Longitudinal changes in diffusion tensor imaging in hemodialysis patients.

INTRODUCTION: Hemodialysis patients have increased white matter and gray matter pathology in the brain relative to controls based on MRI. Diffusion tensor imaging is useful in detecting differences between hemodialysis and controls but has not identified the expected longitudinal decline in hemodialysis patients. In this study we implemented specialized post-processing techniques to reduce noise to detect longitudinal changes in diffusion tensor imaging parameters and evaluated for any association with changes in cognition. METHODS: We collected anatomical and diffusion MRIs as well as cognitive testing from in-center hemodialysis patients at baseline and 1 year later. Gray matter thickness, white matter volume, and white matter diffusion tensor imaging parameters were measured to identify longitudinal changes. We analyzed the diffusion tensor imaging parameters by averaging the whole white matter and using a pothole analysis. Eighteen hemodialysis patients were included in the longitudinal analysis and 15 controls were used for the pothole analysis. We used the NIH Toolbox Cognition Battery to assess cognitive performance over the same time frame. FINDINGS: Over the course of a year on hemodialysis, we found a decrease in white matter fractional anisotropy across the entire white matter (p < 0.01), and an increase in the number of white matter fractional anisotropy voxels below pothole threshold (p = 0.03). We did not find any relationship between changes in whole brain structural parameters and cognitive performance. DISCUSSION: By employing noise reducing techniques, we were able to detect longitudinal changes in diffusion tensor imaging parameters in hemodialysis patients. The fractional anisotropy declines over the year indicate significant decreases in white matter health. However, we did not find that declines in fractional anisotropy was associated with declines in cognitive performance.

Characterization of diffusion MRI using the mean apparent propagator model in hemodialysis patients: A pilot study.

To better understand documented cognitive decline in hemodialysis (HD) patients, diffusion MRI (dMRI) has been used to characterize brain anatomical deficits relative to controls. Studies to this point have primarily used diffusion tensor imaging (DTI) to model the three-dimensional diffusion of water in HD patients, with DTI parameters reflecting underlying microstructural changes of brain tissue. Since DTI has some limitations in characterizing tissue microstructure, some of which may be complicated by HD, we explored the use of the mean apparent propagator (MAP) model to describe diffusion in HD patients. We collected anatomical T1 and T2 FLAIR MRIs as well as multi-shell dMRI in ten HD participants and ten age-matched controls. The T1 and T2 FLAIR MRIs were used for tissue segmentation and identification of white matter hyperintensity, respectively. Multi-shell dMRI data were used to estimate MAP and DTI diffusion models. Each model was then used to characterize the differences between the HD cohort and the age-matched controls in normal appearing white matter, subcortical gray matter, corpus callosum (CC) and bilateral radiata (Rad). As expected, parameters of both DTI and MAP models of dMRI were significantly different in HD participants compared to controls. However, some MAP parameters suggested additional tissue microstructural changes in HD participants, such as increased axonal diameter. Measurements of non-Gaussianity indicated that MAP provided better a diffusion estimate than DTI, and MAP appeared to provide a more accurate measure of anisotropy in Rad, based on measures of the Rad/CC ratio. In conclusion, parameters of the MAP and DTI models were both sensitive to changes in diffusivity in HD participants compared to controls; however, the MAP model appeared to provide additional detailed information about changes in brain tissue microstructure.

Best Case/Worst Case: protocol for a multisite randomised clinical trial of a scenario planning intervention for patients with kidney failure.

INTRODUCTION: Given the burdens of treatment and poor prognosis, older adults with kidney failure would benefit from improved decision making and palliative care to clarify goals, address symptoms, and reduce unwanted procedures. Best Case/Worst Case (BC/WC) is a communication tool that uses scenario planning to support patients' decision making. This article describes the protocol for a multisite, cluster randomised trial to test the effect of training nephrologists to use the BC/WC communication tool on patient receipt of palliative care, and quality of life and communication. METHODS AND ANALYSIS: We are enrolling attending nephrologists, at 10 study sites in the USA, who see outpatients with advanced chronic kidney disease considering dialysis. We aim to enrol 320 patients with an estimated glomerular filtration rate of ≤24 mL/min/1.73 m2 who are age 60 and older and have a predicted survival of 18 months or less. Nephrologists will be randomised in a 1:1 ratio to receive training to use the communication tool (intervention) at study initiation or after study completion (wait-list control). Patients in the intervention group will receive care from a nephrologist trained to use the BC/WC communication tool. Patients in the control group will receive usual care. Using chart review and surveys of patients and caregivers, we will test the efficacy of the BC/WC intervention with receipt of palliative care as the primary outcome. Secondary outcomes include intensity of treatment at the end of life, the effect of the intervention on quality of communication (QOC) between nephrologists and patients (using the QOC scale), the change in quality of life (using the Functional Assessment of Chronic Illness Therapy-Palliative Care scale) and receipt of dialysis. ETHICS AND DISSEMINATION: Approvals have been granted by the Institutional Review Board at the University of Wisconsin (ID: 2022-0193), with each study site ceding review to the primary IRB. All nephrologists will be consented and given a copy of the consent form. No patients or caregivers will be recruited or consented until their nephrology provider has chosen to participate in the study. Results will be disseminated via submission for publication in a peer-reviewed journal and at national meetings. TRIAL REGISTRATION NUMBER: NCT04466865.

The Relationship between Cerebrovascular Reactivity and Cerebral Oxygenation during Hemodialysis.

BACKGROUND: Patients with kidney failure treated with hemodialysis (HD) may be at risk for cerebral hypoperfusion due to HD-induced BP decline in the setting of impaired cerebral autoregulation. Cerebrovascular reactivity (CVR), the cerebrovascular response to vasoactive stimuli, may be a useful indicator of cerebral autoregulation in the HD population and identify those at risk for cerebral hypoperfusion. We hypothesize that CVR combined with intradialytic BP changes will be associated with declines in cerebral oxygenation saturation (ScO2) during HD. METHODS: Participants completed the MRI scans on a non-HD day and cerebral oximetry during HD. We measured CVR with resting-state fMRI (rs-fMRI) without a gas challenge and ScO2 saturation with near-infrared spectroscopy. Regression analysis was used to examine the relationship between intradialytic cerebral oxygen desaturation, intradialytic BP, and CVR in different gray matter regions. RESULTS: Twenty-six patients on HD had complete data for analysis. Sixteen patients were men, 18 had diabetes, and 20 had hypertension. Mean±SD age was 65.3±7.2 years, and mean±SD duration on HD was 11.5±9.4 months. CVR in the anterior cingulate gyrus (ACG; P=0.03, r2 =0.19) and insular cortex (IC; P=0.03, r2 =0.19) regions negatively correlated with decline in intradialytic ScO2. Model prediction of intradialytic ScO2 improved when including intradialytic BP change and ultrafiltration rate to the ACG rsCVR (P<0.01, r2 =0.48) and IC rsCVR (P=0.02, r2 =0.35) models, respectively. CONCLUSIONS: We found significant relationships between regional rsCVR measured in the brain and decline in intradialytic ScO2. Our results warrant further exploration of using CVR in determining a patient's risk of cerebral ischemic injury during HD.

Risk factors for intradialytic decline in cerebral perfusion and impaired cerebral autoregulation in adults on hemodialysis.

INTRODUCTION: Hemodialysis (HD) patients have significant burden of cerebral ischemic pathology noted on brain imaging. These ischemic type lesions maybe due to cerebral hypoperfusion that may be occurring during blood pressure (BP) fluctuations commonly noted during HD sessions. We evaluated changes in cerebral perfusion and measured an index of cerebral autoregulation (CA index) during HD to identify potential risk factors for intradialytic decline in cerebral perfusion and impaired cerebral autoregulation. METHODS: In this cross-sectional study, we included HD patients age 50 years or older receiving conventional in-center HD. We measured cerebral perfusion during HD, using cerebral oximetry, and calculated the correlation between cerebral perfusion and BP during HD as an index of CA. We measured the association between potential risk factors for intradialytic decline in cerebral perfusion and CA index. FINDINGS: We included 32 participants and 118 HD sessions in our analysis. The mean ± SD decline in cerebral oxygen saturation during HD was 6.5% ± 2.9% with a relative decline from baseline values of 9.2% ± 4.4%. Greater drop in systolic BP (SBP) during HD was associated with decline in cerebral oxygen saturation, p = 0.02. Impaired CA index was noted in 37.3% of HD sessions. Having diabetes and >20 mmHg drop in SBP during HD were associated with increased (worse) CA index with an increase of 0.24 95%CI [0.06, 0.41] for diabetes and increase of 0.43 95%CI [0.27, 0.56] for a >20 mmHg drop in SBP during HD. DISCUSSION: Cerebral perfusion can decline during HD and is associated with changes in systemic BP. This may be due to impaired cerebral autoregulation in HD patients. Risk factors for worse CA index include diabetes and >20 mmHg drop in SBP during HD. This study highlights the risk of intradialytic decline in cerebral perfusion and impaired cerebral autoregulation in HD patients.

Changes in Cerebral Volume and White Matter Integrity in Adults on Hemodialysis and Relationship to Cognitive Function.

INTRODUCTION: Patients on hemodialysis (HD) have a significant burden of cognitive impairment. Characterizing the cerebral structural changes in HD patients compared to healthy controls and evaluating the relationship of cerebral structural integrity with cognitive performance in HD patients can help clarify the pathophysiology of the cognitive impairment in HD patients. METHODS: In this cross-sectional study, in-center HD patients ≥50 years of age underwent brain structural and diffusion MRIs and cognitive assessment using the NIH Toolbox cognition battery. The cerebral imaging measures of the HD participants were compared to imaging from age-matched controls. Gray matter volume, white matter volume, and white matter integrity determined by diffusion tensor imaging parameters (including fractional anisotropy [FA]) were measured in both cohorts to determine differences in the cerebral structure between HD participants and healthy controls. The association between cognitive performance on the NIH Toolbox cognition battery and cerebral structural integrity was evaluated using multiple linear regression models. RESULTS: We compared imaging measures form 23 HD participants and 15 age-matched controls. The HD participants had decreased gray matter volumes (526.8 vs. 589.5 cm3, p < 0.01) and worsened white matter integrity overall (FA values of 0.2864 vs. 0.3441, p < 0.01) within major white matter tracts compared to healthy controls. Decreases in white matter integrity in the left superior longitudinal fasciculus was associated with lower executive function scores (r2 = 0.24, p = 0.02) and inferior longitudinal fasciculus with lower memory scores (r = 0.25 and p = 0.03 for left and r2 = 0.21 and p = 0.03 for right). CONCLUSIONS: HD patients have a pattern of decreased white matter integrity and gray matter atrophy compared to controls. Decreases in white matter integrity were associated with decreased cognitive performance in the HD population.

Effects of intensive versus standard blood pressure control on domain-specific cognitive function: a substudy of the SPRINT randomised controlled trial.

BACKGROUND: Results from the Systolic Blood Pressure Intervention Trial (SPRINT) showed that intensive control of systolic blood pressure significantly reduced the occurrence of mild cognitive impairment, but not probable dementia. We investigated the effects of intensive lowering of systolic blood pressure on specific cognitive functions in a preplanned substudy of participants from SPRINT. METHODS: SPRINT was an open-label, multicentre, randomised controlled trial undertaken at 102 sites, including academic medical centres, Veterans Affairs medical centres, hospitals, and independent clinics, in the USA and Puerto Rico. Participants were adults aged 50 years or older with systolic blood pressure higher than 130 mm Hg, but without diabetes, history of stroke, or dementia. Participants were randomly assigned (1:1) to a systolic blood pressure goal of less than 120 mm Hg (intensive treatment) versus less than 140 mm Hg (standard treatment). All major classes of antihypertensive agents were included. A subgroup of randomly assigned participants including, but not limited to, participants enrolled in an MRI substudy was then selected for a concurrent substudy of cognitive function (target 2800 participants). Each individual was assessed with a screening cognitive test battery and an extended cognitive test battery at baseline and biennially during the planned 4-year follow-up. The primary outcomes for this substudy were standardised composite scores for memory (Logical Memory I and II, Modified Rey-Osterrieth Complex Figure [immediate recall], and Hopkins Verbal Learning Test-Revised [delayed recall]) and processing speed (Trail Making Test and Digit Symbol Coding). SPRINT was registered with ClinicalTrials.gov, NCT01206062. FINDINGS: From Nov 23, 2010, to Dec 28, 2012, 2921 participants (mean age 68·4 years [SD 8·6], 1080 [37%] women) who had been randomly assigned in SPRINT were enrolled in the substudy (1448 received intensive treatment and 1473 received standard treatment). SPRINT was terminated early due to benefit observed in the primary outcome (composite of cardiovascular events). After a median follow-up of 4·1 years (IQR 3·7-5·8), there was no between-group difference in memory, with an annual decline in mean standardised domain score of -0·005 (95% CI -0·010 to 0·001) in the intensive treatment group and -0·001 (-0·006 to 0·005) in the standard treatment group (between-group difference -0·004, 95% CI -0·012 to 0·004; p=0·33). Mean standardised processing speed domain scores declined more in the intensive treatment group (between-group difference -0·010, 95% CI -0·017 to -0·002; p=0·02), with an annual decline of -0·025 (-0·030 to -0·019) for the intensive treatment group and -0·015 (-0·021 to 0·009) for the standard treatment group. INTERPRETATION: Intensive treatment to lower systolic blood pressure did not result in a clinically relevant difference compared with standard treatment in memory or processing speed in a subgroup of participants from SPRINT. The effect of blood pressure lowering might not be evident in specific domains of cognitive function, but instead distributed across multiple domains. FUNDING: National Heart, Lung, and Blood Institute, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute on Aging, National Institute of Neurological Disorders and Stroke, and the Alzheimer's Association.

The Relationship between Dialysis Metrics and Patient-Reported Cognition, Fatigue, and Physical Function.

INTRODUCTION: The impact of achieving hemodialysis laboratory and hemodynamic quality metrics on patient-reported outcomes (PROs) is unknown. OBJECTIVE: To determine if meeting dialysis laboratory quality of care measures is associated with improved PROs. METHODS: In this cross-sectional study, we measured the relationship between dialysis patients' Patient Reported Outcome Measurement Information System (PROMIS) scores and commonly used dialysis quality of care measures. RESULTS: PROMIS surveys were administered to 92 dialysis patients. The mean ± SD scores demonstrated higher fatigue (55.0 ± 9.8) and lower physical function (37.9 ± 7.9) but similar cognition (50.3 ± 10.9) compared to general population normative scores of 50 ± 10. Dialysis patients meeting Kt/V goals had no better scores than those who did not. Meeting the hemoglobin (Hgb) value of ≥10 g/dL was associated with a lower fatigue score, but no difference in cognitive or physical function scores. Meeting the serum albumin goal of ≥4.0 mg/dL was associated with a higher physical function score but made no difference for cognitive function or fatigue score. As a continuous variable, a higher Hgb was associated with lower reported fatigue (HR -1.74 95%, CI [-3.09, -0.39]), but no other measures were associated with PRO scores when adjusted for demographics and comorbidities. CONCLUSIONS: We found little association between measures currently used to assess the quality of dialysis care and PROs. Encouraging improved utilization of PROs and incorporating PROs into quality measurements might give a more robust assessment of quality of care. Future studies should assess the benefits of this approach.

Intradialytic Cerebral Hypoperfusion as Mechanism for Cognitive Impairment in Patients on Hemodialysis.

The high frequency of cognitive impairment in individuals on hemodialysis is well characterized. In-center hemodialysis patients are disproportionately affected by cognitive impairment compared with other dialysis populations, identifying hemodialysis itself as a possible factor. The pathophysiology of cognitive impairment has multiple components, but vascular-mediated cerebral injury appears to contribute based on studies demonstrating increased cerebral ischemic lesions and atrophy in brain imaging of patients on hemodialysis. Patients on hemodialysis may be at increased risk for cerebral ischemic injury disease due to vasculopathy associated with ESKD and from their comorbid diseases, such as hypertension and diabetes. This review focuses on the intradialytic cerebral hypoperfusion that can occur during routine hemodialysis due to the circulatory stress of hemodialysis. This includes a review of current methods used to monitor intradialytic cerebral perfusion and the structural and functional cognitive outcomes that have been associated with changes in intradialytic cerebral perfusion. Monitoring of intradialytic cerebral perfusion may become clinically relevant as nephrologists try to avoid the cognitive complications seen with hemodialysis. Identifying the appropriate methods to assess risk for cerebral ischemic injury and the relationship of intradialytic cerebral hypoperfusion to cognitive outcomes will help inform the decision to use intradialytic cerebral perfusion monitoring in the clinical setting as part of a strategy to prevent cognitive decline.

Effects of Intensive Blood Pressure Treatment on Acute Kidney Injury Events in the Systolic Blood Pressure Intervention Trial (SPRINT).

BACKGROUND: Treating to a lower blood pressure (BP) may increase acute kidney injury (AKI) events. STUDY DESIGN: Data for AKI resulting in or during hospitalization or emergency department visits were collected as part of the serious adverse events reporting process of the Systolic Blood Pressure Intervention Trial (SPRINT). SETTING & PARTICIPANTS: 9,361 participants 50 years or older with 1 or more risk factors for cardiovascular disease. INTERVENTIONS: Participants were randomly assigned to a systolic BP target of <120 (intensive arm) or <140mmHg (standard arm). OUTCOMES & MEASUREMENTS: Primary outcome was the number of adjudicated AKI events. Secondary outcomes included severity of AKI and degree of recovery of kidney function after an AKI event. Baseline creatinine concentration was defined as the most recent SPRINT outpatient creatinine value before the date of the AKI event. RESULTS: There were 179 participants with AKI events in the intensive arm and 109 in the standard arm (3.8% vs 2.3%; HR, 1.64; 95% CI, 1.30-2.10; P<0.001). Of 288 participants with an AKI event, 248 (86.1%) had a single AKI event during the trial. Based on modified KDIGO (Kidney Disease: Improving Global Outcomes) criteria for severity of AKI, the number of AKI events in the intensive versus standard arm by KDIGO stage was 128 (58.5%) versus 81 (62.8%) for AKI stage 1, 42 (19.2%) versus 18 (14.0%) for AKI stage 2, and 42 (19.2%) versus 25 (19.4%) for AKI stage 3 (P=0.5). For participants with sufficient data, complete or partial resolution of AKI was seen for 169 (90.4%) and 9 (4.8%) of 187 AKI events in the intensive arm and 86 (86.9%) and 4 (4.0%) of 99 AKI events in the standard arm, respectively. LIMITATIONS: Trial results are not generalizable to patients with diabetes mellitus or without risk factors for cardiovascular disease. CONCLUSIONS: More intensive BP lowering resulted in more frequent episodes of AKI. Most cases were mild and most participants had complete recovery of kidney function. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT01206062.

Effects of Intensive BP Control in CKD.

The appropriate target for BP in patients with CKD and hypertension remains uncertain. We report prespecified subgroup analyses of outcomes in participants with baseline CKD in the Systolic Blood Pressure Intervention Trial. We randomly assigned participants to a systolic BP target of <120 mm Hg (intensive group; n=1330) or <140 mm Hg (standard group; n=1316). After a median follow-up of 3.3 years, the primary composite cardiovascular outcome occurred in 112 intensive group and 131 standard group CKD participants (hazard ratio [HR], 0.81; 95% confidence interval [95% CI], 0.63 to 1.05). The intensive group also had a lower rate of all-cause death (HR, 0.72; 95% CI, 0.53 to 0.99). Treatment effects did not differ between participants with and without CKD (P values for interactions ≥0.30). The prespecified main kidney outcome, defined as the composite of ≥50% decrease in eGFR from baseline or ESRD, occurred in 15 intensive group and 16 standard group participants (HR, 0.90; 95% CI, 0.44 to 1.83). After the initial 6 months, the intensive group had a slightly higher rate of change in eGFR (-0.47 versus -0.32 ml/min per 1.73 m2 per year; P<0.03). The overall rate of serious adverse events did not differ between treatment groups, although some specific adverse events occurred more often in the intensive group. Thus, among patients with CKD and hypertension without diabetes, targeting an SBP<120 mm Hg compared with <140 mm Hg reduced rates of major cardiovascular events and all-cause death without evidence of effect modifications by CKD or deleterious effect on the main kidney outcome.

Association of Albuminuria and Estimated Glomerular Filtration Rate with Functional Performance Measures in Older Adults with Chronic Kidney Disease.

BACKGROUND: Chronic kidney disease (CKD) is increasingly common and disproportionately affects older adults. The contribution of kidney disease to the functional impairment noted in the elderly CKD population is unclear. METHODS: This is a cross-sectional analysis of a hypertensive cohort of people aged ≥75 years from the Systolic Blood Pressure Intervention Trial. We evaluated estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR) as predictors of 3 measures of functional status: EuroQol-5 Dimensional (EQ-5D) score, Falls Efficacy Scale (FES) score, and gait speed. Linear regression models were used to evaluate the associations between our independent variables and outcome measures. RESULTS: Our analysis included 2,620 participants, mean age of 79.9 (4.0) years. Unadjusted models showed that lower eGFR level and higher UACR level were associated with lower EQ-5D (p < 0.001 for both) and slower gait speed (p < 0.001 for both) and worse scores on FES (p = 0.032 and p = 0.039). In the fully adjusted models, higher levels of UACR remained significantly associated with lower EQ-5D scores and slower gait speed (p = 0.011 and p = 0.002, respectively). In contrast, level of eGFR was not associated with any functional outcome measures when accounting for covariates. CONCLUSIONS: In individuals aged ≥75 years, albuminuria and eGFR were associated with impairments in physical performance and self-reported functional status; however, only the association with albuminuria remained after adjusting for relevant demographics and comorbidities. Evaluation of albuminuria may provide an additional tool for identifying older individuals at risk for functional impairment.

Dialytic hemodynamics are associated with changes in gait speed.

INTRODUCTION: Functional impairment and reduced mobility are prevalent in patients on chronic hemodialysis (HD). The impact of HD on physical performance and mobility needs evaluation. METHODS: We measured gait speed in a cohort of chronic HD patients both pre and post an HD session. We collected demographic and laboratory data and dialytic hemodynamic parameters for the HD session. Participants completed the Falls Efficacy Scale International (FES-I) survey to assess concern for falling. We used linear regression analysis to tests for associations between our predictor variables of intra-dialytic hemodynamic change and change in gait speed from pre to post HD (primary outcome) and FES-I score (secondary outcome). FINDINGS: Twenty-eight participants completed the study. The mean (SD) age was 64.0 (10.5) years. The majority were male (71.4%), had hypertension (85.7%) and diabetes (57.1%). The mean (SD) change in gait speed from pre to post dialysis was -0.06 (0.08) m/s. A greater decrease in gait speed was associated with greater decrease in SBP and DBP from pre to post HD (p = 0.02 and p = 0.04, respectively) and greater maximum drop in SBP and DBP during HD (p = 0.01 and p <0.01, respectively). The association between maximum drop in SBP and DBP and gait speed remained significant after adjustment for covariates. There was no association between BP change and FES-I score. DISCUSSION: Our results suggest that HD patients who have greater decrease in BP during HD are at risk for decreased gait speed post HD.

Hemodynamics During Dialysis and Changes in Cognitive Performance.

INTRODUCTION: Hemodialysis (HD) patients are at increased risk for cognitive impairment. Blood pressure (BP) fluctuations during HD may affect cerebral perfusion and subsequently cognitive function. OBJECTIVE: Examine and provide information on the relationship between intradialytic hemodynamics and cognitive outcomes over a 1-year period. METHODS: HD patients without diagnosed dementia who were 50 years old or older were given a neurocognitive battery at baseline and at 1-year follow-up. Over the 1-year period, we collected demographic and laboratory data, as well as dialytic BP and ultrafiltration rate (UFR) measurements and tested the association between changes in cognitive test scores and intradialytic hemodynamics, adjusting for demographic and clinical variables. RESULTS: Thirty-nine participants enrolled in the study and 32 remained at 1-year follow-up. The mean (SD) age was 66.8 (10.0) years. Hypertension was present in 100% and diabetes mellitus in 47% of the cohort. The average change in systolic BP from predialysis to postdialysis was -9.9 (16.3) mmHg, and average maximum drop in systolic BP during dialysis was 27.9 (10.2) mmHg. Overall, the cognitive test scores did not have significant changes from baseline to 1 year. In our linear regression analysis there was no association between the BP measures and cognitive changes, although UFR was associated with change in performance on a test of executive functioning. CONCLUSIONS: In prevalent HD patients, cognitive function was generally stable over a 1-year period, and there was no association with intradialytic hemodynamic variables.

Risk of dementia in peritoneal dialysis patients compared with hemodialysis patients.

BACKGROUND: Compared with similarly aged controls, patients with end-stage renal disease (ESRD) have a higher prevalence of cognitive impairment and more rapid cognitive decline, which is not explained by traditional risk factors alone. Since previous small studies suggest an association of cognitive impairment with dialysis modality, we compared incident dementia among patients initiating hemodialysis (HD) vs peritoneal dialysis (PD) in a large national cohort. METHODS: This is a retrospective cohort study of incident dialysis patients in the United States from 2006 to 2008 with no diagnosis of dementia prior to beginning dialysis. We evaluated the effect of initial dialysis modality on incidence of dementia, diagnosed by Medicare claims data, adjusted for baseline demographic and clinical data from the USRDS registry. RESULTS: Our analysis included 121,623 patients, of whom 8,663 initiated dialysis on PD. The mean age of our cohort was 69.2 years. Patients who initiated PD had a lower cumulative incidence of dementia than those who initiated HD (1.0% vs 2.7%, 2.5% vs 5.3%, and 3.9% vs 7.3% at 1, 2, and 3 years, respectively). The risk of dementia for patients who started on PD was lower compared with those who started on HD, with a hazard ratio (HR) = 0.46 [0.41, 0.53], in an unadjusted model and HR 0.74 [0.64, 0.86] in a matched model. CONCLUSIONS: Dialysis modality is associated with incident dementia in a cohort of older ESRD patients. This finding warrants further investigation of the effect of dialysis modality on cognitive function and evaluation for possible mechanisms.

Haemodynamics during dialysis and cognitive performance.

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.

Hydrochlorothiazide compared to chlorthalidone in reduction of urinary calcium in patients with kidney stones.

Prevention of recurrent calcium stone disease includes treatment with thiazide and thiazide-type diuretics to reduce urinary calcium (UCa) levels, with the reduction in UCa correlating with risk of stone recurrence. There has been a recent trend of using lower doses of these medications and change from chlorthalidone (CTL) use to hydrochlorothiazide (HCTZ) use. It is unknown whether low doses of HCTZ are effective in lowering UCa levels to target levels. We hypothesize that HCTZ is associated with less reduction in UCa than is CTL when comparing currently used doses. Retrospective observational study of stone-formers was seen in metabolic stone clinic during a 3 years period. Data included patient demographics, co-morbidities, and 24 h urine electrolyte composition. Primary outcome was the change in 24 h UCa. 322 patients were identified with 112 meeting criteria and used in analysis. The majority were placed on HCTZ (n = 42) or CTL (n = 47) 25 mg QD. Patients on CTL 25 mg had a greater reduction in UCa (164 mg; 41 %) than those on HCTZ (85 mg; 21 %), p = 0.01. Neither CTL nor HCTZ at 12.5 mg QD significantly lowered UCa. There was a decrease in serum [K] of 0.5 Meq/L (p = 0.001) in patients on CTL 25 mg daily, but no significant difference in severe hypokalemia or arrhythmia compared to HCTZ. Our data show that CTL is associated with greater reduction in 24 h UCa compared to similarly dosed HCTZ.