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

Neuropsychological Profile in Older Adults with End-Stage Kidney Disease during Kidney Transplantation Evaluation

BACKGROUND

End-stage chronic kidney disease (CKD) is a significant concern for older adults and is often associated with cognitive impairment (CI). The origin of this CI is multifactorial, involving vascular and metabolic factors. Additionally, renal treatments, including dialysis, may affect cognition. This study aimed to assess the neuropsychological profiles of these patients and understand the effects of dialysis treatment.

METHODS

We conducted an observational retrospective study including older adults with end-stage CKD attending for kidney transplantation (KT). Comprehensive neuropsychological assessments were conducted. Composite cognitive scores were computed. Multivariate regression models were used to assess associations between cognition and dialysis status.

RESULTS

We included 223 patients (151 treated with dialysis, 72 with conservative management), mean age of 73.5 ± 3.4. We observed a high prevalence of CI, around 30% for global cognition and affecting all neuropsychological domains. Patients treated with dialysis exhibited lower cognitive performance compared to those not undergoing dialysis, particularly in episodic (p = .031) and working memory (p = .024).

CONCLUSION

This study confirms the high prevalence of CI in end-stage CKD, with dialysis being associated with worse episodic and working memory compared to non-dialyzed participants. Future investigations are needed to track the long-term cognitive trajectory of patients on the KT waiting list and post-transplantation.

TRIAL REGISTRATION

Retrospectively registered, no 22-808 on July 7th, 2022, CNIL register number 22-5808.

The Clock Drawing Task reveals executive dysfunction in the dialysis population - an underrecognized and underestimated problem

AIM OF THE STUDY

The study aimed to assess the prevalence of executive function impairment among patients with chronic kidney disease (CKD) undergoing dialysis, with no subjective cognitive problems and with normal global cognition on the Mini-Mental State Examination (MMSE). We also investigated the relationship between cardiovascular risk factors and cognitive test results.

RATIONALE FOR THE STUDY

Patients with CKD, including those undergoing renal replacement therapy, are at a higher risk of developing cognitive impairment (CI) than the general population. Recent research has shown CI to be a growing problem among CKD patients worldwide. Yet, it remains underdiagnosed, even though it may significantly influence the lives of patients.

MATERIALS AND METHODS

In this cross-sectional, prospective study, 58 dialysis patients with no cognitive decline on the MMSE screening were assessed for executive function impairment using the Executive Clock-Drawing Task (CLOX). Moreover, past medical history, demographic data, and laboratory test results were collected.

RESULTS

The mean patient age was 59.47 ± 14.98 years, and the mean duration of dialysis was 45.93 ± 48.49 months. The prevalence of executive function impairment amounted to 8.6%. Moreover, remarkably similar pattern of clock drawing was observed, with numbers written outside the clock face in the CLOX1 test.

CONCLUSIONS

Executive dysfunctions in dialysis patients may manifest itself before the onset of global cognitive impairment. There appear to be a deficit in the spatial domain as well. Better education may play a protective role.

Contrasting Effects of an Atherogenic Diet and High-Protein/Unsaturated Fatty Acids Diet on the Accelerated Aging Mouse Model SAMP8 Phenotype

Background/Objectives: Aging has been extensively studied, with a growing interest in memory impairment by a neurobiological approach. Mitochondrial dysfunction is a hallmark of aging, contributing to the aging phenotype; therefore, mitochondrial interventions seem fundamental. The diet is a physiological approximation for modifying mitochondria, which could impact the age-related phenotype. Methods: We studied two diets with low-carbohydrate and high-fat compositions, differing in the amount of protein and the fat type disposable-the atherogenic diet Cocoa (high protein/high saturated fat/high cholesterol) and the South Beach diet (very high-protein/high-unsaturated fat)-on oxidative stress, mitochondrial state, and hippocampus-dependent memory in 3-month-old Senescence-Accelerated Mouse Model (SAMP8) seed over 3 months to determine their pro- or anti-aging effects. Results: Despite its bad reputation, the Cocoa diet reduces the reactive oxygen species (ROS) content without impacting the energy state and hippocampus-dependent spatial acuity. In contrast to the beneficial impact proposed for the South Beach diet, it induced a pro-aging phenotype, increasing oxidative damage and the levels of NR2B subunit of the NMDA, impairing energy and spatial acuity. Surprisingly, despite the negative changes observed with both diets, this led to subtle memory impairment, suggesting the activation of compensatory mechanisms preventing more severe cognitive decline. Conclusions: Our results demonstrated that diets usually considered good could be detrimental to the onset of aging. Also, probably due to the brain plasticity of non-aged animals, they compensate for the damage, preventing a more aggravated phenotype. Nevertheless, these silent changes could predispose or increase the risk of suffering pathologies at advanced age.

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.