Cardiac Mortality in Kidney Transplant Patients: A Population-based Cohort Study 1988-2013 in Australia and New Zealand

Combination cell therapy leads to clonal deletion of donor-specific T cells in kidney transplant recipients

BACKGROUND

Induction of donor-specific tolerance is a promising approach to achieve long-term graft patency in transplantation with little to no maintenance immunosuppression. Changes to the recipient's T cell receptor (TCR) repertoire are understood to play a pivotal role in the establishment of a robust state of tolerance in chimerism-based transplantation protocols.

METHODS

We investigated changes to the TCR repertoires of patients participating in an ongoing prospective, controlled, phase I/IIa trial designed to evaluate the safety and efficacy of combination cell therapy in living donor kidney transplantation. Using high-throughput sequencing, we characterized the repertoires of six kidney recipients who also received bone marrow from the same donor (CKBMT), together with an infusion of polyclonal autologous Treg cells instead of myelosuppression.

FINDINGS

Patients undergoing combination cell therapy exhibited partial clonal deletion of donor-reactive CD4+ T cells at one, three, and six months post-transplant, compared to control patients receiving the same immunosuppression regimen but no cell therapy (p = 0.024). The clonality, R20 and turnover rates of the CD4+ and CD8+ TCR repertoires were comparable in both groups, showing our protocol caused no excessive repertoire shift or loss of diversity. Treg clonality was lower in the case group than in control (p = 0.033), suggesting combination cell therapy helps to preserve Treg diversity.

INTERPRETATION

Overall, our data indicate that combining Treg cell therapy with CKBMT dampens the alloimmune response to transplanted kidneys in humans in the absence of myelosuppression.

FUNDING

This study was funded by the Vienna Science and Technology Fund (WWTF).

Glucagon-like Peptide 1 Receptor Agonists and Cardiovascular Outcomes in Solid Organ Transplant Recipients With Diabetes Mellitus

BACKGROUND

Glucagon-like peptide 1 receptor agonists (GLP1-RAs) reduce cardiovascular events and mortality in type 2 diabetes. Limited data are available on diabetes treatment after solid organ transplantation. We aimed to explore the effect of GLP1-RAs on cardiovascular outcomes in transplanted recipients with diabetes.

METHODS

We extracted data on adult transplant recipients (kidney, lungs, liver, heart) insured in a large health maintenance organization. Death-censored patients with diabetes treated with GLP1-RAs were matched with nonusers. The primary outcome was a composite of major cardiovascular events (MACEs): a nonfatal cardiac event (myocardial infarction, stable/unstable angina, coronary bypass, and coronary angiography), ischemic stroke and all-cause mortality. Secondary outcomes were MACE or peripheral vascular disease (MACE-PVD), and all-cause mortality. Safety outcomes included biliopancreatic adverse events.

RESULTS

We included 318 patients (69% males, average age 58.3 ± 11.0 y) with a 3.1-y median follow-up. The incidence of MACE was 101 of 1000 patient-years in GLP1-RAs users compared with 134 of 1000 in controls (hazard ratio [HR] 0.46; 95% confidence interval [CI], 0.27-0.78). GLP1-RAs similarly reduced the risk of MACE-PVD (HR 0.53; 95% CI, 0.33-0.88) and the risk of all-cause mortality (HR 0.39; 95% CI, 0.18-0.84). Biliopancreatic adverse events occurred less in GLP1-RA users.

CONCLUSIONS

Transplant recipients with diabetes who used GLP1-RAs had lower risks for MACE and all-cause mortality. These results may profoundly implicate the daily management of posttransplant recipients with diabetes, a population with a high prevalence of cardiometabolic risk factors and cardiovascular death. Transplant patients are usually excluded from randomized controlled trials and, hence might be undertreated with disease-modifying drugs. Larger prospective studies are needed in this unique population.

Outcomes and management of kidney transplant recipients with Fabry disease: a review

Fabry disease is an X-linked inheritable lysosomal storage disease caused by various mutations of the galactosidase α gene resulting in α-galactosidase deficiency. Chronic kidney disease (CKD) is one of the most significant consequences of Fabry disease, with risk of end-stage kidney disease (ESKD) in this population. Like for other patients with ESKD, kidney transplant is the optimal treatment for Fabry disease patients with ESKD. However, enzyme replacement therapy and newer Fabry disease treatments remain important to mitigate other end organ damage such as cardiomyopathy post transplantation. This review is a primer on Fabry disease, which examines the outcomes of disease in the context of kidney transplant prior to, and during, the enzyme replacement treatment era, medical treatment of kidney transplant recipients with Fabry disease, and progress in screening studies.

Sex disparities in mortality and cardiovascular outcomes in chronic kidney disease

Sex (biologically determined) and gender (socially constructed) modulate manifestations and prognosis of a vast number of diseases, including cardiovascular disease (CVD) and chronic kidney disease (CKD). CVD remains the leading cause of death in CKD patients. Population-based studies indicate that women present a higher prevalence of CKD and experience less CVD than men in all CKD stages, although this is not as clear in patients on dialysis or transplantation. When compared to the general population of the same sex, CKD has a more negative impact on women on kidney replacement therapy. European women on dialysis or recipients of kidney transplants have life expectancy up to 44.8 and 19.8 years lower, respectively, than their counterparts of similar age in the general population. For men, these figures stand at 37.1 and 16.5 years, representing a 21% to 20% difference, respectively. Hormonal, genetic, societal, and cultural influences may contribute to these sex-based disparities. To gain a more comprehensive understanding of these differences and their implications for patient care, well-designed clinical trials that involve a larger representation of women and focus on sex-related variables are urgently needed. This narrative review emphasizes the importance of acknowledging the epidemiology and prognosis of sex disparities in CVD among CKD patients. Such insights can guide research into the underlying pathophysiological mechanisms, leading to optimized treatment strategies and ultimately, improved clinical outcomes.

Trends and Specific Causes of Cardiovascular Mortality after Kidney Transplantation in Finland

BACKGROUND

Cardiovascular diseases are an important cause of mortality in patients who have undergone kidney transplantation, but the knowledge on trends of cardiovascular mortality and specific causes of cardiovascular death among these patients is scarce.

METHODS

Our aim was to compare the cardiovascular mortality rates after kidney transplantation in Finland between 1990-1999, 2000-2009, and 2010-2019 using data from the Finnish Registry for Kidney Diseases. We analyzed 1-year and long-term cardiovascular mortality rates as well as the specific causes of cardiovascular death and the trends in them.

RESULTS

In total, 4946 patients underwent first kidney transplantation in 1990-2019. During the follow-up time (median 8.3 years, interquartile range 4.0-14.5), there were 1392 deaths, of which 582 were cardiovascular deaths. In an unadjusted Cox regression model, the risk of long-term cardiovascular mortality was similar in the different periods. However, when adjusted for age, sex, duration of dialysis, and cause of kidney disease, the long-term cardiovascular mortality risk was significantly lower in 2000-2009 and 2010-2019 (hazard ratio 0.60 [95% confidence interval, 0.49 to 0.73] and hazard ratio 0.51 [95% confidence interval, 0.39 to 0.66], respectively) compared with 1990-1999. The results were similar regarding 1-year cardiovascular mortality. The distribution of different causes of cardiovascular death remained unchanged during the study period, with coronary artery disease accounting for 47% of deaths. During the first year after transplantation, pulmonary embolisms and arrhythmias were more common than in the long term.

CONCLUSIONS

Cardiovascular disease remained the most common cause of death in kidney transplant recipients, but adjusted cardiovascular mortality risk has decreased significantly during the past three decades. Coronary artery disease was the most frequent cause of cardiovascular death, and the proportion of coronary artery disease-related cardiovascular deaths increased after the first year after transplantation.

Benefits of statin therapy within a year after kidney transplantation

Cardiovascular disease remains a leading cause of morbidity and mortality after kidney transplantation (KT). Although statins reduce cardiovascular risk and have renal benefits in the general population, their effects on KT recipients are not well-established. We studied the effects of early statin use (within 1-year post-transplantation) on long-term outcomes in 714 KT recipients from the Korean cohort study for outcome in patients with KT. Compared with the control group, statin group recipients were significantly older, had a higher body mass index, and had a higher prevalence of diabetes mellitus. During a median follow-up of 85 months, 74 graft losses occurred (54 death-censored graft losses and 20 deaths). Early statin use was independently associated with lower mortality (hazard ratio, 0.280; 95% confidence interval 0.111-0.703) and lower death-censored graft loss (hazard ratio, 0.350; 95% confidence interval 0.198-0.616). Statin therapy significantly reduced low-density lipoprotein cholesterol levels but did not decrease the risk of major adverse cardiovascular events. Biopsy-proven rejection and graft renal function were not significantly different between statin and control groups. Our findings suggest that early statin use is an effective strategy for reducing low-density lipoprotein cholesterol and improving patient and graft survival after KT.

Cardiovascular Outcomes in De Novo Kidney Transplant Recipients Receiving Everolimus and Reduced Calcineurin Inhibitor or Standard Triple Therapy: 24-month Post Hoc Analysis From TRANSFORM Study

BACKGROUND

The comparative impact of everolimus (EVR)-based regimens versus standard of care (mycophenolic acid+standard calcineurin inhibitor [MPA+sCNI]) on cardiovascular outcomes in de novo kidney transplant recipients (KTRs) is poorly understood. The incidence of major adverse cardiac events (MACEs) in KTRs receiving EVR+reduced CNI (rCNI) or MPA+sCNI from the TRANSplant eFficacy and safety Outcomes with an eveRolimus-based regiMen study was evaluated.

METHODS

The incidence of MACE was determined for all randomized patients receiving at least 1 dose of the study drug. Factors associated with MACEs were determined by logistic regression. Risk of MACE out to 3 y post-study was calculated using the Patient Outcome in Renal Transplantation equation.

RESULTS

MACE occurred in 81 of 1014 (8.0%; EVR+rCNI) versus 89 of 1012 (8.8%; MPA+sCNI) KTRs (risk ratio, 0.91 [95% confidence interval [CI], 0.68-1.21]). The incidence of circulatory death, myocardial infarction, revascularization, or angina was similar between the arms. Incidence of MACE was similar between EVR+rCNI and MPA+sCNI arms with a higher incidence in prespecified risk groups: older age, pretransplant diabetes (15.1% versus 15.9%), statin use (8.5% versus 10.8%), and low estimated glomerular filtration rate (Month 2 estimated glomerular filtration rate <30 versus >60 mL/min/1.73 m 2 ; odds ratio, 2.23 [95% CI, 1.02-4.86]; P = 0.044), respectively. Predicted risk of MACE within 3 y of follow-up did not differ between the treatment arms.

CONCLUSIONS

Cardiovascular morbidity and mortality were similar between de novo KTRs receiving EVR+rCNI and MPA+sCNI. EVR+rCNI is a viable alternative to the current standard of care in KTRs.

Kidney Transplant Outcomes in Elderly Population: A Systematic Review and Meta-analysis

Context

Owing to population ageing, a growing number of kidney transplants (KTs) in elderly population are being performed. KT is the best treatment for patients with end-stage renal disease (ESRD). However, in older patients, the decision between dialysis and KT can be difficult due to potential inferior outcomes. Few studies have been published addressing this issue, and literature outcomes are controversial.

Objective

To conduct a systematic review and meta-analysis to appraise the evidence about outcomes of KT in elderly patients (>70 yr).

Evidence acquisition

A systematic review and meta-analysis (PROSPERO registration: CRD42022337038) was performed. Search was conducted on PubMed and LILACS databases. Comparative and noncomparative studies addressing outcomes (overall survival [OS], graft survival [GS], complications, delayed graft function [DGF], primary nonfunction, graft loss, estimated glomerular filtrate rate, or acute rejection) of KT in people older than 70 yr were included.

Evidence synthesis

Of the 10 357 yielded articles, 19 met the inclusion criteria (18 observational studies, one prospective multicentre study, and no randomised controlled trials), enrolling a total of 293 501 KT patients. Comparative studies reporting enough quantitative data for target outcomes were combined. There were significant inferior 5-yr OS (relative risk [RR], 1.66; 95% confidence interval [CI], 1.18-2.35) and 5-yr GS in the elderly group (RR, 1.37; 95% CI, 1.14-1.65) to those in the <70-yr group. Short-term GS at 1 and 3 yr was similar between groups, and similar findings occurred with DGF, graft loss, and acute rejection rates. Few data about postoperative complications were reported.

Conclusions

Elderly recipients have worse OS at all time points and long-term GS compared with younger recipients (<70 yr). Postoperative complications were under-reported and could not be assessed. The DGF, acute rejection, death with functioning graft, and graft loss were not inferior in elderly recipients. Geriatric assessment in this setting might be useful for selecting better elderly candidates for KT.

Patient summary

Compared with younger population, kidney transplant in elderly patients has inferior patient and graft survival outcomes in the long term.

Plasma Copper Concentration Is Associated with Cardiovascular Mortality in Male Kidney Transplant Recipients

Kidney transplant recipients (KTR) are at increased risk of cardiovascular mortality. We investigated whether, in KTR, post-transplantation copper status is associated with the risk of cardiovascular mortality and potential effect modification by sex. In this cohort study, plasma copper was measured using mass spectrometry in extensively-phenotyped KTR with a functioning allograft >1-year. Cox regression analyses with the inclusion of multiplicative interaction terms were performed. In 660 KTR (53 ± 13 years old, 56% male), the median baseline plasma copper was 15.42 (IQR 13.53-17.63) µmol/L. During a median follow-up of 5 years, 141 KTR died, 53 (38%) due to cardiovascular causes. Higher plasma copper was associated with an increased risk of cardiovascular mortality in the overall KTR population (HR 1.37; 95% CI, 1.07-1.77 per 1-SD, p = 0.01). Sex was a significant effect modifier of this association (P_interaction = 0.01). Among male KTR, higher plasma copper concentration was independently associated with a two-fold higher risk of cardiovascular mortality (HR 2.09; 95% CI, 1.42-3.07 per 1-SD, p < 0.001). Among female KTR, this association was absent. This evidence offers a rationale for considering a sex-specific assessment of copper's role in cardiovascular risk evaluation. Further studies are warranted to elucidate whether copper-targeted interventions may decrease cardiovascular mortality in male KTR.

Echocardiogram screening in pediatric dialysis and transplantation

Transthoracic echocardiography is commonly used to identify structural and functional cardiac abnormalities that can be prevalent in childhood chronic kidney failure (KF). Left ventricular mass (LVM) increase is most frequently reported and may persist post-kidney transplant especially with hypertension and obesity. While systolic dysfunction is infrequently seen in childhood chronic KF, systolic strain identified by speckle tracking echocardiography has been frequently identified in dialysis and it can also persist post-transplant. Echocardiogram association with long-term outcomes has not been studied in childhood KF but there are many adult studies demonstrating associations between increased LVM, systolic dysfunction, strain, diastolic dysfunction, and cardiovascular events and mortality. There has been limited study of interventions to improve echocardiogram status. In childhood, improved blood pressure has been associated with better LVM, and conversion from hemodialysis to hemodiafiltration has been associated with better diastolic and systolic function. Whether long-term cardiac outcomes are also improved with these interventions is unclear. Echocardiography is a well-established technique, and regular use in childhood chronic KF seems justified. A case can be made to extend screening to include speckle tracking echocardiography and intradialytic studies in high-risk populations. Further longitudinal studies including these newer echocardiogram modalities, interventions, and long-term outcomes would help clarify recommendations for optimal use as a screening tool.

Cancer Mortality in People Receiving Dialysis for Kidney Failure: An Australian and New Zealand Cohort Study, 1980-2013

RATIONALE & OBJECTIVE

Cancer is a significant cause of morbidity in the population with kidney failure; however, cancer mortality in people undergoing dialysis has not been well described. We sought to compare cancer mortality in people on dialysis for kidney failure with cancer mortality in the general population.

STUDY DESIGN

A retrospective cohort study using linked health-administrative and dialysis registry data.

SETTING & PARTICIPANTS

All people receiving dialysis represented in the Australian and New Zealand Dialysis and Transplantation Registry, 1980-2013.

EXPOSURE

Dialysis; hemodialysis (HD) and peritoneal dialysis (PD).

OUTCOME

Death and underlying cause of death ascertained using health administrative data and classified using International Classification of Diseases, Tenth Revision, Australian Modification (ICD-10-AM) codes.

ANALYTICAL APPROACH

Indirect standardization on age at death, sex, year, and country to estimate standardized mortality ratios (SMR).

RESULTS

Over 269,598 person years of observation, 34,100 deaths occurred among 59,648 people on dialysis, including 3,677 cancer deaths. The relative risk of all-site cancer death in dialysis was twice (SMR, 2.4 [95% CI, 2.33-2.49]) that of the general population and highest for oral and pharynx cancers (SMR, 24.3 [95% CI, 18.0-31.5]) and multiple myeloma (SMR, 22.5 [95% CI, 20.3-23.9]). Women on dialysis had a significantly higher risk of all-site cancer mortality (SMR, 2.7 [95% CI, 2.59-2.89]) compared with men (SMR, 2.3 [95% CI, 2.17-2.36]) (P < 0.001). People on HD (SMR, 2.2 [95% CI, 2.11-2.30]) experienced greater excess deaths from all-site cancer compared with people on PD (SMR, 1.3 [95% CI, 1.23-1.44]). Excess deaths have gradually decreased over time for all-site, multiple myeloma, and kidney cancers (P < 0.001) but have not kept up with improvements in the general population. By contrast, among people receiving dialysis, excess deaths increased for colorectal and lung cancers (P < 0.001).

LIMITATIONS

Confirmation of cancer diagnoses and population incidence data were not available; inability to exclude pre-existing cancers.

CONCLUSIONS

People on dialysis experience excess all-site and site-specific cancer mortality compared with the general population. Mortality differs by modality type, age, and sex. Understanding the role of kidney failure and other morbidities in the treatment of cancer is important for shared decision-making regarding cancer treatments and identifying potential approaches to improve outcomes.

Cardiovascular Risk after Kidney Transplantation: Causes and Current Approaches to a Relevant Burden

Background. Cardiovascular disease is a frequent complication after kidney transplantation and represents the leading cause of mortality in this population. Material and Methods. We searched for the relevant articles in the National Institutes of Health library of medicine, transplant, cardiologic and nephrological journals. Results. The pathogenesis of cardiovascular disease in kidney transplant is multifactorial. Apart from non-modifiable risk factors, such as age, gender, genetic predisposition and ethnicity, several traditional and non-traditional modifiable risk factors contribute to its development. Traditional factors, such as diabetes, hypertension and dyslipidemia, may be present before and may worsen after transplantation. Immunosuppressants and impaired graft function may strongly influence the exacerbation of these comorbidities. However, in the last years, several studies showed that many other cardiovascular risk factors may be involved in kidney transplantation, including hyperuricemia, inflammation, low klotho and elevated Fibroblast Growth Factor 23 levels, deficient levels of vitamin D, vascular calcifications, anemia and poor physical activity and quality of life. Conclusions. The timely and effective treatment of time-honored and recently discovered modifiable risk factors represent the basis of the prevention of cardiovascular complications in kidney transplantation. Reduction of cardiovascular risk can improve the life expectancy, the quality of life and the allograft function and survival.

A population cohort analysis of English transplant centers indicates major adverse cardiovascular events after kidney transplantation

Major adverse cardiovascular event (MACE) rates immediately after kidney transplantation remain uncertain due to heterogeneous reporting in the literature. To clarify this, we retrospectively studied every eligible kidney transplant procedure performed in England between April 1, 2002 and March 31. 2018 with follow-up through August 31, 2019. The primary outcome of interest was MACE broadly defined as any hospital admission with myocardial infarction, stroke, unstable angina, heart failure, any coronary revascularisation procedure and/or any cardiovascular death. Among 30,325 kidney transplant recipients, MACE occurred in 781 within the first year after transplantation (2.6% of all kidney transplant procedures). Of these 781 events, 201 occurred during the index admission for kidney transplantation surgery representing 25.7% of all first-year MACE and 0.7% of all kidney transplant procedures. Kidney transplant recipients who suffered a non-fatal MACE within the first year had significantly decreased 1-, 3-, 5- and 10-year patient survival of 80.5%, 70.2%, 59.5% and 38.6% respectively, compared to 97.4%, 94.4%, 90.7% and 78.4% for kidney transplant recipients not developing MACE.. In an adjusted Cox proportional hazard model, non-fatal MACE within the first-year post-transplant was associated with significant long-term mortality risk (hazard ratio 2.59; 95% confidence interval 2.34-2.88). Kidney transplant recipients experiencing MACE during the index admission compared to subsequent admissions were differentiated by age, sex and previous cardiac history but had similar patient survival. These rates are significantly lower than those reported in North America. Thus, our data confirms MACE is not a benign post-transplant event and has a strong association with long-term mortality risk.

The role of renal resistive index as a prognostic tool in kidney transplantation: a systematic review

Background

In kidney transplant recipients (KTRs), observational data have reported conflicting findings about the utility of renal resistive index (RRI) in determining outcomes. We aimed to synthesize the current literature and determine the prognostic role of RRI in KTRs.

Methods

We conducted a systematic review to assess the role of RRI in predicting death, graft failure, graft function, and proteinuria. Of the 934 titles/abstracts reviewed, 26 studies were included. There was significant heterogeneity in RRI measurements and thresholds as well as in analytic methods and a meta-analysis could not be performed.

Results

All included studies were observational and included 7049 KTRs. Eight studies analyzed death, of which five reported a significant association with higher RRI. In the remaining three, small sample sizes and lower/multiple RRI thresholds may have limited detection of a statistically significant difference. Three studies investigated all-cause graft failure and an association with RRI was reported but varied by time of RRI measurement. Three out of five studies that analyzed a composite of patient and graft outcomes reported an association with RRI. Evidence analyzing death-censored graft failure, graft failure (unclear if death-censored or all-cause), measures of graft function, and proteinuria were conflicting. Most studies had a moderate to high risk of bias.

Conclusions

RRI likely has a prognostic role in predicting patient outcomes, reflecting patient systemic vascular disease burden rather than graft hemodynamics. Since cardiovascular diseases are a major cause of death and graft loss, RRI may be explored as a non-invasive tool to risk stratify KTRs.

Cardiometabolic and Kidney Protection in Kidney Transplant Recipients With Diabetes: Mechanisms, Clinical Applications, and Summary of Clinical Trials

Kidney transplantation is the therapy of choice for patients with end-stage renal disease. Preexisting diabetes is highly prevalent in kidney transplant recipients (KTR), and the development of posttransplant diabetes is common because of a number of transplant-specific risk factors such as the use of diabetogenic immunosuppressive medications and posttransplant weight gain. The presence of pretransplant and posttransplant diabetes in KTR significantly and variably affect the risk of graft failure, cardiovascular disease (CVD), and death. Among the many available therapies for diabetes, there are little data to determine the glucose-lowering agent(s) of choice in KTR. Furthermore, despite the high burden of graft loss and CVD among KTR with diabetes, evidence for strategies offering cardiovascular and kidney protection is lacking. Recent accumulating evidence convincingly shows glucose-independent cardiorenal protective effects in non-KTR with glucose-lowering agents, such as sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor agonists. Therefore, our aim was to review cardiorenal protective strategies, including the evidence, mechanisms, and rationale for the use of these glucose-lowering agents in KTR with diabetes.

Use of Statins in Kidney Transplant Recipients in Norway

Kidney transplant recipients (KTRs) experience increased risk of cardiovascular disease. Guidelines recommend HMG-CoA reductase inhibitor (statin) therapy when tolerated. We aimed to study changes in the prescription of statins and patients’ adherence to treatment over time. A population-based observational study utilizing linked data from the Norwegian Renal Registry (national coverage of 99.9%) and the Norwegian Prescription Database was performed. Data from a total of 2250 first KTRs were included (mean age—54 years, 69% men). Dispensed prescriptions of statins and immunosuppressants for the period 2004–2016 for all first KTRs engrafted in the period 2005–2015 were analyzed. Seventy-two percent received statins the first year after kidney transplantation and the proportion increased with age. The proportion receiving a statin varied according to the time frame of transplantation (77% in 2005–2010 vs. 66% in 2012–2015). Among new users of statins, 82% of the patients were adherent both the second and third year after kidney transplantation, while the corresponding figure for those already receiving statins before transplantation was 97%. Statin continuation rates in KTRs were high. In conclusion, our findings show a slightly lower overall proportion of patients receiving statins after kidney transplants than the national target level of 80%. The proportion of statin users increased with the age of the KTRs but showed a decreasing trend as time progressed.