The effect of a novel, digital physical activity and emotional well-being intervention on health-related quality of life in people with chronic kidney disease: trial design and baseline data from a multicentre prospective, wait-list randomised controlled trial (kidney BEAM)

BACKGROUND

Physical activity and emotional self-management has the potential to enhance health-related quality of life (HRQoL), but few people with chronic kidney disease (CKD) have access to resources and support. The Kidney BEAM trial aims to evaluate whether an evidence-based physical activity and emotional wellbeing self-management programme (Kidney BEAM) leads to improvements in HRQoL in people with CKD.

METHODS

This was a prospective, multicentre, randomised waitlist-controlled trial, with health economic analysis and nested qualitative studies. In total, three hundred and four adults with established CKD were recruited from 11 UK kidney units. Participants were randomly assigned to the intervention (Kidney BEAM) or a wait list control group (1:1). The primary outcome was the between-group difference in Kidney Disease Quality of Life (KDQoL) mental component summary score (MCS) at 12 weeks. Secondary outcomes included the KDQoL physical component summary score, kidney-specific scores, fatigue, life participation, depression and anxiety, physical function, clinical chemistry, healthcare utilisation and harms. All outcomes were measured at baseline and 12 weeks, with long-term HRQoL and adherence also collected at six months follow-up. A nested qualitative study explored experience and impact of using Kidney BEAM.

RESULTS

340 participants were randomised to Kidney BEAM (n = 173) and waiting list (n = 167) groups. There were 96 (55%) and 89 (53%) males in the intervention and waiting list groups respectively, and the mean (SD) age was 53 (14) years in both groups. Ethnicity, body mass, CKD stage, and history of diabetes and hypertension were comparable across groups. The mean (SD) of the MCS was similar in both groups, 44.7 (10.8) and 45.9 (10.6) in the intervention and waiting list groups respectively.

CONCLUSION

Results from this trial will establish whether the Kidney BEAM self management programme is a cost-effective method of enhancing mental and physical wellbeing of people with CKD.

TRIAL REGISTRATION

NCT04872933. Registered 5th May 2021.

A multicentre prospective double blinded randomised controlled trial of intravenous iron (ferric Derisomaltose (FDI)) in Iron deficient but not anaemic patients with chronic kidney disease on functional status

BACKGROUND

Iron deficiency (ID) is common in patients with chronic kidney disease (CKD). Intravenous (IV) iron in heart failure leads to improvement in exercise capacity and improvement in quality-of-life measurements; however, data in patients with CKD are lacking.

METHODS

The Iron and the Heart Study was a prospective double blinded randomised study in non-anaemic CKD stages 3b-5 patients with ID which investigated whether 1000 mg of IV iron (ferric derisomaltose (FDI)) could improve exercise capacity in comparison to placebo measured at 1 and 3 months post infusion. Secondary objectives included effects on haematinic profiles and haemoglobin, safety analysis and quality of life questionnaires (QoL).

RESULTS

We randomly assigned 54 patients mean (SD) age for FDI (n = 26) 61.6 (10.1) years vs placebo (n = 28; 57.8 (12.9) years) and mean eGFR (33.2 (9.3) vs. 29.1 (9.6) ml/min/1.73m2) at baseline, respectively. Adjusting for baseline measurements, six-minute walk test (6MWT) showed no statistically significant difference between arms at 1 month (p = 0.736), or 3 months (p = 0.741). There were non-significant increases in 6MWT from baseline to 1 and 3 months in the FDI arm. Haemoglobin (Hb) at 1 and 3 months remained stable. There were statistically significant increases in ferritin (SF) and transferrin saturation (TSAT) at 1 and 3 months (p < 0.001). There was a modest numerical improvement in QoL parameters. There were no adverse events attributable to IV iron.

CONCLUSION

This study demonstrated a short-term beneficial effect of FDI on exercise capacity, but it was not significant despite improvements in parameters of iron status, maintenance of Hb concentration, and numerical increases in functional capacity and quality of life scores. A larger study will be required to confirm if intravenous iron is beneficial in iron deficient non-anaemic non-dialysis CKD patients without heart failure to improve the 6MWT.

TRIAL REGISTRATION

European Clinical Trials Database (EudraCT) No: 2014-004133-16 REC no: 14/YH/1209 Date First Registered: 2015-02-17 and date of end of trail 2015-05-23 Sponsor ref R1766 and Protocol No: IHI 141.

Biological variation of cardiac troponins in chronic kidney disease

Background

Patients with chronic kidney disease often have increased plasma cardiac troponin concentration in the absence of myocardial infarction. Incidence of myocardial infarction is high in this population, and diagnosis, particularly of non ST-segment elevation myocardial infarction (NSTEMI), is challenging. Knowledge of biological variation aids understanding of serial cardiac troponin measurements and could improve interpretation in clinical practice. The National Academy of Clinical Biochemistry (NACB) recommended the use of a 20% reference change value in patients with kidney failure. The aim of this study was to calculate the biological variation of cardiac troponin I and cardiac troponin T in patients with moderate chronic kidney disease (glomerular filtration rate [GFR] 30–59 mL/min/1.73 m2).

Methods and results

Plasma samples were obtained from 20 patients (median GFR 43.0 mL/min/1.73 m2) once a week for four consecutive weeks. Cardiac troponin I (Abbott ARCHITECT® i2000SR, median 4.3 ng/L, upper 99th percentile of reference population 26.2 ng/L) and cardiac troponin T (Roche Cobas® e601, median 11.8 ng/L, upper 99th percentile of reference population 14 ng/L) were measured in duplicate using high-sensitivity assays. After outlier removal and log transformation, 18 patients’ data were subject to ANOVA, and within-subject (CVI), between-subject (CVG) and analytical (CVA) variation calculated. Variation for cardiac troponin I was 15.0%, 105.6%, 8.3%, respectively, and for cardiac troponin T 7.4%, 78.4%, 3.1%, respectively. Reference change values for increasing and decreasing troponin concentrations were +60%/–38% for cardiac troponin I and +25%/–20% for cardiac troponin T.

Conclusions

The observed reference change value for cardiac troponin T is broadly compatible with the NACB recommendation, but for cardiac troponin I, larger changes are required to define significant change. The incorporation of separate RCVs for cardiac troponin I and cardiac troponin T, and separate RCVs for rising and falling concentrations of cardiac troponin, should be considered when developing guidance for interpretation of sequential cardiac troponin measurements.

Biomarkers of Tolerance in Kidney Transplantation: Are We Predicting Tolerance or Response to Immunosuppressive Treatment?

We and others have previously described signatures of tolerance in kidney transplantation showing the differential expression of B cell-related genes and the relative expansions of B cell subsets. However, in all of these studies, the index group-namely, the tolerant recipients-were not receiving immunosuppression (IS) treatment, unlike the rest of the comparator groups. We aimed to assess the confounding effect of these regimens and develop a novel IS-independent signature of tolerance. Analyzing gene expression in three independent kidney transplant patient cohorts (232 recipients and 14 tolerant patients), we have established that the expression of the previously reported signature was biased by IS regimens, which also influenced transitional B cells. We have defined and validated a new gene expression signature that is independent of drug effects and also differentiates tolerant patients from healthy controls (cross-validated area under the receiver operating characteristic curve [AUC] = 0.81). In a prospective cohort, we have demonstrated that the new signature remained stable before and after steroid withdrawal. In addition, we report on a validated and highly accurate gene expression signature that can be reliably used to identify patients suitable for IS reduction (approximately 12% of stable patients), irrespective of the IS drugs they are receiving. Only a similar approach will make the conduct of pilot clinical trials for IS minimization safe and hence allow critical improvements in kidney posttransplant management.

Associations of baseline characteristics with evolution of eGFR in a referred chronic kidney disease cohort

BACKGROUND

Currently, most chronic kidney disease (CKD) classifications identify patients at different stages of CKD but do not identify risk of progression or adverse outcome. This analysis aims to describe associations between baseline characteristics and the evolution of estimated glomerular filtration rate (eGFR) and identify threshold values for clinical parameters that maximally discriminate progression to renal replacement therapy (RRT) in a referred cohort of patients with CKD stages 3-5.

DESIGN AND METHODS

A longitudinal mixed-effect model was used to determine annualized estimated change in eGFR and classification tree analysis to identify threshold values that maximally discriminate progression to RRT.

RESULTS

A total of 1316 patients were available for analysis with median follow-up of 33 months (interquartile range 20-60). Mixed model analysis suggested that the underlying diagnoses of autosomal dominant polycystic kidney disease and diabetic nephropathy exhibited on average a 2.7 (0.3) and 0.7 (0.3) ml/min/year faster rate of decline in eGFR, respectively, compared to those patients with biopsy-proven glomerulonephritis. In the regression tree analysis, we attempted to identify threshold values for clinical parameters that maximally discriminate progression to RRT. eGFR ≤24 ml/min was the first ranked discriminator, diastolic blood pressure appeared in the second and fourth rounds, eGFR appeared again in the third round together with cholesterol and systolic blood pressure, with basal metabolic index in the fourth.

CONCLUSION

This analysis highlights risk factors for progressive kidney disease and demonstrates the variability in evolution of eGFR across the cohort as well as the importance of underlying renal disease type on the progression of CKD.

RENAL SPECIFIC SECONDARY HYPERTENSION

Chronic kidney disease (CKD) is now understood to affect over 5% of all adult patients and it conveys a risk of reduced survival in those affected. At least 80% of those patients with stages 3-5 CKD (i.e. GFR <60 ml/min) suffer with hypertension, and in most the major cause is due to pertubation of an important renal endocrine system, the renin-angiotensin-aldosterone (RAA) axis. In this article the epidemiology of renal-related hypertension and its importance in pre-disposing to the increased cardiovascular risk in renal disease are discussed. Hypertension is known to be a major cause of progressive loss of renal function in CKD, particularly because of activation of the RAA, and hence the case for blockade of this system with ACE inhibitors and Angiotensin receptor blockers is highlighted.

Accelerated total dose infusion of low molecular weight iron dextran is safe and efficacious in chronic kidney disease patients

BACKGROUND

Low molecular weight iron dextran (LMWID) is licensed for use as a total dose infusion (TDI) over 4-6 h. In order to improve patient convenience and cost-effectiveness of therapy, we investigated the safety and efficacy of adopting accelerated dosing regimens and compared this with a standard rate LMWID infusion.

METHODS

A retrospective study of patients undergoing accelerated and standard rate TDI of LMWID was conducted across three centres. A total of 1904 doses of LMWID were administered at an accelerated rate of 1 g over 1 h 40 min. This was compared with 395 patients who had standard rate infusion of 1 g LMWID over 3-4 h.

RESULTS

There were eight minor adverse events in patients receiving accelerated dose LMWID (8/1904, 0.42%) in comparison to one adverse event in patients receiving a standard regimen (1/395, 0.25%). No serious adverse events occurred. Serum haemoglobin and ferritin significantly improved in both groups.

CONCLUSION

TDI LMWID is a safe and efficacious method of iron replacement. Accelerated infusion regimen is safe and compares well with standard rate infusion regimen. Furthermore, accelerated TDI of LMWID enables greater numbers of patients to be treated and consequently there appear to be advantages for both patient and health resources.

Protection Against Nephropathy in Diabetes with Atorvastatin (PANDA): a randomized double-blind placebo-controlled trial of high- vs. low-dose atorvastatin(1)

AIMS

To compare the renal effects of low- vs. high-dose atorvastatin in patients with Type 2 diabetes mellitus and optimally managed early renal disease.

METHODS

We compared the 2-year progression of nephropathy in a double-blind randomized controlled trial of atorvastatin 80 mg/day (n = 60) vs. 10 mg/day (n = 59) in patients with Type 2 diabetes with microalbuminuria or proteinuria [mean (sd): age 64 years (10 years); HbA(1c) 7.7% (1.3%), 61 mmol/mol (10 mmol/mol); blood pressure 131/73 mmHg; renin-angiotensin system blocker use > 80%; dual blockade > 67%] recruited from diabetes clinics in Greater Manchester.

RESULTS

Over (mean) 2.1 years of follow-up, the Modification of Diet in Renal Disease estimated glomerular filtration rate declined by 3 ml min(-1) 1.73 m(-2) in the combined group. The mean (95% CI) between-group difference during follow-up was not significant [2.2 ml min(-1) 1.73 m(-2) (-1.1 to 5.4 ml min(-1) 1.73: m(-2) ), P = 0.20] after adjusting for baseline differences in renal function; positive difference favours 80 mg dose. Similarly, there was no significant difference in creatinine clearance by Cockcroft and Gault [2.5 ml/min (-2.4 to 7.3 ml/min), P = 0.32]; serum creatinine/24-h urine collections [4.0 ml/min (-4.8 to 12.7 ml/min), P = 0.38]; cystatin C (P = 0.69); or 24-h urine protein or albumin excretion (P = 0.92; P = 0.93). We recorded no significant between-group differences in deaths or adverse events.

CONCLUSIONS

In patients with Type 2 diabetes with early renal disease, we found no statistical difference in renal function between those taking high- or low-dose atorvastatin over 2 years. We cannot exclude a beneficial effect of < 1.6 ml min(-1) 1.73 m(-2) year(-1) on Modification of Diet in Renal Disease estimated glomerular filtration rate, or if blood pressure management or if renin-angiotensin system blocker use had not been optimized.

Proteinuria as a predictor of renal functional outcome after revascularization in atherosclerotic renovascular disease (ARVD)

BACKGROUND

Renal revascularization is performed in 16% of newly diagnosed patients with atherosclerotic renovascular disease (ARVD). Although there may be some improvement in hypertension control as a result of intervention, renal functional outcomes are known to vary. Pre-existing renal parenchymal injury, as manifested by proteinuria, is associated with poor functional outcome in conservatively managed ARVD patients, but this association has not been investigated in patients undergoing revascularization.

METHODS

Retrospective case note review of 83 ARVD patients who underwent renal revascularization in four centres within a renal network between 1998 and 2003 was undertaken. Amongst other parameters, baseline proteinuria was correlated with renal functional outcome post revascularization. Renal functional outcome was determined over a mean follow up of 22 months by rate of change of estimated glomerular filtration rate (eGFR) over time.

RESULTS

Univariate analysis showed that proteinuria >0.6 g/day was the only significant predictor of poor outcome after revascularization. The relationship persisted with multivariate analysis, and linear regression showed a correlation between baseline proteinuria and decline in eGFR with time (r(2) = 0.058, P = 0.039).

CONCLUSION

This study confirms that prior renal parenchymal injury, here reflected by proteinuria at baseline, is a major arbiter of renal functional outcome after renal revascularization in ARVD.

Magnetic resonance imaging: advances in the investigation of atheromatous renovascular disease

Prediction of renal functional outcome following revascularization procedures in atheromatous renovascular disease (ARVD) has remained a challenge. In considering the etiology of renal impairment, researchers have shifted their focus now from the influence of degree of renal artery stenosis (RAS) to the importance of intrinsic parenchymal damage caused by hypertension, atheroemboli, downstream cytokine and/or cholesterol crystal release, as well as indicators of tissue viability. Magnetic resonance (MR) imaging techniques and MR-based indices are able to provide a detailed assessment of the morphologic and functional aspects of the ARVD kidney. These indices look beyond "lumenology" and enable a better understanding of the parenchyma's physiology which may provide insight into predictors of outcome. This review summarizes the multipurpose benefits of MR in the assessment of ARVD.

Angioplasty and STent for Renal Artery Lesions (ASTRAL trial): rationale, methods and results so far

Atherosclerotic renovascular disease (ARVD) is a relatively common condition which may lead to progressive renal dysfunction, and eventually to end-stage renal failure. Revascularization has been used in an attempt to prevent progression of ARVD, despite a lack of evidence for a benefit on kidney function. Therefore, large-scale randomized trials are needed to determine reliably whether or not there is any worthwhile benefit. The Angioplasty and STent for Renal Artery Lesions (ASTRAL) trial comparing renal function in ARVD patients randomized to either revascularization or medical management alone was designed to provide this evidence. ASTRAL started recruiting in November 2000 and, as of the end of 2006, 731 patients have been randomized into the trial (19 patients short of its minimum target of 750 patients). A pooled analysis (not split by treatment arm) of all patients shows that serum creatinine increased in the first 6 months then remained relatively steady, whereas blood pressure has decreased from baseline. The trial is due to close to recruitment in April 2007, with the first presentation of the results of the randomized treatment comparison planned for the spring of 2008. To date ASTRAL is by far the largest randomized trial in ARVD, and will provide the most reliable and timely evidence on the role, if any, of revascularization in ARVD with which to guide the treatment of future patients.

Prevalence of hypogonadism in male patients with renal failure

BACKGROUND

Hypogonadism in men may be secondary to renal failure and is well recognised in patients with end-stage renal disease. It is thought to contribute to the sexual dysfunction and osteoporosis experienced by these patients. However, the association between hypogonadism and lesser degrees of renal dysfunction is not well characterised.

METHODS

The gonadal status of 214 male patients (mean age 56 (SD 18) years) attending a renal centre was studied; 62 of them were receiving haemodialysis and 22 continuous ambulatory peritoneal dialysis for end-stage renal disease, whereas 34 patients had functioning renal transplants and 96 patients were in the low-clearance phase. Non-fasting plasma was analysed for testosterone, follicle-stimulating hormone, luteinising hormone, sex hormone-binding globulin, parathyroid hormone and haemoglobin. Creatinine clearance was estimated in patients not on dialysis, and Kt/V and urea reduction ratio were assessed in patients on dialysis. Testosterone concentrations were classified as normal (>14 nmol/l), low-normal (10-14 nmol/l) or low (<10 nmol/l).

RESULTS

56 (26.2%) patients had significantly low testosterone levels and another 65 (30.3%) had low-normal levels. No significant changes were seen in sex hormone-binding globulin or gonadotrophin levels. Gonadal status was not correlated with haemoglobin level, parathyroid hormone level, creatinine clearance, or dialysis duration or adequacy.

CONCLUSION

Over half of patients with renal failure, even in the pre-dialysis phase, have low or low-normal levels of testosterone, which may be a potentially reversible risk factor for osteoporosis and sexual dysfunction. These patients may be candidates for testosterone-replacement therapy, which has been shown to improve bone mineral-density and libido in men with low and low-normal testosterone levels.

MR-derived renal morphology and renal function in patients with atherosclerotic renovascular disease

Appropriate selection of patients with atherosclerotic renovascular disease (ARVD) for revascularization might be improved if accurate non-invasive investigations were used to assess severity of pre-existing parenchymal damage. The purpose of this study was to evaluate the associations between magnetic resonance imaging (MRI)-measured renal morphological parameters and single-kidney glomerular filtration rate (GFR) in ARVD. Three-dimensional (3D)-MRI was performed on 35 ARVD patients. Renal bipolar length (BL), parenchymal volume, parenchymal (PT), and cortical thicknesses (CT) were measured in 65 kidneys. Thirteen kidneys were supplied by normal vessels, 13 had insignificant (<50%) renal artery stenosis (RAS), 33 significant (>or=50%) RAS, and six complete vessel occlusion. All patients underwent radioisotopic measurement of single-kidney GFR (isoSK-GFR). Overall, 3D parameters such as parenchymal volume were better correlates of isoSK-GFR (r=0.86, P<0.001) than BL (r=0.78, P<0.001), PT (r=0.63, P<0.001) or CT (r=0.60, P<0.001). Kidneys with >or=50% RAS did show significant reduction in mean CT compared to those supplied by normal vessel (5.67+/-1.63 vs 7.28+/-1.80 mm, P=0.002; 22.1% reduction) and an even greater loss of parenchymal volume (120.65+/-47.15 vs 179.24+/-86.90 ml, P<0.001; 32.7% reduction) with no significant reduction in BL. In a proportion of >or=50% RAS kidneys, a disproportionately high parenchymal volume to isoSK-GFR was observed supporting a concept of 'hibernating parenchyma'. 3D parameters of parenchymal volume are stronger correlates of isoSK-GFR than two-dimensional measures of BL, PT or CT. 3D morphological evaluation together with isoSK-GFR might be useful in aiding patient selection for renal revascularization. Kidneys with increased parenchymal volume to SK-GFR might represent a subgroup with the potential to respond beneficially to angioplasty.

Severe acute renal failure in adults: place of care, incidence and outcomes

BACKGROUND

Department of Health guidelines recommend specialist critical care facilities for patients with severe single-organ failure such as acute renal failure (ARF). Prospective studies examining incidence, causes and outcomes of ARF outside of intensive care settings are lacking.

AIM

To determine the incidence, causes, place of care and outcomes of severe single-organ ARF.

DESIGN

Prospective observational study.

METHODS

For 6 weeks in June-July 2003, renal physicians were contacted daily, and ICUs on alternate days, to identify cases of severe single-organ ARF in the Greater Manchester area. All patients with serum creatinine >or=500 micromol/l and not requiring other organ support were included. Patients with end-stage renal disease were excluded. Survivors were followed up at 90 days and 1 year from admission. Two independent consultant nephrologists assessed each case using anonymized summaries.

RESULTS

Eighty-five patients had multi-organ ARF and 28 had severe single-organ ARF (380 and 125 pmp/year, respectively). Of those with single-organ ARF, 10 (36%) had known pre-existing chronic kidney disease. Renal replacement therapy (RRT) was required in 15 (54%). Total bed occupancy on ICUs relating to single-organ ARF was 59 days (range per patient 1-21). At 90 days, 18 (64%) were alive, and 17 (94%) had independent renal function. At 1 year, 4/18 had died, none receiving RRT at the time of death. Survivors all had independent renal function. In 13 (46%) cases there was an unacceptable delay in patient transfer and in 7 (25%), delays in assessment or commencement of RRT may have adversely affected patient outcome.

DISCUSSION

The incidence of ARF treated with RRT is rising. Delays in transfer to renal services may result in inappropriate ICU bed use, and may adversely affect patient outcomes. There are serious problems regarding the appropriate use of expensive and limited medical resources in the critical care area, and in providing safe and effective treatment of patients with ARF.

The importance of associated extra-renal vascular disease on the outcome of patients with atherosclerotic renovascular disease

Atherosclerotic renovascular disease (ARVD) is a disease of ageing. It is usually a manifestation of widespread vascular disease and although it may be symptomless, many patients with ARVD present with the effects of extra-renal vascular disease, such as peripheral vascular (PVD), coronary heart (CHD) and cerebrovascular disease. ARVD is a common cause of hypertension and chronic renal failure (CRF), and it is one of the most common renal diagnoses in elderly patients accepted on to dialysis programmes with end-stage renal failure (ESRF). The cause of renal impairment in these patients is still a matter of debate. Patients with ARVD have a high mortality, especially those with renal failure. In this review we examine the relationships between ARVD and co-morbid extra-renal vascular disease, and the impact of these associated vascular pathologies upon renal functional and mortality outcomes is considered. The latest evidence concerning the likely pathogenesis of renal dysfunction in patients with ARVD is also reviewed.

Early management and prevention of acute renal failure

Despite major advances in nutritional support, membrane technology and dialytic techniques, the mortality of patients with acute renal failure (ARF) who require dialysis is still almost 50% (1). Increased patient age and co-morbidity confer a poorer prognosis, and the condition is certainly commoner in this patient group. Hence, one study showed that the age-related annual incidence of ARF increased from 17 per million in adults under 50 years to 949 per million in the 80-89 age group (2). Over 60% of cases of ARF ultimately result from renal hypoperfusion and consequent intra-renal ischaemic damage, which leads to acute tubular necrosis (ATN) (3). Ischaemic ARF may thus result from a diversity of systemic and intra-renal circulatory stresses including acute losses of blood and extra-cellular fluids, from low cardiac output states such as following ischaemic or toxic myocardial damage, and even from drug-induced renal perfusion shutdown (ACE inhibitors, non-steroidal anti-inflammatory agents). Many cases of ARF have a multi-factorial aetiology (e.g. post-surgical sepsis with hypovolaemia, hypotension and injudicious antibiotic use), and these patients, who often have other organ failure, fit into the poorer prognostic category. A large number of patients with ischaemic ARF pass through a phase of potentially reversible pre-renal oliguria; early recognition and prompt, appropriate treatment of these pre-renal factors can prevent progression to established ARF, with the genuine prospect of improved patient morbidity and mortality, and this is the main scope of this article. Early diagnosis in other patients with ARF, such as those with acute inflammatory renal disease (e.g. vasculitis) or urinary tract obstruction, will allow appropriate prompt treatment and the possibility for reversal of the ARF. The following account, which is composed of personal experience, that of colleagues, and the literature (1,4), is not intended to provide a comprehensive guide to the management of ARF, but seeks to highlight important common pitfalls and fundamental principles in the recognition and subsequent preventive treatment of these patients.

Carbamazepine-induced acute granulomatous interstitial nephritis

A 79-year-old man, newly started on carbamazepine, presented with rash, eosinophilia and liver dysfunction progressing to acute renal failure despite discontinuation of the anti-epileptic agent. Percutaneous renal biopsy revealed acute granulomatous interstitial nephritis, which responded successfully to high-dose oral steroid therapy.

Clinicopathological correlation in biopsy-proven atherosclerotic nephropathy: implications for renal functional outcome in atherosclerotic renovascular disease

BACKGROUND

Atherosclerotic renovascular disease (ARVD) is commonly associated with renal failure. It is now recognized that intrarenal damage, (ischaemic or atherosclerotic nephropathy) is a major contributor to the renal impairment in these patients. In this study the impact of histological changes upon renal functional outcome was investigated in patients with atherosclerotic nephropathy.

METHODS

The Hope Hospital renal biopsy database (1985-1998) was interrogated for patients with histology compatible with atherosclerotic nephropathy. Case-note review enabled the assessment of several clinical parameters and outcomes, including change in creatinine clearance per year (DeltaCrCl (ml/min/year)), blood pressure control, dialysis need, and death. Renal parenchymal damage was analysed by morphometric analysis (of interstitial fibrosis and glomerulosclerosis) and a semi-quantitative chronic damage score (score 0-3 (normal-severe) for each of glomerulosclerosis, interstitial fibrosis, tubular atrophy, and arteriolar hyalinosis; maximum=12). Patients were stratified into two groups who had either deteriorating (group 1) or stable (group 2) renal function during follow-up.

RESULTS

Twenty-five patients (age 64.7+/-10.5, range 43-83 years; 17 male, eight female) were identified. Sixteen patients had undergone angiography; two had significant (>50%) renal artery stenosis. Mean follow-up was 25.6+/-14.8 (range 5-50) months. Group 1 patients had DeltaCrCl -7.4+/-6.8 ml/min/year, n=14 and group 2 patients had DeltaCrCl 4.8+/-7.0 ml/min/year, n=11. Four patients in group 1 developed end-stage renal disease and five patients died (three in group 1 and two in group 2). At study entry, group 1 patients had worse renal function (CrCl 27.6+/-17.6 vs 36.0+/-33.9, NS), greater proteinuria (1.2 vs 0.5 g/24 h, NS), and higher systolic blood pressure (167.1+/-30.8 mmHg vs 150.6+/-37.8, NS) compared with group 2 patients. Group 1 patients showed more glomerulosclerosis (51.6 vs 24.9%, P:<0.01), greater proportional interstitial volume (44.9 vs 33.9%, P:<0.02), and higher overall chronic damage score (P:<0.05) than those in group 2. There was a significant correlation between renal functional outcome and chronic damage score, glomerulosclerosis and proportional interstitial volume for the entire patient cohort.

CONCLUSION

In patients with atherosclerotic nephropathy the severity of histopathological damage is an important determinant and predictor of renal functional outcome.

Isolated sarcoid granulomatous interstitial nephritis: review of five cases at one center

AIMS

To identify any clinical or biochemical parameters which determine prognostic outcome in isolated sarcoid granulomatous interstitial nephritis presenting with renal failure.

METHODS

A review of five cases of renal failure due to isolated sarcoid granulomatous interstitial nephritis, which presented to Hope Hospital over the 7-year period 1994 to 2000. Follow-up averaged 35 months with a range of 11 to 73 months.

RESULTS

Only one patient had an elevated serum ACE at presentation, reflecting the suboptimal sensitivity of this test as a marker in sarcoidosis and the limited extent of disease in these patients. Four of the five cases had a marked improvement in creatinine clearance within 10 days of starting oral prednisolone. Two patients required acute hemodialysis on presentation. Their renal failure responded to treatment with steroids, enabling withdrawal of dialysis within 10 days. All patients remained dialysis-independent although serum creatinine levels rose during follow-up. One patient experienced a relapse that responded to an increased dose of steroid.

CONCLUSIONS

Serum ACE is not reliable in the diagnosis of renal failure due to sarcoid interstitial nephritis and the diagnosis can only be made on renal biopsy. First-line treatment with oral prednisolone results in a rapid improvement in creatinine clearance although prolonged treatment may be needed to prevent a relapse.

Increasing the diagnostic yield of renal angiography for the diagnosis of atheromatous renovascular disease

Atheromatous renovascular disease (ARVD) is a common cause of hypertension and chronic renal failure (CRF). In this unit, intravenous digital subtraction angiography (DSA) (or intraarterial DSA if indicated) is used as a screening angiographic study when ARVD is suspected. However, increased use of these investigations has resulted in a longer waiting time for angiography. As the majority of studies are negative for ARVD, clinical features and results of investigations of patients undergoing angiography were reviewed to identify those having the greatest likelihood of ARVD. The clinical notes were reviewed for all 249 patients undergoing angiography over an 18-month period. Primary indications for investigation were: hypertension 71 (28.5%), CRF 156 (62.7%) and CRF with severe hypertension 22 (8.8%). 12 of the CRF patients had end-stage renal failure. 166 (66.7%) patients had no evidence of ARVD, while only 83 (33.3%) patients showed some degree of ARVD, 29 (35%) of which had bilateral renal artery disease. There was no significant difference between the ARVD group and the non-ARVD group for mean age (69.0 years vs 63.3 years), male to female ratio, history of smoking (68.7% vs 55.4%), severe hypertension (10.8% vs 9.0%), hypercholesterolaemia (61.4% vs 47.0%), diabetes mellitus (28.6% vs 25.3%) or angiotensin converting enzyme inhibitor-related renal dysfunction (9.6% vs 6.1%). More patients in the ARVD group were investigated for CRF than in the non-ARVD group, as reflected by the higher serum creatinine level and the lower creatinine clearance in the ARVD group. 55 (33.1%) of the non-ARVD patients had no comorbid vascular disease, vascular bruits or ultrasound discrepancy in the size of the two kidneys, whereas all ARVD patients had at least one of these features (negative predictive value 100%). All three features were present in 19.3% of ARVD patients but in only 3.0% of the non-ARVD patients (positive predictive value 76.2%, specificity 97%). We plan to rationalize the criteria for angiography in the light of these findings, anticipating an increase in the diagnostic yield of renal angiography from its current 33.3% to above 42%.

Changes in lipid profiles in non diabetic, non nephrotic patients commencing continuous ambulatory peritoneal dialysis

This study examined the effect on patient lipid profile of commencing continuous ambulatory peritoneal dialysis (CAPD). We followed eighteen non diabetic, non nephrotic patients for 9 months before and after dialysis commencement and compared lipid profiles. Mean cholesterol levels rose from 4.98 mmol/L to 5.42 mmol/L (p < 0.05). This change was chiefly due to a rise in low density lipoprotein (LDL) cholesterol. The LDL cholesterol rose after dialysis commencement and continued to rise up to 9 months later. High-density lipoprotein (HDL) cholesterol remained stable. Serum albumin and body weight fell during follow-up, suggesting that the rise in cholesterol was not a reflection of enhanced nutritional status. This study highlights the pro-atherogenic change in lipids that results from commencing CAPD. This phenomenon is not seen in hemodialysis, and it should be considered when selecting a dialysis modality, given the increased risk of cardiovascular disease in the dialysis population.

Relationship of renal dysfunction to proximal arterial disease severity in atherosclerotic renovascular disease

BACKGROUND

Renal impairment is common in patients with atherosclerotic renovascular disease (ARVD), but its pathogenesis is uncertain. This study investigated whether any relationship existed between renal function and the severity of proximal renal arterial lesions in patients with ARVD.

METHODS

A cohort of 71 patients had creatinine clearance measured at the time of digital subtraction angiography; eight patients were diabetics and were excluded from further analysis. The severity of proximal renovascular lesions was estimated by standard methodology, and patients were sub-grouped according to residual patency of the proximal renal arteries (e.g. normal=2.0; unilateral occlusion )RAO(=1.0). Renal bipolar lengths at ultrasound were also assessed.

RESULTS

Sixty-three non-diabetic patients (mean+/-SD age 67.7+/-5.8 years; 34 males) were suitable for study. No differences in renal function (mean+/-SD creatinine clearance (ml/min)) were seen between patients with unilateral (32. 1+/-18.9, n=36) or bilateral (31.7+/-20.9, n=27) disease, or between sub-groups with RAS <60% (28.3+/-13.9, n=15), unilateral RAS >60% (38.9+/-24.6, n=12), bilateral RAS >60% (36.3+/-20.4, n=6) or unilateral RAO (30.3+/-17.7, n=28), and mean average renal size similarly did not differ between the sub-groups. No correlation existed between residual patency and creatinine clearance (r=0.015); mean+/-SD renal function was almost identical in the four patency sub-groups, and average renal size mirrored this pattern. Mean 24-h urinary protein excretion was similar for the four groups, but patients with minimal ARVD had significantly less comorbid vascular disease.

CONCLUSIONS

These findings suggest that the severity of proximal renal artery lesions is often unrelated to the severity of renal dysfunction in patients with ARVD. Associated renal parenchymal damage is the more probable arbiter of renal dysfunction, and this should be considered when revascularization procedures are contemplated.

New insights into the epidemiologic and clinical manifestations of atherosclerotic renovascular disease

Atherosclerotic renovascular disease (ARVD) continues to challenge the clinician as we enter the third millenium. ARVD frequently complicates patients with other vascular pathological states, and it is an increasingly common cause of end-stage renal failure. Although renovascular interventional procedures are now widely available and are of benefit to some patients with ARVD, a large proportion still progress to dialysis. Recent epidemiological investigations have emphasized the relationship between ARVD and other vascular diseases, and these are notable in patients with coronary artery disease and/or cardiac failure. Increased awareness of the possible coexistence of ARVD in patients with these latter conditions may allow earlier diagnosis and a minimization of complications (eg, angiotensin-converting enzyme inhibitor-related uremia or flash pulmonary edema). Contemporary studies also highlight the importance of intrarenal vascular and parenchymal injury in the cause of chronic renal failure in many patients with ARVD. Severe renal structural damage often coexists with proximal renal arterial narrowing, and this can explain the variability of renal functional outcomes known to accompany revascularization procedures. More appropriate selection of those patients likely to benefit from renovascular revascularization is now required. Large-scale trials that will identify the optimal approach to improving renal functional and survival outcomes in this high-risk group of patients are now long overdue.

Proteinuria in atherosclerotic renovascular disease

Proteinuria is well described in atherosclerotic renovascular disease (ARVD), but the prevalence is unknown, and the pathogenesis may vary between patients. Substantial proteinuria (> 2 g/day) however, would be regarded by many as atypical of ARVD. We studied 94 patients (52 male) with ARVD, median age 67 years (range 49-87). Digital subtraction angiography was performed on all patients. Protein was assayed in 24-h urine samples and GFR derived using the Cockroft-Gault formula. Forty-nine patients (52%) had proteinuria < 0.5 g/24 h. Proteinuria increased with worsening renal function. Biopsies from seven non-diabetic patients with substantial proteinuria showed: minimal changes (1); glomerular sclerosis with marked ischaemic changes (3); focal glomerulosclerosis (2); and athero-emboli (1). Proteinuria, rather than being indicative of other pathology, is often a marker of severity of parenchymal disorder in atherosclerotic nephropathy, which itself is the major determinant of renal dysfunction in patients with ARVD.

Questionnaire study and audit of use of angiotensin converting enzyme inhibitor and monitoring in general practice: the need for guidelines to prevent renal failure

OBJECTIVES

To determine the current pattern of use of angiotensin converting enzyme inhibitor and monitoring of renal function in general practice and to audit all admissions to a regional renal unit for uraemia related to use of these drugs.

DESIGN

Postal questionnaire sent to 400 general practitioners; audit of clinical notes of all patients receiving these drugs in one large general practice; audit of all cases of uraemia (creatinine concentration >500 micromol/l) related to treatment presenting to hospital renal services over 12 months.

SETTING

General practices in the North Wales health authority and one in central Manchester. Regional renal unit in Salford.

MAIN OUTCOME MEASURES

Proportion of general practitioners who regularly monitored renal function before and after initiation of angiotensin converting enzyme inhibitors. Indications for treatment and details of monitoring of renal function in patients receiving these drugs. Incidence of related uraemia and evidence of comorbid disease, other aetiological factors, delayed detection, and patient outcome.

RESULTS

277 (69%) general practitioners replied; 235 (85%) checked renal function before but only 93 (34%) after the start of treatment, and 42 (15%) never checked renal function. Angiotensin converting enzyme inhibitors were prescribed for 162 patients from a total of 3625 aged >35 years (mean age 66.4 (SD 15.9) years). Monitoring of renal function occurred before treatment in 55 (45%) and after start of treatment in 35 (29%) of the 122 patients treated in general practice. Angiotensin converting enzyme inhibitors could be causally implicated in 9 (7%) of 135 admissions for uraemia (mean age 74.2 (7. 2) v 62.1 (2.1) years; P<0.01). 3 patients had renovascular disease and 6 had congestive cardiac failure with another intercurrent illness. Renal function had not been checked in any patient after the start of treatment; mean duration of illness before admission was 10.5 (3.2) days. Mean length of hospital stay was 20.9 (10.4) days; there were 8 survivors.

CONCLUSION

Cases of uraemia related to treatment with angiotensin converting enzyme inhibitors are still encountered and are often detected late because of lack of judicious monitoring of renal function in vulnerable, often elderly, patients, especially at times of intercurrent illness. Guidelines for appropriate monitoring of renal function may help to minimise the problem.

Risk of morbidity from renovascular disease in elderly patients with congestive cardiac failure

BACKGROUND

Renovasular disease commonly affects elderly people. Elderly patients with heart failure are routinely treated with angiotensin-converting-enzyme (ACE) inhibitors, which may increase risk of renal dysfunction. We investigated the frequency of renovascular disease among elderly people with heart failure.

METHODS

From the local population of Salford, UK, we recruited 86 patients with heart failure with a mean age of 77.5 (SD 5.6) years, who were admitted as acute emergencies or who attended general medical clinics. We selected patients by intention to treat with ACE inhibitors. We used captopril renography to screen for renovascular disease. All patients with abnormal renograms underwent magnetic-resonance angiography of the renal arteries as well as 40% of patients with normal renograms as negative controls.

FINDINGS

Magnetic-resonance angiography showed severe renovascular disease (>50% renal-artery stenosis or occlusion) in 29 (34%) patients. Captopril renography had an estimated sensitivity of 78.8% (95% CI 72.7-97.8) and specificity of 94.3% (67.6-97.3) for detection of renovascular disease. The estimated positive predictive value of captopril renography was 89.7% and the negative predictive value was 87.5%. Patients with renovascular disease had worse renal function (mean creatinine 201 [SD 56] vs 136 [40] pmol/L, p<0.001), were older (mean age 80.7 [5.6] vs 76.8 [5.3] years, p<0.01), and were more likely than patients without renovascular disease to have peripheral arterial disease.

INTERPRETATION

Some elderly patients with occult renovascular disease on ACE inhibitors will be at risk of developing uraemia. Renal function should be closely monitored to detect any deterioration early.

Nephrotic-range proteinuria associated with right atrial myxoma

A case of right atrial myxoma presenting with right heart failure and proteinuria is described. Proteinuria was variable and this corresponded with the degree of systemic venous congestion. On one occasion the proteinuria was within the nephrotic range. There was no evidence of intrinsic renal pathology. The right heart failure and proteinuria resolved after tumour removal, suggesting that the etiology of urinary protein loss was a reversible increase in glomerular permeability.