A Systematic Review of COVID-19 and Kidney Transplantation.

INTRODUCTION: Kidney transplant recipients are at increased susceptibility to many viral infections leading to justifiable anxiety about the effects of coronavirus disease 2019 (COVID-19). METHODS: We performed literature searches from multiple resources in April and August 2020 for relevant English and Chinese literature. Abstracts were screened, followed by full-text review with data extraction of reports that included at least 20 kidney transplant recipients with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and completed outcomes. RESULTS: Twenty studies had sufficient data, which we have summarized. Studies were predominantly descriptive and came from France, Italy, Spain, Turkey, United Kingdom, and United States. Quality assessment demonstrated limitations in selection of comparison groups and controlling for additional factors. Mortality rates from published studies were variable. Based on early data early from Spain, 46% of patients who developed COVID-19 within 60 days of transplantation died. Acute kidney injury was common, and mycophenolate was discontinued in most patients. CONCLUSION: Given the rapid global spread of COVID-19, reliable evidence is needed to inform public health policies. Hospitalized kidney transplant recipients with COVID-19 are at a high risk of death in early reports but interpretation of these data requires caution, as studies were susceptible to period effects. Reassuringly, the quality of observational data is improving. Detailed and comprehensive data collection through linked registries will be necessary to conduct accurate analyses of risk factors for adverse outcomes, not least given the risks of stopping imunosuppression. This report highlights the early mortality excess in transplant recipients but medium- and longer-term outcomes remain uncertain and merit careful investigation.

Assessing Consensus Between UK Renal Clinicians on Listing for Kidney Transplantation: A Modified Delphi Study.

BACKGROUND: It is well recognized that there is significant variation between centers in access to kidney transplantation. In the absence of high-grade evidence, it is unclear whether variation is due to patient case mix, other center factors, or individual clinician decisions. This study sought consensus between UK clinicians on factors that should influence access to kidney transplantation. METHODS: As part of the Access to Transplantation and Transplant Outcome Measures project, consultant nephrologists and transplant surgeons in 71 centers were invited to participate in a Delphi study involving 2 rounds. During rounds 1 and 2, participants rated their agreement to 29 statements covering 8 topics regarding kidney transplantation. A stakeholder meeting was used to discuss statements of interest after the 2 rounds. RESULTS: In total, 122 nephrologists and 16 transplant surgeons from 45 units participated in rounds 1 and 2. After 2 rounds, 12 of 29 statements reached consensus. Fifty people participated in the stakeholder meeting. After the stakeholder meeting, a further 4 statements reached agreement. Of the 8 topics covered, consensus was reached in 6: use of a transplant protocol, patient age, body mass index, patient compliance with treatment, cardiac workup, and use of multidisciplinary meetings. Consensus was not reached on screening for malignancy and use of peripheral Doppler studies. CONCLUSIONS: The Delphi process identified factors upon which clinicians agreed and areas where consensus could not be achieved. The findings should inform national guidelines to support decision making in the absence of high quality evidence and to guide areas that warrant future research.

Pharmacoepidemiology for nephrologists: do proton pump inhibitors cause chronic kidney disease?

Pharmacoepidemiology studies are increasingly used for research into safe prescribing in chronic kidney disease (CKD). Typically, patients prescribed a drug are compared with patients who are not on the drug and outcomes are compared to draw conclusions about the drug effects. This review article aims to provide the reader with a framework to critically appraise such research. A key concern in pharmacoepidemiology studies is confounding, in that patients who have worse health status are prescribed more drugs or different agents and their worse outcomes are attributed to the drugs not the health status. It may be challenging to adjust for this using statistical methods unless a comparison group with a similar health status but who are prescribed a different (comparison) drug(s) is identified. Another challenge in pharmacoepidemiology is outcome misclassification, as people who are more ill engage more often with the health service, leading to earlier diagnosis in people who are frequent attenders. Finally, using replication cohorts with the same methodology in the same type of health system does not ensure that findings are more robust. We use two recent papers that investigated the association of proton pump inhibitor drugs with CKD as a device to review the main pitfalls of pharmacoepidemiology studies and how to attempt to mitigate against potential biases that can occur.

Diagnosis and Management of Iron Deficiency in CKD: A Summary of the NICE Guideline Recommendations and Their Rationale.

The UK-based National Institute for Health and Care Excellence (NICE) has updated its guidance on iron deficiency and anemia management in chronic kidney disease. This report outlines the recommendations regarding iron deficiency and their rationale. Serum ferritin alone or transferrin saturation alone are no longer recommended as diagnostic tests to assess iron deficiency. Red blood cell markers (percentage hypochromic red blood cells, reticulocyte hemoglobin content, or reticulocyte hemoglobin equivalent) are better than ferritin level alone at predicting responsiveness to intravenous iron. When red blood cell markers are not available, a combination of transferrin saturation < 20% and ferritin level < 100ng/mL is an alternative. In comparisons of the cost-effectiveness of different iron status testing and treatment strategies, using percentage hypochromic red blood cells > 6% was the most cost-effective strategy for both hemodialysis and nonhemodialysis patients. A trial of oral iron replacement is recommended in people not receiving an erythropoiesis-stimulating agent (ESA) and not on hemodialysis therapy. For children receiving ESAs, but not treated by hemodialysis, oral iron should be considered. In adults and children receiving ESAs and/or on hemodialysis therapy, intravenous iron should be offered. When giving intravenous iron, high-dose low-frequency administration is recommended. For all children and for adults receiving in-center hemodialysis, low-dose high-frequency administration may be more appropriate.

Understanding cost of care for patients on renal replacement therapy: looking beyond fixed tariffs.

BACKGROUND: In a number of countries, reimbursement to hospitals providing renal dialysis services is set according to a fixed tariff. While the cost of maintenance dialysis and transplant surgery are amenable to a system of fixed tariffs, patients with established renal failure commonly present with comorbid conditions that can lead to variations in the need for hospitalization beyond the provision of renal replacement therapy. METHODS: Patient-level cost data for incident renal replacement therapy patients in England were obtained as a result of linkage of the Hospital Episodes Statistics dataset to UK Renal Registry data. Regression models were developed to explore variations in hospital costs in relation to treatment modality, number of years on treatment and factors such as age and comorbidities. The final models were then used to predict annual costs for patients with different sets of characteristics. RESULTS: Excluding the cost of renal replacement therapy itself, inpatient costs generally decreased with number of years on treatment for haemodialysis and transplant patients, whereas costs for patients receiving peritoneal dialysis remained constant. Diabetes was associated with higher mean annual costs for all patients irrespective of treatment modality and hospital setting. Age did not have a consistent effect on costs. CONCLUSIONS: Combining predicted hospital costs with the fixed costs of renal replacement therapy showed that the total cost differential for a patient continuing on dialysis rather than receiving a transplant is considerable following the first year of renal replacement therapy, thus reinforcing the longer-term economic advantage of transplantation over dialysis for the health service.

The mortality and hospitalization rates associated with the long interdialytic gap in thrice-weekly hemodialysis patients.

Excess mortality and hospitalization have been identified after the 2-day gap in thrice-weekly hemodialysis patients compared with 1-day intervals, although findings vary internationally. Here we aimed to identify factors associated with mortality and hospitalization events in England using an incident cohort of 5864 hemodialysis patients from years 2002 to 2006 inclusive in the UK Renal Registry linked to hospitalization data. Higher admission rates were seen after the 2-day gap irrespective of whether thrice-weekly dialysis sequence commenced on a Monday or Tuesday (2.4 per year after the 2-day gap vs. 1.4 for the rest of the week, rate ratio 1.7). The greatest differences in admission rates were seen in patients admitted with fluid overload or with conditions associated with a high risk of fluid overload. Increased mortality following the 2-day gap was similarly independent of session pattern (20.5 vs. 16.7 per 100 patient years, rate ratio 1.22), with these increases being driven by out-of-hospital death (rate ratio 1.59 vs. 1.06 for in-hospital death). Non-white patients had an overall survival advantage, with the increased mortality after the 2-day gap being found only in whites. Thus, fluid overload may increase the risk of hospital admission after the 2-day gap and that the increased out-of-hospital mortality may relate to a higher incidence of sudden death. Future work should focus on exploring interventions in these subgroups.

Patient attitudes towards kidney transplant listing: qualitative findings from the ATTOM study.

BACKGROUND: There is variation in time to listing and rates of listing for transplantation between renal units in the UK. While research has mainly focused on healthcare organization, little is known about patient perspectives of entry onto the transplant waiting list. This qualitative study aimed to explore patients' views and experiences of kidney transplant listing. METHODS: Semi-structured interviews were conducted with patients aged under 75, who were on dialysis and on the transplant waiting list, not on the waiting list, undergoing assessment for listing or who had received a transplant. Patients were recruited from a purposive sample of nine UK renal units, which included transplanting and non-transplanting units and units with high and low wait-listing patterns. Interviews were transcribed verbatim and analysed using thematic analysis. RESULTS: Fifty-three patients (5-7 per renal unit) were interviewed. Patients reported that they had received little information about the listing process. Some patients did not know if they were listed or had found they were not listed when they had thought they were on the list. Others expressed distress when they felt they had been excluded from potential listing based on age and/or comorbidity and felt the process was unfair. Many patients were not aware of pre-emptive transplantation and believed they had to be on dialysis before being able to be listed. There was some indication that pre-emptive transplantation was discussed more often in transplant than non-transplant units. Lastly, some patients were reluctant to consider family members as potential donors as they reported they would feel 'guilty' if the donor suffered subsequent negative effects. CONCLUSIONS: Findings suggest a need to review current practice to further understand individual and organizational reasons for the renal unit variation identified in patient understanding of transplant listing. The communication of information warrants attention to ensure patients are fully informed about the listing process and opportunity for pre-emptive transplantation in a way that is meaningful and understandable to them.

Analysis of data from the ERA-EDTA Registry indicates that conventional treatments for chronic kidney disease do not reduce the need for renal replacement therapy in autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) is a major cause of end-stage kidney failure, but is often identified early and therefore amenable to timely treatment. Interventions known to postpone the need for renal replacement therapy (RRT) in non-ADPKD patients have also been tested in ADPKD patients, but with inconclusive results. To help resolve this we determined changes in RRT incidence rates as an indicator for increasing effective renoprotection over time in ADPKD. We analyzed data from the European Renal Association-European Dialyses and Transplant Association Registry on 315,444 patients starting RRT in 12 European countries between 1991 and 2010, grouped into four 5-year periods. Of them, 20,596 were due to ADPKD. Between the first and last period the mean age at onset of RRT increased from 56.6 to 58.0 years. The age- and gender-adjusted incidence rate of RRT for ADPKD increased slightly over the four periods from 7.6 to 8.3 per million population. No change over time was found in the incidence of RRT for ADPKD up to age 50, whereas in recent time periods the incidence in patients above the age of 70 clearly increased. Among countries there was a significant positive association between RRT take-on rates for non-ADPKD kidney disease and ADPKD. Thus, the increased age at onset of RRT is most likely due to an increased access for elderly ADPKD patients or lower competing risk prior to the start of RRT rather than the consequence of effective emerging renoprotective treatments for ADPKD.

The body composition and excretory burden of lean, obese, and severely obese individuals has implications for the assessment of chronic kidney disease.

Obesity could affect associations between creatinine generation, estimated body surface area, and excretory burden, with effects on chronic kidney disease assessment. We therefore examined the impact of obesity on the performances of estimated glomerular filtration rate (eGFR), the urine albumin:creatinine ratio (ACR), and excretory burden in 3611 participants of the Chronic Renal Insufficiency Cohort. Urine creatinine excretion significantly increased with body mass index (BMI) (34 and 31% greater at 40 kg/m(2) or more versus the normal of 18.5-25 kg/m(2)) in men and women, respectively, such that patients with a normal BMI and an ACR of 30 mg/g had the same 24-h albuminuria as severely obese patients with ACR 23 mg/g. The bias of eGFR (referenced to body surface area-indexed iothalamate (i-)GFR) had a U-shaped relationship to obesity in men but progressively increased in women. Nevertheless, obesity-associated body surface area increases were accompanied by a greater absolute (non-indexed) iGFR for a given eGFR, particularly in men. Two men with eGFRs of 45 ml/min per 1.73 m(2), height 1.76 m, and BMI 22 or 45 kg/m(2) had absolute iGFRs of 46 and 62 ml/min, respectively. The excretory burden, assessed as urine urea nitrogen and estimated dietary phosphorus, sodium, and potassium intakes, also increased in obesity. However, obese men had lower odds of anemia, hyperkalemia, and hyperphosphatemia. Thus, for a given ACR and eGFR, obese individuals have greater albuminuria, absolute GFR, and excretory burden. This has implications for chronic kidney disease management, screening, and research.

Do patients with chronic kidney disease get optimal cardiovascular risk reduction?

PURPOSE OF REVIEW: Cardiovascular events are the major cause of death in chronic kidney disease (CKD). Individuals with CKD have a substantially greater risk of cardiovascular disease compared with the general population but have largely been excluded from clinical trials. This review highlights the complex pathogenesis of cardiovascular disease, discusses the evidence for cardiovascular risk reduction and assesses the achievement of cardiovascular treatment targets in CKD. RECENT FINDINGS: There is evidence to support both blood pressure and cholesterol reduction in the CKD population. The risk of bleeding with antiplatelet drugs is high in CKD and these should be used with caution. Although there has been recent interest in targeting nonclassical cardiovascular risk factors in CKD, few trials have demonstrated any significant reduction in cardiovascular risk. Smoking cessation remains important but is poorly studied in CKD with many dialysis patients still smoking. SUMMARY: The pathogenesis of cardiovascular disease in CKD differs subtly from that of non-CKD patients. As renal function declines, the role and impact of treating classical risk factors may change and diminish. However, hypertension, hypercholesterolaemia and smoking cessation management should be optimized and may require multiple agents and approaches, particularly as CKD advances. Treatment of hypertension would appear to be one management area in which performance is less than ideal. Future work should focus on new management strategies and drug combinations that tackle the classical risk factors as well as better designed longitudinal and randomized control trials of nonclassical risk factors. Patients with CKD should be included in all cardiovascular intervention studies, given their poor outcomes without interventions.

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.

Estimated albumin excretion rate versus urine albumin-creatinine ratio for the estimation of measured albumin excretion rate: derivation and validation of an estimated albumin excretion rate equation.

BACKGROUND: Glomerular filtration rate estimation equations use demographic variables to account for predicted differences in creatinine generation rate. In contrast, assessment of albuminuria from urine albumin-creatinine ratio (ACR) does not account for these demographic variables, potentially distorting albuminuria prevalence estimates and clinical decision making. STUDY DESIGN: Polynomial regression was used to derive an age-, sex-, and race-based equation for estimation of urine creatinine excretion rate, suitable for use in automated estimated albumin excretion rate (eAER) reporting. SETTING & PARTICIPANTS: The MDRD (Modification of Diet in Renal Disease) Study cohort (N=1,693) was used for equation derivation. Validation populations were the CRIC (Chronic Renal Insufficiency Cohort; N=3,645) and the DCCT (Diabetes Control and Complications Trial; N=1,179). INDEX TEST: eAER, calculated by multiplying ACR by estimated creatinine excretion rate, and ACR. REFERENCE TEST: Measured albumin excretion rate (mAER) from timed 24-hour urine collection. RESULTS: eAER estimated mAER more accurately than ACR; the percentages of CRIC participants with eAER within 15% and 30% of mAER were 33% and 60%, respectively, versus 24% and 39% for ACR. Equivalent proportions in DCCT were 52% and 86% versus 15% and 38%. The median bias of ACR was -20.1% and -37.5% in CRIC and DCCT, respectively, whereas that of eAER was +3.8% and -9.7%. Performance of eAER also was more consistent across age and sex categories than ACR. LIMITATIONS: Single timed urine specimens used for mAER, ACR, and eAER. CONCLUSIONS: Automated eAER reporting potentially is a useful approach to improve the accuracy and consistency of clinical albuminuria assessment.

Association between pre-transplant dialysis modality and patient and graft survival after kidney transplantation.

BACKGROUND: Previous studies have found inconsistent associations between pre-transplant dialysis modality and subsequent post-transplant survival. We aimed to examine this relationship using the instrumental variable method and to compare the results with standard Cox regression. METHODS: We included 29 088 patients (age >20 years) from 16 European national or regional renal registries who received a first kidney transplant between 1 January 1999 and 31 December 2008 and were on dialysis before transplantation for a period between 90 days and 10 years. Standard multivariable Cox regression examined the association of individually assigned pre-transplant dialysis modality with post-transplant patient and graft survival. To decrease confounding-by-indication through unmeasured factors, we applied the instrumental variable method that used the case-mix adjusted centre percentage of peritoneal dialysis (PD) as predictor variable. RESULTS: Standard analyses adjusted for age, sex, primary renal disease, donor type, duration of dialysis, year of transplantation and country suggested that PD before transplantation was associated with better patient [hazard ratio, HR (95% CI) = 0.83 (0.76-0.91)] and graft survival (HR (95% CI) 0.90 (0.84-0.96)) when compared with haemodialysis (HD). In contrast, the instrumental variable analysis showed that a 10% increase in the case-mix adjusted centre percentage of patients on PD was neither associated with post-transplant patient survival [HR (95% CI = 1.00 (0.97-1.04)] nor with graft survival [HR (95% CI) = 1.01 (0.98-1.04)]. CONCLUSIONS: The instrumental variable method failed to confirm the associations found in standard Cox regression between pre-transplant dialysis modality and patient and graft survival after transplantation. The lack of association in instrumental variable analysis may be due to better control of residual confounding.

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.

Patterns of hospitalisation before and following initiation of haemodialysis: a 5 year single centre study.

BACKGROUND The utilisation of healthcare resources by prevalent haemodialysis patients has been robustly evaluated with regard to the provision of outpatient haemodialysis; however, the impact of hospitalisation among such patients is poorly defined. Minimal information is available in the UK to estimate the health and economic burden associated with the inpatient management of prevalent haemodialysis patients. The aim of this study was to assess the pattern of hospitalisation among a cohort of haemodialysis patients, before and following their initiation of haemodialysis. In addition the study sought to assess the impact of their admissions on bed occupancy in a large tertiary referral hospital in a single region in the UK. METHODS All admission episodes were reviewed and those receiving dialysis with the Belfast City Hospital Programme were identified over a 5 year period from January 2001 to December 2005. This tertiary referral centre provides dialysis services for a population of approximately 700 000 and additional specialist renal services for the remainder of Northern Ireland. The frequency and duration of hospitalisation, and contribution to bed day occupancy of haemodialysis patients, was determined and compared to other common conditions which are known to be associated with high bed occupancy. In addition, the pattern and timing of admissions in dialysis patients in relation to their dialysis initiation date was assessed. RESULTS Over the 5 year study period, 798 haemodialysis patients were admitted a total of 2882 times. These accounted for 2.5% of all admissions episodes; the median number of admissions for these patients was 3 (2-5) which compared with 1 (1-2) for non-dialysis patients. The majority of first hospitalisations (54%) were within 100 days before or after commencement of maintenance dialysis therapy. In all clinical specialties the median length of stay for haemodialysis patients was significantly longer than for patients not on haemodialysis (p=0.004). In multivariate analysis with adjustment for age, gender, and other clinically relevant diagnostic codes, maintenance haemodialysis patients stayed on average 3.75 times longer than other patient groups (ratio of geometric means 3.75, IQR 3.46-4.06). CONCLUSIONS Maintenance haemodialysis therapy is an important risk factor for prolonged hospitalisation regardless of the primary reason for admission. Such patients require admission more frequently than the general hospital population, particularly within 100 days before and after initiation of their first dialysis treatment.

The finding of reduced estimated glomerular filtration rate is associated with increased mortality in a large UK population.

BACKGROUND: CKD as defined by KDIGO/KDOQI has been shown to affect ~ 8.5% of the UK population. The prevalence of CKD in the UK is similar to that in the USA, yet incident dialysis rates are dramatically different. This retrospective cohort study investigates the association between reduced kidney function and mortality in a large UK population. METHODS: All serum creatinine results covering Northern Ireland's 1.7 million population were collected between 1 January 2001 and 31 December 2002. Estimated glomerular filtration rates (eGFR) were calculated for all serum creatinine measurements using four-variable MDRD equation (IDMS aligned). Patients were followed up for both all-cause and cardiovascular mortality data until the end of December 2006. Patients on renal replacement therapy were excluded. Subgroup analysis in the 75,345 subjects enrolled within a parallel primary care study permitted additional survival analysis with adjustment for traditional cardiovascular risk factors. RESULTS: A total of 1,967,827 serum creatinine results from 533,798 patients were collected. During the period of follow-up, 59,980 deaths occurred. In multivariate survival analysis, using eGFR as a time-varying covariate, a graded association between CKD (defined by eGFR) and all-cause mortality was identified. Compared with participants with an eGFR of > 60 mL/min/1.73 m(2), the adjusted hazard ratios (and 95% confidence intervals) for participants with an eGFR of 45-59 mL/min/1.73 m(2) was 1.02 (0.99-1.04), an eGFR of 30-44 mL/min/1.73 m(2) was 1.44 (1.40-1.47), an eGFR of 15-29 mL/min/1.73 m(2) was 2.12 (2.05-2.20) and an eGFR of < 15 mL/min/1.73 m(2) was 3.46 (3.24-3.70). Significantly, increased all-cause mortality was associated with an eGFR < 45 mL/min/1.73 m(2) following adjustment for age and gender. The association between cardiovascular mortality and reduced renal function continued to be significant for participants with an eGFR of 45-65 mL/min/1.73 m(2). Subgroup analysis in 75,345 individuals with more detailed clinical information available confirmed this association following adjustment for traditional cardiovascular risk factors in addition to age and gender. CONCLUSIONS: This study demonstrates a graded association between reduced renal function as represented by eGFR and mortality in a UK population. The all-cause and cardiovascular mortality risk increases sharply when estimated GFR falls < 45 mL/min/1.73 m(2). The association between an eGFR measured between 45 and 65 mL/min/1.73 m(2) and cardiovascular mortality persists in this cohort and highlights the ongoing uncertainty in accurately categorizing renal dysfunction.

UK Renal Registry 12th Annual Report (December 2009): chapter 13: the UK Renal Registry advanced CKD study: frequency of incorrect reporting of date of start of RRT.

BACKGROUND: A preliminary review of the UK Renal Registry (UKRR) pre-RRT study data revealed results suggesting that, for some patients, the date of start of renal replacement therapy (RRT), as reported to the UKRR, was incorrect and often significantly later than the true date of start. A more detailed study then aimed to validate a set of criteria to identify patients with an incorrect start date. METHODS: Pre-RRT laboratory data were electronically extracted from 8,810 incident RRT patients from 9 UK renal centres. Any patient with a low urea (<15 mmol/L) at the start of RRT or with a substantial improvement in kidney function (either a fall in urea >10 mmol/L or rise in eGFR >2 ml/ min/1.73 m) within the two months prior to RRT were considered to potentially have an incorrect date of start. In 4 selected centres, the electronic patient records of all patients flagged were reviewed to validate these criteria. RESULTS: Of 8,810 patients, 1,616 (18.3%) were flagged by the identification criteria as having a potentially incorrect date of start of RRT, although a single centre accounted for 41% of the total flagged cohort. Of these flagged patients, 61.7% had been assigned an incorrect date of start of haemodialysis (HD), 5.7% had evidence of acute RRT being given before the reported date of start of HD and 9.2% had evidence of starting peritoneal dialysis exchanges prior to the reported date of start. Of those flagged, 10.7% had a correct date of start of RRT. CONCLUSIONS: Accurate reporting of RRT episodes is vital for the analysis of time dependent studies such as survival or time to transplantation. A proportion of patients starting RRT were assigned an incorrect start date. In order to improve the accuracy of this reporting the UK Renal Registry must work with renal centres and clinical staff on improving data input for the start of RRT.

The impact of admissions for the management of end-stage renal disease on hospital bed occupancy.

BACKGROUND: End-stage renal disease (ESRD) is increasingly prevalent but the inpatient costs associated with this condition are poorly defined due to limitations with data extraction and failure to differentiate between hospitalisation for renal and non-renal disease reasons. The impact of admissions primarily for the management of ESRD on hospital bed utilisation was assessed over a 5-year period in a large teaching hospital. METHODS: All admission episodes were reviewed and the ESRD group was identified by a primary International Classification of Diseases code for ESRD or a non-specific primary renal failure code with a secondary code for ESRD. The frequency and duration of hospitalisation and contribution to bed day occupancy of this group with ESRD was determined. RESULTS: There were 70,808 patients responsible for a total of 116,915 admissions and 919,212 bed days over the study period. Of these, 988 (1.4%) patients were admitted for the management of ESRD, accounting for 2,387 (2.0%) of admissions and utilisation of 23,011 (2.5%) bed days. After adjustment for age and gender, those admitted for ESRD management were significantly more likely to have a prolonged admission exceeding 30 days (odds ratio 1.46, 95% confidence interval 1.23-1.72, p < 0.001). When the admission was an emergency rather than an elective event, the patient was 4.6 times more likely to be hospitalised for over 30 days. CONCLUSIONS: Persons admitted for ESRD management are hospitalised more frequently and for longer than the overall inpatient population, occupying a substantial number of bed days.