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Rationale & objectiveThe clearance of protein-bound solutes by the proximal tubules is an innate kidney mechanism for removing putative uremic toxins that could exert cardiovascular toxicity in humans. However, potential associations between impaired kidney clearances of secretory solutes and cardiovascular events among patients with chronic kidney disease (CKD) remains uncertain.Study designA multicenter, prospective, cohort study.Setting & participantsWe evaluated 3,407 participants from the Chronic Renal Insufficiency Cohort (CRIC) study.ExposuresBaseline kidney clearances of 8 secretory solutes. We measured concentrations of secretory solutes in plasma and paired 24-hour urine specimens using liquid chromatography-tandem mass spectrometry (LC-MS/MS).OutcomesIncident heart failure, myocardial infarction, and stroke events.Analytical approachWe used Cox regression to evaluate associations of baseline secretory solute clearances with incident study outcomes adjusting for estimated GFR (eGFR) and other confounders.ResultsParticipants had a mean age of 56 years; 45% were women; 41% were Black; and the median estimated glomerular filtration rate (eGFR) was 43 mL/min/1.73 m2. Lower 24-hour kidney clearance of secretory solutes were associated with incident heart failure and myocardial infarction but not incident stroke over long-term follow-up after controlling for demographics and traditional risk factors. However, these associations were attenuated and not statistically significant after adjustment for eGFR.LimitationsExclusion of patients with severely reduced eGFR at baseline; measurement variability in secretory solutes clearances.ConclusionsIn a national cohort study of CKD, no clinically or statistically relevant associations were observed between the kidney clearances of endogenous secretory solutes and incident heart failure, myocardial infarction, or stroke after adjustment for eGFR. These findings suggest that tubular secretory clearance provides little additional information about the development of cardiovascular disease events beyond glomerular measures of GFR and albuminuria among patients with mild-to-moderate CKD.

Background We tested associations of cardiac biomarkers of myocardial stretch, injury, inflammation, and fibrosis with the risk of incident atrial fibrillation (AF) in a prospective study of chronic kidney disease patients. Methods and Results The study sample was 3053 participants with chronic kidney disease in the multicenter CRIC (Chronic Renal Insufficiency Cohort) study who were not identified as having AF at baseline. Cardiac biomarkers, measured at baseline, were NT-proBNP (N-terminal pro-B-type natriuretic peptide), high-sensitivity troponin T, galectin-3, growth differentiation factor-15, and soluble ST-2. Incident AF ("AF event") was defined as a hospitalization for AF. During a median follow-up of 8 years, 279 (9%) participants developed a new AF event. In adjusted models, higher baseline log-transformed NT-proBNP (N-terminal pro-B-type natriuretic peptide) was associated with incident AF (adjusted hazard ratio [HR] per SD higher concentration: 2.11; 95% CI, 1.75, 2.55), as was log-high-sensitivity troponin T (HR 1.42; 95% CI, 1.20, 1.68). These associations showed a dose-response relationship in categorical analyses. Although log-soluble ST-2 was associated with AF risk in continuous models (HR per SD higher concentration 1.35; 95% CI, 1.16, 1.58), this association was not consistent in categorical analyses. Log-galectin-3 (HR 1.05; 95% CI, 0.91, 1.22) and log-growth differentiation factor-15 (HR 1.16; 95% CI, 0.96, 1.40) were not significantly associated with incident AF. Conclusions We found strong associations between higher NT-proBNP (N-terminal pro-B-type natriuretic peptide) and high-sensitivity troponin T concentrations, and the risk of incident AF in a large cohort of participants with chronic kidney disease. Increased atrial myocardial stretch and myocardial cell injury may be implicated in the high burden of AF in patients with chronic kidney disease.

BackgroundRetinal microvascular abnormalities have been associated with cognitive impairment, possibly serving as a marker of cerebral small-vessel disease. This relationship has not been evaluated in persons with chronic kidney disease (CKD), a condition associated with increased risk of both retinal pathology and cognitive impairment.Study designCross-sectional study.Setting & participants588 participants 52 years or older with CKD in the Chronic Renal Insufficiency Cohort (CRIC) Study.PredictorRetinopathy graded using the Early Treatment Diabetic Retinopathy Study severity scale and diameters of retinal vessels.OutcomesNeuropsychological battery of 6 cognitive tests.MeasurementsLogistic regression models were used to evaluate the association of retinopathy, individual retinopathy features, and retinal vessel diameters with cognitive impairment (≤1 SD from the mean), and linear regression models were used to compare cognitive test scores across levels of retinopathy, adjusting for age, race, sex, education, and medical comorbid conditions.ResultsThe mean age of the cohort was 65.3±5.6 (SD) years, 51.9% were nonwhite, and 52.6% were men. The prevalence of retinopathy was 30.1%, and the prevalence of cognitive impairment was 14.3%. Compared with those without retinopathy, participants with retinopathy had an increased likelihood of cognitive impairment on executive function (35.1% vs 11.5%; OR, 3.4 [95% CI, 2.0-6.0]), attention (26.7% vs 7.3%; OR, 3.0 [95% CI, 1.8-4.9]), and naming (26.0% vs 10.0%; OR, 2.1 [95% CI, 1.2-3.4]) after multivariable adjustment. Increased level of retinopathy also was associated with lower cognitive performance on executive function and attention. Microaneurysms were associated with cognitive impairment on some domains, but there were no significant associations with other retinal measures after multivariable adjustment.LimitationsUnknown temporal relationship between retinopathy and impairment.ConclusionsIn adults with CKD, retinopathy is associated with poor performance on several cognitive domains, including executive function and attention. Evaluation of retinal microvascular abnormalities may be a promising tool for identifying patients with CKD who are at increased risk of cognitive impairment.

Vitamin K is linked to cognitive function, but studies in individuals with chronic kidney disease (CKD), who are at risk for vitamin K insufficiency and cognitive impairment, are lacking. The cross-sectional association of vitamin K status biomarkers with cognitive performance was evaluated in ≥55-y-old adults with CKD (N  = 714, 49% female, 44% black). A composite score of a cognitive performance test battery, calculated by averaging the z scores of the individual tests, was the primary outcome. Vitamin K status was measured using plasma phylloquinone and dephospho-uncarboxylated matrix Gla protein [(dp)ucMGP]. Participants with low plasma (dp)ucMGP, reflecting higher vitamin K status, had better cognitive performance than those in the two higher (dp)ucMGP categories based on the composite outcome (P  = 0.03), whereas it did not significantly differ according to plasma phylloquinone categories (P  = 0.08). Neither biomarker was significantly associated with performance on individual tests (all P  > 0.05). The importance of vitamin K to cognitive performance in adults with CKD remains to be clarified. [ABSTRACT FROM AUTHOR]

Background: Heart failure (HF) is a leading contributor to cardiovascular morbidity and mortality in the population with chronic kidney disease (CKD). HF risk prediction tools that use readily available clinical parameters to risk-stratify individuals with CKD are needed.Methods: We included Black and White participants aged 30-79 years with CKD stages 2-4 who were enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study and were without self-reported cardiovascular disease. We assessed model performance of the Pooled Cohort Equations to Prevent Heart Failure (PCP-HF) to predict incident hospitalizations due to HF and refit the PCP-HF in the population with CKD by using CRIC data-derived coefficients and survival from CRIC study participants in the CKD population (PCP-HFCKD). We investigated the improvement in HF prediction with inclusion of estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR) into the PCP-HFCKD equations by change in C-statistic, net reclassification improvement (NRI), and integrated discrimination improvement index (IDI). We validated the PCP-HFCKD with and without eGFR and UACR in Multi-Ethnic Study of Atherosclerosis (MESA) participants with CKD.Results: Among 2328 CRIC Study participants, 340 incident HF hospitalizations occurred over a mean follow-up of 9.5 years. The PCP-HF equations did not perform well in most participants with CKD and had inadequate discrimination and insufficient calibration (C-statistic 0.64-0.71, Greenwood-Nam-D'Agostino (GND) chi-square statistic P value < 0.05), with modest improvement and good calibration after being refit (PCP-HFCKD: C-statistic 0.61-0.78), GND chi-square statistic P value > 0.05). Addition of UACR, but not eGFR, to the refit PCP-HFCKD improved model performance in all race-sex groups (C-statistic [0.73-0.81], GND chi-square statistic P value > 0.05, delta C-statistic ranging from 0.03-0.11 and NRI and IDI P values < 0.01). External validation of the PCP-HFCKD in MESA demonstrated good discrimination and calibration.Conclusions: Routinely available clinical data that include UACR in patients with CKD can reliably identify individuals at risk of HF hospitalizations. [ABSTRACT FROM AUTHOR]

Background Among patients with chronic kidney disease (CKD), the circulating cardiac biomarkers soluble ST2 (SST2), galectin-3, growth differentiation factor-15 (GDF-15), N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin-T (hsTnT) possibly reflect pathophysiologic processes and are associated with clinical cardiovascular disease. Whether these biomarkers are associated with electrocardiographic findings is not known. The aim of this study was to test the association between serum cardiac biomarkers and the presence of electrocardiographic changes potentially indicative of subclinical myocardial disease in patients with CKD. Methods We performed a cross-sectional analysis using 3048 participants from the Chronic Renal Insufficiency Cohort (CRIC) without atrial fibrillation, atrioventricular block, bundle branch block or a pacemaker at the baseline visit. Using logistic regression, we tested the association of each of the five cardiac biomarkers with baseline electrocardiogram (ECG) findings: PR interval >200 ms, QRS interval >100 ms and a prolonged QTc interval. Models were adjusted for demographic variables, measures of kidney function, prevalent cardiovascular disease and cardiovascular risk factors. Results In adjusted models, hsTnT levels associated with prolonged PR {odds ratio [OR] 1.23 [95% confidence interval (CI) 1.08–1.40]}, QRS [OR 1.28 (95% CI 1.16–1.42)] and QTc [OR 1.94 (95% CI 1.50–2.51)] intervals. NT-proBNP levels were associated with prolonged QRS [OR 1.11 (95% CI 1.06–1.16)] and QTc [OR 1.82 (95% CI 1.58–2.10)] intervals. SST2, galectin-3 and GDF-15 were not significantly associated with any of the ECG parameters. Conclusions hsTnT and NT-proBNP were associated with ECG measures indicative of subclinical myocardial dysfunction. These results may support future research investigating the significance of myocardial ischemia and volume overload in the pathogenesis of dysfunctional myocardial conduction in CKD. [ABSTRACT FROM AUTHOR]

Background: Chronic kidney disease (CKD) is a significant risk factor for cognitive impairment. Previous studies have examined differences in cognitive impairment between persons with and without CKD using multiple cognitive outcomes, but few have done this for an extensive battery of cognitive tests. We relate early-stage CKD to two indices of impairment for 22 measures of cognitive ability. Methods: The study was community-based and cross-sectional with 898 individuals free from dementia and end-stage renal disease. Estimated glomerular filtration rate (eGFR) was calculated using the chronic kidney disease epidemiology collaboration equation and classified as <60 or ⩾60 mL/min/1.73 m2 , based on consensus definitions of Stage 3 or greater CKD. The eGFR classifications were related to modest [⩾1 standard deviation (SD) below the mean] and severe (⩾1.5 SD below the mean) impairment on each measure using logistic regression analyses adjusting for potential risk factors. Results: A total of 146 individuals (16.3%) had eGFR <60 mL/ min/1.73m2 (mean 51±10.1 mL/min/1.73m2 ). These participants had significantly greater risk for modestly impaired abilities in the scanning and tracking and visual-spatial organization/ memory (VSOM) domains after accounting for comorbidity-related risk factors [odds ratios (ORs) between 1.68 and 2.16], as well as greater risk for severely impaired functioning in the language domain (OR = 2.65). Conclusions: Participants with eGFR <60 mL/min/1.73 m2 were at higher risk for cognitive impairment than those with eGFR ⩾60 mL/min/1.73 m2 on the majority of cognitive abilities, specifically those within the VSOM, Language, and scanning and tracking domains. Targeted screening for cognitive deficits in kidney disease patients early in their disease course may be warranted. [ABSTRACT FROM AUTHOR]

It is well known that the population with chronic kidney disease (CKD) is at greater risk for cardiovascular disease and death than the general population. The use and interpretation of high sensitivity cardiac troponin (hs-cTn) assays have been particularly challenging in these patients with the majority having elevated levels at baseline. The diagnostic accuracy of acute myocardial infarction (AMI) may be decreased in patients with CKD when using these newer troponins. In order to improve the sensitivity and specificity for the diagnosis of AMI, one must look at the change in cTn and consider using higher cut-off values. In asymptomatic patients with CKD, research has shown increased prevalence of cardiovascular risk factors and underlying structural heart disease with increasing cTn levels. Prognostically, elevated cTn has been associated with adverse outcomes including incident heart failure and cardiovascular mortality. The purpose of the review is to evaluate hs-cTn in patients with CKD for the diagnosis of AMI and for the prognostic significance of elevated levels in CKD patients without AMI. Although the underlying etiology of persistently elevated cTn in the CKD population remains unclear, the review will also evaluate studies attempting to explain whether the source of cTn is from increased cardiac production versus decreased renal clearance. Further longitudinal studies are required in order to bridge the gap between the prognostic importance of elevated cTn and clinical management to prevent symptomatic cardiac disease. [ABSTRACT FROM AUTHOR]

Background: Leukocytosis is a powerful predictor of incident chronic kidney disease (CKD) and related outcomes. However, the association between periodontitis measures and increased leukocytosis in the context of CKD has not been well described. We sought to identify which individual measures of periodontal disease may best associate with reduced estimated glomerular filtration rate (eGFR) and albuminuria, and to test if these measures were associated with increased leukocytosis in subjects with established CKD. Methods: We estimated, among 13,270 participants in the National Health and Nutrition Examination Survey III study, the associations between case-based definition of periodontitis, clinical attachment loss (CAL) and pocket depth (PD) as individual measures of periodontal disease, with renal function measures and leukocytosis. Results: In adjusted multivariate analyses, case-based definition of severe periodontitis was associated with albuminuria (β = 0.003, p = 0.01) but not with eGFR. However, CAL and PD were all individually associated with both albuminuria (β = 0.08, p < 0.001 and β = 0.06, p < 0.001, respectively) and eGFR (β = -0.05, p < 0.001 and β = -0.03, p < 0.001, respectively). We found significant associations between elevated CAL and PD with leukocytosis. Lastly, we found a marked association between the joint presence of CKD and elevated CAL or PD with leukocytosis (odds ratio (OR) 3.3, 95% confidence interval (CI) 1.4-7.5 and OR 3.2, 95% CI 1.1-9.7, respectively). Conclusion: Individual measures of periodontal disease are associated with renal function and heightened leukocytosis in CKD subjects. The significantly added inflammatory burden noted in CKD subjects with periodontal disease argue for targeting periodontitis treatment as part of our multifaceted approach to CKD patients. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background Decreased estimated glomerular filtration rate (eGFR) and higher serum creatinine (sCR) levels have been associated with longitudinal decline in global mental status measures. Longitudinal data describing change in multiple domains of cognitive functioning are needed in order to determine which specific abilities are most affected in individuals with impaired renal function. Methods We conducted a 5-year longitudinal study with 590 community-living individuals (mean age 62.1 years, 60.2% female, 93.2% white, 11.4% with diabetes mellitus, mean eGFR 78.4 mL/min/1.73 m²) free from dementia, acute stroke and end-stage renal disease. To measure longitudinal change-over-time, cognitive performance measures were regressed on eGFR adjusting for baseline eGFR and cognitive performance, comorbidity and vascular risk factors. Outcome measures were scores from 17 separate tests of cognitive abilities that were used to index 5 theoretically relevant domains: verbal episodic memory, visual-spatial organization and memory, scanning and tracking, working memory and similarities (abstract reasoning). Results Declines in eGFR values were associated with cognitive declines, when adjusted for eGFR and cognitive function scores at baseline. Change in renal functioning over time was related to change observed in global cognitive ability [b = 0.21SD decline per unit ln(eGFR), 95% CI: 0.04–0.38, P = .018], verbal episodic memory [b = 0.28 SD decline per unit ln(eGFR), 95% CI: 0.02–0.54, P = 0.038] and abstract reasoning [b = 0.36 SD decline per unit ln(eGFR), 95% CI: 0.04–0.67, P = 0.025]. Decline in cognitive functioning in association with declining renal functioning was observed despite statistical adjustment for demographic variables and CVD risk factors and the exclusion of persons with dementia or a history of acute stroke. Conclusions Early detection of mild to moderate kidney disease is an important public health concern with regard to cognitive decline. [ABSTRACT FROM AUTHOR]

Erythropoiesis-stimulating agents (ESAs) are effective in ameliorating anemia in chronic kidney disease (CKD). A recent trial in diabetic patients with CKD, however, suggested a greater risk of stroke associated with full correction of anemia with ESAs. Using national Veterans Affairs data we performed a case-control study examining the association of incident ESA use with acute stroke in patients with estimated glomerular filtration rate <60 cm3/min per 1.73 m2 and outpatient hemoglobin <12 g/dl. Using diagnosis codes, we identified 2071 acute hospitalized stroke cases and matched them 1:5 with controls without stroke, resulting in 12,426 total patients for analysis. Conditional logistic regression was used to estimate the association of ESA use with stroke, adjusting for potential confounders. After multivariate adjustment, ESA use in 1026 patients was associated with greater odds of stroke (odds ratio 1.30). There was significant interaction between ESA use and cancer, with greater odds of stroke among ESA-treated cancer patients (odds ratio 1.85), but not in ESA-treated patients without cancer (odds ratio 1.07). ESA-treated patients with cancer received a median initial dose 2.5-4 times greater than ESA-treated patients without cancer, but pre-ESA hemoglobin and its rate of change did not differ between these groups. Hence, in a large national sample of anemic patients with CKD, ESA treatment was associated with an increased risk of acute stroke with the greatest effect among patients with cancer. [ABSTRACT FROM AUTHOR]

Background. Erythropoiesis-stimulating agents (ESAs) are frequently used to treat anaemia of chronic kidney disease (CKD) in the dialysis setting; however, few data are available regarding factors influencing initiation of ESAs and other therapies in non-dialysis patients. [ABSTRACT FROM PUBLISHER]

OBJECTIVES: To investigate cognitive impairment in older, ethnically diverse individuals with a broad range of kidney function, to evaluate a spectrum of cognitive domains, and to determine whether the relationship between chronic kidney disease (CKD) and cognitive function is independent of demographic and clinical factors. DESIGN: Cross-sectional. SETTING: Chronic Renal Insufficiency Cohort Study. PARTICIPANTS: Eight hundred twenty-five adults aged 55 and older with CKD. MEASUREMENTS: Estimated glomerular filtration rate (eGFR, mL/min per 1.73 m2) was estimated using the four-variable Modification of Diet in Renal Disease equation. Cognitive scores on six cognitive tests were compared across eGFR strata using linear regression; multivariable logistic regression was used to examine level of CKD and clinically significant cognitive impairment (score ≤1 standard deviations from the mean). RESULTS: Mean age of the participants was 64.9, 50.4% were male, and 44.5% were black. After multivariable adjustment, participants with lower eGFR had lower cognitive scores on most cognitive domains ( P<.05). In addition, participants with advanced CKD (eGFR<30) were more likely to have clinically significant cognitive impairment on global cognition (adjusted odds ratio (AOR) 2.0, 95% CI=1.1–3.9), naming (AOR=1.9, 95% CI=1.0–3.3), attention (AOR=2.4, 95% CI=1.3–4.5), executive function (AOR=2.5, 95% CI=1.9–4.4), and delayed memory (AOR=1.5, 95% CI=0.9–2.6) but not on category fluency (AOR=1.1, 95% CI=0.6–2.0) than those with mild to moderate CKD (eGFR 45–59). CONCLUSION: In older adults with CKD, lower level of kidney function was associated with lower cognitive function on most domains. These results suggest that older patients with advanced CKD should be screened for cognitive impairment. [ABSTRACT FROM AUTHOR]