Can dialysis cause cognitive issues?

Does Dialysis Cause Cognitive Issues?

Yes, dialysis is associated with significant cognitive impairment, affecting approximately 60-76% of patients, with cognitive function declining both chronically over time and acutely during individual dialysis sessions. 1, 2, 3

Prevalence and Pattern of Cognitive Impairment

The cognitive burden in dialysis patients is substantial and multifaceted:

• Chronic cognitive impairment affects 60-76% of hemodialysis patients, with deficits most pronounced in attention, executive function, and memory domains compared to the general population 2, 3
• Acute intradialytic cognitive decline occurs in a majority of patients during individual hemodialysis sessions, with measurable deterioration in attention, language, abstraction, and delayed recall 2
• Only a minority of patients (not the majority) show significant individual cognitive fluctuations around the dialysis cycle, but when present, these fluctuations predominantly manifest as prolonged reaction times and psychomotor slowing after dialysis 1

Specific Cognitive Domains Affected

The pattern of impairment is not uniform across all cognitive functions:

• Attention and orientation are the most severely affected domains (standardized mean difference of -0.93 compared to general population), followed by executive function 3
• Memory impairment is moderate, with hemodialysis patients performing worse than both the general population and patients with non-dialysis-dependent chronic kidney disease 3
• In peritoneal dialysis patients, global cognitive function declines over 2 years (3MS scores declining from 84.8 to 83.1), though some specific domains like executive function and immediate memory may paradoxically improve 4

Risk Factors and Mechanisms

Dialysis-Dependent Factors

• Intradialytic hypotensive episodes are moderately associated with cognitive fluctuations during and after dialysis sessions 1
• Dialysis vintage (duration on dialysis) independently predicts cognitive decline, with longer time on dialysis associated with worse outcomes 1, 2
• Age is an independent predictor, with older patients experiencing more pronounced decline during dialysis sessions 2

Dialysis-Independent Factors

• Cerebrovascular disease is considered an important underlying cause of cognitive impairment in this population 5
• Hypoalbuminemia is significantly associated with deterioration in delayed memory, visuospatial skill, language ability, and general cognitive function 4
• Depression correlates with deterioration in both general and specific cognitive function 4
• Blood leukocyte count, sodium levels, and psychoactive medication use weakly predict cognitive fluctuations 1

Clinical Implications and Monitoring

Impact on Patient Outcomes

• Cognitive impairment at baseline is associated with greater hospitalization rates and lower dialysis modality survival, particularly when memory dysfunction is present 4
• Cognitive deficits may decrease quality of life, increase resource utilization, and result in suboptimal medical care due to difficulty following treatment recommendations 5
• The acute decline in cognition during dialysis sessions has significant implications for health literacy, self-management, and safety-sensitive activities like driving 2

Assessment Recommendations

• Cognitive development and statural growth should be monitored serially in pediatric peritoneal dialysis patients, as underdialysis may affect cognitive development, though the exact relationship between dialysis dose and normal development is unclear 6
• Patient-based quality of life assessment should be evaluated seriously as an outcome measure, using validated instruments with both generic and disease-specific measures administered at dialysis initiation and at appropriate intervals 6

Management Considerations

While the guidelines focus primarily on symptom management rather than cognitive impairment specifically, relevant approaches include:

• Optimizing dialysis adequacy may improve overall well-being, though evidence for direct cognitive benefit is limited 7
• Non-pharmacological interventions such as cognitive behavioral therapy, exercise, and social support are recommended for managing psychological symptoms that may compound cognitive issues 6
• Extended or more frequent hemodialysis shows statistical but uncertain clinical benefit on mental health components of quality of life 6

Critical Caveat

The cognitive decline during dialysis sessions represents an underrecognized clinical problem that warrants further research 2. Current guidelines do not provide specific protocols for screening or managing cognitive impairment in dialysis patients, despite its high prevalence and significant impact on patient outcomes. Clinicians should maintain heightened awareness of this issue and consider cognitive function when educating patients and planning care.