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, Glasgow
2. Department of Cardiology, Western Infirmary, Glasgow
Background
Patients 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.
Methods
Nineteen 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).
Results
There 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.
Conclusion
In 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 posttransplant hypertension secondary to immunosuppressant therapy.
Funding: British Heart Foundation and Darlinda’s charity for Renal Research
Conflict 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 posttransplant 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 Setting
Shona Methven, Jamie Traynor, Stuart Rodger, Western Infirmary, Glasgow
Background and Aims
Patients’ 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.
Methods
A 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.
Conclusion
Overall 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 0SF
2 Renal unit, Western Infirmary Glasgow. G11 6NT
3 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 wellsupported 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 Study
Keith 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):211217.
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. Macleod
Introduction
Despite 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.
Methods
All patients with at least one creatinine above 130mol/L in females and 150mol/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.
Results
There 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: 5578). 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).
Conclusions
The 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.
Number of biopsies PMP
200
G&C
Tay
D&G
150
A&A
Lan
Gramp
100
High
50
2002
2003
2004
2005
2006
Year
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.
Background
Current 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.
Methods
Demographic 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. Antiplatelet 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.
Results
During 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 antiplatelet 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).
Discussion
There 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. Stirling
Glasgow Royal Infirmary
Background
Pauci-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.
Method
The computerised records and case notes of all patients with a diagnosis of pauciimmune 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.
Results
There 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 19851995. Survival was similar between the two groups but the earlier cohort was
significantly younger (median age 57 vs 67 years).
Conclusion
Patients 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 6NT
2. Haematology, Western Infirmary, Glasgow, G11 6NT
Introduction
The 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.
Methods
All 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.
Results
2544 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.
Conclusion
Our 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 Surgery
Ninewells 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, Glasgow
2. 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 Foundation
Conflict of interest: none
Factors associated with survival of patients on dialysis
Lajili FA, Turner AN, Metcalfe W
Abstract
Background
Dialysis 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.
Methods
Using 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.
Results
The 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.
Conclusion
This 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
Abstract
Background
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 McFatter
Renal 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
Pain
Tiredness
Nausea
Depression
Anxious
Itch
Appetite
Wellbeing
Breathlessness
Restless Legs
Dundee
(mean  s.d.)
3.1  2.8
5.1  3.1
2.1  2.4
3.2  2.7
2.5  2.4
3.0  2.2
2.5  2.4
3.0  2.8
3.4  2.2
3.2  2.6
Davison et al
(mean  s.d.)
3.6  3.1
5.1  2.7
2.1  2.5
2.8  2.8
2.9  2.9
3.6  3.1
3.7  2.7
4.2  2.5
2.6  2.8
-
Cancer
(mean  s.d.)
4.1  4.9
3.9  4.5
2.4  4.3
3.9  4.9
5.7  4.9
3.8  4.8
5.5  4.9
4.2  3.9
-
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, 1621-1625
No 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 Patients
E 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 wellnourished 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
1
Western 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 nonsignificant 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.