Objective: There are few detailed data on cognition in patients undergoing dialysis. We evaluated the frequency of and risk factors for poor cognitive performance using detailed neurocognitive testing.Methods: In this cross-sectional cohort study, 314 hemodialysis patients from 6 Boston-area hemodialysis units underwent detailed cognitive assessment. The neuropsychological battery assessed a broad range of functions, with established age-, sex-, and education-matched normative scores. Principal component analysis was used to derive composite scores for memory and executive function domains. Risk factors for each domain were evaluated using linear regression adjusting for age, sex, race, and education status. Analyses were repeated in those with Mini-Mental State Examination (MMSE) score $24.Results: Compared with population norms, patients on dialysis had significantly poorer executive function but not memory performance, a finding that persisted in the subgroup with MMSE score $24. In adjusted analyses, vascular risk factors and vascular disease were associated with lower executive function (p , 0.01).Conclusions: There is a high frequency of poor cognitive performance in hemodialysis patients, primar- Cognitive impairment in dialysis is an increasingly important public health problem given the aging end-stage renal disease (ESRD) population and the increasing prevalence of diabetes and vascular disease. In older studies in hemodialysis patients, cognitive impairment, defined by poor performance on the Mini-Mental State Examination (MMSE), was present in 40% to 60%. 1-3 Despite the fact that the MMSE remains the most frequently used screening tool for cognitive impairment, it focuses on memory and largely neglects other cognitive domains such as executive function; accordingly, the MMSE may not be sufficient to detect more subtle degrees of cognitive impairment.The major causes of dementia in the general population are Alzheimer disease, which initially manifests with memory loss with later involvement of other cognitive domains, and vascular dementia, which primarily manifests with impairment in executive function. [4][5][6][7] Although it is likely that patients undergoing dialysis have similar causes for cognitive impairment as the general population, there are few studies that have attempted to distinguish the prevalence of and risk factors for each type of cognitive impairment in this population.The goals of this study were therefore to evaluate the frequency of and risk factors for poor cognitive performance in hemodialysis patients using detailed measures of multiple cognitive domains, From the Division of Nephrology (M.J.S., K

Background Both depression and cognitive impairment are common in hemodialysis patients, are associated with adverse clinical outcomes, and place an increased burden on health care resources. Study Design Cross-sectional cohort Setting & Participants 241 maintenance hemodialysis patients in the Boston area Predictor Depressive symptomatology, defined by a Center for Epidemiological Studies Depression Scale (CES-D) score of 16 or higher Outcome Performance on a detailed neurocognitive battery Results Mean age was 63.8 years, 49.0% were female, 21.6% were African American, and median dialysis duration was 13.8 months. There were 57 (23.7%) participants with significant depressive symptoms. In multivariable analysis adjusting for age, sex, education and other comorbid conditions, participants with and without depressive symptoms performed similarly on the Mini-Mental State Examination (p=0.4) and tests of memory. However, participants with greater depressive symptoms performed significantly worse on tests assessing processing speed, attention, and executive function, including Trails Making Test B (p=0.02) and Digit-Symbol Coding (p=0.01). Defining depression using a CES-D score ≥18 did not substantially change results. Limitations Cross-sectional design, absence of brain imaging Conclusions Hemodialysis patients with a greater burden of depressive symptoms perform worse on tests of cognition related to processing speed and executive function. Further research is needed to assess the effects of treating depressive symptoms on cognitive performance in dialysis patients.

Background Cardiovascular disease (CVD) and cognitive impairment are common in dialysis patients. Given the proposed role of microvascular disease on cognitive function, particularly cognitive domains that incorporate executive functions, we hypothesized that prevalent systemic CVD would be associated with worse cognitive performance in hemodialysis patients. Design Cross-sectional cohort Setting and Participants 200 maintenance hemodialysis patients without prior stroke from 5 Boston-area hemodialysis units Predictor CVD, defined by history of coronary disease or peripheral vascular disease Outcome Performance on a detailed neurocognitive battery. Primary analyses quantified cognitive performance using principal components analysis to reduce cognitive tests to a processing speed/executive function domain and a memory domain. Multivariable linear regression models adjusted for age, sex, education, race and other clinical and demographic characteristics. Results Mean (SD) age of participants was 62 (18) years and 75 (38%) had CVD. Individuals with CVD were older, more likely to be men, diabetic, and current or former smokers. In adjusted models, individuals with CVD performed 0.50 standard deviations worse (p<0.001) on tests assessing processing speed/executive function, while there was no difference in performance on tests of memory. Similar results were seen when assessing individual tests, with performance on the block design, digit symbol coding and Trail Making Tests A and B significantly associated with CVD in age, sex, education and race-adjusted analyses and approaching toward significance in fully adjusted models. Limitations CVD ascertainment dependent on patient recall and dialysis unit documentation. No brain imaging. Conclusions The presence of CVD is associated with worse cognitive performance on tests of processing speed and executive functioning in hemodialysis patients and identifies a high risk population for greater difficulty with complex tasks.

Background Cognitive impairment is common but often undiagnosed in patients with end-stage renal disease, in part reflecting limited validated and easily administered tools to assess cognitive function in dialysis patients. Accordingly, we assessed the utility of the Kidney Disease Quality of Life Cognitive Function (KDQOL-CF) scale in comparison to an extensive neuropsychological battery, building on a prior assessment of this potential cognitive screen. Study Design Cross-sectional cohort. Setting & Participants Maintenance hemodialysis patients at 6 Boston area dialysis units were administered an extensive neurocognitive battery and the KDQOL-CF at the beginning of a hemodialysis session. Predictors KDQOL-CF score, depression symptom burden, and demographic and clinical characteristics. Outcomes Neurocognitive performance classified into executive function and memory domains, determined using principal components analysis. Measurements Univariate and multivariable linear regression models adjusting for age, sex, race, and end-stage renal disease cause were used to evaluate the association between KDQOL-CF score and cognitive performance, and test metrics were determined for a KDQOL-CF cutoff score of 60 or less from a maximum score of 100. Results For 168 prevalent hemodialysis patients, KDQOL-CF score was 76 ± 19 and 40 (24%) had scores of 60 or less, consistent with self-identified worse cognitive performance. There was no significant correlation between KDQOL-CF score and either memory (P = 0.2 and P = 0.3) or executive function (P = 0.1 and P = 0.4) in univariate and multivariable models, respectively. There was a strong correlation between higher KDQOL-CF score and fewer depression symptoms (P <0.001). Sensitivity of the KDQOL-CF was poor (range, 0.28–0.36), with modest specificity (range, 0.77–0.81) for identifying worse executive function and memory. Limitations Cross-sectional study, modest population size, and abbreviated gold-standard cognitive battery. Conclusions The KDQOL-CF is a poor determinant of neurocognitive performance in hemodialysis patients, with limited sensitivity. To assess cognitive impairment in hemodialysis patients, better screening tests are essential.