Moderate chronic kidney disease is associated with reduced cognitive performance in midlife women

Update on Hemodialysis-Induced Multiorgan Ischemia: Brains and Beyond

Hemodialysis is a life-saving treatment for patients with kidney failure. However, patients requiring hemodialysis have a 10-20 times higher risk of cardiovascular morbidity and mortality than that of the general population. Patients encounter complications such as episodic intradialytic hypotension, abnormal perfusion to critical organs (heart, brain, liver, and kidney), and damage to vulnerable vascular beds. Recurrent conventional hemodialysis exposes patients to multiple episodes of circulatory stress, exacerbating and being aggravated by microvascular endothelial dysfunction. This promulgates progressive injury that leads to irreversible multiorgan injury and the well-documented higher incidence of cardiovascular disease and premature death. This review aims to examine the underlying pathophysiology of hemodialysis-related vascular injury and consider a range of therapeutic approaches to improving outcomes set within this evolved rubric.‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬.

Association of Plant-Based Protein Intake with Cognitive Function in Adults with CKD

Key Points

Higher plant protein intake was associated with higher cognitive scores in people with kidney disease. Future trials are needed to determine whether increasing plant protein intake improves measures of cognition in patients with kidney disease.

Background

Patients with CKD have accelerated cardiovascular and cognitive aging when compared with the non-CKD population. This cognitive decline contributes to excessive rates of physical and functional decline, reduced quality of life, and mortality in the CKD population. Mediterranean diets, a plant-forward diet, have been associated with positive cognitive performance in the general non-CKD population and with some beneficial outcomes in CKD. However, it is still unclear whether plant-based diets are associated with cognitive decline in patients with CKD.

Methods

Using the National Health and Nutrition Examination Survey 2011–2012 and 2013–14 data, we conducted a secondary analysis evaluating the relationship of plant-based and unprocessed plant protein with cognitive outcome measures in eligible participants aged 60 years and older. All data were extracted from the available National Health and Nutrition Examination Survey demographic, questionnaire, examination, and laboratory data. CKD was calculated and defined in participants as urine albumin to creatinine ratio ≥30 mg/g and/or eGFR <60 ml/min. In incremental models, we adjusted for total energy intake, age, sex, race/ethnicity, body mass index, total energy intake, diabetes, hypertension, education, smoking, and alcohol.

Results

Higher plant-based protein above median dietary intakes was significantly associated with higher executive function scores in participants with CKD (P < 0.05). For all patients and in those with CKD, plant-based protein was significantly associated (P < 0.05) with higher composite cognitive scores in nearly all statistical models. Higher unprocessed plant protein was significantly associated (P < 0.05) with higher composite cognitive scores in all categorical models.

Conclusions

Higher plant protein intake was a significant predictor of certain individual and composite cognitive score measures within the general and in the CKD population. Future interventional trials are needed to determine whether increasing plant-based protein intake improves measures of cognition in patients with CKD.

Hemodialysis-Related Acute Brain Injury Demonstrated by Application of Intradialytic Magnetic Resonance Imaging and Spectroscopy

SIGNIFICANCE STATEMENT

Hemodialysis (HD) results in reduced brain blood flow, and HD-related circulatory stress and regional ischemia are associated with brain injury over time. However, studies to date have not provided definitive direct evidence of acute brain injury during a HD treatment session. Using intradialytic magnetic resonance imaging (MRI) and spectroscopy to examine HD-associated changes in brain structure and neurochemistry, the authors found that multiple white (WM) tracts had diffusion imaging changes characteristic of cytotoxic edema, a consequence of ischemic insult and a precursor to fixed structural WM injury. Spectroscopy showed decreases in prefrontal N -acetyl aspartate (NAA) and choline concentrations consistent with energy deficit and perfusion anomaly. This suggests that one HD session can cause brain injury and that studies of interventions that mitigate this treatment's effects on the brain are warranted.

BACKGROUND

Hemodialysis (HD) treatment-related hemodynamic stress results in recurrent ischemic injury to organs such as the heart and brain. Short-term reduction in brain blood flow and long-term white matter changes have been reported, but the basis of HD-induced brain injury is neither well-recognized nor understood, although progressive cognitive impairment is common.

METHODS

We used neurocognitive assessments, intradialytic anatomical magnetic resonance imaging, diffusion tensor imaging, and proton magnetic resonance spectroscopy to examine the nature of acute HD-associated brain injury and associated changes in brain structure and neurochemistry relevant to ischemia. Data acquired before HD and during the last 60 minutes of HD (during maximal circulatory stress) were analyzed to assess the acute effects of HD on the brain.

RESULTS

We studied 17 patients (mean age 63±13 years; 58.8% were male, 76.5% were White, 17.6% were Black, and 5.9% were of Indigenous ethnicity). We found intradialytic changes, including the development of multiple regions of white matter exhibiting increased fractional anisotropy with associated decreases in mean diffusivity and radial diffusivity-characteristic features of cytotoxic edema (with increase in global brain volumes). We also observed decreases in proton magnetic resonance spectroscopy-measured N -acetyl aspartate and choline concentrations during HD, indicative of regional ischemia.

CONCLUSIONS

This study demonstrates for the first time that significant intradialytic changes in brain tissue volume, diffusion metrics, and brain metabolite concentrations consistent with ischemic injury occur in a single dialysis session. These findings raise the possibility that HD might have long-term neurological consequences. Further study is needed to establish an association between intradialytic magnetic resonance imaging findings of brain injury and cognitive impairment and to understand the chronic effects of HD-induced brain injury.

CLINICAL TRIALS INFORMATION

NCT03342183 .

The Construction of a Multidomain Risk Model of Alzheimer's Disease and Related Dementias

BACKGROUND

Alzheimer's disease (AD) and related dementia (ADRD) risk is affected by multiple dependent risk factors; however, there is no consensus about their relative impact in the development of these disorders.

OBJECTIVE

To rank the effects of potentially dependent risk factors and identify an optimal parsimonious set of measures for predicting AD/ADRD risk from a larger pool of potentially correlated predictors.

METHODS

We used diagnosis record, survey, and genetic data from the Health and Retirement Study to assess the relative predictive strength of AD/ADRD risk factors spanning several domains: comorbidities, demographics/socioeconomics, health-related behavior, genetics, and environmental exposure. A modified stepwise-AIC-best-subset blanket algorithm was then used to select an optimal set of predictors.

RESULTS

The final predictive model was reduced to 10 features for AD and 19 for ADRD; concordance statistics were about 0.85 for one-year and 0.70 for ten-year follow-up. Depression, arterial hypertension, traumatic brain injury, cerebrovascular diseases, and the APOE4 proxy SNP rs769449 had the strongest individual associations with AD/ADRD risk. AD/ADRD risk-related co-morbidities provide predictive power on par with key genetic vulnerabilities.

CONCLUSION

Results confirm the consensus that circulatory diseases are the main comorbidities associated with AD/ADRD risk and show that clinical diagnosis records outperform comparable self-reported measures in predicting AD/ADRD risk. Model construction algorithms combined with modern data allows researchers to conserve power (especially in the study of disparities where disadvantaged groups are often grossly underrepresented) while accounting for a high proportion of AD/ADRD-risk-related population heterogeneity stemming from multiple domains.

Quality of life and cognitive assessment in healthy older Asian people with early and moderate chronic kidney disease: The NAHSIT 2013–2016 and validation study

Background

Taiwan has the highest prevalence of chronic kidney disease (CKD). Impaired cognition and quality of life are significant phenomena in the late stages of CKD. We sought to obtain an overview and the attributable effect of impaired glomerular filtration on multiple domains in cognition and dimensions of quality of life for community-based healthy older adults in Taiwan.

Methods

The study was derived from the Nutrition and Health Survey in Taiwan (NAHSIT) 2013–2016, a nationwide cross-sectional study conducted to sample healthy, community-based older adults aged ≥65 years in Taiwan. Participants were categorized into four CKD groups: CKD stage 1, stage 2, stages 3a and 3b, and stages 4–5. The Mini-Mental State Examination (MMSE) and the QoL questionnaire derived from the 12-item Short Form Health Survey (SF-12) were measured. Generalized linear mixed models (GLMMs) and principal component regressions were employed for the analysis and validation, respectively.

Results

Participants with moderate CKD (stages 3a and 3b) showed deficits in global MMSE, domain orientation to time, calculation, complex commands, and role-physical and vitality in QoL questionnaires. In GLMMs, impaired eGFR per 30 mL/min/1.73 m² was associated with lower global MMSE scores (β = -0.807, standard error [SE] = 0.235, P = 0.0007), domain orientation to time (β = -0.155, SE = 0.047, P = 0.0011), calculation (β = -0.338, SE = 0.109, P = 0.0020), complex commands (β = -0.156, SE = 0.079, P = 0.0494), and role-physical (β = -2.219, SE = 0.779, P = 0.0046) dimensions of QoL.

Conclusions

Elderly Han Chinese adults with moderately impaired renal filtration could manifest cognitive deficits in orientation to time, calculation, and impaired quality of life in physical role functioning.

Retinal Neurovascular Impairment in Non-diabetic and Non-dialytic Chronic Kidney Disease Patients

Background: Widespread neural and microvascular injuries are common in chronic kidney disease (CKD), increasing risks of neurovascular complications and mortality. Early detection of such changes helps assess the risks of neurovascular complications for CKD patients. As an extension of central nervous system, the retina provides a characteristic window to observe neurovascular alterations in CKD. This study aimed to determine the presence of retinal neurovascular impairment in different stages of CKD. Methods: One hundred fifteen non-diabetic and non-dialytic CKD patients of all stages and a control group of 35 healthy subjects were included. Retinal neural and microvascular parameters were obtained by optical coherence tomography angiography (OCTA) examination. Results: CKD 1-2 group (versus control group) had greater odds of having decreased retinal ganglion cell-inner plexiform layer thickness (GC-IPLt) (odds ratio [OR]: 0.92; 95% confidence interval [CI]: 0.86-0.98), increased ganglion cell complex-focal loss volume (GCC-FLV) (OR: 3.51; 95% CI: 1.27-9.67), and GCC-global loss volume (GCC-GLV) (OR: 2.48; 95% CI: 1.27-4.82). The presence of advanced stages of CKD (CKD 3-5 group versus CKD 1-2 group) had greater odds of having decreased retinal vessel density in superficial vascular plexus (SVP)-WholeImage (OR: 0.77, 95% CI: 0.63-0.92), SVP-ParaFovea (OR: 0.83, 95% CI: 0.71-0.97), SVP-ParaFovea (OR: 0.76, 95% CI: 0.63-0.91), deep vascular plexus (DVP)-WholeImage (OR: 0.89, 95% CI: 0.81-0.98), DVP-ParaFovea (OR: 0.88, 95% CI: 0.78-0.99), and DVP-PeriFovea (OR: 0.90, 95% CI: 0.83-0.98). Besides, stepwise multivariate linear regression among CKD patients showed that β2-microglobulin was negatively associated with GC-IPLt (β: -0.294; 95% CI: -0.469 ∼ -0.118), and parathyroid hormone was positively associated with increased GCC-FLV (β: 0.004; 95% CI: 0.002∼0.006) and GCC-GLV (β: 0.007; 95% CI: 0.004∼0.01). Urine protein to creatinine ratio was positively associated with increased GCC-FLV (β: 0.003; 95% CI: 0.001∼0.004) and GCC-GLV (β: 0.003; 95% CI: 0.001∼0.006). Conclusion: Retinal neuronal impairment is present in early stages of CKD (stages 1-2), and it is associated with accumulation of uremic toxins and higher UACR, while retinal microvascular hypoperfusion, which is associated with worse eGFR, was only observed in relatively advanced stages of CKD (stages 3-5). The results highlight the importance of monitoring retinal neurovascular impairment in different stages of CKD.

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.

Association of brain white matter lesions and atrophy with cognitive function in chronic kidney disease

OBJECTIVES

Cognitive impairment is common in patients with chronic kidney disease (CKD), possibly leading to poor outcomes. However, the correlation between brain structural abnormalities and cognitive impairment remains unclear. The aim of this study was to investigate the impairment of specific cognitive domains and their association with brain structural abnormalities.

METHODS

Patients with CKD of at least stage 3 who were not on hemodialysis were enrolled. All participants underwent comprehensive neuropsychological testing in five cognitive domains. Ventricular atrophy, sulcal atrophy, medial temporal atrophy, and white matter changes were assessed using brain magnetic resonance imaging according to standard protocols.

RESULTS

Eighty-seven patients and 50 controls were enrolled. Patients with CKD exhibited decreased cognitive function relative to controls. Compared with patients with stage 3 CKD, those with advanced stage (stages 4 or 5) had poorer cognitive performance, more pronounced white matter hyperintensity (WMH) and more severe ventricular atrophy. Among CKD patients, executive function (β = -.23, P = .043) and attention (β = -.29, P = .004) were associated with WMH in controlled analyses. However, no cognitive impairment was associated with ventricular atrophy.

CONCLUSION

Patients with CKD exhibited cognitive impairment and brain structural abnormalities including WMH and general brain atrophy. Impairment of attention and executive dysfunction were associated with WMH.

Quantifying cognitive dysfunction across the spectrum of end-stage kidney disease: A systematic review and meta-analysis

Cognitive dysfunction is reportedly highly prevalent among chronic kidney disease (CKD) patients. A variety of screening tools and neuropsychiatric batteries are used to quantify the magnitude and nature of this dysfunction. Our objective is to summarize the neurocognitive testing used, and determine what degree cognitive dysfunction is reported in CKD patients. All study designs published in English that contained participants who were either pre-dialysis patients, haemodialysis (HD) or peritoneal dialysis (PD) patients or renal transplant recipients were considered. Reported comparative non-CKD control data was also collected. All study designs were included. The search period encompassed articles from 1980 to May 2018. This review is registered with PROSPERO (CRD42018096568). Of the 1711 articles screened, 148 articles were relevant and used in the meta-analysis. Commonly used assessments were The Mini-Mental State Examination (MMSE), The Modified Mini-Mental State Examination, the Trails Making Tests (TMT) forms A and B and components of the Wechsler Adult Intelligence Scale: Digit Span and Digit Symbol. Means for all assessments were adjusted using a random effects model to account for the differences in variance. Adjusted mean MMSE scores were significantly lower for both pre-dialysis (26.08, n = 17 073) and HD (26.31, n = 3314) patients when compared to non-CKD controls (28.21, n = 5226). PD (58.01 s, n = 859) and HD (56.04 s, n = 2344) patients also took significantly longer to complete the Trails Making Task A than non-CKD controls (37.62 s, n = 4809). Patients with CKD, especially pre-dialysis and those requiring dialysis, are likely to exhibit impairments in cognition that can be identified with specific screening neuropsychological assessments.

A Systematic Review of Cognitive Impairments Associated With Kidney Failure in Adults Before Natural Age-Related Changes

OBJECTIVES

Recognition of cognitive impairment in chronic kidney disease (CKD) and its impact on functioning in adults is growing. The vast majority of studies to date have been conducted in older populations where CKD is more pronounced; however, the degree to which age-related cognitive changes could be influencing these findings remains unaddressed. This current study thus aimed to review cognitive impairment findings by stage in non-elderly CKD samples.

METHODS

PubMed and Medline via Scopus were searched for cross-sectional or cohort studies and randomized controlled trials that assessed cognitive function in individuals with CKD in any research setting. CKD studies including patients at any illness stage were included providing participants were below 65 years old, were not on peritoneal dialysis and had not undergone a kidney transplant.

RESULTS

Fifteen studies, with a total of 9304 participants, were included. Cognitive function broadly deteriorated from stage 1 to stage 5. Early stage CKD was associated with a drop in speed of processing, attention, response speed, and short-term memory abilities. Moderate stage CKD was associated with deficits in executive functioning, verbal fluency, logical memory, orientation and concentration. People with end stage kidney disease manifested significant deficits in all previous cognitive domains, along with cognitive control, delayed and immediate memory, visuospatial impairment, and overall cognitive impairment.

CONCLUSIONS

Cognitive impairment is evident across the stages of CKD, independent of age-related changes, for both lower-order and higher-order cognitive abilities. These impairments also increase between the stages, suggesting a cumulative effect. Future directions for research are discussed. (JINS, 2019, 25, 101-114).

Cognitive impairment and hippocampal atrophy in chronic kidney disease

BACKGROUND

Cognition impairment is well known in patients with chronic kidney disease (CKD). The relationship between brain structure and cognitive performance in CKD patients is still under investigation. The study aimed to quantitatively assess the relationship between brain structure and cognitive performance in patients with CKD.

METHODS

We recruited 39 patients with CKD and 39 age- and sex-matched control participants from a tertiary medical center. All participants underwent 3-T MRI scan neuropsychological assessments, and renal function tests. FreeSurfer software was used for imaging processing and analysis, including measurement of cortical thickness and gray matter (GM) and white matter volumes.

RESULTS

Compared with control subjects (73.1±7.5 years old), patients with CKD (76.4±8.4 years old) had significantly lower scores on the Mini-Mental State Examination, and forward digit span test (P<.01). Patients with CKD had smaller cerebral GM volume, hippocampus, and decreased cortical thickness (P<.01) relative to the control group. Estimated glomerular filtration rate (eGFR) was correlated with cognitive performance, cortical thickness, GM volume, and hippocampal volume (P<.001). Linear regression analysis revealed that eGFR and GM volume were independently negatively associated with cognitive performance (P<.001), while eGFR and age were negatively associated with cortical thinning and GM volume after controlling for confounding factors.

CONCLUSIONS

This study demonstrated that impaired kidney function is associated not only with poor cognitive performance, but also with small cerebral GM volume and reduced cortical thickness.

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 of homocysteine level and vascular burden and cognitive function in middle-aged and older adults with chronic kidney disease

OBJECTIVES

Patients with chronic kidney disease (CKD) have been found to have cognitive impairment. However, the core features and clinical correlates of cognitive impairment are still unclear. Elevated homocysteine levels are present in CKD, and this is a risk factor for cognitive impairment and vascular diseases in the general population. Thus, this study investigated the core domains of cognitive impairment and investigated the associations of homocysteine level and vascular burden with cognitive function in patients with CKD.

METHODS

Patients with CKD aged ≥ 50 years and age- and sex-matched normal comparisons were enrolled. The total fasting serum homocysteine level was measured. Vascular burden was assessed using the Framingham Cardiovascular Risk Scale. Cognitive function was evaluated using comprehensive neuropsychological tests.

RESULTS

A total of 230 patients with CKD and 92 comparisons completed the study. Memory impairment and executive dysfunction were identified as core features of cognitive impairment in the CKD patients. Among the patients with CKD, higher serum homocysteine levels (β = -0.17, p = 0.035) and higher Framingham Cardiovascular Risk Scale scores (β = -0.18, p = 0.013) were correlated with poor executive function independently. However, an association with memory function was not noted. Our results showed that an elevated homocysteine level and an increased vascular burden were independently associated with executive function, but not memory, in CKD patients.

CONCLUSIONS

This findings suggested the co-existence of vascular and non-vascular hypotheses regarding executive dysfunction in CKD patients. Meanwhile, other risk factors related to CKD itself should be investigated in the future. Copyright © 2015 John Wiley & Sons, Ltd.

Estimated GFR, Albuminuria, and Cognitive Performance: The Maastricht Study

BACKGROUND

Reduced estimated glomerular filtration rate (eGFR) and albuminuria have been associated with worse cognitive performance. However, few studies have examined whether these associations are confined to older individuals or may be extended to the middle-aged population.

STUDY DESIGN

Cross-sectional analyses of a prospective population-based cohort study.

SETTING & PARTICIPANTS

2,987 individuals aged 40 to 75 years from the general population (The Maastricht Study).

PREDICTOR

eGFR and urinary albumin excretion (UAE).

OUTCOMES

Memory function, information processing speed, and executive function.

MEASUREMENTS

Analyses were adjusted for demographic variables (age, sex, and educational level), lifestyle factors (smoking behavior and alcohol consumption), depression, and cardiovascular disease risk factors (glucose metabolism status, waist circumference, total to high-density lipoprotein cholesterol ratio, triglyceride level, use of lipid-modifying medication, systolic blood pressure, use of antihypertensive medication, and prevalent cardiovascular disease).

RESULTS

UAE was <15mg/24 h in 2,439 (81.7%) participants, 15 to <30 mg/24 h in 309 (10.3%), and ≥30mg/24 h in 239 (8.0%). In the entire study population, UAE≥30mg/24 h was associated with lower information processing speed as compared to UAE<15mg/24 h (β [SD difference] = -0.148; 95% CI, -0.263 to -0.033) after full adjustment, whereas continuous albuminuria was not. However, significant interaction terms (P for interaction < 0.05) suggested that albuminuria was most strongly and extensively associated with cognitive performance in older individuals. Mean (±SD) eGFR, estimated by the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine-cystatin C equation (eGFR_cr-cys), was 88.4±14.6 mL/min/1.73m². eGFR_cr-cys was not associated with any of the domains of cognitive performance after full adjustment. However, significant interaction terms (P for interaction < 0.05) suggested that eGFR_cr-cys was associated with cognitive performance in older individuals.

LIMITATIONS

Cross-sectional design, which limited causal inferences.

CONCLUSIONS

In the entire study population, albuminuria was independently associated with lower information processing speed, whereas eGFR_cr-cys was not associated with cognitive performance. However, both were more strongly and extensively associated with cognitive performance in older individuals.

Indoxyl sulfate, not p-cresyl sulfate, is associated with cognitive impairment in early-stage chronic kidney disease

BACKGROUNDS

Patients with chronic kidney disease (CKD) more commonly experience cognitive impairment, but the etiologies are not clear. Uremic toxins such as p-cresyl sulfate (PCS) and indoxyl sulfate (IS) have been shown to increase the risks of cardiovascular diseases and mortality; however, no study has investigated the associations of PCS and IS with cognitive function in patients with CKD.

METHODS

Patients with CKD aged ≥50 years and age- and sex-matched non-CKD comparison subjects were recruited. CKD stage was defined according to the National Kidney Foundation guidelines. Cognitive function was evaluated using comprehensive neuropsychological tests. The associations between uremic toxins and cognitive function domains were examined using multiple linear regression analysis. The interaction between uremic toxins and CKD stages on cognitive functions were also examined.

RESULTS

In total, 199 patients with CKD and 84 comparison subjects completed the study. The patients with CKD had poorer cognitive function and higher serum PCS and IS levels. A higher serum IS level was associated with poor executive function (β=-0.31, P=0.003) only in stage 3 CKD patients after adjustment for age, sex and educational level. Serum PCS level was not associated with cognitive function in patients with CKD.

CONCLUSIONS

Our study showed that a higher serum IS level was associated with poor executive function in the early stage of CKD. It would be worthwhile to investigate the effect of IS removal in early-stage CKD on the prevention of cognitive impairment in future studies.

Climacteric symptoms in middle-aged women with chronic somatic diseases

OBJECTIVES

Chronic diseases may aggravate or simulate climacteric symptoms. Although acknowledged in clinical practice, there is a lack of research systematically analysing the association between chronic diseases and climacteric symptoms.

STUDY DESIGN AND MAIN OUTCOME MEASURES

Our study was a cross-sectional population-based study, which included 3421 women, aged 41-54 years. Climacteric symptoms were evaluated using the Women's Health Questionnaire (WHQ), of which we included seven symptom domains (vasomotor, sleep, depressive, anxiety/fears, cognitive, sexual, and menstrual) and a question concerning whether the women were worried about growing old. The occurrence of various diseases (cardiovascular, neurological, sensory organ, bronchopulmonary, musculoskeletal, gastrointestinal, urological, dermatological, and thyroid disease, diabetes, and cancer) was recorded. The associations between the diseases and symptoms were defined with multivariable analyses, adjusting for various confounding factors.

RESULTS

The women with the diseases had more symptoms. Vasomotor symptoms and sleep problems were associated only with gastrointestinal diseases, and lower sexual functioning only with diabetes. The remaining symptoms were associated with several diseases, except being worried about growing old, which was not associated with any.

CONCLUSIONS

Many symptoms connected to the climacteric may manifest also due to chronic diseases. Thus, health-care professionals should consider the origin of the symptoms when treating middle-aged women with chronic diseases.

Mild chronic kidney disease is associated with cognitive function in patients presenting at a memory clinic

OBJECTIVE

In dialysis-dependent and severe chronic kidney disease (CKD) patients, cognitive impairment is found in 16-29%. In community-dwelling population without dementia mixed results have been observed. We investigated the relationship between renal function and cognition in patients from a memory clinic.

METHODS

We performed a cross-sectional study of consecutive patients from a memory clinic between 2005 and 2009. Renal function was estimated with the Modification of Diet in Renal Diseases (MDRD) and Cockcroft-Gault (CG) formulas, and categorized into ordinal groups: reference ≥ 60 ml/min/1.73 m(2), mild CKD 45-59 ml/min/1.73 m(2) and moderate CKD <45 ml/min/1.73 m(2). Cognitive function was dichotomized (Mini-Mental State Examination (MMSE) ≥ 24 vs. <24). We performed multiple logistic regression analyses with adjustment for potential confounders.

RESULTS

The cohort comprised 581 patients (mean age 77 ± 10 years). With the MDRD, there were 74 (12%) cases with moderate CKD and 108 (18%) with mild CKD. With the CG, these prevalences were 144 (30%) and 130 (27%). In mild CKD patients, a significant relationship was found between cognitive function and CKD according to the MDRD-formula [adjusted OR 2.10; 95%CI 1.09-4.05]. In moderate CKD patients, no significant adjusted associations were found. In patients without dementia, significant adjusted associations were found between CKD and MMSE (MDRD: mild CKD [OR 5.09; 95%CI 1.17-22.14] and moderate CKD [OR 5.03; 95%CI 1.10-22.98]; CG: mild CKD [OR 6.16; 95%CI 1.17-32.50] and moderate CKD [OR 5.60; 95%CI 1.01-30.91]).

CONCLUSION

This study showed a significant association between mild CKD and impaired cognitive function in patients from a memory clinic, especially in patients without dementia.

The extent of informed decision-making about starting dialysis: does patients' age matter?

BACKGROUND

A growing number of elderly patients with end-stage renal disease start dialysis. We examined elderly (≥65 years) patients' views about their decision-making experience after starting dialysis in comparison with patients aged 50-64 years, and patients ≤49 years.

METHODS

Ninety-nine patients from 15 outpatient dialysis centers in North Carolina, USA completed a semi-structured interview asking them about the context of decision-making and their decision-making experience, and a 10-item investigator-developed Informed Decision-Making (IDM) questionnaire with binary response options (yes/no).

RESULTS

While IDM scores were low for all three groups (<5 out of 10), they were significantly lower for the older group compared to the other two younger groups (p = 0.02). A significantly lower percentage of the older group said that the doctor explained underlying conditions that led to kidney failure (p = 0.04), the impact of dialysis on daily life (p = 0.04), and the life-long need for dialysis (p < 0.01), and that the doctor tried to make sure the patient understood the information (p = 0.01). Also a significantly higher percentage of elderly patients felt the decision was made by the doctor rather than on their own or with their family, or collaboratively with the doctor (p = 0.04).

CONCLUSIONS

Informed decision-making is significantly poorer in patients aged 65 years or older than in younger patients. Clinicians should communicate clearly about the benefits and burdens of dialysis to older adults and provide an opportunity for them to understand the significant trade-offs that dialysis may require.

Relationship of subjective cognitive impairment and cognitive impairment no dementia to chronic disease and multimorbidity in a nation-wide twin study

We investigated the relation of subjective cognitive impairment (SCI) and cognitive impairment no dementia (CIND) to common chronic diseases of the elderly and multimorbidity, and assessed the contribution of genetic background and shared familial environment to these associations. Subjects were 11,379 dementia-free twin individuals aged ≥ 65 from the Swedish Twin Registry. SCI was defined as subjective complaint of cognitive change without objective cognitive impairment and CIND was defined according to current criteria. In unmatched, fully-adjusted regression models, mental, musculoskeletal, respiratory, and urological diseases were all significantly associated with increased odds ratios (ORs) of SCI and CIND. Circulatory and gastrointestinal diseases were related to SCI only, while endocrine diseases were associated with CIND. The adjusted ORs of multimorbidity were 2.1 [95% confidence intervals (95% CI): 1.8-2.3] for SCI and 1.5 for CIND (95% CI: 1.3-1.8). A dose-dependent relationship was observed between number of chronic diseases and ORs for SCI but not for CIND. In co-twin control analyses, the chronic diseases-SCI association was largely unchanged. On the other hand, the chronic diseases-CIND association was no longer statistically significant, except for cancer, where an increased OR was observed. In conclusion, chronic morbidity is associated with both SCI and CIND but disease profiles do not always overlap between the two cognitive syndromes. The association is stronger when diseases co-occur, especially for SCI. Genetic and early-life environmental factors may partially explain the association of CIND but not that of SCI with chronic diseases.

Patient perspectives on informed decision-making surrounding dialysis initiation

BACKGROUND

Careful patient-clinician shared decision-making about dialysis initiation has been promoted, but few studies have addressed patient perspectives on the extent of information provided and how decisions to start dialysis are made.

METHODS

Ninety-nine maintenance dialysis patients recruited from 15 outpatient dialysis centers in North Carolina completed semistructured interviews on information provision and communication about the initiation of dialysis. These data were examined with content analysis. In addition, informed decision-making (IDM) scores were created by summing patient responses (yes/no) to 10 questions about the decision-making.

RESULTS

The mean IDM score was 4.4 (of 10; SD = 2.0); 67% scored 5 or lower. Age at the time of decision-making (r = -0.27, P = 0.006), years of education (r = 0.24, P = 0.02) and presence of a warning about progressing to end-stage kidney disease (t = 2.9, P = 0.005) were significantly associated with IDM scores. Nearly 70% said that the risks and burdens of dialysis were not mentioned at all, and only one patient recalled that the doctor offered the option of not starting dialysis. While a majority (67%) said that they felt they had no choice about starting dialysis (because the alternative would be death) or about dialysis modality, only 21.2% said that they had felt rushed to make a decision. About one-third of the patients perceived that the decision to start dialysis and modality was already made by the doctor.

CONCLUSIONS

A majority of patients felt unprepared and ill-informed about the initiation of dialysis. Improving the extent of IDM about dialysis may optimize patient preparation prior to starting treatment and their perceptions about the decision-making process.

Use of secondary prevention medications among adults with reduced kidney function

BACKGROUND AND OBJECTIVES

Persons with kidney disease often have cardiovascular disease, but they are less likely to use recommended medications for secondary prevention. The hypothesis was that participants with reduced estimated GFR have lower use of medications recommended for secondary prevention of cardiovascular events (antiplatelet agents, angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, β-blockers, and statins) and lower medication adherence than participants with preserved estimated GFR.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this cross-sectional analysis, we analyzed data from 6913 participants in the Reasons for Geographic and Racial Differences in Stroke study with a history of cardiovascular disease. Medication use was ascertained by an in-home pill bottle review. Medication adherence was assessed using a validated four-item scale.

RESULTS

Among participants with a history of cardiovascular disease, 59.8% used antiplatelet agents, 49.9% used angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, 41.6% used β-blockers, and 53.0% used statins. Compared with the referent group (estimated GFR ≥60 ml/min per 1.73 m(2)), participants with estimated GFR <45 ml/min per 1.73 m(2) were more likely to use angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers (adjusted prevalence ratio=1.14, 95% confidence interval=1.06-1.23), β-blockers (adjusted prevalence ratio=1.20, 95% confidence interval=1.09-1.32), and statins (adjusted prevalence ratio=1.10, 95% confidence interval=1.01-1.19). Antiplatelet agent use did not differ by estimated GFR category; 30% of participants reported medication nonadherence across all categories of estimated GFR.

CONCLUSIONS

Among participants with a history of cardiovascular disease, mild to moderate reductions in estimated GFR were associated with similar and even more frequent use of medications for secondary prevention compared with participants with preserved estimated GFR. Overall medication use and adherence were suboptimal.

Is chronic kidney disease in older people a new geriatric giant?

The global population is aging, and the number of people above the age of 85 years is growing faster than any other age group. There is an age-related decline in kidney function; however, not all individuals will develop chronic kidney disease (CKD) with advancing age. Those who are genetically predisposed and exposed to lifetime cardiovascular risk factors are likely to develop systemic atherosclerosis and CKD as a part of its manifestation. CKD promotes poor health through its association with inflammation and oxidative stress. Malnutrition, weight loss and sarcopenia are common in CKD patients, leading to poor outcomes, such as physical and cognitive dysfunction, manifesting as major geriatric syndromes. Frailty is likely to be one of the underlying processes that leads to the clinical manifestations of geriatric syndromes in patients with CKD. Therefore, functional outcomes, such as cognition and physical functioning, might be more relevant outcomes to older patients with CKD. Interventions should be developed and assessed in terms of maintaining quality rather than quantity of life before disability develops.

Chronic kidney disease, 24-h blood pressure and small vessel diseases are independently associated with cognitive impairment in lacunar infarct patients

Although the relationships between chronic kidney disease (CKD) and cognitive impairment (CI) have been highlighted, the etiology of CI in CKD remains uncertain. Subjects comprised 224 consecutive patients with symptomatic lacunar infarction who underwent magnetic resonance imaging and ambulatory blood pressure monitoring (ABPM). Diurnal blood pressure (BP) patterns were categorized into three groups: dippers, non-dippers and risers. Lacunar infarcts (LIs), including both symptomatic and silent and diffuse white matter lesions (WMLs), were graded into three grades according to their degree. The results of kidney function were evaluated using estimated glomerular filtration rate (eGFR), categorized into three groups: stage 1, >60; stage 2, 30-60; and stage 3, <30 ml min(-1) per 1.73 m(2). There were 44 patients with CI. Confluent WMLs, including WML 2 and WML 3, were found in 36 patients (81.8%), and multiple lacunae including LI 2 and LI 3 were found in 30 patients (68.1%) with CI. Age >75 years (odds ratio (OR), 5.5; P<0.05), male sex (OR, 2.8; P<0.05), non-dippers (OR, 6.3; P<0.05) and risers (OR, 5.6; P<0.05), eGFR 30-60 ml min(-1) per 1.73 m(2) (OR, 2.9; P<0.05) and eGFR <30 ml min(-1) per 1.73 m(2) (OR, 23.8; P<0.01), WML grade 2 (OR, 5.1; P<0.01) and WML grade 3 (OR, 45.2; P<0.001) and LI grade 2 (OR, 3.2; P<0.05) and LI grade 3 (OR, 6.4; P<0.05) were independently associated with CI. Age >75 years (OR, 4.1; P<0.05), eGFR 30-60 ml min(-1) per 1.73 m(2) (OR, 3.7; P<0.05) and eGFR <30 ml min(-1) per 1.73 m(2) (OR, 8.7; P<0.05) were independently associated with WML grade 3. Extensive small vessel diseases, CKD and non-dipping status were independently associated with CI. CKD appears to mainly contribute to vascular CI, whereas possibilities of overlapping with other mechanisms such as degenerative CI cannot be excluded. Strict night time BP control and renoprotective treatment may be warranted to prevent CI.

Continuous cognitive improvement 1 year following successful kidney transplant

Successful kidney transplantation was recently shown to lead to improvement in the cognitive performance of patients on chronic dialysis. To examine whether the early cognitive benefits of transplantation continue to develop over time, along with the patients' ongoing recovery, we addressed these questions in a prospective controlled study of 27 dialyzed patients who subsequently received a kidney transplant, 18 dialyzed patients awaiting kidney transplant, and 30 matched controls without kidney disease. Overall, successful kidney transplant contributed to a statistically significant improvement in performance on tests of motor/psychomotor speed, visual planning, memory, and abstract reasoning tested 1 year later. We also studied whether the cognitive performance of patients maintained on dialysis is stable or declines over time and found that it actually declined over this time even in adequately dialyzed patients. Measures of memory functions were particularly affected. This study indicates that the early beneficial effects of transplantation are not transient and were still evident 1 year following transplantation.

Kidney function and long-term medication adherence after myocardial infarction in the elderly

BACKGROUND AND OBJECTIVES

The association of kidney function with long-term outpatient medication adherence in the elderly remains understudied.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A cohort of 2103 patients over the age of 65 years enrolled in a pharmacy benefits program after hospital discharge for myocardial infarction was studied. Using linear mixed effects models, the association of baseline kidney function with long-term adherence to recommended medications after myocardial infarction was examined, including angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs), β-blockers, and statins. The primary outcome measure was the percentage of days covered as calculated by pharmacy refill data for 12 serial 3-month intervals (totaling 36 months of follow-up).

RESULTS

Overall long-term adherence to ACEIs/ARBs, β-blockers, and statins was poor. The mean percentage of days covered by 36 months was only 50% to 60% for all three medication classes. Patients with baseline kidney dysfunction had significantly lower long-term ACEI/ARB and β-blocker adherence compared with patients with higher baseline kidney function. Long-term statin adherence did not vary by baseline level of kidney function.

CONCLUSIONS

Long-term medication adherence after myocardial infarction in the elderly is low, especially in patients with kidney dysfunction. Future strategies to improve medication adherence should pay special attention to the elderly with kidney dysfunction because they may be especially vulnerable to its adverse clinical consequences.

Association of CKD with disability in the United States

BACKGROUND

Little is known about disability in early-stage chronic kidney disease (CKD).

STUDY DESIGN

Cross-sectional national survey (National Health and Nutrition Examination Survey 1999-2006).

SETTING & PARTICIPANTS

Community-based survey of 16,011 noninstitutionalized US civilian adults (aged ≥20 years).

PREDICTOR

CKD, categorized as no CKD, stages 1 and 2 (albuminuria and estimated glomerular filtration rate [eGFR] ≥60 mL/min/1.73 m²), and stages 3 and 4 (eGFR, 15-59 mL/min/1.73 m²).

OUTCOME

Self-reported disability, defined by limitations in working, walking, and cognition and difficulties in activities of daily living (ADL), instrumental ADL, leisure and social activities, lower-extremity mobility, and general physical activity.

MEASUREMENTS

Albuminuria and eGFR assessed from urine and blood samples; disability, demographics, access to care, and comorbid conditions assessed using a standardized questionnaire.

RESULTS

Age-adjusted prevalence of reported limitations generally was significantly greater with CKD: for example, difficulty with ADL was reported by 17.6%, 24.7%, and 23.9% of older (≥65 years) and 6.8%, 11.9%, and 11.0% of younger (20-64 years) adults with no CKD, stages 1 and 2, and stages 3 and 4, respectively. CKD also was associated with greater reported limitations and difficulty in other activities after age adjustment, including instrumental ADL, leisure and social activities, lower-extremity mobility, and general physical activity. Other demographics, socioeconomic status, and access to care generally only slightly attenuated the observed associations, particularly in older individuals; adjustment for cardiovascular disease, arthritis, and cancer attenuated most associations such that statistical significance no longer was achieved.

LIMITATIONS

Inability to establish causality and possible unmeasured confounding.

CONCLUSION

CKD is associated with a higher prevalence of disability in the United States. Age and other comorbid conditions account for most, but not all, of this association.