Associations of cardiovascular disease and blood pressure with cognition in hemodialysis patients: The Osaka Dialysis Complication Study

Background Previous studies have reported mixed results regarding the contributions of cardiovascular disease (CVD) and blood pressure (BP) to cognitive impairment in chronic kidney disease. Methods This was a cross-sectional study in 1213 patients on maintenance hemodialysis from 17 dialysis units in Japan. The main exposures were prior CVD and BP components including systolic BP (SBP) and diastolic BP (DBP). The outcome was low cognitive function evaluated with the Modified Mini-Mental State (3MS) examination with a cut-off level of 3MS Results The median age was 67 years, median duration of dialysis was 71 months, 37% were women, 39% had diabetic kidney disease and 36% had any pre-existing CVD. Median (interquartile range) of 3MS score was 91 (82-97), and 240 patients (20%) had 3MS <80. Logistic regression analysis showed that 3MS <80 was associated with the presence of any prior CVD, particularly prior stroke. 3MS <80 was associated with lower DBP but not with SBP. When patients were stratified by the presence of prior stroke, lower DBP, higher age and lower education level were factors associated with 3MS <80 in both subgroups. In the subgroup of patients without prior stroke, diabetic kidney disease was an additional factor associated with 3MS Conclusions Prior stroke and lower DBP were associated with 3MS <80 in hemodialysis patients. These findings support the hypothesis that these vascular factors contribute to low cognitive performance in patients undergoing hemodialysis.