Publications by authors named "Christopher Dudley"

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.

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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.

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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.

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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 (=2676) and listing within 2 years of starting dialysis (=1970) by center.

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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.

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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.

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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).

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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Article Synopsis
  • Living donor kidney transplants generally result in better outcomes than deceased donor transplants, but results can vary significantly based on several factors.
  • An analysis of over 3,000 cases revealed that while patient survival is higher for related donors, graft survival is better for unrelated donors, although these differences diminished once other influencing factors were considered.
  • Key findings indicate that older donor age negatively impacts patient survival and that factors like recipient diabetes and gender also play a role, but the expected impact of HLA mismatches was not observed.
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Background: Registry data can be used to examine whether there are differences between individual renal units in the proportion of dialysis patients listed for renal transplantation, to investigate possible reasons for any differences observed, and to discover whether highlighting these anomalies can influence practice.

Methods: A cross-sectional study of 12, 401 prevalent adult dialysis patients from 41 renal units across England and Wales was performed. The proportion of patients registered on the deceased donor transplant waiting list was determined for each renal unit.

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Article Synopsis
  • The study investigates the impact of repeated HLA mismatches on kidney transplant outcomes in patients who previously received cardiothoracic transplants in the UK.
  • It found that 30% of patients had a repeat HLA mismatch, but demographics and immunosuppressive treatment were similar across groups.
  • Importantly, the research concluded that repeat mismatches did not negatively affect kidney function or survival rates at 1 and 5 years post-transplant.
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Article Synopsis
  • Kidney transplant patients are at risk of quick bone density loss and fractures.
  • A study involved 93 patients split into treatment (pamidronate) and control groups, assessing changes in bone mineral density over 24 months.
  • Results showed pamidronate significantly preserved lumbar and hip bone density compared to controls, with lower annual fracture rates in the treatment group.
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