Diabetes Mellitus and Prediabetes on Kidney Transplant Waiting List- Prevalence,Metabolic Phenotyping and Risk Stratification Approach

Background

Despite a significant prognostic impact, little is known about disturbances in glucose metabolism among kidney transplant candidates. We assess the prevalence of diabetes mellitus (DM) and prediabetes on kidney transplant waiting list, its underlying pathophysiology and propose an approach for individual risk stratification.

Methods

All patients on active kidney transplant waiting list of a large European university hospital transplant center were metabolically phenotyped.

Results

Of 138 patients, 76 (55%) had disturbances in glucose metabolism. 22% of patients had known DM, 3% were newly diagnosed. 30% were detected to have prediabetes. Insulin sensitivity and-secretion indices allowed for identification of underlying pathophysiology and risk factors. Age independently affected insulin secretion, resulting in a relative risk for prediabetes of 2.95 (95%CI 1.38–4.83) with a cut-off at 48 years. Body mass index independently affected insulin sensitivity as a continuous variable.

Conclusions

The prevalence of DM or prediabetes on kidney transplant waiting list is as high as 55%, with more than one third of patients previously undiagnosed. Oral glucose tolerance test is mandatory to detect all patients at risk. Metabolic phenotyping allows for differentiation of underlying pathophysiology and provides a basis for early individual risk stratification and specific intervention to improve patient and allograft outcome.     

INDUCTIVE RISK AND JUSTICE IN KIDNEY ALLOCATION

How should UNOS deal with the presence of scientific controversies on the risk factors for organ rejection when designing its allocation policies? The answer I defend in this paper is that the more undesirable the consequences of making a mistake in accepting a scientific hypothesis, the higher the degree of confirmation required for its acceptance. I argue that the application of this principle should lead to the rejection of the hypothesis that ‘less than perfect’ Human Leucocyte Antigen (HLA) matches are an important determinant of kidney graft survival. The scientific community has been divided all along on the significance of partial antigen matches. Yet reliance on partial matches has emerged as one of the primary factors leading blacks to spend a much longer time than whites on the waiting list for kidneys, thereby potentially impacting the justice of the kidney allocation policy. My case study illustrates one of the legitimate roles non‐epistemic values can play in science and calls into question the ideal of a value‐free science.     

Equity of access to renal transplant waiting list and renal transplantation in Scotland: cohort study

Objective To examine the access to the renal transplant waiting list and renal transplantation in Scotland.Design Cohort study.Setting Renal and transplant units in Scotland.Participants 4523 adults starting renal replacement therapy in Scotland between 1 January 1989 and 31 December 1999.Main outcome measures Impact of age, sex, social deprivation, primary renal disease, renal or transplant unit, and geography on access to the waiting list and renal transplantation.Results 1736 of 4523 (38.4%) patients were placed on the waiting list for renal transplantation and 1095 (24.2%) underwent transplantation up to 31 December 2000, the end of the study period. Patients were less likely to be placed on the list if they were female, older, had diabetes, were in a high deprivation category, and were treated in a renal unit in a hospital with no transplant unit. Patients living furthest away from the transplant centre were listed more quickly. The only factors governing access to transplantation once on the list were age, primary renal disease, and year of listing. A significant centre effect was found in access to the waiting list and renal transplantation.Conclusions A major disparity exists in access to the renal transplant waiting list and renal transplantation in Scotland. Comorbidity may be an important factor.     

Computational Eurotransplant kidney allocation simulations demonstrate the feasibility and benefit of T-cell epitope matching

The EuroTransplant Kidney Allocation System (ETKAS) aims at allocating organs to patients on the waiting list fairly whilst optimizing HLA match grades. ETKAS currently considers the number of HLA-A, -B, -DR mismatches. Evidently, epitope matching is biologically and clinically more relevant. We here executed ETKAS-based computer simulations to evaluate the impact of epitope matching on allocation and compared the strategies. A virtual population of 400,000 individuals was generated using the National Marrow Donor Program (NMDP) haplotype frequency dataset of 2011. Using this population, a waiting list of 10,400 patients was constructed and maintained during simulation, matching the 2015 Eurotransplant Annual Report characteristics. Unacceptable antigens were assigned randomly relative to their frequency using HLAMatchmaker. Over 22,600 kidneys were allocated in 10 years in triplicate using Markov Chain Monte Carlo simulations on 32-CPU-core cloud-computing instances. T-cell epitopes were calculated using the www.pirche.com portal. Waiting list effects were evaluated against ETKAS for five epitope matching scenarios. Baseline simulations of ETKAS slightly overestimated reported average HLA match grades. The best balanced scenario maintained prioritisation of HLA A-B-DR fully matched donors while replacing the HLA match grade by PIRCHE-II score and exchanging the HLA mismatch probability (MMP) by epitope MMP. This setup showed no considerable impact on kidney exchange rates and waiting time. PIRCHE-II scores improved, whereas the average HLA match grade diminishes slightly, yet leading to an improved estimated graft survival. We conclude that epitope-based matching in deceased donor kidney allocation is feasible while maintaining equal balances on the waiting list.     

Waiting list management in general practice: a review of orthopaedic patients.

OBJECTIVE: To review all patients on a current general practice orthopaedic waiting list for outpatient appointments with regard to accuracy of the list, clinical priority, and need for further radiological investigation before hospital attendance. DESIGN: Record review by one general practitioner and a radiologist, and discussion with patients of management alternatives. SETTING: Six partner city centre urban fund-holding general practice, list size 8651 (29% low deprivation payment status). SUBJECTS: 116 adults on an orthopaedic waiting list. MAIN OUTCOME MEASURES: List accuracy (patient details and status on waiting list); clinical priority (severity of condition); further investigations (results of tests after radiological review). RESULTS: 32 patients (28%) were removed from the waiting list because of inaccuracies. 14 patients were considered to be high priority and referred to other hospitals by utilising waiting list initiative funds. Of these patients, five agreed to referral to another hospital (treatment completed on average within three months of rereferral), six did not wish to be rereferred, and two did not attend to discuss the offer and remained on the original waiting list. One prioritised patient had further radiological investigations, was reassured, and was taken off the waiting list. 10 patients had further investigations. These resulted in six patients being referred to other hospitals, three being taken off the waiting list, and one seeking private care. CONCLUSIONS: Systematic review of patients on an orthopaedic waiting list of one general practice, though time consuming, led to the identification of inaccuracies in the list and changes in management. Costs need further evaluation, but if the findings occur widely substantial benefits could be achieved for patients.     

Kidney transplantation in Canada, 1981-84.

The Canadian Renal Failure Register was established in 1980. Data have been collected annually for all Canadian patients in whom irreversible kidney failure developed and who required dialysis or transplantation. The authors present actuarial patient and graft survival rates for 1981-84. In 1984, patients with a functioning renal graft accounted for 43.9% of the patients with end-stage renal disease. The number of transplants performed increased from 482 in 1981 to 662 in 1984; however, 1,022 patients undergoing dialysis (25.2%) were on an active waiting list for a transplant at the end of 1984. Greater effort is needed to increase the transplantation rate.     

Long distance travel for routine elective surgery: questionnaire survey of patients' attitudes.

OBJECTIVE--To carry out an audit and assess the acceptability of long distance travel to patients on a lengthy surgical waiting list. DESIGN--Audit and questionnaire survey. SETTING--Military hospital in Wiltshire. PATIENTS--116 Patients on a general surgical waiting list at Leighton Hospital near Crewe. INTERVENTIONS--Preselection for medical fitness at a waiting list review clinic. RESULTS--Roughly half of patients offered the facility of travelling 120 miles (190 km) for their routine elective operation at the health authority''s expense accepted. The average waiting list time declared by the patients who travelled was 28 months, and 13 patients stated that their condition prevented them from working. Only four patients regretted their decision to participate in the scheme. Lack of visitors did not cause undue concern. CONCLUSIONS--Some patients did not agree to travel for their operation but almost all of those who did so found the scheme satisfactory. Some minor problems were encountered but these could probably be overcome by ensuring use of appropriate transport, extending the postoperative stay when necessary, and more careful selection of patients for an anaesthetic. For efficient use of theatre time in such schemes it is crucial that the operating consultant surgeon should be in charge of case selection.     

Acute Antibody-Mediated Rejection in Presence of MICA-DSA and Successful Renal Re-Transplant with Negative-MICA Virtual Crossmatch

The presence of donor-specific alloantibodies (DSAs) against the MICA antigen results in high risk for antibody-mediated rejection (AMR) of a transplanted kidney, especially in patients receiving a re-transplant. We describe the incidence of acute C4d+ AMR in a patient who had received a first kidney transplant with a zero HLA antigen mismatch. Retrospective analysis of post-transplant T and B cell crossmatches were negative, but a high level of MICA alloantibody was detected in sera collected both before and after transplant. The DSA against the first allograft mismatched MICA*018 was in the recipient. Flow cytometry and cytotoxicity tests with five samples of freshly isolated human umbilical vein endothelial cells demonstrated the alloantibody nature of patient’s MICA-DSA. Prior to the second transplant, a MICA virtual crossmatch and T and B cell crossmatches were used to identify a suitable donor. The patient received a second kidney transplant, and allograft was functioning well at one-year follow-up. Our study indicates that MICA virtual crossmatch is important in selection of a kidney donor if the recipient has been sensitized with MICA antigens.     

Superiority of B locus matching over other HLA matching in renal graft survival.

Graft survival after 348 consecutive first cadaver-donor renal transplants was significantly improved by HLA matching when recipients who had received pretransplant blood transfusions were matched with their kidney donor for two HLA-B locus antigens. No other type of HLA matching significantly improved graft survival in transfused recipients nor did any type of HLA matching in non-transfused recipients. Matching for one HLA-DR antigen had no benefit in transfused recipients. Only two patients received kidneys matched for both DR antigens and only two of those in whom DR matching had been performed had not been transfused. These results indicate that pretransplant blood transfusion and selection of graft recipients predominantly on the basis of HLA-B matching has significantly reduced the renal graft rejection rate in Newcastle upon Tyne over two years. Thus, HLA-B antigen matching should be adopted as the main criterion for kidney sharing between transplant centres.     

TRADING WITH THE WAITING‐LIST: THE JUSTICE OF LIVING DONOR LIST EXCHANGE

In a Living Donor List Exchange program, the donor makes his kidney available for allocation to patients on the postmortal waiting‐list and receives in exchange a postmortal kidney, usually an O‐kidney, to be given to the recipient he favours. The program can be a solution for a candidate donor who is unable to donate directly or to participate in a paired kidney exchange because of blood group incompatibility or a positive cross‐match. Each donation within an LDLE program makes an additional organ available for transplantation. But because most of the pairs making use of the program will be A/O incompatible, it will also tend to increase the waiting time for patients with blood group O, who already have the longest waiting time. It has therefore been objected that the program is materially unjust, because it further disadvantages the least advantaged. This objection appeals to John Rawls’ difference principle. However, the context for which Rawls proposed that difference principle, is significantly different from the present one. Applying the principle here amounts to a lop‐sided trade‐off between considerations of need and considerations of overall utility. Considerations of formal justice, however, may lead to a stronger objection to LDLE programs. Such a program means that one O‐patient on the waiting list is exempted from the application of the general criteria used in constructing the list because he has a special bargaining advantage. This objection is spelled out and weighed against the obvious attraction of LDLE in a situation of (extreme) organ scarcity.     

Preservation methods for kidney and liver

With the successful testing of the immunosuppressive effects of cyclosporine in transplant patients in 1978, the field of organ transplants began an exponential growth. With that, the field of organ preservation became increasingly important as the need to increase preservation time and improve graft function became paramount. However, for every patient that receives a transplanted organ, there are 4 more on the waiting list. In addition, a patient dies from the lack of a transplant almost every 1½ hour. To alleviate this donor crisis, there is a need to expand the donor pool to marginal donor organs. The main reason these organs are underutilized is because the current method of static preservation, simple cold storage, is ineffective. This article will provide a general review of the methods of preservation including simple cold storage, hypothermic machine perfusion, normothermic machine perfusion, and oxygen persufflation. In addition, the article will provide a review of how these dynamic preservation methods have improved the recovery and preservation of marginal donor organs including donation after cardiac death and fatty livers.     

Influence of Socio-Economic Inequalities on Access to Renal Transplantation and Survival of Patients with End-Stage Renal Disease

BackgroundPublic and scientific concerns about the social gradient of end-stage renal disease and access to renal replacement therapies are increasing. This study investigated the influence of social inequalities on the (i) access to renal transplant waiting list, (ii) access to renal transplantation and (iii) patients’ survival.MethodsAll incident adult patients with end-stage renal disease who lived in Bretagne, a French region, and started dialysis during the 2004–2009 period were geocoded in census-blocks. To each census-block was assigned a level of neighborhood deprivation and a degree of urbanization. Cox proportional hazards models were used to identify factors associated with each study outcome.ResultsPatients living in neighborhoods with low level of deprivation had more chance to be placed on the waiting list and less risk of death (HR = 1.40 95%CI: [1.1–1.7]; HR = 0.82 95%CI: [0.7–0.98]), but this association did not remain after adjustment for the patients’ clinical features. The likelihood of receiving renal transplantation after being waitlisted was not associated with neighborhood deprivation in univariate and multivariate analyses.ConclusionsIn a mixed rural and urban French region, patients living in deprived or advantaged neighborhoods had the same chance to be placed on the waiting list and to undergo renal transplantation. They also showed the same mortality risk, when their clinical features were taken into account.     

Waiting list statistics. III. Comparison of two measures of waiting times.

The length of time that patients spend on waiting lists is a topic of current concern. Calculating the proportion of patients who have been on a waiting list for a long time by taking a census of patients on the list at a single point in time will tend to yield a higher estimate than that obtained by calculating waiting times of patients admitted to hospital during a period of time. To illustrate this point the waiting times of patients in the Oxford region as measured by SBH 203 returns ("census" data) were compared with those as measured by the Hospital Activity Analysis ("event" data). As expected, the SBH 203 census returns showed a higher proportion of patients who had waited over a year compared with the "event" measure of all admissions. This difference, which is analagous to the difference between prevalence and incidence in epidemiology, should be considered when using data from these sources to calculate waiting times.     

Effects of aging on the kidney.

A host of abnormalities of renal structure and function accompany advancing age. This presentation briefly surveys the renal anatomical and functional changes associated with senescence. Four areas of renal functional change have been selected for in-depth discussion: a) renal blood flow; b) glomerular filtration rate; c) renal sodium handling; and d) renal concentrating ability. The methodologic considerations including population selection which confound the assessment of the effects of aging on renal function are discussed. In addition, the functional changes associated with senescence are discussed in the context of longitudinal studies and studies utilizing appropriate patient cohorts, including potential kidney transplant donors. The clinical implications of senescent changes with regard to adjusting "normative" standards to fit the age of the patient are addressed. Furthermore, the implications of age-related renal functional alterations in predisposing the elderly patient to a number of fluid and electrolyte derangements are considered.--Epstein, M. Effects of aging on the kidney.     

Preservation methods for kidney and liver

With the successful testing of the immunosuppressive effects of cyclosporine in transplant patients in 1978, the field of organ transplants began an exponential growth. With that, the field of organ preservation became increasingly important as the need to increase preservation time and improve graft function became paramount. However, for every patient that receives a transplanted organ, there are four more on the waiting list. In addition, a patient dies from the lack of a transplant almost every 1½ hour. To alleviate this donor crisis, there is a need to expand the donor pool to marginal donor organs. The main reason these organs are underutilized is because the current method of static preservation, simple cold storage, is ineffective. This article will provide a general review of the methods of preservation including simple cold storage, hypothermic machine perfusion, normothermic machine perfusion, and oxygen persufflation. In addition, the article will provide a review of how these dynamic preservation methods have improved the recovery and preservation of marginal donor organs including Donation after Cardiac Death and Fatty livers.     

Pre-Transplant Donor-Specific T-Cell Alloreactivity Is Strongly Associated with Early Acute Cellular Rejection in Kidney Transplant Recipients Not Receiving T-Cell Depleting Induction Therapy

Preformed T-cell immune-sensitization should most likely impact allograft outcome during the initial period after kidney transplantation, since donor-specific memory T-cells may rapidly recognize alloantigens and activate the effector immune response, which leads to allograft rejection. However, the precise time-frame in which acute rejection is fundamentally triggered by preformed donor-specific memory T cells rather than by de novo activated naïve T cells is still to be established. Here, preformed donor-specific alloreactive T-cell responses were evaluated using the IFN-γ ELISPOT assay in a large consecutive cohort of kidney transplant patients (n = 90), to assess the main clinical variables associated with cellular sensitization and its predominant time-frame impact on allograft outcome, and was further validated in an independent new set of kidney transplant recipients (n = 67). We found that most highly T-cell sensitized patients were elderly patients with particularly poor HLA class-I matching, without any clinically recognizable sensitizing events. While one-year incidence of all types of biopsy-proven acute rejection did not differ between T-cell alloreactive and non-alloreactive patients, Receiver Operating Characteristic curve analysis indicated the first two months after transplantation as the highest risk time period for acute cellular rejection associated with baseline T-cell sensitization. This effect was particularly evident in young and highly alloreactive individuals that did not receive T-cell depletion immunosuppression. Multivariate analysis confirmed preformed T-cell sensitization as an independent predictor of early acute cellular rejection. In summary, monitoring anti-donor T-cell sensitization before transplantation may help to identify patients at increased risk of acute cellular rejection, particularly in the early phases after kidney transplantation, and thus guide decision-making regarding the use of induction therapy.     

肾移植受者生活质量和健康素养现状调查及影响因素分析

目的:调查肾移植受者生活质量(QOL)、健康素养(HL)现状,并分析其QOL、HL的影响因素。方法:选择我院2015年1月～2016年1月收治的369例肾移植受者为研究对象,采用自制问卷结合病历信息的方式收集入选患者的临床资料,分别采用健康状况调查简表(SF-36)、中文版成人快速健康素养评估量表(REALAM-T)对肾移植受者的QOL、HL的现状进行调查,并分析肾移植受者QOL、HL的影响因素。结果:369例肾移植受者QOL评分为(561.08±54.95)分,HL评分为(62.75±5.26)分,其中288例(78.05%)患者处于HL充足水平,56例(15.18%)患者处于HL临界水平,25例(6.78%)患者处于HL缺乏水平。单因素分析结果显示,不同婚姻状况、家庭人均月收入、文化程度、费用支付方式、移植肾来源、移植术后时间的肾移植受者QOL评分比较差异有统计学意义(P0.05);不同家庭人均月收入、文化程度、费用支付方式、移植肾来源、移植术后时间的肾移植受者HL评分比较差异有统计学意义(P0.05)。多元线性回归分析显示,家庭人均月收入、费用支付方式、移植肾来源、移植术后时间是肾移植受者QOL的影响因素(P0.05),文化程度、移植肾来源、移植术后时间是肾移植受者HL的影响因素(P0.05)。结论:肾移植受者QOL较差,HL整体不高,家庭人均月收入、费用支付方式、移植肾来源、移植术后时间是肾移植受者QOL的影响因素,文化程度、移植肾来源、移植术后时间是肾移植受者HL的影响因素,临床应根据以上因素采取针对性的措施,以提高肾移植受者的QOL和HL。     

Access to adult liver transplantation in Canada: a survey and ethical analysis.

OBJECTIVES: To describe the substantive and procedural criteria used for placing patients on the waiting list for liver transplantation and for allocating available livers to patients on the waiting list; to identify principal decision-makers and the main factors limiting liver transplantation in Canada; and to examine how closely cadaveric liver allocation resembles theoretic models of source allocation. DESIGN: Mailed survey. PARTICIPANTS: Medical directors of all seven Canadian adult liver transplantation centres, or their designates. Six of the questionnaires were completed. OUTCOME MEASURES: Relative importance of substantive and procedural criteria used to place patients in the waiting list for liver transplantation and to allocate available livers. Identification of principal decision-makers and main limiting factors to adult liver transplantation. RESULTS: Alcoholism, drug addiction, HIV positivity, primary liver cancer, noncompliance and hepatitis B were the most important criteria that had a negative influence on decisions to place patients on the waiting list for liver transplantation. Severity of disease and urgency were the most important criteria used for selecting patients on the waiting list for transplantation. Criteria that were inconsistent across the centres included social support (for deciding who is placed on the waiting list) and length of time on the waiting list (for deciding who is selected from the list). Although a variety of people were reported as being involved in these decisions, virtually all were reported to be health to be health care professionals. Thirty-seven patients died while waiting for liver transplantation in 1991; the scarcity of cadaveric livers was the main limiting factor. CONCLUSIONS: Criteria for resource allocation decisions regarding liver transplantation are generally consistent among the centres across Canada, although some important inconsistencies remain. Because patients die while on the waiting list and because the primary limiting factor is organ supply, increased organ acquisition efforts are needed.     

Operating room scheduling and rescheduling: a rolling horizon approach

In this work we consider the problem of selecting a set of patients among a given waiting list of elective patients and assigning them to a set of available operating room blocks. We assume a block scheduling strategy in which the number and the length of available blocks are given. As each block is related to a specific day, by assigning a patient to a block his/her surgery date is fixed, as well. Each patient is characterized by a recommended maximum waiting time and an uncertain surgery duration. In practical applications, new patients enter the waiting list continuously. Patient selection and assignment is performed by surgery departments on a short-term, usually a week, regular base. We propose a so-called rolling horizon approach for the patient selection and assignment. At each iteration short-term patient assignment is decided. However, in a look-ahead perspective, a longer planning horizon is considered when looking for the patient selection. The mid-term assignment over the next \(n\) weeks is generated by solving an ILP problem, minimizing a penalty function based on total waiting time and tardiness of patients. The approach is iteratively applied by shifting ahead the mid-term planning horizon. When applying the first week solution, unpredictable extensions of surgeries may disrupt the schedule. Such disruptions are recovered in the next iteration: the mid-term solution is rescheduled limiting the number of variations from the previously computed plan. Besides, the approach allows to deal with new patient arrivals. To keep limited the number of disruptions due to uncertain surgery duration, we propose also a robust formulation of the ILP problem. The deterministic and the robust formulation based frameworks are compared over a set of instances, including different stochastic realization of surgery times.     

Waiting for organ transplantation: results of an analysis by an Institute of Medicine Committee

One of the most visible and contentious issues regarding the fairness of the original system of organ procurement and allocation is the argument that it resulted in great disparities in the total amount of time a patient waited for an organ (i.e. the time from registration at a transplantation center to transplant), depending on where he or she lived. In an attempt to resolve this debate, Congress charged the National Academy of Sciences, Institute of Medicine to perform an independent study of the original system and proposed rule changes. In an analysis of approximately 68,000 transplant waiting list records, the committee developed several conclusions and recommendations largely specific to liver transplantation policies. The purpose of this paper is to describe both the results of the study and the statistical foundations of the mixed-effects multinomial logistic regression model that led to the committee's conclusions.