Pancreatic insufficiency as a complication of type 1 diabetes causing enteric hyperoxaluria in a transplant kidney.

A kidney transplant recipient with a medical history of type 1 diabetes mellitus (T1DM) presents to the clinic with an acute kidney injury (AKI) and diarrhoea. Kidney biopsy found deposition of focal oxalate crystals, and further investigation revealed a raised 24-hour urinary oxalate and reduced faecal elastase. Therefore, we present a case of acute oxalate nephropathy (AON) secondary to enteric hyperoxaluria as a result of pancreatic insufficiency caused by T1DM. T1DM is a common cause of end-stage renal failure and exocrine pancreatic insufficiency. Therefore, AON secondary to enteric hyperoxaluria should be considered in patients with a transplant AKI. Earlier testing of 24-hour urinary oxalate and faecal elastase could generate diagnosis before biopsy results and allow commencement of pancreatic replacement therapy earlier to avoid permanent loss of kidney function.

Nocturia and Chronic Kidney Disease: Systematic Review and Nominal Group Technique Consensus on Primary Care Assessment and Treatment.

CONTEXT: Reduced renal function impairs salt and water homeostasis, which can drive nocturnal or 24-h polyuria. Nocturia can arise early in chronic kidney disease (CKD). Evidence-based recommendations can facilitate management outside nephrology clinics. OBJECTIVE: To conduct a systematic review (SR) of nocturia in CKD and achieve expert consensus for management in primary care and in specialist clinics outside nephrology. EVIDENCE ACQUISITION: Four databases were searched from January 2000 to April 2020. A total of 4011 titles and abstracts were screened, and 108 studies underwent full-text screening. Seven studies met the inclusion criteria and two were identified through other sources. Consensus was achieved among an expert panel with public involvement using the nominal group technique (NGT). EVIDENCE SYNTHESIS: Several plausible mechanisms contribute to nocturnal or 24-h polyuria in CKD, but there is little evidence on interventions to improve nocturia. NGT assessment recommendations for nocturia (at least two voids per night) in patients with CKD or at risk of CKD being assessed in a non-nephrology setting are: history (thirst, fluid intake), medication review (diuretics, lithium, calcium channel antagonists, nonsteroidal anti-inflammatory medications), examination (oedematous state, blood pressure), urinalysis (haematuria and albumin/creatinine ratio), blood tests (blood urea, serum creatinine and electrolytes, estimated glomerular filtration rate), and a bladder diary. Renal ultrasound should follow local CKD guidelines. Treatment options include optimising blood pressure control, dietary adjustment to reduce salt intake, fluid advice, and a medication review. Referral to specialist nephrology services should follow local guidelines. CONCLUSIONS: CKD should be considered when evaluating patients with nocturia. The aim of assessment is to identify mechanisms and instigate therapy, but the latter may be more applicable to reducing wider morbidity associated with CKD than nocturia itself. PATIENT SUMMARY: People with kidney disease can suffer severe sleep disturbance because of a need to pass urine overnight. We looked at published research and found some useful information about the underlying mechanisms. A group of experts was able to develop practical approaches for assessing and treating this condition.

Changes in quality of life (QoL) and other patient-reported outcome measures (PROMs) in living-donor and deceased-donor kidney transplant recipients and those awaiting transplantation in the UK ATTOM programme: a longitudinal cohort questionnaire survey with additional qualitative interviews.

OBJECTIVE: To examine quality of life (QoL) and other patient-reported outcome measures (PROMs) in kidney transplant recipients and those awaiting transplantation. DESIGN: Longitudinal cohort questionnaire surveys and qualitative semi-structured interviews using thematic analysis with a pragmatic approach. SETTING: Completion of generic and disease-specific PROMs at two time points, and telephone interviews with participants UK-wide. PARTICIPANTS: 101 incident deceased-donor (DD) and 94 incident living-donor (LD) kidney transplant recipients, together with 165 patients on the waiting list (WL) from 18 UK centres recruited to the Access to Transplantation and Transplant Outcome Measures (ATTOM) programme completed PROMs at recruitment (November 2011 to March 2013) and 1 year follow-up. Forty-one of the 165 patients on the WL received a DD transplant and 26 received a LD transplant during the study period, completing PROMs initially as patients on the WL, and again 1 year post-transplant. A subsample of 10 LD and 10 DD recipients participated in qualitative semi-structured interviews. RESULTS: LD recipients were younger, had more educational qualifications and more often received a transplant before dialysis. Controlling for these and other factors, cross-sectional analyses at 12 months post-transplant suggested better QoL, renal-dependent QoL and treatment satisfaction for LD than DD recipients. Patients on the WL reported worse outcomes compared with both transplant groups. However, longitudinal analyses (controlling for pre-transplant differences) showed that LD and DD recipients reported similarly improved health status and renal-dependent QoL (p<0.01) pre-transplant to post-transplant. Patients on the WL had worsened health status but no change in QoL. Qualitative analyses revealed transplant recipients' expectations influenced their recovery and satisfaction with transplant. CONCLUSIONS: While cross-sectional analyses suggested LD kidney transplantation leads to better QoL and treatment satisfaction, longitudinal assessment showed similar QoL improvements in PROMs for both transplant groups, with better outcomes than for those still wait-listed. Regardless of transplant type, clinicians need to be aware that managing expectations is important for facilitating patients' adjustment post-transplant.

Inequity in Access to Transplantation in the United Kingdom.

BACKGROUND AND OBJECTIVES: Despite the presence of a universal health care system, it is unclear if there is intercenter variation in access to kidney transplantation in the United Kingdom. This study aims to assess whether equity exists in access to kidney transplantation in the United Kingdom after adjustment for patient-specific factors and center practice patterns. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In this prospective, observational cohort study including all 71 United Kingdom kidney centers, incident RRT patients recruited between November 2011 and March 2013 as part of the Access to Transplantation and Transplant Outcome Measures study were analyzed to assess preemptive listing (n=2676) and listing within 2 years of starting dialysis (n=1970) by center. RESULTS: Seven hundred and six participants (26%) were listed preemptively, whereas 585 (30%) were listed within 2 years of commencing dialysis. The interquartile range across centers was 6%-33% for preemptive listing and 25%-40% for listing after starting dialysis. Patient factors, including increasing age, most comorbidities, body mass index >35 kg/m2, and lower socioeconomic status, were associated with a lower likelihood of being listed and accounted for 89% and 97% of measured intercenter variation for preemptive listing and listing within 2 years of starting dialysis, respectively. Asian (odds ratio, 0.49; 95% confidence interval, 0.33 to 0.72) and Black (odds ratio, 0.43; 95% confidence interval, 0.26 to 0.71) participants were both associated with reduced access to preemptive listing; however Asian participants were associated with a higher likelihood of being listed after starting dialysis (odds ratio, 1.42; 95% confidence interval, 1.12 to 1.79). As for center factors, being registered at a transplanting center (odds ratio, 3.1; 95% confidence interval, 2.36 to 4.07) and a universal approach to discussing transplantation (odds ratio, 1.4; 95% confidence interval, 1.08 to 1.78) were associated with higher preemptive listing, whereas using a written protocol was associated negatively with listing within 2 years of starting dialysis (odds ratio, 0.7; 95% confidence interval, 0.58 to 0.9). CONCLUSIONS: Patient case mix accounts for most of the intercenter variation seen in access to transplantation in the United Kingdom, with practice patterns also contributing some variation. Socioeconomic inequity exists despite having a universal health care system.

Equity-Efficiency Trade-offs Associated With Alternative Approaches to Deceased Donor Kidney Allocation: A Patient-level Simulation.

BACKGROUND: The number of patients waiting to receive a kidney transplant outstrips the supply of donor organs. We sought to quantify trade-offs associated with different approaches to deceased donor kidney allocation in terms of quality-adjusted life years (QALYs), costs, and access to transplantation. METHODS: An individual patient simulation model was developed to compare 5 different approaches to kidney allocation, including the 2006 UK National Kidney Allocation Scheme (NKAS) and a QALY maximization approach designed to maximize health gains from a limited supply of donor organs. We used various sources of patient-level data to develop multivariable regression models to predict survival, health state utilities, and costs. We simulated the allocation of kidneys from 2200 deceased donors to a waiting list of 5500 patients and produced estimates of total lifetime costs and QALYs for each allocation scheme. RESULTS: Among patients who received a transplant, the QALY maximization approach generated 48 045 QALYs and cost £681 million, while the 2006 NKAS generated 44 040 QALYs and cost £625 million. When also taking into consideration outcomes for patients who were not prioritized to receive a transplant, the 2006 NKAS produced higher total QALYs and costs and an incremental cost-effectiveness ratio of £110 741/QALY compared with the QALY maximization approach. CONCLUSIONS: Compared with the 2006 NKAS, a QALY maximization approach makes more efficient use of deceased donor kidneys but reduces access to transplantation for older patients and results in greater inequity in the distribution of health gains between patients who receive a transplant and patients who remain on the waiting list.

Recipient Comorbidity and Survival Outcomes After Kidney Transplantation: A UK-wide Prospective Cohort Study.

BACKGROUND: Comorbidity is increasingly common in kidney transplant recipients, yet the implications for transplant outcomes are not fully understood. We analyzed the relationship between recipient comorbidity and survival outcomes in a UK-wide prospective cohort study-Access to Transplantation and Transplant Outcome Measures (ATTOM). METHODS: A total of 2100 adult kidney transplant recipients were recruited from all 23 UK transplant centers between 2011 and 2013. Data on 15 comorbidities were collected at the time of transplantation. Multivariable Cox regression models were used to analyze the relationship between comorbidity and 2-year graft survival, patient survival, and transplant survival (earliest of graft failure or patient death) for deceased-donor kidney transplant (DDKT) recipients (n = 1288) and living-donor kidney transplant (LDKT) recipients (n = 812). RESULTS: For DDKT recipients, peripheral vascular disease (hazard ratio [HR] 3.04, 95% confidence interval [CI]: 1.37-6.74; P = 0.006) and obesity (HR 2.27, 95% CI: 1.27-4.06; P = 0.006) were independent risk factors for graft loss, while heart failure (HR 3.77, 95% CI: 1.79-7.95; P = 0.0005), cerebrovascular disease (HR 3.45, 95% CI: 1.72-6.92; P = 0.0005), and chronic liver disease (HR 4.36, 95% CI: 1.29-14.71; P = 0.018) were associated with an increased risk of mortality. For LDKT recipients, heart failure (HR 3.83, 95% CI: 1.15-12.81; P = 0.029) and diabetes (HR 2.23, 95% CI: 1.03-4.81; P = 0.042) were associated with poorer transplant survival. CONCLUSIONS: The key comorbidities that predict poorer 2-year survival outcomes after kidney transplantation have been identified in this large prospective cohort study. The findings will facilitate assessment of individual patient risks and evidence-based decision making.

Establishing a tele-clinic service for kidney transplant recipients through a patient-codesigned quality improvement project.

Kidney transplant patients in our regional centre travel long distances to attend routine hospital follow-up appointments. Patients incur travel costs and productivity losses as well as adverse environmental impacts. A significant proportion of these patients, who may not require physical examination, could potentially be managed through telephone consultations (tele-clinic). We adopted a Quality Improvement approach with iterative Plan-Do-Study-Act (PDSA) cycles to test the introduction of a tele-clinic service. We codesigned the service with patients and developed a prototype delivery model that we then tested over two PDSA improvement ramps containing multiple PDSA cycles to embed the model into routine service delivery. Nineteen tele-clinics were held involving 168 kidney transplant patients (202 tele-consultations). 2.9% of tele-clinic patients did not attend compared with 6.9% for face-to-face appointments. Improving both blood test quality and availability for the tele-clinic was a major focus of activity during the project. Blood test quality for tele-clinics improved from 25% to 90.9%. 97.9% of survey respondents were satisfied overall with their tele-clinic, and 96.9% of the patients would recommend this to other patients. The tele-clinic saved 3527 miles of motorised travel in total. This equates to a saving of 1035 kgCO2. There were no unplanned admissions within 30 days of the tele-clinic appointment. The service provided an immediate saving of £6060 for commissioners due to reduced tele-clinic tariff negotiated locally (£30 less than face-to-face tariff). The project has shown that tele-clinics for kidney transplant patients are deliverable and well received by patients with a positive environmental impact and modest financial savings. It has the potential to be rolled out to other renal centres if a national tele-clinic tariff can be negotiated, and an integrated, appropriately reimbursed community phlebotomy system can be developed to facilitate remote monitoring of patients.

Limited health literacy is associated with reduced access to kidney transplantation.

Limited health literacy is common in patients with chronic kidney disease (CKD) and has been variably associated with adverse clinical outcomes. The prevalence of limited health literacy is lower in kidney transplant recipients than in individuals starting dialysis, suggesting selection of patients with higher health literacy for transplantation. We investigated the relationship between limited health literacy and clinical outcomes, including access to kidney transplantation, in a prospective UK cohort study of 2,274 incident dialysis patients aged 18-75 years. Limited health literacy was defined by a validated Single Item Literacy Screener (SILS). Multivariable regression was used to test for association with outcomes after adjusting for age, sex, socioeconomic status (educational level and car ownership), ethnicity, first language, primary renal diagnosis, and comorbidity. In fully adjusted analyses, limited health literacy was not associated with mortality, late presentation to nephrology, dialysis modality, haemodialysis vascular access, or pre-emptive kidney transplant listing, but was associated with reduced likelihood of listing for a deceased-donor transplant (hazard ratio [HR] 0.68; 95% confidence interval [CI] 0.51-0.90), receiving a living-donor transplant (HR 0.41; 95% CI 0.19-0.88), or receiving a transplant from any donor type (HR 0.65; 95% CI 0.44-0.96). Limited health literacy is associated with reduced access to kidney transplantation, independent of patient demographics, socioeconomic status, and comorbidity. Interventions to ameliorate the effects of low health literacy may improve access to kidney transplantation.

Automated high-throughput light-sheet fluorescence microscopy of larval zebrafish.

Light sheet fluorescence microscopy enables fast, minimally phototoxic, three-dimensional imaging of live specimens, but is currently limited by low throughput and tedious sample preparation. Here, we describe an automated high-throughput light sheet fluorescence microscope in which specimens are positioned by and imaged within a fluidic system integrated with the sheet excitation and detection optics. We demonstrate the ability of the instrument to rapidly examine live specimens with minimal manual intervention by imaging fluorescent neutrophils over a nearly 0.3 mm3 volume in dozens of larval zebrafish. In addition to revealing considerable inter-individual variability in neutrophil number, known previously from labor-intensive methods, three-dimensional imaging allows assessment of the correlation between the bulk measure of total cellular fluorescence and the spatially resolved measure of actual neutrophil number per animal. We suggest that our simple experimental design should considerably expand the scope and impact of light sheet imaging in the life sciences.

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.

Variation in Practice Patterns for Listing Patients for Renal Transplantation in the United Kingdom: A National Survey.

BACKGROUND: Despite the availability of guidelines for the evaluation of candidates for renal transplantation, variation in access to transplantation exists. This national survey investigates whether center variation exists in the assessment of patients for renal transplantation in the United Kingdom. METHODS: An online survey, informed by qualitative interviews, was distributed to all UK renal centers. This survey examined center approaches to chronic kidney disease service provision, transplant recipient assessment, education provision, and waitlisting decision making processes. Center reevaluation policies for patients already listed and priorities for future development were also examined. RESULTS: All 71 renal centers responded. Of these, 83% reviewed predialysis patients in a low clearance clinic. In 26% of the centers, transplantation was not discussed as a treatment option with all patients. Fourteen centers reported having a dedicated transplant assessment clinic, whereas 28% did not have a formal assessment protocol. Age was an exclusion criterion for listing in 3 centers, all of which had a cutoff at 75 years. Eighty-three percent of the centers excluded patients with a high body mass index. Cardiac investigations were risk-stratified in 90% of centers. Surgical involvement varied with 11% of centers listing patients without formal surgical review. There was no formal protocol in place to reevaluate listed patients in 62% of centers. CONCLUSIONS: There is wide variation in UK practice patterns for listing patients for renal transplantation, though its impact on access to transplantation is unclear. The extent to which center-specific and patient-specific factors affect access to transplantation requires further analysis in a prospective cohort of patients.

Estimating Health-State Utility Values in Kidney Transplant Recipients and Waiting-List Patients Using the EQ-5D-5L.

OBJECTIVES: To report health-state utility values measured using the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) in a large sample of patients with end-stage renal disease and to explore how these values vary in relation to patient characteristics and treatment factors. METHODS: As part of the prospective observational study entitled "Access to Transplantation and Transplant Outcome Measures," we captured information on patient characteristics and treatment factors in a cohort of incident kidney transplant recipients and a cohort of prevalent patients on the transplant waiting list in the United Kingdom. We assessed patients' health status using the EQ-5D-5L and conducted multivariable regression analyses of index scores. RESULTS: EQ-5D-5L responses were available for 512 transplant recipients and 1704 waiting-list patients. Mean index scores were higher in transplant recipients at 6 months after transplant surgery (0.83) compared with patients on the waiting list (0.77). In combined regression analyses, a primary renal diagnosis of diabetes was associated with the largest decrement in utility scores. When separate regression models were fitted to each cohort, female gender and Asian ethnicity were associated with lower utility scores among waiting-list patients but not among transplant recipients. Among waiting-list patients, longer time spent on dialysis was also associated with poorer utility scores. When comorbidities were included, the presence of mental illness resulted in a utility decrement of 0.12 in both cohorts. CONCLUSIONS: This study provides new insights into variations in health-state utility values from a single source that can be used to inform cost-effectiveness evaluations in patients with end-stage renal disease.

Predicting patient survival after deceased donor kidney transplantation using flexible parametric modelling.

BACKGROUND: The influence of donor and recipient factors on outcomes following kidney transplantation is commonly analysed using Cox regression models, but this approach is not useful for predicting long-term survival beyond observed data. We demonstrate the application of a flexible parametric approach to fit a model that can be extrapolated for the purpose of predicting mean patient survival. The primary motivation for this analysis is to develop a predictive model to estimate post-transplant survival based on individual patient characteristics to inform the design of alternative approaches to allocating deceased donor kidneys to those on the transplant waiting list in the United Kingdom. METHODS: We analysed data from over 12,000 recipients of deceased donor kidney or combined kidney and pancreas transplants between 2003 and 2012. We fitted a flexible parametric model incorporating restricted cubic splines to characterise the baseline hazard function and explored a range of covariates including recipient, donor and transplant-related factors. RESULTS: Multivariable analysis showed the risk of death increased with recipient and donor age, diabetic nephropathy as the recipient's primary renal diagnosis and donor hypertension. The risk of death was lower in female recipients, patients with polycystic kidney disease and recipients of pre-emptive transplants. The final model was used to extrapolate survival curves in order to calculate mean survival times for patients with specific characteristics. CONCLUSION: The use of flexible parametric modelling techniques allowed us to address some of the limitations of both the Cox regression approach and of standard parametric models when the goal is to predict long-term survival.

Access to Transplantation and Transplant Outcome Measures (ATTOM): study protocol of a UK wide, in-depth, prospective cohort analysis.

INTRODUCTION: There is significant intercentre variability in access to renal transplantation in the UK due to poorly understood factors. The overarching aims of this study are to improve equity of access to kidney and kidney-pancreas transplantation across the UK and to optimise organ allocation to maximise the benefit and cost-effectiveness of transplantation. METHODS AND ANALYSIS: 6844 patients aged 18-75 years starting dialysis and/or receiving a transplant together with matched patients active on the transplant list from all 72 UK renal units were recruited between November 2011 and March 2013 and will be followed for at least 3 years. The outcomes of interest include patient survival, access to the transplant list, receipt of a transplant, patient-reported outcome measures (PROMs) including quality of life, treatment satisfaction, well-being and health status on different forms of renal replacement therapy. Sociodemographic and clinical data were prospectively collected from case notes and from interviews with patients and local clinical teams. Qualitative process exploration with clinical staff will help identify unit-specific factors that influence access to renal transplantation. A health economic analysis will explore costs and outcomes associated with alternative approaches to organ allocation. The study will deliver: (1) an understanding of patient and unit-specific factors influencing access to renal transplantation in the UK, informing potential changes to practices and policies to optimise outcomes and reduce intercentre variability; (2) a patient-survival probability model to standardise access to the renal transplant list and (3) an understanding of PROMs and health economic impact of kidney and kidney-pancreas transplantation to inform the development of a more sophisticated and fairer organ allocation algorithm. ETHICS AND DISSEMINATION: The protocol has been independently peer reviewed by National Institute for Health Research (NIHR) and approved by the East of England Research Ethics Committee. The results will be published in peer-reviewed journals and presented at conferences.

The DESCARTES-Nantes survey of kidney transplant recipients displaying clinical operational tolerance identifies 35 new tolerant patients and 34 almost tolerant patients.

BACKGROUND: Kidney recipients maintaining a prolonged allograft survival in the absence of immunosuppressive drugs and without evidence of rejection are supposed to be exceptional. The ERA-EDTA-DESCARTES working group together with Nantes University launched a European-wide survey to identify new patients, describe them and estimate their frequency for the first time. METHODS: Seventeen coordinators distributed a questionnaire in 256 transplant centres and 28 countries in order to report as many 'operationally tolerant' patients (TOL; defined as having a serum creatinine <1.7 mg/dL and proteinuria <1 g/day or g/g creatinine despite at least 1 year without any immunosuppressive drug) and 'almost tolerant' patients (minimally immunosuppressed patients (MIS) receiving low-dose steroids) as possible. We reported their number and the total number of kidney transplants performed at each centre to calculate their frequency. RESULTS: One hundred and forty-seven questionnaires were returned and we identified 66 TOL (61 with complete data) and 34 MIS patients. Of the 61 TOL patients, 26 were previously described by the Nantes group and 35 new patients are presented here. Most of them were noncompliant patients. At data collection, 31/35 patients were alive and 22/31 still operationally tolerant. For the remaining 9/31, 2 were restarted on immunosuppressive drugs and 7 had rising creatinine of whom 3 resumed dialysis. Considering all patients, 10-year death-censored graft survival post-immunosuppression weaning reached 85% in TOL patients and 100% in MIS patients. With 218 913 kidney recipients surveyed, cumulative incidences of operational tolerance and almost tolerance were estimated at 3 and 1.5 per 10 000 kidney recipients, respectively. CONCLUSIONS: In kidney transplantation, operational tolerance and almost tolerance are infrequent findings associated with excellent long-term death-censored graft survival.

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.

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.

Range-based control of dual-stage nanopositioning systems.

A novel dual-stage nanopositioner control framework is presented that considers range constraints. Dual-stage nanopositioners are becoming increasingly popular in applications such as scanning probe microscopy due to their unique ability to achieve long-range and high-speed operation. The proposed control approach addresses the issue that some precision positioning trajectories are not achievable through existing control schemes. Specifically, short-range, low-speed inputs are typically diverted to the long-range actuator, which coincidentally has lower positioning resolution. This approach then limits the dual-stage nanopositioner's ability to achieve the required positioning resolution that is needed in applications where range and frequency are not inversely correlated (which is a typical, but not always the correct assumption for dual stage systems). The proposed range-based control approach is proposed to overcome the limitations of existing control methods. Experimental results show that the proposed control strategy is effective.

Acoustic quasi-holographic images of scattering by vertical cylinders from one-dimensional bistatic scans.

When synthetic aperture sonar (SAS) is used to image elastic targets in water, subtle features can be present in the images associated with the dynamical response of the target being viewed. In an effort to improve the understanding of such responses, as well as to explore alternative image processing methods, a laboratory-based system was developed in which targets were illuminated by a transient acoustic source, and bistatic responses were recorded by scanning a hydrophone along a rail system. Images were constructed using a relatively conventional bistatic SAS algorithm and were compared with images based on supersonic holography. The holographic method is a simplification of one previously used to view the time evolution of a target's response [Hefner and Marston, ARLO 2, 55-60 (2001)]. In the holographic method, the space-time evolution of the scattering was used to construct a two-dimensional image with cross range and time as coordinates. Various features for vertically hung cylindrical targets were interpreted using high frequency ray theory. This includes contributions from guided surface elastic waves, as well as transmitted-wave features and specular reflection.

Chronic kidney disease in kidney transplant recipients-is it different from chronic native kidney disease?

BACKGROUND: The rate of change in estimated glomerular filtration rate (ΔeGFR), factors influencing ΔeGFR, and its association with mortality has not been well studied in renal transplant recipients. METHODS.: Adult kidney-only recipients between January 2001 and December 2004, with surviving grafts 1 year after transplantation, from England and Wales were followed up till 31 December 2006, graft failure or death. The four variable modification of diet in renal disease equation was used to estimate GFR and ΔeGFR assessed using linear least square regression. ΔeGFR of -1 mL/min/1.73m per year and above was considered to be stable or improving function. Linear regression and Cox regression analyses were used to examine factors influencing ΔeGFR and its association with mortality, respectively. RESULTS: Of the 2, 927 patients included, ΔeGFR was -1.3±6.0 mL/min/1.73 m per year and eGFR remained stable or improved in the majority (54.8%). Baseline graft function at 1 year or live donor status did not influence ΔeGFR. Male donor to female recipient transplantation, younger recipients, diabetes, white race, and human leukocyte antigen mismatch were associated with faster decline in eGFR. ΔeGFR was not associated with mortality when censored for graft failure. CONCLUSIONS: Majority of renal transplant recipients experienced stable or improved graft function. Specific donor and recipient characteristics influenced the rate of decline in eGFR. The lack of association of ΔeGFR with mortality, the stability of eGFR in the majority, and influence of donor characteristics on ΔeGFR suggest caution when applying prognosis knowledge from the native kidney disease to the kidney transplant population.