The prevalence, severity, and association with HbA1c and fibrinogen of cognitive impairment in chronic kidney disease.

Cognitive impairment is a frequent finding in patients with chronic kidney disease (CKD). We examined cognitive performance in a prospective study of 119 patients with CKD stages 3-5 (including dialysis) and 54 control patients of the same age without CKD but with similar vascular risk profiles. Analysis included a comprehensive test battery evaluating memory, information processing speed, executive function, language, and visuoconstructive function, in addition to depression and anxiety. Thirty percent of patients with CKD had cognitive deficits (one or more s.d. below control patient performance). Cognitive deficits (T-value related to published norm values) were mild but significantly decreased to 48.8 in patients with stage 3-5 CKD not requiring hemodialysis and 47.2 in patients with stage 5D disease requiring hemodialysis, compared with 51.5 in control patients. Linear regressions among patients with CKD (forced entry strategy) showed that age (ß=-0.50 per s.d.), HbA1c (ß=-0.18 per s.d.), and fibrinogen (ß=-0.18 per s.d.) predicted cognitive performance. Interestingly, HbA1c discriminated cognition in all age groups, while fibrinogen differentiated cognition particularly in patients over 70 years of age. Thus, our cross-sectional study suggests the severity of cognitive impairment in CKD is mild. As such, longitudinal studies are required to further characterize the role of cognitive deficits in CKD.

Relationship between magnesium and clinical biomarkers on inhibition of vascular calcification.

BACKGROUND: Arteriosclerosis and cardiovascular disease are strongly associated with vascular calcification. Hyperphosphatemia is an essential risk factor for increased vascular calcification. End-stage renal disease (ESRD) patients could serve as an in vivo model for accelerated calcification. This study focuses on the most likely protective effects of magnesium ion (Mg(2+)) on phosphate-induced vascular calcification ex vivo/in vitro. Furthermore, plasma Mg(2+) concentrations of ESRD and healthy controls were investigated for association with surrogate parameters of vascular calcification in vivo. METHODS: Aortic segments of male Wistar-Kyoto rats were incubated and the phosphate concentration of the medium was elevated. The aortic segments were incubated in the absence and presence of MgCl(2); tissue calcification was quantified by different methods. Serum Mg(2+) concentrations of patients with chronic kidney disease (CKD stage 5; ESRD) and patients without CKD (controls) were associated with carotid intima media thickness (IMT) and aortic pulse wave velocity (PWV) as surrogate parameter for arteriosclerosis and arterial stiffening. RESULTS: Incubation of aortic segments in the presence of ß-glycerophosphate and NaH(2)PO(4) caused an increased tissue Ca(2+) deposition compared to control conditions. This increased amount of Ca(2+) in the aortic rings was significantly decreased in the presence of Mg(2+). In CKD patients, but not in controls, magnesium serum concentration was associated with the IMT of the carotid arteries. In addition, CKD patients with higher magnesium serum concentration had a significantly lower PWV. DISCUSSION AND CONCLUSION: Elevated phosphate concentrations in the culture media induce ex vivo/in vitro medial calcification in intact rat aortic rings in the presence of alkaline phosphatase. Mg(2+) ions reduced ex vivo/in vitro vascular calcification despite increased phosphate concentration. This hypothesis is additionally based on the fact that CKD patients with high Mg(2) serum levels had significantly lower IMT and PWV values, which may result in a lower risk for cardiovascular events and mortality in these patients. Therefore, Mg(2+) supplementation may be an option for treatment and prevention of vascular calcification resulting in a reduction of cardiovascular events in CKD patients.

Iterative cardiac output measurement for optimizing cardiac resynchronization therapy: a randomized, blinded, crossover study.

BACKGROUND: Many invasive and noninvasive methods have been proposed for guiding optimal programming of cardiac resynchronization therapy (CRT) devices. However, results are not satisfying. Preliminary results suggest that cardiac output (CO) measurements using inert gas rebreathing (IGR) might be an eligible method to tailor atrioventricular (AV) and ventriculo-ventricular (VV) programming. The aims of the present study were: (1) to evaluate whether an optimization of CRT can be obtained by noninvasive CO measurements and (2) to evaluate whether acute hemodynamic improvements obtained by this approach relate into increase in cardiac exercise capacity. METHODS: In 24 patients on CRT, iterative VV- and AV-delay optimization was done using the IGR method. This blinded, randomized, crossover study compared the responses to optimization during two periods: a 4-week optimized and a 4-week standard programming. Exercise capacity after optimization was assessed after each period by New York Heart Association (NYHA) classification, a 6-minute walking test, and quality of life (QoL) questionnaire. RESULTS: CO could be determined by IGR in all patients. The NYHA class decreased by 17.8% (2.8 ± 0.3 vs 2.3 ± 0.4, P < 0.001), the mean (± standard deviation) distance walked in 6 minutes was 9.3% greater after optimization (456 ± 140 m vs 417 ± 134 m, P < 0.001), and the QoL improved by 14.5% (41.8 ± 10.4 vs 36.5 ± 9.5, P < 0.001). The portion of responders to CRT increased from 66.5% to 87.5%. CONCLUSION: CRT optimization by iterative CO measurements leads to an increase in CO and an improvement of exercise capacity. Our results suggest that this method might become an important additive tool to adjust CRT programming.

Cognitive Performance Is Highly Stable over a 2-Year-Follow-Up in Chronic Kidney Disease Patients in a Dedicated Medical Environment.

BACKGROUND: As kidney and brain functions decline with aging, chronic kidney disease (CKD) and dementia are becoming increasing health burdens worldwide. Among the risk factors for cognitive impairment, CKD is increasingly recognized. The precise impact of CKD on the development of cognitive impairment is poorly understood. METHODS: In the New Tools for the Prevention of Cardiovascular Disease in Chronic Kidney Disease (NTCVD) cohort, which was recruited in a dedicated nephrology department, we examined the 2-year course of cognitive performance in 120 patients (73 patients with CKD stages 3-5D, 47 control patients without CKD with similar vascular risk profile) using a comprehensive battery of 10 neuropsychological tests. RESULTS: Kidney function, vascular risk factors and cognitive performance were highly stable both in CKD and control patients. The summary score of cognitive performance in CKD patients was very similar at baseline (z = -0.63±0.76) and follow-up (z = -0.54±0.79, p = 0.113), as was cognitive performance in control patients (z = -0.01±0.59 and 0.01±0.70, p = 0.862, at baseline and follow-up, respectively). Total serum cholesterol (199.6±36.0 and 186.0±32.9, p = 0.005 in controls; 194.4±46.1 and 181.2±41.2, p = 0.008 in CKD) and common carotid intima-media thickness (0.87±0.18 and 0.84±0.17, p = 0.351 in controls; 0.88±0.21 and 0.82±0.16, p = 0.002 in CKD) moderately but significantly decreased during the follow-up. In multivariable regression analyses, high age (ß = -0.28, 95%CI = -0.48 to 0.08, p = 0.007) predicted decrease in cognitive performance. CONCLUSIONS: In this well-defined cohort receiving state-of-the-art therapy, cognitive performance did not decrease over 2 years. Our data emphasize the aspect of risk factor control, suggesting that dedicated medical care might prevent cognitive decline in CKD patients.

Factors Responsible for Plasma ß-Amyloid Accumulation in Chronic Kidney Disease.

Disturbed brain-to-blood elimination of ß-amyloid (Aß) promotes cerebral Aß accumulation in Alzheimer's disease. Considering that the kidneys are involved in Aß elimination from the blood, we evaluated how chronic kidney disease (CKD) affects plasma Aß. In 106 CKD patients stages 3-5 (including 19 patients on hemodialysis and 15 kidney recipients), 53 control subjects with comparable vascular risk profile and 10 kidney donors, plasma Aß was determined using electrochemiluminescence immunoassay and gel electrophoresis followed by Western blotting. Plasma Aß increased with CKD stage (control = 182.98 ± 76.73 pg/ml; CKD3A = 248.34 ± 103.77 pg/ml; CKD3B = 259.25 ± 97.74 pg/ml; CKD4 = 489.16 ± 154.16 pg/ml; CKD5 = 721.19 ± 291.69 pg/ml) and was not influenced by hemodialysis (CKD5D = 697.97 ± 265.91 pg/ml). Renal transplantation reduced plasma Aß (332.57 ± 162.82 pg/ml), whereas kidney donation increased it (251.51 ± 34.34 pg/ml). Gel electrophoresis confirmed stage-dependent elevation namely of Aß1-40, the most abundant Aß peptide. In a multivariable regression including age, sex, estimated glomerular filtration rate (eGFR), potassium, hemoglobin, urine urea, and urine total protein, the factors eGFR (ß = -0.42, p < 0.001), hemoglobin (ß = -0.17, p = 0.020), and urine protein (ß = 0.26, p = 0.008) were associated with plasma Aß. In a regression including age, sex, eGFR, potassium, hemoglobin and the vascular risk factors systolic blood pressure, smoking, LDL, HDL, HbA1c, body mass index, brain-derived natriuretic peptide and fibrinogen, the factors eGFR (ß = -0.53, p < 0.001), body mass index (ß = -0.17, p = 0.022), and fibrinogen (ß = 0.18, p = 0.024) were associated with plasma Aß. Our results demonstrate a stage-dependent plasma Aß increase that is augmented by loss of glomerulotubular integrity, low body weight, and inflammation, demonstrating a multifaceted role of renal dysfunction in Aß retention.

Physical, cognitive and emotional factors contributing to quality of life, functional health and participation in community dwelling in chronic kidney disease.

BACKGROUND: Quality of life (QoL) impairment is a well-known consequence of chronic kidney disease (CKD). The factors influencing QoL and late life functional health are poorly examined. METHODS: Using questionnaires combined with neuropsychological examinations, we prospectively evaluated physical, cognitive, and emotional factors influencing QoL, functional health and participation in community dwelling in 119 patients with CKD stages 3-5 including hemodialysis (61.5±15.7years; 63% men) and 54 control patients of the same age without CKD but with similar cardiovascular risk profile. RESULTS: Compared with control patients, CKD patients showed impairment of the physical component of QoL and overall function, assessed by the SF-36 and LLFDI, whereas disability, assessed by LLFDI, was selectively impaired in CKD patients on hemodialysis. Multivariable linear regressions (forced entry) confirmed earlier findings that CKD stage (ß = -0.24; p = 0.012) and depression (ß = -0.30; p = 0.009) predicted the QoL physical component. Hitherto unknown, CKD stage (ß = -0.23; p = 0.007), cognition (ß = 0.20; p = 0.018), and depression (ß = -0.51; <0.001) predicted disability assessed by the LLFDI, while age (ß = -0.20; p = 0.023), male gender (B = 5.01; p = 0.004), CKD stage (ß = -0.23; p = 0.005), stroke history (B = -9.00; p = 0.034), and depression (ß = -0.41; p<0.001) predicted overall function. Interestingly, functional health deficits, cognitive disturbances, depression, and anxiety were evident almost only in CKD patients with coronary heart disease (found in 34.2% of CKD patients). The physical component of QoL and functional health decreased with age and depressive symptoms, and increased with cognitive abilities. CONCLUSIONS: In CKD, QoL, functional health, and participation in community dwelling are influenced by physical, cognitive, and emotional factors, most prominently in coronary heart disease patients.