Haemodynamics during dialysis and cognitive performance.

ABSTRACT

BACKGROUND AND AIMS: Persons receiving haemodialysis (HD) are at increased risk of cognitive impairment (CI). Since blood pressure (BP) fluctuations during HD may affect cerebral perfusion - and subsequently cognitive function - we examined the relationship between dialytic BP fluctuation and cognitive outcomes. METHODS: We included HD patients without diagnosed dementia who were 50 years or older. Using established methods, we classified participants' in CI categories (none to mild and moderate to severe) based on results of a neurocognitive battery. We collected demographic and laboratory data from dialysis unit records, as well as all BP measurements from 12 dialysis sessions. We tested the association between CI and BP fluctuation, adjusting for demographic and laboratory variables. RESULTS: Our study enrolled 39 patients; 25 had moderate to severe CI. The normal to mild CI group and the moderate to severe patients had similar degrees of BP fluctuation (average minimum systolic BP (SBP) 107.6 ± 18.7 vs 110.2 ± 18.6 mmHg, maximum drop in SBP 32.6 ± 10.2 vs 35.4 ± 15.0 mmHg; proportion of sessions with SBP < 90 mmHg 0.2 ± 0.3 vs 0.2 ± 0.3; average change in SBP, pre to post HD 10.2 ± 12.4 vs 11.8 ± 16.4 mmHg, all P > 0.55). There was no association between BP variables and performance on individual cognitive tests. Multivariable analysis showed that older age and non-Caucasian race were associated with a reduction in cognitive scores. CONCLUSIONS: There was no cross-sectional association between dialytic BP changes and cognitive performance.