The Role of Dialysis in the Pathogenesis and Treatment of Dementia

Dearbhla M. Kelly


Nephrol Dial Transplant. 2019;34(7):1080-1083. 

In This Article

Does Modality Matter?

There are limited data and few longitudinal studies comparing cognitive function in patients with respect to different dialysis modalities. In a retrospective cohort study of incident dialysis patients in the USA from 2006 to 2008, the risk of dementia for patients who started on PD was 25% lower compared with those who started on HD, even adjusting for a comprehensive set of demographic and clinical characteristics in a well-matched analysis.[36]

There may be inherent selection bias however, as patients with pre-existing cognitive impairment may be precluded or discouraged from PD if unable to manage independently. Although patients with pre-existing dementia were excluded from analysis in the United States Renal Data System (USRDS) study, it is possible that significant differences in baseline cognitive function between the PD and HD groups affected results. Findings from 630 adults participating in the Chronic Renal Insufficiency Cohort Study who had cognitive assessments in late-stage CKD confirmed that predialysis cognitive impairment was independently associated with 78% lower odds of PD as the first dialysis modality.[1]

However, more recent work also reports that cognition (specifically MoCA executive scores) declines faster in HD patients than in PD ones.[37] A multicentre German study within the Choice of Renal Replacement Therapy (CORETH) project administered two validated neurocognitive tests, assessing executive functioning (Trail Making Test-B) and attention (d2-Revision-Test) to 271 patients at baseline and after 1 year, and again PD predicted better cognitive function than HD at follow-up.[38]