Hemodialysis and cognitive impairment: many associated factors, but limited evidence

Two outcomes not to be confused

The authors searched four bibliographic databases for available studies through January 2026. Their review of reviews, accompanied by a meta-analysis, brings together five meta-analyses covering 97 associations examined.

Three meta-analyses focus on cognitive impairment and two on cognitive frailty. The authors emphasize the need to interpret these two outcomes separately. The supplied abstract does not detail their definitions or the tools used to measure them.

Associations with health status and dialysis characteristics

For cognitive impairment, older age, female sex, diabetes, cerebrovascular disease and multiple coexisting conditions are associated with a higher risk. Reduced physical performance, lower hemoglobin and inflammatory markers are also associated with this impairment. A higher level of education is associated with a lower risk.

For cognitive frailty, the synthesis identifies associations with factors including depression, a history of stroke, malnutrition and longer time on dialysis. Low-flux hemodialysis and hypotension between sessions are also among the associated factors. These findings alone do not justify recommending a change in dialysis technique.

A map of associations, not evidence of prevention

All but two associations are supported by low- or very-low-certainty evidence. The abstract does not specify which have moderate certainty: the source material therefore does not allow a robust ranking of the factors.

An association establishes neither a cause nor the effectiveness of an intervention. For example, the link between malnutrition and cognitive frailty does not demonstrate that a nutritional intervention would improve cognition. The authors call for higher-quality prospective studies to clarify these relationships.

What we can take away

This synthesis describes factors associated with cognitive difficulties in people receiving hemodialysis, but does not validate any preventive strategy. Its findings apply to this population, not to healthy adults.