Relationship Between Dietary Phosphate Intake and Biomarkers of Bone and Mineral Metabolism in Australian Adults With Chronic Kidney Disease.

OBJECTIVE: Higher serum phosphate is associated with increased adverse outcomes including cardiovascular disease. Abnormalities of bone and mineral metabolism in chronic kidney disease (CKD), including higher serum phosphate, are important risk factors for increased cardiovascular disease. Associations between dietary phosphate intake and biochemical and cardiovascular parameters in non-dialysis CKD patients, however, have not been adequately studied. This study aimed to explore associations between phosphate intake and biomarkers of bone and mineral metabolism and intermediate cardiovascular markers in adults with stage 3-4 CKD. DESIGN AND METHODS: One hundred thirty-two participants enrolled in the IMpact of Phosphate Reduction On Vascular End-points in Chronic Kidney Disease trial were invited to participate in this sub-study. At baseline, dietary phosphate intake and its source (animal, plant, or a mixture of animal and plant) were determined using a 7-day self-administered diet food record, and measurements were made of serum and urinary phosphate, serum calcium, parathyroid hormone, fibroblast growth factor-23, and the intermediate cardiovascular markers pulse wave velocity (PWV) and abdominal aortic calcification. The relationships between dietary phosphate intake and these bone metabolism and cardiovascular markers were explored using Pearson's correlation and linear regression. The effect of source of phosphate intake was analyzed using compositional data analysis. RESULTS: Ninety participants (age 64 ± 12 years, 68% male, estimated glomerular filtration rate 26.6 ± 7.6 mL/min/1.73 m2, daily phosphate intake 1,544 ± 347 mg) completed the study. Correlations among dietary phosphate intake and biochemical measures, PWV, and abdominal aortic calcification ranged from r = -0.13 to r = +0.13. Linear regression showed no association between dietary phosphate measurements and biochemical or cardiovascular parameters. Source of phosphate intake was associated with PWV (P = .01), but not with other biomarkers of bone and mineral metabolism. Higher PWV values were associated with higher intake of plant-based relative to animal-based phosphate (1.058 [1.020-1.098], P = .003). CONCLUSION: Levels of total dietary phosphate intake measured by dietary food record show no statistically significant relationship with biochemical markers of bone and mineral metabolism or intermediate cardiovascular markers. Higher PWV levels associated with higher intake of plant-based relative to animal-based phosphate intake were an unexpected finding and further research is needed in this area.

Optimizing vancomycin dosage regimens in relation to high-flux haemodialysis.

Objectives: To develop a population pharmacokinetic (PK) model for vancomycin in adults receiving high-flux haemodialysis (HFHD) in an effort to optimize vancomycin dosing in this population. Methods: A population PK model using NONMEM was developed using retrospective data collected from 48 vancomycin courses administered to patients (n = 37) receiving HFHD. Fixed-dose [1.5 g loading dose (LD), 1 g maintenance dose (MD)], literature-adapted weight-based (WBL; 20 mg/kg LD, 10 mg/kg MD) and hospital-adapted weight-based (WBH; 25-30 mg/kg LD, 20-25 mg/kg MD) dosage regimens were then simulated using the Monte Carlo method. The PTA was an AUC24/MIC ≥400 with success being a PTA ≥90%. Results: The data were best described using a two-compartment model. It was observed that fixed-dose and WBL dosage regimens resulted in a PTA ≤90% for most days. The WBH dosing achieved a PTA ≥90% on most days, but there were supratherapeutic concentrations with repeated dosing of vancomycin. If HFHD was delayed by 48-72 h after the LD, the PTA would fall below 90%. A dose-optimized regimen was developed: 30 mg/kg LD and 10 mg/kg MD given on HFHD days. An additional dose of 500 mg or 1 g was administered 24 h after the LD if HFHD occurred 48-72 h post-LD. This dose-optimized regimen afforded a PTA ≥90% on all days of therapy and achieved clinically acceptable pre-haemodialysis concentrations. Conclusions: Current vancomycin dosage regimens used clinically do not achieve a PTA ≥90% for most days of therapy for people receiving HFHD. A dose-optimized regimen was developed, which could be implemented in clinical practice.

Carvedilol and Cardiac Biomarkers in Dialysis Patients: Secondary Analysis of a Randomized Controlled Trial.

BACKGROUND/AIMS: Cardiac biomarkers are associated with cardiac abnormalities and adverse outcomes in dialysis patients. Our aim was to report the effect of the beta-blocker carvedilol on cardiac biomarkers in adult dialysis patients. METHODS: The Beta-Blocker to Lower Cardiovascular Dialysis Events Feasibility Study was a randomized controlled trial comparing carvedilol to placebo. Serum and plasma were collected before the run-in, then 6 and 12 months post-randomization to measure B-type Natriuretic Peptide (BNP), N-terminal BNP (NT-ProBNP), high-sensitivity cardiac troponins I (hs-TnI) and T (hs-TnT), and galectin-3. Left ventricular global longitudinal strain (GLS) was measured by echocardiography at baseline. RESULTS: Seventy-two participants were recruited of whom 49 completed the run-in and were randomized to carvedilol (n=26) or placebo (n=23). Baseline echocardiography demonstrated median (inter-quartile range) GLS of -14.27% (-16.63 to -11.93). NTproBNP and hs-TnT correlated with GLS (Spearman's rho=0.34 [p=0.018] and rho=0.28 [p=0.049], respectively). Median change scores from baseline to 12 months did not differ significantly between participants with complete biomarker data randomized to carvedilol (n=15) or placebo (n=16) for any biomarkers. CONCLUSIONS: NT-proBNP and hs-TnT were associated with GLS. However, changes in levels of the biomarkers from baseline to 12 months were not different between groups randomized to carvedilol and placebo.

Should nephrologists consider vascular calcification screening?

Vascular calcification (VC) has been widely discussed over the last few decades and is associated with significant morbidity and mortality among patients with chronic kidney disease. Importantly, these patients have premature and rapidly progressive calcification when compared with the general population. VC is an active and complex process that is closely regulated by a growing list of inducers and inhibitors. VC can be detected using several non-invasive modalities including plain radiography, echocardiogram and computed tomography scans. However, the usefulness of these imaging measurements to capture treatment effects may be limited. Routine screening and monitoring for progression of VC remains highly debatable.

Association between serum hepcidin-25 and primary resistance to erythropoiesis-stimulating agents in chronic kidney disease: a secondary analysis of the HERO trial.

BACKGROUND: Pentoxifylline has been shown to increase haemoglobin levels in patients with chronic kidney disease (CKD) and erythropoietin-stimulating agent (ESA)-hyporesponsive anaemia in the Handling Erythropoietin Resistance with Oxpentifylline multicentre double-blind, randomized controlled trial. The present sub-study evaluated the effects of pentoxifylline on the iron-regulatory hormone hepcidin in patients with ESA-hyporesponsive CKD. METHODS: This sub-study included 13 patients in the pentoxifylline arm (400 mg daily) and 13 in the matched placebo arm. Hepcidin-25 was measured by ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry following isolation from patient serum. Serum hepcidin-25, serum iron biomarkers, haemoglobin and ESA dosage were compared within and between the two groups. RESULTS: Hepcidin-25 concentration at 4 months adjusted for baseline did not differ significantly in pentoxifylline versus placebo treated patients (adjusted mean difference (MD) -7.9 nmol, P = 0.114), although the difference between the groups mean translated into a >25% reduction of circulating hepcidin-25 due to pentoxifylline compared with the placebo baseline. In paired analysis, serum hepcidin-25 levels were significantly decreased at 4 months compared with baseline in the pentoxifylline group (-5.47 ± 2.27 nmol/l, P < 0.05) but not in the placebo group (2.82 ± 4.29 nmol/l, P = 0.24). Pentoxifylline did not significantly alter serum ferritin (MD 55.4 mcg/l), transferrin saturation (MD 4.04%), the dosage of ESA (MD -9.93 U/kg per week) or haemoglobin concentration (MD 5.75 g/l). CONCLUSION: The reduction of circulating hepcidin-25 due to pentoxifylline did not reach statistical significance; however, the magnitude of the difference suggests that pentoxifylline may be a clinically and biologically meaningful modulator of hepcidin-25 in dialysis of patients with ESA-hyporesponsive anaemia.

Patterns of use and appropriateness of antibiotics prescribed to patients receiving haemodialysis: an observational study.

BACKGROUND: There are limited published data on the types and appropriateness of oral and intravenous (IV) antibiotics prescribed to patients receiving haemodialysis. This information is critical to optimise antibiotic prescribing. Therefore this study aims to describe the patterns of use and the appropriateness of oral and IV antibiotics prescribed to patients receiving haemodialysis. METHODS: This was a prospective, observational study across four community and two hospital inpatient haemodialysis units in Melbourne, Australia. Data were collected from July 2014 to January 2015 from participants. Antibiotic regimens prescribed were compared with nationally available antibiotic guidelines and then classified as being either appropriate, inappropriate or not assessable by an expert multidisciplinary team using the National Antimicrobial Prescribing Survey tool. RESULTS: Overall, 114 participants consented to this study where 55.3% (63/114) received antibiotics and 235 antibiotic regimens were prescribed at a rate of 69.1 antibiotic regimens/100 patient-months. The most common oral antibiotics prescribed were amoxycillin/clavulanic acid and cephalexin. The most common IV antibiotics prescribed were vancomycin, piperacillin/tazobactam, cephazolin and ceftriaxone. The percentage of inappropriate antibiotic regimens prescribed were 34.9% (15/43) in the community setting and 22.1% (40/181) in the hospital setting. Furthermore, 29.4% (30/102) of oral and 20.5% (25/122) of IV antibiotic regimens were inappropriate with incorrect dosing as the primary reason. CONCLUSION: Although this study is limited by the sample size, it describes the high antibiotic exposure that patients receiving haemodialysis experience. Of concern is inappropriate dose and frequency being a major issue. This requires interventions focused on the quality use of medicines and antimicrobial stewardship aspects of prescribing in this population.

A randomized, placebo-controlled trial of pentoxifylline on erythropoiesis-stimulating agent hyporesponsiveness in anemic patients with CKD: the Handling Erythropoietin Resistance With Oxpentifylline (HERO) trial.

BACKGROUND: Erythropoiesis-stimulating agent (ESA)-hyporesponsive anemia is common in chronic kidney disease (CKD). Pentoxifylline shows promise as a treatment for ESA-hyporesponsive anemia, but has not been rigorously evaluated. STUDY DESIGN: Multicenter, double-blind, randomized, controlled trial. SETTING & PARTICIPANTS: 53 adult patients with CKD stage 4 or 5 (including dialysis) and ESA-hyporesponsive anemia (hemoglobin≤120g/L and ESA resistance index [calculated as weight-adjusted weekly ESA dose in IU/kg/wk divided by hemoglobin concentration in g/L]≥1.0IU/kg/wk/g/L for erythropoietin-treated patients and ≥0.005µg/kg/wk/g/L for darbepoetin-treated patients). INTERVENTIONS: Pentoxifylline (400mg/d; n=26) or matching placebo (control; n=27) for 4 months. PRIMARY OUTCOME: ESA resistance index at 4 months; secondary outcomes: hemoglobin concentration, ESA dose, blood transfusion requirement, serum ferritin level and transferrin saturation, C-reactive protein level, adverse events, quality of life, and health economics. RESULTS: There was no statistically significant difference in ESA resistance index between the pentoxifylline and control groups (adjusted mean difference, -0.39 [95%CI, -0.89 to 0.10] IU/kg/wk/g/L; P=0.1). Pentoxifylline significantly increased hemoglobin concentration relative to the control group (adjusted mean difference, 7.6 [95%CI, 1.7-13.5] g/L; P=0.01). There was no difference in ESA dose between groups (-20.8 [95%CI, -67.2 to 25.7] IU/kg/wk; P=0.4). No differences in blood transfusion requirements, adverse events, or quality of life were observed between groups. Pentoxifylline cost A$88.05 (US $82.94) per person over the trial and produced mean savings in ESA cost of A$1,332 (US $1,255). The overall economic impact over the trial period was a saving of A$1,244 (US $1,172) per person for the pentoxifylline group compared with controls. LIMITATIONS: Sample size smaller than planned due to slow recruitment. CONCLUSIONS: Pentoxifylline did not significantly modify ESA hyporesponsiveness, but increased hemoglobin concentration. Further studies are warranted to determine whether pentoxifylline therapy represents a safe strategy for increasing hemoglobin levels in patients with CKD with ESA-hyporesponsive anemia.

Protocol adherence and the progression of cardiovascular calcification in the ADVANCE study.

BACKGROUND: The ADVANCE study assessed the progression of vascular and cardiac valve calcification in 360 hemodialysis patients with secondary hyperparathyroidism (sHPT) assigned randomly to treatment either with cinacalcet plus low-dose vitamin D (≤ 6 µg/week of intravenous paricalcitol equivalent) or with varying doses of vitamin D alone for 52 weeks. The primary efficacy endpoint was progression of coronary artery calcification (CAC). METHODS: In this post-hoc analysis, we compared CAC progression among 70 protocol-adherent subjects given cinacalcet and low doses of vitamin D (CPA) as specified in the study protocol and 120 control subjects given vitamin D sterols. RESULTS: Baseline patient characteristics did not differ between CPA and control subjects. The mean (standard error of the mean, SEM) doses of vitamin D at week 2 were 4.7 (0.3) and 12.8 (1.0) µg/week in CPA and control subjects, respectively, and the corresponding mean cumulative doses of vitamin D over 52 weeks in each group were 225 (22) and 671 (47) µg. The median change in Agatston CAC score after 52 weeks was less in CPA subjects than in controls (17.8% versus 31.3%, P = 0.02). The median increase in calcification scores in the aortic valve also was less in CPA subjects than in controls (6.0% versus 51.5% P = 0.02). Reductions in serum parathyroid hormone, calcium and phosphorus levels were significantly greater in CPA subjects than in controls (P < 0.05). CONCLUSIONS: The progression of cardiovascular calcification was attenuated among cinacalcet-treated subjects with sHPT given low doses of vitamin D per protocol compared with control subjects in whom sHPT was treated with higher doses of vitamin D sterols alone.

Serum fetuin-A concentration and fetuin-A-containing calciprotein particles in patients with chronic inflammatory disease and renal failure.

AIM: Fetuin-A (Fet-A) is an important regulator of extracellular matrix mineralization. Fet-A plays a critical role in the formation and stabilization of high molecular weight colloidal protein-mineral complexes known as calciprotein particles (CPP). The aim of this study was to examine the effects of inflammation, renal function and dialysis modality on serum Fet-A and CPP. METHODS: This is an observational study of patients with chronic kidney disease (CKD) and those with chronic inflammatory disease (CID) but normal renal function. Serum CPP were quantified indirectly by analysing the apparent reduction in serum Fet-A concentration (reduction ratio, RR) after high-speed centrifugation. RESULTS: Serum total Fet-A concentrations are reduced in renal disease and in patients with CID. CPP were not detectable in the serum of normal individuals. CPP represent an increasing percentage of total circulating Fet-A concentrations in patients with CID (RR, 13.3 ± 8.5%), as well as in patients with pre-dialysis CKD (12.4 ± 7.3%) and those undergoing peritoneal dialysis (RR, 22.8 ± 6.0%) or haemodialysis (RR, 38.1 ± 12.8%). The highest Fet-A RR were found in patients with calcific uraemic arteriolopathy (CUA) on haemodialysis (73.9 ± 15.6%). Serum total Fet-A concentrations and Fet-A reduction ratios decreased during a single haemodialysis session, by 24% (P < 0.001) and 34% (P < 0.001), respectively. CONCLUSION: Inflammation appears to be associated with mineral stress even in the absence of renal dysfunction. Patients with CUA on haemodialysis have very high serum Fet-A reduction ratios, suggesting that this measurement may have a prognostic/diagnostic role in this condition.

Differential effects of phosphate binders on pre-dialysis serum bicarbonate in end-stage kidney disease patients on maintenance haemodialysis.

BACKGROUND: Phosphate binders' constituents have alkalotic or acidotic properties and may contribute to acid base balance in haemodialysis patients. This study aimed to investigate the differential effects of phosphate binders on pre-dialysis serum bicarbonate in End Stage Kidney Disease patients on maintenance haemodialysis. METHODS: Stable out-patients having satellite haemodialysis for at least 3 months were retrospectively studied for 18 months, excluding those with other medical causes for metabolic acidosis. Blood results were censored for inpatient episodes, at the time of death, renal transplant or dialysis modality change. Multivariable multilevel mixed-effects linear regression was used and five groups of phosphate binders were compared: Group A(Calcium (Ca) and/or Aluminium (Al) binders); B(Sevelamer hydrochloride (SH) alone); C(lanthanum carbonate (LC) alone); D(SH and Ca/Al), E(LC and Ca/Al). RESULTS: Of 320 patients, 292 were eligible for analysis with a mean follow-up of 15.54 (standard deviation, SD 3.98) months. Similar mean pre-dialysis serum levels of bicarbonate were observed at all 6 month-interval analyses. At 18(th) months, observed mean serum bicarbonate levels in mmol/L were Group B: 21.58 (SD 2.82, P<0.001), C: 23.29 (SD 2.80, P=0.02), D: 21.56 (SD 3.00, P<0.001), and E: 21.29 (SD 3.62, P=0.92) compared with Group A: 22.98 (SD 2.77). Mean serum bicarbonate was related to total SH dose in mmol/L: 22.34 (SD 2.56) for SH <2.5 g/day, 21.61 (SD 2.62) for SH 2.5-4.8 g/day, 21.04 (SD 3.31) for SH >4.8 g/day compared with 22.85 (SD 2.91) for non-users; P-trend<0.001. CONCLUSIONS: Phosphate binders' constituents may contribute to/protect against a predisposition to pre-dialysis metabolic acidosis. This may be dose dependant in patients taking Sevelamer Hydrochloride.

Factors associated with chronic kidney disease progression in Australian nephrology practices.

BACKGROUND/AIMS: Chronic kidney disease (CKD) is a major health issue worldwide. The aim of this study was to explore factors associated with CKD progression in Australian nephrology practices. METHODS: This was a retrospective study utilising an electronic medical record (EMR), Audit4 (Software for Specialists, Australia). The baseline visit was defined as the first entry into the EMR. The primary outcome was the rate of change in estimated glomerular filtration rate (eGFR). RESULTS: 1,328 patients were included with a mean eGFR at baseline of 37.4 ± 0.7 ml/min/1.73 m(2), a mean follow-up of 17.7 months and a mean annual rate of change in eGFR of -0.84 ± 0.26 ml/min/1.73 m(2). Univariate analysis demonstrated that women, smokers, and patients prescribed erythropoiesis-stimulating agents (ESA) had a significantly more rapid decline in eGFR (p = 0.007, 0.033, and 0.003, respectively). On multivariate analysis: gender, age, prescription of ESA and phosphate binders, and baseline eGFR were significantly associated with CKD progression (p = 0.003, 0.004, <0.001, 0.029, and <0.001, respectively). CONCLUSIONS: This study identifies potential factors associated with CKD progression in a population referred to nephrologists, but current data quality may result in bias. Implementation of changes in the format of data collection is required so that busy clinicians record essential information to enable this to become a more accurate and reliable research tool.

Phosphate in early chronic kidney disease: associations with clinical outcomes and a target to reduce cardiovascular risk.

There is an intimate association between mineral and bone disorders in chronic kidney disease (CKD) and the extensive burden of cardiovascular disease (CVD) in this population. High phosphate levels in CKD have been associated with increased all-cause mortality and cardiovascular morbidity and mortality. Observational studies have also shown a consistent relationship between serum phosphate in the normal range and all-cause and cardiovascular mortality, left ventricular hypertrophy (LVH) and decline in renal function. Furthermore, fibroblast growth factor-23 (FGF-23), a phosphaturic hormone, increases very early in the course of CKD and is strongly associated with death and CVD, including LVH and vascular calcification. Few studies have addressed outcomes using interventions to reduce serum phosphate in a randomized controlled fashion; however, strategies to address cardiovascular risk in early CKD are imperative and phosphate is a potential therapeutic target. This review outlines the epidemiological and experimental evidence highlighting the relationship between excess phosphate and adverse outcomes, and discusses clinical studies required to address this problem.

Improving CKD-MBD management in haemodialysis patients: barrier analysis for implementing better practice.

BACKGROUND: Although clinical guidelines exist for optimal levels of serum markers of chronic kidney disease mineral and bone disorder (CKD-MBD), target parameters are not achieved in many haemodialysis (HD) patients. The reason for this evidence-practice gap is unclear and more information from patients and healthcare professionals is required to improve knowledge transfer. We aimed to determine potential barriers by surveying HD patients and staff about awareness and management of CKD-MBD. METHODS: A total of 136 prevalent HD patients, 25 nephrologists and 58 dialysis nurses/technicians were surveyed. Three separate questionnaires included issues of knowledge and awareness of CKD-MBD and factors limiting management (including compliance, medications and general understanding). RESULTS: Of patients surveyed, 84% had heard of phosphate, but 42% were unsure of high phosphate foods and 46% unaware of consequences of elevated phosphate. Twenty-seven percent and thirty-five percent of patients, respectively, had difficulty taking or forgetting to take phosphate binders. Seventy-four percent of patients wanted to know more about CKD-MBD (40% via written material). Of nephrologists surveyed, 76% thought non-compliance with phosphate binders was the main reason for poor control of phosphate (predominantly related to poor patient understanding); 84% thought patients wanted to know more but only 28% provided written material on CKD-MBD. Of dialysis staff surveyed, 63% thought non-compliance with binders explained poor control, the main reason being lack of patient understanding; 88% thought patients wanted to know more but only 17% provided written education. CONCLUSIONS: Implementation of an intensive educational programme, with a multi-faceted approach, for HD patients may promote better control of CKD-MBD and improve achievement of target levels.

Lateral lumbar X-ray assessment of abdominal aortic calcification in Australian haemodialysis patients.

AIM: Vascular calcification is prevalent in patients with chronic kidney disease. Abdominal aortic calcification (AAC) can be detected by X-ray, although AAC is less well documented in anatomical distribution and severity compared with coronary calcification. Using simple radiological imaging we aimed to assess AAC and determine associations in prevalent Australian haemodialysis (HD) patients. METHODS: Lateral lumbar X-ray of the abdominal aorta was used to determine AAC, which is related to the severity of calcific deposits at lumbar vertebral segments L1 to L4. Two radiologists determined AAC scores, by semi-quantitative measurement using a validated 24-point scale, on HD patients from seven satellite dialysis centres. Regression analysis was used to determine associations between AAC and patient characteristics. RESULTS: Lateral lumbar X-ray was obtained in 132 patients. Median age of patients was 69 years (range 29-90), 60% were male, 36% diabetic, median duration of HD 38 months (range 6-230). Calcification (AAC score ≥ 1) was present in 94.4% with mean AAC score 11.0 ± 6.4 (median 12). Independent predictors for the presence and severity of calcification were age (P = 0.03), duration of dialysis (P = 0.04) and a history of cardiovascular disease (P = 0.009). There was no significant association between AAC and the presence of diabetes or time-averaged serum markers of mineral metabolism, lipid status and C-reactive protein. CONCLUSIONS: AAC detected by lateral lumbar X-ray is highly prevalent in our cohort of Australian HD patients and is associated with cardiovascular disease, increasing age and duration of HD. This semi-quantitative method of determining vascular calcification is widely available and inexpensive and may assist cardiovascular risk stratification.

Increased iron requirement in hemodialysis patients on antiplatelet agents or warfarin.

BACKGROUND/AIMS: Many hemodialysis patients receive antiplatelet therapy or warfarin; however, little is known about the effect of this on iron requirements. Given the association of antiplatelet therapy with bleeding we hypothesized that there should be a greater need for iron in such patients, which we tested in this study. METHODS: Retrospective 1-year cohort study of 205 chronic hemodialysis patients. The primary outcome variable was total iron dose, which was analyzed according to antiplatelet/warfarin use. Data were also collected on potential confounders, allowing for both unadjusted and adjusted (multiple regression) analysis. RESULTS: 97/205 patients received antiplatelet/warfarin therapy. This group was older, with a higher incidence of macrovascular disease and diabetes and a higher median C-reactive protein (6.0 vs. 3.75 mg/l). Overall, median iron requirement was 1,300 mg/year. In a multiple regression analysis, antiplatelet/warfarin use was associated with an additional iron requirement of 703 mg (95% confidence interval 188-1,220 mg), with the strongest effect observed in patients with normal inflammatory markers. CONCLUSION: We found a high requirement for iron in patients receiving antiplatelet agents/warfarin. We argue that the most likely mechanism for this association is chronic, low-grade blood loss, although further study is required before causality can be established.

Oxpentifylline versus placebo in the treatment of erythropoietin-resistant anaemia: a randomized controlled trial.

BACKGROUND: The main hypothesis of this study is that Oxpentifylline administration will effectively treat erythropoietin- or darbepoietin-resistant anaemia in chronic kidney disease patients. METHODS/DESIGN: Inclusion criteria are adult patients with stage 4 or 5 chronic kidney disease (including dialysis patients) with significant anaemia (haemoglobin or= 200 IU/kg/week) or darbepoetin (>or= 1 microg/kg/week). Patients will be randomized 1:1 to receive either placebo (1 tablet daily) or oxpentifylline (400 mg daily) per os for a period of 4 months. During this 4 month study period, haemoglobin measurements will be performed monthly. The primary outcome measure will be the difference in haemoglobin level between the 2 groups at the end of the 4 month study period, adjusted for baseline values. Secondary outcome measures will include erythropoiesis stimulating agent dosage, Key's index (erythropoiesis stimulating agent dosage divided by haemoglobin concentration), and blood transfusion requirement. DISCUSSION: This investigator-initiated multicentre study has been designed to provide evidence to help nephrologists and their chronic kidney disease patients determine whether oxpentifylline represents a safe and effective strategy for treating erythropoiesis stimulating agent resistance in chronic kidney disease.

Vancomycin dosing in chronic high-flux haemodialysis: a systematic review.

The aim of this study was to systematically evaluate whether non-weight-based dosing (non-WBD) or weight-based dosing (WBD) of vancomycin leads to a higher proportion of patients achieving the pharmacokinetic/pharmacodynamic target. Studies from January 1985 to February 2017 were identified through Cochrane, MEDLINE and Embase databases. Those conducted in adults with end-stage renal disease receiving high-flux haemodialysis (HD) and intravenous vancomycin were included. The primary outcome was the proportion of patients with a pre-HD vancomycin concentration of 15-20 mg/L and/or an area under the concentration-time curve/minimum inhibitory concentration (AUC/MIC) ratio ≥400. Of the 3948 studies screened, 5 met the inclusion criteria. The proportion of patients with pre-HD concentrations between 15-20 mg/L were 35% (non-WBD) and 13% (WBD) post-loading dose. During maintenance dosing, the proportion of patients with pre-HD concentrations between 15-20 mg/L were 37% (non-WBD) and 50-67% (WBD). The proportion of pre-HD concentrations <15 mg/L was greater in the non-WBD group post-loading dose but was similar between the non-WBD and WBD group during maintenance dosing. One study reported that all patients had an AUC/MIC ≥ 400 for micro-organisms with an MIC ≤ 1 mg/L for weight-based maintenance dosing. The limited data suggest that WBD may be preferential as there was a smaller proportion of pre-HD concentrations falling below 15 mg/L. However, larger well-designed studies of higher quality are required to provide guidance for vancomycin dosing in the high-flux HD setting. Future research should focus on reporting AUC/MIC ratios and exploring clinical outcomes in this patient population.

The effect of pentoxifylline on oxidative stress in chronic kidney disease patients with erythropoiesis-stimulating agent hyporesponsiveness: Sub-study of the HERO trial.

OBJECTIVE: Pentoxifylline has previously been shown to increase haemoglobin levels in patients with chronic kidney disease (CKD) and erythropoietin-stimulating agent (ESA)-hyporesponsive anaemia in the HERO multi-centre double-blind, randomized controlled trial. The present study evaluated the effects of pentoxifylline on oxidative stress in ESA-hyporesponsive CKD patients. METHODS: This sub-study of the HERO trial compared 15 patients in the pentoxifylline arm (400 mg daily) and 17 in the matched placebo arm on oxidative stress markers: plasma total F2-isoprostanes, protein carbonyls, glutathione peroxidase (GPX), and superoxide dismutase (SOD) activities. RESULTS: Pentoxifylline did not significantly alter total F2-isoprostanes (adjusted mean difference (MD) 35.01 pg/ml, P = 0.11), SOD activity (MD 0.82 U/ml, P = 0.07), GPX activity (MD -6.06 U/l, P = 0.09), or protein carbonyls (MD -0.04 nmol/mg, P = 0.52). Replicating results from the main study, pentoxifylline significantly increased haemoglobin concentration compared with controls (MD 7.2 g/l, P = 0.04). CONCLUSIONS: Pentoxifylline did not alter oxidative stress biomarkers, suggesting that alternative mechanisms may be responsible for the agent's ability to augment haemoglobin levels in CKD patients with ESA-hyporesponsive anaemia.