Retha Steenkamp

UK Renal Registry 17th Annual Report: Chapter 5 Survival and Cause of Death in UK Adult Patients on Renal Replacement Therapy in 2013: National and Centre-specific Analyses.

Introduction: These analyses examine survival from the start of renal replacement therapy (RRT), based on the total incident UK dialysis population reported to the Registry, including the 21% who started on PD and the 5% who received a pre-emptive transplant. Survival of prevalent patients and changes in survival between 1997–2006 are reported. The article includes a discussion on the technical definition for the date of start of both PD and HD. Methods: Survival was calculated for both incident and prevalent patients on RRT and compared between the UK countries after adjustment for age. Survival of incident patients (starting during 2006) was calculated with and without a 90 day RRT start cut off. Survival of incident patients is shown with and without censoring at transplantation. Both the 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 2006 unadjusted 1 year after 90 day survival for patients starting RRT was 86%. In incident 18–64 year olds the unadjusted 1 year survival had risen from 85.9% in 1997 to 91.5% in 2006 and for those aged ≥ 65 it had risen from 63.8% to 72.9%. The age adjusted survival of prevalent dialysis patients rose from 85% in 2000 to 89% in 2007. Diabetic patient survival rose from 76.6% in 2000 to 84.0% in 2007. The relative risk of death on RRT compared with the general population was 30 at age 30 years compared with 3 at age 80 years. In the prevalent RRT dialysis population, cardiovascular disease accounted for 34% of deaths, infection 20% and treatment withdrawal 14%. Conclusions: Incident and prevalent patient survival on RRT in all the UK countries for all age ranges and also for patients with diabetes continued to improve. The relative risk of death on RRT compared with the general population has fallen since 2001. Death rates on dialysis in the UK remained lower than when compared with a similar aged population on dialysis in the USA.

Chronic renal failure in kidney transplant recipients. Do they receive optimum care? : Data from the UK renal registry

We report the prevalence of chronic kidney disease (CKD) and related complications in a national cohort of RTR (n = 9542), and compare this with dialysis patients. The majority of RTR were classified as having CKD stage 2T (21.6%) or 3T (57.5%) with 15.7% classified as CKD stage 4T and 3.1% as stage 5T. Only 2.1% of RTR were in CKD stage 1T. The proportion of patients with stage 4T and 5T CKD who lost their graft in the following year was 8% and 49%, respectively. The prevalence of anemia (hemoglobin <11 g/dL) increased from 4.4% in stage 1T to 51.5% in stage 5T and compared with 30% in dialysis patients (p < 0.0001). Hypertension, hyperphosphatemia, elevated Ca × PO4, raised iPTH and hypoalbuminemia rose with increasing CKD stage. For many variables, the achievement of standards was lower in stage 5T RTR than in dialysis patients. There were center differences in median estimated glomerular filtration rate and percentage of patients with hemoglobin <11 g/dL (p < 0.0001). In conclusion, many patients in stage 4T–5T have CKD‐related complications that fall below targets established for nontransplant CKD patients. They are at increased risk of graft loss. More attention needs to be paid to managing these complications and preparing these patients for a return to dialysis and/or retransplantation.

Blood Pressure and Mortality Risk on Peritoneal Dialysis

BACKGROUND The association of baseline blood pressure (BP) and mortality in incident peritoneal dialysis patients has not been adequately studied. STUDY DESIGN Cohort study. SETTING & PARTICIPANTS 2,770 patients on PD therapy at 180 days from start of renal replacement therapy in England and Wales between 1997 and 2004. PREDICTORS Systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and pulse pressure (PP) measured in the first 6 months of renal replacement therapy and other baseline demographic and laboratory variables. OUTCOMES All-cause mortality was studied using time-stratified Cox regression models (to account for nonproportionality) dividing follow-up time into 4 intervals: year 1 (days 180 to 365), years 2 to 3, years 4 to 5, and years 6+. Interactions between BP components and transplant waitlist and diabetes status were explored. RESULTS Median follow-up was 3.7 years (range, 0.1 to 9.9 years), and 1,104 deaths were observed. In fully adjusted analyses, greater SBP, DBP, MAP, and PP were associated with decreased mortality in the first year, but greater SBP and PP were associated with increased late mortality (in years 6+). However, in the subgroup of patients placed on the transplant waitlist within 6 months of starting renal replacement therapy, greater SBP, DBP, MAP, and PP were not associated with decreased mortality in the first year. LIMITATIONS Exclusion of 3,086 patients because of missing BP data. No data were available for cardiac function or antihypertensive medication. CONCLUSIONS Although greater SBP, DBP, MAP, and PP appear protective against early mortality in the overall cohort, this effect is not seen in patients registered on the national transplant waiting list within 6 months of starting renal replacement therapy.

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.

Outcomes in patients on home haemodialysis in England and Wales, 1997-2005: a comparative cohort analysis.

BACKGROUND The UK national policy promotes expansion of home haemodialysis, but there are no recent data on characteristics and outcomes of a national home haemodialysis population. METHODS We compared incident home haemodialysis patients in England and Wales (n = 225, 1997-2005) with age- and sex-matched incident peritoneal dialysis, hospital haemodialysis and satellite haemodialysis patients with follow-up until 31 December 2006. Cox regression analyses included time-dependent changes of wait-listing for transplantation (a proxy for health status), start of home haemodialysis and transplantation. RESULTS There was a median delay of 12 months between starting renal replacement therapy (RRT) and home haemodialysis. During that first year of RRT, > 50% of home haemodialysis patients were wait-listed for kidney transplantation; hospital haemodialysis patients had a lower rate of wait-listing over time [hazard ratio (HR) 0.56, 95% confidence interval (CI) 0.44-0.70; P < 0.001]. In crude analyses, there was a marked survival advantage of home haemodialysis patients compared with other modalities (log-rank P-value < 0.001). In adjusted analyses, being on home haemodialysis yielded a long-term survival benefit compared with peritoneal dialysis (HR 0.61, 95% CI 0.40-0.93), and a borderline advantage compared with hospital haemodialysis (HR 0.68, 95% CI 0.44-1.03). There was no evidence of an advantage compared with satellite haemodialysis (HR 0.94, 95% CI 0.65-1.37). CONCLUSIONS Home haemodialysis patients have better survival compared with other dialysis modalities. Some of this crude survival advantage is due to selection of a healthier patient cohort as evidenced by higher transplant wait-listing rates. The advantage over peritoneal dialysis persisted after adjustment for wait-listing and transplantation over time.

Incidence, determinants and outcome of chronic kidney disease after adult heart transplantation in the United Kingdom

Background We investigated the incidence of chronic kidney disease (CKD) in the United Kingdom heart transplant population, identified risk factors for the development of CKD, and assessed the impact of CKD on subsequent survival. Methods Data from the UK Cardiothoracic Transplant Audit and UK Renal Registry were linked for 1732 adult heart transplantations, 1996 to 2007. Factors influencing time to CKD, defined as National Kidney Foundation CKD stage 4 or 5 or preemptive kidney transplantation, were identified using a Cox proportional hazards model. The effects of distinct CKD stages on survival were evaluated using time-dependent covariates. Results A total of 3% of patients had CKD at transplantation, 11% at 1-year and more than 15% at 6 years posttransplantation and beyond. Earlier transplantations, shorter ischemia times, female, older, hepatitis C virus positive, and diabetic recipients were at increased risk of developing CKD, along with those with impaired renal function pretransplantation or early posttransplantation. Significant differences between transplantation centers were also observed. The risk of death was significantly higher for patients at CKD stage 4, stage 5 (excluding dialysis), or on dialysis, compared with equivalent patients surviving to the same time point with CKD stage 3 or lower (hazard ratios of 1.66, 8.54, and 4.07, respectively). Conclusions CKD is a common complication of heart transplantation in the UK, and several risk factors identified in other studies are also relevant in this population. By linking national heart transplantation and renal data, we have determined the impact of CKD stage and dialysis treatment on subsequent survival in heart transplant recipients.

Association Between Glycemia and Mortality in Diabetic Individuals on Renal Replacement Therapy in the U.K.

OBJECTIVE In the U.K., one-third of patients receiving treatment with dialysis have diabetes. Guidelines from organizations representing patients with renal disease or diabetes advocate tight glycemic control in patients with end-stage renal disease, despite glucose-lowering trials having excluded these patients. RESEARCH DESIGN AND METHODS Using national UK Renal Registry data, we tested whether glycemia as measured by hemoglobin (Hb) A1c (HbA1c) level is associated with death in adults with diabetes starting hemodialysis or peritoneal dialysis between 1997 and 2006, and observed for at least 6 months. Of 7,814 patients, we excluded those who had died within 6 months; had received transplants; were lost/recovered; or lacked measures of HbA1c, ethnicity, or Hb. Categorizing HbA1c measured in the first 6 months of starting dialysis as <6.5% (<48 mmol/mol), 6.5–7.4% (48–57 mmol/mol) (reference value), 7.5–8.4% (58–68 mmol/mol), and ≥8.5% (≥69 mmol/mol), we adjusted in proportional hazards models for age, sex, ethnicity, deprivation, year, dialysis type, and Hb, and tested for interactions. RESULTS Of 3,157 patients observed for a median time of 2.7 years, 1,688 died. For patients ≥60 years of age, we found no association between HbA1c and death; among younger patients, relative to those with HbA1c values 6.5–7.4%, the hazard ratio for HbA1c level 7.5–8.4% was 1.2 (95% CI 0.9–1.5), and for HbA1c level >8.5% was 1.5 (1.2–1.9). The projected difference in median survival time between younger patients with a reference HbA1c value versus >8.5% was 1 year. CONCLUSIONS In the absence of trials, and confounding notwithstanding, these observational data support improved glycemic control in younger patients prior to and during dialysis.

UK Renal Registry 16th annual report: chapter 5 comorbidities and current smoking status amongst patients starting renal replacement therapy in England, Wales and Northern Ireland from 2011 to 2012.

Introduction: Comorbidities are significant predictors of mortality and other adverse outcomes. Case-mix adjustment is integral to quality reporting, risk adjustment in clinical research, resource allocation and management of patients with comorbid conditions in day to day practice such as dialysis access formation and transplant wait-listing. This study describes the comorbidity data submitted to the UK Renal Registry (UKRR) in incident renal replacement therapy (RRT) patients and examines the association between these comorbidities and early mortality. Methods: Incident patients reported to the UKRR with comorbidity data in 2011 and 2012 (n = 7,085) were included in analyses exploring the association of comorbidities with patient demographics and treatment modality. For analyses examining the association between comorbidities and survival, adult patients starting RRT between 2007 and 2012 in centres reporting to the UKRR with comorbidity data were included. The relationship between comorbidities and mortality at 90 days and one year after 90 days from start of RRT were explored using Cox regression. Results: Completeness of comorbidity data was 55% in 2012 compared with 56% in 2007. Of patients with data, 52.9% had one or more comorbidities. Diabetes mellitus and ischaemic heart disease were the most common conditions, observed in 35% and 19% of patients respectively. Fourteen percent of incident RRT patients in the 2-year period were recorded as current smokers. The prevalence of comorbidity increased with increasing age across all ethnic groups. In multivariable survival analysis, malignancy and liver disease were strong independent predictors of poor survival at 1-year after 90 days from the start of RRT in patients <65 years. Conclusions: Continuing efforts from renal centres to improve data capture in addition to the use of data linkage and statistical techniques such as multiple imputation by the UKRR are likely to lead to enhanced case mix adjustment in the future.

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.