Terry Feest

Survival of patients from South Asian and Black populations starting renal replacement therapy in England and Wales

Background. South Asian and Black ethnic minorities in the UK have higher rates of acceptance onto renal replacement therapy (RRT) than Caucasians. Registry studies in the USA and Canada show better survival; there are few data in the UK. Methods. Renal Association UK Renal Registry data were used to compare the characteristics and survival of patients starting RRT from both groups with those of Caucasians, using incident cases accepted between 1997 and 2006. Survival was analysed by multivariate Coxs proportional hazards regression split by haemodialysis and peritoneal dialysis (PD) due to non-proportionality, and without censoring at transplantation. Results. A total of 2495 (8.2%) were South Asian and 1218 (4.0%) were Black. They were younger and had more diabetic nephropathy. The age-adjusted prevalence of vascular co-morbidity was higher in South Asians and lower in Blacks; other co-morbidities were generally common in Caucasians. Late referral did not differ. They were less likely to receive a transplant or to start PD. South Asians and Blacks had significantly better survival than Caucasians both from RRT start to Day 90 and after Day 90, and for those on HD or PD at Day 90. Fully adjusted hazard ratios after Day 90 on haemodialysis were 0.70 (0.55–0.89) for South Asians and 0.56 (0.41–0.75) for Blacks. Conclusion. South Asian and Black minorities have better survival on dialysis. An understanding of the mechanisms may provide general insights for all patients on RRT.

Renal Chloride Channel, CLCN5, Mutations in Dent's Disease

Dents disease is an X‐linked renal tubular disorder characterized by low‐molecular‐weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, and renal failure. Patients with Dents disease may also suffer from rickets and other features of the renal Fanconi Syndrome. Patients may have mutations in the X‐linked renal chloride channel gene, CLCN5, which encodes a 746‐amino‐acid protein with 12–13 transmembrane domains. We have investigated the 11 coding exons of CLCN5 for mutations in eight unrelated patients with Dents disease. Leukocyte DNA was used for the polymerase chain reaction amplification of CLCN5 and the products analyzed for single‐stranded conformational polymorphisms (SSCPs). Abnormal SSCPs were sequenced and revealed eight mutations. These consisted of three nonsense mutations (Arg34Stop, Arg648Stop, Arg704Stop), four deletions involving codons 40, 86, 157, and 241, and one acceptor splice consensus sequence mutation tgcag → tgaag. The mutations were confirmed either by restriction endonuclease or sequence‐specific oligonucleotide hybridization analysis. In addition, an analysis of 110 alleles from 74 unrelated normal individuals demonstrated that the DNA sequence changes were not common polymorphisms. All of the mutations predict truncated chloride channels that are likely to result in a functional loss. Thus, our findings expand the spectrum of CLCN5 mutations associated with Dents disease and the results will help to elucidate further the functional domains of this novel chloride channel.

UK Renal Registry 13th Annual Report (December 2010): Chapter 2: UK RRT prevalence in 2009: national and centre-specific analyses.

Introduction: This chapter describes the characteristics of adult patients on renal replacement therapy (RRT) in the UK in 2009. The prevalence rates per million population (pmp) were calculated for Primary Care Trusts in England, Health and Social Care Areas in Northern Ireland, Local Health Boards in Wales and Health Boards in Scotland. These areas will be referred to in this report as ‘PCT/HBs’. Methods: Data were electronically collected from all 72 renal centres within the UK. A series of cross-sectional and longitudinal analyses were performed to describe the demographics of prevalent RRT patients in 2009 at centre and national level. Age and gender standardised ratios for prevalence rates in PCT/HBs were calculated. Results: There were 49,080 adult patients receiving RRT in the UK on 31st December 2009, equating to a UK prevalence of 794 pmp. This represented an annual increase in prevalent numbers of approximately 3.2% although there was significant variation between centres and PCT/HB areas. The growth rate from 2008 to 2009 for prevalent patients by treatment modality in the UK was 4.2% for haemodialysis (HD), a fall of 7.2% for peritoneal dialysis (PD) and a growth of 4.4% with a functioning transplant. There has been a slow but steady decline in the proportion of PD patients from 2000 onwards. Median RRT vintage was 5.4 years. The median age of prevalent patients was 57.7 years (HD 65.9 years, PD 61.2 years and transplant 50.8 years). For all ages, prevalence rates in males exceeded those in females: peaks for males were in the 75–79 years age group at 2,632 pmp and for females in the 70–74 years age group at 1,445 pmp. The most common identifiable renal diagnosis was biopsy-proven glomerulonephritis (16.0%), followed by diabetes (14.7%). Transplantation was the most common treatment modality (48%), HD in 44% and PD 8%. However, HD was increasingly common with increasing age and transplantation less common. Conclusions: The HD and transplant population continued to expand whilst the PD population contracted. There were national, regional and dialysis centre level variations in prevalence rates. This has implications for service planning and ensuring equity of care for RRT patients.

Chapter 6 Survival and causes of death of UK adult patients on renal replacement therapy in 2010: national and centre-specific analyses.

Introduction: These analyses examine a) survival from the start of renal replacement therapy (RRT), based on the total incident UK RRT population reported to the UK Renal Registry, including the 18% who started on PD and the 7% who received a pre-emptive transplant and b) survival of prevalent patients. Changes in survival between 1997 and 2009 are also reported. Methods: Survival of incident patients (starting RRT during 2009) was calculated both from the start of RRT and from 90 days after starting RRT, both with and without censoring at transplantation. Survival of prevalent dialysis patients was calculated to exclude patients once they were transplanted. Both Kaplan-Meier and Cox adjusted models were used to calculate survival. Causes of death were analysed for both groups. Relative risk of death was calculated compared with the general UK population. Results: The 2009 unadjusted 1 year after 90 day survival for patients starting RRT was 86.6% (87.3% in 2008). In incident patients aged 18–64, the unadjusted 1 year survival had increased from 86.0% in 1997 to 91.3% in 2009. In incident patients aged 565, unadjusted 1 year survival had improved from 64.1% to 76.2%. There were no survival differences between genders. The relative risk of death compared to the general population decreased from 25 times at age 30–34 to 2.7 times at age 85þ. Cause of death data completeness has improved 18% since last year. Cardiac disease is the most common cause of death in prevalent dialysis patients and malignancy most frequent in prevalent transplant patients. Conclusions: Survival of patients starting RRT has improved for all ages since 1997. The frequency of cardiac disease as the cause of death has decreased since 1997.

UK Renal Registry 13th Annual Report (December 2010): Chapter 1: UK RRT incidence in 2009: national and centre-specific analyses.

Introduction: This chapter describes the characteristics of adult patients starting renal replacement therapy (RRT) in the UK in 2009 and the acceptance rates for RRT in Primary Care Trusts and Health Boards (PCT/HBs) in the UK. Methods: The basic demographics and clinical characteristics are reported on patients starting RRT from all UK renal centres. Late presentation, defined as time between first being seen by a nephrologist and start of RRT being <90 days was also studied. Age and gender standardised ratios for acceptance rates in PCT/HBs were calculated. Results: In 2009, the incidence rate in the UK and England was 109 per million population (pmp). Acceptance rates in Scotland (104 pmp), Northern Ireland (88 pmp) and Wales (120 pmp) had all fallen although Wales still remained the country with the highest acceptance rate. There were wide variations between PCT/HBs with respect to the standardised ratios. The median age of all incident patients was 64.8 years (IQR 50.8, 75.1). For transplant centres this was 63.0 years (IQR 49.0, 74.2) and for non-transplanting centres 66.3 years (IQR 52.6, 75.9). The median age for non-Whites was 57.1 years. Diabetic renal disease remained the single most common cause of renal failure (25%). By 90 days, 69.1% of patients were on haemodialysis, 17.7% on peritoneal dialysis, 6.7% had had a transplant and 6.5% had died or stopped treatment. The mean eGFR at the start of RRT was 8.6 ml/min/1.73 m2 which was similar to the previous two years. Late presentation (<90 days) has fallen from 27% in 2004 to 19% in 2009. There was no relationship between social deprivation and presentation pattern. Conclusions: Acceptance rates have fallen in Northern Ireland, Scotland and Wales whilst they have plateaued in England over the last four years. Wales continued to have the highest acceptance rate of the countries making up the UK.

British renal registry is fully electronic

Editor—In his editorial on clinical databases Black did not mention the UK Renal Registry,1 although it may be the most innovative and ambitious registry in the United Kingdom. The registry was established by the Renal Association in collaboration with the British Transplant Society and the British Association of Paediatric Nephrology, and it received priming support from …

UK Renal Registry 13th Annual Report (December 2010): Chapter 4: comorbidities and current smoking status amongst patients starting renal replacement therapy in England, Wales and Northern Ireland from 2008 to 2009.

Introduction: Comorbidity is an important determinant of survival for renal replacement therapy patients and impacts other care processes such as dialysis access creation and transplant wait-listing. The prevalence of comorbidities in incident patients on renal replacement therapy (RRT) changes with age and varies between ethnic groups. This study describes these associations and the independent effect of comorbidities on outcomes. Methods: Incident patients reported to the UK Renal Registry (UKRR) with comorbidity data in 2008 and 2009 (n = 5,617) were included in analyses exploring the association of comorbidity with patient demographics, treatment modality, haemoglobin and renal function at start of RRT. For analyses examining comorbidity and survival, adult patients starting RRT between 2004 and 2009 in centres reporting to the UKRR with comorbidity data (n = 16,527) were included. The relationship between comorbidities and mortality at 90 days and one year after 90 days from start of RRT was explored using Cox regression. Results: Completeness of comorbidity data was 44.4% in 2009 compared with 52.1% in 2004. Of patients with data, 56.5% had one or more comorbidities. Diabetes mellitus and ischaemic heart disease were the most common conditions seen in 32.9% and 22.5% of patients respectively. Current smoking was recorded for 12.4% of incident RRT patients in the 2-year period. The presence of comorbidities in patients <75 years became more common with increasing age in all ethnic groups. In multivariable survival analysis, malignancy and the presence of ischaemic/neuropathic ulcers were the strongest independent predictors of poor survival at 1 year after 90 days from the start of RRT in patients <65 years. Conclusion: Differences in prevalence rates of comorbid illnesses in incident RRT patients may reflect variation in access to health care or competing risk prior to commencing treatment. The interpretation of analyses continues to be limited by poor data completeness.

UK Renal Registry 13th Annual Report (December 2010): Chapter 9: haemoglobin, ferritin and erythropoietin amongst UK adult dialysis patients in 2009: national and centre-specific analyses.

Background: The UK Renal Association (RA) and National Institute for Health and Clinical Excellence (NICE) have published Clinical Practice Guidelines which include recommendations for management of anaemia in established renal failure. Aims: To determine the extent to which the guidelines for anaemia management are met in the UK. Methods: Quarterly data were obtained regarding haemoglobin (Hb) and factors that influence Hb from renal centres in England, Wales, Northern Ireland (EWNI) and the Scottish Renal Registry for the incident and prevalent renal replacement therapy (RRT) cohorts for 2009. Results: In the UK, in 2009 55% of patients commenced dialysis therapy with Hb x10.0 g/dl (median Hb 10.2 g/dl). The median Hb of haemodialysis (HD) patients was 11.6 g/dl with an interquartile range (IQR) of 10.6 – 12.4 g/dl. Of HD patients 85% had Hb ≧10.0 g/dl. The median Hb of peritoneal dialysis (PD) patients in the UK was 11.7 g/dl (IQR 10.7–12.6 g/dl). Of UK PD patients, 88% had Hb ≧10.0 g/dl. The median ferritin in HD patients in EWNI was 441 mg/L (IQR 289–629) and 96% of HD patients had a ferritin ≧100 mg/L. The median ferritin in PD patients was 249 mg/L (IQR 142–412) with 86% of PD patients having a ferritin 5100 mg/L. In EWNI the mean Erythropoietin Stimulating Agent (ESA) dose was higher for HD than PD patients (9,507 vs. 6,212 IU/week). Conclusions: In 2009, 56% of prevalent HD patients had a Hb ≧10.5 and ≤12.5 g/dl compared with 54% in 2008 and 53% in 2007. Fifty-four percent of prevalent PD patients had a Hb ≧10.5 and ≤12.5 g/dl compared to 55% in 2008.

Chapter 2: UK RRT Prevalence in 2009: National and Centre-Specific Analyses

Introduction: This chapter describes the characteristics of adult patients on renal replacement therapy (RRT) in the UK in 2009. The prevalence rates per million population (pmp) were calculated for Primary Care Trusts in England, Health and Social Care Areas in Northern Ireland, Local Health Boards in Wales and Health Boards in Scotland. These areas will be referred to in this report as ‘PCT/HBs’. Methods: Data were electronically collected from all 72 renal centres within the UK. A series of cross-sectional and longitudinal analyses were performed to describe the demographics of prevalent RRT patients in 2009 at centre and national level. Age and gender standardised ratios for prevalence rates in PCT/HBs were calculated. Results: There were 49,080 adult patients receiving RRT in the UK on 31st December 2009, equating to a UK prevalence of 794 pmp. This represented an annual increase in prevalent numbers of approximately 3.2% although there was significant variation between centres and PCT/HB areas. The growth rate from 2008 to 2009 for prevalent patients by treatment modality in the UK was 4.2% for haemodialysis (HD), a fall of 7.2% for peritoneal dialysis (PD) and a growth of 4.4% with a functioning transplant. There has been a slow but steady decline in the proportion of PD patients from 2000 onwards. Median RRT vintage was 5.4 years. The median age of prevalent patients was 57.7 years (HD 65.9 years, PD 61.2 years and transplant 50.8 years). For all ages, prevalence rates in males exceeded those in females: peaks for males were in the 75–79 years age group at 2,632 pmp and for females in the 70–74 years age group at 1,445 pmp. The most common identifiable renal diagnosis was biopsy-proven glomerulonephritis (16.0%), followed by diabetes (14.7%). Transplantation was the most common treatment modality (48%), HD in 44% and PD 8%. However, HD was increasingly common with increasing age and transplantation less common. Conclusions: The HD and transplant population continued to expand whilst the PD population contracted. There were national, regional and dialysis centre level variations in prevalence rates. This has implications for service planning and ensuring equity of care for RRT patients.

Inherited Defects in Distal Tubular Acidification

Excerpt The pathognomonic defect of classic, or type I, renal tubular acidosis is an inability of the distal tubule to maintain the normal hydrogen ion gradient between tubular urine and plasma, an...