A comparison between serial changes in left ventricular mass in renal transplant recipients compared to patients on dialysis therapy using cardiac magnetic resonance imaging.

Rajan K Patel1, Patrick B Mark1, Nicola Johnston2, Henry J Dargie2, Alan G Jardine1

1. Renal Unit, Western Infirmary, Glasgow2. Department of Cardiology, Western Infirmary, Glasgow

BackgroundPatients with end stage renal failure (ESRD), requiring dialysis and transplantation, have an increased risk of cardiovascular (CV) disease. Left ventricular hypertrophy (LVH) is a risk factor for CV events and death in ESRD. Renal transplantation has been associated with echocardiographic regression of LVH and reduction in CV risk. However, echocardiography has been shown to overestimate LV mass in ESRD patients. Cardiac magnetic resonance (CMR) provides more detailed, volume independent, measures of cardiac structure. We studied changes in LV mass measured by CMR after renal transplantation.

MethodsNineteen transplanted patients and 19 patients on the renal transplant waiting list underwent CMR on two separate occasions. Patients who had received a renal transplant underwent CMR scanning at least 6 months after their transplant. CMR was performed on a 1.5T scanner with LV mass index (LVMI) was calculated from short axis cines of the LV in end systole and diastole and corrected for body surface area. Change in LVMI was expressed as percentage change over time. Patients with CV events between scans (e.g. acute coronary syndrome, myocardial infarction) were excluded. All transplant patients had good renal function (Cr<150μmol/l).

ResultsThere was no significant difference in age, sex, blood pressure, LVMI, ACE/AIIR antagonism, between transplant patients and non-transplanted at the time of baseline CMR scan. There was no significant change in LVMI in patients who underwent renal transplantation and those who remained on dialysis (transplanted mean +6.14%/year, SD 12.8 vs. dialysis -2.58%/year SD 17.9 respectively; p=0.09). There were no significant changes in end diastolic volumes (transplanted median -1.19%/year, IQR -11.2,+5.4 vs. dialysis -1.64%/y; -14.5,+7.53; p=0.78) or end systolic volumes (transplanted median -5.67; IQR-13.7,+6.1 vs. dialysis -0.71 ;-30.6,+15.1;p=0.72) between the groups.

ConclusionIn this small pilot study using CMR to accurately assess LV mass, renal transplantation was not associated with a significant effect on LVMI when compared to patients who remain on the transplant waiting list. Possible explanations include previous reported improvements described with echocardiography being artefactual, small sample size, or possible post-transplant hypertension secondary to immunosuppressant therapy.

Funding: British Heart Foundation and Darlinda’s charity for Renal ResearchConflict of interest: None

Mycophenolate Mofetil Induced Villous Atrophy, Enteric Hyperoxaluria and Renal Transplant Oxalate Nephropathy

Doyle M, Pall A, Laurie M, Walsh S, Lang S & Fleming S.Departments of Renal Medicine & Pathology, Ninewells Hospital & Medical School, Dundee

A 44-year-old man with end stage renal disease due to branchio-oto-renal syndrome received a live related renal transplant. Maintenance immunosuppression regimen was tacrolimus, mycophenolate mofetil (MMF) and prednisolone. Five months post-transplant he developed frequent and loose bowel movements. The dose of MMF was reduced pending further investigations of GI tract. However this was followed by an acute decline in allograft function with transplant biopsy confirming an acute cellular rejection. This was treated with pulse methylprednisolone resulting in improvement but not a return to baseline serum creatinine. A repeat renal biopsy was therefore performed which although confirmed complete resolution of the rejection also revealed significant oxalate crystal deposition within the tubules. Hyperoxaluria was confirmed by urinary oxalate excretion of 1.49 mmol/day. An upper GI endoscopy was performed and duodenal biopsies confirmed villous atrophy. This was thought most likely to be drug-induced. MMF was discontinued. Within 3 weeks his diarrhoea had stopped and his weight improved. Six weeks after stopping the MMF urinary excretion of oxalate reduced to within normal range at 0.32 mmol/day. Progress was complicated by a further episode of more severe acute cellular rejection that proved to be steroid–resistant requiring treatment with ATG. Transplant biopsies at this stage were able to show there was no further oxalate crystal deposition. Subsequently he has remained well with stable allograft function. Repeat duodenal biopsies after 3 months confirmed complete resolution of the villous atrophy.

MMF-associated villous atrophy is recognised although as far as we are aware not previously been reported to be complicated by secondary enteric hyperoxaluria and transplant oxalate nephropathy.

EBV status and the risk of PTLD

Vik Selvarajah, Alison Almond, Sue Robertson, Chris Isles

Renal Unit, Dumfries and Galloway Royal Infirmary, Dumfries, DG1 4AP

Renal transplantation prolongs survival and improves quality of life for most patients who require renal replacement therapy. Complications include cardiovascular disease, opportunistic infections and tumours. Ebstein Barr virus (EBV), cytomegalovirus (CMV) and varicella zoster virus (VZV) can all cause serious illnesses in transplanted patients. The spectrum of illness caused by EBV ranges from an acute infectious mononucleosis-like illness to a highly malignant B cell tumour. We previously reported a patient who developed this particular complication after her second transplant in whom long term remission has been achieved by reduction in immunosuppression and the use of rituximab, a monoclonal antibody with activity against B lymphocytes. We have since undertaken a survey of the Scottish Renal Transplant Pool in order to ascertain the proportion who might be at risk of PTLD in the event that they receive a kidney from an EBV positive donor or become infected by EBV following transplantation. The results of this survey will be presented at the meeting.

An Audit of Patient Satisfaction in the Renal Transplant Clinic SettingShona Methven, Jamie Traynor, Stuart Rodger, Western Infirmary, Glasgow

Background and AimsPatients’ satisfaction in the outpatient clinic experience is dictated by a number of factors; waiting times, the facilities in the outpatient department and length and quality of the consultation itself. We present data regarding the experiences of renal transplant recipients attending the outpatient clinic in a single setting.

MethodsA questionnaire was distributed to all return patients attending a renal transplant clinic in the Western Infirmary, Glasgow for 4 consecutive weeks in May 2006. Two changes in routine practise were proposed; patients were offered a container to bring a urine sample to clinic and to have venepuncture performed while waiting to see the doctor. The audit cycle was then repeated in May 2007. The patients completed the questionnaire independently and anonymously during the visit.Results Demographic data: The mean age of respondents was 47.25 years and 40% were male. In the 2006 cohort 44% of respondents were employed, in 2007 this fell to 30%. The percentage of patients with transplants within the last year had risen concurrently from 15 to 22%. Patients attend the clinic frequently with 90% of 2007 respondents attending every three monthly or less. 32% are attending at least monthly. In the 2006 cohort 68% of patients used private transport and 74% reported travelling time >30 minutes. In 2007 private transport had fallen to 58% and 80% reported travelling time of >30 minutes.

Waiting times: Short waiting times were reported at the reception desk and for using the toilet to provide a urine sample; both cycles showed average wait <5 minutes for greater than 80% of patients. Waiting time was longer for seeing the nurse with >10 minutes waiting time being reported by 43% in the 2006 cohort and 51% in 2007, and seeing the doctor, with >10 minutes being reported by 82% and 81% respectively. There was significant improvement in waiting time to have venepuncture performed; patients waiting >10 minutes fell from 90% to 22%. This followed the change in procedure.

Areas for improvement: Identified as waiting time for seeing the nurse, seeing the doctor and venepuncture. These were the same areas where waiting times >10 minutes were common. Venepuncture was still identified as a priority despite objective improvement. In 2007 fewer patients felt waiting time to see the doctor needed to be reduced.

Patients reported high overall patient satisfaction with a mean of 88% and a median of 90%. There is support for both bringing a urine sample to clinic and having venepuncture performed while waiting to see the doctor.

ConclusionOverall patient satisfaction is high. However a number of areas for improvement have been identified. It will require input from all members of the multi-disciplinary team to achieve these improvements.

A Scottish Electronic Renal Patient Record (SERPR) - Proposal

Keith Simpson1, Colin Geddes2, Neil Turner3

1 Renal unit, Glasgow Royal Infirmary, G4 0SF2 Renal unit, Western Infirmary Glasgow. G11 6NT3 Renal unit, Royal Infirmary of Edinburgh. EH16 4SU

The benefits of electronic patient records (EPRs) are widely recognised but seldom achieved (1,2). Renal units are different. For more than forty years the specialty has used fast configurable databases from which highly tuned systems have been developed. They contribute to the care of patients and to unit organisation, measurement of resource use, training, quality improvement and research (3,4).

Most renal units have developed their own database built with common software tools eg Proton® (5). This has resulted in cherished systems that reflect local practice and promote local knowledge and expertise. It has also unfortunately caused much duplication of effort, required specific training schemes in each hospital and produced few transferable IT skills. Further we are not able to benefit from economies of scale in the provision of fast well-supported lab links, fault tolerance, the adoption of international standards or the reuse of modules to solve ubiquitous problems. First generation renal systems had to provide basic patient registration, results reporting and clinic scheduling. These functions can now be devolved to dedicated administrative systems and our task in nephrology should be to design tools that address complex clinical problems, make good safe practice the norm and encourage excellence.

A recent survey of UK renal units has produced a comprehensive list of functions currently enjoyed by renal EPRs (6) and a wish list for future systems including basic decision support, predictive modelling, access to literature and high quality pictures. Most of these functions exist in embryonic form in one of the current Scottish renal EPRs. The Inverness and Aberdeen units have recently produced details specifications so it is clear that we know what we want and given the tools, know how to get there.

The Glasgow adult renal units (WIG & GRI) are being reorganised and new ambulatory care units will open soon. A new computer system will be necessary and the units at RHSC, Monklands, Crosshouse and Dumfries will be partners in this EPR. If all renal units in Scotland collaborate quickly, we could grab the opportunity and develop a national specification which would be introduced first in the west of Scotland and would be adopted by others as soon as possible. The project would be run under the auspices of the Scottish Renal Association by a group with the necessary interest and skills and with at least one person from each parent renal unit.

A SERPR would greatly simplify the running of the Scottish Renal Registry but its main function must be to support our routine clinical work.

If the project is approved by the annual business meeting of the SRA, a working group will be formed and we will arrange an early meeting with the clinical IT lead for Scotland prior to discussion with NHS Scotland and NHS Boards.

References.1) Littlejohns P, Wyatt JC, Garvican L.

Evaluating computerised health information systems: hard lessons still to be learnt. BMJ 2003; 326(7394): 860

2) Timm SJ, Rundall TG, Vogt TM, Hsu J. Kaiser Permanente's experience of implementing an electronic medical record: a qualitative study. BMJ 2005; 331(7528): 1313-13

3) Simpson K, Gordon M.The anatomy of a clinical information system. BMJ 1998; 316(7145); 1655-1658

4) Will EJ, Richardson D, Tolman C, Bartlett C. Development and exploitation of a clinical decision support system for the management of renal anaemia. Nephrol Dial Transplant 2007; 22 Suppl 4: iv31-iv36

5) The Scottish Renal Registry website http://www.srr.scot.nhs.uk/Renal_Units/Main.htm

6)Stribling B. Service Implementation - Do Once and Share Renal Action Team 2005. http://www.renal.org/rixg/DOASrenalRpt06.pdf

The Community Prevalence of low eGFR: the Scottish Heart Health Study and the British Regional Heart StudyKeith McCullough1, Corri Black 2 and Gordon Prescott 2 on behalf of the Aberdeen Renal Research Group.1 Renal Unit, Aberdeen Royal Infirmary; 2 Public Health, University of Aberdeen

Introduction: Our understanding of the prevalence of low eGFR in unselected community populations is based on published studies carried out overseas, the most widely quoted being NHANES III in the U.S.(1); no prevalence study based on an unselected screened community sample has been reported in the U.K.Aims: We sought data from 2 large historical heart cohort studies carried out in the U.K., in which participants underwent measurement of serum creatinine as part of the baseline examination, to explore the prevalence and associated co-morbidity of low eGFR. Methods: Data was supplied by the British Regional Heart Study (BRHS) and Scottish Heart Health Study (SHHS) teams in London and Dundee. The BRHS surveyed 7735 men aged 40 to 59 years, randomly selected from the registers of one general practice in each of 24 towns across England, Wales and Scotland between 1978 and 1980; response rate was 78%(2). The SHHS/ WHO Monica Study surveyed 13067 men and women aged 25 to 70 years (87% aged 40 – 59 years) across 25 districts of Scotland, selected by random sampling from General Practice registers between1984 and 1987; response rate was 72%(3). Creatinine values were standardised to reference methods using method-specific slope and intercept equations for the assay types used, then converted into eGFR using the re-expressed version of the 4-variable MDRD equation for use with zero-biased assays. Standardised prevalence rates were based on 1981 Census figures. Results: Valid eGFRs were available for 7689 (99.4%) BRHS and 11704 (89.6%) SHHS participants. In both surveys eGFR was normally distributed; in the SHHS the normal distribution for women was shifted towards lower levels. In both surveys, amongst those with eGFR below 60, eGFR was ≥ 45 in over 90%. Based on those aged 40 to 59 years with valid eGFR, adjusted prevalence rates (95%C.I.) for eGFR < 60 and eGFR < 45 respectively were: 411 per 10000 (366 – 455) and 35 per 10000 (21 – 48) for British men; 282 per 10000 (238 – 326) and 39 per 10000 (22 – 56) for Scottish men; 851 per 10000 (755 – 928) and 59 per 10000 (38 – 81) for Scottish women. For eGFR < 60, strong cross-sectional associations with hypertension, coronary artery and stroke disease were demonstrated, but not with diabetes and deprivation score.Conclusion: The prevalence rates appear higher than in the U.S. study for this age group (1.8%) (1), even allowing for error in the creatinine standardisation methodology. This could be related to the relatively high rate of vascular disease in the U.K. at the time. The degree to which low eGFR alone at a single time point predicts progressive Chronic Kidney Disease is uncertain.

(1) Coresh J, Astor BC, Greene T, Eknoyan G, Levey AS. Prevalence of chronic kidney disease and decreased kidney function in the adult US population: Third National Health and Nutrition Examination Survey. Am.J.Kidney Dis. 2003 Jan;41(1):1-12.(2) Shaper AG, Pocock SJ, Walker M, Cohen NM, Wale CJ, Thomson AG. British Regional Heart Study: cardiovascular risk factors in middle-aged men in 24 towns. Br.Med.J.(Clin.Res.Ed) 1981 Jul 18;283(6285):179-186. (3) Smith WC, Crombie IK, Tavendale R, Irving JM, Kenicer MB, Tunstall Pedoe H. The Scottish Heart Health Study: objectives and development of methods. Health.Bull.(Edinb) 1987 Jul;45(4):211-217.

The changes in patients attending the renal clinic since the introduction of the UK CKD guidelines.Kathryn Dunne 1, Krish Gunesh 2, Darryl O’Brien 2, Colin C Geddes 1

Renal Unit, Western Infirmary Glasgow, Faculty of Medicine, University of Glasgow.

Introduction: The UK CKD guidelines and laboratory eGFR reporting were introduced in April 2006 with the main aim of improving the identification and management of cardiovascular risk of patients with eGFR<60ml/min/1.73m2. Furthermore, the guidelines recommend that the majority of patients with CKD 3 without proteinuria do not require referral to nephrology clinics. The aim of this study was to quantify the change in number, demographic and clinical features of new patients attending renal clinic before and after introduction of the UK CKD guideline.

Method: All new patients attending the Western Infirmary Renal clinic in 4 time periods (second 6 months of 2003, 2004, 2005, 2006) were identified from the electronic patient record. Age, sex, CKD stage, blood pressure (BP), urine protein:creatinine ratio (uPCR), haemoglobin, serum phosphate, and the proportion on aspirin, statins and ACE inhibitors at time of first clinic attendance were compared.

Results: Analysing the trend in the four 6 month periods of 2003, 2004, 2005, 2006, the introduction of the CKD guidelines in April 2006 was associated with an abrupt rise in absolute number (186, 204, 223 and 378 respectively), mean age (57.9, 58.9, 61.1, and 66.6 year) and proportion of females (45.7%, 47.5%, 44.4% and 57.1%). The majority of the increase was explained by the number of patients with stage 3 (70, 86, 80 and 201) and stage 4 (48, 51, 64 and 115) CKD. In patients with stage 3 CKD mean systolic BP at presentation across the four year periods was 148, 146, 149 and 146 mmHg, median uPCR was 26, 26, 26 and 17mg/mmol, the proportion of patients on Aspirin was 21.1%, 39.8%, 41.3% and 41.9%, the proportion of patients on a statin was 23.9%, 38.6%, 43.8% and 51.7% and the proportion of patients on ACE inhibitors or ARBs was 28%, 38.6%, 32.5% and 44.3%. In new patients with stage 4 CKD mean systolic BP was 153, 149, 152 and 151 mmHg, median uPCR was 45, 60, 58 and 31mg/mmol, the proportion of patients on Aspirin was 35.4%, 33.3%, 46.1% and 33.9%, the proportion of patients on a statin 47.9%, 41.2%, 49.2% and 41.7% and the proportion of patients on ACE inhibitors or ARBs was 33.3%, 29.4%, 20% and 40%.

Conclusion:

The data show that the introduction of the UK CKD guidelines in April 2006 was associated with an abrupt 58.9% increase in new patients seen in the renal clinic and that the majority of the increase was explained by patients with stage 3 and 4 CKD. The median uPCR of patients with CKD 3 was, surprisingly, lower in 2006. There was evidence of increasing effort to reduce cardiovascular risk in patients with CKD in primary care before referral but no improvement in blood pressure at presentation.

Title Mild kidney disease is not an independent risk factor for mortality: findings from the Grampian CKD Study Group.Laura E. Clark, Nicholas Fluck, William Simpson, W.Cairns C.Smith, Gordon J Prescott, Alison M. MacleodIntroductionDespite the rising prevalence of early CKD the epidemiology and in particular its outcomes and natural history have not been fully explored. The Grampian CKD study aims to determine the prevalence of CKD in individuals with at least one creatinine elevated creatinine and assess their co-morbidity and outcomes in terms of survival and progression. The aim of this presentation is to focus mainly on the survival data.

MethodsAll patients with at least one creatinine above 130mol/L in females and 150mol/L in males between 1st Jan to 30th June 2003 were identified. Patients were grouped according to whether they had ARF, ACRF, CKD or on RRT. 1918 patients were initially unclassified, as they did not fulfil the strict definition for CKD (3 elevated creatinines spaced one month apart). Using more robust methodology (combining all available creatinine data together with identifying the presence of markers of kidney damage) a further group of patients with CKD were identified from the unclassified cohort. Patients were categorised as No CKD if median eGFRs greater than 60mls/min/1.73m2 and no marker present. Survival was determined as time to death from time of Index creatinine. Kaplan Meier survival curves were performed comparing survival in CKD versus No CKD followed by Cox Regression analysis to identify any independent factors associated with death in these 2 groups together. Kaplan Meier curves and Cox regression was then performed to assess the influence of CKD stage and other factors on survival.

ResultsThere were 1228 patients with CKD and 129 patients with No CKD. The median age of those with CKD was 80 years (IQR: 73-85) and for No CKD 67 years (IQR: 55-78). Cox Regression analysis showed that the presence of CKD itself was not associated with an increased risk of death over those without CKD. However the presence of co-morbidities such as peripheral vascular disease, dementia and chronic liver disease were highly significant factors. Univariate analysis of survival comparing CKD stages showed a statistically significant difference (p<0.001) with the median time to death for Stage 4 2.3 years and Stage 5 0.5 years. Multivariate Cox Regression analysis demonstrated that advanced stages of CKD (4&5) were still strongly associated with increased risk of death even after adjusting for co-morbidity (HR 1.27;CI 1.02-1.58; P= 0.29 and HR 2.33; CI 1.45-4.74; P=0.019 for Stage 4 and Stage 5 respectively). The presence of persistent proteinuria was also independently associated with death (HR 2.06; CI 1.35-3.14; P=0.001).

ConclusionsThe presence of CKD itself is not associated with an increased risk of death unless present in advanced stages. Other factors such as vascular co-morbidities are more strongly associated with risk of death than having CKD.

The epidemiology of native renal biopsy in Scotland 2002-2006

Emily Fraser 1, Bruce Mackinnon 1, Lynsey F Yeoman 1, Keith Simpson 1, Jonathan G Fox 1, Barbara Young 2, Stewart Fleming 3, Graham Stewart 3, Stuart Gardiner 4, Paul Brown 5, Stewart Lambie 6, Colin Geddes 1

1 Renal Unit, Glasgow Clyde and Forth Valley, 2 Pathology Dept, Western Infirmary, Glasgow, 3 Ninewells Hospital Dundee, 4 Monklands District General Hospital, Lanarkshire, 5 Aberdeen Royal Infirmary, 6 Raigmore Hospital, Inverness.

Background: Studies from other countries suggest that the incidence of renal biopsy varies between countries and different centres.

Aim: The aim of this study was to compare the incidence and demographics of adult native renal biopsy performed in renal centres in Scotland in the last 5 years.

Methods: Data on consecutive native renal biopsies performed between 2002 and 2006 were obtained from the relevant renal pathologist in the following regions, that each contain a single renal unit: Glasgow, Clyde and Forth Valley (G&C), Tayside (Tay), Lanarkshire (Lan), Ayrshire and Arran (A&A), Dumfries and Galloway (D&G), Grampian (Gramp) and Highland (High). Data obtained included the sex of the patient and age at time of biopsy. Population values for each region were obtained from the Scottish executive website, using the 2001 census.

Results: Between 2002 and 2006 there were 2364 native renal biopsies performed in these regions, an average of 472.8 per year (450-504). The study covers 75.1% (3,800,816) of the Scottish population, equating to an average of 126.8 biopsies per million population (PMP)/yr (120.2-134.2). The average incidence of biopsy PMP/yr per region was G&C 97.3 (89.3 – 116.8), D&G 115.1 (81.2-128.6), A&A 115.7 (84.2-165.7), Lan 121.6 (90.5-137.5), High 160.7 (128.0-195.9), Gramp 163.2 (154.0-190.2) and Tay 170.7 (144.0-192.8).

On average 56.8% of biopsies per year were performed on males, varying from 43.9% (D&G) to 62.5% (Lan). Mean age was 55.4 years, varying from 54.3 in A&A to 59.4 in D&G.

Conclusions: Further research is required to determine if the large differences in incidence of native renal biopsy in Scotland reflect true geographical differences in disease incidence or variations in nephrologist practice.

Is It Necessary to Discontinue Anti-Platelet Agents and Check Bleeding Time Before Native Renal Biopsy?

Bruce Mackinnon,1 Emily Fraser,2 Keith Simpson,1 Jonathan G. Fox,1

Colin Geddes.2

1 Renal Unit, Glasgow Royal Infirmary. 2 Renal Unit, Western Infirmary, Glasgow.

BackgroundCurrent guidelines suggest the correction of a prolonged bleeding time and discontinuation of anti-platelet agents before elective renal biopsy to reduce the risk of bleeding. The aim of the current study was to review bleeding complications following renal biopsy in two centres with different policies regarding anti-platelet agents.

MethodsDemographic and clinical data, from all patients undergoing native renal biopsy between January 2000 and May 2007 at two renal units in Glasgow were extracted from the electronic patient record. All biopsies were undertaken by a nephrologist under direct ultrasound guidance using a spring-loaded device. Bleeding time was not measured prior to biopsy and pro-coagulants were not routinely administered. Anti-platelet agents were stopped 5 days prior to biopsy in one centre but continued in the other. Haemoglobin was measured on the day of biopsy and on the following day. Major bleeding was defined as need for blood transfusion, surgical or radiological intervention. Minor bleeding was defined as >1.0g/dL fall in haemoglobin following biopsy without the need for transfusion or intervention.

ResultsDuring the period studied 1145 native renal biopsies were performed, 57% were elective procedures 60% were in males and mean age was 56.0 (± 16.8) years. Haemoglobin decreased by ≥ 1.0 g/dL in 216 (19.7%) patients. There were 21 (1.9%) major bleeding complications: 18 (1.6%) required blood transfusion and 2 patients (0.2%) underwent angiography, one of whom required embolisation of the lower pole of the kidney. No patient died or required nephrectomy. Gender, advancing age or worse renal impairment was not associated with an increased likelihood of bleeding.

When comparing the 75 patients who had elective renal biopsy while continuing to take anti-platelet agents with the 60 patients who discontinued their prescribed anti-platelet agent 5 days before elective renal biopsy there was no difference in the rate of major complications but a significantly higher proportion of patients who experienced ≥1.0g/dL reduction in haemoglobin after the biopsy in the former group (31.0 v 11.7%; p=0.008).

DiscussionThere is an extremely low risk of major bleeding following native renal biopsy under ultrasound guidance. Our data suggest that bleeding time need not be measured and anti-platelet agents need not be discontinued before renal biopsy.

Age is the strongest predictor of patient outcome in pauci-immune renal vasculitis

K.K. Stevens, S.K. McManus, P.B. Mark, J.G. Fox & C. StirlingGlasgow Royal Infirmary

BackgroundPauci-immune renal vasculitis is an important cause of end stage renal failure in the UK, often affecting elderly patients who have a particularly poor prognosis. Without treatment, patient survival is poor (20% at 1 year). This study looked at the factors which predict outcome.

MethodThe computerised records and case notes of all patients with a diagnosis of pauci-immune renal vasculitis at the Glasgow Royal and Stobhill Hospitals during the 11 year period from 1996 to 2006 were reviewed. Patient age, serum creatinine, ANCA, MPO/PR3 status, and laboratory parameters (Hb, WBC count, platelet count, CRP, serum albumin) at presentation were recorded. Treatment regimes, related complications and the need for renal replacement therapy were noted.

ResultsThere were 70 patients with pauci-immune renal vasculitis, with a median age of 66.7 years (range 15-85 years). 54% were male and 94% were ANCA positive. Sixty four had renal biopsy evidence of pauci-immune renal vasculitis and 6 had non-renal histology of small vessel vasculitis with clinical indicators of renal involvement. 38% required dialysis at presentation. Median serum creatinine at diagnosis was 415 μmol/L (58-1280).Overall patient survival (± standard error) at 1 year and 5 years was 68.5% (±5%) and 49% (±7%) respectively. Sepsis was the major cause of death (54% of those who died). Patients with cytoplasmic ANCA associated disease did significantly better than those with perinuclear ANCA associated disease with 1 year survival 81% (±6%) vs 55.2% (±9%) and 5 year survival 74% (±8%) vs 21.9% (±9%). Univariate analysis identified age, serum creatinine, Hb and ANCA status at presentation as predictors of mortality at 1 year. Multivariate analysis using binary logistic regression analysis showed age to be the only significant determinant of survival at 1 year. Cox regression analysis confirmed increasing age as a predictor of poor prognosis and also found serum creatinine at presentation, Hb and WBC count but not ANCA status to be significant covariates.Data were compared with that of a previous cohort of patients from our unit in 1985-1995. Survival was similar between the two groups but the earlier cohort was significantly younger (median age 57 vs 67 years).

ConclusionPatients presenting to our unit with pauci-immune vasculitis are increasingly elderly. Increasing age is the strongest predictor of poor patient survival. Any improvement in prognosis over the last ten years could be masked by increasing patient age.

Myeloma in CKD. Audit of Glasgow Renal Clinic screening using Serum Electrophoeresis

Doyle A1, Soutar R2, Geddes C1

1. Renal Unit, Western Infirmary, Glasgow, G11 6NT2. Haematology, Western Infirmary, Glasgow, G11 6NT

IntroductionThe incidence of Myeloma has increased in Scotland over the last 20 years. Median survival from diagnosis is 2.3 years and approximately 25% of cases present directly to renal services.

Serum electrophoeresis is commonly included in the diagnostic screening tests performed in patients with reduced kidney function. We examined the use of serum electrophoeresis in the population presenting to renal outpatient services in North Glasgow.

MethodsAll new patient attendances at general nephrology clinics in the Glasgow Renal Units along with clinical data were retrieved from the electronic patient records. All serum electrophoeresis requests and results for the period August 2004 to July 2006 were identified from Biochemistry and Immunology Laboratory Services.

Results2544 new patients attended a renal clinic for the first time1 myeloma was identified in this period in the Glasgow Renal Units of whom 1608 (63.2%) had serum electrophoeresis tested. Subjects who had electrophoeresis requested tended to be older, with higher proteinuria and lower estimated glomerular filtration rate (eGFR). 1 patient with myeloma was identified; the diagnosis was clinically apparent before the serum electrophoeresis result was requested. A further 40 subjects had abnormal serum eletrophoeresis with paraprotein concentration of less than 20g/l; none of these patients have subsequently developed myeloma. This prevalence of MGUS of 2.5% in the cohort who were tested is consistent with the expected prevalence in the general population.

ConclusionOur data suggest that serum electrophoeresis in patients with reduced kidney function or proteinuria is not a useful screening test to identify myeloma.

High prevalence of renal artery stenosis with associated risk of severe acute renal failure in patients undergoing elective abdominal aortic aneurysm surgery.

Schembri N, Wakelin S, Naji M, Chakraverty S, Griffiths G, Pall A.Departments of Renal Medicine, Radiology & Vascular SurgeryNinewells Hospital & Medical School, Dundee

Objective: This study aimed to determine the prevalence and clinical significance of renal artery stenosis (RAS) in patients undergoing elective abdominal aortic aneurysm (AAA) surgery.

Methods: A two centre retrospective study over a four-year period was undertaken. Pre-operative CT scans were evaluated for the presence of RAS. Serum creatinine levels and clinical information were collated. Acute renal failure (ARF) was defined as a rise in serum creatinine of at least 50% from baseline and/or the need for renal replacement therapy (RRT).

Results: Of 148 patients undergoing elective AAA surgery, we identified 107 who were eligible for study. Significant RAS was present in 33 (30.8%). Twelve patients (36.4%) had bilateral disease. ARF was seen in 20 (18.7%) of the 107 patients and occurred in 11 of the 33 patients with RAS (33.3%) compared to 9 of 74 (12.1%) in the non-RAS group (p<0.01, chi sq=6.73, d.f. =1). RRT was required in 6 (18.2%) patients with RAS but none of the 74 patients without RAS (P<0.001, chi sq=14.25, d.f =1). Five of the 6 patients requiring RRT had bilateral RAS. There were 6 deaths overall in the group (5.6%), 3 in patients with and 3 in patients without RAS (p=N.S., chi sq=1.09, d.f. =1).

Conclusions: A high prevalence of RAS in patients undergoing elective AAA surgery is associated with an increased post-operative risk of severe ARF, particularly in patients with bilateral RAS. We advocate pre-operative identification of RAS to identify these at risk patients. However further studies are needed to determine any potential benefit from radiological intervention of RAS prior to elective AAA surgery.

Vascular function assessed with magnetic resonance imaging predicts survival in patients with advanced chronic kidney disease

Patrick B Mark1, Arthur Doyle1, John E Foster2, Henry J Dargie2, Alan G Jardine1. 1. Renal Unit, Western Infirmary, Glasgow2. Department of Cardiology, Western Infirmary, Glasgow

Increased arterial stiffness, usually measured indirectly with tonometry, is associated with mortality in patients with advanced kidney disease. Magnetic resonance imaging (MRI) allows non-invasive assessment of central arteries potentially allowing further assessment of arterial function. We investigated the relationship between central haemodynamics and outcome in patients with advanced renal failure using MRI.

A total of 144 patients with estimated glomerular filtration rate <15ml/min (120 established on dialysis) underwent non-contrast MRI scanning (Siemens 1.5T) with brachial blood pressure measured during the scan. Aortic distensibilty (AD; pressure dependent) was calculated using the formula AD=ΔAortic Volume/Aortic Volumemin*Pulse Pressure. Aortic volumetric arterial strain (VAS; non pressure dependent) was calculated as VAS=ΔAortic Volume/Aortic Volumemin. Median follow up after the scan was 24 months.

No significant differences in AD or aortic VAS existed between dialysis patients and those not on dialysis therapy. AD and VAS demonstrated a significant negative correlation with age (AD R=-0.44, p<0.001, VAS R=-0.44, p<0.001). AD and VAS were significantly reduced in diabetics (AD, p<0.01; VAS, p<0.01), patients with ischaemic heart disease (AD, p<0.05; VAS, p<0.01) and peripheral vascular disease (AD, p<0.01; VAS, p<0.05). During follow up there were 20 deaths. Patients who died had significantly lower AD (p<0.01) than survivors. In a multivariate survival analysis, diabetes (Hazard ratio HR 4.21, p<0.01), systolic blood pressure (HR 1.02, p<0.05) and AD (HR 0.14, p<0.05) were significant independent predictors of mortality. There were 12 non-fatal cardiovascular events during follow up. In a similar analysis assessing the combined cardiovascular end point of death or a vascular event, diabetes (HR 2.41, p<0.05), AD (HR 0.07, p<0.01) and aortic VAS (HR 0.26, p<0.001) were significant predictors of events.

Deranged vascular function measured with MRI correlates with cardiovascular risk factors and predicts long term outcome in uraemia. MRI measures of vascular function are potentially novel targets for intervention to reduce cardiovascular risk.

Funding: this work was funded by the British Heart FoundationConflict of interest: none

Factors associated with survival of patients on dialysis

Lajili FA, Turner AN, Metcalfe W

AbstractBackgroundDialysis patients have much higher mortality rates than the general population. The mortality of dialysis patients is already known to be highly influenced by cardiovascular disease, age, and comorbidity. We aimed to determine if the survival of patients starting dialysis in the Royal Infirmary of Edinburgh is improving.

MethodsUsing the same methodology as a study of 249 patients starting dialysis between 1997 and 2000, we studied the 183 patients who started RRT in 2003 and 2004 in the Lothian and Borders Health regions. Comorbid conditions were collected at start of dialysis using a method similar to Khan’s score; patients were assigned to risk groups based on age and the number of comorbidities. Univariate and multivariate Cox regression analyses were used to identify the independent predictors of survival.

ResultsThe recent cohort had median age 65 years (IQR 50-75) and 55% were male compared with median age 63 years in the historical cohort. 41%, 28% and 31% of recent patients were classified as high, medium and low risk respectively. The historical cohort had a higher proportion of lower risk patients with 30%, 34% and 36% in high medium and low risk groupings. 44 (24%) recent patients had diabetes, but only 19 (10.4%) patients were diagnosed with diabetic nephropathy. Mortality of the recent cohort was 7% at 90 days after starting RRT, 26% after one year and 38% after two years. In the historical cohort these figures are 9%, 21% and 37% respectively. Cardiovascular disease was the leading cause of death (40%). Multivariate analysis revealed that comorbidity group, permanent access, initial serum albumin and initial serum cholesterol were independent predictors of mortality. When all comorbid conditions were entered separately as independent factors instead of using the comorbidity score, congestive cardiac failure and malignancy were associated with mortality.

ConclusionThis study has emphasized the high mortality of patients starting RTT in the Lothian and Borders Health regions. The overall mortality rate was essentially unchanged between the two cohorts. The high risk group showed improved survival in the recent study. Severity of comorbidity is important in predicting survival of those patients.

Subjective Global Assessment is an independent predictor of survival in dialysis patients

Lajili FA, Turner AN, Elliot H, Metcalfe W

AbstractBackground

Subjective global assessment (SGA), which assesses nutritional status based on

features of the history and physical examination, can be used to estimate malnutrition

in dialysis patients, and has been shown to be predictive of poor outcomes.

Aims

A prospective study of 122 prevalent dialysis patients was originally designed to

evaluate whether biochemical and other data already collected could identify patients

with a poor SGA score without the need for the lengthy skilled assessment. We

undertook further analysis and followed this cohort for longer to see whether there

was additional value in undertaking SGA in terms of outcomes.

Method

SGA was performed by an observer unaware of the results of the objective

measurements at the beginning of the study. Numerical data including serum

albumin, urea, body mass index (BMI), mid arm muscle circumference (MAMC),

serum cholesterol, and C-reactive protein (CRP) were extracted from the renal IT

system, and comorbidity was determined from case records and scored using the Khan

method. Univariate and multivariate Cox regression was used to identify independent

predictors of survival.

Results

At 24 months 87 patients (71.3%) were alive. Cardiovascular disease was the leading

cause of death (57.1%). A univariate analysis showed that SGA was strong predictor

of patients outcome (p=0.001), the most severely malnourished patients having 25%

survival versus 80.6% for the best scores. The Cox regression model of multivariate

analysis showed that patient survival was significantly associated with age, with SGA,

CRP, and the presence of comorbid diseases at start of dialysis.

Conclusion

Significant additional information is provided by measuring SGA.

Vascular Access in Incident Haemodialysis Patients – A Prospective Rolling Audit.

Ashleigh McKelvie, Peter Taylor, Rona Lochiel, Jane Goddard, John Neary, Walaa Sawiers, Mark Garden

Department of Renal Medicine, Royal Infirmary of Edinburgh

Background: The Renal Association guidelines state that at least 65% of patients presenting more than three months before initiation of dialysis should start haemodialysis with a usable native arteriovenous fistula. Furthermore, patients should undergo fistula creation between 6 and 12 months before haemodialysis is expected to start to allow time for adequate maturation of the fistula or time for a revision procedure if the fistula fails or is inadequate for use.

Method: A rolling audit was begun in August 2003 and recorded basic demographics, the presence and function of access at the commencement of haemodialysis, the time of referral for native vascular access and the time of surgery. Data was collected on all incident haemodialysis patients at the Royal Infirmary of Edinburgh renal unit and it’s satellite units by groups of senior house officers rotating through the renal department. The data was presented at a unit audit meeting at the end of each 4 month SHO rotation. A vascular access nurse was also appointed during the audit.

Results: From August 2003 to December 2006, 296 patients commenced haemodialysis. During the 10 audit cycles, the incident functioning native vascular access rate improved from 24% to 61%, with a significant improvement following the appointment of the vascular access nurse. The average time from referral to surgery over this period of time has increased from 3.25 months to 4.3 months, possibly reflecting an improvement in the rate of referral. Native vascular access was created earlier, with the proportion of native access formed within 3 months of starting haemodialysis falling from 37% to 20%. Of those with a formed arteriovenous fistula, the proportion in whom this was functional at first dialysis has increased from 55% to 82%.

Conclusion: Although the unit has yet to achieve the Renal Association guideline targets for native vascular access, a combination of raised awareness, earlier referral and, in particular, the appointment of a vascular access co-ordinator has lead to a significant improvement.

RISK FACTORS FOR CATHETER THROMBOSIS: RESULTS OF A 2-YEAR PROSPECTIVE STUDY

Peter C Thomson*, Catherine Stirling**, Scott Morris**, Robert A Mactier**, Jamie P Traynor***

* Research Fellow in Renal Medicine, Renal Unit, Glasgow Royal Infirmary.** Consultant Nephrologist, Renal Unit, Glasgow Royal Infirmary.***Consultant Nephrologist, Renal Unit, Monklands Hospital.

Introduction

One of the most common complications of central venous catheterisation is catheter thrombosis manifest by poor haemodialysis blood flows. In this study we describe our experience of catheter failure due to poor haemodialysis blood flow and evaluate potential risk association with underlying clinical and laboratory variables in a haemodialysis cohort.

Methods

Laboratory and clinical variables were recorded at catheter insertion and the clinical course was followed up to the point of catheter removal. An outcome event was defined as removal of a central venous catheter (CVC) in response to low haemodialysis blood flows that consistently impaired effective haemodialysis delivery despite optimal anticoagulation and/or thrombolytic intervention.

Univariate analysis was used to test for association between clinical and laboratory variables and outcome. Significant univariates were then put forward for inclusion in a multivariate model to test for independent association.

Results

44,528 catheter days of observation were accumulated over a 2-year study period during which time 365 patients underwent 823 central venous catheter insertions. A total of 131 catheters were removed due to poor haemodialysis blood flow (2.94 per 1000 catheter days).

Rates of catheter removal due to poor flow were 0.98 per 1000 catheter days in the tunnelled CVC (TCVC) group, 12.3 per 1000 catheter days in the internal jugular vein non-tunnelled CVC (NTCVC) group (p<0.001), and 37.6 per 1000 catheter days in the femoral vein NTCVC group (p<0.001). Internal jugular and femoral NTCVCs exchanged over a guidewire demonstrated failure rates of 20.2 (p<0.001) and 32.3 (p<0.001) per 1000 catheter days respectively. Low haemodialysis blood flow during the first dialysis following catheter insertion (p<0.001) and elevated levels of c-reactive protein at the time of catheter insertion (p<0.001) were also significantly associated with outcome on univariate analysis.

Multivariate analysis demonstrated hazard ratios (HR) for the development of catheter failure due to poor flow with internal jugular NTCVCs of 4.65 (p<0.001), femoral NTCVCs of 9.23 (p<0.001), 5.56 (p<0.001) for internal jugular NTCVCs exchanged over a guidewire and 11.73 (p<0.001) for femoral NTCVCs exchanged over a guidewire. Elevated c-reactive protein demonstrated a HR of 1.004 (p<0.001) per unit increase in c-reactive protein.

Conclusion

There is a hierarchy of risk association with catheter failure due to poor haemodialysis blood flow across NTCVC sub-types whilst a heightened inflammatory state at the time of catheter insertion also appears to be independently associated with outcome. We recommend tunnelled central venous catheter insertion be used where possible.

Assessment of Symptom Burden in Haemodialysis Patients

Dr K Donaldson, Dr I Henderson, Dr F McFatterRenal Unit, Ninewells Hospital, Dundee DD1 9SY

Patients with established renal failure (ERF) on maintenance haemodialysis are thought to have a high symptom burden however there is little data supporting this. In oncology and HIV literature there is a clear inverse relationship between symptoms and health related quality of life which is in turn related to morbidity and mortality. Assessment of symptoms in renal patients has been restricted due to the lack of a clear and simple evaluation tool which can be understood by patients and staff and takes little time to complete.

Davison et al(1) report the validation of the Edmonton Symptom Assessment Scale(ESAS) in 507 dialysis patients and feel that, when modified, this is a valid, simple and useful method of symptom assessment in this patient population.

131 (87%) of 150 haemodialysis patients in Ninewells Hospital completed the modified ESAS form. The majority (92%) were assisted by medical staff. The form was modified to have itch and restless legs as additional specific symptoms and all were asked if they would consider review by a symptom specialist helpful. 52% were female with an average age of 64 14. Symptom results are outlined in table 1. Symptoms are ranked from 1-10, with 10 being worst possible.

Symptom Dundee(mean s.d.)

Davison et al(mean s.d.)

Cancer(mean s.d.)

Pain 3.1 2.8 3.6 3.1 4.1 4.9Tiredness 5.1 3.1 5.1 2.7 3.9 4.5Nausea 2.1 2.4 2.1 2.5 2.4 4.3Depression 3.2 2.7 2.8 2.8 3.9 4.9Anxious 2.5 2.4 2.9 2.9 5.7 4.9Itch 3.0 2.2 3.6 3.1 -Appetite 2.5 2.4 3.7 2.7 3.8 4.8Wellbeing 3.0 2.8 4.2 2.5 5.5 4.9Breathlessness 3.4 2.2 2.6 2.8 4.2 3.9Restless Legs 3.2 2.6 - -

94 (72%) of patients expressed a desire to see a specialist in symptom control management.This reveals that symptom burden in haemodialysis patients is significant and these figures are similar to those found in patients hospitalized in the palliative care setting with cancer. Further work needs to be done in assessing these patients, in particular their health related quality of life. We need to organise protocols that target symptom control in addition to involving specialists in this field.

(1) Davison et al KI (2006) 69, 1621-1625No conflicts of interest or funding.

Unexpected cyanosis in a haemodialysis patient – did someone add hydrogen peroxide to the dialysis water?

Nick Newbigging, Ewan Bell, Willis Peel, Sue Robertson, Alison Almond, Ken Donaldson and Chris Isles

Renal Unit, Departments of Biochemistry and Intensive Care, Dumfries and Galloway Royal Infirmary, Dumfries, DG1 4AP

Four dialysis patients developed methaemoglobinaemia when hydrogen peroxide was added to their water supply following the detection of Legionella bacteria in our hospital’s main water tank. Levels of methaemoglobin were 27.2, 9.0, 4.9 and 2.2% (normal less than 1%). The two most severely affected patients also became anaemic with falls in haemoglobin of 22 and 14 g/l respectively. None of the 12 patients who were dialysing with water from the Renal Unit’s water treatment plant were affected. Water supplying the water treatment plant was held in a separate tank which had not been treated with hydrogen peroxide.

Methaemoglobinaemia occurs when iron in haemoglobin is oxidised from the ferrous to ferric state. Symptoms arise because ferric iron cannot carry oxygen. A number of oxidising drugs and chemicals may be responsible for this including dapsone, chloroquine, primaquine and hydrogen peroxide. The clue to the diagnosis is the presence of central cyanosis with low SpO2 but normal SaO2 and normal PaO2. This is because the pulse oximeter detects hypoxaemia by colorimetry whereas SaO2 and PaO2 reflect the percentage of ferrous haemoglobin capable of binding oxygen.

A literature search revealed one other report of methaemoglobinaemia occurring during dialysis. The sudden occurrence of central cyanosis with low SpO2 but normal arterial gas analysis during dialysis should lead clinicians to suspect that an oxidising agent such as hydrogen peroxide has been added to the water supply.

A Retrospective Audit of Folate Deficiency in Haemodialysis PatientsE Miller-Hodges, J Goddard. Renal Unit Edinburgh

Introduction: Management of renal anaemia has improved outcomes for patients receiving haemodialysis. The main mechanism of renal anaemia is inadequate erythropoietin production, overcome by provision of synthetic erythropoietin. Folate deficiency has been implicated as a modulating factor in renal anaemia and in hyporesponsiveness to erythropoietin therapy. Folic acid is water soluble, so is therefore removed by dialysis. Routine folate replacement for dialysis patients has been the subject of some debate, but little evidence exists to support this in well-nourished dialysis patients. However, particularly amongst frequently hospitalised, and malnourished patients folate deficiency may contribute to their anaemia.

Aims: To audit the number of patients on haemodialysis achieving target Hb levels of 11 g/dl and aassess the prevalence of folate deficiency and whether this was being appropriately addressed as a cause of relative EPO resistance.

Methods: Data was extracted from the monthly dialysis audit, from PROTON and APEX (Lothian laboratory database). The initial audit was carried out in August 2006, and repeated in December 2006.

Results: 233 patients were included in August, and 246 patients in December. 82% of patients reached target Hb levels of 11g/dl by December 2006. 45% had an assessment of folate in the last 6 months. However 34% had not been checked within the last year and 11% of patients did not have a folate result since starting HD. 50% of patients were on some form of folate supplementation.

27% of patients had proven folate deficiency on their most recent assessment. Of these 63% had been appropriately commenced on treatment, but 23 patients (37%) with demonstrated folate deficiency were not on documented folate supplementation.

However, there was no evidence that patients failing to reach target Hb levels were more likely to be folate deficient. Patients requiring >150u/kg of EPO were slightly more likely to be folate deficient (30% vs. 21% in patients requiring <150u.kg).

After a period of heightened awareness of the need both to check, and replace folic acid, a re-audit was performed in December 2006. This time, of the 35 patients with newly documented folate deficiency, 24 (68%) were documented to have started treatment. However, 9 (26%) were still not documented to have started appropriate therapy. On the second audit, a more convincing association was demonstrated between high EPO doses (“EPO resistance”) and demonstrated folate deficiency.

Conclusions: Folate deficiency is common amongst dialysis patients and merits active detection and treatment, particularly amongst high risk groups, which is important not to overlook in the management of renal anaemia. Despite the presence of protocols, alternative causes of anaemia can be overlooked when managing anaemia in renal disease. There is still improvements to be made in identifying, and managing patients with folate deficiency, and in monitring their response to therapy.

A placebo controlled micronutrient intervention in renal dialysis patients: preliminary

results

Twyla Moffitt1, Peter Garrett1 and Mary Hannon-Fletcher2

1Western Renal Service, Tyrone County Hospital, Omagh and Altnagelvin Area Hospital, Derry/Londonderry, and 2Northern Ireland Centre for Food and Health, University of Ulster, Coleraine.

Chronic renal failure is associated with increased oxidative stress, reduced antioxidant activity, retention of uraemic toxins and hyperhomocysteinaemia. Oxidative stress may be aggravated by haemodialysis. The resulting damage to cellular macromolecules in endothelial cells may explain an increased risk of cardiovascular disease, cancer and infection in haemodialysis patients (cardiovascular events account for 40-50% of mortality in this patient group). To date no investigators have completed a placebo controlled long-term randomised controlled trial of comprehensive micronutrient supplementation on markers of oxidative stress and homocysteine levels while prospectively recording cardiovascular events and there are no current recommendations regarding vitamin supplementation in this patient group.

This double blind randomised placebo-controlled intervention aims to establish whether a micronutrient dietary intervention can reduce markers of oxidant stress in maintenance haemodialysis patients. After collection of baseline blood samples for plasma folate, plasma homocysteine (tHcy) and the antioxidant enzymes SOD and GPx, 14 patients were randomised to placebo (6 controls) or active micronutrient capsule (8 subjects). Blood samples were repeated at 12 weeks. Possible changes in dietary status during the study were assessed by four day food diaries using WISP (Tinuviel v3) software.

Baseline tHcy was high in 73% of participants, but SOD and GPx were low in 66% and 20% respectively. Dialysis quality and standard biochemistry and haematology did not differ between the groups, although intake of carbohydrate and folate was significantly higher in the placebo group.

78% of participants did not meet their dietary folate requirements. Dietary antioxidant intake was also low with only 57%, 7%, 29% and 7% meeting recommended daily requirements for vitamin C, copper, zinc and selenium respectively. Baseline folate intake showed a non-significant negative correlation with tHcy (p=0.179) and there were no significant correlations between either SOD or GPx and intake of antioxidants (copper, selenium, zinc, vitamin E, vitamin A or vitamin C.

At 3 months, dialysis adequacy and standard biochemistry and haematology still did not differ between the groups, although retinol intake was significantly higher in the placebo group (p=0.038). There was however a strong trend to reduction in homocysteine levels in subjects compared to controls (-7.2 ±27.9% versus +28.4 ±34.3%, p=0.053).

The elevated baseline tHcy levels in this study confirm previous work and probably reflect dietary restrictions and dialysis-related micronutrient losses, although the degree of elevation here was less than in other reported studies. The strong trend to reduction in tHcy with a trend to enhancement of antioxidant enzyme levels in treated subjects is very encouraging and may point the way to reduction in cardiovascular risk factors and enhancement of quality of life in maintenance haemodialysis patients. Planned continuation of this pilot study with augmented numbers and follow up to 36 weeks may confirm significant advantages of intervention.

This study is supported in part by an Amgen/Irish Nephrological Society Bursary.

Title: A Retrospective Audit of Outcomes in Haemodiafiltration. B Bray, A Mason, J Goddard. Renal Unit, Edinburgh.

Introduction: Haemodiafiltration (HDF) is an increasingly popular modality of outpatient renal replacement therapy (RRT). While large outcome studies are still pending, smaller studies have demonstrated improvements over haemodialysis (HD) in phosphate control, erythropoietin requirements and Beta 2 Microglobulin clearance.

Aims: We have undertaken an audit of the biochemical efficacy of this treatment in all the patients commenced on HDF in Edinburgh between April 2005 and April 2007.

Methods: HDF commenced in Edinburgh in April 2005 and, to date, 47 patients have been treated or are receiving this modality. Patients selected for HDF were all long-standing HD patients chosen because of their length of time on RRT, a low prospect of transplantation and a reasonable expectation of survival for >5years. Because of concerns about loss of water soluble vitamins, all patients were commenced on multivitamins at the time of changing to HDF. Hours on RRT were not adjusted when HDF was commenced. Data was extracted from the monthly dialysis audit. The Renal Association Dialysis guidelines were used as audit standards. In addition all patients commenced on HDF had trace metal and micronutrient and Beta 2 microglobulin assays performed every 3 months.

Results: 47 patients were included, with time on HDF varying from 3 to 18 months. Compared to their parameters on HD, patients on HDF consistently improved their dialysis adequacy as measured by URR. There were also trends in improved phosphate and PTH levels and a trend in reduced erythropoietin requirements. Additionally, compared to patients on high flux dialysis with equivalent adequacy, phosphate control and EPO requirements were better. With supplemental multivitamins, there was no evidence for significant loss of of water-soluble vitamins or trace metals. Beta 2 microglobulin levels improved modestly within 6 months of commencing HDF but did not improve further thereafter.

Conclusions: HDF achieves good adequacy and may lead to improvements in phosphate control and reduced erythropoietin usage compared to high flux dialysis. The reduction in erythropoietin usage may offset the increased cost of this treatment. However, in these patients who have been on RRT for years before commencing HDF, effects on Beta 2 microglobulin levels are modest and may not be clinically significant.