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1.  SYNbiotics Easing Renal failure by improving Gut microbiologY (SYNERGY): a protocol of placebo-controlled randomised cross-over trial 
BMC Nephrology  2014;15:106.
Background
Emerging evidence suggests modulating the microbiota in the large bowel of patients with chronic kidney disease (CKD) through pre- and/probiotic supplementation may inhibit the development of key nephrovascular toxins. To date, quality intervention trials investigating this novel treatment in CKD are lacking. The aim of SYNERGY is to assess the effectiveness of synbiotics (co-administration of pre- and probiotics) as a potential treatment targeting the synthesis of uremic toxins, specifically, indoxyl sulphate (IS) and p-cresyl sulphate (PCS).
Methods/design
Thirty-seven patients with moderate to severe CKD (Stage IV and V, pre-dialysis) will be recruited to a double-blind, placebo-controlled, randomised cross-over trial. Patients will be provided with synbiotic therapy or placebo for 6 weeks, with a 4 week washout before cross-over. The primary outcome is serum IS, total and free (unbound) concentrations, measured using ultra-performance liquid chromatography. Secondary outcomes include serum PCS, total and free (unbound) concentrations; cardiovascular risk, measured by serum lipopolysaccharides, serum trimethylamine-N-oxide (TMAO) and inflammation and oxidative stress markers; kidney damage, measured by 24 hour proteinuria and albuminuria, estimated glomerular filtration rate and renal tubule damage (urinary kidney injury molecule-1); patients’ self assessed quality of life; and gastrointestinal symptoms. In addition, the effects on the community structure of the stool microbiota will be explored in a subset of patients to validate the mechanistic rationale underpinning the synbiotic therapy.
Discussion
IS and PCS are two novel uremic toxins implicated in both cardiovascular disease (CVD) and progression of CKD. Preliminary studies indicate that synbiotic therapy maybe a promising strategy when considering a targeted, tolerable and cost-efficient therapy for lowering serum IS and PCS concentrations. This trial will provide high quality ‘proof-of-concept’ data to elucidate both the efficacy of synbiotic therapy for lowering the toxins and whether reductions in serum IS and PCS translate into clinical benefits. Considering the potential of pre- and probiotics to not only shift toxin levels, but to also impede CVD and CKD progression, SYNERGY will provide vital insight into the effectiveness of this innocuous nutritional therapy.
Trial Registration
Universal Trial Number: U1111-1142-4363. Australian New Zealand Clinical Trials Registry Number: ACTRN12613000493741, date registered: 2nd May 2013.
doi:10.1186/1471-2369-15-106
PMCID: PMC4094543  PMID: 24996842
Prebiotics; Probiotics; Synbiotics; Chronic kidney disease; Gut microbiota; Indoxyl sulphate; P-cresyl sulphate; Endotoxins
2.  A randomized trial of sodium-restriction on kidney function, fluid volume and adipokines in CKD patients 
BMC Nephrology  2014;15:57.
Background
Dietary sodium restriction is a key management strategy in chronic kidney disease (CKD). Recent evidence has demonstrated short-term reduction in blood pressure (BP) and proteinuria with sodium restriction, however the effect on other cardiovascular-related risk factors requires investigation in CKD.
Methods
The LowSALT CKD study involved 20 hypertensive Stage III-IV CKD patients counselled by a dietitian to consume a low-sodium diet (<100 mmol/day). The study was a randomised crossover trial comparing 2 weeks of high-sodium (additional 120 mmol sodium tablets) and low-sodium intake (placebo). Measurements were taken after each crossover arm including BP (peripheral and central), adipokines (inflammation markers and adiponectin), volume markers (extracellular-to-intracellular [E/I] fluid ratio; N-terminal pro-brain natriuretic peptide [NT-proBNP]), kidney function (estimated Glomerular Filtration Rate [eGFR]) and proteinuria (urine protein-creatinine ratio [PCR] and albumin-creatinine ratio [ACR]). Outcomes were compared using paired t-test for each cross-over arm.
Results
BP-lowering benefits of a low-sodium intake (peripheral BP (mean ± SD) 148/82 ± 21/12 mmHg) from high-sodium (159/87 ± 15/10 mmHg) intake were reflected in central BP and a reduction in eGFR, PCR, ACR, NTproBNP and E/I ratio. There was no change in inflammatory markers, total or high molecular weight adiponectin.
Conclusions
Short-term benefits of sodium restriction on BP were reflected in significant change in kidney function and fluid volume parameters. Larger, long-term adequately powered trials in CKD are necessary to confirm these results.
Trial registration
Universal Trial Number U1111-1125-2149 registered on 13/10/2011; Australian New Zealand Clinical Trials Registry Number ACTRN12611001097932 registered on 21/10/2011.
doi:10.1186/1471-2369-15-57
PMCID: PMC3994521  PMID: 24708818
Dietary sodium; Nutrition; Chronic kidney disease; Cardiovascular disease; Blood pressure; Kidney function; Inflammation
3.  Dialysate interleukin-6 predicts increasing peritoneal solute transport rate in incident peritoneal dialysis patients 
BMC Nephrology  2014;15:8.
Background
Repeated exposure to peritoneal dialysis (PD) solutions contributes to cumulative intraperitoneal inflammation and peritoneal injury. The present study aimed to explore the capacity of dialysate interleukin-6(IL-6) to a) predict peritoneal membrane function and peritonitis in incident PD patients, and b) to evaluate the influence of neutral pH, low glucose degradation product (GDP) PD solution on dialysate IL-6 levels.
Methods
The study included 88 incident participants from the balANZ trial who had completed 24-months of follow-up. Change in peritoneal solute transport rate (PSTR) and peritonitis were primary outcome measures, and the utility of IL-6 and IL-6 appearance rate (IL-6 AR) in predicting these outcomes was analyzed using multilevel linear regression and Cox proportional hazards models, respectively. Sensitivity analyses were performed by analyzing outcomes in a peritonitis-free cohort (n = 56).
Results
Dialysate IL-6 concentration significantly increased from baseline to 24 months (mean difference 19.07 pg/mL; P < 0.001) but was not affected by the type of PD solution received (P = 0.68). An increase in PSTR from baseline was associated with higher levels of IL-6 (P = 0.004), the use of standard solutions (P = 0.005) and longer PD duration (P < 0.001). Baseline IL-6 level was not associated with a shorter time to first peritonitis (adjusted hazard ratio 1.00, 95% CI 0.99-1.00, P = 0.74). Analysis of IL-6 AR as well as sensitivity analyses in a peritonitis-free cohort yielded comparable results.
Conclusion
Dialysate IL-6 concentration increased with longer PD duration and was a significant, independent predictor of PSTR. The use of biocompatible PD solutions exerted no significant effect on dialysate IL-6 levels but did abrogate the increase in PSTR associated with standard PD solutions. This is the first study to examine the impact of biocompatible solutions on the utility of IL-6 in predicting PSTR and peritonitis.
doi:10.1186/1471-2369-15-8
PMCID: PMC3893539  PMID: 24410736
Biocompatible; Glucose degradation products; Interleukin-6; Peritoneal dialysis; Peritoneal solute transport rate; Peritonitis
4.  Oral disease in adults treated with hemodialysis: prevalence, predictors, and association with mortality and adverse cardiovascular events: the rationale and design of the ORAL Diseases in hemodialysis (ORAL-D) study, a prospective, multinational, longitudinal, observational, cohort study 
BMC Nephrology  2013;14:90.
Background
People with end-stage kidney disease treated with dialysis experience high rates of premature death that are at least 30-fold that of the general population, and have markedly impaired quality of life. Despite this, interventions that lower risk factors for mortality (including antiplatelet agents, epoetins, lipid lowering, vitamin D compounds, or dialysis dose) have not been shown to improve clinical outcomes for this population. Although mortality outcomes may be improving overall, additional modifiable determinants of health in people treated with dialysis need to be identified and evaluated.
Oral disease is highly prevalent in the general population and represents a potential and preventable cause of poor health in dialysis patients. Oral disease may be increased in patients treated with dialysis due to their lower uptake of public dental services, as well as increased malnutrition and inflammation, although available exploratory data are limited by small sample sizes and few studies evaluating links between oral health and clinical outcomes for this group, including mortality and cardiovascular disease. Recent data suggest periodontitis may be associated with mortality in dialysis patients and well-designed, larger studies are now required.
Methods/design
The ORAL Diseases in hemodialysis (ORAL-D) study is a multinational, prospective (minimum follow-up 12 months) study. Participants comprise consecutive adults treated with long-term in-center hemodialysis. Between July 2010 and February 2012, we recruited 4500 dialysis patients from randomly selected outpatient dialysis clinics in Europe within a collaborative network of dialysis clinics administered by a dialysis provider, Diaverum, in Europe (France, Hungary, Italy, Poland, Portugal, and Spain) and South America (Argentina). At baseline, dental surgeons with training in periodontology systematically assessed the prevalence and characteristics of oral disease (dental, periodontal, mucosal, and salivary) in all participants. Oral hygiene habits and thirst were evaluated using self-administered questionnaires. Data for hospitalizations and mortality (total and cause-specific) according to baseline oral health status will be collected once a year until 2022.
Discussion
This large study will estimate the prevalence, characteristics and correlations of oral disease and clinical outcomes (mortality and hospitalization) in adults treated with dialysis. We will further evaluate any association between periodontitis and risk of premature death in dialysis patients that has been suggested by existing research. The results from this study should provide powerful new data to guide strategies for future interventional studies for preventative and curative oral disease strategies in adults who have end-stage kidney disease.
doi:10.1186/1471-2369-14-90
PMCID: PMC3685555  PMID: 23597063
Chronic kidney disease; Oral disease; Periodontitis; Mortality; Prevalence
5.  End-stage kidney disease due to haemolytic uraemic syndrome – outcomes in 241 consecutive ANZDATA registry cases 
BMC Nephrology  2012;13:164.
Background
The aim of this study was to investigate the characteristics and outcomes of patients receiving renal replacement therapy for end-stage kidney disease (ESKD) secondary to haemolytic uraemic syndrome (HUS).
Methods
The study included all patients with ESKD who commenced renal replacement therapy in Australia and New Zealand between 15/5/1963 and 31/12/2010, using data from the ANZDATA Registry. HUS ESKD patients were compared with matched controls with an alternative primary renal disease using propensity scores based on age, gender and treatment era.
Results
Of the 58422 patients included in the study, 241 (0.4%) had ESKD secondary to HUS. HUS ESKD was independently associated with younger age, female gender and European race. Compared with matched controls, HUS ESKD was not associated with mortality on renal replacement therapy (adjusted hazard ratio [HR] 1.14, 95% CI 0.87-1.50, p = 0.34) or dialysis (HR 1.34, 95% CI 0.93-1.93, p = 0.12), but did independently predict recovery of renal function (HR 54.01, 95% CI 1.45-11.1, p = 0.008). 130 (54%) HUS patients received 166 renal allografts. Overall renal allograft survival rates were significantly lower for patients with HUS ESKD at 1 year (73% vs 91%), 5 years (62% vs 85%) and 10 years (49% vs 73%). HUS ESKD was an independent predictor of renal allograft failure (HR 2.59, 95% CI 1.70-3.95, p < 0.001). Sixteen (12%) HUS patients experienced failure of 22 renal allografts due to recurrent HUS. HUS ESKD was not independently associated with the risk of death following renal transplantation (HR 0.92, 95% CI 0.35-2.44, p = 0.87).
Conclusions
HUS is an uncommon cause of ESKD, which is associated with comparable patient survival on dialysis, an increased probability of renal function recovery, comparable patient survival post-renal transplant and a heightened risk of renal transplant graft failure compared with matched ESKD controls.
doi:10.1186/1471-2369-13-164
PMCID: PMC3544575  PMID: 23206870
Haemolytic uraemic syndrome; Kidney Failure; Chronic; Outcomes; Renal function recovery; Renal transplantation; Thrombotic microangiopathy
6.  A randomised controlled trial of Heparin versus EthAnol Lock THerapY for the prevention of Catheter Associated infecTion in Haemodialysis patients – the HEALTHY-CATH trial 
BMC Nephrology  2012;13:146.
Background
Tunnelled central venous dialysis catheter use is significantly limited by the occurrence of catheter-related infections. This randomised controlled trial assessed the efficacy of a 48 hour 70% ethanol lock vs heparin locks in prolonging the time to the first episode of catheter related blood stream infection (CRBSI).
Methods
Patients undergoing haemodialysis (HD) via a tunnelled catheter were randomised 1:1 to once per week ethanol locks (with two heparin locks between other dialysis sessions) vs thrice per week heparin locks.
Results
Observed catheter days in the heparin (n=24) and ethanol (n=25) groups were 1814 and 3614 respectively. CRBSI occurred at a rate of 0.85 vs. 0.28 per 1000 catheter days in the heparin vs ethanol group by intention to treat analysis (incident rate ratio (IRR) for ethanol vs. heparin 0.17; 95%CI 0.02-1.63; p=0.12). Flow issues requiring catheter removal occurred at a rate of 1.6 vs 1.4 per 1000 catheter days in the heparin and ethanol groups respectively (IRR 0.85; 95% CI 0.20-3.5 p =0.82 (for ethanol vs heparin).
Conclusions
Catheter survival and catheter-related blood stream infection were not significantly different but there was a trend towards a reduced rate of infection in the ethanol group. This study establishes proof of concept and will inform an adequately powered multicentre trial to definitively examine the efficacy and safety of ethanol locks as an alternative to current therapies used in the prevention of catheter-associated blood stream infections in patients dialysing with tunnelled catheters.
Trial Registration
Australian New Zealand Clinical Trials Registry ACTRN12609000493246
doi:10.1186/1471-2369-13-146
PMCID: PMC3531247  PMID: 23121768
Catheter related blood stream infection (CRBSI); Central venous catheter; Ethanol; Lock therapy; Haemodialysis (HD); Prophylaxis
7.  The effect of lowering salt intake on ambulatory blood pressure to reduce cardiovascular risk in chronic kidney disease (LowSALT CKD study): protocol of a randomized trial 
BMC Nephrology  2012;13:137.
Background
Despite evidence implicating dietary sodium in the pathogenesis of cardiovascular disease (CVD) in chronic kidney disease (CKD), quality intervention trials in CKD patients are lacking. This study aims to investigate the effect of reducing sodium intake on blood pressure, risk factors for progression of CKD and other cardiovascular risk factors in CKD.
Methods/design
The LowSALT CKD study is a six week randomized-crossover trial assessing the effect of a moderate (180 mmol/day) compared with a low (60 mmol/day) sodium intake on cardiovascular risk factors and risk factors for kidney function decline in mild-moderate CKD (stage III-IV). The primary outcome of interest is 24-hour ambulatory blood pressure, with secondary outcomes including arterial stiffness (pulse wave velocity), proteinuria and fluid status. The randomized crossover trial (Phase 1) is supported by an ancillary trial (Phase 2) of longitudinal-observational design to assess the longer term effectiveness of sodium restriction. Phase 2 will continue measurement of outcomes as per Phase 1, with the addition of patient-centered outcomes, such as dietary adherence to sodium restriction (degree of adherence and barriers/enablers), quality of life and taste assessment.
Discussion
The LowSALT CKD study is an investigator-initiated study specifically designed to assess the proof-of-concept and efficacy of sodium restriction in patients with established CKD. Phase 2 will assess the longer term effectiveness of sodium restriction in the same participants, enhancing the translation of Phase 1 results into practice. This trial will provide much-needed insight into sodium restriction as a treatment option to reduce risk of CVD and CKD progression in CKD patients.
Trial registration
Universal Trial Number: U1111-1125-2149. Australian New Zealand Clinical Trials Registry Number: ACTRN12611001097932
doi:10.1186/1471-2369-13-137
PMCID: PMC3524774  PMID: 23082956
Dietary sodium; Chronic kidney disease; Blood pressure; Cardiovascular disease; Arterial stiffness; Clinical trial; Patient compliance; Taste disturbance
8.  Association of pre-transplant statin use with delayed graft function in kidney transplant recipients 
BMC Nephrology  2012;13:111.
Background
Administration of HMG-CoA reductase inhibitors (statins), prior to ischemia or prior to reperfusion has been shown to decrease ischemia-reperfusion renal injury in animal studies. It is unknown whether this protective effect is applicable to renal transplantation in humans. The aim of this study was to determine the relationship between prior statin use in renal transplant recipients and the subsequent risk of delayed graft function.
Methods
All patients who underwent deceased or living donor renal transplantation at the Princess Alexandra Hospital between 1 July 2008 and 1 August 2010 were included in this retrospective, observational cohort study. Graft function was classified as immediate graft function (IGF), dialysis-requiring (D-DGF) and non-dialysis-requiring (ND-DGF) delayed graft function. The independent predictors of graft function were evaluated by multivariable logistic regression, adjusting for donor characteristics, recipient characteristics, HLA mismatch and ischaemic times.
Results
Overall, of the 266 renal transplant recipients, 21% exhibited D-DGF, 39% had ND-DGF and 40% had IGF. Statin use prior to renal transplantation was not significantly associated with the risk of D-DGF (adjusted odds ratio [OR] 1.05, 95% CI 0.96 – 1.15, P = 0.28). This finding was not altered when D-DGF and ND-DGF were pooled together (OR 0.98; 95% CI 0.89-1.06, p = 0.56).
Conclusions
The present study did not show a significant, independent association between prior statin use in kidney transplant recipients and the occurrence of delayed graft function.
doi:10.1186/1471-2369-13-111
PMCID: PMC3507677  PMID: 22985048
9.  The effects of living distantly from peritoneal dialysis units on peritonitis risk, microbiology, treatment and outcomes: a multi-centre registry study 
BMC Nephrology  2012;13:41.
Background
The aim of the study was to determine whether distance between residence and peritoneal dialysis (PD) unit influenced peritonitis occurrence, microbiology, treatment and outcomes.
Methods
The study included all patients receiving PD between 1/10/2003 and 31/12/2008, using ANZDATA Registry data.
Results
365 (6%) patients lived ≥100 km from their nearest PD unit (distant group), while 6183 (94%) lived <100 km (local group). Median time to first peritonitis in distant patients (1.34 years, 95% CI 1.07-1.61) was significantly shorter than in local patients (1.68 years, 95% CI 1.59-1.77, p = 0.001), whilst overall peritonitis rates were higher in distant patients (incidence rate ratio 1.32, 95% CI 1.20-1.46). Living ≥100 km away from a PD unit was independently associated with a higher risk of S. aureus peritonitis (adjusted odds ratio [OR] 1.64, 95% CI 1.09-2.47). Distant patients with first peritonitis episodes were less likely to be hospitalised (64% vs 73%, p = 0.008) and receive antifungal prophylaxis (4% vs 10%, p = 0.01), but more likely to receive vancomycin-based antibiotic regimens (52% vs 42%, p < 0.001). Using multivariable logistic regression analysis of peritonitis outcomes, distant patients were more likely to be cured with antibiotics alone (OR 1.55, 95% CI 1.03-2.24). All other outcomes were comparable between the two groups.
Conclusions
Living ≥100 km away from a PD unit was associated with increased risk of S. aureus peritonitis, modified approaches to peritonitis treatment and peritonitis outcomes that were comparable to, or better than patients living closer to a PD unit. Staphylococcal decolonisation should receive particular consideration in remote living patients.
doi:10.1186/1471-2369-13-41
PMCID: PMC3444345  PMID: 22702659
Antibiotics; Bacteria; Fungus; Microbiology; Peritoneal Dialysis; Peritonitis; Outcomes; Relapse; Remoteness
10.  Cardiac and vascular structure and function parameters do not improve with alternate nightly home hemodialysis: An interventional cohort study 
BMC Nephrology  2011;12:51.
Background
Nightly extended hours hemodialysis may improve left ventricular hypertrophy and function and endothelial function but presents problems of sustainability and increased cost. The effect of alternate nightly home hemodialysis (NHD) on cardiovascular structure and function is not known.
Methods
Sixty-three patients on standard hemodialysis (SHD: 3.5-6 hours/session, 3-5 sessions weekly) converted to NHD (6-10 hours/session overnight for 3-5 sessions weekly). 2Dimensional transthoracic echocardiography and ultrasound measures of brachial artery reactivity (BAR), carotid intima-media thickness (CIMT), total arterial compliance (TAC) and augmentation index (AIX) were performed post dialysis at baseline and 18-24 months following conversion to NHD. In 37 patients, indices of oxidative stress: plasma malonyldialdehyde (MDA) and anti-oxidant enzymes: catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase (SOD) activity and total antioxidant status (TAS) were measured at baseline, 3 and 6 months.
Results
Left ventricular mass index (LVMI) remained stable. Despite significant derangement at baseline, there were no changes in diastolic function measures, CIMT, BAR and TAC. AIX increased. Conversion to NHD improved bone mineral metabolism parameters and blood pressure control. Interdialytic weight gains increased. No definite improvements in measures of oxidative stress were demonstrated.
Conclusions
Despite improvement in uremic toxin levels and some cardiovascular risk factors, conversion to an alternate nightly NHD regimen did not improve cardiovascular structure and function. Continuing suboptimal control of uremic toxins and interdialytic weight gains may be a possible explanation. This study adds to the increasing uncertainty about the nature of improvement in cardiovascular parameters with conversion to intensive hemodialysis regimens. Future randomized controlled trials will be important to determine whether increases in dialysis session duration, frequency or both are most beneficial for improving cardiovascular disease whilst minimizing costs and the impact of dialysis on quality of life.
doi:10.1186/1471-2369-12-51
PMCID: PMC3202231  PMID: 21962236
Diastolic Function; Ejection Fraction; Left Ventricular Mass Index; Left Ventricular Hypertrophy; Nocturnal Hemodialysis; Carotid Intima-Media Thickness; Oxidative Stress; Arterial Compliance
11.  Do aluminium-based phosphate binders continue to have a role in contemporary nephrology practice? 
BMC Nephrology  2011;12:20.
Background
Aluminium-containing phosphate binders have long been used for treatment of hyperphosphatemia in dialysis patients. Their safety became controversial in the early 1980's after reports of aluminium related neurological and bone disease began to appear. Available historical evidence however, suggests that neurological toxicity may have primarily been caused by excessive exposure to aluminium in dialysis fluid, rather than aluminium-containing oral phosphate binders. Limited evidence suggests that aluminium bone disease may also be on the decline in the era of aluminium removal from dialysis fluid, even with continued use of aluminium binders.
Discussion
The K/DOQI and KDIGO guidelines both suggest avoiding aluminium-containing binders. These guidelines will tend to promote the use of the newer, more expensive binders (lanthanum, sevelamer), which have limited evidence for benefit and, like aluminium, limited long-term safety data. Treating hyperphosphatemia in dialysis patients continues to represent a major challenge, and there is a large body of evidence linking serum phosphate concentrations with mortality. Most nephrologists agree that phosphate binders have the potential to meaningfully reduce mortality in dialysis patients. Aluminium is one of the cheapest, most effective and well tolerated of the class, however there are no prospective or randomised trials examining the efficacy and safety of aluminium as a binder. Aluminium continues to be used as a binder in Australia as well as some other countries, despite concern about the potential for toxicity. There are some data from selected case series that aluminium bone disease may be declining in the era of reduced aluminium content in dialysis fluid, due to rigorous water testing.
Summary
This paper seeks to revisit the contemporary evidence for the safety record of aluminium-containing binders in dialysis patients. It puts their use into the context of the newer, more expensive binders and increasing concerns about the risks of calcium binders, which continue to be widely used. The paper seeks to answer whether the continued use of aluminium is justifiable in the absence of prospective data establishing its safety, and we call for prospective trials to be conducted comparing the available binders both in terms of efficacy and safety.
doi:10.1186/1471-2369-12-20
PMCID: PMC3107169  PMID: 21569446
12.  Rationale and design of the balANZ trial: A randomised controlled trial of low GDP, neutral pH versus standard peritoneal dialysis solution for the preservation of residual renal function 
BMC Nephrology  2010;11:25.
Background
The main hypothesis of this study is that neutral pH, low glucose degradation product (GDP) peritoneal dialysis (PD) fluid better preserves residual renal function in PD patients over time compared with conventional dialysate.
Methods/Design
Inclusion criteria are adult PD patients (CAPD or APD) aged 18-81 years whose first dialysis was within 90 days prior to or following enrolment and who have a residual GFR ≥ 5 ml/min/1.73 m2, a urine output ≥ 400 ml/day and an ability to understand the nature and requirements of this trial. Pregnant or lactating patients or individuals with an active infection at the time of enrolment, a contra-indication to PD or participation in any other clinical trial where an intervention is designed to moderate rate of change of residual renal function are excluded. Patients will be randomized 1:1 to receive either neutral pH, low GDP dialysis solution (Balance®) or conventional dialysis solution (Stay.safe®) for a period of 2 years. During this 2 year study period, urinary urea and clearance measurements will be performed at 0, 3, 6, 9, 12, 18 and 24 months. The primary outcome measure will be the slope of residual renal function decline, adjusted for centre and presence of diabetic nephropathy. Secondary outcome measures will include time from initiation of peritoneal dialysis to anuria, peritoneal small solute clearance, peritoneal transport status, peritoneal ultrafiltration, technique survival, patient survival, peritonitis rates and adverse events. A total of 185 patients has been recruited into the trial.
Discussion
This investigator-initiated study has been designed to provide evidence to help nephrologists determine the optimal dialysis solution for preserving residual renal function in PD patients.
Trial Registration
Australian New Zealand Clinical Trials Registry Number: ACTRN12606000044527
doi:10.1186/1471-2369-11-25
PMCID: PMC2954914  PMID: 20843375
13.  The role of 25-hydroxyvitamin D deficiency in promoting insulin resistance and inflammation in patients with Chronic Kidney Disease: a randomised controlled trial 
BMC Nephrology  2009;10:41.
Background
Approximately 50% of patients with stage 3 Chronic Kidney Disease are 25-hydroxyvitamin D insufficient, and this prevalence increases with falling glomerular filtration rate. Vitamin D is now recognised as having pleiotropic roles beyond bone and mineral homeostasis, with the vitamin D receptor and metabolising machinery identified in multiple tissues. Worryingly, recent observational data has highlighted an association between hypovitaminosis D and increased cardiovascular mortality, possibly mediated via vitamin D effects on insulin resistance and inflammation. The main hypothesis of this study is that oral Vitamin D supplementation will ameliorate insulin resistance in patients with Chronic Kidney Disease stage 3 when compared to placebo. Secondary hypotheses will test whether this is associated with decreased inflammation and bone/adipocyte-endocrine dysregulation.
Methods/Design
This study is a single-centre, double-blinded, randomised, placebo-controlled trial. Inclusion criteria include; estimated glomerular filtration rate 30-59 ml/min/1.73 m2; aged ≥18 on entry to study; and serum 25-hydroxyvitamin D levels <75 nmol/L. Patients will be randomised 1:1 to receive either oral cholecalciferol 2000IU/day or placebo for 6 months. The primary outcome will be an improvement in insulin sensitivity, measured by hyperinsulinaemic euglycaemic clamp. Secondary outcome measures will include serum parathyroid hormone, cytokines (Interleukin-1β, Interleukin-6, Tumour Necrosis Factor alpha), adiponectin (total and High Molecular Weight), osteocalcin (carboxylated and under-carboxylated), peripheral blood mononuclear cell Nuclear Factor Kappa-B p65 binding activity, brachial artery reactivity, aortic pulse wave velocity and waveform analysis, and indirect calorimetry. All outcome measures will be performed at baseline and end of study.
Discussion
To date, no randomised controlled trial has been performed in pre-dialysis CKD patients to study the correlation between vitamin D status with supplementation, insulin resistance and markers of adverse cardiovascular risk. We remain hopeful that cholecalciferol may be a safe intervention, with health benefits beyond those related to bone-mineral homeostasis.
Trial registration
Australian and New Zealand Clinical Trials Registry ACTRN12609000246280.
doi:10.1186/1471-2369-10-41
PMCID: PMC2804665  PMID: 20003316
14.  Adiponectin is associated with cardiovascular disease in male renal transplant recipients: baseline results from the LANDMARK 2 study 
BMC Nephrology  2009;10:29.
Background
Adiponectin is a major adipocyte-derived protein with insulin-sensitizing, anti-inflammatory and anti-atherogenic properties. Adiponectin levels correlate inversely with renal function and higher levels are predictive of lower cardiovascular disease (CVD) in patients with normal renal function and chronic kidney disease. No data exists on the association between adiponectin and CVD in renal transplant recipients (RTR).
Methods
Standard biochemistry, clinical data and adiponectin were collected from 137 RTR recruited to the LANDMARK 2 study at baseline. The LANDMARK 2 study is an ongoing randomized controlled study that compares the outcome of aggressive risk factor modification for cardiovascular disease versus standard post-transplant care in renal transplant recipients with impaired glucose tolerance or diabetes mellitus.
Results
Mean patient age was 53.4 ± 12 years and the median post-transplantation period was 5 (0.5-31.9) years. Mean serum adiponectin level was 12.3 ± 7.1 μg/mL. On univariate analysis, adiponectin was positively associated with female gender (P = 0.01) and serum high-density lipoprotein (HDL) concentration (P < 0.001), and inversely with body mass index (P = 0.009), metabolic syndrome (P = 0.047), abnormal glucose tolerance (P = 0.01), C-reactive protein (P = 0.001) and serum triglyceride (P < 0.001). On stepwise multivariate analysis, adiponectin in males was negatively correlated with combined baseline CVD (P = 0.03), waist-hip ratio (P = 0.003) and glomerular filtration rate (P = 0.046), and positively with HDL (P < 0.001). In contrast, in females adiponectin was inversely associated with C-reactive protein (P = 0.001) and serum triglyceride.
Conclusion
In conclusion, adiponectin is positively correlated with inflammation, dyslipidemia and abnormal glucose tolerance in RTR. Furthermore, hypoadiponectinemia correlated with increased baseline CVD in male RTR.
doi:10.1186/1471-2369-10-29
PMCID: PMC2766377  PMID: 19821969
15.  Rationale and design of the HEALTHY-CATH trial: A randomised controlled trial of Heparin versus EthAnol Lock THerapY for the prevention of Catheter Associated infecTion in Haemodialysis patients 
BMC Nephrology  2009;10:23.
Background
Catheter-related bacteraemias (CRBs) contribute significantly to morbidity, mortality and health care costs in dialysis populations. Despite international guidelines recommending avoidance of catheters for haemodialysis access, hospital admissions for CRBs have doubled in the last decade. The primary aim of the study is to determine whether weekly instillation of 70% ethanol prevents CRBs compared with standard heparin saline.
Methods/design
The study will follow a prospective, open-label, randomized controlled design. Inclusion criteria are adult patients with incident or prevalent tunneled intravenous dialysis catheters on three times weekly haemodialysis, with no current evidence of catheter infection and no personal, cultural or religious objection to ethanol use, who are on adequate contraception and are able to give informed consent. Patients will be randomized 1:1 to receive 3 mL of intravenous-grade 70% ethanol into each lumen of the catheter once a week and standard heparin locks for other dialysis days, or to receive heparin locks only. The primary outcome measure will be time to the first episode of CRB, which will be defined using standard objective criteria. Secondary outcomes will include adverse reactions, incidence of CRB caused by different pathogens, time to infection-related catheter removal, time to exit site infections and costs. Prospective power calculations indicate that the study will have 80% statistical power to detect a clinically significant increase in median infection-free survival from 200 days to 400 days if 56 patients are recruited into each arm.
Discussion
This investigator-initiated study has been designed to provide evidence to help nephrologists reduce the incidence of CRBs in haemodialysis patients with tunnelled intravenous catheters.
Trial Registration
Australian New Zealand Clinical Trials Registry Number: ACTRN12609000493246
doi:10.1186/1471-2369-10-23
PMCID: PMC2738669  PMID: 19691852
16.  Rationale and design of the oral HEMe iron polypeptide Against Treatment with Oral Controlled Release Iron Tablets trial for the correction of anaemia in peritoneal dialysis patients (HEMATOCRIT trial) 
BMC Nephrology  2009;10:20.
Background
The main hypothesis of this study is that oral heme iron polypeptide (HIP; Proferrin® ES) administration will more effectively augment iron stores in erythropoietic stimulatory agent (ESA)-treated peritoneal dialysis (PD) patients than conventional oral iron supplementation (Ferrogradumet®).
Methods
Inclusion criteria are peritoneal dialysis patients treated with darbepoietin alpha (DPO; Aranesp®, Amgen) for ≥ 1 month. Patients will be randomized 1:1 to receive either slow-release ferrous sulphate (1 tablet twice daily; control) or HIP (1 tablet twice daily) for a period of 6 months. The study will follow an open-label design but outcome assessors will be blinded to study treatment. During the 6-month study period, haemoglobin levels will be measured monthly and iron studies (including transferring saturation [TSAT] measurements) will be performed bi-monthly. The primary outcome measure will be the difference in TSAT levels between the 2 groups at the end of the 6 month study period, adjusted for baseline values using analysis of covariance (ANCOVA). Secondary outcome measures will include serum ferritin concentration, haemoglobin level, DPO dosage, Key's index (DPO dosage divided by haemoglobin concentration), and occurrence of adverse events (especially gastrointestinal adverse events).
Discussion
This investigator-initiated multicentre study has been designed to provide evidence to help nephrologists and their peritoneal dialysis patients determine whether HIP administration more effectively augments iron stores in ESP-treated PD patients than conventional oral iron supplementation.
Trial Registration
Australia New Zealand Clinical Trials Registry number ACTRN12609000432213.
doi:10.1186/1471-2369-10-20
PMCID: PMC2723098  PMID: 19635169
17.  Streptococcal peritonitis in Australian peritoneal dialysis patients: predictors, treatment and outcomes in 287 cases 
BMC Nephrology  2009;10:19.
Background
There has not been a comprehensive, multi-centre study of streptococcal peritonitis in patients on peritoneal dialysis (PD) to date.
Methods
The predictors, treatment and clinical outcomes of streptococcal peritonitis were examined by binary logistic regression and multilevel, multivariate poisson regression in all Australian PD patients involving 66 centres between 2003 and 2006.
Results
Two hundred and eighty-seven episodes of streptococcal peritonitis (4.6% of all peritonitis episodes) occurred in 256 individuals. Its occurrence was independently predicted by Aboriginal or Torres Strait Islander racial origin. Compared with other organisms, streptococcal peritonitis was associated with significantly lower risks of relapse (3% vs 15%), catheter removal (10% vs 23%) and permanent haemodialysis transfer (9% vs 18%), as well as a shorter duration of hospitalisation (5 vs 6 days). Overall, 249 (87%) patients were successfully treated with antibiotics without experiencing relapse, catheter removal or death. The majority of streptococcal peritonitis episodes were treated with either intraperitoneal vancomycin (most common) or first-generation cephalosporins for a median period of 13 days (interquartile range 8–18 days). Initial empiric antibiotic choice did not influence outcomes.
Conclusion
Streptococcal peritonitis is a not infrequent complication of PD, which is more common in indigenous patients. When treated with either first-generation cephalosporins or vancomycin for a period of 2 weeks, streptococcal peritonitis is associated with lower risks of relapse, catheter removal and permanent haemodialysis transfer than other forms of PD-associated peritonitis.
doi:10.1186/1471-2369-10-19
PMCID: PMC2721833  PMID: 19631002
18.  Intravenous versus oral iron supplementation for correction of post-transplant anaemia in renal transplant patients 
BMC Nephrology  2009;10:14.
Background
Post-transplant anaemia remains a common problem after kidney transplantation, with an incidence ranging from nearly 80% at day 0 to about 25% at 1 year. It has been associated with poor graft outcome, and recently has also been shown to be associated with increased mortality.
Our transplant unit routinely administers oral iron supplements to renal transplant recipients but this is frequently accompanied by side effects, mainly gastrointestinal intolerance. Intravenous iron is frequently administered to dialysis patients and we sought to investigate this mode of administration in transplant recipients after noticing less anaemia in several patients who had received intravenous iron just prior to being called in for transplantation.
Methods
This study is a single-centre, prospective, open-label, randomised, controlled trial of oral versus intravenous iron supplements in renal transplant recipients and aims to recruit approximately 100 patients over a 12-month period. Patients will be randomised to receive a single dose of 500 mg iron polymaltose (intravenous iron group) or 2 ferrous sulphate slow-release tablets daily (oral iron group). The primary outcome is time to normalisation of haemoglobin post-transplant. Prospective power calculations have indicated that a minimum of 48 patients in each group would have to be followed up for 3 months in order to have a 90% probability of detecting a halving of the time to correction of haemoglobin levels to ≥110 g/l in iron-treated patients, assuming an α of 0.05. All eligible adult patients undergoing renal transplantation at the Princess Alexandra Hospital will be offered participation in the trial. Exclusion criteria will include iron overload (transferrin saturation >50% or ferritin >800 μg/l), or previous intolerance of either oral or intravenous iron supplements.
Discussion
If the trial shows a reduction in the time to correction of anaemia with intravenous iron or less side effects than oral iron, then intravenous iron may become the standard of treatment in this patient group.
doi:10.1186/1471-2369-10-14
PMCID: PMC2701932  PMID: 19500381

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