Search

Background: Although CKD is said to increase among older adults, epidemiologic data on kidney function in people ≥70 years of age are scarce. The Berlin Initiative Study (BIS) aims to fill this gap by evaluating the CKD burden in older adults., Methods: The BIS is a prospective population-based cohort study whose participants are members of Germany's biggest insurance company. This cross-sectional analysis (i) gives a detailed baseline characterization of the participants, (ii) analyses the representativeness of the cohort's disease profile, (iii) assesses GFR and albuminuria levels across age categories, (iv) associates cardiovascular risk factors with GFR as well as albuminuria and (v) compares means of GFR values according to different estimating equations with measured GFR., Results: A total of 2069 participants (52.6% female, mean age 80.4 years) were enrolled: 26.1% were diabetic, 78.8% were on antihypertensive medication, 8.7% had experienced a stroke, 14% a myocardial infarction, 22.6% had cancer, 17.8% were anaemic and 26.5% were obese. The distribution of comorbidities in the BIS cohort was very similar to that in the insurance 'source population'. Creatinine and cystatin C as well as the albumin:creatinine ratio (ACR) increased with increasing age. After multivariate adjustments, reduced GFR and elevated ACR were associated with most cardiovascular risk factors. The prevalence of a GFR <60 mL/min/1.73 m 2 ranged from 38 to 62% depending on the estimation equation used., Conclusions: The BIS is a very well-characterized, representative cohort of older adults. Participants with an ACR ≥30 had significantly higher odds for most cardiovascular risk factors compared with an ACR <30 mg/g. Kidney function declined and ACR rose with increasing age., (© The Author 2016. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.)

Background: Continuous intradialytic bioelectrical impedance spectroscopy of the calf (cBIS) monitors changes in calf extracellular fluid volume (cECV), thus allowing estimation of hydration in end-stage renal disease patients. Blood volume monitoring (BVM) during hemodialysis (HD) provides information about relative changes in intravascular volume, which indirectly reflects plasma refilling. We hypothesize that the rate of plasma refilling changes when cBIS-determined dry weight (BIS-DW) is reached., Methods: Post-HD weight was reduced from baseline (BL) in 15 patients until dry weight was reached according to cBIS criteria (BIS-DW). The slopes of cBIS and BVM curves were analysed during the first 30 and last 20 min in 31 BL treatments, which were compared to the slopes during 31 treatments when BIS-DW was reached., Results: During BL treatments, BVM slopes did not differ between the first 30 and last 20 min (-0.112 ± 0.157%/min versus -0.089 ± 0.036, P = n.s.), while cBIS slopes were generally steeper at the beginning than at the end of HD (-0.184 ± 0.139%/min versus 0.10 ± 0.127, P < 0.01). During BIS-DW treatments, BVM and cBIS slopes were steeper at the beginning than at the end (BVM: -0.131 ± 0.122 versus -0.064 ± 0.051, P < 0.01; cBIS: -0.192 ± 0.129 versus -0.035 ± 0.012, P < 0.001) and the cBIS slopes were steeper than BVM slopes at the beginning of HD. This relationship is inverted at the end of HD, when BIS-DW is reached (beginning: -0.192 ± 0.129 versus -0.131 ± 0.122, P < 0.05, end: -0.035 ± 0.012 versus -0.064 ± 0.051, P = 0.05)., Conclusions: This study demonstrates that cECV changes faster at the beginning than at the end of HD. A reversal steepness of the cBIS slope in relation to BVM slope is observed at the time when BIS-DW is reached. Therefore, combined analysis of cBIS and BVM aiming at clinical end points may be useful to assess the relationship between plasma refilling and tissue hydration during dialysis.

Background: Hyperphosphataemia in patients with chronic kidney disease (CKD) is associated with mineral and bone disorder and increased cardiovascular mortality. Despite phosphate binders (PB), nutrition counselling and dialysis therapy, the prevalence of hyperphosphataemia remains unacceptably high. It was hypothesized that an inadequate relation of PB dose to meal inorganic phosphorus (iP) content may be an important factor for failure of phosphate management., Methods: The innovative 'Phosphate Education Program' (PEP) bases on patient empowerment to eye-estimate meal iP content by newly defined 'Phosphate Units' (PU; 1 PU per 100 mg phosphorus) and self-adjust PB dosage to dietary iP intake by an individually prescribed PB/PU ratio (PB pills per PU). In a prospective study, 16 children (aged 4-17 years) with CKD and their parents were trained with the PEP concept and followed up for 24 weeks for changes in serum electrolyte levels, dietary behaviour and PB dose., Results: Within 6 weeks after PEP training, the percentage of children with serum phosphate (PO) >1.78 mmol/l dropped from 63% (10/16) to 31% (5/16). Mean serum PO level decreased from 1.94 ± 0.23 at baseline to 1.68 ± 0.30 (SD) mmol/l in Week 7-12 (P = 0.02) and to 1.78 ± 0.36 (SD) mmol/l in Week 19-24 (P = 0.2), whereas serum calcium [2.66 ± 0.3 vs 2.60 ± 0.23 (SD) mmol/l in Weeks 7-12 (P = 0.45) and 2.66 ± 0.23 (SD) mmol/l in Week 19-24 (P = 0.21)] and serum potassium [4.69 ± 0.48 vs 4.58 ± 0.68 (SD) mmol/l in Week 7-12 (P = 0.40) and 4.65 ± 0.49 (SD) mmol/l in Week 19-24 (P = 0.73)] remained unchanged. The mean daily PB dose rose from 6.3 ± 2.9 to 8.2 ± 5.4 (SD) pills during observation period with an increased meal-to-meal variability (P = 0.04). Dietary iP intake was not affected by PEP concept., Conclusion: The empowerment of children with CKD and their parents to self-adjust PB dose to eye-estimated meal iP content significantly improved management of hyperphosphataemia without reducing dietary iP intake.

Background: Maintenance haemodialysis patients often suffer from secondary hyperparathyroidism and serum parathyroid hormone levels may be influenced by nutritional variables., Methods: We examined serum bio-intact parathyroid hormone (BiPTH) and plasma vitamin C in 117 chronic haemodialysis patients. Plasma vitamin C was measured by high-performance liquid chromatography with electrochemical detection, on samples collected before start of the dialysis treatment., Results: Plasma vitamin C showed a significant positively skewed distribution, ranging from <2 microM to >300 microM. We found 15% (n = 17) of the patients with severe vitamin C deficiency (<10 microM), 66% (n = 77) in the range 10-80 microM, and 19% (n = 23) with plasma vitamin C >80 microM, the upper limit of normal for non-renal disease population. High plasma vitamin C was associated with lower plasma BiPTH (P = 0.005, one-way analysis of variance), and this association persisted after stepwise multiple regression for other factors known to influence PTH. Low vitamin C levels were also associated with increased serum alkaline phosphatase, a further indicator of the impact of vitamin C status on bone metabolism. Patients who reported dietary vitamin C intake of >or=100 mg/day had lower BiPTH (P = 0.015), consistent with findings from plasma measurements of vitamin C. This novel observation of the interaction between PTH and vitamin C may result from effects of vitamin C on cAMP-linked signalling pathways in bone and parathyroid gland., Conclusions: This finding does not yet warrant therapeutic intervention with supplemental vitamin C to remedy secondary hyperparathyroidism. However, further research may indicate a key interaction between vitamin C and the parathyroid hormone linked signalling pathways, and may uncover mechanisms of therapeutic importance.

Background: Intravenous (IV) iron is widely prescribed for patients on haemodialysis, to replace iron losses during treatment. It releases labile iron, which can induce oxidation of vitamin C and trigger oxidant damage. We examined the stability of vitamin C in the presence of IV iron compounds. We further examined in the ability of vitamin C to release iron from these compounds., Methods: Vitamin C was measured by high-performance liquid chromatography with electrochemical detection. Iron release from iron sucrose (FeSuc) and ferric gluconate (FeGlu) was determined with the ferrozine method., Results: Vitamin C, in human plasma or fetal calf serum, was oxidized in this order of reactivity: FeSuc > FeGlu > blank reaction. FeSuc and FeGlu also oxidized vitamin C when added to freshly obtained whole human blood. During a 4 h incubation in buffer, vitamin C stimulated the release of 60% of the iron content of FeSuc at p 4, with lesser amounts at pH 3, 5 and 6, and 5% release at pH 7. Vitamin C also triggered the release of iron from FeGlu, but less release was observed than with FeSuc. Using ferrozine reagent, no iron release was detected to heparinized human plasma, following addition of 500 microM concentrations of iron compounds., Conclusion: Each IV-iron compound can oxidize substantial amounts of vitamin C when added to plasma or whole blood. The interaction of vitamin C is accompanied by release of iron from the particle at mildly acidic pH, which may explain the ability of high-dose vitamin C to mobilize iron from storage sites for erythropoiesis.

Background: Inadequate dialysis dose is closely related to mortality and morbidity of maintenance haemodialysis (MHD) patients. According to the DOQI guidelines a minimum prescribed dialysis dose of single-pool Kt/V (Kt/Vsp)=1.3, equivalent to equilibrated double pool Kt/V (e-Kt/Vdp)=1.1, is recommended. Knowledge of patient-related risk factors for inadequate delivery of hacmodialysis would be helpful to select patient subgroups for intensive control ofdialysis adequacy., Methods: A retrospective survey was conducted to assess the prevalence of inadequate dialysis dose according to DOQI criteria during a 7-month period. A total of 320 e-Kt/Vdp measurements in 62 MHD patients were evaluated (mean effective dialysis time 222+/-32 min). Residual renal function (RRF) was expressed as renal weekly Kt/V (r-Kt/Vweek) and included into assessment of total weekly renal and dialytic Kt/V (t-Kt/Vweek)., Results: Inadequacy (e-Kt/Vdp<1.10) was prevalent in 37.2% of all measurements and in 22/62 patients (35.5%). In 54% of underdialysed patients r-Kt/Vweek compensated for insufficient dialytic urea removal. Mean weekly Kt/V was inadequate (t-Kt/Vweek<3.30) in 12/62 patients (19.4%) of whom 91.7% (11/12) were male. Body-weight, urea distribution volume (UDV). and body-surface area (BSA) were significantly higher in inadequately is adequately dialysed males. UDV>42.0 litres or BSA>2.0 m2 and a lack of RRF (r-Kt/Vweek<0.3) put 'big men' at increased risk to receive an inadequate dose of dialysis., Conclusion: Our data identify patients at risk for inadequate haemodialysis treatment. Special attention should be focused on 'big men' with UDV>42.0 litres or BSA>2.0 m2. In this subset of patients frequent measurements of t-Kt/Vweek and assessment of RRF should be mandatory.