A stepped wedge cluster randomized trial of graphical surveillance of kidney function data to reduce late presentation for kidney replacement therapy.

Late presentation for kidney replacement therapy (KRT) is an important cause of avoidable morbidity and mortality. Here, we evaluated the effect of a complex intervention of graphical estimated glomerular filtration rate (eGFR) surveillance across 15% of the United Kingdom population on the rate of late presentation using data routinely collected by the United Kingdom Renal Registry. A stepped wedge cluster randomized trial was established across 19 sites with eGFR graphs generated from all routine blood tests (community and hospital) across the population served by each site. Graphs were reviewed by trained laboratory or clinical staff and high-risk graphs reported to family doctors. Due to delays outside the control of clinicians and researchers few laboratories activated the intervention in their randomly assigned time period, so the trial was converted to a quasi-experimental design. We studied 6,100 kidney failure events at 20 laboratories served by 17 main kidney units. A total of 63,981 graphs were sent out. After adjustment for calendar time there was no significant reduction in the rate of presentation during the intervention period. Therefore, implementation of eGFR graph surveillance did not reduce the rate of late presentation for KRT after adjustment for secular trends. Thus, graphical surveillance is an intervention aimed at reducing late presentation, but more evidence is required before adoption of this strategy can be recommended.

Comparative Effectiveness of Dynamic Treatment Strategies for Medication Use and Dosage: Emulating a Target Trial Using Observational Data.

BACKGROUND: Availability of detailed data from electronic health records (EHRs) has increased the potential to examine the comparative effectiveness of dynamic treatment strategies using observational data. Inverse probability (IP) weighting of dynamic marginal structural models can control for time-varying confounders. However, IP weights for continuous treatments may be sensitive to model choice. METHODS: We describe a target trial comparing strategies for treating anemia with darbepoetin in hemodialysis patients using EHR data from the UK Renal Registry 2004 to 2016. Patients received a specified dose (microgram/week) or did not receive darbepoetin. We compared 4 methods for modeling time-varying treatment: (A) logistic regression for zero dose, standard linear regression for log dose; (B) logistic regression for zero dose, heteroscedastic linear regression for log dose; (C) logistic regression for zero dose, heteroscedastic linear regression for log dose, multinomial regression for patients who recently received very low or high doses; and (D) ordinal logistic regression. RESULTS: For this dataset, method (C) was the only approach that provided a robust estimate of the mortality hazard ratio (HR), with less-extreme weights in a fully weighted analysis and no substantial change of the HR point estimate after weight truncation. After truncating IP weights at the 95th percentile, estimates were similar across the methods. CONCLUSIONS: EHR data can be used to emulate target trials estimating the comparative effectiveness of dynamic strategies adjusting treatment to evolving patient characteristics. However, model checking, monitoring of large weights, and adaptation of model strategies to account for these is essential if an aspect of treatment is continuous.

Increasing numbers and improved overall survival of patients on kidney replacement therapy over the last decade in Europe: an ERA Registry study.

BACKGROUND: The aim of this study was to describe the trends in the incidence, prevalence and survival of patients on kidney replacement therapy (KRT) for end-stage kidney disease (ESKD) across Europe from 2008 to 2017. METHODS: Data from renal registries in 9 countries and 16 regions that provided individual patient data to the ERA Registry from 2008 to 2017 were included. These registries cover 34% of the general population in Europe. Crude and standardized incidence and prevalence per million population (pmp) were determined. Trends over time were studied using Joinpoint regression. Survival probabilities were estimated using Kaplan-Meier analysis and hazard ratios (HRs) using Cox regression analysis. RESULTS: The standardized incidence of KRT was stable [annual percentage change (APC): -1.48 (-3.15; 0.21)] from 2008 (146.0 pmp) to 2011 (141.6 pmp), followed by a slight increase [APC: 1.01 (0.43; 1.60)] to 148.0 pmp in 2017, although trends in incidence varied across countries. This increase was primarily due to a rise in the incidence of KRT in men older than 65 years. Moreover, as a cause of kidney failure, diabetes mellitus is increasing. The standardized prevalence increased from 2008 (990.0 pmp) to 2017 (1166.8 pmp) [APC: 1.82 (1.75; 1.89)]. Patient survival on KRT improved in the time period 2011-13 compared with 2008-[adjusted HR: 0.94 (0.93; 0.95)]. CONCLUSION: This study showed an overall increase in the incidence and prevalence of KRT for ESKD as well as an increase in the KRT patient survival over the last decade in Europe.

Seasonal mortality trends for hospitalised patients with acute kidney injury across England.

BACKGROUND: Incidence of acute kidney injury (AKI) is known to peak in winter months. This is likely influenced by seasonality of commonly associated acute illnesses. We set out to assess seasonal mortality trends for patients who develop AKI across the English National Health Service (NHS) and to better understand associations with patient 'case-mix'. METHODS: The study cohort included all hospitalised adult patients in England who triggered a biochemical AKI alert in 2017. We modelled the impact of season on 30-day mortality using multivariable logistic regression; adjusting for age, sex, ethnicity, index of multiple deprivation (IMD), primary diagnosis, comorbidity (RCCI), elective/emergency admission, peak AKI stage and community/hospital acquired AKI. Seasonal odds ratios for AKI mortality were then calculated and compared across individual NHS hospital trusts. RESULTS: The crude 30-day mortality for hospitalised AKI patients was 33% higher in winter compared to summer. Case-mix adjustment for a wide range of clinical and demographic factors did not fully explain excess winter mortality. The adjusted odds ratio of patients dying in winter vs. summer was 1.25 (1.22-1.29), this was higher than for Autumn and Spring vs. Summer, 1.09 (1.06-1.12) and 1.07 (1.04-1.11) respectively and varied across different NHS trusts (9 out of 90 centres outliers). CONCLUSION: We have demonstrated an excess winter mortality risk for hospitalised patients with AKI across the English NHS, which could not be fully explained by seasonal variation in patient case-mix. Whilst the explanation for worse winter outcomes is not clear, unaccounted differences including 'winter-pressures' merit further investigation.

Increasing trends in hemodialysis and living donor kidney transplantation for children and young people in the United Kingdom.

BACKGROUND: The UK Renal Registry is responsible for the national collection and reporting of data on all children receiving long-term kidney replacement therapy [KRT], including kidney transplantation. METHODS: All 13 UK pediatric nephrology centers contributed to providing individual patient data from the pediatric population incident to and prevalent to KRT as per the date 31 December 2018. Data for children aged 16-<18 years were presented separately as some were managed under adult care settings with different methods of data collection. Demographics and biochemical data, including kidney function and prevalence of cardiovascular risk factors [hypertension, hypercholesterolemia, BMI] were reported. RESULTS: Eight hundred and twenty-six children (65.4 per million age-related population [pmarp]) and 199 young people (139.4pmarp) in the United Kingdom were prevalent to KRT on 31 December 2018. Overall, the incidence of KRT during 2018 was 9.1 pmarp and 12.6 pmarp in children and young people, respectively. Congenital anomalies of the kidney and urinary tract (CAKUT) were the most prevalent primary diagnoses (52%). Living and deceased donor transplantation was the most common treatment modality (78%). Patients on dialysis had lower age standardized mean height and weight ranges recorded in comparison to transplant patients [median height z score -1.8 vs. -1.1]. 73.1% patients had one or more cardiovascular disease risk factors. CONCLUSIONS: This study highlights increasing prevalence of hemodialysis and living donor transplantation as modalities for KRT. Of those incident to KRT, the highest patient survival was seen among 8-12 years and lowest <2 years. Moreover, there was a demographic shift from Caucasian toward Asian/other ethnicity and from CAKUT to other primary kidney diseases.

Acute kidney injury identification for pharmacoepidemiologic studies: Use of laboratory electronic acute kidney injury alerts versus electronic health records in Hospital Episode Statistics.

PURPOSE: A laboratory-based acute kidney injury (AKI) electronic-alert (e-alert) system, with e-alerts sent to the UK Renal Registry (UKRR) and collated in a master patient index (MPI), has recently been implemented in England. The aim of this study was to determine the degree of correspondence between the UKRR-MPI and AKI International Classification Disease-10 (ICD-10) N17 coding in Hospital Episode Statistics (HES) and whether hospital N17 coding correlated with 30-day mortality and emergency re-admission after AKI. METHODS: AKI e-alerts in people aged ≥18 years, collated in the UKRR-MPI during 2017, were linked to HES data to identify a hospitalised AKI population. Multivariable logistic regression was used to analyse associations between absence/presence of N17 codes and clinicodemographic features. Correlation of the percentage coded with N17 and 30-day mortality and emergency re-admission after AKI were calculated at hospital level. RESULTS: In 2017, there were 301 540 adult episodes of hospitalised AKI in England. AKI severity was positively associated with coding in HES, with a high degree of inter-hospital variability-AKI stage 1 mean of 48.2% [SD 14.0], versus AKI stage 3 mean of 83.3% [SD 7.3]. N17 coding in HES depended on demographic features, especially age (18-29 years vs. ≥85 years OR 0.22, 95% CI 0.21-0.23), as well as sex and ethnicity. There was no evidence of association between the proportion of episodes coded for AKI with short-term AKI outcomes. CONCLUSION: Coding of AKI in HES is influenced by many factors that result in an underestimation of AKI. Using e-alerts to triangulate the true incidence of AKI could provide a better understanding of the factors that affect hospital coding, potentially leading to improved coding, patient care and pharmacoepidemiologic research.

Associations with kidney transplant survival and eGFR decline in children and young adults in the United Kingdom: a retrospective cohort study.

BACKGROUND: Although young adulthood is associated with transplant loss, many studies do not examine eGFR decline. We aimed to establish clinical risk factors to identify where early intervention might prevent subsequent adverse transplant outcomes. METHODS: Retrospective cohort study using UK Renal Registry and UK Transplant Registry data, including patients aged < 30 years transplanted 1998-2014. Associations with death-censored graft failure were investigated with multivariable Cox proportional hazards. Multivariable linear regression was used to establish associations with eGFR slope gradients calculated over the last 5 years of observation per individual. RESULTS: The cohort (n = 5121, of whom n = 371 received another transplant) was 61% male, 80% White and 36% had structural disease. Live donation occurred in 48%. There were 1371 graft failures and 145 deaths with a functioning graft over a 39,541-year risk period. Median follow-up was 7 years. Fifteen-year graft survival was 60.2% (95% CI 58.1, 62.3). Risk associations observed in both graft loss and eGFR decline analyses included female sex, glomerular diseases, Black ethnicity and young adulthood (15-19-year and 20-24-year age groups, compared to 25-29 years). A higher initial eGFR was associated with less risk of graft loss but faster eGFR decline. For each additional 10 mL/min/1.73m2 initial eGFR, the hazard ratio for graft loss was 0.82 (95% CI 0.79, 0.86), p < 0.0001. However, compared to < 60 mL/min/1.73m2, higher initial eGFR was associated with faster eGFR decline (> 90 mL/min/1.73m2; - 3.55 mL/min/1.73m2/year (95% CI -4.37, - 2.72), p < 0.0001). CONCLUSIONS: In conclusion, young adulthood is a key risk factor for transplant loss and eGFR decline for UK children and young adults. This study has an extended follow-up period and confirms common risk associations for graft loss and eGFR decline, including female sex, Black ethnicity and glomerular diseases. A higher initial eGFR was associated with less risk of graft loss but faster rate of eGFR decline. Identification of children at risk of faster rate of eGFR decline may enable early intervention to prolong graft survival.

An Organizational-Level Program of Intervention for AKI: A Pragmatic Stepped Wedge Cluster Randomized Trial.

BACKGROUND: Variable standards of care may contribute to poor outcomes associated with AKI. We evaluated whether a multifaceted intervention (AKI e-alerts, an AKI care bundle, and an education program) would improve delivery of care and patient outcomes at an organizational level. METHODS: A multicenter, pragmatic, stepped-wedge cluster randomized trial was performed in five UK hospitals, involving patients with AKI aged ≥18 years. The intervention was introduced sequentially across fixed three-month periods according to a randomly determined schedule until all hospitals were exposed. The primary outcome was 30-day mortality, with pre-specified secondary endpoints and a nested evaluation of care process delivery. The nature of the intervention precluded blinding, but data collection and analysis were independent of project delivery teams. RESULTS: We studied 24,059 AKI episodes, finding an overall 30-day mortality of 24.5%, with no difference between control and intervention periods. Hospital length of stay was reduced with the intervention (decreases of 0.7, 1.1, and 1.3 days at the 0.5, 0.6, and 0.7 quantiles, respectively). AKI incidence increased and was mirrored by an increase in the proportion of patients with a coded diagnosis of AKI. Our assessment of process measures in 1048 patients showed improvements in several metrics including AKI recognition, medication optimization, and fluid assessment. CONCLUSIONS: A complex, hospital-wide intervention to reduce harm associated with AKI did not reduce 30-day AKI mortality but did result in reductions in hospital length of stay, accompanied by improvements in in quality of care. An increase in AKI incidence likely reflected improved recognition.

Psychosocial Health and Lifestyle Behaviors in Young Adults Receiving Renal Replacement Therapy Compared to the General Population: Findings From the SPEAK Study.

RATIONALE & OBJECTIVE: Patients in late adolescence and early adulthood receiving renal replacement therapy (RRT) face disruption to normal activities, which affects well-being. We aimed to define psychosocial and lifestyle outcomes for young adults on RRT compared to the general population. STUDY DESIGN: We undertook a cross-sectional survey (the SPEAK [Surveying Patients Experiencing Young Adult Kidney Failure] Study) using validated measures and general population comparator data from the Health Survey for England and Avon Longitudinal Study of Parents and Children. Additional clinical information was obtained from the UK Renal Registry. SETTING & PARTICIPANTS: 16- to 30-year-olds receiving RRT. OUTCOMES: Psychosocial health and lifestyle behaviors. ANALYTICAL APPROACH: We compared outcomes between populations using age- and sex-adjusted regression models, weighted to account for response bias by sex, ethnicity, and socioeconomic status. Our findings were used to update recent meta-analyses. RESULTS: We recruited 976 young adults and 64% responded to the survey: 417 (71%) with kidney transplants and 173 (29%) on dialysis therapy. Compared to the general population, young adults on RRT were less likely to be in a relationship and have children and more likely to live in the family home, receive no income, and be unable to work due to health. They had poorer quality of life, worse well-being, and twice the likelihood of a psychological disturbance (OR, 2.7; 95% CI, 2.0-3.7; P<0.001). They reported less smoking, alcohol and drug abuse, and crime. In a meta-analysis, our study showed the greatest differences in quality of life compared to the general population. LIMITATIONS: Cross-sectional study design, meaning that we could not track the impact of treatment changes on the outcomes. CONCLUSIONS: This study involving a large cohort of young adult transplant recipients and dialysis patients provides evidence of worse psychosocial outcomes but more positive lifestyle behaviors in young adults on RRT compared to the age-matched general population.

The clinical epidemiology of young adults starting renal replacement therapy in the UK: presentation, management and survival using 15 years of UK Renal Registry data.

Background: Clinical epidemiology data for young adults on renal replacement therapy (RRT) are lacking. While mostly transplanted, they have an increased risk of graft loss during young adulthood. Methods: We combined the UK Renal Registry paediatric and adult databases to describe patient characteristics, transplantation and survival for young adults. We grouped patients 11-30 years of age starting RRT from 1999 to 2008 by age band and examined their course during 5 years of follow-up. Results: The cohort (n = 3370) was 58% male, 79% white and 29% had glomerulonephritis. Half (52%) started RRT on haemodialysis (HD). Most (78%) were transplanted (18% pre-emptive, 61% as second modality); 11% were not listed for transplant. Transplant timing varied by age group. The deceased:living donor kidney transplant ratio was 2:1 for 11-<16 year olds and 1:1 otherwise. Median deceased donor transplant waiting times ranged from 6 months if <16 years of age to 17 months if ≥21 years. Overall 8% died, with being on dialysis and not transplant listed versus transplanted {hazard ratio [HR] 16.6 [95% confidence interval (CI) 10.8-25.4], P < 0.0001} and diabetes versus glomerulonephritis [HR 4.03 (95% CI 2.71-6.01), P < 0.0001] increasing mortality risk. Conclusions: This study highlights the frequent use of HD and the importance of transplant listing and diabetes for young adults. More than half the young adults in our cohort started renal replacement therapy on HD. One in 10 young adults were not listed for transplant by 5 years and were ∼20 times more likely to die than those who were transplanted. Diabetes as a primary renal disease was common among young adults and associated with increased mortality. Overall, almost 1 in 10 young adults had died by 5 years from the start of RRT.

Kidney transplant outcomes from older deceased donors: a paired kidney analysis by the European Renal Association-European Dialysis and Transplant Association Registry.

As the median age of deceased kidney donors rises, updated knowledge of transplant outcomes from older deceased donors in differing donor-recipient age groups is required. Using ERA-EDTA Registry data we determined survival outcomes of kidney allografts donated from the same older deceased donor (55-70 years), and transplanted into one recipient younger and one recipient of similar age to the donor. The recipient pairs were divided into two groups: group 1; younger (median age: 52 years) and older (60 years) and group 2; younger (41 years) and older (60 years). A total of 1410 adults were transplanted during 2000-2007. Compared to the older recipients, the mean number of functioning graft years at 10 years was 6 months longer in the group 1 and group 2 younger recipients (P < 0.001). Ten-year graft survival was 54% and 40% for the group 1 younger and older recipients, and 60% and 49% for the group 2 younger and older recipients. Paired Cox regression analyses showed a lower risk of graft failure (group 1 younger; adjusted relative risk [RRa]:0.57, 95% CI:0.41-0.79, and group 2 younger; RRa:0.63, 95% CI:0.47-0.85) in younger recipients. Outcomes from older deceased donor allografts transplanted into differing donor-recipient age groups are better than previously reported. These allografts remain a valuable transplant resource, particularly for similar-aged recipients.

Validity of estimated prevalence of decreased kidney function and renal replacement therapy from primary care electronic health records compared with national survey and registry data in the United Kingdom.

BACKGROUND: Anonymous primary care records are an important resource for observational studies. However, their external validity is unknown in identifying the prevalence of decreased kidney function and renal replacement therapy (RRT). We thus compared the prevalence of decreased kidney function and RRT in the Clinical Practice Research Datalink (CPRD) with a nationally representative survey and national registry. METHODS: Among all people ≥25 years of age registered in the CPRD for ≥1 year on 31 March 2014, we identified patients with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2, according to their most recent serum creatinine in the past 5 years using the Chronic Kidney Disease Epidemiology Collaboration equation and patients with recorded diagnoses of RRT. Denominators were the entire population in each age-sex band irrespective of creatinine measurement. The prevalence of eGFR <60 mL/min/1.73 m2 was compared with that in the Health Survey for England (HSE) 2009/2010 and the prevalence of RRT was compared with that in the UK Renal Registry (UKRR) 2014. RESULTS: We analysed 2 761 755 people in CPRD [mean age 53 (SD 17) years, men 49%], of whom 189 581 (6.86%) had an eGFR <60 mL/min/1.73 m2 and 3293 (0.12%) were on RRT. The prevalence of eGFR <60 mL/min/1.73 m2 in CPRD was similar to that in the HSE and the prevalence of RRT was close to that in the UKRR across all age groups in men and women, although the small number of younger patients with an eGFR <60 mL/min/1.73 m2 in the HSE might have hampered precise comparison. CONCLUSIONS: UK primary care data have good external validity for the prevalence of decreased kidney function and RRT.

A programme to spread eGFR graph surveillance for the early identification, support and treatment of people with progressive chronic kidney disease (ASSIST-CKD): protocol for the stepped wedge implementation and evaluation of an intervention to reduce late presentation for renal replacement therapy.

BACKGROUND: Patients who start renal replacement therapy (RRT) for End-Stage Kidney Disease (ESKD) without having had timely access to specialist renal services have poor outcomes. At one NHS Trust in England, a community-wide CKD management system has led to a decline in the incident rate of RRT and the lowest percentage of patients presenting within 90 days of starting RRT in the UK. We describe the protocol for a quality improvement project to scale up and evaluate this innovation. METHODS: The intervention is based upon an off-line database that integrates laboratory results from blood samples taken in all settings stored under different identifying labels relating to the same patient. Graphs of estimated glomerular filtration rate (eGFR) over time are generated for patients <65 years with an incoming eGFR <50 ml/min/1.73 m2 and patients >65 years with an incoming eGFR <40 ml/min/1.73 m2. Graphs where kidney function is deteriorating are flagged by a laboratory scientist and details sent to the primary care doctor (GP) with a prompt that further action may be needed. We will evaluate the impact of implementing this intervention across a large population served by a number of UK renal centres using a mixed methods approach. We are following a stepped-wedge design. The order of implementation among participating centres will be randomly allocated. Implementation will proceed with unidirectional steps from control group to intervention group until all centres are generating graphs of eGFR over time. The primary outcome for the quantitative evaluation is the proportion of patients referred to specialist renal services within 90 days of commencing RRT, using data collected routinely by the UK Renal Registry. The qualitative evaluation will investigate facilitators and barriers to adoption and spread of the intervention. It will include: semi-structured interviews with laboratory staff, renal centre staff and service commissioners; an online survey of GPs receiving the intervention; and focus groups of primary care staff. DISCUSSION: Late presentation to nephrology for patients with ESKD is a source of potentially avoidable harm. This protocol describes a robust quantitative and qualitative evaluation of a quality improvement intervention to reduce late presentation and improve the outcomes for patients with ESKD.

Long-term graft outcomes and patient survival are lower posttransplant in patients with a primary renal diagnosis of glomerulonephritis.

Glomerulonephritis (GN) is the primary diagnosis in 20% to 40% of patients receiving a renal transplant. Here we studied patient survival and graft outcomes in patients with GN transplanted in the UK. UK Renal Registry data were used to analyze patient survival and graft failure in incident transplant patients between 1997 to 2009 who had a diagnosis of primary GN, in comparison to patients transplanted with adult polycystic kidney disease (APKD) or diabetes. Multivariable regression analysis adjusted for age, sex, donor type, ethnicity, donor age, time on dialysis, human leukocyte antigen mismatch, cold ischemic time, and graft failure (for patient survival). Patients were followed up through December 2012. Of 4750 patients analyzed, 2975 had GN and 1775 APKD. Graft failure was significantly higher in membranoproliferative glomerulonephritis (MPGN) type II (hazard ratio: 3.5, confidence interval: 1.9-6.6), focal segmental glomerulosclerosis (2.4, 1.8-3.2), MPGN type I (2.3, 1.6-3.3), membranous nephropathy (2.0, 1.4-2.9), and IgA nephropathy (1.6, 1.3-2.0) compared to APKD. Survival was significantly reduced in patients with MPGN type II (4.7, 2.0-10.8), and those with lupus nephritis (1.8, 1.1-2.9). Overall graft failure for patients with GN was similar to those with diabetes. Thus, in comparison to outcomes in APKD, graft survival is significantly lower in most GNs, with variation in outcomes between different GNs. This information should assist in pretransplant counseling of patients. Further study is required to understand the reduced survival seen in lupus nephritis and MPGN type II, and to improve overall graft outcomes.

Glycated hemoglobin and risk of death in diabetic patients treated with hemodialysis: a meta-analysis.

BACKGROUND: Studies investigating the association between glycated hemoglobin (HbA1c) level and mortality risk in diabetic patients receiving hemodialysis have shown conflicting results. STUDY DESIGN: We conducted a systematic review and meta-analysis using MEDLINE, EMBASE, Web of Science, and the Cochrane Library. SETTING & POPULATION: Diabetic patients on maintenance hemodialysis therapy. SELECTION CRITERIA FOR STUDIES: Observational studies or randomized controlled trials investigating the association between HbA1c values and mortality risk. Study authors were asked to provide anonymized individual patient data or reanalyze results according to a standard template. PREDICTOR: Single measurement or mean HbA1c values. Mean HbA1c values were calculated using all individual-patient HbA1c values during the follow-up period of contributing studies. OUTCOME: HR for mortality risk. RESULTS: 10 studies (83,684 participants) were included: 9 observational studies and one secondary analysis of a randomized trial. After adjustment for confounders, patients with baseline HbA1c levels ≥ 8.5% (≥ 69 mmol/mol) had increased mortality (7 studies; HR, 1.14; 95% CI, 1.09-1.19) compared with patients with HbA1c levels of 6.5%-7.4% (48-57mmol/mol). Likewise, patients with a mean HbA1c value ≥ 8.5% also had a higher adjusted risk of mortality (6 studies; HR,1.29; 95% CI, 1.23-1.35). There was a small but nonsignificant increase in mortality associated with mean HbA1c levels ≤ 5.4% (≤ 36 mmol/mol; 6 studies; HR, 1.09; 95% CI, 0.89-1.34). Sensitivity analyses in incident (≤ 90 days of hemodialysis) and prevalent patients (>90 days of hemodialysis) showed a similar pattern. In incident patients, mean HbA1c levels ≤ 5.4% also were associated with increased mortality risk (4 studies; HR, 1.29; 95% CI, 1.23-1.35). LIMITATIONS: Observational study data and inability to adjust for diabetes type in all studies. CONCLUSIONS: Despite concerns about the utility of HbA1c measurement in hemodialysis patients, high levels (≥ 8.5%) are associated with increased mortality risk. Very low HbA1c levels (≤ 5.4%) also may be associated with increased mortality risk.

Ambient heat and acute kidney injury: case-crossover analysis of 1 354 675 automated e-alert episodes linked to high-resolution climate data.

BACKGROUND: As global temperatures continue to rise, the effects of ambient heat on acute kidney injury (AKI) are of growing concern. We used a novel nationwide electronic alert (e-alert) system to detect increases in AKI risk associated with high temperatures. METHODS: We used a case-crossover design to link 1 354 675 AKI episodes occurring in England between April and September in years 2017-2021 to daily maximum temperature data at postcode sector level. AKI episode data were obtained from the UK Renal Registry. There were no further inclusion or exclusion criteria. Conditional logistic regression employing distributed lag non-linear models was used to assess odds of AKI episode on case days compared with day-of-week matched control days. Effects during heatwaves were also assessed using heat-episode analysis. FINDINGS: There were strongly increased odds of AKI episode associated with high temperatures, with odds ratio (OR) 1·623 (95% CI 1·319-1·997) on a day of temperature 32°C compared with one of 17°C, the effects being strongest on a lag of 1 day. There was an OR of 1·020 (1·019-1·020) per 1°C increase in temperature above 17°C. The odds of a heat-related AKI episode were similar between AKI stages 1 and 2, but considerably lower for stage 3 events. A 7-day heatwave in July 2021 was associated with a 28·6% increase in AKI counts (95% CI 26·5-30·7). INTERPRETATION: Heat-related AKI is a growing public health challenge. As even small changes in renal function can affect patient outcomes, susceptible individuals should be advised to take preventive measures whenever hot weather is forecast. Use of an e-alert system allows effects in milder cases that do not require secondary care to also be detected. FUNDING: National Institute for Health and Care Research (NIHR).

UK Renal Registry 15th annual report: Chapter 3 demographic and biochemistry profile of kidney transplant recipients in the UK in 2011: national and centre-specific analyses.

INTRODUCTION: National transplant registries routinely focus on centre-specific patient and graft survival rates following renal transplantation. However other outcomes such as graft function (as measured by eGFR), haemoglobin and blood pressure are also important quality of care indicators. METHODS: Renal transplant activity, incident graft survival data and donor information were obtained from NHS Blood and Transplant. Laboratory and clinical variables and prevalent survival data were obtained from the UK Renal Registry. Data were analysed separately for prevalent and one year post-transplant patients. RESULTS: The only increase in transplant activity in 2011 was the use of donors after circulatory death. The death-censored graft failure rate was similar to previous years at 2.2% and the transplant patient death rates remained stable at 2.3 per 100 patient years. There was centre variation in outcomes including eGFR and haemoglobin in prevalent and 1 year post-transplant patients. Analysis of prevalent transplants by chronic kidney disease stage showed 13.6% with an eGFR <30 ml/min/1.73 m(2) and 1.7% with an eGFR <15 ml/min/1.73 m(2). Of those with CKD stage 5T, 34% had haemoglobin concentrations <10.0 g/dl, 19.8% phosphate concentrations ≥1.8 mmol/L and 7.1% adjusted calcium concentrations ≥2.6 mmol/L. Infection (23%), malignancy (21%), and cardiac disease (16%) remained amongst the commonest causes of death in patients with a functioning renal transplant. CONCLUSION: Significant variations in clinical outcomes (unadjusted for patient-specific variables) amongst kidney transplant recipients continued to exist in the UK and may reflect differences in healthcare delivery between renal centres.

UK Renal Registry 16th annual report: chapter 3 demographic and biochemistry profile of kidney transplant recipients in the UK in 2012: national and centre-specific analyses.

INTRODUCTION: National transplant registries routinely focus on centre-specific patient and graft survival rates following renal transplantation. However other outcomes such as graft function (as measured by eGFR), haemoglobin and blood pressure are also important quality of care indicators. METHODS: Renal transplant activity, incident graft survival data and donor information were obtained from NHS Blood and Transplant. Laboratory and clinical variables and prevalent survival data were obtained from the UK Renal Registry. Data were analysed separately for prevalent and one year post-transplant patients. RESULTS: The main increase in transplant activity in 2012 was the use of donors after circulatory death. The death-censored graft failure rate was similar to previous years at 2.2% and the transplant patient death rates remained stable at 2.3 per 100 patient years. There was centre variation in outcomes including eGFR and haemoglobin in prevalent and 1 year posttransplant patients. Analysis of prevalent transplants by chronic kidney disease stage showed 13.7% with an eGFR <30 ml/min/1.73 m(2) and 1.7% with an eGFR <15 ml/min/1.73 m(2). Of those with CKD stage 5T, 33% had haemoglobin concentrations <100 g/L, 27.6% phosphate concentrations 1.7 mmol/L and 20.5% adjusted calcium concentrations 2.5 mmol/L. Infection (23%) and malignancy (20%) remained amongst the commonest causes of death in patients with a functioning renal transplant. CONCLUSIONS: Significant variations in clinical outcomes (unadjusted for patient specific variables) amongst kidney transplant recipients continued to exist in the UK and may reflect differences in healthcare delivery between renal centres.