A new approach for cognitive impairment pattern in chronic kidney disease

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Emotional Intelligence in Hemodialysis Patients: The Impact of an Intradialytic Exercise Training Program

The current study aimed to investigate whether there is a relationship between emotional intelligence (EI), functional capacity, fatigue, cognitive function, and quality of life (QoL) in HD patients and to assess the effect of a 9-month intradialytic exercise training program on EI levels. Seventy-eight dialysis patients (50 M/28 F, 60.6 ± 17.2 years) participated in the cross-sectional study. Afterward, a subgroup of 18 patients (15 M/3 F, 56.7 ± 12.3 years) completed a 9-month supervised intradialytic exercise training program (three times weekly). EI was assessed by the Schutte Self Report Emotional Intelligence Test (SSEIT) and the Wong and Law Emotional Intelligence Scale (WLEIS). Functional capacity was assessed by a battery of tests. Sleep quality, depression levels, and daily sleepiness were assessed via validated questionnaires. All assessments were carried out before and after the intervention. A significant positive correlation was found between the WLEIS scores and the physical component summary of the QoL questionnaire. In contrast, the WLEIS scores were negatively associated with general and physical fatigue. The SSEIT scores were positively associated with cognitive function. After nine months of exercise training, only the group with low WLEIS scores improved their EI score significantly compared to the baseline values (98.7 ± 7.0 vs. 73.0 ± 4.0, p = 0.020), while no changes were observed in the medium or high EI groups. In conclusion, patients with higher levels of EI showed increased quality of life and lower levels of fatigue. Patients with low levels of EI are more likely to benefit from an exercise training program compared to their medium- and high-level counterparts.

[Neurocognitive disorders in chronic kidney disease]

Neurocognitive disorders (NCD) are common in patients with chronic kidney disease (CKD). It is essential to identify and characterize these disorders at an early stage, so as to be able to offer appropriate treatment. In a chronic disease such as CKD, the patient's involvement in decision-making is a major challenge, given the prospects for suppletive treatment: hemodialysis, peritoneal dialysis, kidney transplantation or non-dialytic drug therapy. Many factors are associated with the development and progression of NCD in patients with CKD, and a variety of conditions can influence the outcome of cognitive assessment in these patients.

[Neuropsychological impairments in patients undergoing peritoneal dialysis treatment]

BACKGROUND

Patients with chronic kidney disease on hemodialysis (HD) often have cognitive deficits. However, there are few studies that have examined the neuropsychological impairments of patients receiving peritoneal dialysis (PD).

METHODS

Executive functions, processing speed and verbal memory were assessed in 27 PD patients, 42 HD patients, and 42 healthy participants (HP). Systolic blood pressure and total time on renal replacement therapy (RRT) were controlled statistically. Associations between performance and clinical factors were analyzed using correlations and multiple regression.

RESULTS

The DP group showed better performance compared to the HD group in verbal fluency, working memory, cognitive flexibility, planning and decision making. The DP group showed worse execution than the HP group in verbal inhibition and memory. Executive function scores were positively associated with total months on PD, total months on RRT, total months on HD, albumin, total cholesterol, and phosphorus, and negatively with ferritin.

CONCLUSION

Global executive functioning was more optimal in PD patients than in HD patients. The results show the positive effect of PD on executive functions, which must be taken into account when choosing the TRS. The associations observed between biochemical factors and performance show the importance of maintaining an adequate nutritional status in these patients.

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.

Neurocognitive Function Changes Following Kidney Transplant: A Prospective Study

Rationale & Objective

Patients with advanced kidney disease are at risk for cognitive impairment, which may persist after kidney transplantation. We sought to understand changes in neurocognitive function domains utilizing comprehensive cognitive assessments.

Study Design

Prospective cohort study.

Setting & Population

Single-center study of patients undergoing kidney transplantation.

Exposure

Kidney transplantation.

Outcomes

Changes in neurocognitive function as measured by the Repeatable Battery for Assessment of Neuropsychological Status (RBANS) and the Trail Making Test Parts A and B (TRAIL A and B) before transplantation (baseline) and compared to 3 months and 12 months posttransplant.

Analytical Approach

Wilcoxon signed-rank and linear mixed effect models were utilized to assess changes in neurocognitive scores at 3 months and 12 months compared to baseline.

Results

Thirty-two patients were included with a mean age of 45 years, 47% female, 85% White, and 62% with at least some college education. Hypertension and diabetes were etiologies of kidney disease in 31% and 25% of patients, respectively. Baseline RBANS and TRAIL A and B scores averaged 84.7 ± 14, 40.4 ± 9.9, and 41 ± 11.5, respectively. Although there were posttransplant improvements in immediate and delayed memory at 3 months, these were not sustained at 12 months. There were no significant differences from baseline at 3 months and 12 months in RBANS index scores for language, visuospatial/constructional abilities, and attention. Compared to baseline, TRAIL A scores were not significantly different at 3 months but were significantly improved at 12 months, whereas TRAIL B scores improved significantly at both 3 months and 12 months.

Limitations

Single-center design and small sample size.

Conclusions

Utilizing comprehensive cognitive assessments, we found improvements in attention and executive function in the first posttransplant year as measured by TRAIL A and B. However, there was no significant change in global cognition as measured by RBANS. These findings identify cognitive domains for potential intervention in the posttransplant population.

Reversal of neurovascular decoupling and cognitive impairment in patients with end-stage renal disease during a hemodialysis session: Evidence from a comprehensive fMRI analysis

Neurovascular (NV) decoupling is a potential neuropathologic mechanism of cognitive impairment in patients with end-stage renal disease (ESRD). Hemodialysis improves cognitive impairment at 24 h post-dialysis, which suggests a potential neuroprotective effect of hemodialysis treatment on the brain. We investigated the effects of hemodialysis treatment on the reversal of NV decoupling associated with cognitive improvement. A total of 39 patients with ESRD and 39 healthy controls were enrolled. All patients were imaged twice during a dialysis session: before hemodialysis (T1_pre-dialysis ) and at 24 h after dialysis (T2_{post-dialysis} ). The healthy controls were imaged once. NV coupling was characterized based on correlation coefficients between four types of blood oxygen level-dependent signals and cerebral blood flow (CBF). A battery of neuropsychological and blood tests was performed before the imaging. Patients with ESRD showed improvements in memory and executive function at T2_{post-dialysis} compared with that at T1_pre-dialysis . At both T1_pre-dialysis and T2_{post-dialysis} , patients with ESRD had lower amplitude of low-frequency fluctuation (ALFF)-CBF coupling than healthy controls. Additionally, patients with ESRD had higher ALFF-CBF coupling at T2_{post-dialysis} than at T1_pre-dialysis . Higher memory scores, higher hemoglobin level, lower total plasma homocysteine level, lower systolic blood pressure variance, and lower ultrafiltration volume were associated with higher ALFF-CBF coupling in patients with ESRD after a hemodialysis session. These findings indicate that partial correction of anemia and hyperhomocysteinemia, stable systolic blood pressure, and fluid restriction may be closely linked to the reversal of NV decoupling and improvement in cognition in patients with ESRD.

Cognitive Impairment in End Stage Renal Disease Patients Undergoing Hemodialysis: Markers and Risk Factors

(1) Background: Cognitive impairment (CI) is common in chronic kidney disease (CKD) and patients treated with hemodialysis. (2) Methods: The systematic review was prepared following the PRISMA statement (2013). The biomedical electronic databases MEDLINE and SCOPUS were searched. (3) Results: out of 1093 studies, only 30, which met problem and population criteria, were included in this review. The risk factors for CI can be divided into three groups: traditional risk factors (present in the general population), factors related to dialysis sessions, and nontraditional risk factors occurring more frequently in the HD group. (4) Conclusions: the methods of counteracting CI effective in the general population should also be effective in HD patients. However, there is a need to develop unique anti-CI approaches targeting specific HD risk factors, i.e., modified hemodialysis parameters stabilizing cerebral saturation and blood flow.

Chronic kidney disease and neurological disorders: are uraemic toxins the missing piece of the puzzle?

Chronic kidney disease (CKD) perturbs the crosstalk with others organs, with the interaction between the kidneys and the heart having been studied most intensively. However, a growing body of data indicates that there is an association between kidney dysfunction and disorders of the central nervous system. In epidemiological studies, CKD is associated with a high prevalence of neurological complications, such as cerebrovascular disorders, movement disorders, cognitive impairment and depression. Along with traditional cardiovascular risk factors (such as diabetes, inflammation, hypertension and dyslipidaemia), non-traditional risk factors related to kidney damage (such as uraemic toxins) may predispose patients with CKD to neurological disorders. There is increasing evidence to show that uraemic toxins, for example indoxyl sulphate, have a neurotoxic effect. A better understanding of factors responsible for the elevated prevalence of neurological disorders among patients with CKD might facilitate the development of novel treatments. Here, we review (i) the potential clinical impact of CKD on cerebrovascular and neurological complications, (ii) the mechanisms underlying the uraemic toxins' putative action (based on pre-clinical and clinical research) and (iii) the potential impact of these findings on patient care.

"Is It Removed During Dialysis?"-Cognitive Dysfunction in Advanced Kidney Failure-A Review Article

Cognitive impairment is independently associated with kidney disease and increases in prevalence with declining kidney function. At the stage where kidney replacement therapy is required, with dialysis or transplantation, cognitive impairment is up to three times more common, and can present at a younger age. This is not a new phenomenon. The cognitive interactions of kidney disease are long recognized from historical accounts of uremic encephalopathy and so-called "dialysis dementia" to the more recent recognition of cognitive impairment in those undergoing kidney replacement therapy (KRT). The understanding of cognitive impairment as an extra-renal complication of kidney failure and effect of its treatments is a rapidly developing area of renal medicine. Multiple proposed mechanisms contribute to this burden. Advanced vascular aging, significant multi-morbidity, mood disorders, and sleep dysregulation are common in addition to the disease-specific effects of uremic toxins, chronic inflammation, and the effect of dialysis itself. The impact of cognitive impairment on people living with kidney disease is vast ranging from increased hospitalization and mortality to decreased quality of life and altered decision making. Assessment of cognition in patients attending for renal care could have benefits. However, in the context of a busy clinical service, a pragmatic approach to assessing cognitive function is necessary and requires consideration of the purpose of testing and resources available. Limited evidence exists to support treatments to mitigate the degree of cognitive impairment observed, but promising interventions include physical or cognitive exercise, alteration to the dialysis treatment and kidney transplantation. In this review we present the history of cognitive impairment in those with kidney failure, and the current understanding of the mechanisms, effects, and implications of impaired cognition. We provide a practical approach to clinical assessment and discuss evidence-supported treatments and future directions in this ever-expanding area which is pivotal to our patients' quality and quantity of life.

Cognitive disorders in patients with chronic kidney disease: specificities of clinical assessment

Neurocognitive disorders are frequent among chronic kidney disease (CKD) patients. Identifying and characterizing cognitive impairment (CI) can help to assess the ability of adherence to CKD risk reduction strategy, identify potentially reversible causes of cognitive decline, modify pharmacotherapy, educate the patient and caregiver and provide appropriate patient and caregiver support. Numerous factors are associated with the development and progression of CI in CKD patients and various conditions can influence the results of cognitive assessment in these patients. Here we review clinical warning signs that should lead to cognitive screening; conditions frequent in CKD at risk to interfere with cognitive testing or performance, including specificities of cognitive assessment in dialysis patients or after kidney transplantation; and available tests for screening and observed cognitive patterns in CKD patients.

Cognitive performance in dialysis patients - "when is the right time to test?"

Background

Cognitive impairment in chronic kidney disease, especially in end stage renal disease, is a public health problem. Nevertheless, the cause of chronic kidney disease still remains unclear. A prevalence of cognitive impairment in patients with end stage renal disease of up to 87% has been found.

Methods

The study at hand deals with the research on the – potential – effect of timing on cognitive performance when testing cognitive impairment in hemodialysis patients during the dialysis cycle. We tested cognitive performance with a neuropsychological test battery (RBANS, Repeatable Battery for the Assessment of Neuropsychological Status) on two occasions while patients were on dialysis as well as on a dialysis-free day. In addition, all participants were rated using the Geriatric Depression Scale (GDS) and several demographic and clinical variables were recorded in order to investigate their possible influence on cognitive performance.

The patients were recruited in three dialysis centers in the central region of Hesse, Germany. Twenty-six participants completed the 3 testings during a period of 6 weeks. The testing was carried out in the dialysis centers.

Results

Looking at the total scale score, patients achieved the best cognitive performance in the RBANS during the first 2 h on dialysis with 81.1 points. When comparing the scores of the three measurement occasions (first 2 h, Timepoint 1 vs. last 2 h, Timepoint 2 vs. dialysis free day, Timepoint 3, however, no significant difference in the total scale score was detected. But patients showed significantly better cognitive performance in language in the first 2 h (p < 0.001) as well as in the last 2 h (p < 0.001) compared with the dialysis-free day.

Conclusion

Due to the high prevalence of cognitive impairment, there is an increasing need to assess cognitive function in dialysis patients. Our data show that the time point of testing (first 2 h on hemodialysis vs. last 2 h on hemodialysis vs. Hemodialysis free day) had no influence of cognitive function in hemodialysis patients in routine indications.

Cerebral Perfusion in Hemodialysis Patients: A Feasibility Study

Background

Patients on hemodialysis (HD) are known to exhibit low values of regional cerebral oxygenation (rSO2) and impaired cognitive functioning. The etiology of both is currently unknown.

Objective

To determine the feasibility of serially monitoring rSO2 in patients initiating HD. In addition, we sought to investigate how rSO2 is related to hemodynamic and dialysis parameters.

Design

Prospective observational study.

Setting

Single-center tertiary academic teaching hospital in Ontario, Canada.

Participants

Six patients initiating HD were enrolled in the study.

Methods

Feasibility was defined as successful study enrollment (>1 patient/month), successful consent rate (>70%), high data capture rates (>90%), and assessment tolerability. Regional cerebral oxygenation monitoring was performed 1 time/wk for the first year of dialysis. A neuropsychological battery was performed 3 times during the study: before dialysis initiation, 3 months, and 1 year after dialysis initiation. The neuropsychological battery included a traditional screening tool: the Repeatable Battery for the Assessment of Neuropsychological Status, and a robot-based assessment: Kinarm.

Results

Our overall consent rate was 33%, and our enrollment rate was 0.4 patients/mo. In total 243 rSO2 sessions were recorded, with a data capture rate of 91.4% (222/243) across the 6 patients. Throughout the study, no adverse interactions were reported. Correlations between rSO2 with hemodynamic and dialysis parameters showed individual patient variability. However, at the individual level, all patients demonstrated positive correlations between mean arterial pressure and rSO2. Patients who had more than 3 liters of fluid showed significant negative correlations with rSO2. Less cognitive impairment was detected after initiating dialysis.

Limitation

This small cohort limits conclusions that can be made between rSO2 and hemodynamic and dialysis parameters.

Conclusions

Prospectively monitoring rSO2 in patients was unfeasible in a single dialysis unit, due to low consent and enrollment rates. However, rSO2 monitoring may provide unique insights into the effects of HD on cerebral oxygenation that should be further investigated.

Trial Registration

Due to the feasibility nature of this study, no trial registration was performed.

Abnormal rich club organization in end-stage renal disease patients before dialysis initiation and undergoing maintenance hemodialysis

Background

End-stage renal disease (ESRD) patients are at a substantially higher risk for developing cognitive impairment compared with the healthy population. Dialysis is an essential way to maintain the life of ESRD patients. Based on previous research, there isn’t an uncontested result whether cognition was improved or worsened during dialysis.

Methods

To explore the impact of dialysis treatment on cognitive performance, we recruited healthy controls (HCs), predialysis ESRD patients (predialysis group), and maintenance hemodialysis ESRD patients (HD group). All ESRD patients performed six blood biochemistry tests (hemoglobin, urea, cystatin C, Na+, K+, and parathyroid hormone). Neuropsychological tests were used to measure cognitive function. By using diffusion tensor imaging and graph-theory approaches, the topological organization of the whole-brain structural network was investigated. Generalized linear models (GLMs) were performed to investigate blood biochemistry predictors of the neuropsychological tests and the results of graph analyses in the HD group and predialysis group.

Results

Neuropsychological analysis showed the HD group exhibited better cognitive function than the predialysis group, but both were worse than HCs. Whole-brain graph analyses revealed that increased global efficiency and normalized shortest path length remained in the predialysis group and HD group than the HCs. Besides, a lower normalized clustering coefficient was found in the predialysis group relative to the HCs and HD group. For the GLM analysis, only the Cystatin C level was significantly associated with the average fiber length of rich club connections in the predialysis group.

Conclusions

Our study revealed that dialysis had a limited effect on cognitive improvement.

Association between Dialysis Adequacy and Cognition in Patients with Peritoneal Dialysis

OBJECTIVE

Cognition of peritoneal dialysis patients is influenced by various factors including dialysis adequacy such as fractional urea clearance (Kt/V) and relative overhydration (RelOH). This study aimed to discover the potential contribution of dialysis adequacy to cognitive function in patients undergoing peritoneal dialysis.

METHODS

Fifty-nine patients undergoing peritoneal dialysis were recruited. Demographic information, comorbidities, and clinical lab findings were retrospectively collected, and dialysis adequacy was determined by the Kt/V and RelOH calculation. Cognition and depression were measured with Digit Symbol Substitution Test, Hopkins Verbal Learning Test, Wechsler memory scale (spatial span), Wisconsin Card Sorting Test, and Beck's depression inventory. Partial correlation test was used to explore the correlation of dialysis adequacy with cognitive function.

RESULTS

RelOH showed significant correlation with some of the Wisconsin Card Sorting test results. The categories achieved showed negative correlation (r=-0.32, p=0.02) and trials to complete first category showed positive correlation (r=0.31, p=0.02) with RelOH. Other tasks showed no significant correlation with RelOH. Kt/V.

CONCLUSION

Our study demonstrates that peritoneal dialysis adequacy, measured by RelOH, seems to be significantly correlated with the occurrence of cognitive impairment. The outcome suggests that RelOH may have the potential to clarify the role of cognitive impairment in peritoneal dialysis patients.

Sensitivity and specificity of the Brazilian version of the Montreal Cognitive Assessment - Basic (MoCA-B) in chronic kidney disease

INTRODUCTION

Cognitive impairment in chronic kidney disease (CKD) is commonly associated with neuropsychiatric disorders. As a complex pathology, at all stages of CKD patients need to have a good understanding of the need for drug and nutritional adherence. Cognitive screening is the starting point for detection of cognitive impairments.

OBJECTIVE

To determine the specificity and sensitivity of the Brazilian Portuguese version of the Montreal Cognitive Assessment - Basic (MoCA-B) for identification of cognitive impairment in the CKD population.

METHODS

This was a cross-sectional study with 163 CKD patients undergoing hemodialysis treatment. The Mini-Mental State Examination (MMSE) and MoCA-B were administered.

RESULTS

The MoCA-B has reliable internal consistency (Cronbach's alpha = 0.74). A cutoff point of ≤ 21 points provides the best sensitivity and specificity for detection of cognitive impairment. The education variable had less impact on the total MoCA-B score than on the total MMSE score.

CONCLUSIONS

The MoCA-B is a suitable screening instrument for evaluating the global cognition of hemodialysis patients. The results can help health professionals to conduct evaluations and plan clinical management.

A Study of Executive Function in Patients with Chronic Kidney Disease before and after a Single Session of Hemodialysis

Background  Executive functions (EFs) are critical to daily life and sensitive to our physiological functioning and emotional states. The number of people living with chronic kidney disease (CKD) on hemodialysis (HD) globally is increasing steadily. We aimed to determine the impact of a single session of HD on EFs in patients with CKD receiving maintenance HD (MHD). Methods  This was a quasi-experimental study conducted at the department of psychiatry and dialysis unit of a tertiary hospital. Patients undergoing MHD underwent screening to rule out delirium, using the Confusion Assessment Method prior to EF testing. The tests of EF used were the Trail-Making Test-Part B (TMT-B) and Frontal Assessment Battery (FAB), both of which were administered before and after a session of HD. Statistical tests used were Wilcoxon matched pairs signed ranks test, paired t -test, single sample t -test, and correlation analyses. Results  The mean time taken on TMT-B before HD was 195.36 seconds and after HD, 171.1 seconds; difference is significant ( p = 0.0001). The mean FAB score was 13.19 before HD and 14.83 after HD; the difference is significant ( p < 0.0001). Significant differences were observed on similarities (p = 0.003), lexical fluency (p = 0.02), and go-no go ( p = 0.003) subtests of FAB. Mean TMT-B scores before and after HD differed significantly from that of a reference study (reference TMT-B 150.69 seconds), p = 0.0002 and 0.04, respectively. Conclusion  We conclude that patients with CKD on MHD, in general, have worse executive cognitive functioning compared with healthy populations. A session of HD results in significant improvement in these functions.

Temporising and respect for patient self-determination

The principle of self-determination plays a crucial role in contemporary clinical ethics. Somewhat simplified, it states that it is ultimately the patient who should decide whether or not to accept suggested treatment or care. Although the principle is much discussed in the academic literature, one important aspect has been neglected, namely the fact that real-world decision making is temporally extended, in the sense that it generally takes some time from the point at which the physician (or other health care professional) determines that there is a decision to be made and that the patient is capable of making it, to the point at which the patient is actually asked for his or her view. This article asks under what circumstances, if any, temporising-waiting to pose a certain treatment question to a patient judged to have decision-making capacity-is compatible with the principle of self-determination.

Investigating the Relationship between Cerebral Blood Flow and Cognitive Function in Hemodialysis Patients

BACKGROUND

The immediate and longer-term effects of hemodialysis on cerebral circulation, cerebral structure, and cognitive function are poorly understood.

METHODS

In a prospective observational cohort study of 97 adults (median age 59 years) receiving chronic hemodialysis, we used transcranial Doppler ultrasound to measure cerebral arterial mean flow velocity (MFV) throughout dialysis. Using a well validated neuropsychological protocol, we assessed cognitive function during and off dialysis and after 12 months of treatment. We also used brain magnetic resonance imaging (MRI) to assess atrophy, white matter hyperintensities (WMHs), and diffusion parameters, and tested correlations between MFV, cognitive scores, and changes on MRI.

RESULTS

MFV declined significantly during dialysis, correlating with ultrafiltrate volumes. Percentage of decline in MFV correlated with intradialytic decline in cognitive function, including global function, executive function, and verbal fluency. At follow-up, 73 patients were available for repeat testing, 34 of whom underwent repeat MRI. In a subgroup of patients followed for 12 months of continued dialysis, percentage of decline in MFV correlated significantly with lower global and executive function and with progression of WMH burden (a marker of small vessel disease). Twelve of 15 patients who received renal transplants during follow-up had both early and follow-up off-dialysis assessments. After transplant, patients' memory (on a delayed recall test) improved significantly; increased fractional anisotropy of white matter (a measure of cerebral diffusion) in these patients correlated with improving executive function.

CONCLUSIONS

Patients undergoing hemodialysis experience transient decline in cerebral blood flow, correlating with intradialytic cognitive dysfunction. Progressive cerebrovascular disease occurred in those continuing dialysis, but not in transplanted patients. Cognitive function and cerebral diffusion improved after transplant.

Recent History of Serious Fall Injuries and Posttransplant Outcomes Among US Kidney Transplant Recipients

BACKGROUND

Serious fall injuries are associated with poor outcomes among dialysis patients, but whether these associations hold in patients with a history of serious fall injury before kidney transplantation is unknown.

METHODS

In national administrative data, 22 474 US adults receiving a first kidney transplant in 2011-2014 with at least 1 year of follow-up before transplant were identified. Serious fall injuries in the year before transplant were identified using diagnostic codes for falls and simultaneous fractures, dislocations, or head trauma in inpatient or outpatient claims. We used multivariable Cox proportional hazards models to estimate associations of incident posttransplant outcomes with serious fall injury in the year before transplant.

RESULTS

A total of 620 (2.8%) recipients had serious fall injuries before transplant and were more likely to be white, female, and have more comorbid conditions than those without a fall injury. Although posttransplant recipient survival did not differ by recent serious fall injuries (hazard ratio [HR], 1.03; 95% confidence interval [CI], 0.78-1.36), these injuries were associated with 33% higher rates of graft failure (HR, 1.33; 95% CI, 1.03-1.72). Patients with serious fall injuries spent 12.1% of posttransplant follow-up hospitalized, a 3.3-fold higher rate than those without a fall, and had nearly 2-fold higher rates of skilled nursing facility utilization (HR, 1.98; 95% CI, 1.52-2.57).

CONCLUSIONS

Serious fall injuries are independently associated with significantly greater resource requirements and lower graft survival. Further study is needed to delineate the relationship between falls and adverse outcomes in transplant and reduce the incidence and deleterious effects of these events.

Comparison of the montreal cognitive assessment and the mini-mental state examination as screening tests in hemodialysis patients without symptoms

Cognitive impairment in end-stage renal disease patients is associated with an increased risk of mortality. We examined the cognitive function in hemodialysis (HD) patients and compared the Korean versions of the Montreal Cognitive Assessment (K-MoCA) and of the Mini-Mental State Examination (K-MMSE) to identify the better cognitive screening instrument in these patients. Thirty patients undergoing hemodialysis and 30 matched reference group of apparently healthy control were included. All subjects underwent the K-MoCA, K-MMSE and a neuropsychological test battery to measure attention, visuospatial function, language, memory and executive function. All cognitive data were converted to z-scores with appropriate age and education level prior to group comparisons. Cognitive performance 1.0 SD below the mean was defined as modest cognitve impairment while 1.5 below the mean was defined as severe cognitive impairment. Modest cognitive impairment in memory plus other cognitive domains was detected in 27 patients (90%) while severe cognitive impairment in memory plus other cognitive domains was detected in 23 (77%) patients. Total scores in the K-MoCA were significantly lower in HD patients than in the reference group. However, no significant group difference was found in the K-MMSE. The K-MMSE ROC AUC (95% confidence interval) was 0.72 (0.59–0.85) and K-MoCA ROC AUC was 0.77 (0.65–0.89). Cognitive impairment is common but under-diagnosed in this population. The K-MoCA seems to be more sensitive than the K-MMSE in HD patients.

Executive function in end-stage renal disease: Acute effects of hemodialysis and associations with clinical factors

Objective

There is evidence of cognitive impairment in patients with end-stage renal disease in hemodialysis (ESRD-HD). However, few studies have exhaustively analyzed executive functions (EFs) in this population, especially considering the influence of a wide range of clinical variables. This study analyzes performance in different EF components in ESRD-HD patients compared to a group of healthy controls (HCs), in addition to the acute effects of HD and the associations of cognitive performance with clinical variables.

Method

EFs were evaluated pre- and post-HD in 43 ESRD-HD patients and 42 HCs, using a battery of tests designed to assess EF domains. Age, schooling, mood and blood pressure were statistically controlled. Associations between performance and clinical factors were computed by correlations and hierarchical multiple regression analyses.

Results

The performance of the ESRD-HD patients was significantly lower than that of HCs in all the EF domains except for planning. Group differences were marginally significant for reasoning. HD produced no acute changes in global performance, with improvements see only in inhibition and working memory. EF scores were positively associated with total number of months previously transplanted, body mass index (BMI), dry weight, and levels of hemoglobin, albumin, ferritin, calcium, phosphorus, sodium, urea, and creatinine.

Conclusions

Global EF functioning was lower in ESRD-HD patients than in HCs. No major acute HD-related EF changes were detected. These findings underline the importance of an adequate nutritional status for maintaining executive functioning in ESRD-HD patients.

The specific impact of uremic toxins upon cognitive domains: a review

One of the mechanisms proposed for chronic kidney disease (CKD)-related cognitive impairment is the accumulation of uremic toxins due to the deterioration of the renal clearance function. Cognition can be categorized into five major domains according to its information processing functions: memory, attention, language, visual-spatial, and executive. We performed a review using the terms 'uric acid', 'indoxyl sulfate', 'p-cresyl sulfate', 'homocysteine', 'interleukins' and 'parathyroid hormone'. These are the compounds that were found to be strongly associated with cognitive impairment in CKD in the literature. The 26 selected articles point towards an association between higher levels of uric acid, homocysteine, and interleukin 6 with lower cognitive performance in executive, attentional, and memory domains. We also reviewed the hemodialysis effects on cognition. Hemodialysis seems to contribute to an amelioration of CKD-related encephalopathic dysfunction, although this improvement occurs more in some cognitive domains than in others.

Does inflammation affect outcomes in dialysis patients?

Chronic, low-grade inflammation is a common comorbid condition in chronic kidney disease (CKD), and particularly in chronic dialysis patients. In this review, we consider the question of whether inflammation affects outcomes in dialysis patients. Levels of proinflammatory cytokines, as well as C-reactive protein, are elevated in chronic dialysis patients. Multiple factors likely contribute to chronic inflammatory activation in kidney disease patients including the uremic milieu, lifestyle and epigenetic influences, infectious and thrombotic events, the dialysis process, and dysbiosis. Increased inflammatory markers in both CKD and chronic dialysis patients are associated with adverse clinical outcomes including all-cause mortality, cardiovascular events, kidney disease progression, protein energy wasting and diminished motor function, cognitive impairment, as well as other adverse consequences including CKD-mineral and bone disorder, anemia, and insulin resistance. Strategies that have been shown to reduce chronic systemic inflammation in CKD and chronic dialysis patients include both pharmacological and nonpharmacological interventions. However, despite evidence that systemic inflammatory markers can be lowered in kidney disease patients treated with various strategies, evidence that this improves clinical outcomes is largely unavailable and represents an important future research direction. Overall, there is strong observational evidence that inflammation is high in chronic dialysis patients and that this is independently associated with numerous adverse clinical outcomes. Targeting inflammation represents a potentially novel and attractive strategy if it can indeed improve adverse outcomes common in this population.

Cognitive Function Declines Significantly during Haemodialysis in a Majority of Patients: A Call for Further Research

INTRODUCTION

Cognitive impairment (CI) is very common condition that occurs in haemodialysis patients and it is associated with reduced functional capacity and mortality. We assessed the change in cognitive function during haemodialysis and associated risk factors.

METHODS

All patients ≥50 years, on haemodialysis for ≥3 months, no dementia from 2 dialysis centres were selected. Cognition was assessed before and after a haemodialysis session using parallel versions of the Montreal Cognitive Assessment (MOCA) tool. Multiple regression was used to examine potential confounders.

RESULTS

Eight-two patients completed both tests - median age 73 (52-91) years, 59% male, dialysis vintage 41 (3-88) months. Sixty-two (76%) had CI at baseline. Cognition declined over dialysis (MOCA 21 ± 4.8 to 19.1 ± 4.1, p < 0.001) and domains affected were attention, language, abstraction and delayed recall. Age and dialysis vintage were independently associated with decline.

CONCLUSION

Cognitive function declines over a haemodialysis session and this has significant clinical implications over health literacy, self-management and tasks like driving. More research is needed to find the cause for this decline in cognition.

Cerebral ischemia during hemodialysis-finding the signal in the noise

Hemodialysis patients have multiple risk factors for small vessel cerebrovascular disease and cognitive dysfunction. Hemodialysis itself may cause clinically significant neurological injury through repetitive cerebral ischemia. However, supporting evidence to date consists of epidemiological associations, expert opinion, and small, single-centre studies of variable methodological quality. Isolating the impact of intra-dialytic hemodynamic instability from underlying renal and vascular disease on clinically relevant functional outcomes would require very large, controlled studies, given the heterogeneity and confounding comorbidities of the population, and the complex relationship between blood pressure and cerebral oxygen delivery. There has been an increase in complementary physiological studies looking directly at intra-dialytic cerebral oxygen balance, which have provided supporting evidence for the occurrence of cerebral ischemia, often independently of hemodynamics. Data suggesting a relationship between these measures of oxygen balance and functional outcomes is only hypothesis-generating at this stage. We advocate the testing of interventions that aim to reduce intra-dialytic cerebral hypoxia (rather than hypotension) in sufficiently powered studies, followed by correlation with validated, longitudinal assessment of clinically relevant neurological damage.

The effect of the interdialytic interval on cognitive function in patients on haemodialysis

BACKGROUND

Cognitive deficits are common among individuals on haemodialysis (HD). The degree of dysfunction may shift over the course of the interdialytic interval.

OBJECTIVES

To use ecological momentary assessment (EMA) to examine the relationship between the length of the interdialytic interval and reports of cognitive dysfunction.

DESIGN

A quantitative study whereby each patient's cognitive functioning was measured during both short and long interdialytic intervals.

PARTICIPANTS

Adults maintained on HD (Female n = 15, Male n = 11; M_Age  = 42.7 ± 15.8 years) were drawn from a standalone HD unit within a large university medical centre.

MEASUREMENTS

Tests of baseline neurocognitive functioning were undertaken (Mini-Mental Status Examination, Digit Span, California Verbal Learning Test, Benton Visual Retention Test, Trail-Making Test) and smartphone-based electronic diary reports of cognitive impairment were made around six times each day for one week.

RESULTS

Cognitive function and aptitude in this sample, although low, did not reflect clinically-significant impairment, with a mean Mini-Mental Status Exam score of 25.7 ± 3.0. Diary reports of cognitive impairment were also minimal, with an overall mean rating of .22 out of 5. Contrary to expectations, cognitive impairment was significantly greater on the one-day interdialytic days than on Day 2 of the two-day interdialytic interval (β = .094, p = .017).

CONCLUSIONS

Although cognitive impairment appears to be mild in stable, young patients with end stage renal disease, volumetric disruptions caused by HD may exacerbate such dysfunction.

Peritoneal dialysis is associated with better cognitive function than hemodialysis over a one-year course

Impaired cognitive functioning in patients with end-stage renal disease may reduce their capabilities to adhere to complex medical or dietary regimens and to fully participate in medical decisions. With decreasing renal function, cognitive abilities are likely to decline, with cognitive dysfunction improving after initiation of dialysis and even being generally reversible after successful renal transplantation. However, little is known about cognitive changes particularly regarding different treatment modalities. To gain further insight into this, we focused on a one-year course of cognitive functions, comparing peritoneal to hemodialysis patients. Within the CORETH-project, two validated neurocognitive tests, assessing executive functioning (Trail Making Test-B) and attention (d2-Revision-Test) and the self-reported Kidney Disease Quality of Life Short Form Cognitive Function-subscale, were administered to 271 patients at baseline and after one year. Subsamples were matched by propensity score, adjusting for age, comorbidity, education, and employment status for 96 hemodialysis and 101 peritoneal dialysis patients. The effects of time and treatment modality were investigated, controlling for well-known confounders. Both tests revealed improvement over one year. Peritoneal dialysis was associated with better outcomes than hemodialysis at baseline and follow-up, but comparability between groups may be limited. The opposite pattern applied to self-reporting. Hemodialysis patients had to be excluded from cognitive testing more often than peritoneal dialysis patients. As such, the number of exclusions may have biased the findings, limiting generalizability. Thus, our findings suggest an improvement of cognitive functioning and support previous indications for peritoneal dialysis being associated with better cognitive functions during a one-year course than hemodialysis.

Effect of renal transplantation on cognitive function in hemodialysis patients: a longitudinal study

BACKGROUND

The literature notes high prevalence of cognitive function (CF) impairment among hemodialysis patients. Renal transplantation by reversing metabolic factors should improve cognitive function; however, results in post-transplant patients are inconsistent. Lack of longitudinal studies, variable and small patient population, variable renal function and post-transplantation period and use of non-specific tests make results difficult to interpret. We looked at CF in stable hemodialysis patients just prior to live renal transplantation and approximately 3 months subsequently using well-validated electrophysiological study of P300 cognitive potential obtained by auditory oddball paradigm using multiple scalp electrodes.

METHODS

Ten healthy age- and gender-matched controls (group 1) and 20 end-stage kidney disease (ESKD) male patients on maintenance hemodialysis with no other comorbidities that affect CF were studied before (group 2) and 3 months after successful transplantation (group 3).

RESULTS

ESKD population had mean age of 29.7 ± 7.5 years, with mean dialysis vintage and post-transplant period being 10.3 ± 6.9 and 3.2 ± 0.4 months, respectively. Mean P300 latencies in groups 1, 2 and 3 were 319 ± 33.6, 348.6 ± 27.8 and 316.4 ± 33.4 ms, respectively (P < 0.001 group 1 vs 2 and group 2 vs 3; group 1 vs 3 NS). Mean P300 amplitude in groups 1, 2 and 3 was 27.9 ± 12.8, 13.4 ± 8.6 and 14.6 ± 9.4 µV, respectively (P < 0.001 group 1 vs 2 and group 1 vs 3; group 2 vs 3 NS). P300 latencies correlated negatively with hemoglobin and serum albumin.

CONCLUSIONS

ESKD patients have impaired CF as documented by prolonged P300 latencies. There was normalization of P300 latencies post-transplantation indicating role of uremic toxins in CF impairment.

Symptom Management of the Patient with CKD: The Role of Dialysis

As kidney disease progresses, patients often experience a variety of symptoms. A challenge for the nephrologist is to help determine if these symptoms are related to advancing CKD or the effect of various comorbidities and/or medications prescribed. The clinician also must decide the timing of dialysis initiation. The initiation of dialysis can have a variable effect on quality of life measures and the alleviation of uremic signs and symptoms, such as anorexia, fatigue, cognitive impairment, depressive symptoms, pruritus, and sleep disturbances. Thus, the initiation of dialysis should be a shared decision-making process among the patient, the family and the nephrology team; information should be provided, in an ongoing dialogue, to patients and their families concerning the benefits, risks, and effect of dialysis therapies on their lives.

Cognitive Testing in Patients with CKD: The Problem of Missing Cases

BACKGROUND AND OBJECTIVES

Cognitive testing is only valid in individuals with sufficient visual and motor skills and motivation to participate. Patients on dialysis usually suffer from limitations, such as impaired vision, motor difficulties, and depression. Hence, it is doubtful that the true value of cognitive functioning can be measured without bias. Consequently, many patients are excluded from cognitive testing. We focused on reasons for exclusion and analyzed characteristics of nontestable patients.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

Within the Choice of Renal Replacement Therapy Project (baseline survey: May 2014 to May 2015), n=767 patients on peritoneal dialysis (n=240) or hemodialysis (n=527) were tested with the Trail Making Test-B and the German d2-Revision Test and completed the Kidney Disease Quality of Life Short Form cognition subscale. We divided the sample into patients with missing cognitive testing data and patients with full cognitive testing data, analyzed reasons for nonfeasibility, and compared subsamples with regard to psychosocial and physical metrics. The exclusion categories were linked to patient characteristics potentially associated with missing data (age, comorbidity, depression, and education level) by calculation of λ-coefficient.

RESULTS

The subsamples consisted of n=366 (48%) patients with missing data (peritoneal dialysis =62, hemodialysis =304) and n=401 patients with full cognitive testing data (peritoneal dialysis =178, hemodialysis =223). Patients were excluded due to visual impairment (49%), lack of motivation (31%), and motor impairment (13%). The remaining 8% did not follow instructions, suffered from medical incidents, or had language difficulties. Compared with patients with full cognitive testing data, they were more likely to have depression; be treated with hemodialysis; be older, nonworking, or more comorbid; and experience poorer shared decision making. Reasons for exclusion were not related to levels of age, comorbidity score, depression score, or education level.

CONCLUSIONS

We excluded almost one half of eligible patients from cognitive testing due to visual, motivational, or motor difficulties. Our findings are consistent with exclusion categories reported from the literature. We should be aware that, because of disease-related limitations, conclusions about cognitive functioning in the CKD population may be biased. In the future, nonvisual and nonverbal cognitive testing can be a valuable resource.

Risk for cognitive impairment across 22 measures of cognitive ability in early-stage chronic kidney disease

Background

Chronic kidney disease (CKD) is a significant risk factor for cognitive impairment. Previous studies have examined differences in cognitive impairment between persons with and without CKD using multiple cognitive outcomes, but few have done this for an extensive battery of cognitive tests. We relate early-stage CKD to two indices of impairment for 22 measures of cognitive ability.

Methods

The study was community-based and cross-sectional with 898 individuals free from dementia and end-stage renal disease. Estimated glomerular filtration rate (eGFR) was calculated using the chronic kidney disease epidemiology collaboration equation and classified as <60 or ≥60 mL/min/1.73 m2, based on consensus definitions of Stage 3 or greater CKD. The eGFR classifications were related to modest [≥1 standard deviation (SD) below the mean] and severe (≥1.5 SD below the mean) impairment on each measure using logistic regression analyses adjusting for potential risk factors.

Results

A total of 146 individuals (16.3%) had eGFR <60 mL/min/1.73 m2 (mean 51.6 ± 10.1 mL/min/1.73 m2). These participants had significantly greater risk for modestly impaired abilities in the scanning and tracking and visual-spatial organization/memory (VSOM) domains after accounting for comorbidity-related risk factors [odds ratios (ORs) between 1.68 and 2.16], as well as greater risk for severely impaired functioning in the language domain (OR = 2.65).

Conclusions

Participants with eGFR <60 mL/min/1.73 m2 were at higher risk for cognitive impairment than those with eGFR ≥60 mL/min/1.73 m2 on the majority of cognitive abilities, specifically those within the VSOM, Language, and scanning and tracking domains. Targeted screening for cognitive deficits in kidney disease patients early in their disease course may be warranted.

Serious Fall Injuries Before and After Initiation of Hemodialysis Among Older ESRD Patients in the United States: A Retrospective Cohort Study

BACKGROUND

Because initiation of dialysis therapy often occurs in the setting of acute illness and may signal worsening health and functional decline, we examined whether rates of serious fall injuries among older hemodialysis patients differ before and after dialysis therapy initiation.

STUDY DESIGN

Retrospective cohort study of claims data from the 2 years spanning dialysis therapy initiation among patients initiating dialysis therapy in 2010 to 2012.

SETTING & PARTICIPANTS

Claims from 81,653 Medicare end-stage renal disease beneficiaries aged 67 to 100 years.

PREDICTOR

Post- versus pre-dialysis therapy initiation periods, defined as on or after versus before dialysis therapy initiation.

OUTCOMES

Serious fall injuries were defined using diagnostic codes for falls in combination with fractures, brain injuries, or joint dislocation. Incidence rate ratios (overall and stratified) for post- versus pre-dialysis therapy initiation periods were estimated using generalized estimating equation models with a negative binomial link.

RESULTS

Overall, 12,757 serious fall injuries occurred in the pre- and post-dialysis therapy initiation periods. Annual rates of serious fall injuries were 64.4 (95% CI, 62.7-66.2) and 107.8 (95% CI, 105.4-110.3) per 1,000 patient-years, respectively, in the pre- and post-dialysis therapy initiation periods (incidence rate ratio, 1.62; 95% CI, 1.56-1.67). Relative rates of serious fall injuries in the post- vs pre-dialysis initiation periods were of greater magnitude among patients who were younger (<75 years), had pre-end-stage renal disease nephrology care, had albumin levels > 3g/dL, were able to walk and transfer, did not need assistance with activities of daily living, and were not institutionalized compared with relative rates among their counterparts.

LIMITATIONS

Potential misclassification due to the use of claims data and survival bias among those initiating hemodialysis therapy.

CONCLUSIONS

Among older Medicare beneficiaries receiving hemodialysis, serious fall injuries are common, the post-dialysis initiation period is a high-risk time for falls, and dialysis therapy initiation may be an important time to screen for fall risk factors and implement multifactorial fall prevention strategies.