Kidney function and cognitive impairment in US adults: the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study

Kidney function and cognitive impairment: a systematic review and meta-analysis

BACKGROUND

A worldwide evaluation exploring the link between a broad-spectrum kidney function and cognitive impairment (CI) prevalence, and related risk factors has yet to be conducted.

METHODS

Studies published before November 2024 were retrieved from PubMed and Web of Science. R software (R Foundation for Statistical Computing, Vienna, Austria) and Review Manager (Cochrane Collaboration, London, UK) were used to analyze the relationship of CI with various estimated glomerular filtration rate (eGFR) level and the associated risk factors. A random model effect was adopted for a heterogeneity (I2) of more than 50%.

RESULTS

Seventeen (involving 32,141 participants) out of 5892 studies were included. The MMSE and MoCA were the most commonly used tests to assess cognitive function. The prevalence of CI raised significantly with declining kidney function: 10% for eGFR ≥60 mL/min/1.73 m2, 47.3% for 60-30 mL/min/1.73 m2, and 60.6% for <30 mL/min/1.73 m2, totaling 16.7% overall. Thirteen potential risk factors were ascertained and analyzed. In the forest-plot analysis, T2DM, cardiovascular diseases, cerebrovascular diseases, and lower education emerged as strong predictors of risk, with odds ratios of 1.55, 1.63, 1.95, and 2.59, respectively. A mean meta-analysis of the continuous variable indicators revealed that advanced age and elevated parathyroid hormone (PTH) levels were statistically significant in the occurrence of CI.

CONCLUSIONS

The poorer the renal function, the higher the prevalence rate of CI. Patients with chronic kidney disease (CKD) have multiple risk factors that lead to CI.

Development of Machine-Learning-Based Models for Detection of Cognitive Impairment in Patients Receiving Maintenance Hemodialysis

BACKGROUND

Cognitive impairment is common but frequently undiagnosed in the dialysis population. We aimed to develop and validate a quick and accurate screening tool using machine-learning-based approaches in them.

METHODS

In this cross-sectional observational study, we administered the Mini-Mental State Examination (MMSE) and Cognitive Abilities Screening Instrument (CASI) in 508 hemodialysis patients and randomly divided them into a derivation set (70%) and a validation set (30%). Using three to five key items from MMSE and CASI as predictors, we developed six machine learning models, including Lasso, classification and regression tree (CART), random forest (RF), extreme gradient boosting, support vector machine (SVM), and artificial neural networks to identify those with a CASI score below the 20th percentile of age- and education-matched norms in the derivation set. We then evaluated the predictive performance of these models in the validation set.

RESULTS

The derivation samples (n = 357) had a mean (SD) age of 64.13 (11.92) years and a mean education level of 8.76 (4.91) years. Around 40% of participants had a CASI score below the 20th percentile. Among all models, the RF model achieved the highest performance of prediction, with an accuracy of 0.94, an area under the curve (AUC) of 0.95, and an F1 score of 0.92 in the validation set. The other models, except for CART, performed equally well in terms of AUC.

CONCLUSIONS

Our study demonstrates that using machine-learning models, we can identify patients with impaired cognition with only several questions in CASI and MMSE within 5 min.

Plasma concentrations of neurofilament light, p-Tau231 and glial fibrillary acidic protein are elevated in patients with chronic kidney disease and correlate with measured glomerular filtration rate

BACKGROUND

Patients with chronic kidney disease (CKD) have a high prevalence of cerebrovascular disease and cognitive impairment. The objective was to analyse whether plasma concentrations of neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP) and phosphorylated Tau231 (p-Tau231) are elevated in patients with CKD and to identify independent predictors of these biomarkers, with an emphasis on the role of measured glomerular filtration rate (mGFR).

METHODS

In this cross-sectional cohort study, we included 110 patients with CKD stages 3 and 4 (estimated GFR 15-59 ml/min/1.73 m2) without manifest cerebrovascular disease or dementia, and 55 healthy controls. Biomarkers of neurological disorders were measured with ultrasensitive single molecule array methods.

RESULTS

Plasma concentrations (median [IQR]) of NfL (37.5 [22.1-47.5] vs. 13.4 [10.5-16.7] ng/L, p < 0.001), p-Tau231 (25.7 [19.1-38.7] vs. 13.9 [10.5-16.3] ng/L, p < 0.001) and GFAP (190 [140-281] vs. 153 [116-211] ng/L, p < 0.001) were elevated in patients with CKD vs. controls. Measured GFR was negatively correlated with NfL (r = - 0.706, p < 0.001), p-Tau231 (r = - 0.561, p < 0.001), and GFAP (r = - 0.385, p < 0.001). In multivariable linear regression models, mGFR was an independent predictor of log-transformed plasma concentrations of NfL (standardized beta coefficient [β] = - 0.439, p < 0.001) and GFAP (β = - 0.321, p < 0.001).

CONCLUSION

Patients with CKD had elevated plasma concentrations of NfL, p-Tau231 and GFAP compared with controls, and these biomarkers were inversely correlated with mGFR. Measured GFR was a significant, independent predictor of plasma concentrations of NfL and GFAP in patients with CKD. The mechanisms underlying this association need further investigation. Plasma levels of NfL and GFAP should be interpreted cautiously in patients with marked reductions in GFR.

Identifying Research Priorities for Cognition in CKD: A Delphi Study

Key Points

Background

Cognition is a research priority for people living with CKD, but identification of critical research questions is lacking. This study aimed to determine which cognition-related research questions are most important to CKD stakeholders.

Methods

A modified Delphi technique with three survey rounds was used. The study sample included three panels (People with lived CKD experience, Researchers, and Clinicians) recruited through international patient and kidney research networks, kidney societies, and snowball sampling with email invitations. Survey rounds were distributed electronically through Research Electronic Data Capture. In round 1 (October 2021–May 2022), respondents contributed three important research questions regarding cognition in CKD (free text). After deduplication and qualitative synthesis, respondents ranked the importance of these questions on a nine-point Likert scale in round 2 (February–April 2023). Questions with mean and median ratings of >7 by at least two respondent panels or rated critically important by the lived experience panel were reranked in round 3 (August–September 2023) and assessed for consensus to identify the final list of priority research questions.

Results

Respondents (n=152) identified 125 and 44 discrete questions after rounds 1 and 2, respectively. The final shortlist included 27 questions in eight categories. The most critical research question identified was “What factors prevent cognitive impairment in people receiving dialysis?” Overall, respondents prioritized questions focusing on prevention and treatment of cognitive impairment. Scores between the panels were significantly different for 16 questions. Those with lived CKD experience prioritized quality of life, researchers emphasized developing interventions to mitigate cognitive impairment, and clinicians prioritized the effect of CKD treatment on cognitive impairment.

Conclusions

Through an established consensus methodology involving key stakeholder groups, we identified 27 critical research questions about cognition in CKD. These questions should guide future study design and outcome selection.

Who should make the decision for renal replacement therapy?

INTRODUCTION

In this study, we aimed to evaluate cognitive functions in Stage 4 and 5 CKD patients using the Montreal Cognitive Assessment (MoCA) Scale, which objectively assesses cognitive dysfunction and various cognitive functions, and to compare them with a control group with normal kidney functions.

METHODS

All participants in our case-control study were administered the Montreal Cognitive Assessment (MoCA) Test, and total scores, subscale scores, and the presence of cognitive dysfunction were recorded.

RESULTS

When the groups were compared in terms of cognitive dysfunction (CD), 12.9% of the control group and 37.1% of the case group were found to have CD, which was statistically significant. When the groups were compared in terms of data and scale scores, the visual construction subscale score, naming, delayed recall subscale score, and total MoCA score were found to be significantly lower in the case group compared to the control group.

CONCLUSION

Our study is the first to use the MoCA test with the correct reference range. The significant impairment observed in the cognitive functions of patients with advanced-stage CKD in our study suggests that the decision for renal replacement therapy should not be made by the patient alone, as it may be incorrect.

Care pathways for patients with cognitive impairment and chronic kidney disease

Various epidemiological datasets and pathophysiological hypotheses have highlighted a significant link between chronic kidney disease (CKD) and cognitive impairment (CI); each condition can potentially exacerbate the other. Here, we review the mutual consequences of CKD and CI on health outcomes and care pathways and highlight the complexities due to the involvement of different specialists. Our narrative review covers (i) the burden of CI among patients with CKD, (ii) the impact of CI on kidney health, (iii) access to kidney replacement therapy for people with CI, (iv) resources in cognitive care and (v) potential models for integrated 'nephro-cognitive' care. CI (ranging from mild CI to dementia) has a significant impact on older adults, with a high prevalence and a strong association with CKD. Furthermore, CI complicates the management of CKD and leads to a higher mortality rate, poorer quality of life and higher healthcare costs. Due to difficulties in symptom description and poor adherence to medical guidelines, the presence of CI can delay the treatment of CKD. Access to care for patients with both CKD and CI is hindered by physical, cognitive and systemic barriers, resulting in less intensive, less timely care. Multidisciplinary approaches involving nephrologists, geriatricians, neurologists and other specialists are crucial. Integrated care models focused on person-centred approaches, shared decision-making and continuous co-management may improve outcomes. Future research should focus on the putative beneficial effects of these various strategies on both clinical and patient-reported outcomes.

Association of cystatin C kidney function measures with motoric cognitive risk syndrome: evidence from two cohort studies

BACKGROUND

This study aimed to examine the associations of cystatin C, cystatin C estimated glomerular filtration rate (eGFRcys), and the difference between eGFRs (eGFRdiff) using cystatin C and creatinine levels with incident motoric cognitive risk syndrome (MCR).

METHODS

We utilized data from two nationally representative cohort studies, the China Health and Retirement Longitudinal Study (CHARLS, 2011-2015) and the US Health and Retirement Study (HRS, 2010-2018). Baseline serum cystatin C and creatinine levels were measured, and eGFRcys and creatinine estimated GFR (eGFRcr) were calculated. MCR was defined as subjective cognitive complaints plus objectively measured slow gait speed. Multivariable logistic models were used to investigate the longitudinal associations between kidney function measurements and incident MCR.

RESULTS

In CHARLS (N = 2,085) and HRS (N = 1,240) cohorts, 7.4% and 7.2% developed MCR over follow-up. Each SD increment in serum cystatin C level was associated with elevated incident MCR odds, and an inverse association of eGFRcys with incident MCR was observed in both cohorts after multivariable adjustment and meta-analyses. The association between serum cystatin C and incident MCR remained significant even after adjusting for serum creatinine, suggesting that cystatin C is independently associated with MCR, regardless of kidney function levels. Additionally, each SD decrease in the absolute value of eGFRdiff was associated with lower odds of incident MCR among CHARLS participants.

CONCLUSIONS

Cystatin C and eGFRcys were correlated with an elevated MCR risk in two distinct populations. Specifically, eGFRdiff also related to incident MCR among Chinese older adults. Monitoring cystatin C-based kidney function could have significant clinical utility for identifying incident MCR risk, and represents a potential intervention target for healthier cognitive aging.

Fluid excess on intensive care unit after mechanical thrombectomy after acute ischemic stroke is associated with unfavorable neurological and functional outcomes: An observational cohort study

INTRODUCTION

Endovascular thrombectomy stands as a pivotal component in the standard care for patients experiencing acute ischemic stroke with large vessel occlusion. Subsequent care for patients often extends to a neurological intensive care unit. While fluid management is integral to intensive care, the association between early fluid balance and neurological and functional outcomes post-thrombectomy has not yet been thoroughly investigated.

METHODS

In a retrospective analysis of an observational, single-center study spanning from 2015 to 2021 at the University Medical Center Hamburg-Eppendorf, Germany, we enrolled stroke patients who underwent thrombectomy and received subsequent treatment in the ICU. Unfavorable functional and neurological outcome was defined as a mRS > 2 on day 90 after admission (mRS d90) or NIHSS > 5 at discharge, respectively. A multivariate regression model, adjusting for confounders, utilized the average fluid balance in the first 5 days to predict outcomes. Patients were dichotomized by their average fluid balance (>1 L vs <1 L) within the first 5 days, and a multivariate mRS d90 shift analysis was conducted after adjusting for covariates.

RESULTS

Between 2015 and 2021, 1252 patients underwent thrombectomy, and 553 patients met the inclusion criteria (299 women [54%]). Unfavorable functional outcome was significantly associated with a higher daily average fluid balance in the first 5 days in the ICU (mRS d90 ⩽ 2: 0.3 ± 0.5 L, mRS d90 > 2: 0.7 ± 0.7 L, p = 0.02). The same association was observed for the NIHSS at discharge (NIHSS ⩽ 5: 0.3 ± 0.5 L; NIHSS > 5: 0.6 ± 0.6 L; p = 0.03). The mRS d90 shift analysis revealed significance for patients with an average fluid balance <1 L for better functional outcomes (adjusted odds ratio [AOR] 2.17; 95% confidence interval [CI] 1.54-3.07; p < 0.01).

DISCUSSION

Fluid retention in post-thrombectomy stroke patients in the ICU is associated with poorer functional and neurological outcomes. Consequently, fluid retention emerges as an additional potential predictor for post-intervention stroke outcomes. Our findings provide an initial indication that preventing excessive fluid retention in stroke patients after endovascular thrombectomy could be beneficial for both functional and neurological recovery. Therefore, fluid retention might be an element to consider in optimizing fluid management for stroke patients.

Measuring Hemoglobin A1C with Frozen Packed Cell and Frozen Whole Blood Samples in an Epidemiologic Study: The Reasons for Geographic and Racial Differences in Stroke Study

INTRODUCTION

Hemoglobin A1c (HbA1c) measurement in epidemiology studies could be increased if reliability of measurements in frozen stored samples was known. In the Reasons for Geographic And Racial Differences in Stroke, a longitudinal study of 30,239 Black and White U.S. adults, we investigated reliability of HbA1c measurements for two types of samples stored at -80°C for up to 14 years.

METHODS

Among 917 participants without diabetes, HbA1c was measured in 2017 in frozen packed cells from the first visit (2003-2007) and in frozen whole blood samples from the second visit (2013-2016). To study reliability, associations between HbA1c and glycemia-related characteristics were examined.

RESULTS

Each 10 mg/dL greater fasting glucose was associated with 0.08% (95% CI: 0.05%-0.11%) greater HbA1c in frozen packed cells (Visit 1) and 0.10% (95% CI: 0.08%-0.12%) greater HbA1c in whole blood (Visit 2). HbA1c was also similarly higher with both methods with increasing age, gender, systolic blood pressure, body mass index, high-density lipoprotein, triglycerides, C-reactive protein, and hemoglobin. Using both methods, ≤ 3.5% would be classified with diabetes based on HbA1c ≥ 6.5%.

CONCLUSIONS

In REGARDS participants without diabetes, HbA1c measurement appeared reliable in frozen packed cells or whole blood under long-term storage, suggesting acceptability for study of the epidemiology of HbA1c.

Kidney Function, Cognitive Impairment, and Trajectories: A Longitudinal Biracial Study

BACKGROUND

Chronic kidney disease (CKD) is associated with incident cognitive impairment (ICI) and disproportionately affects older adults and Black persons.

OBJECTIVE

To determine (1) whether age or race differences exist in the association of CKD and ICI and (2) whether cognitive trajectories differ in people with and without CKD.

DESIGN

Nationwide cohort study.

PARTICIPANTS

A total of 22,435 Black and White adults age ≥ 45 years without baseline cognitive impairment.

MEASUREMENTS

Creatinine-cystatin C-based eGFR and albumin-to-creatinine ratio (ACR). Six-item screener (SIS) of global cognition every 6 months, three cognitive domain tests (memory, semantic, and letter fluencies) every 2 years for 10 years. Logistic regression for risk of CI and latent growth curve models for trajectory analysis.

RESULTS

Participants were 56% female, 37% Black, 56% hypertensive, and 19% had diabetes. Overall, 13% (n = 2959) developed ICI over 10 years. In mid-life (age 45- < 65), the OR (95% CI) of ICI for eGFR < 45 vs eGFR ≥ 90 was 1.9 (1.2, 3.0); in late-life (≥ 65), the OR was 0.9 (0.7, 1.1), p interaction < 0.001. For ACR > 300 vs ACR < 10, in mid-life and late-life, the ORs were 1.6 (1.0, 2.6) and 1.0 (0.7, 1.4), p interaction 0.02. Compared to those with eGFR ≥ 60, eGFR < 60 was associated with lower initial cognitive domains scores, worse in mid-life than late-life, but the slopes did not differ. Compared to ACR < 30, ACR ≥ 30 had lower initial cognitive domain scores, which were similar in mid and late-life, and a steeper decline for memory scores. No differences by race were observed.

CONCLUSIONS

Kidney disease was more strongly linked to cognitive impairment in mid-life than in late-life. Albuminuria was associated with steeper decline in memory function, especially in mid-life.

PRIMARY FUNDING SOURCE

NIGMS.

Irisin Alleviates Cognitive Impairment by Inhibiting AhR/NF-κB-NLRP3-Mediated Pyroptosis of Hippocampal Neurons in Chronic Kidney Disease

Introduction: Cognitive impairment is a vital complication of chronic kidney disease (CKD). The effect of irisin on CKD-induced cognitive impairment remains unclear. In the present study, we aimed to investigate the role of Irisin in mitigating cognitive impairment and explore the underlying mechanisms in CKD. Methods: A CKD mice model was established by adenine. Cognitive function was assessed via the novel object recognition (NOR). Interleukin-1β (IL-1β) levels were measured by enzyme-linked immunosorbent assay (ELISA), while pyroptosis-related protein expression was analyzed using western blotting. Results: Our data showed an upregulation of cell pyroptosis in hippocampus tissues of CKD mice, accompanied by significant cognitive impairment. Pyroptosis and cognitive impairment was both improved by Irisin treatment in vivo. Additionally, irisin markedly downregulated pyroptosis levels through aryl hydrocarbon receptor (AhR)/NF-κB p65 signaling in HT-22 cells pretreated with indoxyl sulfate (IS). In vitro experiments further confirmed that pyroptosis was inhibited by AhR and NF-κB p65 inhibitors. Conclusions: We first demonstrated that irisin alleviated cognitive impairment by inhibiting AhR/NF-κB-NLRP3-mediated pyroptosis of hippocampal neurons in CKD. Overall, irisin may have the potential to serve as a critical antipyroptotic agent for improving CKD-induced cognitive impairment.

Plasma Biomarkers of Kidney Health and Mortality in Diabetes and Chronic Kidney Disease in the REGARDS Study

Key Points

In diabetes and CKD, creatinine- and cystatin C–based eGFR has a strong inverse correlation with plasma TNF receptor 1, TNF receptor 2, and soluble urokinase-type plasminogen activator receptor. Higher plasma soluble TNF receptors 1 and 2 and soluble urokinase-type plasminogen activator receptor were each individually associated with mortality, independent of baseline kidney measures.

Background

Several plasma biomarkers of kidney health have been associated with CKD progression in persons with diabetes, but their associations with mortality risk have been largely unexplored.

Methods

In a random sample of 594 participants with diabetes and creatinine-based eGFR <60 ml/min per 1.73 m2 from the REGARDS cohort study, Cox proportional hazards regression was used to determine hazard ratios of mortality by plasma concentrations of soluble TNF receptors 1 and 2 (TNFR1 and TNFR2), soluble urokinase-type plasminogen activator receptor (suPAR), kidney injury molecule 1 (KIM-1), chitinase 3–like 1 (YKL-40), and monocyte chemotactic protein 1 (MCP-1). Covariates included sociodemographic and clinical factors, urine albumin-to-creatinine ratio (UACR), and creatinine- and cystatin C–based eGFR (eGFRcr-cys).

Results

At baseline, the mean age was 70 years, 47% were male, 53% self-identified as Black, mean±SD eGFRcr-cys was 41±13 ml/min per 1.73 m2, and median (interquartile range) UACR was 32 (9–224) mg/g. Correlations with eGFRcr-cys were stronger for TNFR1, TNFR2, and suPAR (r =−0.72 to −0.76) than for KIM-1, YKL-40, and MCP-1 (r =−0.10 to −0.40). With a median follow-up of 7 years, 332 participants died. In models adjusted for sociodemographic and clinical factors, each SD higher baseline concentration of plasma TNFR1 (hazard ratio [HR], 1.28; 95% confidence interval [CI], 1.20 to 1.38), TNFR2 (HR, 1.61; 95% CI, 1.42 to 1.82), suPAR (HR, 1.33; 95% CI, 1.22 to 1.44), KIM-1 (HR, 1.20; 95% CI, 1.08 to 1.33), and YKL-40 (HR, 1.23; 95% CI, 1.11 to 1.38) was associated with higher risk of all-cause mortality, whereas MCP-1 was not. Upon further adjustment for baseline eGFRcr-cys and UACR, only the associations for TNFR1 (HR, 1.16; 95% CI, 1.04 to 1.29), TNFR2 (HR, 1.34; 95% CI, 1.12 to 1.60), and suPAR (HR, 1.23; 95% CI, 1.11 to 1.36) persisted.

Conclusions

Among adults with diabetes and CKD, higher plasma TNFR1, TNFR2, and suPAR were associated with all-cause mortality, independent of baseline kidney function.

Current Status of the Cognitive Impairment in Chronic Kidney Disease

Chronic kidney disease (CKD) is a recognized risk factor for cognitive impairment and dementia. Unfortunately, the number of patients with both CKD and dementia has been steadily increasing with the aging patient population. Therapeutic management and clinical decision-making become more challenging in patients with dementia who often experience worsening prognoses, highlighting the urgency of developing effective countermeasures. This review explores available research on the epidemiology, contributing factors, mechanisms, and outcomes of cognitive impairment and dementia in patients with CKD while outlining the impact of exercise therapy on cognitive function.

Analysis of Levels of Vitamin D, Beta-Amyloid 42, Indoxyl Sulfate, and Serum Parathyroid Hormone in Hemodialysis Patients with Cognitive Impairment

Objective

Cognitive impairment is a recurrent complication in people with chronic kidney disease (CKD), which includes those undergoing hemodialysis (HD). Researchers aimed to analyze vitamin D levels, beta-amyloid 42, indoxyl sulfate, and serum parathyroid hormone (PTH) in patients with cognitive impairment who underwent HD.

Design

This comparative, cross-sectional study was conducted at the HD unit of Dr. M Djamil Padang Hospital. This study enrolled 60 patients with CKD who underwent routine HD and 20 normal subjects as controls. In both groups, serum levels of vitamin D, beta-amyloid 42, indoxyl sulfate, and PTH were measured using the enzyme-linked immunosorbent assay method, and cognitive function was assessed using the Indonesian version of the Montreal Cognitive Assessment neuropsychological test.

Results

The mean±standard deviation age of the study subjects was 51.48±11.44 years, with 53.4 percent being male. Vitamin D levels were higher in the control group, compared to the case group (p<0.05). The case group had higher levels of beta-amyloid, indoxyl sulfate, and PTH, compared to the control group (p<0.05). Significant differences were found in vitamin D and indoxyl sulfate levels between the groups with and without cognitive impairment (p<0.05).

Conclusion

Lower levels of vitamin D and higher levels of indoxyl sulfate were observed in the group with cognitive impairment when compared to the group without cognitive impairment.

Risk factors for cognitive dysfunction amongst patients with cardiovascular diseases

Background

The impact of cardiovascular diseases on cognition raises important research questions. The study aimed to investigate the relationship between demographic data, cardiovascular diseases, kidney disease and depressive symptoms on cognition.

Methods

A cross-sectional study of patients with cardiovascular diseases was performed. The Montreal Cognitive Assessment (MoCA) was applied for cognitive evaluation. Based on MoCA three groups were defined: preserved cognition, mild, and advanced cognitive dysfunction (CD). Data were analyzed using Cronbach alpha (Cα) and McDonald's ω (Mω) for internal consistency. The Chi-square test, Cramer's V test, and correlation analyses were also applied.

Results

Of 628 patients, 55.2% had mild CD, and the mean age was 67.95 (SD 9.53) years. Cα and Mω were 0.7, indicating good internal consistency. We found a moderate positive correlation between depression and the severity of CD (r = 0.25, p = 0.0001). A weak association between CD and female gender (p = 0.016), atrial fibrillation (p = 0.03), stroke (p = 0.009), and a moderate association for age group (p < 0.0001), education level (p < 0.0001), smoking (p < 0.0001), and renal dysfunction (p < 0.0001) was found. Age ≥ 70 years, eGFR 30-59 mL/min/1.73m2 significantly increased the likelihood for mild and advanced CD, while smoking and > 9 classes decreased it. Female gender, history of atrial fibrillation, and stroke significantly increased the likelihood of advanced CD.

Conclusion

Mild CD was the most common in patients with cardiovascular diseases. Older age, lower education, being a non-smoker, and renal dysfunction were risk factors for both mild and advanced CD. Female gender, previous diagnosis of atrial fibrillation, and stroke are risk factors for advanced CD.

Trajectory of Cognitive Decline After Incident Heart Failure Hospitalization: Findings From the REGARDS Study

BACKGROUND

Cognitive impairment is common among adults with heart failure (HF) and associated with poor outcomes. However, less is known about the trajectory of cognitive decline after a first HF hospitalization. We examined the rate of cognitive decline among adults with incident HF hospitalization compared with those without HF hospitalization.

METHODS AND RESULTS

The REGARDS (Reasons for Geographic and Racial Differences in Stroke) study is a prospective longitudinal study of 23 894 participants aged ≥45 years free of HF at baseline. HF hospitalization was expert adjudicated. Changes in global cognitive function (primary outcome) were assessed with the Six-Item Screener (range, 0-6). Secondary outcomes included change in Word List Learning (range, 0-30), Word List Delayed Recall (WLD; range, 0-10), and Animal Fluency Test (range, 0+). Segmented linear mixed-effects regression models were used. Over 5 years, mean scores across all 4 cognitive tests declined for all participants regardless of HF status. Those with incident HF hospitalization experienced faster declines in the Six-Item Screener versus those who were HF free (difference, -0.031 [95% CI, -0.047 to -0.016]; P<0.001), a finding that persisted in fully adjusted models. Those with incident HF hospitalization did not experience faster declines in Word List Learning, Word List Delayed Recall, or Animal Fluency Test scores compared with those without HF hospitalization. Participants with hospitalization for HF with preserved, compared with reduced, ejection fraction had faster decline in Animal Fluency Test.

CONCLUSIONS

Global cognitive decline occurred faster among adults with incident HF hospitalization compared with those who remained free of HF hospitalization. This pattern was not seen for the other cognitive domains.

Association Between Cognitive Function and Risk of Chronic Kidney Disease: A Longitudinal Cohort and Mendelian Randomization Study

OBJECTIVE

To investigate the causal dose-response association between cognitive function and the risk of chronic kidney disease (CKD) by a longitudinal cohort and mendelian randomization study.

METHODS

The longitudinal cohort study included 396,600 participants without prior dementia and CKD from the UK Biobank. Cognitive function (including prospective memory, numeric memory, visuospatial memory, reaction time, and reasoning ability) was assessed by computerized touchscreen tests. Global cognitive function was defined as a composite score of those specific cognitive domains. A 2-stage mendelian randomization analysis was conducted with 12,979 cases of CKD and 379,424 controls. Genetically predicted global cognitive function was instrumented with 91 confirmed genome-wide significant variants. The study outcome was new-onset CKD. The study was conducted from March 13, 2006, to September 30, 2021.

RESULTS

During a median follow-up of 12.5 years, new-onset CKD developed in 13,090 participants. Per 1 SD score increments in reaction time (adjusted hazard ratio [HR], 0.97; 95% CI, 0.95 to 0.99), reasoning ability (adjusted HR, 0.91; 95% CI, 0.88 to 0.94), and global cognitive function (adjusted HR, 0.96; 95% CI, 0.95 to 0.98) were associated with a significantly lower risk of new-onset CKD. Compared with an incorrect answer in the prospective memory test, a correct answer was associated with a lower risk of new-onset CKD (adjusted HR, 0.82; 95% CI, 0.76 to 0.88). Mendelian randomization analyses found that per 1 SD score increments in genetically predicted global cognitive function resulted in a significantly (7%; 95% CI, 2% to 12%) lower risk of new-onset CKD.

CONCLUSION

A better cognitive function is causally associated with a lower risk of CKD in participants without prior dementia.

The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) Diet and Metabolites in Chronic Kidney Disease

The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) is a hybrid of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets, and its association with renal outcomes remains unclear. In the REasons for Geographic and Racial Disparities in Stroke (REGARDS) cohort, diet data were collected at baseline using food frequency questionnaires. Modified Poisson regression was used to examine the association of MIND diet with incident chronic kidney disease (CKD). In the REGARDS stroke case-cohort, 357 metabolites were measured in baseline plasma. Weighted linear regression was used to test associations between MIND diet and metabolites. Weighted logistic regression was used to test associations between MIND-associated metabolites and incident CKD. Mediation analyses were conducted to determine whether metabolites mediated the relationship between MIND diet and CKD. A higher MIND diet score was associated with a decreased risk of incident CKD (risk ratio 0.90, 95% CI (0.86-0.94); p = 2.03 × 10-7). Fifty-seven metabolites were associated with MIND diet (p < 3 × 10-4). Guanosine was found to mediate the relationship between MIND diet and incident CKD (odds ratio for indirect effects 0.93, 95% CI (0.88-0.97); p < 0.05). These findings suggest a role of the MIND diet in renal outcomes.

Endothelial Dysfunction Biomarkers and CKD Incidence in the REGARDS Cohort

Introduction

Chronic kidney disease (CKD) is only partly caused by traditional risk factors. Endothelial dysfunction is common in CKD and may contribute to CKD incidence. We studied the association of circulating biomarkers reflecting endothelial dysfunction with incident CKD.

Methods

The Reasons for Geographical and Racial Differences in Stroke (REGARDS) study is a prospective cohort of 30,239 Black or White adults aged ≥45 years. Baseline levels of intercellular cellular adhesion molecule 1 (ICAM-1), vascular cellular adhesion molecule 1 (VCAM-1), factor VIII (FVIII), and E-selectin were measured in 3300 participants without baseline CKD or albuminuria who attended a second visit 9.4 years later. Kidney outcomes were incident CKD (estimated glomerular filtration rate [eGFR] <60 ml/min per 1.73 m2 and ≥40% decline or onset of new end-stage kidney disease), incident ≥30% eGFR decline, and incident albuminuria (albumin-to-creatinine ratio [ACR] ≥30 mg/g). Sequentially adjusted logistic regression models assessed the association of biomarkers with kidney outcomes.

Results

Median age of participants was 62 years, 49% were women, and 46% identified as Black. Of the participants, 228 (6.9%) developed CKD, 613 (18.9%) experienced ≥30% decline in eGFR, and 356 (11.4%) developed albuminuria. The adjusted odds ratios (ORs) for incident CKD per 1 SD increment biomarker was 1.12 for ICAM-1 (95% confidence interval [CI]: 1.02-1.22), 1.10 for VCAM-1 (95% CI: 1.01-1.20), 1.15 for FVIII (95% CI: 1.06-1.24), and 1.10 for E-selectin (95% CI: 1.01-1.20). Results were similar for incident ≥30% eGFR decline but not albuminuria, where only higher FVIII was positively associated.

Conclusion

Higher concentration of ICAM-1, VCAM-1, FVIII, and E-selectin were associated with incident CKD and ≥30% eGFR decline in a large cohort study. Higher FVIII was also associated with incident albuminuria.

Changes in Cognitive Function After Kidney Transplantation: A Longitudinal Cohort Study

RATIONALE & OBJECTIVE

Kidney disease negatively affects cognition. We assessed the effect of kidney transplantation (KT) on different cognitive domains.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

We examined pre- versus post-KT cognition in patients waitlisted for KT at an academic center.

PREDICTORS

Transplant status. We measured cognitive function before KT (n=101), 3 months after KT (n=78), and 1 year after KT (n = 83).

OUTCOMES

Our primary outcome was change in cognitive function before versus after KT. We used standard neuropsychological tests to assess global cognition (Mini-Mental State Exam [MMSE]), episodic/declarative memory (Logical Memory), psychomotor speed/visuospatial function (Digit Symbol Substitution Test [DSST], Trail Making Test [TMT] A), working memory/attention (Digit Span), executive function (TMT B), and semantic memory/verbal fluency/language (Category Fluency).

ANALYTICAL APPROACH

Using linear mixed model analysis, we evaluated the changes in neuropsychological test scores adjusted for age, sex, race, education, and number of assessments.

RESULTS

Before KT, Logical Memory I and II, DSST, MMSE, Category Fluency (animal naming), and Digit Span backward scores were low compared with normative values from the National Alzheimer's Coordinating Center data. Logical Memory I and II scores improved after KT (pre- vs post-KT, estimated group difference [d]=3.3, P<0.001 for Logical Memory I; d=4.27, P<0.001 for Logical Memory II), such that post-KT scores were similar to normative values (post-KT vs normative values, d = -0.37, P=0.06 for Logical Memory I; d = -0.89, P=0.08 for Logical Memory II). Category Fluency (animal naming; d=2.4, P<0.001) and DSST (d=3.12, P=0.01) scores also improved with KT, but post-KT DSST scores remained lower than normative values (post-KT vs normative values, d = -5.17, P<0.001). MMSE, Digit Span, and TMT A and B scores did not change after KT.

LIMITATIONS

Single-center study.

CONCLUSIONS

Episodic and verbal declarative memory normalize after KT. Semantic memory, verbal fluency, language, psychomotor speed, and visuospatial function show partial improvement. Cognitive impairment in kidney disease is therefore at least partly reversible with KT.

PLAIN-LANGUAGE SUMMARY

Cognitive impairment in kidney disease affects self-esteem, vocational abilities, quality of life, health care costs, and mortality. It is not clear whether kidney transplantation (KT) improves cognition and whether the improvement is uniform across cognitive domains. The distinction between reversible and irreversible cognitive impairment has important implications in the clinical care of patients before and after KT. We assessed cognition before KT and 3 months and 12 months after KT and discovered that episodic and verbal declarative memory normalized with KT. Semantic memory, verbal fluency, language, psychomotor speed, and visuospatial function also improved with KT but did not reach normal levels. Cognitive impairment in kidney disease is therefore at least partly reversible.

Prevalence of cognitive impairment and its predictors among chronic kidney disease patients: A systematic review and meta-analysis

BACKGROUND

Cognitive impairment (CI) is common among patients with chronic kidney disease (CKD), and is associated with a poor prognosis. We assessed the prevalence and associated factors of CI in patients with CKD.

METHODS

A systematic review and meta-analysis were conducted by searching PubMed, Embase, and the Web of Science through December 1, 2023. Random effects models were performed with subgroup analyses to further explore the heterogeneity.

RESULTS

50 studies involving 25,289 CKD patients were included. The overall prevalence of CI was 40% (95% confidence interval 33-46). The pooled prevalence of CI was relatively higher in CKD patients from Africa (58%), Asia (44%) and America (37%). Attention and executive dysfunction appeared to be the most common manifestations. The prevalence of CI was higher among patients with hemodialysis (53%) and peritoneal dialysis (39%) than those without dialysis (32%) and post-kidney transplanted (26%). In addition, advanced age, the presence of diabetes and hypertension might increase the risk of CI in CKD patients.

CONCLUSIONS

People with CKD have a high prevalence of CI, especially in patients with hemodialysis. An early and comprehensive screening for CI in CKD patients is needed to improve clinical outcomes.

TRIAL REGISTRATION

Registration number: PROSPERO (CRD42023412864).

Mid- and Late-Life Chronic Kidney Disease Is Associated with Parkinson's Disease, Not with an Increased Risk of Alzheimer's Disease

Chronic kidney disease (CKD) is strongly associated with dementia. However, its independent association with Alzheimer's or Parkinson's disease remains unclear. This study investigated the prospective association of patients with CKD aged ≥55 years with an increased risk of Alzheimer's or Parkinson's disease. We conducted a retrospective cohort analysis using a national cohort sample of approximately one million patients. Primary outcome indicators measured included incidence of all-cause dementia, Alzheimer's disease, and Parkinson's disease events using person-years at risk. The hazard ratio was adjusted using the Cox proportional hazards model. We included 952 patients without CKD and 476 with CKD over 55 years using propensity score matching. The CKD group exhibited higher incidences of all-cause dementia, Parkinson's disease, and Alzheimer's disease than the non-CKD group. Furthermore, the CKD group had an elevated risk of all-cause dementia and a significantly increased risk of Parkinson's disease, especially among older women. Notably, the risk of Parkinson's disease was higher within the first 3 years of CKD diagnosis. These findings emphasize the link between CKD in mid- and late-life individuals and a higher incidence of all-cause dementia and Parkinson's disease rather than Alzheimer's disease.

Predictors of cognitive impairment and its association with mortality in maintenance hemodialysis patients: A prospective follow-up study

Objective

To determine predictors of cognitive impairment (CI) and its association with mortality in maintenance haemodialysis (MHD) patients.

Methods

This prospective follow up study was conducted at HD Department, Mayo Hospital, Lahore from September, 2021 to November, 2022. All patients undergoing MHD for more than three months and having age between 18-65 years were included while those with dialysis duration less than three months, history of neuropsychiatric illness was excluded. Cognitive function was assessed using British Columbia Cognitive Complaints Inventory (BC-CCI) questionnaire. CI was defined on Likert scale as mild, moderate, and severe. Patients were followed up to one year regarding outcome measures.

Results

One hundred and four patients were included in the study. Mean age was 45.86±11.11 years and Diabetes Mellitus (DM) was the most common cause of End Stage Renal Disease (ESRD) in 39(37.5%) patients. CI was found in 86(82.7%) patients in following order of severity: mild 61(58.7%), moderate 19(18.3%) and severe 6(5.9%). Increasing age (≥50 years), gender (female), Diabetes Mellitus (DM), unemployment and education <10th grade were found as significant predictors of CI (p<0.05). Significant positive correlations of CI score with age (r=0.338, p<0.001) and MHD duration (r=0.211, p=0.032) were found. However, the CI was not significantly associated with mortality (p=0.302).

Conclusion

CI was common in MHD patients. Factors affecting CI were increasing age, female gender, DM, unemployment and low education level. CI was not associated with mortality in MHD patients.

Efficacy of erythropoietin as a neuroprotective agent in CKD-associated cognitive dysfunction: A literature systematic review

Patients with chronic kidney disease (CKD) often experience mild cognitive impairment and other neurocognitive disorders. Studies have shown that erythropoietin (EPO) and its receptor have neuroprotective effects in cell and animal models of nervous system disorders. Recombinant human EPO (rHuEPO), commonly used to treat anemia in CKD patients, could be a neuroprotective agent. In this systematic review, we aimed to assess the published studies investigating the cognitive benefits of rHuEPO treatment in individuals with reduced kidney function. We comprehensively searched Pubmed, Cochrane Library, Scopus, and Web of Science databases from 1990 to 2023. After selection, 24 studies were analyzed, considering study design, sample size, participant characteristics, intervention, and main findings. The collective results of these studies in CKD patients indicated that rHuEPO enhances brain function, improves performance on neuropsychological tests, and positively affects electroencephalography measurements. These findings suggest that rHuEPO could be a promising neuroprotective agent for managing CKD-related cognitive impairment.

Cognitive decline related to chronic kidney disease as an exclusion factor from kidney transplantation: results from an international survey

Background and hypothesis

There seems to be a lack of consensus on the necessity and the modality of psychological and specifically cognitive assessment of candidates for kidney transplantation. Both points are often delegated to individual hospitals/centres, whereas international guidelines are inconsistent. We think it is essential to investigate professionals' opinions to advance towards a consistent clinical practice.

Methods

This paper presents the results of an international survey among clinical professionals, mainly nephrologists from the CONNECT (Cognitive decline in Nephro-Neurology: European Cooperative Target) network and beyond (i.e. from personal contacts of CONNECT members). The survey investigated their opinions about the question of whether cognitive decline in patients with chronic kidney disease may affect their eligibility for kidney transplantation.

Results

Our results show that most clinicians working with patients affected by chronic kidney disease think that cognitive decline may challenge their eligibility for transplantation despite data that suggest that, in some patients, cognitive problems improve after kidney transplantation.

Conclusion

We conclude that three needs emerge as particularly pressing: defining agreed-on standards for a multifaceted and multifactorial assessment (i.e. including both clinical/medical and psychosocial factors) of candidates with chronic kidney disease to kidney transplantation; further investigating empirically the causal connection between chronic kidney disease and cognition; and further investigating empirically the possible partial reversibility of cognitive decline after kidney transplantation.

Chronic kidney disease and cognitive performance: NHANES 2011-2014

PURPOSE

Previous studies suggest an association between chronic kidney disease (CKD) and cognitive impairment. The purpose of this study was to explore the association between the diverse stages of CKD and the cognitive performance of elderly American adults.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 were used. Multivariate adjusted logistic regression, subgroup analysis, and the restricted cubic spline model were used to assess the associations of CKD stage and estimated glomerular filtration rate (eGFR) with cognitive performance. The measures used to evaluate cognitive function included the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) test, the Animal Fluency test, and the Digit Symbol Substitution test (DSST).

RESULTS

This study included 2234 participants aged ≥ 60 years. According to the fully adjusted model, stages 3-5 CKD were significantly associated with the CERAD test score (OR = 0.70, 95% CI [0.51, 0.97], p = 0.033), the Animal Fluency test score (OR = 0.64, 95% CI [0.48, 0.85], p = 0.005), and the DSST score (OR = 0.60, 95% CI [0.41, 0.88], p = 0.013). In addition, the incidence of poor cognitive function increased with decreasing eGFR, especially for individuals with low and moderate eGFRs. Both the DSST score (p nonlinearity < 0.0001) and the Animal Fluency test score (p nonlinearity = 0.0001) had nonlinear dose-response relationships with the eGFR. However, a linear relationship was shown between the eGFR and CERAD test score (p nonlinearity = 0.073).

CONCLUSIONS

CKD, especially stages3-5 CKD, was significantly associated with poor cognitive performance in terms of executive function, learning, processing speed, concentration, and working memory ability. All adults with CKD should be screened for cognitive impairment.

Modification of Association of Cystatin C With Kidney and Cardiovascular Outcomes by Obesity

RATIONALE & OBJECTIVE

Cystatin C-based estimated glomerular filtration rate (eGFRcys) has stronger associations with adverse clinical outcomes than creatinine-based eGFR (eGFRcr). Obesity may be associated with higher cystatin C levels, independent of kidney function, but it is unknown whether obesity modifies associations of eGFRcys with kidney and cardiovascular outcomes.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

27,249 US adults in the Reasons for Geographic and Racial Differences in Stroke Study.

PREDICTORS

eGFRcys, eGFRcr, waist circumference, and body mass index (BMI).

OUTCOME

All-cause mortality, kidney failure, incident atherosclerotic cardiovascular disease (ASCVD), and incident heart failure (HF).

ANALYTICAL APPROACH

Multivariable Cox and Fine-Gray models with multiplicative interaction terms were constructed to investigate whether waist circumference quartiles or BMI categories modified associations of eGFRcys with risks of 4 clinical outcomes.

RESULTS

Participants had a mean age of 65 years; 54% were women, 41% were Black, and 21% had an eGFRcys<60mL/min/1.73m2. The baseline prevalence of abdominal obesity (waist circumference≥88cm for women or≥102cm for men) was 48% and obesity was 38%. In multivariable adjusted analyses, each 15mL/min/1.73m2 lower eGFRcys was associated with higher HR and 95% CI of mortality in each waist circumference quartile (first quartile, 1.19 [1.15-1.24]; second quartile, 1.22 [1.18-1.26]; third quartile, 1.20 [1.16-1.24]; fourth quartile, 1.19 [1.15-1.23]) as well as within each BMI category (BMI<24.9: 1.21 [1.17-1.25]; BMI 25.0-29.9: 1.21 [1.18-1.25]; BMI 30.0-34.9: 1.20 [1.16-1.25]; BMI≥35: 1.17, [1.12-1.22]). Neither waist circumference nor BMI modified the association of eGFRcys with mortality, kidney failure, incident ASCVD, or incident HF (all Pinteraction>0.05).

LIMITATIONS

Included only Black and White persons in the United States.

CONCLUSION

Obesity did not modify the association of eGFRcys with all-cause mortality, kidney failure, incident ASCVD, or incident HF. Among individuals with obesity, cystatin C may be used to provide eGFR-based risk prognostication for adverse outcomes.

PLAIN-LANGUAGE SUMMARY

Cystatin C is increasingly used in clinical practice to estimate kidney function, and cystatin C-based eGFR (eGFRcys) may be used to determine risk for adverse clinical outcomes. Adiposity may increase serum levels of cystatin C, independent of kidney function. This cohort study investigated whether associations of eGFRcys with adverse kidney and cardiovascular outcomes are modified by measures of obesity, waist circumference, and body mass index. We found that obesity does not modify associations of eGFRcys with 4 clinical outcomes and conclude that among individuals with obesity, cystatin C may be used to provide eGFR-based risk prognostication for adverse outcomes.

More rapid progression of brain atrophy in patients on peritoneal dialysis compared with hemodialysis: The VCOHP Study

We previously reported that brain atrophy was more severe and progressed more rapidly in patients with end-stage kidney disease on peritoneal dialysis (PD) than those with non-dialysis-dependent chronic kidney disease. However, it remains unknown whether there is a difference between patients on PD and hemodialysis (HD). In total, 73 PD and 34 HD patients who underwent brain magnetic resonance imaging (MRI) were recruited for a cross-sectional analysis. Among them, 42 PD and 25 HD patients who underwent a second brain MRI after 2 years were recruited for a longitudinal analysis. T1-weighted MRI images were analyzed. Total gray matter volume (GMV), total white matter volume, and cerebrospinal fluid volume were segmented, and each volume was quantified using statistical parametric mapping software. The ratio of GMV (GMR) was calculated by dividing GMV by intracranial volume, to adjust for variations in head size. We compared GMR between PD and HD patients in the cross-sectional analysis and the annual change in GMR (AC-GMR) in the longitudinal analysis. In the cross-sectional analysis, age- and sex-adjusted GMR was significantly lower in PD than HD patients [least square mean (LSM): 39.2% vs. 40.0%, P = 0.018]. AC-GMR was significantly greater in PD than HD patients and this difference remained significant even after adjustment for potential confounding factors (LSM: -0.68 vs. -0.28 percentage-points/year, P = 0.011). In conclusion, the present study demonstrated a more rapid progression of brain atrophy in PD patients compared with HD patients. We demonstrated that decline in GMR progressed significantly more rapidly in PD than HD patients independent of potential confounding factors. GMR gray matter volume ratio, HD hemodialysis, PD peritoneal dialysis.

Cognitive Impairment and Brain Atrophy in Patients with Chronic Kidney Disease

In Japan, the aging of the population is rapidly accelerating, with an increase in patients with chronic kidney disease (CKD) and those undergoing dialysis. As a result, the number of individuals with cognitive impairment (CI) is rising, and addressing this issue has become an urgent problem. A notable feature of dementia in CKD patients is the high frequency of vascular dementia, making its prevention through the management of classical risk factors such as hypertension, diabetes mellitus, dyslipidemia, smoking, etc., associated with atherosclerosis and arteriosclerosis. Other effective measures, including the use of renin-angiotensin system inhibitors, addressing anemia, exercise therapy, and lifestyle improvements, have been reported. The incidence and progression of CI may also be influenced by the type of kidney replacement therapy, with reports suggesting that long-duration dialysis, low-temperature hemodialysis, peritoneal dialysis, and kidney transplantation can have a preferable effect on the preservation of cognitive function. In conclusion, patients with CKD are at a higher risk of developing CI, with brain atrophy being a contributing factor. Despite the identification of various preventive measures, the evidence substantiating their efficacy remains limited across all studies. Future expectations lie in large-scale randomized controlled trials.

Association between kidney measurements and cognitive performance in patients with ischemic stroke

BACKGROUND

Individuals with chronic kidney disease (CKD) are at a substantially higher risk for stroke, which may predispose individuals to cognitive impairment. However, the association of low estimated glomerular filtration rate (eGFR) and albuminuria with poorer cognitive performance in patients with stroke is not fully understood, and the current evidence for this association is contradictory. Our aim was to retrospectively investigate whether low eGFR and albuminuria, as indicated by the urine albumin-creatinine ratio (UACR), are independently or jointly associated with worse cognitive performance in patients with ischemic stroke.

METHODS

This retrospective study included 608 patients with acute ischemic stroke. Their UACR and eGFR values were obtained from inpatient medical records. Global cognitive function was assessed with the mini-mental state exam (MMSE) and Montreal Cognitive Assessment (MoCA) one month after hospital discharge. The relationship between renal measures and cognitive performance was assessed using univariate and multiple linear regression analyses. Potential confounders included age, gender, BMI, education, diabetes and hypertension history, NIHSS score, smoking and alcohol consumption status, serum total cholesterol, triglyceride, fasting glucose, uric acid, homocysteine, systolic blood pressure, and either eGFR or UACR.

RESULTS

Patients had an average age of 66.6±4.1 years, and 48% were females. Average eGFR and UACR were 88.4±12.9 ml/min/1.73m2 and 83.6±314.2 mg/g, respectively. The number of patients with eGFR ≥90, 60-89, and <60 ml/min/1.73 m2 was 371 (61%), 207 (34%), and 30 (5%), respectively, and the percentage of patients with UACR <30 mg/g, 30-300 mg/g, and >300 mg/g was 56%, 39%, and 5%, respectively. Multivariate adjusted models showed that eGFR was independently associated with MMSE (β = -0.4; 95% CI = -0.5,-0.4; p <0.001) and MoCA (β = -0.6; 95% CI = -0.7,-0.5; p <0.001). However, UACR was not significantly correlated with MMSE or MoCA.

CONCLUSION

In patients with ischemic stroke, reduced eGFR but not albuminuria was associated with lower cognitive performance. These results show that the eGFR decline could be an effective indicator of cognitive impairment after a stroke. Therefore, regular monitoring and early detection of mild renal dysfunction in patients with acute ischemic stroke might be needed.

Post-Stroke Brain Health Monitoring and Optimization: A Narrative Review

Significant advancements have been made in recent years in the acute treatment and secondary prevention of stroke. However, a large proportion of stroke survivors will go on to have enduring physical, cognitive, and psychological disabilities from suboptimal post-stroke brain health. Impaired brain health following stroke thus warrants increased attention from clinicians and researchers alike. In this narrative review based on an open timeframe search of the PubMed, Scopus, and Web of Science databases, we define post-stroke brain health and appraise the body of research focused on modifiable vascular, lifestyle, and psychosocial factors for optimizing post-stroke brain health. In addition, we make clinical recommendations for the monitoring and management of post-stroke brain health at major post-stroke transition points centered on four key intertwined domains: cognition, psychosocial health, physical functioning, and global vascular health. Finally, we discuss potential future work in the field of post-stroke brain health, including the use of remote monitoring and interventions, neuromodulation, multi-morbidity interventions, enriched environments, and the need to address inequities in post-stroke brain health. As post-stroke brain health is a relatively new, rapidly evolving, and broad clinical and research field, this narrative review aims to identify and summarize the evidence base to help clinicians and researchers tailor their own approach to integrating post-stroke brain health into their practices.

Understanding Cognitive Deficits in People with High Blood Pressure

High blood pressure is associated with an elevated risk of dementia. However, much less is known about how high blood pressure is related to cognitive deficits in domains including episodic memory, semantic verbal fluency, fluid reasoning, and numerical ability. By analyzing data from 337 participants (57.39% female) with a history of clinical high blood pressure diagnosis with a mean age of 48.78 ± 17.06 years and 26,707 healthy controls (58.75% female) with a mean age of 45.30 ± 15.92 years using a predictive normative modeling approach and one-sample t-tests, the current study found that people with high blood pressure have impaired immediate (t(259) = -4.71, p < 0.01, Cohen's d = -0.08, 95% C.I. [-0.11, -0.05]) and delayed word recall (t(259) = -7.21, p < 0.01, Cohen's d = -0.11, 95% C.I. [-0.15, -0.08]) performance. Moreover, people with high blood pressure also exhibited impaired performance in the animal naming task (t(259) = -6.61, p < 0.0001, Cohen's d = -0.11, 95% C.I. [-0.15, -0.08]), and number series (t(259) = -4.76, p < 0.01, Cohen's d = -0.08, 95% C.I. [-0.11, -0.05]) and numeracy tasks (t(259) = -4.16, p < 0.01, Cohen's d = -0.06, 95% C.I. [-0.09, -0.03]) after controlling for demographic characteristics. Clinicians and health professionals should consider including these tasks as part of the neuropsychological assessment for people with high blood pressure, to detect their cognitive deficits. Moreover, they should also come up with ways to improve cognitive performance in people with high blood pressure.

Prediction model for cognitive impairment in maintenance hemodialysis patients

PURPOSE

To explore the risk factors for cognitive impairment in patients undergoing maintenance hemodialysis (MHD) and construct a predictive model for cognitive impairment.

METHODS

A total of 146 patients with end-stage renal disease (ESRD) undergoing MHD were recruited at our hospital between December 2021 and April 2022. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA), and scores of < 26 were considered indicative of cognitive impairment. Risk factors were identified using a multivariate logistic regression model, and a receiver operating characteristic curve was applied to construct the prediction model. Cognitive impairment risk was categorized using a multifactorial prediction model based on the weight of evidence.

RESULTS

46 patients with cognitive impairment were identified, with a prevalence of 31.5% in ESRD patients undergoing MHD. Multivariate logistic regression analyses indicated that the following factors were associated with an increased risk of cognitive impairment in patients undergoing MHD: aged 55.0-64.0 years (OR:6.24; 95%CI:1.81-21.48; P = 0.001), aged 65.0-74.0 years (OR:16.10; 95%CI:4.03-64.37; P < 0.001), aged ≥ 75.0 years (OR:90.22; 95%CI:16.86-482.86; P < 0.001), duration of dialysis ≥ 5 years (OR:3.99; 95%CI:1.58-10.04; P = 0.003), and current smoker (OR:4.61; 95%CI:1.46-14.57; P = 0.009). The predictive value of the constructed model based on the aforementioned factors for cognitive impairment was 84% (95%CI,77-91%). The prevalence of cognitive impairment for patients at low, moderately low, moderately high, and high risk was 0% (95%CI:0-17%), 10% (95%CI:3-22%), 32% (95%CI:16-52%), and 65% (95%CI:50-78%), respectively.

CONCLUSIONS

This study constructed a multifactorial prediction model with a high predictive value for cognitive impairment in patients with ESRD undergoing MHD.

Blood Pressure, Incident Cognitive Impairment, and Severity of CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Hypertension is a known risk factor for dementia and cognitive impairment. There are limited data on the relation of systolic blood pressure (SBP) and diastolic blood pressure (DBP) with incident cognitive impairment in adults with chronic kidney disease. We sought to identify and characterize the relationship among blood pressure, cognitive impairment, and severity of decreased kidney function in adults with chronic kidney disease.

STUDY DESIGN

Longitudinal cohort study.

SETTING & PARTICIPANTS

3,768 participants in the Chronic Renal Insufficiency Cohort (CRIC) Study.

EXPOSURE

Baseline SBP and DBP were examined as exposure variables, using continuous (linear, per 10-mm Hg higher), categorical (SBP<120 [reference], 120 to 140,>140mm Hg; DBP<70 (reference), 70 to 80, > 80mm Hg) and nonlinear terms (splines).

OUTCOME

Incident cognitive impairment defined as a decline in Modified Mini-Mental State Examination (3MS) score to greater than 1 standard deviation below the cohort mean.

ANALYTICAL APPROACH

Cox proportional hazard models adjusted for demographics as well as kidney disease and cardiovascular disease risk factors.

RESULTS

The mean age of participants was 58±11 (SD) years, estimated glomerular filtration rate (eGFR) was 44mL/min/1.73m2 ± 15 (SD), and the median follow-up time was 11 (IQR, 7-13) years. In 3,048 participants without cognitive impairment at baseline and with at least 1 follow-up 3MS test, a higher baseline SBP was significantly associated with incident cognitive impairment only in the eGFR>45mL/min/1.73m2 subgroup (adjusted hazard ratio [AHR], 1.13 [95% CI, 1.05-1.22] per 10mm Hg higher SBP]. Spline analyses, aimed at exploring nonlinearity, showed that the relationship between baseline SBP and incident cognitive impairment was J-shaped and significant only in the eGFR>45mL/min/1.73m2 subgroup (P=0.02). Baseline DBP was not associated with incident cognitive impairment in any analyses.

LIMITATIONS

3MS test as the primary measure of cognitive function.

CONCLUSIONS

Among patients with chronic kidney disease, higher baseline SBP was associated with higher risk of incident cognitive impairment specifically in those individuals with eGFR>45mL/min/1.73m2.

PLAIN-LANGUAGE SUMMARY

High blood pressure is a strong risk factor for dementia and cognitive impairment in studies of adults without kidney disease. High blood pressure and cognitive impairment are common in adults with chronic kidney disease (CKD). The impact of blood pressure on the development of future cognitive impairment in patients with CKD remains unclear. We identified the relationship between blood pressure and cognitive impairment in 3,076 adults with CKD. Baseline blood pressure was measured, after which serial cognitive testing was performed over 11 years. Fourteen percent of participants developed cognitive impairment. We found that a higher baseline systolic blood pressure was associated with an increased risk of cognitive impairment. We found that this association was stronger in adults with mild-to-moderate CKD compared with those with advanced CKD.

Cognitive Impairment in Chronic Kidney Disease Is Associated with Glymphatic System Dysfunction

Introduction

This study was designed to explore the associations between impaired cognition in chronic kidney disease (CKD) patients and the dysfunction of the glymphatic system.

Method

Data were obtained from 77 CKD patients and 50 age-matched healthy control individuals from the First Affiliated Hospital of Zhengzhou University. CKD patients were stratified into with and without impaired cognitive function. T2-weighted magnetic resonance imaging results were used to assess area ratios for the perivascular space and ventricles in participants, while the Montreal Cognitive Assessment and the Mini-Mental State Examination were employed to measure cognitive function. Correlations between the perivascular space or ventricle area ratios and cognitive impairment were assessed in CKD patients.

Results

Significant increases in the burden of enlarged perivascular spaces in the frontal cortex and basal ganglia were observed in CKD patients with cognitive impairment relative to those without such impairment, with a concomitant increase in analyzed ventricle area ratios. Enlarged perivascular spaces in the frontal cortex, basal ganglia and increased area ratios of lateral ventricles and 4th ventricle exhibited relatively high sensitivity and specificity as means of differing between the CKD patients with and without cognitive impairment.

Conclusion

These results indicate that the burden of enlarged perivascular spaces in the frontal cortex and basal ganglia and increases in ventricle area ratio values may offer utility as biomarkers that can aid in detection of even mild cognitive decline in individuals with CKD. The dysfunction of the glymphatic system may play a key role in the pathogenesis of CKD-related cognitive impairment.

Screening of cognitive performance in kidney transplant recipients: a mini review

Why should we screen?

The prevalence of cognitive impairment in kidney transplant recipients (KTRs) is up to 58%. The 10-year graft loss and mortality rates are above 30% and 50%, respectively, and executive malfunctioning increases disadvantageous outcomes.

What causes cognitive impairment in KTRs?

Strong risk factors are older age and chronic kidney disease. However, causes are multifactorial and include cardiovascular, cerebrovascular, neurodegenerative, inflammatory, uremic, psychiatric, and lifestyle-related susceptibilities.

How should we screen?

KTR-specific validated instruments or strategies do not exist. The central element should be a multidomain cognitive screening test that is sensitive to mild cognitive impairment, corrects for age and education, and includes executive functions testing. Cognitive trajectories, effects on everyday life and psychiatric comorbidities should be assessed by integrating the perspectives of both patients and knowledgeable informants.

When should we screen?

Screening should not be postponed if there is suspicion of impaired cognition. Different time points after transplantation tend to have their own characteristics.

Who should conduct the screening?

Screening should not be limited to specialists. It can be carried out by any healthcare professional who has received a limited amount of training.

What are the benefits of screening?

Screening does not provide a diagnosis. However, suggestive results change care in multiple ways. Goals are: Initiation of professional dementia work-up, securing of adherence, anticipation of potential complications (delirium, falls, frailty, functional impairment, malnutrition, etc.), mitigation of behavioral disorders, adjustment of diagnostic and therapeutic "load", reduction of caregiver burden and meeting of changing needs. We summarize data on the prevalence, risk factors and sequelae of cognitive impairment in KTRs. We also discuss the requirements for appropriate screening strategies and provide guiding principles regarding appropriate and safe care.

Methodological challenges and biases in the field of cognitive function among patients with chronic kidney disease

Chronic kidney disease (CKD) affects approximately 850 million people globally and is associated with an increased risk of cognitive impairment. The prevalence of cognitive impairment among CKD patients ranges from 30 to 60%, and the link between CKD and cognitive impairment is partially understood. Methodological challenges and biases in studying cognitive function in CKD patients need to be addressed to improve diagnosis, treatment, and management of cognitive impairment in this population. Here, we review the methodological challenges and study design issues, including observational studies' limitations, internal validity, and different types of bias that can impact the validity of research findings. Understanding the unique challenges and biases associated with studying cognitive function in CKD patients can help to identify potential sources of error and improve the quality of future research, leading to more accurate diagnoses and better treatment plans for CKD patients.

CKD Associates with Cognitive Decline in Middle-Aged and Older Adults with Long-Standing Type 1 Diabetes

Key Points

We found that development of both albuminuria and reduced eGFR was associated with clinically significant cognitive decline, particularly in the psychomotor and mental efficiency domain. There was also a significant interaction between worsened albuminuria and eGFR, the combination of which augmented cognitive deficits. A more comprehensive longitudinal phenotype of albuminuria showed that regressed albuminuria did not associate with worsened cognitive decline, as opposed to persistent albuminuria.

Background

Individuals with CKD or type 1 diabetes (T1D) are at risk for cognitive decline, but it is unclear whether these associations are with albuminuria, eGFR, or both.

Methods

We examined the longitudinal relationships between CKD and change in cognition in 1051 participants with T1D in the Diabetes Control and Complications Trial and its follow-up, the Epidemiology of Diabetes Interventions and Complications study. Albumin excretion rate and eGFR were measured every 1–2 years. Three cognitive domains were assessed repeatedly over a 32-year period: immediate memory, delayed memory, and psychomotor and mental efficiency. Associations between cognitive function and CKD were assessed: (1 ) longitudinally and (2 ) in models using eGFR and albuminuria measurements over the first 15–20 years with subsequent change in cognitive function over the ensuing 14 years (when decline in cognition was greatest).

Results

In fully adjusted longitudinal analyses, the magnitude of decline in the psychomotor and mental efficiency domain score was associated with eGFR <60 ml/min per 1.73 m2 (β −0.449; 95% confidence interval [CI], −0.640 to −0.259) and sustained albumin excretion rate 30 to <300 mg/24 hours (β −0.148; 95% CI, −0.270 to −0.026). This was equivalent to a decrease associated with approximately 11 and 4 years of aging, respectively. In analyses focused on changes in cognition between study years 18 and 32, eGFR <60 ml/min per 1.73 m2 was associated with reduced psychomotor and mental efficiency (β −0.915; 95% CI, −1.613 to −0.217).

Conclusions

In T1D, development of CKD was associated with a subsequent reduction on cognitive tasks requiring psychomotor and mental efficiency. These data highlight the need for increased recognition of risk factors for neurologic sequelae in patients with T1D, as well as preventive and treatment strategies to ameliorate cognitive decline.

Relationships between serum Klotho concentrations and cognitive performance among older chronic kidney disease patients with albuminuria in NHANES 2011-2014

Background

The potential relationship between Klotho and cognitive function is limited and controversial. This study aimed to quantify the association of Klotho and cognitive impairment in chronic kidney disease (CKD) patients with albuminuria.

Methods

Serum Klotho was measured by enzyme-linked immunosorbent assay. Patients with urine albumin to creatinine ratio (UACR) > 30mg/g from the National Health and Nutrition Survey (NHANES) 2011-2014 were divided into 4 groups according to the quartile of Klotho. Cognitive function was examined using the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Digit Symbol Substitution Test (DSST), and Animal Fluency Test. The relationship between Klotho and cognitive function was analyzed by multivariable regression and subgroup analysis.

Results

Among 368 CKD patients with albuminuria, we found that Klotho was negatively associated with creatinine, and positively associated with hemoglobin, and estimated glomerular filtration rate. No significant linear relationship was showed between Klotho (as a continuous variable) and cognitive function. When regarded Klotho as a category variable, patients in the quartile 3 group were at a better cognitive performance for CEARD-word learning subset and DSST, especially in the CKD patients with 30 mg/g < UACR <300 mg/g, but not in participants with UACR > 300 mg/g.

Conclusions

The increased Klotho was associated with an increased cognitive function in CKD patients with microalbuminuria. Further studies are needed to demonstrate whether Klotho may be a beneficial biomarker of cognitive health and neurodegeneration.

Risk Factors for Incident CKD in Black and White Americans: The REGARDS Study

RATIONALE & OBJECTIVE

Little information exists on the incidence of and risk factors for chronic kidney disease (CKD) in contemporary US cohorts and whether risk factors differ by race, sex, or region in the United States.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

4,198 Black and 7,799 White participants aged at least 45 years, recruited from 2003 through 2007 across the continental United States, with baseline estimated glomerular filtration rate (eGFR)>60mL/min/1.73m2 and eGFR assessed again approximately 9 years later.

EXPOSURES

Age, sex, race (Black or White), region ("stroke belt" or other), education, income, systolic blood pressure, body mass index, diabetes, coronary heart disease, hyperlipidemia, smoking, and albuminuria.

OUTCOMES

(1) eGFR change and (2) incident CKD defined as eGFR<60mL/min/1.73m2 and≥40% decrease from baseline or kidney failure.

ANALYTICAL APPROACH

Linear regression and modified Poisson regression were used to determine the association of risk factors with eGFR change and incident CKD overall and stratified by race, sex, and region.

RESULTS

Mean age of participants was 63±8 (SD) years, 54% were female, and 35% were Black. After 9.4±1.0 years of follow-up, CKD developed in 9%. In an age-, sex-, and race-adjusted model, Black race (β =-0.13; P<0.001) was associated with higher risk of eGFR change, but this was attenuated in the fully adjusted model (β=0.02; P=0.5). Stroke belt residence was independently associated with eGFR change (β =-0.10; P<0.001) and incident CKD (relative risk, 1.14 [95% CI, 1.01-1.30]). Albuminuria was more strongly associated with eGFR change (β of-0.26 vs-0.17; P=0.01 for interaction) in Black compared with White participants. Results were similar for incident CKD.

LIMITATIONS

Persons of Hispanic ethnicity were excluded; unknown duration and/or severity of risk factors.

CONCLUSIONS

Established CKD risk factors accounted for higher risk of incident CKD in Black versus White individuals. Albuminuria was a stronger risk factor for eGFR decrease and incident CKD in Black compared with White individuals. Living in the US stroke belt is a novel risk factor for CKD.

Renal and Electrolyte Disorders and the Nervous System

OBJECTIVE

Neurologic complications are a major contributor to death and disability in patients with renal disease. Oxidative stress, endothelial dysfunction, accelerated arteriosclerosis, and uremic inflammatory milieu affect both the central and peripheral nervous systems. This article reviews the unique contributions of renal impairment to neurologic disorders and their common clinical manifestations as the prevalence of renal disease increases in a globally aging population.

LATEST DEVELOPMENT

Advances in the understanding of the pathophysiologic interplay between the kidneys and brain, also referred to as the kidney-brain axis, have led to more widespread recognition of associated changes in neurovascular dynamics, central nervous system acidification, and uremia-associated endothelial dysfunction and inflammation in the central and peripheral nervous systems. Acute kidney injury increases mortality in acute brain injury to nearly 5 times that seen in matched controls. Renal impairment and its associated increased risks of intracerebral hemorrhage and accelerated cognitive decline are developing fields. Dialysis-associated neurovascular injury is increasingly recognized in both continuous and intermittent forms of renal replacement therapy, and treatment strategies for its prevention are evolving.

ESSENTIAL POINTS

This article summarizes the effects of renal impairment on the central and peripheral nervous systems with special considerations in acute kidney injury, patients requiring dialysis, and conditions that affect both the renal and nervous systems.

[Mobile everyday-life digital technologies for the prevention of Alzheimer's dementia: cognitive health and cognitive safety]

It is generally accepted that the treatment of Alzheimer's disease should be flanked by preventive measures for risk reduction in order to maintain cognitive functions for as long as possible; however, the research and development of treatment concepts are both faced with challenges. The preventive risk reduction necessitates a high level of coordination of neurology and psychiatry with other disciplines. Also, patients must develop a high level of health competence and summon up self-motivation and adherence. This concept article deals with the question of how mobile everyday-life digital technologies can help to address these challenges. The core prerequisite is the interdisciplinary coordinated structuring of prevention with the focus on cognitive health and cognitive safety. Cognitive health relates to a reduction of risk factors associated with lifestyle. Cognitive safety concerns the avoidance of iatrogenic side effects on cognitive functions. Digital technologies that are relevant in this context are mobile apps based on smartphones or tablets for everyday-life and high-frequency recording of cognitive functions, apps that can coach the implementation of lifestyle changes as companion technologies, apps that can assist in the reduction of iatrogenic risks and those that can improve the health competence of patients and relatives. The state of development of such medical products is at different stages of progress. Therefore, this concept article does not provide a review of existing products but rather deals with the fundamental interplay of potential solutions in the prevention of Alzheimer dementia in the areas of cognitive health and cognitive safety.

Cognitive performance is associated with glomerular filtration rate in patients with chronic kidney disease: results from the CKD-REIN cohort

BACKGROUND

Chronic kidney disease (CKD) is associated with cognitive impairment in general population. We assessed the association between kidney and cognitive functions in patients with CKD and the influence of cardiovascular (CV) risk factors, and depression on this association.

METHODS

The CKD-Renal Epidemiology and Information Network cohort included 3033 patients with CKD stages 3-4, followed for 5 years. Cognitive function was assessed with the Mini-Mental State Examination (MMSE) and estimated glomerular filtration rate (eGFR) with the CKD-Epidemiology Collaboration equation-creatinin formula. Evolution of the MMSE score over time and its association with baseline eGFR were investigated with linear mixed models. We assessed the risk of incident cognitive outcome (hospitalisation or death with relevant International Classification of Disease-10 codes), with a Cox proportional hazard model.

RESULTS

The mean age was 66.8, the mean eGFR was 33 mL/min/1.73 m² and 387 patients (13.0%) had an MMSE score below 24 at baseline. A 10 mL/min/1.73 m² decrement of baseline eGFR was associated with a mean MMSE decrease of 0.12 (95% CI 0.04 to 0.19) after adjustment for demographic characteristics, depression, CV risk factors and disease; but baseline eGFR was not associated with MMSE temporal evolution. HR for cognitive outcome during follow-up (median 2.01 years) associated with a 10 mL/min/1.73 m² decrement of baseline eGFR was 1.35 (1.07, 1.70) (p=0.01) after adjustment.

CONCLUSIONS

In patients with CKD, lower eGFR was associated with worse cognitive performance and incident cognitive events, independently of demographics, CV risk factors and depression.

TRIAL REGISTRATION NUMBER

NCT03381950.

Timed-averaged blood pressure showed a J-curve association with stroke in elderly chronic kidney disease patients

BACKGROUND

The risk factors for stroke in elderly patients with chronic kidney disease (CKD) are not well understood. This study aimed to explore the influence of systolic blood pressure (SBP) on the risk of stroke in a large cohort of elderly patients with stage 3-5 CKD.

METHODS

We retrospectively identified 665 patients hospitalized in Beijing Friendship Hospital from January 2000 to December 2021. Patients were followed up until the occurrence of stroke or death. Multivariate logistic regression analysis and Cox proportional hazard models were used to analyze the risk factors for stroke according to the presence or absence of CKD. The association between CKD and stroke was further evaluated regarding the role of SBP in the hypertensive population.

RESULTS

In individuals with CKD, a J-shaped relationship was observed between SBP levels and the risk of stroke. Participants with CKD and an SBP less than 125 mmHg had a significantly higher cumulative stroke survival rate than those whose SBP was between 125 and 139 mmHg. The cumulative stroke survival rate increased progressively for those with SBP higher than 140 mmHg. This J-shaped relationship was not found in patients without CKD.

CONCLUSION

In elderly patients with CKD, those with the lowest BP are at increased risk for incident stroke. This phenomenon could be different from that in the general population.

Chronic kidney disease, physical activity and cognitive function in older adults-results from the National Health and Nutrition Examination Survey (2011-2014)

BACKGROUND

Cognitive impairment is common among persons with chronic kidney disease (CKD), due in part to reduced kidney function. Given that physical activity (PA) is known to mitigate cognitive decline, we examined whether associations between CKD stage and global/domain-specific cognitive function differ by PA.

METHODS

We leveraged 3223 participants (≥60 years of age) enrolled in National Health and Nutrition Examination Survey (NHANES, 2011-2014), with at least one measure of objective cognitive function [immediate recall (CERAD-WL), delayed recall (CERAD-DR), verbal fluency (AF), executive function/processing speed (DSST), global (average of four tests) or self-perceived memory decline (SCD)]. We quantified the association between CKD stage {no CKD: estimated glomerular filtration rate [eGFR] ≥60 mL/min/1.73 m2 and albuminuria [albumin:creatinine ratio (ACR)] <30 mg/g; stages G1-G3: eGFR ≥60 mL/min/1.73 m2 and ACR ≥30 mg/g or eGFR 30-59 mL/min/1.73 m2; stages G4 and G5: eGFR <30 mL/min/1.73 m2} and cognitive function using linear regression (objective measures) and logistic regression (SCD), accounting for sampling weights for nationally representative estimates. We tested whether associations differed by PA [Global Physical Activity Questionnaire, high PA ≥600 metabolic equivalent of task (MET) · min/week versus low PA <600 MET · min/week] using a Wald test.

RESULTS

Among NHANES participants, 34.9% had CKD stages G1-G3, 2.6% had stages G4 and G5 and 50.7% had low PA. CKD stages G4 and G5 were associated with lower global cognitive function {difference = -0.38 standard deviation [SD] [95% confidence interval (CI) -0.62 to -0.15]}. This association differed by PA (Pinteraction = 0.01). Specifically, among participants with low PA, those with CKD stages G4 and G5 had lower global cognitive function [difference = -0.57 SD (95% CI -0.82 to -0.31)] compared with those without CKD. Among those with high PA, no difference was found [difference = 0.10 SD (95% CI -0.29-0.49)]. Similarly, the CKD stage was only associated with immediate recall, verbal fluency, executive function and processing speed among those with low PA; no associations were observed for delayed recall or self-perceived memory decline.

CONCLUSIONS

CKD is associated with lower objective cognitive function among those with low but not high PA. Clinicians should consider screening older patients with CKD who have low PA for cognitive impairment and encourage them to meet PA guidelines.

Chronic kidney disease and cognitive decline in patients with type 2 diabetes at elevated cardiovascular risk

AIMS

We addressed the question whether chronic kidney disease (CKD) may contribute to cognitive decline in type 2 diabetes.

METHODS

Participants with type 2 diabetes with elevated cardiovascular risk or CKD from cognition substudies of two large trials were studied prospectively (CARMELINA: n = 2666, mean ± SD age 68.1 ± 8.7 years, CAROLINA: n = 4296; 64.7 ± 9.4 years). Estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR) at baseline were related to cognitive performance (Mini-Mental State Examination (MMSE) and attention and executive functioning score (A&E)) in linear regression analyses, adjusted for demographics, cardiovascular risk factors and treatment, at baseline and follow-up.

RESULTS

CKD at baseline was more common in CARMELINA than CAROLINA (eGFR<60 in 72.6 % and 19.6 %, macroalbuminuria in 35.0 % and 4.1 %, respectively). Baseline eGFR was related to A&E in CARMELINA (b = 0.02 per 10 ml/min/1.73m², 95%CI [0.01,0.03]). Baseline UACR was related to A&E in CAROLINA (b = -0.01 per doubling of UACR mg/g, 95%CI [-0.02,-0.002]). Baseline UACR predicted decline in A&E in CAROLINA (median 6.1 years follow-up; b = -0.01, 95%CI [-0.03,-0.0001] per doubling of UACR mg/g).

CONCLUSIONS

eGFR and UACR were associated with A&E in two cohorts with type 2 diabetes, enriched for CKD and cardiovascular disease. The small effect size estimates indicate limited impact of kidney dysfunction on cognition in this setting.

GOV IDENTIFIERS

NCT01897532 NCT01243424.

Glymphatic system dysfunction in patients with early chronic kidney disease

Introduction

It is a recent finding that glymphatic system dysfunction contributes to various neurological problems. The purpose of this research was to assess the function of the glymphatic system in neurologically asymptomatic early chronic kidney disease (CKD) patients and healthy controls, using diffusion tensor image analysis along perivascular space (DTI-ALPS) index.

Methods

In a prospective study, we included patients with early CKD who were asymptomatic for neurological issues and obtained clinical and laboratory data. In all participants, brain magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI) was conducted. We used DSI program for DTI preprocessing and DTI-ALPS index estimation. The DTI-ALPS index was compared between patients with early CKD and healthy controls, and the association between clinical characteristics and the DTI-ALPS index was investigated.

Results

Eighteen patients with early CKD and 18 healthy controls were included in this study. Patients with early CKD had lower DTI-ALPS index than healthy controls (1.259 ± 0.199 vs. 1.477 ± 0.232, p = 0.004). In the correlation analysis, the DTI-ALPS index had no significant relationship with other clinical factors.

Conclusion

We suggest dysfunction of glymphatic system in patients with early chronic kidney disease using the DTI-ALPS index. This may be related to the pathophysiology of neurological problems including impairment of cognition in patients with early CKD.

Insights into Cognitive Brain Health in Chronic Kidney Disease

Cognitive impairment and Chronic Kidney Disease (CKD) are common in older adults. With advances in medicine, the average lifespan is expected to increase, further increasing the prevalence of both conditions. The mechanisms underlying cognitive impairment in CKD are unclear. While mild-moderately low estimated glomerular filtration rate (eGFR) may not be associated with cognitive impairment, severely decreased eGFR and albuminuria do. Patients on dialysis have a high prevalence of cognitive impairment. Cognitive function improves after kidney transplantation. However, some residual cognitive deficits persist after transplantation, indicating that restoring the kidney function alone may not be enough to restore cognitive function, and other etiological factors may play a role. Albuminuria, another marker of CKD is also associated with cognitive impairment. However, albuminuria is often undiagnosed. Improving early identification and management of patients with albuminuria may be a good population-based dementia prevention strategy. Other factors associated with cognitive impairment in CKD include anemia and other metabolic derangements commonly observed in CKD. In this article, we reviewed the prevalence of cognitive impairment in CKD, the potential mechanisms underlying cognitive impairment in CKD, andthecurrent evidence on the association between cognitive impairment and eGFR and albuminuria.