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

The alterations of sleep and frontal functions in chronic hemodialysis: Pathogenesis and therapeutic perspectives

Chronic kidney disease (CKD) and, in particular, chronic haemodialysis (HD) patients have a high risk of developing sleep disorders and executive dysfunction. Sleep disorders have a prevalence of 75 % in the haemodialysed population and several causes are behind their occurrence: sympatho-vagal imbalances, low melatonin production, vitamin D deficiency, altered cerebral haemodynamics and haemodialysis-induced vascular stress. Executive dysfunction affects about 55 % of haemodialysis patients. The causes can be ascribed to dysfunctions of the frontal lobes. HD patients show frontal brain atrophy and reduced brain activity and connectivity of several frontal and prefrontal areas. Sleep quality also has a significant impact on executive functions; inefficient and fragmented sleep reduces the efficiency of executive functions and increases the risk of dementia. Sleep deprivation also alters the connectivity and structure of several frontal areas. Thus, sleep and executive functions seem to be closely linked. Multidisciplinary care of patients with CKD and in HD appears essential to structure preventive interventions, pharmacological and non-pharmacological treatments that can improve sleep quality, preserve the integrity of executive functions and improve their quality of life.

Prevalence and risk factors of pre-frailty and frailty in hemodialysis patients in central China

The current study was to explore the prevalence and risk factors elements of pre-frailty and frailty among patients undergoing hemodialysis (HD) in central China. A cross-sectional, multi-institutional investigation was conducted. From March to May 2024, using the convenience sampling method, a total of 408 HD patients from four hospitals in Xiangyang, China, were recruited for this study. The participants' demographics, lifestyle factors, factors related to dialysis treatment, the FRAIL scale, psychological resilience, and medical coping modes were assessed using a questionnaire. Multi-categorical logistic regression was performed to examine factors associated with pre-frailty and frailty in this population. Furthermore, to evaluate the independent relationship between frailty and psychological resilience, multiple regression analysis was used to adjust potential confounders and obtain odds ratios (OR) and 95% confidence intervals (CI). Pearson correlation analysis was used for correlation analysis among various scales. Among the 408 participants, the prevalence of pre-frailty and frailty among participants for all ages was 26.2% and 38.5%. Multivariate logistic regression analysis showed that smoking status, falls, heart disease, and psychological resilience are all associated with pre-frailty and frailty. The Pearson correlation analysis showed that resignation was positively related to frailty and negatively related to psychological resilience in patients. Confrontation and avoidance were positively related to psychological resilience. Frailty was negatively related to psychological resilience. Psychological resilience was independently linearly associated with pre-frailty (OR 0.49, 95% CI 0.32-0.75, p < 0.001) and frailty (OR  0.53, 95% CI 0.35-0.80, p = 0.003). Our findings point to the necessity for active screening prevalence and risk factors for pre-frailty (26.2%) and frailty (38.5%) in adult HD patients of all ages. Pre-frailty and frailty among HD patients are associated with lower psychological resilience and a higher likelihood of using negative coping mechanisms.

Evaluation of effect of cooled haemodialysis on cognition in patients with end-stage kidney disease (ECHECKED) feasibility randomised controlled trial results

BACKGROUND

Cognitive impairment is common in haemodialysis patients with no known beneficial interventions. Cooler dialysate slows brain white-matter changes, but its effect on cognition is unknown. This feasibility trial was performed to inform a fully-powered, randomised trial to assess this.

METHODS

We aimed to randomise (1:1) 90 haemodialysis patients to this double-blinded, randomised controlled feasibility trial to standard care (dialysate-temperature 36.5 °C) or intervention (35 °C). Eligible patients were adult chronic haemodialysis recipients with no established diagnosis of dementia or psychiatric disease. The primary outcome was change in Montreal Cognitive Assessment (MoCA) score at 12-months. Secondary outcomes included recruitment and attrition rates, reasons for non-recruitment, intradialytic hypotension, depression, patient burden, computerised cognition test battery, and quality of life.

FINDINGS

Of 334 patients screened, 160 were eligible. 99 declined mainly for the extra non-dialysis day study visits. Sixty-one patients consented, 43 randomised - 20 in standard care, 23 in intervention arms; 13 withdrew for non-dialysis day visits and 5 without reason before randomisation. 27 patients (12 standard care, 15 intervention) completed the trial - 5 died, 1 transplanted, 4 withdrew consent, and 6 could not attend due to the pandemic. Low temperature dialysis was well tolerated. There was no difference in change in MoCA from baseline to 12 months between the standard and intervention arms; 1.0 (-2.8-3.0, p = 0.755) and - 2.0 (-1.0 - -4.0, p = 0.047) respectively. There were no differences between groups on any secondary measures. There were no significant adverse events reported.

DISCUSSION

The trial was significantly affected by the COVID-19 pandemic contributing to an attrition rate of 27%. The non-dialysis day research visits were mainly responsible for low recruitment and consent withdrawal. There are several learning points, described in the article, which will inform design of definitive trials in this area in the future.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT03645733. Registration date 24/08/2018.

A pictorial neuroradiological review of brain vascular abnormalities in patients with kidney disease

A well-known link exists between cerebrovascular disease and chronic kidney disease. Cerebrovascular pathology in patients with kidney disease may be asymptomatic and occasionally discovered through neuroradiological examinations or it may present with neurological symptoms. Covert cerebrovascular lesions represent the earliest injuries associated with chronic kidney disease and primarily result from small vessel damage. These conditions often manifest incidentally, appearing as structural changes (such as lacunes, white matter lesions, enlarged perivascular spaces, cerebral microbleeds, and atrophy) as well as microstructural and hemodynamic alterations, detectable through routine and advanced functional MRIs. These alterations may be associated with a higher risk of stroke, cognitive decline, and dementia. Patients with end-stage renal disease or chronic kidney disease undergoing dialysis may be at increased risk of large-artery atherosclerosis, cardio-embolism, or small-vessel occlusion, and they may experience symptomatic acute ischemic strokes as rare complications. Currently, there are no established guidelines or standardized diagnostic protocols for preventing cerebrovascular disease in patients with kidney disease. Clinical and radiological studies are warranted to evaluate the usefulness of incorporating neuroimaging into the diagnostic work-up of these patients in order to improve prognosis and reduce diagnostic delays.

Combinatorial lipidomics and proteomics underscore erythrocyte lipid membrane aberrations in the development of adverse cardio-cerebrovascular complications in maintenance hemodialysis patients

Patients on maintenance hemodialysis exhibit a notably higher risk of cardio-cerebrovascular complications that constitute the major cause of death. Preceding studies have reported conflicting associations between traditional lipid measures and clinical outcome in dialysis patients. In this prospective longitudinal study, we utilized quantitative lipidomics to elucidate, at molecular resolution, changes in lipidome profiles of erythrocyte and plasma samples collected from maintenance hemodialysis patients followed up for 86 months (≈7 years). Primary outcome was defined as cardiovascular-related deaths or new-onset cardio-cerebrovascular events. Cox regression model uncovered plasma/erythrocyte lipids associated with incident cardio-cerebrovascular events in the erythrocyte cohort (n = 117 patients, 37 events) and plasma cohort (n = 45 patients, 11 events), respectively. Both the erythrocyte lipid panel [PA 40:5, PI 34:2, PC 42:6, AUC = 0.83] and plasma lipid panel [PC O-34:1, GM3 18:1; O2/25:0, TG 44:1(16:1_28:0), AUC = 0.94] significantly improved the prediction of cardio-cerebrovascular-related outcome compared to the base model comprising age, sex and dialysis vintage alone. Our findings underscore the pathophysiological significance of anionic phospholipid accretion in erythrocytes in the development of cardio-cerebrovascular complications in dialysis patients. In particular, distorted membrane lipid asymmetry leads to compromised membrane deformability, aberrant cell-cell interactions and altered glutathione metabolism in the erythrocytes of high-risk individuals even at relatively early stage of hemodialysis. Our findings thus underscore the importance of maintaining the RBC pool to lower the risk of cardio-cerebrovascular complications in dialysis patients.

Harnessing the eccrine sweat glands for the management of interdialytic weight gain - a pilot study

Hemodialysis patients are susceptible to excess volume accumulation, particularly over the 2-day interval (long interdialytic gap), resulting in higher interdialytic weight gain (IDWG). We thought to determine whether a novel device designed to enhance fluid and salt loss by activating the eccrine sweat glands can mitigate IDWG. Patients eligible for the study were undergoing regular hemodialysis for ≥3 months, without residual renal function, and with IDWG (as a percentage of IDWG/dry body weight) ≥2.5%. Treatments were administered at the patient's home. The primary performance endpoint was differences in weight gain over long interdialytic period with the device compared to the control period. Secondary exploratory endpoints included the need for ultrafiltration (UF) rate > 10 mL/kg/h in the post-interval dialysis. Five patients were enrolled into the pilot study (age range 26 to 69 years, 3 women). The hourly mean weight loss from sweat was 186 ± 45 g/h. The average procedure length was 4.5 h with an average fluid loss of 899 ± 283 grams per procedure. The average least-squares mean absolute difference of IDWG between the control and treatment periods was -2.0%; (95% confidence interval [CI], -2.9% to -1.2%, p < 0001). The reduction in IDWG was associated a reduction in UF rates, from 9.23 ± 3.7 mL/kg/h to 5.55 ± 2.45 mL/kg/h between the control and treatment periods (p < 0.001), resulting in a safe UF rate (<10 mL/kg/h) in all post-treatment sessions. We conclude that enhancing sweat rate can mitigate IDWG in hemodialysis patients.

Gait abnormalities and longitudinal fall risk in older patients with end-stage kidney disease and sarcopenia

BACKGROUND

Sarcopenia, gait disturbance, and intradialytic hypotension are among the various factors that contribute to fall risk. This study aimed to investigate the relationship between risk of sarcopenia, hemodialysis (HD) session, and long-term fall risk in older end-stage kidney disease (ESKD) patients by analyzing their spatiotemporal gait characteristics.

METHODS

We recruited 22 non-demented patients aged ≥ 65 years who were undergoing maintenance HD. Participants were divided into two groups based on their SARC-F score (< 4 and ≥ 4) to identify those with higher and lower risk of sarcopenia. Demographics, comorbidities, and renal parameters were compared between groups. Inertial measurement unit-based technology equipped with triaxial accelerometry and gyroscope was used to evaluate gait characteristics. The gait task was assessed both before and after dialysis using the Timed-Up and Go (TUG) test and a 10-meter walking test at a regular pace. Essential gait parameters were thoroughly analyzed, including gait speed, stride time, stride length, double-support phase, stability, and symmetry. We investigated the interaction between the dialysis procedure and gait components. Outcome of interest was any occurrence of injurious fall during follow-up period. Logistic regression models were employed to examine the relationship between baseline gait markers and long-term fall risk.

RESULTS

The SARC-F ≥ 4 group showed various gait abnormalities, including longer TUG time, slower gait speed, longer stride time, shorter stride length, and longer double support time compared to counterpart (SARC-F < 4). After HD sessions, the SARC-F ≥ 4 group showed a 2.0-second decrease in TUG task time, an 8.0 cm/s increase in gait speed, an 11.6% lower stride time, and a 2.4% increase in gait symmetry with significant group-time interactions. Shorter stride length and longer double support time were associated with injurious falls during the two-year follow-up.

CONCLUSION

Our study demonstrated the utility of triaxial accelerometers in extracting gait characteristics in older HD patients. High-risk sarcopenia (SARC-F ≥ 4) was associated with various gait abnormalities, some of which partially improved after HD sessions. These gait abnormalities were predictive of future falls, highlighting their prognostic significance.

Associations of Cognitive Function with Serum Magnesium and Phosphate in Hemodialysis Patients: A Cross-Sectional Analysis of the Osaka Dialysis Complication Study (ODCS)

Cognitive impairment and dementia are common in patients with chronic kidney disease, including those undergoing hemodialysis. Since magnesium and phosphate play important roles in brain function and aging, alterations in these and other factors related to bone mineral disorder (MBD) may contribute to low cognitive performance in patients on hemodialysis. This cross-sectional study examined the associations between cognitive function and MBD-related factors among 1207 patients on maintenance hemodialysis. Cognitive function was assessed by the Modified Mini-Mental State examination (3MS). The exposure variables of interest were serum magnesium, phosphate, calcium, calcium-phosphate product, intact parathyroid hormone, fetuin-A, T50 calciprotein crystallization test, use of phosphate binders, use of cinacalcet, and use of vitamin D receptor activators. Multivariable-adjusted linear regression models were used to examine the associations between 3MS and each of the exposure variables independent of 13 potential non-mineral confounders. We found that lower 3MS was associated with lower serum magnesium, lower phosphate, lower calcium-phosphate product, and nonuse of phosphate binders. These results suggest that magnesium and phosphate play potentially protective roles against cognitive impairment in this population.

Addressing cognitive impairment in peritoneal dialysis: a systematic review and meta-analysis of prevalence, risk factors, and outcomes

Background

Cognitive impairment (CI) is a critical complication in peritoneal dialysis (PD) patients, associated with decreased quality of life and increased hospitalization. Despite its significant impact, the prevalence, risk factors, and consequences of CI in PD patients are not well understood. We aimed to determine the prevalence, risk factors, and outcomes of CI in PD patients.

Methods

We performed systematic reviews in OVID Medline, Embase, and Cochrane databases until February 2024 to identify cross-sectional and cohort studies on prevalence of CI (identified by cognitive assessment scales) in PD patients. The Newcastle-Ottawa Scale was used to assess risk of bias. A pooled meta-analysis of CI prevalence in PD and a subgroup analysis comparing the risk of CI between PD and non-PD settings were performed using a random-effects model.

Results

A total of 19 studies were identified, involving 2882 PD patients. The pooled prevalence of CI in PD patients was 47.7% (95%CI: 35.8-59.9%). CI in patients undergoing PD appears to be associated with older age, female gender, lower levels of education, and is linked to higher rates of hospitalization and peritonitis, compared to those without CI. However, it is not associated with increased mortality. Compared to hemodialysis, PD showed a trend toward a lower risk of CI (OR 0.64, 95%CI 0.39-1.03; P = .068).

Conclusion

CI is highly prevalent and associated with several adverse clinical outcomes in PD patients. These findings could contribute to facilitate the development of screening and early intervention strategies to reduce the burden of disease in this population.

Social Support and Quality of Life in Hemodialysis Patients: A Comparative Study with Healthy Controls

Background and Objectives: Hemodialysis patients face significant physical and psychological challenges, including diminished quality of life and reduced social support. This study aimed to assess the levels of social support and quality of life in hemodialysis patients and identify the sociodemographic and dialysis-related factors influencing these outcomes. Materials and Methods: This study included 115 hemodialysis patients and 107 healthy controls. Social support was measured using the Modified Social Support Survey (MSSS) and its abbreviated version (MSSS-5). Quality of life was assessed using the WHOQOL-BREF questionnaire. Demographic variables (age, sex, education, marital status) and dialysis-related factors (session duration, Kt/V, vascular access type, and urea reduction ratio) were analyzed to determine their effects on social support and quality of life. Results: Hemodialysis patients reported significantly lower scores in the Physical Health and Psychological Health domains of the WHOQOL-BREF compared to healthy controls. Males on hemodialysis scored lower than the controls in the Physical Health, Psychological Health, and Environment domains of the WHOQOL-BREF and the Affectionate Support and Positive Social Interaction subscales of MSSS. Conversely, hemodialysis females reported higher scores for Tangible Support, Emotional/Informational Support, and Affectionate Support. Longer dialysis sessions negatively impacted the Social Relationships domain. Married hemodialysis patients had higher Emotional/Informational Support and Affectionate Support scores. Conclusions: Hemodialysis patients experience diminished physical and psychological quality of life, particularly males. Social support, especially emotional and informational support, is crucial for hemodialysis patients, with marital status playing a key role. Addressing these psychosocial factors may improve outcomes for hemodialysis patients.

Reduced functional connectivity induced by longitudinal alterations of structure and perfusion may be associated with cognitive impairment in patients on maintenance hemodialysis

Hemodialysis (HD) leads to cognitive impairment; however, the pathophysiology of maintenance HD remains unclear. This study aimed to investigate the longitudinal alterations in gray matter volume (GMV) and cerebral blood flow (CBF) in patients on HD at follow-up compared with baseline, examine the alterations in functional connectivity (FC) by defining co-changed brain regions as seed points, and investigate the correlation between the co-changed brain regions and neuropsychological test scores. Twenty-seven patients with HD and 30 healthy controls were enrolled in this study. All participants underwent high-resolution T1-weighted imaging, arterial spin labeling, and functional MR imaging to measure GMV, CBF, and FC. The patients on HD were assessed at baseline and 3 years subsequently. The right and left medial superior frontal gyrus (SFGmed.L) exhibited significantly lower GMV and CBF in patients on HD at follow-up compared with baseline and lower FC between the SFGmed.L and left middle temporal gyrus (MTG.L). FC between the SFGmed.L and MTG.L was positively correlated with neuropsychological test scores in the HD group at follow-up. Reduced GMV and CBF may result in decreased FC between the SFGmed.L and MTG.L, which may be associated with cognitive impairment in patients on maintenance HD. Our findings provide unique insights into the pathological mechanisms of patients on maintenance HD with cognitive impairment.

Association between cerebral blood flow variation and cognitive decline in older patients undergoing hemodialysis

Background

The mechanism of cognitive impairment in hemodialysis patients is multifactorial. The relationship between cerebral blood flow and the decline of cognitive function is poorly understood.

Objective

To investigate the association between cerebral blood flow variation and decline of cognitive function in older patients undergoing hemodialysis.

Methods

In this prospective observational cohort study of 121 older patients undergoing hemodialysis, we used transcranial Doppler ultrasound (TCD) to measure cerebral arterial mean flow velocity (MFV) throughout dialysis, assessed cognitive function at baseline and 12-month follow-up, and then analyzed associations between MFV and changes on cognitive scores.

Results

TCD recordings demonstrated a significant reduction in MFV throughout dialysis, which were significantly correlated with cumulative ultrafiltration volume (rho 0.356, p < 0.001), ΔSBP (rho 0.251, p = 0.005), and ΔMAP (rho 0.194, p = 0.032). Compared with the baseline assessments, cognitive scores of participants at the 12-month follow-up were significantly worsened in global cognition (MOCA), some tests of memory (CFT-memory), executive function (TMT-B, SCWT-C, and SCWT-T), attention/processing speed (SDMT), and visuospatial function (CFT-copy) (p < 0.05). The worsening scores in global cognition (MOCA) (β = 0.066, 95% CI 0.018-0.113, p = 0.007) and some tests of memory (AVLT5) (β = 0.050, 95% CI 0.004-0.097, p = 0.035) and executive function (TMT-B, SCWT-C, SCWT-T) (β = 1.955, 95% CI 0.457-3.453, p = 0.011; β = 0.298, 95% CI 0.112-0.484, p = 0.002 and β = 1.371, 95% CI 0.429-2.303, p = 0.004, respectively) were significantly associated with the reduction of MFV.

Conclusion

Hemodialysis may significantly reduce cerebral blood flow in older patients; Repetitive intradialytic decreases in CBF may be one of the mechanisms underlying the decline of cognitive function.

Clinical trial registration

https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S000C5B5&selectaction=Edit&uid=U0003QEL&ts=4&cx=-djoi2.

Negative association of serum neurofilament light chain with estimated glomerular filtration rate levels and the impact of gender

Background

The relationship between kidney function and brain function is complex and poorly understood. This study aims to investigate the association between serum neurofilament light chain (sNfL) and levels of estimated glomerular filtration rate (eGFR), offering new insights into their interactions.

Methods

Data from the national health and nutrition examination survey (NHANES) in 2013-2014, linked with national death index records, were used. Participants who met specific criteria were analyzed. Baseline characteristics were stratified by tertiles of sNfL levels and compared using weighted Kruskal-Wallis and chi-square tests. Weighted linear regression models, both unadjusted and adjusted, evaluated the relationship between log sNfL and eGFR. Subgroup and interaction analyses validated the findings. Restricted cubic spline, scatter plots, and Spearman correlation confirmed the relationship between log sNfL and eGFR.

Results

A total of 2,038 eligible participants were included. Higher sNfL levels were significantly associated with lower eGFR (p < 0.01). The highest sNfL tertile had a significantly higher mortality rate (p < 0.01). Fully adjusted multivariable weighted linear regression showed a significant negative correlation between log sNfL and eGFR (per 10-unit increase; β = -0.07, 95% CI: -0.10 to -0.04, p < 0.01). Subgroup analyses consistently supported this negative correlation (p < 0.01). Interaction analysis revealed a significant gender difference (p = 0.032), with males showing a - 0.06 (-0.09, -0.04) decrease and females a - 0.07 (-0.11, -0.04) decrease in log sNfL per 10-unit increase in eGFR. Restricted cubic spline confirmed a linear relationship (p-non-linear = 0.121), and the Spearman correlation coefficient was -0.45. Females had slightly lower log sNfL levels compared to males at equivalent eGFR levels.

Conclusion

A significant negative correlation was found between log sNfL and eGFR levels. Gender influenced the degree of this negative association. Further research is needed to validate these findings and elucidate their underlying mechanisms.

Association between TMSE/MoCA and MIS/NAF in ESKD patients undergoing hemodialysis: a cross-sectional study

BACKGROUND

Both cognitive impairment and malnutrition are common in hemodialysis (HD) patients and are associated with increased hospitalization rates, infection, poor clinical outcomes, and mortality. The study investigated the association between cognitive and nutrition status among end-stage kidney disease (ESKD) patients undergoing hemodialysis.

METHODS

In this cross-sectional study, we enrolled 115 patients with ESKD who underwent regular hemodialysis (HD). Data collection included the use of screening tools for mild cognitive impairment (MCI), specifically Thai Mental State Examination (TMSE) and Montreal Cognitive Assessment (MoCA). In addition, we collected data using nutritional screening tools including Malnutrition Inflammation Score (MIS) and Nutrition Alert Form (NAF). Our primary outcome was to demonstrate whether there was a relationship between TMSE/MoCA and MIS/NAF scores in this population. Secondary outcomes were a prevalence of MCI and malnutrition status in ESKD patients, an association between TMSE and MoCA with other surrogate nutritional markers, and factors affecting MCI in such patients.

RESULTS

A total of 109 patients undergoing HD completed our protocol. Their mean age was 63.42 (± 15.82) years, and 51.38% were male. Mean TMSE and MoCA were 23.98 (± 5.06) points and 18.3 (± 6.40) points, respectively. The prevalence of TMSE ≤ 23 and MoCA ≤ 24 were 39.45% and 83.49%, respectively. TMSE had a statistically significant negative correlation with MIS (R2 = 0.16, p < 0.001) and NAF. MoCA also negatively correlated with MIS and NAF. The age, total educational year, the status of whether having a caregiver, serum albumin, serum phosphorus level, handgrip strength, and lean mass tissue were correlated with TMSE.

CONCLUSION

Nutritional parameters, including MIS score, NAF score, serum albumin, lean tissue mass, and lean tissue index, significantly correlate with TMSE and MoCA.

Cognitive profile of kidney transplant patients and impact of deceased vs. living donor transplantation

BACKGROUND

It is important to learn more about the prevalence, severity and characteristics (i.e., which cognitive abilities are especially affected) of cognitive impairment in kidney transplant patients. Furthermore, the impact of living vs. deceased donor renal transplantation on cognitive outcome in this patient group needs further studies.

METHODS

Fifty-nine patients (43 men, age 55 ± 13 years) who received a deceased donor or living donor kidney transplant, completed a comprehensive neuropsychological test assessment. Neuropsychological tests explored the cognitive domains of verbal and visual memory, attention, and executive functions.

RESULTS

Fifteen percent  of the patients had mild, 25% moderate, and 15% severe cognitive impairment. The level of domain-specific cognitive deficit differed between verbal memory, attention, and executive functions (χ2(2) = 7.11, p = 0.029). On average, patients showed the highest deficit in executive functions, and the lowest deficit in verbal memory. Patients who received a kidney graft from a deceased donor were more likely to have a cognitive impairment than those who received a kidney graft from a living donor (OR = 3.03, 95% CI [0.99,9.32], Wald χ2(1) = 3.74, p = 0.053). This effect was independent of time on dialysis as well as of creatinine levels, or creatinine clearance.

CONCLUSIONS

Our results show that in kidney transplant patients with cognitive impairment, the cognitive domain of executive functions is the most affected one. This might be detrimental for quality of life. The fact that patients who received living donor kidneys seem to do better in terms of cognition than patients with deceased donor kidneys deserves more attention in future research.

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).

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.

Research Progress on Cognitive Frailty in Older Adults with Chronic Kidney Disease

BACKGROUND

As the medical challenges posed by the ageing population become increasingly severe, the proportion of older people among patients with chronic kidney disease (CKD) is increasing every year.

SUMMARY

The prevalence of frailty in patients with CKD is significantly higher than that in the general population, and older patients are also a high-risk group for frailty and cognitive impairment. Cognitive frailty, as an important subtype of frailty, is a syndrome characterised by cognitive dysfunction caused by physiological factors, excluding Alzheimer's disease and other types of dementia. It is characterised by the coexistence of physical frailty and cognitive impairment. Previous studies have mainly focused on cognitive impairment, and there is limited research on cognitive frailty, particularly in older patients with CKD.

KEY MESSAGES

This article provides a comprehensive review of the concept, epidemiology, screening methods, prevention, and treatment measures and possible pathogenesis of cognitive frailty in patients with CKD.

The covariant structural and functional neuro-correlates of cognitive impairments in patients with end-stage renal diseases

Introduction

Cognitive impairment (CI) is a common complication of end-stage renal disease (ESRD) that is associated with structural and functional changes in the brain. However, whether a joint structural and functional alteration pattern exists that is related to CI in ESRD is unclear.

Methods

In this study, instead of looking at brain structure and function separately, we aim to investigate the covariant characteristics of both functional and structural aspects. Specifically, we took the fusion analysis approach, namely, multimodal canonical correlation analysis and joint independent component analysis (mCCA+jICA), to jointly study the discriminative features in gray matter volume (GMV) measured by T1-weighted (T1w) MRI, fractional anisotropy (FA) in white matter measured by diffusion MRI, and the amplitude of low-frequency fluctuation (ALFF) measured by blood oxygenation-level-dependent (BOLD) MRI in 78 ESRD patients versus 64 healthy controls (HCs), followed by a mediation effect analysis to explore the relationship between neuroimaging findings, cognitive impairments and uremic toxins.

Results

Two joint group-discriminative independent components (ICs) were found to show covariant abnormalities across FA, GMV, and ALFF (all p < 0.05). The most dominant joint IC revealed associative patterns of alterations of GMV (in the precentral gyrus, occipital lobe, temporal lobe, parahippocampal gyrus, and hippocampus), alterations of ALFF (in the precuneus, superior parietal gyrus, and superior occipital gyrus), and of white matter FA (in the corticospinal tract and inferior frontal occipital fasciculus). Another significant IC revealed associative alterations of GMV (in the dorsolateral prefrontal and orbitofrontal cortex) and FA (in the forceps minor). Moreover, the brain changes identified by FA and GMV in the above-mentioned brain regions were found to mediate the negative correlation between serum phosphate and mini-mental state examination (MMSE) scores (all p < 0.05).

Conclusion

The mCCA+jICA method was demonstrated to be capable of revealing covariant abnormalities across neuronal features of different types in ESRD patients as contrasted to HCs, and joint brain changes may play an important role in mediating the relationship between serum toxins and CIs in ESRD. Our results show the mCCA+jICA fusion analysis approach may provide new insights into similar neurobiological studies.

Longitudinal changes in diffusion tensor imaging in hemodialysis patients

INTRODUCTION

Hemodialysis patients have increased white matter and gray matter pathology in the brain relative to controls based on MRI. Diffusion tensor imaging is useful in detecting differences between hemodialysis and controls but has not identified the expected longitudinal decline in hemodialysis patients. In this study we implemented specialized post-processing techniques to reduce noise to detect longitudinal changes in diffusion tensor imaging parameters and evaluated for any association with changes in cognition.

METHODS

We collected anatomical and diffusion MRIs as well as cognitive testing from in-center hemodialysis patients at baseline and 1 year later. Gray matter thickness, white matter volume, and white matter diffusion tensor imaging parameters were measured to identify longitudinal changes. We analyzed the diffusion tensor imaging parameters by averaging the whole white matter and using a pothole analysis. Eighteen hemodialysis patients were included in the longitudinal analysis and 15 controls were used for the pothole analysis. We used the NIH Toolbox Cognition Battery to assess cognitive performance over the same time frame.

FINDINGS

Over the course of a year on hemodialysis, we found a decrease in white matter fractional anisotropy across the entire white matter (p < 0.01), and an increase in the number of white matter fractional anisotropy voxels below pothole threshold (p = 0.03). We did not find any relationship between changes in whole brain structural parameters and cognitive performance.

DISCUSSION

By employing noise reducing techniques, we were able to detect longitudinal changes in diffusion tensor imaging parameters in hemodialysis patients. The fractional anisotropy declines over the year indicate significant decreases in white matter health. However, we did not find that declines in fractional anisotropy was associated with declines in cognitive performance.

The moderating role of social support in the relationship between death anxiety and resilience among dialysis patients

BACKGROUND

Chronic Kidney Disease (CKD) who receive social support can cope with the challenges. Therefore, this study determined the moderating role of social support in the relationship between death anxiety and resilience among dialysis patients in Qazvin City.

METHODS

This cross-sectional study used a descriptive-analytical approach on 347 dialysis patients in Qazvin City. The data collection tools included several questionnaires. The convenience sampling method was employed. The data were analyzed using SPSS software version 22 and mplus software version 7.2, employing descriptive statistics, such as mean and standard deviation for continuous variables and using counts and percentages for categorical/nominal variables. Regression analysis and tests were used to examine the relationships between variables. Structural Equation Modeling (SEM) analysis was employed to determine direct and indirect relationships between independent and dependent variables.

RESULTS

The prevalence of death anxiety was high (48.3%) among the patients. The mean resilience score was 62.59 ± 15.69, and the mean social support score was 52.23 ± 10.21. There was a significant association between resilience and social support (P < 0.001), as well as between resilience and death anxiety (P < 0.001). Furthermore, a significant relationship was observed between social support and death anxiety (p = 0.015). In the analysis of SEM, both the direct and indirect relationships between resilience and death anxiety were significant through the mediating variable of social support.

CONCLUSION

This study demonstrates that there is a relationship between death anxiety and resilience, and social support significantly moderates the relationship between death anxiety and resilience.

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.

Randomized trial comparing standard versus thermocontrolled haemodialysis using intradialytic cardiac, brain and renal magnetic resonance imaging

BACKGROUND

Ischaemic end-organ damage during haemodialysis (HD) is a significant problem that may be ameliorated by intradialytic cooling. A randomised trial was performed to compare standard HD (SHD; dialysate temperature 37°C) and programmed cooling of the dialysate [thermocontrolled HD (TCHD)] using multiparametric magnetic resonance imaging (MRI) to assess structural, functional and blood flow changes in the heart, brain and kidneys.

METHODS

Prevalent HD patients were randomly allocated to receive either SHD or TCHD for 2 weeks before undergoing serial MRI at four time points: pre-, during (30 min and 180 min) and post-dialysis. MRI measures include cardiac index, myocardial strain, longitudinal relaxation time (T1), myocardial perfusion, internal carotid and basilar artery flow, grey matter perfusion and total kidney volume. Participants then crossed to the other modality to repeat the study protocol.

RESULTS

Eleven participants completed the study. Separation in blood temperature between TCHD (-0.1 ± 0.3°C) and SHD (+0.3 ± 0.2°C; P = .022) was observed, although there was no difference in tympanic temperature changes between arms. There were significant intradialytic reductions in cardiac index, cardiac contractility (left ventricular strain), left carotid and basilar artery blood flow velocities, total kidney volume, longitudinal relaxation time (T1) of the renal cortex and transverse relaxation rate (T2*) of the renal cortex and medulla, but no differences between arms. Pre-dialysis T1 of the myocardium and left ventricular wall mass index were lower after 2 weeks of TCHD compared with SHD [1266 ms (interquartile range 1250-1291) versus 1311 ± 58 ms, P = .02; 66 ± 22 g/m2 versus 72 ± 23 g/m2, P = .004].

CONCLUSIONS

HD adversely affects cardiac function, reduces carotid and basilar artery blood flow and total kidney volume, but mild dialysate cooling using a biofeedback module did not result in differences in intradialytic MRI measures compared with SHD.

Association between white matter hyperintensities and altered cerebral blood flow in maintenance hemodialysis patients: a longitudinal study

OBJECTIVES

To explore changes in cerebral blood flow (CBF) and white matter in hemodialysis patients.

METHODS

Thirty-three hemodialysis patients who underwent two brain MRI at an interval of three years and 33 age- and sex-matched healthy controls (HC) underwent structural and arterial spin-labeling MRI examinations. Intergroup differences in CBF in the gray matter, white matter, and whole matter, and regional white matter hyperintensities (WMH) were analyzed. Based on the changes in CBF between the baseline and follow-up groups, the hemodialysis patients were divided into two subgroups: an increased CBF group and a decreased CBF group. Differences in CBF and WMH between the subgroups and HC were analyzed.

RESULTS

Patients undergoing hemodialysis exhibited increased cerebral watershed (CW) WMH, deep WMH, and periventricular WMH (P < 0.01). The CBF of patients with decreased CBF was higher than that of HC at baseline (,P < 0.01) and lower than that of HC at follow-up (P < 0.01). Compared with the increased CBF group, obvious development of deep WMH was found in the decreased CBF group for the gray matter, white matter, and whole matter (P < 0.01).

CONCLUSIONS

WMH in hemodialysis patients were distributed in the deep white matter, periventricular white matter and CW, and progressed with the extension of hemodialysis duration. CBF in hemodialysis patients could manifest as both increased and decreased, and WMH in patients with decreased CBF developed severely with prolongation of hemodialysis duration.

ADVANCES IN KNOWLEDGE

These findings provide a basis for exploring neuropathological changes of hemodialysis patients.

What is the role of the neutrophil extracellular traps in the cardiovascular disease burden associated with hemodialysis bioincompatibility?

Despite significant progress in dialysis modalities, intermittent renal replacement therapy remains an "unphysiological" treatment that imperfectly corrects uremic disorders and may lead to low-grade chronic inflammation, neutrophil activation, and oxidative stress due to repetitive blood/membrane interactions contributing to the "remaining uremic syndrome" and cardiovascular disease burden of hemodialysis patients. Understanding dialysis bioincompatibility pathways still remains a clinical and biochemical challenge. Indeed, surrogate biomarkers of inflammation including C-reactive protein could not discriminate between all components involved in these complex pathways. A few examples may serve to illustrate the case. Cytokine release during dialysis sessions may be underestimated due to their removal using high-flux dialysis or hemodiafiltration modalities. Complement activation is recognized as a key event of bioincompatibility. However, it appears as an early and transient event with anaphylatoxin level normalization at the end of the dialysis session. Complement activation is generally assumed to trigger leukocyte stimulation leading to proinflammatory mediators' secretion and oxidative burst. In addition to being part of the innate immune response involved in eliminating physically and enzymatically microbes, the formation of Neutrophil Extracellular Traps (NETs), known as NETosis, has been recently identified as a major harmful component in a wide range of pathologies associated with inflammatory processes. NETs result from the neutrophil degranulation induced by reactive oxygen species overproduction via NADPH oxidase and consist of modified chromatin decorated with serine proteases, elastase, bactericidal proteins, and myeloperoxidase (MPO) that produces hypochlorite anion. Currently, NETosis remains poorly investigated as a sensitive and integrated marker of bioincompatibility in dialysis. Only scarce data could be found in the literature. Oxidative burst and NADPH oxidase activation are well-known events in the bioincompatibility phenomenon. NET byproducts such as elastase, MPO, and circulating DNA have been reported to be increased in dialysis patients more specifically during dialysis sessions, and were identified as predictors of poor outcomes. As NETs and MPO could be taken up by endothelium, NETs could be considered as a vascular memory of intermittent bioincompatibility phenomenon. In this working hypothesis article, we summarized the puzzle pieces showing the involvement of NET formation during hemodialysis and postulated that NETosis may act as a disease modifier and may contribute to the comorbid burden associated with dialysis bioincompatibility.

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.

Lean-to-fat tissue ratio as a risk factor for cognitive impairment in patients undergoing maintenance hemodialysis

OBJECTIVE

The relationship between body mass index (BMI) and cognitive impairment (CI) remains controversial, and no research has been done to explore the effect of lean-to-fat (L/F) tissue ratio on the risk of CI in patients undergoing maintenance hemodialysis (MHD) so far. This study aimed to explore the effect of L/F tissue ratio on the risk of incident CI in patients undergoing MHD.

METHODS

In this observational cohort study, 3356 patients were recruited and followed up for a median of 2 years. Global cognitive function was measured using Mini-Mental State Examination score. Lean tissue mass (LTM) and fat tissue mass (FTM) were analyzed using body composition monitor based on bioimpedance spectroscopy (BCM-BIS), and L/F tissue ratio was calculated by LTM divided by FTM. Hazard ratios (HRs) for incident CI were determined by Cox regression.

RESULTS

The median age of the cohort was 55 years, and 68.7% patients were less educated. During the follow-up period, 1249 patients (37.2%) experienced incident CI. Patients with lower L/F tissue ratios had significantly higher risks of CI (HR 1.51, 95% confidence interval 1.24-1.84; p < 0.001) than those with higher L/F tissue ratios. The association between L/F tissue ratio and incident CI persisted in all subgroups stratified by sex, age, education status, especially in older and less educated participants. Both in all our patients and subgroups, BMI and CI occurrence were not independently relevant.

CONCLUSION

The L/F tissue ratio rather than BMI was an independent risk factor of incident cognitive impairment in patients undergoing MHD.

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.

Low intracellular water and incident cognitive impairment in chronic hemodialysis patients

OBJECTIVE

To explore the effect of intracellular water (ICW) evaluated by the bioelectrical Impedance Spectroscopy (BIS) on the risk of incident cognitive impairment (CI) in chronic hemodialysis (HD) patients.

METHODS

Three thousand three hundred eighty-five patients were recruited and monitored prospectively for up to 3 years (the median follow-up time, 2 years) in this observational cohort study. Mini-Mental State Examination score (MMSE) was used to assess the global cognitive function. ICW was measured by body composition monitor based on BIS. Multiple Cox regression models, stratified analyses, and interactive analyses were conducted.

RESULTS

During the follow-up period, 1256 patients (37.1%) experienced incident CI. The incidence of CI was increased with decreasing quartiles of ICW (27.4%, 32.2%, 38.9%, and 50.1% for the fourth, third, second, and first quartiles, respectively). Decreased ICW was significantly associated with incident CI. The association remained statistically significant even after adjusting for age, sex, education, albumin, C-reactive protein, residual renal function and various medical histories. The hazard ratios were 1.38 (1.17-1.64) and 1.28 (1.08-1.52) for ICW quartile 1 and quartile 2, respectively (reference, quartile 4). The association stably existed across subgroups, and the residual renal function had an interactive role in the association between ICW and incident CI (p = 0.014).

CONCLUSION

Low baseline ICW was an independent risk factor for CI in chronic HD patients. Our finding highlights the necessity of using BIS to measure body composition when assessing the risk of CI in HD patients.

Peritoneal dialysis in the setting of acute brain injury: an underappreciated modality

INTRODUCTION

Dialysis is complicated in the setting of acute brain injury (ABI) due to several factors including acute solute shifts, acid base changes, need for anticoagulation, and changes in intracranial pressure. For these reasons, continuous renal replacement therapy (CRRT) is often the chosen modality for renal replacement needs in these patients. Peritoneal dialysis (PD) is less discussed but shares many of the benefits often attributed to CRRT. We describe, from both nephrology and neurosurgical perspectives, a case successfully managed with PD.

CASE

A 25-year-old male with history of end-stage kidney disease (ESKD) secondary to focal segmental glomerulosclerosis on continuous cycling PD for 5 years presented to the hospital with headache and altered mental status. Initial imaging revealed a large intraventricular hemorrhage extending to the fourth ventricle. He underwent an emergent right depressive hemicraniectomy and clot evacuation. Post-operative imaging revealed worsening cerebral edema, intraventricular hemorrhage, and hydrocephalus. The decision was made to continue PD, noting that it retains many of the benefits of CRRT (which it is in fact, a form of) which he tolerated well until the need for a percutaneous gastrostomy tube arose. He was transiently transitioned to hemodialysis but returned to PD once his gastrostomy healed. He continued PD for 1 year without complication and eventually received a kidney transplant.

DISCUSSION

In managing patients with ABI undergoing dialysis, a number of considerations must be undertaken including avoidance of hypotension to maintain cerebral perfusion pressure and minimize ischemia reperfusion injury, avoidance of anticoagulants that can precipitate or worsen bleeding, the potential for cerebral edema due to rapid solute clearance and osmotic dissipation of therapeutic hypernatremia, and the mitigation of intracellular acidosis from bicarbonate delivery. Although underutilized, PD may potentially serve as a viable option for dialysis in the setting of ABI as demonstrated by the case presented.

Characterization of diffusion MRI using the mean apparent propagator model in hemodialysis patients: A pilot study

To better understand documented cognitive decline in hemodialysis (HD) patients, diffusion MRI (dMRI) has been used to characterize brain anatomical deficits relative to controls. Studies to this point have primarily used diffusion tensor imaging (DTI) to model the three-dimensional diffusion of water in HD patients, with DTI parameters reflecting underlying microstructural changes of brain tissue. Since DTI has some limitations in characterizing tissue microstructure, some of which may be complicated by HD, we explored the use of the mean apparent propagator (MAP) model to describe diffusion in HD patients. We collected anatomical T1 and T2 FLAIR MRIs as well as multi-shell dMRI in ten HD participants and ten age-matched controls. The T1 and T2 FLAIR MRIs were used for tissue segmentation and identification of white matter hyperintensity, respectively. Multi-shell dMRI data were used to estimate MAP and DTI diffusion models. Each model was then used to characterize the differences between the HD cohort and the age-matched controls in normal appearing white matter, subcortical gray matter, corpus callosum (CC) and bilateral radiata (Rad). As expected, parameters of both DTI and MAP models of dMRI were significantly different in HD participants compared to controls. However, some MAP parameters suggested additional tissue microstructural changes in HD participants, such as increased axonal diameter. Measurements of non-Gaussianity indicated that MAP provided better a diffusion estimate than DTI, and MAP appeared to provide a more accurate measure of anisotropy in Rad, based on measures of the Rad/CC ratio. In conclusion, parameters of the MAP and DTI models were both sensitive to changes in diffusivity in HD participants compared to controls; however, the MAP model appeared to provide additional detailed information about changes in brain tissue microstructure.

Cognitive disorders in patients with chronic kidney disease: Approaches to prevention and treatment

BACKGROUND

Cognitive impairment is common in patients with chronic kidney disease (CKD), and early intervention may prevent the progression of this condition.

METHODS

Here, we review interventions for the complications of CKD (anemia, secondary hyperparathyroidism, metabolic acidosis, harmful effects of dialysis, the accumulation of uremic toxins) and for prevention of vascular events, interventions that may potentially be protective against cognitive impairment. Furthermore, we discuss nonpharmacological and pharmacological methods to prevent cognitive impairment and/or minimize the latter's impact on CKD patients' daily lives.

RESULTS

A particular attention on kidney function assessment is suggested during work-up for cognitive impairment. Different approaches are promising to reduce cognitive burden in patients with CKD but the availabe dedicated data are scarce.

CONCLUSIONS

There is a need for studies assessing the effect of interventions on the cognitive function of patients with CKD.

Changes in Cerebral Blood Flow in Patients Who Receive Different Durations of Hemodialysis: An Arterial Spin Labeling MRI Study

BACKGROUND AND PURPOSE

This study aimed to determine the changes in cerebral blood flow (CBF) in patients who received different durations of hemodialysis (HD) using arterial spin labeling magnetic resonance imaging.

METHODS

The study included 46 patients who received HD and 24 demographically similar healthy controls (HCs). Patients who received HD were divided into three subgroups based on its duration: HD-1 (n=15, dialysis duration ≤24 months), HD-2 (n=16, dialysis duration >24 and ≤72 months), and HD-3 (n=15, dialysis duration ≥73 months). All subjects completed the Mini Mental State Examination and Montreal Cognitive Assessment tests, and the patients who received HD underwent laboratory tests. Group-level differences in the global and regional CBFs between patients who received HD and HCs were assessed. Correlation analysis was performed to evaluate the associations among CBF, clinical variables, and cognitive function.

RESULTS

Compared with HCs, global and regional CBFs were significantly increased in the HD-1 and HD-2 groups (p<0.05), but there was no significant difference in the HD-3 group (p>0.05). However, compared with the HD-1 group, the HD-3 group had significantly decreased global and regional CBFs (p<0.05). The cognitive function was worse in patients who received long-term HD than in HCs. Increased dialysis duration and hemoglobin level were predictive risk factors for decreased CBF in patients who received long-term HD.

CONCLUSIONS

Patients who received long-term HD with normal CBF had worse cognitive function, which may be related to increased dialysis duration.

The Association of Tacrolimus Formulation on Cerebral Blood Flow and Cognitive Function

Calcineurin inhibitors are inherent vasoconstrictors. Cerebral vasoconstriction can reduce cerebral blood flow (CBF), and negatively impact cerebrovascular response (CVR) to exercise, and cognitive function. The once-daily extended-release (LCP) tacrolimus has fewer side effects than the immediate-release (IR) tacrolimus. The role of calcineurin inhibitors on CBF and the impact of specific formulations of tacrolimus on CBF, CVR, and cognitive function are unknown. In this pilot study, we evaluated whether changing from IR tacrolimus to LCP tacrolimus modulates CBF, CVR, or cognitive function in kidney transplant (KT) recipients.

Methods

We randomized (2:1) 30 stable KT recipients on IR tacrolimus to intervention (switch to LCP tacrolimus) and control (continue IR tacrolimus) arms. We measured CBF, CVR, and cognitive function at baseline and at 12 wk. We used ANCOVA to evaluate changes in outcome variables, with baseline values and study arm as covariates. We used descriptive statistics with mean changes in outcome variables to compare the 2 groups.

Results

Participants were 51 ± 13 y old. There was no difference in plasma tacrolimus levels at baseline and at 12 wk in the 2 arms. The changes in CBF, resting middle cerebral artery velocity, CVR, and cognitive function were more favorable in the intervention arm than in the control group.

Conclusions

Changing IR tacrolimus to LCP tacrolimus may improve CBF, cerebrovascular dynamics, and cognitive function in KT recipients. Larger studies are needed to confirm these results.

Incident dementia in kidney transplantation recipients: a matched comparative nationwide cohort study in South Korea

BACKGROUND

Recent studies have shown that patients with end-stage renal disease (ESRD) are at elevated risk of dementia. However, whether kidney transplantation (KT) lowers the risk for incident dementia remains unclear.

METHODS

From the Korean National Health Insurance Service database, we identified incident KT recipients aged ≥40 years without any history of dementia between 2007 and 2015. We also established a pair of age-, sex-, and inclusion year-matched control cohorts of patients with incident dialysis-dependent ESRD and members of the general population (GP) without a history of dementia, respectively. Cases of incident all-cause dementia, including Alzheimer disease (AD), vascular dementia (VD), and other kinds of dementia, were obtained from baseline until December 31, 2017.

RESULTS

We followed 8,841 KT recipients, dialysis-dependent ESRD patients, and GP individuals for 48,371, 28,649, and 49,149 patient- years, respectively. Their mean age was 52.5 years, and 60.6% were male. Over the observation period, 55/43/19 KT recipients, 230/188/75 dialysis-dependent ESRD patients, and 38/32/14 GP individuals developed all-cause dementia/AD/VD. The risks of incident all-cause dementia, AD, and VD in KT recipients were similar to those in GP (hazard ratio: 0.74 [p = 0.20], 0.74 [p = 0.24], and 0.59 [p = 0.18], respectively) and significantly lower than those in dialysis-dependent ESRD patients (hazard ratio: 0.17 [p < 0.001], 0.16 [p < 0.001], and 0.16 [p < 0.001], respectively). Older age and diabetes mellitus at the time of KT were risk factors for incident all-cause dementia and AD in KT recipients.

CONCLUSION

This is the first study to show a beneficial impact of KT on incident dementia compared to dialysis dependency.

Association Between Long-Term Exposure to Fine Particulate Matter Constituents and Progression of Cerebral Blood Flow Velocity in Beijing: Modifying Effect of Greenness

Few studies have explored the effects of fine particulate matter (PM2.5) and its constituents on the progression of cerebral blood flow velocity (BFV) and the potential modifying role of greenness. In this study, we investigated the association of PM2.5 and its constituents, including sulfate (SO4 2-), nitrate (NO3 -), ammonium (NH4 +), organic matter (OM), and black carbon (BC), with the progression of BFV in the middle cerebral artery. Participants from the Beijing Health Management Cohort who underwent at least two transcranial Doppler sonography examinations during 2015-2020 were recruited. BFV change and BFV change rate were used to define the progression of cerebral BFV. Linear mixed effects models were employed to analyze the data, and the weighted quantile sum regression assessed the contribution of PM2.5 constituents. Additionally, greenness was examined as a modifier. Among the examined constituents, OM exhibited the strongest association with BFV progression. An interquartile range increase in PM2.5 and OM exposure concentrations was associated with a decrease of -16.519 cm/s (95% CI: -17.837, -15.201) and -15.403 cm/s (95% CI: -16.681, -14.126) in BFV change, and -10.369 cm/s/year (95% CI: -11.387, -9.352) and -9.615 cm/s/year (95% CI: -10.599, -8.632) in BFV change rate, respectively. Furthermore, stronger associations between PM2.5 and BFV progression were observed in individuals working in areas with lower greenness, those aged under 45 years, and females. In conclusion, reducing PM2.5 levels in the air, particularly the OM constituent, and enhancing greenness could potentially contribute to the protection of cerebrovascular health.

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.

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

SIGNIFICANCE STATEMENT

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL TRIALS INFORMATION

NCT03342183 .

Relationship between Lower Extremity Peripheral Arterial Disease and Mild Cognitive Impairment in Hemodialysis Patients

Background: The link between arterial stiffness and mild cognitive impairment (MCI) in patients on hemodialysis (HD) has been receiving increased attention. The purpose of this study was to investigate the relationship between cognitive function and ankle brachial index (ABI) and toe brachial index (TBI) values in patients on hemodialysis. Of the 100 participants (mean age: 67.9 years; average history of hemodialysis: 7.3 years). Of these, 46.0% had MCI. The MoCA-J scores were significantly higher in the ABI ≥ 1.06 group. However, the MoCA-J scores divided into the two groups according to the TBI cutoff value were not significantly different. In a multiple regression model with the MoCA-J scores as the objective variable, the ABI was a significantly associated factor. This study indicates that a low ABI might be associated with MCI.

The Influence of Healthy Habits on Cognitive Functions in a Group of Hemodialysis Patients

(1) Background: Cognitive impairment (CI) is more prevalent in hemodialysis (HD) patients than in the general population. The purpose of this study was to examine if behavioral, clinical, and vascular variables are linked with CI in individuals with HD. (2) Methods: Initially, 47 individuals with chronic HD volunteered to participate in the trial, but only 27 patients ultimately completed the Montreal Cognitive Assessment (MoCA) and the Computerized Cognitive Assessment Tool (CompBased-CAT). We collected information on smoking, mental activities, physical activity (Rapid Assessment of Physical Activity, RAPA), and comorbidity. The oxygen saturation (rSO2) and pulse wave velocity (PWV; IEM Mobil-O-Graph) of the frontal lobes were measured. (3) Results: Significant associations were discovered between MoCA and rSO2 (r = 0.44, p = 0.02 and r = 0.62, p = 0.001, right/left, respectively), PWV (r = -0.69, p = 0.0001), CCI (r = 0.59, p = 0.001), and RAPA (r = 0.72, p = 0.0001). Those who actively occupied their time during dialysis and non-smokers achieved higher cognitive exam results. A multivariate regression study demonstrated that physical activity (RAPA) and PWV had separate effects on cognitive performance. (4) Conclusions: Cognitive skills are related to inter-dialysis healthy habits (physical activity, smoking) and intra-dialysis activities (tasks and mind games). Arterial stiffness, oxygenation of the frontal lobes, and CCI were linked with CI.

Association between Cognitive Impairment and Malnutrition in Hemodialysis Patients: Two Sides of the Same Coin

Cognitive impairment and malnutrition are prevalent in patients on hemodialysis (HD), and they negatively affect the outcomes of HD patients. Evidence suggests that cognitive impairment and malnutrition may be associated, but clinical studies to assess this association in HD patients are lacking. The aim of this study was to evaluate the association between cognitive impairment evaluated by the Montreal Cognitive Assessment (MoCA) score and nutritional status evaluated by the malnutrition inflammation score (MIS) in HD patients. We enrolled 84 HD patients (44 males and 40 females; age: 75.8 years (63.5-82.7); HD vintage: 46.0 months (22.1-66.9)). The MISs identified 34 patients (40%) as malnourished; the MoCa scores identified 67 patients (80%) with mild cognitive impairment (MCI). Malnourished patients had a higher prevalence of MCI compared to well-nourished patients (85% vs. 70%; p = 0.014). MoCa score and MIS were negatively correlated (rho:-0.317; p < 0.01). Our data showed a high prevalence of MCI and malnutrition in HD patients. Low MoCA scores characterized patients with high MISs, and malnutrition was a risk factor for MCI. In conclusion, it is plausible that MCI and malnutrition are linked by common sociodemographic, clinical, and biochemical risk factors rather than by a pathophysiological mechanism.

Cerebral blood flow pulsatility and cerebral artery stiffness acutely decrease during hemodialysis

End-stage kidney disease (ESKD) is associated with increased arterial stiffness and cognitive impairment. Cognitive decline is accelerated in ESKD patients on hemodialysis and may result from repeatedly inappropriate cerebral blood flow (CBF). The aim of this study was to examine the acute effect of hemodialysis on pulsatile components of CBF and their relation to acute changes in arterial stiffness. In eight participants (age: 63 ± 18 years, men: 5), CBF was estimated using middle cerebral artery blood velocity (MCAv) assessed with transcranial Doppler ultrasound before, during, and after a single hemodialysis session. Brachial and central blood pressure, along with estimated aortic stiffness (eAoPWV) were measured using an oscillometric device. Arterial stiffness from heart to MCA was measured as the pulse arrival time (PAT) between electrocardiogram (ECG) and transcranial Doppler ultrasound waveforms (cerebral PAT). During hemodialysis, there was a significant reduction in mean MCAv (-3.2 cm/s, p < 0.001), and systolic MCAv (-13.0 cm/s, p < 0.001). While baseline eAoPWV (9.25 ± 0.80 m/s) did not significantly change during hemodialysis, cerebral PAT increased significantly (+0.027 , p < 0.001) and was associated with reduced pulsatile components of MCAv. This study shows that hemodialysis acutely reduces stiffness of arteries perfusing the brain along with pulsatile components of blood velocity.

The impact of hemodiafiltration on cognitive function in patients with end-stage renal disease

Background

Patients with end-stage renal disease are more likely to suffer cognitive impairment. Cognitive impairment may lead to long-term severe adverse consequences.

Purpose

To explore the impact of different blood purification therapy on cerebral blood flow and cognitive functions in end-stage renal disease.

Materials and methods

This prospective study evaluated patients with end-stage renal disease undergoing blood purification from January to March 2021. Matched healthy controls were also included. Participants performed neurocognitive measurements, including a mini-mental state examination, logical memory test-20-minutes delayed, verbal fluency test, digit span test, clock drawing test, and stroop color and word test C. In addition, we tested plasma amyloid-β protein levels, serum Fe and hemoglobin levels in blood samples. Cerebral blood flow was measured using pulsed pseudocontinuous arterial spin labeling. We analyzed and compared the correlation between cognitive function, biomarkers, and cerebral blood flow between patients and healthy subjects, as well as between patients with different treatments.

Results

A total of 44 patients with end-stage renal disease (mean age, 57.39 years ± 8.63) and 46 healthy controls (mean age, 56.15 years ± 6.40) were recruited. Patients receive hemodialysis three times a week, and 27 of them have been replaced hemodialysis for hemodiafiltration twice a month. The cognitive function of patients was worse than healthy controls (P < 0.05). The patients showed higher plasma concentrations of amyloid-β40, amyloid-β42, Tau, and pTau181 than healthy controls (P < 0.05). The group receiving both hemodialysis and hemodiafiltration had higher cerebral blood flow signal values in the left caudate nucleus (chuster-level P < 0.05, voxel-level P < 0.001). They also exhibited better verbal fluency function than the hemodialysis-only group (P < 0.05).

Conclusion

Patients with the end-stage renal disease showed widespread cognitive declines. Cerebral blood flow generally decreased in the cerebral cortex and increased in subcortical regions. The hemodiafiltration may protect verbal function by increasing cerebral blood flow in the left caudate.

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.

Risk factors for neurocognitive impairment and the relation with structural brain abnormality in children and young adults with severe chronic kidney disease

BACKGROUND

Severe chronic kidney disease (CKD) in children and young adults has shown to be associated with abnormal brain development, which may contribute to neurocognitive impairments. We aimed to investigate risk factors for neurocognitive impairment and investigate the relation with structural brain abnormalities in young severe CKD patients.

METHODS

This cross-sectional study includes 28 patients with severe CKD (eGFR < 30), aged 8-30 years (median 18.5 years), on different treatment modalities (pre-dialysis [n = 8], dialysis [n = 8], transplanted [n = 12]). We assessed neurocognitive functioning using a comprehensive test battery and brain structure by magnetic resonance imaging metrics of brain volume and white matter integrity (fractional anisotropy [FA] and mean diffusivity [MD] measured with diffusion tensor imaging). Multivariate regression and mediation analyses were performed between clinical CKD parameters, brain structure, and neurocognitive outcome.

RESULTS

A combination of risk factors (e.g., longer time since kidney transplantation, longer dialysis duration and late CKD onset) was significantly associated with lower intelligence and/or worse processing speed and working memory. Lower FA in a cluster of white matter tracts was associated with lower intelligence and mediated the relation between clinical risk factors and lower intelligence.

CONCLUSIONS

Young severe CKD patients with a prolonged duration of kidney replacement therapy, either dialysis or transplantation are at particular risk for impairments in intelligence, processing speed, and working memory. Disrupted white matter integrity may importantly contribute to these neurocognitive impairments. Prospective, longitudinal studies are needed to elucidate the mechanisms involved in CKD and treatment that affect white matter integrity and neurocognitive outcome in young patients. A higher resolution version of the Graphical abstract is available as Supplementary information.

Frailty, multimorbidity and sarcopaenia in haemodialysis patients

PURPOSE OF REVIEW

It is well recognised that haemodialysis patients have higher levels of multimorbidity, frailty and sarcopaenia. This review examines the current understanding of the three concepts in relation to the general population and haemodialysis patients, and the methods used to quantify them. It also looks at the interaction between multimorbidity, frailty and sarcopaenia in this patient group and proposes a new model that utilises muscle mass index and fat mass index as a surrogate representation of the three concepts.

RECENT FINDINGS

Multimorbidity in on the rise in the general population and this is one of the contributing factors to higher rates of chronic kidney disease, progression to end-stage renal disease and multimorbidity in haemodialysis patients. Malnutrition and haemodialysis induced end organ damage further contributes to muscle loss and frailty in this patient group. There is a significant overlap and interaction between multimorbidity, frailty and sarcopaenia in haemodialysis and their presence carries a significant impact on quality of life and survival. There are multiple scores for measuring multimorbidity, frailty and sarcopenia and there is no consensus on their utilisation in haemodialysis patients. We propose the use of fat mass index and muscle mass index model as a surrogate method for clinically quantifying multimorbidity, frailty and sarcopaenia.

SUMMARY

Effective public health policies are likely to have an impact on reducing the prevalence of multimorbidity and the development of end stage renal disease. Future research is required to develop interventions that are targeted at maintaining muscle mass and function in haemodialysis patients.

Healthy aging and chronic kidney disease

The world population is aging and the prevalence of noncommunicable diseases such as diabetes, hypertension, and chronic kidney disease (CKD) will increase significantly. With advances in medical treatment and public health, the human lifespan continues to outpace the health span in such a way that the last decade of life is generally spent in poor health. In 2015, the World Health Organization defined healthy aging as 'the process of developing and maintaining the functional ability that enables wellbeing in older age.' CKD is increasingly being recognized as a model of accelerated aging and is associated with physical performance decline, cognitive decline, falls and fractures, poor quality of life, loss of appetite, and inflammation. Frailty and dementia are the final pathways and key determinants of disability and mortality independent of underlying disease. CKD, dementia, and frailty share a triangular relationship with synergistic actions and have common risk factors wherein CKD accelerates frailty and dementia through mechanisms such as uremic toxicity, metabolic acidosis and derangements, anorexia and malnutrition, dialysis-related hemodynamic instability, and sleep disturbance. Frailty accelerates glomerular filtration decline as well as dialysis induction in CKD and more than doubles the mortality risk. Anorexia is one of the major causes of protein-energy malnutrition, which is also prevalent in the aging population and warrants screening. Healthcare systems across the world need to have a system in place for the prevention of CKD amongst high-risk older adults, focusing on screening for poor prognostic factors amongst patients with CKD such as frailty, poor appetite, and cognitive impairment and providing necessary person-centered interventions to reverse underlying factors that may contribute to poor outcomes.

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.