Background. Living donor kidney transplantation (LDKT) provides more timely access to transplantation and better clinical outcomes than deceased donor kidney transplantation (DDKT). This study investigated disparities in the utilization of LDKT in the UK. Methods. A total of 2055 adults undergoing kidney transplantation between November 2011 and March 2013 were prospectively recruited from all 23 UK transplant centres as part of the Access to Transplantation and Transplant Outcome Measures (ATTOM) study. Recipient variables independently associated with receipt of LDKT versus DDKT were identified. Results. Of the 2055 patients, 807 (39.3%) received LDKT and 1248 (60.7%) received DDKT. Multivariable modelling demonstrated a significant reduction in the likelihood of LDKT for older age {odds ratio [OR] 0.11 [95% confidence interval (CI) 0.08–0.17], P < 0.0001 for 65–75 years versus 18–34 years}; Asian ethnicity [OR 0.55 (95% CI 0.39–0.77), P = 0.0006 versus White]; Black ethnicity [OR 0.64 (95% CI 0.42–0.99), P = 0.047 versus White]; divorced, separated or widowed [OR 0.63 (95% CI 0.46–0.88), P = 0.030 versus married]; no qualifications [OR 0.55 (95% CI 0.42–0.74), P < 0.0001 versus higher education qualifications]; no car ownership [OR 0.51 (95% CI 0.37–0.72), P = 0.0001] and no home ownership [OR 0.65 (95% CI 0.85–0.79), P = 0.002]. The odds of LDKT varied significantly between countries in the UK. Conclusions. Among patients undergoing kidney transplantation in the UK, there are significant age, ethnic, socio-economic and geographic disparities in the utilization of LDKT. Further work is needed to explore the potential for targeted interventions to improve equity in living donor transplantation.

Worldwide, the number of patients able to benefit from kidney transplantation is greatly restricted by the severe shortage of deceased donor organs. Allocation of this scarce resource is increasingly challenging and complex. Striking an acceptable balance between efficient use of (utility) and fair access to (equity) the limited supply of donated kidneys raises controversial but important debates at ethical, medical, and social levels. There is no international consensus on the recipient and donor factors that should be considered in the kidney allocation process. There is a general trend toward a reduction in the influence of human leukocyte antigen mismatch and an increase in the importance of other factors shown to affect posttransplant outcomes, such as cold ischemia, duration of dialysis, donor and recipient age, and comorbidity. Increased consideration of equity has led to improved access to transplantation for disadvantaged patient groups. There has been an overall improvement in the transparency and accountability of allocation policies. Novel and contentious approaches in kidney allocation include the use of survival prediction scores as a criterion for accessing the waiting list and at the point of organ offering with matching of predicted graft and recipient survival. This review compares the diverse international approaches to deceased donor kidney allocation and their evolution over the last decade.

IntroductionThere 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 analysis6844 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 disseminationThe 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.

Table S1. Comorbidity variable definitions Comorbidity Definition (presence of any of the following) Diabetes • Any cause of diabetes • Type I diabetes -Insulin required from time of diagnosis • Type II diabetes -Treatment with diet-control, oral antidiabetic medication or insulin Ischaemic heart disease

Kidney transplantation is the optimal treatment for end-stage renal disease, but it is still severely limited by a lack of suitable organ donors. Kidneys from donation after circulatory death (DCD) donors have been used to increase transplant rates, but these organs are susceptible to cold ischemic injury in the storage period before transplantation, the clinical consequence of which is high rates of delayed graft function (DGF). Normothermic machine perfusion (NMP) is an emerging technique that circulates a warmed, oxygenated red-cell-based perfusate through the kidney to maintain near-physiological conditions. We conducted a randomized controlled trial to compare the outcome of DCD kidney transplants after conventional static cold storage (SCS) alone or SCS plus 1-h NMP. A total of 338 kidneys were randomly allocated to SCS (n = 168) or NMP (n = 170), and 277 kidneys were included in the final intention-to-treat analysis. The primary endpoint was DGF, defined as the requirement for dialysis in the first 7 d after transplant. The rate of DGF was 82 of 135 (60.7%) in NMP kidneys versus 83 of 142 (58.5%) in SCS kidneys (adjusted odds ratio (95% confidence interval) 1.13 (0.69–1.84); P = 0.624). NMP was not associated with any increase in transplant thrombosis, infectious complications or any other adverse events. A 1-h period of NMP at the end of SCS did not reduce the rate of DGF in DCD kidneys. NMP was demonstrated to be feasible, safe and suitable for clinical application. Trial registration number: ISRCTN15821205.