes was associated with CI. In age-adjusted model, older diabetics performed significantly poorer on tests of cognitive function compared to normoglycaemic individuals (1.145 points lower on the Animal Fluency Test (P = 0.005) and 7.868 points reduced on the Digit Symbol Substitution Test (P < 0.001)). In diabetics, we found elevated serum creatinine (SCr) (especially at SCr≥300uM) was associated with lower scores on cognitive function tests after strict adjustment for potential influences on cognitive function. While, albumin/creatinine ratio (ACR) was only associated with Digit Symbol Substitution score (DSS) not Animal Fluency score (AFS), and estimated glomerular filtration rate (eGFR) was only associated with CI (AFS and DSS) at the end-stage renal disease.

Conclusion

SCr, as a sensitive indicator of kidney injury, was significantly associated with CI and can potentially be used as an effective marker for screening CI in older diabetics.

Primary care biomarkers and dementia in people of the Torres Strait, Australia: extended data analysis

Objective

Dementia disproportionately affects First Nations populations. Biomarkers collected in primary care may assist with determining dementia risk. Our previous underpowered study showed some suggestive associations between baseline biomarkers with follow-up dementia or cognitive impairment. The current study extended this work with a larger linked dataset.

Study design and setting

Probabilistic data linkage was used to combine four baseline datasets with one follow-up assessment of dementia status 0-20 years later in a First Nations population in Australia. Mixed Effects Generalized Linear Regression models were used to test associations between baseline measures and follow-up status, accounting for repeated measures within individuals.

Results

Linked data were available for 88 individuals, with 101-279 baseline observations, depending on the type of measure. Higher urinary albumin to creatine ratio was associated with greater risk of cognitive impairment/dementia, whereas body weight and key lipid markers were negatively associated. There was no clear trend when these associations were examined by timing of measurement (i.e., ≤10 years or >10 years before a dementia assessment).

Conclusions

The results of this study support findings from our previous work and indicate that microalbuminuria can be an early indicator of dementia risk in this population. The weight and lipid profile findings reflect the mixed results in the published literature and require further investigation and interpretation.

Ankle-Brachial Index and Cardio-Ankle Vascular Index as Predictors of Cognitive Decline Over Time After Carotid Endarterectomy

Objective: Patients with carotid stenosis risk cognitive impairment even after carotid endarterectomy (CEA) because of the long-term presence of vascular risk factors. Early prediction of cognitive decline is useful because early appropriate training for impaired cognitive domains can improve their functions. Ankle-brachial index (ABI) and cardio-ankle vascular index (CAVI) are frequently used as general indicators of systemic atherosclerosis and are associated with cognitive function in the general population. This study aimed to evaluate the utility of those vascular biomarkers for predicting cognitive decline in patients after CEA.

Methods: Patients who had undergone both CEA at our institute and cognitive evaluations between March 2016 and January 2022 were invited to participate in this study. Associations between ABI or CAVI three years before baseline and cognitive function at baseline were assessed retrospectively in 94 patients, and associations between ABI or CAVI at baseline and three-year changes in cognitive functions were assessed prospectively in 24 patients. Cognitive functions were assessed using the Frontal Assessment Battery (FAB) and Neurobehavioral Cognitive Status Examination (Cognistat).

Results: Low ABI three years before baseline was associated with poor performances on Cognistat and FAB at baseline. ABI, as a continuous measure, three years before baseline, showed positive linear associations with total Cognistat score and subscores for naming, construction, and judgment at baseline. The Wilcoxon signed-rank test showed that the total Cognistat score, total FAB score, and subscores for attention and inhibitory control declined after three years. CAVI at baseline was negatively associated with three-year changes in total Cognistat score and subscores for naming, construction, and memory.

Conclusion: Cognitive function can decline over time in patients with carotid stenosis even after CEA. ABI and CAVI might be useful to predict cognitive function and its decline among patients who have undergone CEA.

The association between cognitive impairment/dementia and albuminuria: a systematic review and meta-analysis

Background

To identify the association between albuminuria and dementia or cognitive impairment.

Methods

The literature search was performed to identify relevant scientific studies through August 2019, including PubMed/Medline and EMBASE. For inclusion, the studies had to fulfil the following criteria: population-based cohort, case–control or cross-sectional studies; quantifying an association of albuminuria with cognitive impairment or dementia; and reported odds ratio (OR), and the corresponding 95% confidential interval (95% CI). Random effects model was used to yield pooled estimates.

Results

A total of 16 studies (11 cohort studies and five cross-sectional studies) were included in the meta-analyses. Based on the fully adjusted estimates, albuminuria was associated with a significant higher risk of cognitive impairment or dementia. Furthermore, the same trend existed for cognitive impairment and dementia, respectively. In addition, both of Alzheimer’s diseases (AD) and vascular dementia (VaD) were significantly associated with albuminuria.

Conclusion

Albuminuria was significantly associated with cognitive impairment and dementia. Corresponding to an earlier subclinical time-point in kidney disease progress, albuminuria may be a potential factor predicting the future occurrence of dementia.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10157-021-02127-3.

Urinary albumin creatinine ratio associated with postoperative delirium in elderly patients undergoing elective non-cardiac surgery: A prospective observational study

Introduction

The blood‐brain barrier (BBB) disruption contributes to postoperative delirium, but cost‐effective and non‐invasive assessment of its permeability is not practicable in the clinical settings. Urine albumin to creatinine ratio (UACR), reflecting systemic vascular endothelial dysfunction, may be a prognostic and predictive factor associated with postoperative delirium. The aim was to analyze the relationship between UACR and postoperative delirium in elderly patients undergoing elective non‐cardiac surgery.

Materials and methods

Through stratified random sampling, a cohort of 408 individuals aged 60 years and older scheduled for elective non‐cardiac surgery were included between February and August 2019 in the single‐center, prospective, observational study. The presence of delirium was assessed using the Confusion Assessment Method (CAM) or Confusion Assessment Method for the ICU (CAM‐ICU) on the day of surgery, at 2 h after the surgery ending time and on the first 3 consecutive days with repeated twice‐daily, with at least 6‐h intervals between assessments. Urine samples were collected on one day before surgery, and 1st day and 3rd day after surgery. The primary outcome was the presence of postoperative delirium, and association of the level of UACR with postoperative delirium was evaluated with unadjusted/adjusted analyses and multivariable logistic regression.

Results

Postoperative delirium was observed in 26.75% (107 of 400) of patients within 3 days post‐surgery. UACR‐Pre (OR, 1.30; 95% CI, 1.14–1.49, p < 0.001), UACR‐POD1 (OR, 1.20; 95% CI, 1.13–1.27, p < 0.001), and UACR‐POD3 (OR, 1.14; 95% CI, 1.08–1.20, p < 0.001) between the delirium and non‐delirium groups show a significant difference, even after adjusting for age, education levels, and other factors.

Conclusion

As the marker of endothelial dysfunction, the high perioperative UACR value may be linked to the postoperative delirium in elderly patients undergoing elective non‐cardiac surgery.

Association between the occurrence of albuminuria and the risk of early dementia among older people upon health examination: a community-based cohort study in Taiwan

OBJECTIVES

This study aimed to investigate the associations between biochemical markers, renal function, health behaviours and dementia among older people.

DESIGN

A retrospective cohort study.

SETTING

Community-based health examination database from Taipei city.

PARTICIPANTS

In total, 35 434 older people were included from February 2005 to December 2012. To assess changes in renal function, we selected participants who attended health examinations at least twice and responded to the AD8 questionnaire in 2012. We excluded those with dementia at baseline.

PRIMARY OUTCOME MEASURES

Early dementia was assessed using the AD8 questionnaire in 2012. Explanatory variables included demographic factors, health behaviours, biochemical markers and renal function. We used a Cox proportional hazard model to estimate the HR for early dementia onset.

RESULTS

Individuals with mild albuminuria (HR 1.228; 95% CI 1.066 to 1.414), lower eGFR (HR 1.549; 95% CI 1.319 to 1.820) and higher age (HR 1.022; 95% CI 1.015 to 1.028) were associated with a high risk of early dementia. Older people with no alcohol intake (HR 0.872; 95% CI 0.794 to 0.958), and higher education levels (HR 0.647; 95% CI 0.589 to 0.710) were at a low risk of early dementia.

CONCLUSIONS

Elevated mild albuminuria and low eGFR were associated with a high risk of early dementia in this community-based cohort. Routine health examinations for older people can help screen out the high-risk population, and clinical management might reduce or delay the risk of early dementia.

Systemic Inflammation Is Associated With Longitudinal Changes in Cognitive Performance Among Urban Adults

Objectives/Background: Systemic inflammation can affect cognitive performance over time. The current study examined associations between systemic inflammation and cognitive performance among African Americans and Whites urban adults, stratifying by sex, and age group and by race. Patients/Methods: Among 1,555-1,719 White and African-American urban adults [Age_base: 30-64y, 2004-2013, mean±SD follow-up time(y): 4.64 ± 0.93y], conducted linear mixed-effects regression models were conducted to test associations of inflammatory markers [C-reactive protein, Erythrocyte Sedimentation Rate (ESR), albumin, iron, and an inflammation composite score (ICS)] with longitudinal cognitive performance. Results: Among key findings, CRP was linked to poorer baseline mental status among younger women (≤50y, γ₀₁ = -0.03 ± 0.01, p = 0.002) and poorer attention in older women (>50y, γ₀₁ = -0.024 ± 0.007, p < 0.004) and African-Americans (γ₀₁ = -0.029 ± 0.008, p < 0.001). ESR was related to faster decline on verbal memory among older men (>50y, γ₁₁ = -0.008 ± 0.003, P = 0.009); with poorer performance on attention tests overall (γ₀₁ = -0.010 ± 0.003, P = 0.003) and among African-Americans (γ₀₁ = -0.013 ± 0.004, P = 0.002); on verbal fluency among older women (>50y,γ₀₁ = -0.037 ± 0.013, P = 0.004) and on executive function: overall (γ₀₁ = +0.62 ± 0.21, P = 0.004), older men (>50y, γ₀₁ = +1.69 ± 0.53, P = 0.001) and African-Americans (γ₀₁ = +0.84 ± 0.28, P = 0.002). Albumin was linked to slower attention decline among older men (>50y, γ₁₁ = +0.329 ± 0.103, P = 0.009), over-time improvement in executive function overall (γ₁₁ = -6.00 ± 2.26, P = 0.008), and better baseline psychomotor speed among African-Americans (γ₀₁ = +0.56 ± 0.19, P = 0.003). Finally, ICS predicted faster decline on visual memory/visuo-constructive abilities among older men (>50y, γ₁₁ = +0.17 ± 0.06, p = 0.003). Conclusion: In sum, strong associations between systemic inflammation and longitudinal cognitive performance were detected, largely among older individuals (>50y) and African-Americans. Randomized trials targeting inflammation are warranted.

Review: Relationship of type 2 diabetes to human brain pathology

Type 2 diabetes (T2D) and Alzheimer's disease (AD) are both highly prevalent diseases worldwide, and each is associated with high-morbidity and high-mortality. Numerous clinical studies have consistently shown that T2D confers a two-fold increased risk for a dementia, including dementia attributable to AD. Yet, the mechanisms underlying this relationship, especially nonvascular mechanisms, remain debated. Cerebral vascular disease (CVD) is likely to be playing a role. But increased AD neuropathologic changes (ADNC), specifically neuritic amyloid plaques (AP) and neurofibrillary tangles (NFT), are also posited mechanisms. The clinicopathological studies to date demonstrate T2D to be consistently associated with infarcts, particularly subcortical lacunar infarcts, but not ADNC, suggesting the association of T2D with dementia may largely be mediated through CVD. Furthermore, growing interest exists in insulin resistance (IR), particularly IR within the brain itself, which may be an associated but distinct phenomenon from T2D, and possibly itself associated with ADNC. Other mechanisms largely related to protein processing and efflux in the central nervous system with altered function in T2D may also be involved. Such mechanisms include islet amyloid polypeptide (or amylin) deposition, co-localized with beta-amyloid and found in more abundance in the AD temporal cortex, blood-brain barrier breakdown and dysfunction, potentially related to pericyte degeneration, and disturbance of brain lymphatics, both in the glial lymphatic system and the newly discovered discrete central nervous system lymph vessels. Medical research is ongoing to further disentangle the relationship of T2D to dementia in the ageing human brain.

Real-life helping behaviours in North America: A genome-wide association approach

In humans, prosocial behaviour is essential for social functioning. Twin studies suggest this distinct human trait to be partly hardwired. In the last decade research on the genetics of prosocial behaviour focused on neurotransmitters and neuropeptides, such as oxytocin, dopamine, and their respective pathways. Recent trends towards large scale medical studies targeting the genetic basis of complex diseases such as Alzheimer’s disease and schizophrenia pave the way for new directions also in behavioural genetics.

Based on data from 10,713 participants of the American Health and Retirement Study we estimated heritability of helping behaviour–its total variance explained by 1.2 million single nucleotide polymorphisms–to be 11%. Both, fixed models and mixed linear models identified rs11697300, an intergene variant on chromosome 20, as a candidate variant moderating this particular helping behaviour. We assume that this so far undescribed area is worth further investigation in association with human prosocial behaviour.

The Impact of Statin and Angiotensin-Converting Enzyme Inhibitor/Angiotensin Receptor Blocker Therapy on Cognitive Function in Adults With Human Immunodeficiency Virus Infection

BACKGROUND

Although statins, angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) are generally well tolerated, the impact of these therapies individually or in combination on the change in neurocognitive function in persons with human immunodeficiency virus infection is unknown.

METHODS

The study included participants in the AIDS Clinical Trials Group Longitudinal Linked Randomized Trials cohort participants not receiving a statin or ACEI/ARB within 30 days of first neurologic assessment (baseline), with assessments by NPZ-3 (z score of averaged Trailmaking A and B tests and digit symbol test [DST]) from ≥2 measurements. Marginal structural models estimated the causal effect of statin or ACEI/ARB initiation on neurocognitive function; initial constant slope was assumed during the first year of treatment and a second constant slope thereafter.

RESULTS

Of 3949 eligible participants, 16% started therapy with a statin, 11% with an ACEI/ARB, and 5% with both. Statin therapy had no significant effect on the composite NPZ-3 (primary outcome), Trailmaking B test, or DST. A small, nonsignificant positive effect on the Trailmaking A test was seen during year 1 (estimate, 0.088; 95% confidence interval, -.010 to .187; P = .08) and a small but significant negative effect (-0.033; -.058 to -.009; P = .007) in each subsequent year. ACEI/ARB therapy had a significant negative effect on the DST (-0.117; 95% confidence interval, -.217 to .016; P = .02) during year 1 but minimal effect in subsequent years or on other neurocognitive domains.

CONCLUSIONS

In summary, although modest declines in neurocognitive performance were seen in single domains with statin or ACEI/ARB therapy, we did not find consistent evidence that statins or ACEI/ARB have an effect on global neurocognitive function. Future studies should focus on long-term neurocognitive effects.

Cognitive Impairment and Dementia in Older Adults With Chronic Kidney Disease: A Review

Individuals with chronic kidney disease (CKD), especially older adults, are at more risk of experiencing cognitive impairment, possibly leading to mild cognitive impairment and/or dementia. Studies report associations between CKD and cognitive impairment; although unclear, there seems to be a graded association between stage of CKD and affected cognitive domains, with executive function being affected earlier in the process than episodic memory and global ability. In CKD, dysexecutive mild cognitive impairment and vascular dementia are also more prominent than other subtypes. Explanations are directed toward traditional and nontraditional vascular factors, which may also explain or mediate the association between CKD and type of cognitive impairment. Future research is urged to focus on the longitudinal association between specific domains of cognitive function, including executive function and memory and CKD; to develop screening tools fit for every CKD stage in elderly individuals, and lastly, to use imaging methods that may help clarify the underlying mechanisms connecting the kidney and the brain.

Ankle-Brachial Index: An Ubiquitous Marker of Cognitive Impairment-The EPIDEMCA Study

Epidemiological research on the implication of atherosclerosis in the development of cognitive impairment is lacking in low- and middle-income countries, where two-thirds of the individuals affected by dementia live. Individuals aged ≥65 years living in urban and rural areas of 2 countries in Central Africa were invited. Demographic, clinical, and biological data were collected, and the ankle-brachial index (ABI) was measured. Cognitive impairment was defined according to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria. Among 1662 participants (age 72.9 years, 59.3% females), the prevalence of cognitive impairment was 13.6%, which is higher in individuals with ABI ≤ 0.90 and ABI ≥ 1.40 than those with 0.90 < ABI < 1.40 (20.1% and 17% vs 12%, P = .0024). Cognitive impairment was significantly associated with the factors such as age (odds ratio [OR]: 1.09; 95% confidence interval [CI]: 1.07-1.12, P < .0001), female gender (OR: 2.36, 95% CI: 1.59-3.49, P < .0001), smoking (OR: 1.54, 95% CI: 1.06-2.23, P = .0026), and low ABI (≤0.90; OR: 1.52, 95% CI: 1.03-2.25, P = .0359). The ABI, a ubiquitous marker of atherosclerosis, provides independent and incremental information on susceptibility to present with cognitive disorders.

Impact of cystatin C and microalbuminuria on cognitive impairment in the population of community-dwelling Japanese

BACKGROUND AND AIMS

Cognitive impairment is an important element affecting our well-being, and as such, early diagnosis is critical today. We investigated whether serum cystatin C and microalbuminuria are associated with cognitive impairment.

METHODS

A total of 1943 subjects (774 males, 1169 females, mean age 65.8 years) took part in the investigation, and underwent a health examination in Tanushimaru, Japan, in 2009. The participants' cognitive function was evaluated using of mini-mental state examination (MMSE). We measured the levels of serum cystatin C using latex nephelometric immunoassay. Spot urine samples were used to measure microalbuminuria levels. Multivariate linear regression analyses were used to assess the relationship between MMSE scores and the level of cystatin C or microalbuminuria. All statistical analyses were performed using the SAS system.

RESULTS

The mean values of log-transformed serum cystatin C levels and log-transformed microalbuminuria were 0.95 (range 0.41-7.11) mg/L and 10.7 (range 1.1-2600) mg/g·Cr, respectively. The means of MMSE score were 27.7 ± 2.5. In the multivariate linear regression analyses adjusted for age and sex, MMSE was significantly associated with systolic blood pressure (p = 0.024, inversely), cystatin C (p = 0.046, inversely) and microalbuminuria (p = 0.019, inversely), whereas estimated glomerular filtration rate (eGFR) had an insignificant association (p = 0.197). In the multiple stepwise linear regression analysis, age, history of stroke, systolic blood pressure, serum cystatin C were independently associated with MMSE levels.

CONCLUSIONS

We demonstrated for the first time that cognitive function was significantly and inversely associated with cystatin C and microalbuminuria, in the relatively younger general population.

Cognitive Function and Kidney Disease: Baseline Data From the Systolic Blood Pressure Intervention Trial (SPRINT)

BACKGROUND

Chronic kidney disease is common and is associated with cardiovascular disease, cerebrovascular disease, and cognitive function, although the nature of this relationship remains uncertain.

STUDY DESIGN

Cross-sectional cohort using baseline data from the Systolic Blood Pressure Intervention Trial (SPRINT).

SETTING & PARTICIPANTS

Participants in SPRINT, a randomized clinical trial of blood pressure targets in older community-dwelling adults with cardiovascular disease, chronic kidney disease, or high cardiovascular disease risk and without diabetes or known stroke, who underwent detailed neurocognitive testing in the cognition substudy, SPRINT-Memory and Cognition in Decreased Hypertension (SPRINT-MIND).

PREDICTORS

Urine albumin-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR).

OUTCOMES

Cognitive function, a priori defined as 5 cognitive domains based on 11 cognitive tests using z scores, and abnormal white matter volume quantified by brain magnetic resonance imaging.

RESULTS

Of 9,361 SPRINT participants, 2,800 participated in SPRINT-MIND and 2,707 had complete data; 637 had brain imaging. Mean age was 68 years, 37% were women, 30% were black, and 20% had known cardiovascular disease. Mean eGFR was 70.8±20.9mL/min/1.73m² and median urine ACR was 9.7 (IQR, 5.7-22.5) mg/g. In adjusted analyses, higher ACR was associated with worse global cognitive function, executive function, memory, and attention, such that each doubling of urine ACR had the same association with cognitive performance as being 7, 10, 6, and 14 months older, respectively. Lower eGFR was independently associated with worse global cognitive function and memory. In adjusted models, higher ACR, but not eGFR, was associated with larger abnormal white matter volume.

LIMITATIONS

Cross-sectional only, no patients with diabetes were included.

CONCLUSIONS

In older adults, higher urine ACR and lower eGFR have independent associations with global cognitive performance with different affected domains. Albuminuria concurrently identifies a higher burden of abnormal brain white matter disease, suggesting that vascular disease may mediate these relationships.

Albuminuria in Association with Cognitive Function and Dementia: A Systematic Review and Meta-Analysis

OBJECTIVES

Cerebral microvascular disease is considered to contribute to cognitive dysfunction. We opted to explore whether albuminuria, a marker of systemic microangiopathy, is associated with cognitive impairment, dementia, and cognitive function.

DESIGN

Systematic review; independent reviewers screened 2359 articles, derived through the search strategy, for identification of observational studies quantifying an association of albuminuria with the outcomes of interest, abstracted data on study characteristics and results and evaluated studies on quality using the Newcastle-Ottawa scale.

SETTING

Community.

PARTICIPANTS

Adults.

MESUREMENTS

Cognitive impairment and dementia, defined by validated neuropsychological tests or clinical guidelines, respectively, and cognitive function, assessed by validated instruments.

RESULTS

Thirty-two eligible studies were identified. Albuminuria was associated with cognitive impairment (Odds Ratio (OR): 1.35, 95% Confidence Interval (CI): 1.19-1.53; 7,852 cases), dementia (OR: 1.35, 95% CI: 1.10-1.65; 5,758 cases), clinical Alzheimer's disease (OR: 1.37, 95% CI: 1.11-1.69; 629 cases) and vascular dementia (OR: 1.96, 95% CI: 1.16-3.31; 186 cases); the effect remained significant among longitudinal, population-based and high quality studies. Time-to-event analysis on prospective studies of non-demented at baseline individuals also showed a significant association with incident dementia (Risk Ratio: 1.52, 95% CI: 1.16-1.99; 971 cases). Worse global cognitive performance (Hedge's g: -0.13, 95% CI: -0.18, -0.09; 68,348 subjects) and accelerated cognitive decline (g: -0.20, 95% CI: -0.34, -0.07; 31,792 subjects) were noted among subjects with albuminuria, who also scored lower in executive function, processing speed, verbal fluency, and verbal memory.

CONCLUSIONS

Albuminuria was independently associated with cognitive impairment, dementia and cognitive decline. The stronger effects for vascular dementia and cognitive performance in domains primarily affected by microvascular disease support that the association could be mediated by shared microvascular pathology in the kidney and the brain.

Dementia is a risk factor for major adverse cardiac and cerebrovascular events in elderly Korean patients initiating hemodialysis: a Korean national population-based study

Background

Dementia is common in end-stage renal disease (ESRD) patients on hemodialysis (HD) and is associated with worse outcomes. This study aimed to investigate the risk of major adverse cardiac and cerebrovascular event (MACCE) in elderly patients with dementia initiating HD.

Methods

Using the database from the Health Insurance Review & Assessment Service, we analyzed 10,171 patients aged 65 years or older who had initiated dialysis from 2005 to 2008. MACCE was defined as a composite outcome of all-cause mortality, nonfatal acute myocardial infarction, target vessel revascularization, and nonfatal ischemic and hemorrhagic stroke. The Kaplan-Meier method and Cox proportional hazards model were used, and further comparisons using propensity-score matching at 1:2 ratio were also performed.

Results

A total of 303 elderly patients (3.0%) had dementia at initiating HD. During follow-up, dementia was a significant predictor of MACCE after adjustment for confounding variables. In addition, further analyzed in the propensity-score matched groups, dementia was an independent predictor of both nonfatal ischemic stroke and all-cause mortality.

Conclusions

Dementia is an independent risk factor for mortality and ischemic stroke in elderly ESRD patients initiating HD. Patients with dementia who start dialysis should be closely monitored to reduce the risk of mortality and ischemic stroke.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0547-0) contains supplementary material, which is available to authorized users.

Chronic kidney disease-related physical frailty and cognitive impairment: a systemic review

AIM

The objective of this review was to assess chronic kidney disease-related frailty and cognitive impairment, as well as their probable causes, mechanisms and the interventions.

METHODS

Studies from 1990 to 2015 were reviewed to evaluate the relationship between chronic kidney disease and physical frailty and cognitive impairment. Of the 1694 studies from the initial search, longitudinal studies (n = 22) with the keywords "Cognitive and CKD" and longitudinal or cross-sectional studies (n = 5) with the keywords "Frailty and CKD" were included in final analysis.

RESULTS

By pooling current research, we show clear evidence for a relationship between chronic kidney disease and frailty and cognitive impairment in major studies. Vascular disease is likely an important mediator, particularly for cognitive impairment. However, non-vascular factors also play an important role. Many of the other mechanisms that contribute to impaired cognitive function and increased frailty in CKD remain to be elucidated. In limited studies, medication therapy did not obtain the ideal effect. There are limited data on treatment strategies, but addressing the vascular disease risk factors earlier in life might decrease the subsequent burden of frailty and cognitive impairment in this population. Multidimensional interventions, which address both microvascular health and other factors, may have substantial benefits for both the cognitive impairments and physical frailty in this vulnerable population.

CONCLUSIONS

Chronic kidney disease is a potential cause of frailty and cognitive impairment. Vascular and non-vascular factors are the possible causes. The mechanism of chronic kidney disease-induced physical frailty and cognitive impairment suggests that multidimensional interventions may be effective therapeutic strategies in the early stage of chronic kidney disease. Geriatr Gerontol Int 2017; 17: 529-544.

Mid-life proteinuria and late-life cognitive function and dementia in elderly men: the Honolulu-Asia Aging Study

BACKGROUND

Impaired renal function has been linked to cognitive impairment. We assessed mid-life proteinuria and late-life cognitive function in elderly Asian men.

METHODS

The Honolulu Heart Program is a prospective study that began in 1965 with 8006 Japanese-American men aged 45 to 68 years. Mid-life proteinuria was detected by urine dipstick in 1971 to 1974. The Honolulu-Asia Aging Study began 20 years later, with cognitive assessment by the Cognitive Abilities Screening Instrument (CASI) in 3734 men. Standard criteria were used to classify 8-year incident dementia and subtypes.

RESULTS

The age-adjusted incidence of dementia increased significantly from 13.8, to 22.8, to 39.7 per 1000 person years follow-up, among those with no, trace, and positive mid-life proteinuria (P=0.004). Using linear regression adjusting for age, education, APOEε4, stroke, hypertension, systolic blood pressure, diabetes, fasting blood glucose, physical activity, and baseline CASI, those with positive proteinuria had significantly higher annual change in CASI over 8 years follow-up (-1.24, P=0.02) (reference=no proteinuria). Multivariate Cox regression found that positive proteinuria had a significant association with incident all-cause dementia (RR=2.66; 95%CI, 1.09-6.53; P=0.03), but no significant associations with incident Alzheimer disease or vascular dementia.

CONCLUSION

Mid-life proteinuria was an independent predictor for late-life incident all-cause dementia and cognitive decline over 8 years.

Association between functional performance and executive cognitive functions in an elderly population including patients with low ankle-brachial index

Introduction

Peripheral arterial disease, as measured by the ankle–brachial index (ABI), is prevalent among the elderly, and is associated with functional performance, assessed by the 6-minute walk test (6MWT). Executive cognitive function (ECF) impairments are also prevalent in this population, but no existing study has investigated the association between ECF and functional performance in an elderly population including individuals with low ABI.

Aim

To investigate the association between functional performance, as measured by the 6MWT, and loss in ECF, in an elderly sample including individuals with low ABI.

Method

The ABI group was formed by 26 elderly individuals with low ABI (mean ABI: 0.63±0.19), and the control group was formed by 40 elderly individuals with normal ABI (mean ABI: 1.08±0.07). We analyzed functional performance using the 6MWT, global cognition using the Mini-Mental State Examination (MMSE), and ECF using the Digit Span for assessing attention span and working memory, the Stroop Color Word Test (SCWT) for assessing information processing speed and inhibitory control/impulsivity, and the Controlled Oral Word Association Test (COWAT) for assessing semantic verbal fluency and phonemic verbal fluency. We also used a factor analysis on all of the ECF tests (global ECF).

Results

Before adjustment, the ABI group performed worse on global cognition, attention span, working memory, inhibitory control/impulsivity, semantic verbal fluency, and phonemic verbal fluency. After adjustment, the ABI group performance remained worse for working memory and semantic verbal fluency. In a simple correlation analysis including all of the subjects, the 6MWT was associated with global cognition, attention span, working memory, information processing speed, inhibitory control/impulsivity, semantic verbal fluency, and global ECF. After adjustment, all the associations remained statistically significant.

Conclusion

This study found an independent association between functional performance and ECF in an elderly population including low ABI individuals, showing that, in elderly populations with functional impairment, ECF may also be impaired.

Neuropsychological performance is positively associated with plasma albumin in healthy adults

BACKGROUND

Albumin serves a range of physiological functions that are vital to overall brain and cognitive health. Indeed, associations between cognitive performance and albumin have been demonstrated in individuals with chronic liver or kidney disease and in patients with a high urinary excretion of albumin. However, an association of plasma albumin with cognitive performance has not been reported in otherwise healthy participants with clinically acceptable plasma albumin concentrations.

METHOD

This study utilized a wide-ranging neuropsychological test battery to investigate the relationship between cognitive performance and plasma albumin homeostasis in 222 healthy participants (143 females) between the ages of 43 and 84 years (mean 65 years).

RESULTS

Albumin both with and without the covariates of age, sex and acute-phase proteins was positively associated with enhanced performance on a range of neuropsychological domains including perceptual speed, Stroop and verbal ability. Albumin manifested generally positive but less robust associations with secondary and primary memory.

CONCLUSION

The results indicate that there is a positive association between albumin and cognitive performance in physiologically healthy participants free of chronic renal or liver disease.

Proteinuria is associated with neurocognitive impairment in antiretroviral therapy treated HIV-infected individuals

BACKGROUND

Proteinuria is a marker of vascular dysfunction that predicted increased cardiovascular mortality and is associated with neurocognitive impairment (NCI) in population-based studies. We examined associations between proteinuria and HIV-associated NCI.

METHODS

Multivariable logistic regression was used to examine associations between NCI at the first neurocognitive assessment (baseline) and simultaneous, clinically significant proteinuria [as random spot urine protein-to-creatinine ratios (UP/Cr) ≥200 mg/g] in a prospective multicenter observational cohort study. Generalized estimating equations were used to examine associations between baseline proteinuria and subsequent NCI among subjects without NCI at baseline. NCI was defined as a Z-score, derived from the combination of normalized scores from the Trailmaking A and B and the Wechsler Adult Intelligence Scale-Revised Digit Symbol tests.

RESULTS

A total of 1972 subjects were included in this analysis. Baseline proteinuria was associated with increased odds of NCI [odds ratio (OR): 1.41, 95% confidence interval (CI): 1.08 to 1.85; P = 0.01] and with subsequent NCI among subjects without NCI at baseline (OR: 1.39, 95% CI: 1.01 to 1.93; P = 0.046) in multivariable models adjusted for risk factors and potential confounders. Similar associations were evident when these analyses were limited to visits at which time study subjects maintained plasma HIV RNA levels <200 copies per milliliter.

CONCLUSIONS

The association between proteinuria and NCI observed in this study adds to a growing body of evidence implicating contributions by vascular disease to NCI in antiretroviral treated individuals. Studies examining interventions that improve vascular function are warranted.

Clinical practice guideline for the management of chronic kidney disease in patients infected with HIV: 2014 update by the HIV Medicine Association of the Infectious Diseases Society of America

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Cognitive performance before and during hemodialysis: a randomized cross-over trial

BACKGROUND AND AIMS

Hemodialysis (HD) patients are educated and counseled during the HD procedure. There are few studies assessing whether cognitive performance varies with dialysis.

METHODS

Using a randomized cross-over design, 40 patients were assigned to one of two sequences: testing 1 h before dialysis followed 1 month later by testing during the first hour of dialysis (n = 21) versus testing during the first hour of dialysis followed 1 month later by 1 h before dialysis (n = 19). Cognitive tests were administered at each testing period. Mixed regression models evaluated for a dialysis effect (difference between test performance before vs. during dialysis) while adjusting for potential learning (difference between first and second tests).

RESULTS

In models accounting for period of testing, there was no difference in test performance between 1 h before versus during the first hour of HD for all administered cognitive tests (p > 0.05). A learning effect was detected between first and second test administration in two tests, specifically, the Word List Learning and the Digit Symbol Substitution Test.

CONCLUSIONS

We found no difference in cognitive performance depending on the time of testing, suggesting that cognitive tests performed during the first hour of dialysis are a valid assessment of cognitive performance.

Lower ankle-brachial index is related to worse cognitive performance in old age

Objective: We aimed to study the associations between peripheral artery disease (PAD) and ankle-brachial index (ABI) and performance in a range of cognitive domains in nondemented elderly persons. Methods: Data were collected within the Lothian Birth Cohort 1921 and 1936 studies. These are two narrow-age cohorts at age 87 (n = 170) and 73 (n = 748) years. ABI was analyzed as a dichotomous (PAD vs. no PAD) and a continuous measure. PAD was defined as having an ABI less than 0.90. Measures of nonverbal reasoning, verbal declarative memory, verbal fluency, working memory, and processing speed were administered. Both samples were screened for dementia. Results: We observed no significant differences in cognitive performance between persons with or without PAD. However, higher ABI was associated with better general cognition (β = .23, p = .02, R² change = .05) and processing speed (β = .29, p < .01, R² change = .08) in the older cohort and better processing speed (β = .12, p < .01, R² change = .01) in the younger cohort. This was after controlling for age, sex, and childhood mental ability and excluding persons with abnormally high ABI (>1.40) and a history of cardiovascular or cerebrovascular disease. Conclusion: Lower ABI is associated with worse cognitive performance in old age, especially in the oldest old (>85 years), possibly because of long-term exposure to atherosclerotic disease. Interventions targeting PAD in persons free of manifest cardiovascular and cerebrovascular disease may reduce the incidence of cognitive impairment and dementia.

Relationship between longitudinal measures of renal function and onset of dementia in a community cohort of older adults

OBJECTIVES

To evaluate the association between dynamic measures of renal function ascertained over time and onset of dementia.

DESIGN

Prospective community cohort study.

SETTING

Group Health, Seattle, Washington.

PARTICIPANTS

Two thousand nine hundred sixty-eight adults aged 65 and older followed for the development of dementia over a median of 6.0 years (interquartile range 3.1-10.1 years).

MEASUREMENTS

Time-varying measures of renal function were constructed based on 49,340 serum creatinine measurements and included average estimated glomerular filtration rate (eGFR), eGFR trajectory, and variability in eGFR around this trajectory over 5-year exposure windows. The association between these three eGFR exposure measures and risk of dementia was estimated using a Cox regression model adjusted for other participant characteristics. Time-varying measures of urine protein by dipstick were also adjusted for in sensitivity analyses.

RESULTS

Participants with a lower eGFR had a higher incidence of dementia, but this did not reach statistical significance in adjusted analyses (omnibus P = .14). There were trends toward a higher adjusted incidence of dementia in participants with positive eGFR trajectories (omnibus P = .07) and greater variability in eGFR (omnibus P = .04) over time. The results of sensitivity analyses, including those in which time-varying measures of proteinuria were included, were consistent with those of the primary analysis.

CONCLUSION

In a community cohort of older adults followed for a median of 6 years, strong associations were not found between measures of kidney disease severity and progression and incident dementia.

Albuminuria and cognitive functioning in an older population: the Hoorn study

BACKGROUND/AIMS

Markers of vascular disease elsewhere in the body may reflect vascular abnormalities in the brain relevant to age-related cognitive decline and dementia. We examined the association between albuminuria, as a marker of microvascular damage, and cognition in older individuals.

METHODS

380 individuals (age 73 ± 6 years), participating in the population-based Hoorn Study, underwent extensive neuropsychological examination in 2005-2008, and urinary albumin-to-creatinine ratios measurements in 2000-2001 (n = 378) and/or 2005-2008 (n = 346). Cognition was expressed in z-scores on 6 domains.

RESULTS

In 2000-2001, 42 participants were with and 336 without albuminuria, and in 2005-2008 51 were with and 295 were without. In age-, sex- and premorbid IQ-adjusted analyses, participants with albuminuria 5-7 years earlier had slightly lower z-scores for the domains attention and executive functioning [mean difference: -0.21 (95% CI -0.40 to -0.02)] and language [-0.36 (95% CI -0.63 to -0.09)]. No statistically significant differences in cognition were found between participants with and without albuminuria at the time of neuropsychological testing.

CONCLUSION

Albuminuria predicts future modest cognitive decrements, but concurrent albuminuria is unrelated to cognitive functioning. The link between albuminuria and cognitive dysfunction may convey an etiological message, but because effect sizes were modest its value in prognostic models for cognitive decline may be limited.

Kidney dysfunction and cognitive decline in women

BACKGROUND AND OBJECTIVES

ESRD is associated with substantial cognitive deficits but whether earlier kidney dysfunction predicts cognitive decline is less well defined.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

More than 1700 women aged ≥70 years in the Nurses' Health Study had plasma creatinine and urinary albumin/creatinine ratios (ACRs) measured in 2000, within 12 months of their initial cognitive testing. These participants had repeated assessments of cognition administered by phone every 2 years, including tests for general cognition, verbal memory, verbal fluency, and working memory for up to 6 years of follow-up. Mixed-effects regression analysis was applied to calculate mean differences in the rate of cognitive decline between women with an estimated GFR <60 ml/min per 1.73 m(2) or an ACR ≥5 mg/g versus referent levels.

RESULTS

The median age was 74 years at initial cognitive testing, 99% of women were Caucasian, median plasma creatinine was 0.8 mg/dl, and 25% had an ACR ≥5 mg/g. The difference in cognitive decline with a baseline ACR ≥5 mg/g versus an ACR <5 mg/g was equivalent to the difference observed with 2-7 years of aging; that is, a higher ACR was associated with 2-7 times faster decline in all four cognitive domains assessed (all P values <0.05) than that attributed to each 1 year of aging alone. No associations were observed between an eGFR <60 ml/min per 1.73 m(2) and cognitive decline.

CONCLUSIONS

A baseline urinary ACR ≥5 mg/g, a level not traditionally considered clinically significant, is independently associated with faster decline in cognitive function.

Diabetic peripheral microvascular complications: relationship to cognitive function

Peripheral microvascular complications in diabetes are associated with concurrent cerebrovascular disease. As detailed cognitive assessment is not routinely carried out among diabetic patients, the aim was to establish whether the presence of clinical "peripheral" microvascular disease can identify a subgroup of patients with early evidence of cognitive impairment. Detailed psychometric assessment was performed in 23 diabetic patients with no microvascular complications (Group D), 27 diabetic patients with at least one microvascular complication: retinopathy, neuropathy, and/or nephropathy (Group DC), and 25 healthy controls (Group H). Groups D and DC participants had significantly lower scores on reaction time (P = 0.003 and 0.0001, resp.) compared to controls. Similarly, groups D and DC participants had significantly lower scores on rapid processing of visual information (P = 0.034 and 0.001, resp.) compared to controls. In contrast, there was no significant difference between Groups D and DC on any of the cognitive areas examined. The results show that diabetes, in general, is associated with cognitive dysfunction, but the additional presence of peripheral microvascular disease does not add to cognitive decline. The study, however, indirectly supports the notion that the aetiology of cognitive impairment in diabetes may not be restricted to vascular pathology.

Microalbuminuria: marker or maker of cardiovascular disease

Advancing age is associated with albuminuria and vascular changes. This review will explore the putative links between the two. Vascular ageing involves endothelial dysfunction as well as increased arterial diameter, wall thickness and stiffness, ultimately leading to arterial sclerosis. This process is accelerated by a defective vascular repair process. Endothelial dysfunction is likely to be involved in the initiation and development of microalbuminuria. It is often followed by the development and progression of atherosclerosis. Initially, microalbuminuria is reversible but becomes fixed with the progression of vascular structural changes including glomerulosclerosis. The prevalence of microalbuminuria increases with age and has been shown to be a marker of widespread microvasculopathy at various levels including cerebral, cardiac and renal microcirculations. This has been linked to endpoint clinical events, with microalbuminuria increasing the risk of cognitive impairment and strokes, cardiovascular disease outcomes, and progression to end-stage renal failure. Evidence of microvascular damage such as microalbuminuria associated with increased cardiovascular risk may suggest that microvascular damage and dysfunction predate overt macrovascular disease. Microalbuminuria and reduced glomerular filtration rate (GFR) may be markers of different pathologic processes. It is likely that microalbuminuria and reduced GFR simply represent, respectively, the spectrum of renal vascular manifestations from systemic endothelial dysfunction (microvascular disease) to systemic atherosclerosis (macrovascular disease).

Cardiovascular disease and cognitive function in maintenance hemodialysis patients

BACKGROUND

Cardiovascular disease (CVD) and cognitive impairment are common in dialysis patients. Given the proposed role of microvascular disease on cognitive function, particularly cognitive domains that incorporate executive functions, we hypothesized that prevalent systemic CVD would be associated with worse cognitive performance in hemodialysis patients.

DESIGN

Cross-sectional cohort.

SETTING & PARTICIPANTS

200 maintenance hemodialysis patients without prior stroke from 5 Boston-area hemodialysis units.

PREDICTOR

CVD, defined as history of coronary disease or peripheral vascular disease.

OUTCOME

Performance on a detailed neurocognitive battery. Primary analyses quantified cognitive performance using principal components analysis to reduce cognitive tests to a processing speed/executive function domain and a memory domain. Multivariable linear regression models adjusted for age, sex, education, race, and other clinical and demographic characteristics.

RESULTS

Mean age of participants was 62 ± 18 (standard deviation) years and 75 (38%) had CVD. Individuals with CVD were older and more likely to be men, have diabetes, and be current or former smokers. In adjusted models, individuals with CVD performed 0.50 standard deviation worse (P < 0.001) on tests assessing processing speed/executive function, whereas there was no difference in performance on tests of memory. Similar results were seen assessing individual tests, with performance on the Block Design, Digit Symbol Coding, and Trail Making Tests A and B significantly associated with CVD in age-, sex-, education-, and race-adjusted analyses and approaching significance in fully adjusted models.

LIMITATIONS

CVD ascertainment dependent on patient recall and dialysis unit documentation. No brain imaging.

CONCLUSIONS

The presence of CVD is associated with worse cognitive performance on tests of processing speed and executive functioning in hemodialysis patients and identifies a high-risk population for greater difficulty with complex tasks.

Association of cognitive function with albuminuria and eGFR in the general population

BACKGROUND AND OBJECTIVES

Recent studies found different associations of cognitive function with albuminuria or estimated GFR (eGFR). Most studies were limited to the elderly or did not take both renal variables into account. Therefore, this study analyzed the association of cognitive function with albuminuria and eGFR in community-dwelling persons aged 35 to 82 years.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a cross-sectional study comprising 4095 participants of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study. Cognitive function, measured with the Ruff Figural Fluency Test (RFFT), was treated as the dependent variable, and albuminuria and eGFR were treated as independent variables.

RESULTS

The prevalence of albuminuria <10, 10 to 29, and ≥30 mg/24 h was 54%, 31%, and 15%, respectively. Mean eGFR (± SD) was 79 ± 15 ml/min per 1.73 m(2). Because of interaction between albuminuria and age, analyses were performed per age tertile. After multivariate adjustment, albuminuria ≥ 30 mg/24 h, but not eGFR, was associated with lower RFFT score in the youngest tertile (B -5.3; 95% CI, -0.6 to -9.2; P = 0.05), but not in older tertiles. Moreover, subjects in the youngest tertile with increasing albuminuria (5-15 and >15 mg/24 h) before RFFT measurement had lower mean RFFT scores than subjects with stable albuminuria: mean difference -4.9 (P = 0.3) and -6.7 (P = 0.03), respectively.

CONCLUSIONS

In this community-based cohort, elevated albuminuria was associated with worse cognitive function in young but not in old persons. There was no association of eGFR with cognitive function.

Vascular risk factors and cognitive impairment in chronic kidney disease: the Chronic Renal Insufficiency Cohort (CRIC) study

BACKGROUND AND OBJECTIVES

Cognitive impairment is common among persons with chronic kidney disease, but the extent to which nontraditional vascular risk factors mediate this association is unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted cross-sectional analyses of baseline data collected from adults with chronic kidney disease participating in the Chronic Renal Insufficiency Cohort study. Cognitive impairment was defined as a Modified Mini-Mental State Exam score>1 SD below the mean score.

RESULTS

Among 3591 participants, the mean age was 58.2±11.0 years, and the mean estimated GFR (eGFR) was 43.4±13.5 ml/min per 1.73 m2. Cognitive impairment was present in 13%. After adjustment for demographic characteristics, prevalent vascular disease (stroke, coronary artery disease, and peripheral arterial disease) and traditional vascular risk factors (diabetes, hypertension, smoking, and elevated cholesterol), an eGFR<30 ml/min per 1.73 m2 was associated with a 47% increased odds of cognitive impairment (odds ratio 1.47, 95% confidence interval 1.05, 2.05) relative to those with an eGFR 45 to 59 ml/min per 1.73 m2. This association was attenuated and no longer significant after adjustment for hemoglobin concentration. While other nontraditional vascular risk factors including C-reactive protein, homocysteine, serum albumin, and albuminuria were correlated with cognitive impairment in unadjusted analyses, they were not significantly associated with cognitive impairment after adjustment for eGFR and other confounders.

CONCLUSIONS

The prevalence of cognitive impairment was higher among those with lower eGFR, independent of traditional vascular risk factors. This association may be explained in part by anemia.

Dementia and cognitive impairment in ESRD: diagnostic and therapeutic strategies

Cognitive impairment, including dementia, is a common but poorly recognized problem among patients with end-stage renal disease (ESRD), affecting 16-38% of patients. Dementia is associated with high risks of death, dialysis withdrawal, hospitalization, and disability among patients with ESRD; thus, recognizing and effectively managing cognitive impairment may improve clinical care. Dementia screening strategies should take into account patient factors, the time available, the timing of assessments relative to dialysis treatments, and the implications of a positive screen for subsequent management (for example, transplantation). Additional diagnostic testing in patients with cognitive impairment, including neuroimaging, is largely based on the clinical evaluation. There is limited data on the efficacy and safety of pharmacotherapy for dementia in the setting of ESRD; therefore, decisions about the use of these medications should be individualized. Management of behavioral symptoms, evaluation of patient safety, and advance care planning are important components of dementia management. Prevention strategies targeting vascular risk factor modification, and physical and cognitive activity have shown promise in the general population and may be reasonably extrapolated to the ESRD population. Modification of ESRD-associated factors such as anemia and dialysis dose or frequency require further study before they can be recommended for treatment or prevention of cognitive impairment.

A prospective study of albuminuria and cognitive function in older adults: the Rancho Bernardo study

Chronic kidney disease is a risk factor for cognitive impairment. Albuminuria is an early manifestation of chronic kidney disease and a marker of endothelial dysfunction and vascular risk. Results of prior studies of albuminuria and cognitive function are contradictory. The authors studied 1,345 community-dwelling women and men in southern California (mean age, 75 years) at a 1992-1996 research clinic visit, when urine albumin/creatinine ratio (ACR) was measured in spot morning urine and cognitive function was evaluated by using the Mini-Mental State Examination Trail-Making Test B, and category fluency test. An ACR of > or =30 mg/g was found in 17% of women and 15% of men in 1992-1996. Analysis of covariance was used to compare cognitive function score by categorical ACR. Between 1999 and 2002, 759 participants returned for repeat cognitive function testing. For men, but not women, baseline albuminuria, but not estimated glomerular filtration rate, was associated with reduced cognitive function at follow-up on all tests (P's < 0.05). An ACR of > or =30 mg/g was associated with greater annual decline in Mini-Mental State Examination and category fluency scores. Albuminuria may be an easily measured marker predicting future cognitive function decline. Results imply a common underlying mechanism affecting the renal and cerebral microvasculature.

CKD associates with cognitive decline

Cognitive impairment and chronic kidney disease (CKD) will become increasingly prevalent in the aging US population. Although evidence exists that CKD is a risk factor for cognitive decline, longitudinal studies are limited and largely have excluded ethnically diverse populations. The Northern Manhattan Study includes a population-based, prospective, stroke-free cohort. We assessed global cognitive function annually using the modified Telephone Interview for Cognitive Status (TICS-m) and estimated kidney function using Cockcroft-Gault creatinine clearance (CCl), Modification of Diet in Renal Disease estimated GFR (eGFR), and serum creatinine (sCr). We examined the association between CKD and change in TICS-m scores over time, adjusting for sociodemographic and vascular risk factors. Of 2172 subjects (mean age 71.5 yr, mean follow-up 2.9 yr), 59% were Hispanic, 20% were black, and 63% were women. Participants with a CCl <60 ml/min and those with a CCl between 60 and 90 ml/min performed significantly worse on the TICS-m over time than those with a CCl >90 ml/min, adjusting for potential confounders. Our results were similar when we used eGFR or sCr to estimate kidney function. In conclusion, decreased kidney function associates with greater cognitive decline, even in those with mild CKD. Kidney disease may represent a novel mechanism leading to cognitive impairment and a target for early intervention.

Effects of central arterial aging on the structure and function of the peripheral vasculature: implications for end-organ damage

Over the past decade, numerous studies have shown that increased aortic stiffness is associated with major cardiovascular disease end points, including heart disease, stroke, and kidney disease. Cardiac abnormalities and enhanced atherogenesis in the setting of increased pulsatile load on heart and arteries have been well described. However, recent studies have shown a further association between excessive pressure pulsatility and a number of afflictions of aging that share a predominant microvascular etiology, including many forms of kidney disease and cognitive impairment. In these disorders, microvascular remodeling and impaired regulation of local blood flow, which are related to large artery stiffness and pressure pulsatility, are associated with evidence of diffuse microscopic tissue damage. This brief review will summarize age-related changes in aortic and peripheral vascular function and will discuss potential mechanisms leading from changes in properties of large arteries to excessive pressure pulsatility, abnormal microvascular structure and function, and end-organ dysfunction and damage.

The role of microalbuminuria and insulin resistance as significant risk factors for white matter lesions in Japanese type 2 diabetic patients

OBJECTIVE

The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. Microalbuminuria, which is associated with diabetes, has been flagged as a novel predictor for cerebrovascular events. This preliminary study was therefore designed to test the hypothesis that the presence of WML correlates with microalbuminuria and insulin resistance in patients with type 2 diabetic mellitus (DM) not receiving insulin treatment.

PATIENTS AND METHODS

Based on brain magnetic resonance imaging (MRI) findings, 90 type 2 diabetic patients were divided into two groups: a WML-positive group (57+/-8 years, mean+/-SD, n=34) and a WML-negative group (57+/-6 years, n=56). The level of blood glucose was assessed by fasting plasma glucose (FPG), fasting immunoreactive insulin (F-IRI), homeostasis model assessment (HOMA) index, and hemoglobin A(1c) (HbA1c).

RESULTS

The body mass index was higher in the WML-positive group than in the WML-negative group (p<0.01). Plasma levels of triglycerides were higher while high-density lipoprotein cholesterol (HDL-C) was lower in the WML-positive group than in the WML-negative group (p<0.05 and p<0.0001, respectively). Fasting plasma glucose (p<0.005), insulin concentrations (p<0.0001), HOMA index (p<0.0001), and urinary albumin excretion (p<0.0001) levels were higher in the WML-positive group than in the WML-negative group. Multivariate logistic analysis revealed that WML was independently predicted by the microalbuminuria and insulin resistance (p<0.005, p<0.0005, respectively).

CONCLUSION

The results of this preliminary study indicate that the presence of WML was associated with the microalbuminuria and insulin resistance in these Japanese patients with type 2 DM; larger cohort studies are warranted to confirm these findings.