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

Subjective cognitive complaints in end-stage renal disease: a systematic review and meta-analysis

Cognitive impairment is common in patients with end-stage renal disease (ESRD) and is associated with compromised quality of life and functional capacity, as well as worse clinical outcomes. Most previous research and reviews in this area were focused on objective cognitive impairment, whereas patients' subjective cognitive complaints (SCCs) have been less well-understood. This systematic review aimed to provide a broad overview of what is known about SCCs in adult ESRD patients. Electronic databases were searched from inception to January 2022, which identified 221 relevant studies. SCCs appear to be highly prevalent in dialysis patients and less so in those who received kidney transplantation. A random-effects meta-analysis also shows that haemodialysis patients reported significantly more SCCs than peritoneal dialysis patients (standardised mean difference -0.20, 95% confidence interval -0.38 to -0.03). Synthesis of longitudinal studies suggests that SCCs remain stable on maintenance dialysis treatment but may reduce upon receipt of kidney transplant. Furthermore, SCCs in ESRD patients have been consistently associated with hospitalisation, depression, anxiety, fatigue, and poorer quality of life. There is limited data supporting a strong relation between objective and subjective cognition but preliminary evidence suggests that this association may be domain-specific. Methodological limitations and future research directions are discussed.

The Impact of Intradialytic Cognitive and Physical Training Program on the Physical and Cognitive Abilities in End-Stage Kidney Disease Patients: A Randomized Clinical Controlled Trial

BACKGROUND

Hemodialysis (HD) patients have lower cognitive functioning and reduced physical fitness than age-matched healthy individuals. Clinicians typically do not recognize the declining cognitive performance in these patients; therefore, cognitive impairment is greatly underestimated and not appropriately treated. This study aimed to evaluate the impact on cognitive function of combining cognitive training with physical exercise and physical performance in HD patients.

METHODS

Using a randomized, single-blinded control design, forty-four HD patients were recruited and randomly assigned to either an intradialytic physical exercise and cognitive training program (EXP group; n = 22; 54% male; 65.7 ± 9.7 years; 77.1 ± 21.9 kg; body mass index 26.8 ± 6.0) or a standard care control group (CON group; n = 21; 77% male; 67.2 ± 12.5 years; 74.2 ± 14.3 kg; body mass index 25.9 ± 3.8). The EXP group performed intradialytic cycling and cognitive training three days per week for 12 weeks. Study outcomes were assessed by the Symbol Digit Modalities Test (SDMT), Montreal Cognitive Assessment (MoCA), 10-repetition sit-to-stand test (10-STS), handgrip strength test (HGS), and stork balance test.

RESULTS

The results showed a significant time*group interaction effect for SDMT (p < 0.001; η2 = 0.267) and MoCA (p < 0.001; η2 = 0.266). Moreover, no significant interaction was observed for 10-STS, HGS, and stork balance test (p > 0.05).

CONCLUSIONS

Our findings suggest that incorporating intradialytic cognitive and physical exercise training could help to improve the functional status of HD patients. The innovative, nonpharmacological, bimodal intervention is cost-effective, safe, and easy to implement during the intradialytic period and offers a potential impact on patients' quality of life and well-being.

Role of the CD40-CD40 Ligand Pathway in Cardiovascular Events, Neurological Alterations, and Other Clinical Complications of Chronic Hemodialysis Patients: Protective Role of Adsorptive Membranes

Despite the recent advances in dialysis technology, mortality rate of chronic uremic patients still remains excessively high: of note, in comparison to age- and sex-matched healthy controls, this frail population shows a higher incidence of infections, cancer, cognitive decline, and, in particular, major adverse cardiovascular events (MACE) that represent nowadays the first cause of mortality. Several traditional and nontraditional factors contribute to this increased risk for MACE and accelerated cellular senescence: among these, inflammation has been shown to play a key role. The costimulatory pathway CD40-CD40 Ligand (CD40L) is harmfully activated during inflammation and uremia-associated clinical complications: in particular, the soluble form of CD40L (sCD40L) can bind to the CD40 receptor triggering a cascade of detrimental pathways in immune and nonimmune cells. In this narrative review, we summarize the current concepts of the biological role of the CD40-CD40L pathway in uremia-associated organ dysfunction, focusing on the above-described main causes of mortality. Moreover, we discuss the interaction of the CD40-CD40L pathway with extracellular vesicles, microparticles recently identified as new uremic toxins. The biological effects of sCD40L in MACE, cognitive decline, infections, and cancer will be also briefly commented. Last, based on recent studies and ongoing clinical trials, we herein describe the modulatory activity of adsorptive dialysis membranes in polymethylmethacrylate on CD40-CD40L detrimental activation.

Patterns of Cognitive Impairment in Hemodialysis Patients and Related Factors including Depression and Anxiety

INTRODUCTION

Hemodialysis patients are at higher risk of developing cognitive impairment, but the pattern of affected cognitive domains is still undetermined. Little is also known about the symptoms of depression and anxiety in hemodialysis patients.

METHODS

In this cross-sectional study, we included 74 consecutive adult patients undergoing hemodialysis. Cognitive functions were assessed using the Addenbrooke Cognitive Test III. In addition, all patients were screened for symptoms of depression and anxiety using the Hospital Anxiety and Depression Scale.

RESULTS

The mean age of hemodialysis patients was 65.69 ± 14 years. Among the patients, there were 27% and 31% of patients with mild cognitive impairment and suspected dementia, respectively. In the group of patients with suspected dementia, all cognitive functions had significantly lower values compared to these functions in incognitively unimpaired and mild cognitive impairment patients. The most impaired domain was verbal fluency, which reflects impairments in executive function. Depression and anxiety symptoms were observed in 28% and 22% of patients, respectively. Patients with anxiety symptoms had higher levels of endogenous creatinine, parathyroid hormone, and hemoglobin, as well as decreased creatinine clearance, being younger and less educated. No factors contributing to the occurrence of depressive symptoms were found.

CONCLUSION

Cognitive dysfunction is a significant problem in hemodialysis patients. Our study showed that the prevalence of cognitive impairment and depression and anxiety symptoms in hemodialysis patients was high. The domain of executive functions was most affected. Furthermore, creatinine, parathyroid hormone, hemoglobin levels, creatinine clearance, and education affected the anxiety scale score.

The role of subjective cognitive complaints in self-management among haemodialysis patients: a cross-sectional study

Background

Subjective cognitive complaints refer to self-experienced difficulties with everyday cognitive tasks. Although there has been a fair amount of research on cognitive impairments and cognitive complaints in end-stage renal disease, the practical implications of these complaints remain unclear. The current study aims to examine the associations of cognitive complaints with sociodemographic and clinical variables, mood, as well as key patient-reported outcomes, i.e., self-efficacy, self-management skills, and treatment adherence.

Methods

A total of 305 haemodialysis patients (mean age = 53.97 years, 42.6% female) completed the Kidney Disease Quality of Life Cognitive Function subscale, a brief measure of cognitive complaints. The recommended cut-off point of 60 was used to identify probable cognitive impairment. Measures of self-efficacy, self-management skills (i.e., symptom coping, health monitoring, health service navigation), treatment adherence, and mood symptoms were also administered. Between-group comparisons and correlational analyses were performed to examine associations of cognitive complaints with sociodemographic, clinical, and health behaviour variables. Mediation analyses were also conducted to investigate the mediating role of self-efficacy on the relationship between cognitive complaints and treatment adherence.

Results

Nearly a quarter (23.0%) of haemodialysis patients reported cognitive complaints indicative of clinical impairments. Risk of probable impairments was higher for patients with hypertension, diabetes, those diagnosed with end-stage renal disease at an older age, and those with shorter time on dialysis. Subjective cognitive complaints (both rates of probable impairments as per cut-off and continuous scores) were significantly associated with lower disease and treatment self-efficacy, poorer self-management skills, lower treatment adherence, as well as higher symptoms of distress. Mediation analysis indicated that treatment self-efficacy mediated the relationship between cognitive complaints and treatment adherence.

Conclusions

The current study demonstrated the clinical characteristics of haemodialysis patients who report cognitive complaints indicative of probable cognitive impairments and showed the associations of these complaints with self-management outcomes. Future studies should adopt more comprehensive measures of cognitive complaints and longitudinal designs to confirm the current findings.

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.

Patient Perspectives on the Use of Frailty, Cognitive Function, and Age in Kidney Transplant Evaluation

BACKGROUND

The allocation of scarce deceased donor kidneys is a complex process. Transplant providers are increasingly relying on constructs such as frailty and cognitive function to guide kidney transplant (KT) candidate selection. Patient views of the ethical issues surrounding the use of such constructs are unclear. We sought to assess KT candidates' attitudes and beliefs about the use of frailty and cognitive function to guide waitlist selection.

METHODS

KT candidates were randomly recruited from an ongoing single-center cohort study of frailty and cognitive function. Semi-structured interviews were conducted, and thematic analysis was performed. Inductively derived themes were mapped onto bioethics principles.

RESULTS

Twenty interviews were conducted (65% contact rate, 100% participation rate) (60% male; 70% White). With respect to the use of frailty and cognitive function in waitlisting decisions, four themes emerged in which participants: (1) valued maximizing a scarce resource (utility); (2) prioritized equal access to all patients (equity); (3) appreciated a proportional approach to the use of equity and utility (precautionary utility); and (4) sought to weigh utility- and equity-based concerns regarding social support. While some participants believed frailty and cognitive function were useful constructs to maximize utility, others believed their use would jeopardize equity. Patients were uncomfortable with using single factors such as frailty or cognitive impairment to deny someone access to transplantation; participants instead encouraged using the constructs to identify opportunities for intervention to improve frailty and cognitive function prior to KT.

CONCLUSIONS

KT candidates' values mirrored the current allocation strategy, seeking to balance equity and utility in a just manner, albeit with conflicting viewpoints on the appropriate use of frailty and cognitive impairment in waitlisting decisions.

Neuropsychological Assessment of Cognitive Impairment in Kidney Transplantation (NAsKiT) and its related risk factors: a study protocol

BACKGROUND

Association of cognitive impairment with chronic kidney disease has been reported over the last decade. Individuals show better cognitive performance after kidney transplantation than individuals on dialysis but are more likely to be affected by cognitive impairment than age-matched comparison groups. Better knowledge of the prevalence as well as course and profile of cognitive impairment is important for the design of future studies assessing the clinical impact of cognitive impairment and developing management strategies. The goal of our study is to examine the extent of cognitive impairment before and after transplantation and to derive a distinct profile of cognitive function using standard neurocognitive tests. Furthermore, we aim to assess whether transplantation per se leads to an improvement in cognitive performance.

METHODS

We are conducting a prospective single-center cohort study involving 100 kidney transplant individuals. Individuals who are wait-listed to receive a kidney transplantation or have already received one will be included in this study. Individuals will undergo a battery of detailed neurocognitive tests at baseline (in part before surgery), and then 3 and 12 months afterwards. Furthermore, the enrolled patients will complete a validated German version of the Cognitive Failure Questionnaire for self-assessment (s-CFQ) as well as the Hospital Anxiety and Depression Scale -Deutsche (HADS-D), a self-report screening instrument with two scales that capture anxiety and depression. In addition, a hair sample will be taken at each measurement time point for the determination of hair cortisol levels as a parameter for the cumulative hypothalamic-pituitary-adrenocortical axis activity over the previous three months. The primary outcome measure will be (a) the effect of kidney transplantation on the cognitive performance up to 12 months after transplantation and (b) the course of cognitive performance following kidney transplantation over time.

DISCUSSION

The results of our study have potentially important implications for the prevention and treatment of cognitive impairment in kidney transplant individuals. By increasing our knowledge of the neurocognitive profile and assigning the corresponding deficits, it might be possible to create an individualized training program to positively impact cognitive deficits in kidney transplant patients.