Pharmacomicrobiomics: Immunosuppressive Drugs and Microbiome Interactions in Transplantation

The human microbiome is associated with human health and disease. Exogenous compounds, including pharmaceutical products, are also known to be affected by the microbiome, and this discovery has led to the field of pharmacomicobiomics. The microbiome can also alter drug pharmacokinetics and pharmacodynamics, possibly resulting in side effects, toxicities, and unanticipated disease response. Microbiome-mediated effects are referred to as drug-microbiome interactions (DMI). Rapid advances in the field of pharmacomicrobiomics have been driven by the availability of efficient bacterial genome sequencing methods and new computational and bioinformatics tools. The success of fecal microbiota transplantation for recurrent Clostridioides difficile has fueled enthusiasm and research in the field. This review focuses on the pharmacomicrobiome in transplantation. Alterations in the microbiome in transplant recipients are well documented, largely because of prophylactic antibiotic use, and the potential for DMI is high. There is evidence that the gut microbiome may alter the pharmacokinetic disposition of tacrolimus and result in microbiome-specific tacrolimus metabolites. The gut microbiome also impacts the enterohepatic recirculation of mycophenolate, resulting in substantial changes in pharmacokinetic disposition and systemic exposure. The mechanisms of these DMI and the specific bacteria or communities of bacteria are under investigation. There are little or no human DMI data for cyclosporine A, corticosteroids, and sirolimus. The available evidence in transplantation is limited and driven by small studies of heterogeneous designs. Larger clinical studies are needed, but the potential for future clinical application of the pharmacomicrobiome in avoiding poor outcomes is high.

Fracture Risk Among Living Kidney Donors 25 Years After Donation

Importance

Living kidney donors may have an increased risk of fractures due to reductions in kidney mass, lower concentrations of serum 1,25-dihydroxyvitamin D, and secondary increases in serum parathyroid hormone.

Objective

To compare the overall and site-specific risk of fractures among living kidney donors with strictly matched controls from the general population who would have been eligible to donate a kidney but did not do so.

Design, Setting, and Participants

This survey study was conducted between December 1, 2021, and July 31, 2023. A total of 5065 living kidney donors from 3 large transplant centers in Minnesota were invited to complete a survey about their bone health and history of fractures, and 16 156 population-based nondonor controls without a history of comorbidities that would have precluded kidney donation were identified from the Rochester Epidemiology Project and completed the same survey. A total of 2132 living kidney donors and 2014 nondonor controls responded to the survey. Statistical analyses were performed from May to August 2023.

Exposure

Living kidney donation.

Main Outcomes and Measures

The rates of overall and site-specific fractures were compared between living kidney donors and controls using standardized incidence ratios (SIRs).

Results

At the time of survey, the 2132 living kidney donors had a mean (SD) age of 67.1 (8.9) years and included 1245 women (58.4%), and the 2014 controls had a mean (SD) age of 68.6 (7.9) years and included 1140 women (56.6%). The mean (SD) time between donation or index date and survey date was 24.2 (10.4) years for donors and 27.6 (10.7) years for controls. The overall rate of fractures among living kidney donors was significantly lower than among controls (SIR, 0.89; 95% CI, 0.81-0.97). However, there were significantly more vertebral fractures among living kidney donors than among controls (SIR, 1.42; 95% CI, 1.05-1.83).

Conclusions and Relevance

This survey study found a reduced rate of overall fractures but an excess of vertebral fractures among living kidney donors compared with controls after a mean follow-up of 25 years. Treatment of excess vertebral fractures with dietary supplements such as vitamin D3 may reduce the numbers of vertebral fractures and patient morbidity.

Transportability of causal inference under random dynamic treatment regimes for kidney-pancreas transplantation

A difficult decision for patients in need of kidney-pancreas transplant is whether to seek a living kidney donor or wait to receive both organs from one deceased donor. The framework of dynamic treatment regimes (DTRs) can inform this choice, but a patient-relevant strategy such as "wait for deceased-donor transplant" is ill-defined because there are multiple versions of treatment (i.e., wait times, organ qualities). Existing DTR methods average over the distribution of treatment versions in the data, estimating survival under a "representative intervention." This is undesirable if transporting inferences to a target population such as patients today, who experience shorter wait times thanks to evolutions in allocation policy. We, therefore, propose the concept of a generalized representative intervention (GRI): a random DTR that assigns treatment version by drawing from the distribution among strategy compliers in the target population (e.g., patients today). We describe an inverse-probability-weighted product-limit estimator of survival under a GRI that performs well in simulations and can be implemented in standard statistical software. For continuous treatments (e.g., organ quality), weights are reformulated to depend on probabilities only, not densities. We apply our method to a national database of kidney-pancreas transplant candidates from 2001-2020 to illustrate that variability in transplant rate across years and centers results in qualitative differences in the optimal strategy for patient survival.

Report From a Multidisciplinary Symposium on the Future of Living Kidney Donor Transplantation

Virtually all clinicians agree that living donor renal transplantation is the optimal treatment for permanent loss of kidney function. Yet, living donor kidney transplantation has not grown in the United States for more than 2 decades. A virtual symposium gathered experts to examine this shortcoming and to stimulate and clarify issues salient to improving living donation. The ethical principles of rewarding kidney donors and the limits of altruism as the exclusive compelling stimulus for donation were emphasized. Concepts that donor incentives could save up to 40 000 lives annually and considerable taxpayer dollars were examined, and survey data confirmed voter support for donor compensation. Objections to rewarding donors were also presented. Living donor kidney exchanges and limited numbers of deceased donor kidneys were reviewed. Discussants found consensus that attempts to increase living donation should include removing artificial barriers in donor evaluation, expansion of living donor chains, affirming the safety of live kidney donation, and assurance that donors incur no expense. If the current legal and practice standards persist, living kidney donation will fail to achieve its true potential to save lives.

The Organ Shortage Continues to Be a Crisis for Patients With End-stage Kidney Disease

This Viewpoint describes the organ shortage for patients with end-stage kidney disease despite increases in kidney donations between 2000 and 2021.

Long-term Outcomes Associated With Post-kidney Donation Pregnancy Complications

BACKGROUND

Kidney donors have increased risk of postdonation gestational hypertension (gHTN) and preeclampsia. In the general population, pregnancy complications are associated with long-term maternal risk. However, little data exist on whether donors with postdonation pregnancy-related complications have similar increased long-term risks. We studied whether postdonation gHTN, preeclampsia/eclampsia, or gestational diabetes (gDM) was associated with increased risk of developing hypertension, DM, cardiovascular disease, or estimated glomerular filtration rate <45 mL/min/1.73 m 2 .

METHODS

Postdonation pregnancies with complications were matched to pregnancies without complications based on time from donation. Incidence of outcomes was compared using sequential Cox regression with robust standard errors. Donors with predonation pregnancy complications were excluded. Models were adjusted for age at pregnancy, gravidity, year of donation, and family history of hypertension, DM, and heart disease.

RESULTS

Of the 384 donors with postdonation pregnancies (median [quartiles] follow-up of 27.0 [14.2-36.2] y after donation), 39 experienced preeclampsia/eclampsia, 29 gHTN without preeclampsia, and 17 gDM. Median interval from donation to first pregnancy with preeclampsia was 5.1 (2.9-8.6) y; for gHTN, 3.7 (1.9-7.8) y; and for gDM, 7.3 (3.7-10.3) y. Preeclampsia/eclampsia (hazard ratio [HR] 2.70; 95% confidence interval [CI], 1.53-4.77) and gHTN (HR 2.39; 95% CI, 1.24-4.60) were associated with development of hypertension. Preeclampsia/eclampsia (HR 2.15; 95% CI, 1.11-4.16) and gDM (HR 5.60; 95% CI, 1.41-22.15) were associated with development of DM. Pregnancy-related complications were not associated with increased risk of cardiovascular disease or estimated glomerular filtration rate <45 mL/min/1.73 m 2 .

CONCLUSIONS

In our single-center study, postdonation preeclampsia, gHTN, or gDM was associated with long-term risk of hypertension or DM.

Development and Validation of a Hypertension Risk Calculator for Living Kidney Donors

BACKGROUND

Ideally, when deciding whether to donate, kidney donor candidates would understand their long-term risks. Using single-center data (N = 4055; median [quartiles] follow-up: 18 [9-28] y), we developed a calculator for postdonation hypertension and validated it using long-term data from an external single-center cohort (N = 1189, median [quartiles] follow-up: 9 [5-17] y).

METHODS

Risk factors considered were routinely obtained at evaluation from donor candidates. Two modeling approaches were evaluated: Cox proportional hazards and random survival forest models. Cross-validation prediction error and Harrell's concordance-index were used to compare accuracy for model development. Top-performing models were assessed in the validation cohort using the concordance-index and net reclassification improvement.

RESULTS

In the development cohort, 34% reported hypertension at a median (quartiles) of 16 (8-24) y postdonation; and in the validation cohort, 29% reported hypertension after 17 (10-22) y postdonation. The most accurate model was a Cox proportional hazards model with age, sex, race, estimated glomerular filtration rate, systolic and diastolic blood pressure, body mass index, glucose, smoking history, family history of hypertension, relationship with recipient, and hyperlipidemia (concordance-index, 0.72 in the development cohort and 0.82 in the validation cohort).

CONCLUSIONS

A postdonation hypertension calculator was developed and validated; it provides kidney donor candidates, their family, and care team a long-term projection of hypertension risk that can be incorporated into the informed consent process.

Race-free estimated glomerular filtration rate equation in kidney transplant recipients: development and validation study

OBJECTIVE

To compare the performance of a newly developed race-free kidney recipient specific glomerular filtration rate (GFR) equation with the three current main equations for measuring GFR in kidney transplant recipients.

DESIGN

Development and validation study SETTING: 17 cohorts in Europe, the United States, and Australia (14 transplant centres, three clinical trials).

PARTICIPANTS

15 489 adults (3622 in development cohort (Necker, Saint Louis, and Toulouse hospitals, France), 11 867 in multiple external validation cohorts) who received kidney transplants between 1 January 2000 and 1 January 2021.

MAIN OUTCOME MEASURE

The main outcome measure was GFR, measured according to local practice. Performance of the GFR equations was assessed using P30 (proportion of estimated GFR (eGFR) within 30% of measured GFR (mGFR)) and correct classification (agreement between eGFR and mGFR according to GFR stages). The race-free equation, based on creatinine level, age, and sex, was developed using additive and multiplicative linear regressions, and its performance was compared with the three current main GFR equations: Modification of Diet in Renal Disease (MDRD) equation, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2009 equation, and race-free CKD-EPI 2021 equation.

RESULTS

The study included 15 489 participants, with 50 464 mGFR and eGFR values. The mean GFR was 53.18 mL/min/1.73m2 (SD 17.23) in the development cohort and 55.90 mL/min/1.73m2 (19.69) in the external validation cohorts. Among the current GFR equations, the race-free CKD-EPI 2021 equation showed the lowest performance compared with the MDRD and CKD-EPI 2009 equations. When race was included in the kidney recipient specific GFR equation, performance did not increase. The race-free kidney recipient specific GFR equation showed significantly improved performance compared with the race-free CKD-EPI 2021 equation and performed well in the external validation cohorts (P30 ranging from 73.0% to 91.3%). The race-free kidney recipient specific GFR equation performed well in several subpopulations of kidney transplant recipients stratified by race (P30 73.0-91.3%), sex (72.7-91.4%), age (70.3-92.0%), body mass index (64.5-100%), donor type (58.5-92.9%), donor age (68.3-94.3%), treatment (78.5-85.2%), creatinine level (72.8-91.3%), GFR measurement method (73.0-91.3%), and timing of GFR measurement post-transplant (72.9-95.5%). An online application was developed that estimates GFR based on recipient's creatinine level, age, and sex (https://transplant-prediction-system.shinyapps.io/eGFR_equation_KTX/).

CONCLUSION

A new race-free kidney recipient specific GFR equation was developed and validated using multiple, large, international cohorts of kidney transplant recipients. The equation showed high accuracy and outperformed the race-free CKD-EPI 2021 equation that was developed in individuals with native kidneys.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05229939.

The Minnesota attributable risk of kidney donation (MARKD) study: a retrospective cohort study of long-term (> 50 year) outcomes after kidney donation compared to well-matched healthy controls

BACKGROUND

There is uncertainty about the long-term risks of living kidney donation. Well-designed studies with controls well-matched on risk factors for kidney disease are needed to understand the attributable risks of kidney donation.

METHODS

The goal of the Minnesota Attributable Risk of Kidney Donation (MARKD) study is to compare the long-term (> 50 years) outcomes of living donors (LDs) to contemporary and geographically similar controls that are well-matched on health status. University of Minnesota (n = 4022; 1st transplant: 1963) and Mayo Clinic LDs (n = 3035; 1st transplant: 1963) will be matched to Rochester Epidemiology Project (REP) controls (approximately 4 controls to 1 donor) on the basis of age, sex, and race/ethnicity. The REP controls are a well-defined population, with detailed medical record data linked between all providers in Olmsted and surrounding counties, that come from the same geographic region and era (early 1960s to present) as the donors. Controls will be carefully selected to have health status acceptable for donation on the index date (date their matched donor donated). Further refinement of the control group will include confirmed kidney health (e.g., normal serum creatinine and/or no proteinuria) and matching (on index date) of body mass index, smoking history, family history of chronic kidney disease, and blood pressure. Outcomes will be ascertained from national registries (National Death Index and United States Renal Data System) and a new survey administered to both donors and controls; the data will be supplemented by prior surveys and medical record review of donors and REP controls. The outcomes to be compared are all-cause mortality, end-stage kidney disease, cardiovascular disease and mortality, estimated glomerular filtration rate (eGFR) trajectory and chronic kidney disease, pregnancy risks, and development of diseases that frequently lead to chronic kidney disease (e.g. hypertension, diabetes, and obesity). We will additionally evaluate whether the risk of donation differs based on baseline characteristics.

DISCUSSION

Our study will provide a comprehensive assessment of long-term living donor risk to inform candidate living donors, and to inform the follow-up and care of current living donors.

Higher number of tacrolimus dose adjustments in kidney transplant recipients who are extensive and intermediate CYP3A5 metabolizers

Kidney transplant recipients carrying the CYP3A5*1 allele have lower tacrolimus troughs, and higher dose requirements compared to those with the CYP3A5*3/*3 genotype. However, data on the effect of CYP3A5 alleles on post-transplant tacrolimus management are lacking. The effect of CYP3A5 metabolism phenotypes on the number of tacrolimus dose adjustments and troughs in the first 6 months post-transplant was evaluated in 78 recipients (64% Caucasians). Time to first therapeutic concentration, percentage of time in therapeutic range (TTR), and estimated glomerular filtration rate (eGFR) were also evaluated. Fifty-five kidney transplant recipients were CYP3A5 poor metabolizers (PM), 17 were intermediate metabolizers (IM), and 6 were extensive metabolizers (EM). Compared to PMs, EMs/IMs had significantly more dose adjustments (6.1 vs. 8.1, p = .015). Overall, 33.82% of trough measurements resulted in a dose change. There was no difference in the number of tacrolimus trough measurements between PMs and EM/IMs. The total daily tacrolimus dose requirements were higher in EMs and IMs compared to PMs (<.001). TTR was ∼50% in the PMs and EMs/IMs groups. CYP3A5 EM/IM metabolizers have more tacrolimus dose changes and higher dose requirements which increases clinical management complexity. Larger studies are needed to assess the cost and benefits of including genotyping data to improve clinical management.

The John S. Najarian symposium: The past, present, and future of surgery and transplantation, May 20, 2022, Minneapolis, MN

Dr John S Najarian (1927-2020), chairman of the Department of Surgery at the University of Minnesota from 1967 to 1993, was a pioneer in surgery, clinical immunology and transplantation. A Covid-delayed Festschrift was held in his honor on May 20, 2022. The speakers reflected on his myriad contributions to surgery, transplantation, and resident/fellow training, as well as current areas of ongoing research to improve clinical outcomes. Of note, Dr Najarian was a founder of the journal Clinical Transplantation.

A regulated system of incentives for living kidney donation: Clearing the way for an informed assessment

The kidney shortage continues to be a crisis for our patients. Despite numerous attempts to increase living and deceased donation, annually in the United States, thousands of candidates are removed from the kidney transplant waiting list because of either death or becoming too sick to transplant. To increase living donation, trials of a regulated system of incentives for living donation have been proposed. Such trials may show: (1) a significant increase in donation, and (2) that informed, incentivized donors, making an autonomous decision to donate, have the same medical and psychosocial outcomes as our conventional donors. Given the stakes, the proposal warrants careful consideration. However, to date, much discussion of the proposal has been unproductive. Objections commonly leveled against it: fail to engage with it; conflate it with underground, unregulated markets; speculate without evidence; and reason fallaciously, favoring rhetorical impact over logic. The present paper is a corrective. It identifies these common errors so they are not repeated, thus allowing space for an assessment of the proposal on its merits.

Long-term Medical Outcomes of Living Kidney Donors

Historically, to minimize risks, living kidney donors have been highly selected and healthy. Operative risks are well-defined, yet concern remains about long-term risks. In the general population, even a mild reduction in glomerular filtration rate (GFR) is associated with cardiovascular disease, chronic kidney disease, and end-stage kidney disease (ESKD). However, reduction in GFR in the general population is due to kidney or systemic disease. Retrospective studies comparing donors with matched general population controls have found no increased donor risk. Prospective studies comparing donors with controls (maximum follow-up, 9 years) have reported that donor GFR is stable or increases slightly, whereas GFR decreases in controls. However, these same studies identified metabolic and vascular donor abnormalities. There are a few retrospective studies comparing donors with controls. Each has limitations in selection of the control group, statistical analyses, and/or length of follow-up. One such study reported increased donor mortality; 2 reported a small increase in absolute risk of ESKD. Risk factors for donor ESKD are similar to those in the general population. Postdonation pregnancies are also associated with increased risk of hypertension and preeclampsia. There is a critical need for long-term follow-up studies comparing donors with controls from the same era, geographic area, and socioeconomic status who are healthy, with normal renal function on the date matching the date of donation, and are matched on demographic characteristics with the donors. These data are needed to optimize donor candidate counseling and informed consent.

Pre-kidney Donation Pregnancy Complications and Long-term Outcomes

BACKGROUND

Hypertension and diabetes are contraindications for living kidney donation in young candidates. However, little is known about the long-term outcomes of women who had these pregnancy-related complications and subsequently became donors. In the general population, gestational hypertension (GHtn), preeclampsia/eclampsia, and gestational diabetes (GDM) are associated with long-term risks.

METHODS

Donors with the specified predonation complication were matched to contemporary control donors with pregnancies without the complication using nearest neighbor propensity score matching. Propensity scores were estimated using logistic regression with covariates for gravidity, blood pressure, glucose, body mass index, age, and creatinine at donation, donation year, race, relationship with recipient, and family history of disease. Long-term incidence of hypertension, diabetes, cardiovascular disease, and reduced renal function (estimated glomerular filtration rate [eGFR] <30, eGFR <45 mL/min/1.73 m 2 ) were compared between groups using proportional hazards models.

RESULTS

Of 1862 donors with predonation pregnancies, 48 had preeclampsia/eclampsia, 49 had GHtn without preeclampsia, and 43 had GDM. Donors had a long interval between first pregnancy and donation (median, 18.5 y; interquartile range, 10.6-27.5) and a long postdonation follow-up time (median, 18.0; interquartile range, 9.2-27.7 y). GHtn was associated with the development of hypertension (hazard ratio, 1.89; 95% confidence interval, 1.26-2.83); GDM was associated with diabetes (hazard ratio, 3.04; 95% confidence interval, 1.33-6.99). Pregnancy complications were not associated with eGFR <30 or eGFR <45 mL/min/1.73 m 2 .

CONCLUSIONS

Our data suggest that women with predonation pregnancy-related complications have long-term risks even with a normal donor evaluation. Donor candidates with a history of pregnancy-related complications should be counseled about these risks.

Risk Prediction for Delayed Allograft Function: Analysis of the Deterioration of Kidney Allograft Function (DeKAF) Study Data

BACKGROUND

Delayed graft function (DGF) of a kidney transplant results in increased cost and complexity of management. For clinical care or a DGF trial, it would be ideal to accurately predict individual DGF risk and provide preemptive treatment. A calculator developed by Irish et al has been useful for predicting population but not individual risk.

METHODS

We analyzed the Irish calculator (IC) in the DeKAF prospective cohort (incidence of DGF = 20.4%) and investigated potential improvements.

RESULTS

We found that the predictive performance of the calculator in those meeting Irish inclusion criteria was comparable with that reported by Irish et al. For cohorts excluded by Irish: (a) in pump-perfused kidneys, the IC overestimated DGF risk; (b) in simultaneous pancreas kidney transplants, the DGF risk was exceptionally low. For all 3 cohorts, there was considerable overlap in IC scores between those with and those without DGF. Using a modified definition of DGF-excluding those with single dialysis in the first 24 h posttransplant-we found that the calculator had similar performance as with the traditional DGF definition. Studying whether DGF prediction could be improved, we found that recipient cardiovascular disease was strongly associated with DGF even after accounting for IC-predicted risk.

CONCLUSIONS

The IC can be a useful population guide for predicting DGF in the population for which it was intended but has limited scope in expanded populations (SPK, pump) and for individual risk prediction. DGF risk prediction can be improved by inclusion of recipient cardiovascular disease.

Outcomes of Kidney Donors With Impaired Fasting Glucose

BACKGROUND

Many kidney donor candidates with impaired fasting glucose (IFG) and all candidates with diabetes are currently excluded from kidney donation, fearing the development of an accelerated course of diabetic kidney disease in the remaining kidney.

METHODS

We studied mortality, proteinuria, and end-stage kidney disease (ESKD) in 8280 donors who donated between 1963 and 2007 according to donation fasting plasma glucose (FPG): <100 mg/dL (n = 6204), 100-125 mg/dL (n = 1826), and ≥126 mg/dL (n = 250).

RESULTS

Donors with IFG and those with FPG ≥126 mg/dL were older, less likely to be non-Hispanic White, had a higher body mass index, and were more likely to be related to their recipient. After 15.7 ± 10.5 y from donation to study close, 4.4% died, 29.4% developed hypertension, 13.8% developed proteinuria, and 41 (0.5%) developed ESKD. In both the logistic and Cox models, IFG was associated with a higher diabetes risk (adjusted hazard ratio [aHR], 1.65; 95% confidence interval [CI], 1.18-2.30) and hypertension (aHR, 1.35; 95% CI, 1.10-1.65; P = 0.003 for both), but not higher risk of proteinuria or ESKD. The multivariable risk of mortality in donors with ≥126 mg/dL was higher than the 2 other groups, but risks of proteinuria, cardiovascular disease, and reduced estimated glomerular filtration rate were similar to those with FPG <126 mg/dL. Three cases of ESKD developed in the 250 donors with FPG ≥126 mg/dL at 18.6 ± 10.3 y after donation (aHR, 5.36; 95% CI, 1.0-27.01; P = 0.04).

CONCLUSIONS

Donors with IFG and the majority of donors with ≥126 mg/dL do well and perhaps should not be routinely excluded from donation.

Correlation of Glomerular Size With Donor-Recipient Factors and With Response to Injury

BACKGROUND

Glomerular size in renal allografts is impacted by donor-recipient factors and response to injury. In serial biopsies of patients with well-functioning grafts, increased glomerular size correlates with better survival. However, no previous study has addressed the association of glomerular size at the time of a for-cause biopsy and clinical/histopathologic markers of injury, or effect on long-term graft outcome.

METHODS

Two cohorts of kidney transplant recipients enrolled in the Deterioration of Kidney Allograft Function study were evaluated. The prospective cohort (PC, n = 581): patients undergoing first for-cause kidney biopsy 1.7 ± 1.4 (mean ± SD) y posttransplant; and the cross-sectional cohort (CSC, n = 446): patients developing new-onset renal function deterioration 7.7 ± 5.6 y posttransplant. Glomerular planar surface area and diameter were measured on all glomeruli containing a vascular pole. Kidney biopsy was read centrally in a blinded fashion according to the Banff criteria.

RESULTS

Glomerular area was significantly higher in the CSC than the PC; time from transplant to indication biopsy was associated with glomerular area in both cohorts (P values ≤ 0.001). Glomerular area was associated with indices of microvascular inflammation (glomerulitis, peritubular capillary infiltrates; P values ≤ 0.001) and segmental glomerulosclerosis (P value < 0.0001). In the CSC, higher glomerular area was associated with higher estimated glomerular filtration rate (P value ≤ 0.001) and increased graft survival after accounting for microvascular inflammation (adjusted hazard ratio = 0.967; 95% confidence interval: 0.948-0.986; hazard ratio in biopsies without evidence of diabetes or antibody mediated rejection = 0.919, 95% confidence interval: 0.856-0.987).

CONCLUSIONS

Glomerular size is associated with histopathologic features present at the time of indication biopsy and with increased graft survival in the CSC.

Outcomes of Kidney Allograft and Recipient Survival After Liver Transplantation by Induction Type in the United States

There are several choices for induction immunosuppression in kidney-after-liver transplantation. We used the Scientific Registry of Transplant Recipients database. We assessed all kidney-after-liver transplant recipients in the United States between 1/1/2000 and 7/31/2017 to study kidney graft and patient outcomes by induction type. We only included patients discharged on tacrolimus and mycophenolate with or without steroids and had a negative crossmatch before kidney engraftment. We grouped recipients by kidney induction type into the following 3 groups: depletional (n = 550), nondepletional (n = 434), and no antibody induction (n = 144). We studied patient and kidney allograft survival using Cox proportional hazard regression, with transplant center included as a random effect. Models were adjusted for liver induction regimen, recipient and donor age, sex, human leukocyte antigen mismatches, payor type, living donor kidney transplantation, dialysis status, time from liver engraftment, hepatitis C virus status, and the presence of diabetes mellitus at time of kidney transplantation and transplantation year. The 6-month and 1-year rejection rates did not differ between groups. Compared with no induction, neither depletional nor nondepletional induction was associated with an improved recipient or graft survival in the multivariable models. Depletional induction at the time of liver transplantation was associated with worse patient survival after kidney transplantation (hazard ratio [HR], 1.7; 95% confidence interval [CI], 1.09-2.67; P = 0.02). Living donor kidney transplantation was associated with a 48.1% improved graft survival (HR, 0.52; 95% CI, 0.33-0.82; P = 0.00). In conclusion, in the settings of a negative cross-match and maintenance with tacrolimus and mycophenolate, induction use was not associated with a patient or graft survival benefit in kidney-after-liver transplantations.

Intermediate Renal Outcomes, Kidney Failure, and Mortality in Obese Kidney Donors

BACKGROUND

Obesity is associated with the two archetypal kidney disease risk factors: hypertension and diabetes. Concerns that the effects of diabetes and hypertension in obese kidney donors might be magnified in their remaining kidney have led to the exclusion of many obese candidates from kidney donation.

METHODS

We compared mortality, diabetes, hypertension, proteinuria, reduced eGFR and its trajectory, and the development of kidney failure in 8583 kidney donors, according to body mass index (BMI). The study included 6822 individuals with a BMI of <30 kg/m2, 1338 with a BMI of 30-34.9 kg/m2, and 423 with a BMI of ≥35 kg/m2. We used Cox regression models, adjusting for baseline covariates only, and models adjusting for postdonation diabetes, hypertension, and kidney failure as time-varying covariates.

RESULTS

Obese donors were more likely than nonobese donors to develop diabetes, hypertension, and proteinuria. The increase in eGFR in obese versus nonobese donors was significantly higher in the first 10 years (3.5 ml/min per 1.73m2 per year versus 2.4 ml/min per 1.73m2 per year; P<0.001), but comparable thereafter. At a mean±SD follow-up of 19.3±10.3 years after donation, 31 (0.5%) nonobese and 12 (0.7%) obese donors developed ESKD. Of the 12 patients with ESKD in obese donors, 10 occurred in 1445 White donors who were related to the recipient (0.9%). Risk of death in obese donors was not significantly increased compared with nonobese donors.

CONCLUSIONS

Obesity in kidney donors, as in nondonors, is associated with increased risk of developing diabetes and hypertension. The absolute risk of ESKD is small and the risk of death is comparable to that of nonobese donors.

Risk of kidney disease after living kidney donation

Living donor kidney transplantation benefits the recipient. However, kidney failure can occur in a small fraction of donors — the risk is not uniform but varies according to donor characteristics. Studies to date have failed to match on important factors, such as era, environment or family history. Long-term studies with well-matched healthy controls are therefore needed.

Precision Dosing for Tacrolimus Using Genotypes and Clinical Factors in Kidney Transplant Recipients of European Ancestry

Genetic variation in the CYP3A4 and CYP3A5 (CYP3A4/5) genes, which encode the key enzymes in tacrolimus metabolism, is associated with tacrolimus clearance and dose requirements. Tacrolimus has a narrow therapeutic index with high intra- and intersubject variability, in part because of genetic variation. High tacrolimus clearance and low trough concentration are associated with a greater risk for rejection, whereas high troughs are associated with calcineurin-induced toxicity. The objective of this study was to develop a model of tacrolimus clearance with a dosing equation accounting for genotypes and clinical factors in adult kidney transplant recipients of European ancestry that could preemptively guide dosing. Recipients receiving immediate-release tacrolimus for maintenance immunosuppression from 2 multicenter studies were included. Participants in the GEN03 study were used for tacrolimus model development (n = 608 recipients) and was validated by prediction performance in the DeKAF Genomics study (n = 1361 recipients). Nonlinear mixed-effects modeling was used to develop the apparent oral tacrolimus clearance (CL/F) model. CYP3A4/5 genotypes and clinical covariates were tested for their influence on CL/F. The predictive performance of the model was determined by assessing the bias (median prediction error [ME] and median percentage error [MPE]) and the precision (root median squared error [RMSE]) of the model. CYP3A5*3, CYP3A4*22, corticosteroids, calcium channel blocker and antiviral drug use, age, and diabetes significantly contributed to the interindividual variability of oral tacrolimus apparent clearance. The bias (ME, MPE) and precision (RMSE) of the final model was good, 0.49 ng/mL, 6.5%, and 3.09 ng/mL, respectively. Prospective testing of this equation is warranted.

Incidence, risk factors, and long-term outcomes associated with antibody-mediated rejection - The long-term Deterioration of Kidney Allograft Function (DeKAF) prospective cohort study

Major gaps remain in our understanding of antibody-mediated rejection (AMR) after kidney transplant. We examined the incidence, risk factors, response to treatment, and effects on outcomes of AMR at seven transplant programs in the long-term Deterioration of Kidney Allograft Function prospective study cohort. Among 3131 kidney recipients, there were 194 observed AMR cases (6.2%) during (mean ± SD) 4.85 ± 1.86 years of follow-up. Time to AMR was 0.97 ± 1.17 (median, 0.48) years. Risk factors for AMR included younger recipient age, human leukocyte antigen DR mismatches, panel-reactive antibody >0%, positive T- or B-cell cross-match, and delayed graft function. Compared with no AMR, the adjusted time-dependent hazard ratio for death-censored graft failure is 10.1 (95% confidence interval, 6.5-15.7) for all AMR patients, 4.0 (2.5, 9.1) for early AMR (<90 days after transplant), and 24.0 (14.0-41.1) for late AMR (≥90 days after transplant). Patients were treated with different therapeutic combinations. Of 194 kidney transplant recipients with AMR, 50 (25.8%) did not respond to treatment, defined as second AMR within 100 days or no improvement in estimated glomerular filtration rate by 42 days. Long-term outcomes after AMR are poor, regardless of the initial response to treatment. Better prevention and new therapeutic strategies are needed to improve long-term allograft survival.

i-IFTA and chronic active T cell-mediated rejection: A tale of 2 (DeKAF) cohorts

Inflammation in areas of fibrosis (i-IFTA) in posttransplant biopsies is part of the diagnostic criteria for chronic active TCMR (CA TCMR -- i-IFTA ≥ 2, ti ≥ 2, t ≥ 2). We evaluated i-IFTA and CA TCMR in the DeKAF indication biopsy cohorts: prospective (n = 585, mean time to biopsy = 1.7 years); cross-sectional (n = 458, mean time to biopsy = 7.8 years). Grouped by i-IFTA scores, the 3-year postbiopsy DC-GS is similar across cohorts. Although a previous acute rejection episode (AR) was more common in those with i-IFTA on biopsy, the majority of those with i-IFTA had not had previous AR. There was no association between type of previous AR (AMR, TCMR) and presence of i-IFTA. In both cohorts, i-IFTA was associated with markers of both cellular (increased Banff i, t, ti) and humoral (increased g, ptc, C4d, DSA) activity. Biopsies with i-IFTA = 1 and i-IFTA ≥ 2 with concurrent t ≥ 2 and ti ≥ 2 had similar DC-GS. These results suggest that (a) i-IFTA≥1 should be considered a threshold for diagnoses incorporating i-IFTA, ti, and t; (b) given that i-IFTA ≥ 2,t ≥ 2, ti ≥ 2 can occur in the absence of preceding TCMR and that the component histologic scores (i-IFTA,t,ti) each indicate an acute change (albeit i-IFTA on the nonspecific background of IFTA), the diagnostic category "CA TCMR" should be reconsidered.

Pediatric retransplantation of the liver: A prognostic scoring tool

Few prognostic models have been created in children that receive liver retransplantation (rLT). We examined the SRTR database of 731 children that underwent second liver transplant between 2002 and 2018. Proportional hazards models using backward variable selection were used to identify recipient, donor, and surgical characteristics associated with survival. A simple prognostic scoring system or nomogram (ie, each risk factor was weighted on a five-point scale) was constructed based on the fitted model. Recipient age (P < .001), MELD/PELD (P < .001), recipient ventilated (P = .003), donor cause of death (P = .024), graft type (P = .045), first graft loss due to biliary tract complications (P = .048), and survival time of the first graft (P = .006) were significant predictors of retransplant survival. The bias-corrected Harrell's C-index for the multivariable model was 0.63. Survival was significantly different (P < .001) for those at low risk (0-4 points), medium risk (5-7 points), and high risk (8+ points). Survival was equivalent between low risk pediatric second transplant recipients and pediatric primary liver transplant recipients (P = .67) but significantly worse for medium- (P < .001) and high-risk (P < .001) recipients. With simple clinical characteristics, this scoring tool can modestly discriminate between those children at high risk and those children at low risk of poor outcomes after second liver transplant.

Inflammation in areas of fibrosis: The DeKAF prospective cohort

Inflammation in areas of fibrosis (i-IFTA) in posttransplant biopsy specimens has been associated with decreased death-censored graft survival (DC-GS). Additionally, an i-IFTA score ≥ 2 is part of the diagnostic criteria for chronic active TCMR (CA TCMR). We examined the impact of i-IFTA and t-IFTA (tubulitis in areas of atrophy) in the first biopsy for cause after 90 days posttransplant (n = 598); mean (SD) 1.7 ± 1.4 years posttransplant. I-IFTA, present in 196 biopsy specimens, was strongly correlated with t-IFTA, and Banff i. Of the 196, 37 (18.9%) had a previous acute rejection episode; 96 (49%) had concurrent i score = 0. Unlike previous studies, i-IFTA = 1 (vs 0) was associated with worse 3-year DC-GS: (i-IFTA = 0, 81.7%, [95% CI 77.7 to 85.9%]); i-IFTA = 1, 68.1%, [95% CI 59.7 to 77.6%]; i-IFTA = 2, 56.1%, [95% CI 43.2 to 72.8%], i-IFTA = 3, 48.5%, [95% CI 31.8 to 74.0%]). The association of i-IFTA with decreased DC-GS remained significant when adjusted for serum creatinine at the time of the biopsy, Banff i, ci and ct, C4d and DSA. T-IFTA was similarly associated with decreased DC-GS. Of these indication biopsies, those with i-IFTA ≥ 2, without meeting other criteria for CA TCMR had similar postbiopsy DC-GS as those with CA TCMR. Those with i-IFTA = 1 and t ≥ 2, ti ≥ 2 had postbiopsy DC-GS similar to CA TCMR. Biopsies with i-IFTA = 1 had similar survival as CA TCMR when biopsy specimens also met Banff criteria for TCMR and/or AMR. Studies of i-IFTA and t-IFTA in additional cohorts, integrating analyses of Banff scores meeting criteria for other Banff diagnoses, are needed.

Re-hospitalization after pediatric kidney transplant: A single-center study

BACKGROUND

Little data exist on re-hospitalization rates in pediatric kidney recipients (KTx) particularly with the evolution of transplant immunosuppression.

METHODS

In a single-center, retrospective study of pediatric KTx between 2006 and 2016, we assessed re-hospitalization after KTx admission, stratified by whether the re-admit was early (<30 days post-KTx discharge) or late (>30 days), and compared two different immunosuppression eras (one with and one without steroids).

RESULTS

Of 197 KTx, 156 (79%) patients were re-hospitalized in 1st year, 85 (56%) within 30 days of discharge (total 490 1st year re-hospitalizations). Younger age was associated with early and late re-hospitalizations. African American race was associated with early re-hospitalizations. Of the 123 and 74 discharged on steroid-avoidance (maintenance immunosuppression included MMF in 95%; FK in 50%; CSA in 50%) and steroid-inclusive (AZA in 66%; MMF in 34%; FK in 30%; CSA in 70%), re-hospitalization rates, timing post-transplant, length, and number were not significantly different (P .38; .1; .56; .11). Admission diagnoses analysis demonstrated that steroid-avoidance recipients had anemia/leucopenia/thrombocytopenia, significantly more often, as one of their admission diagnoses (16% vs 4%; P < .001) and had a rejection diagnosis significantly less often (6% vs 18%; P < .001). Infection diagnoses were not statistically different between groups. Re-hospitalization, early or late, did not predict worse graft/ patient survival but predicted further hospitalizations.

CONCLUSIONS

Re-hospitalization is common after pediatric transplant discharge and predicts further hospitalization regardless of discharge on or off steroids.

Pharmacogenomics in kidney transplant recipients and potential for integration into practice

WHAT IS KNOWN AND OBJECTIVE

Pharmacogenomic biomarkers are now used in many clinical care settings and represent one of the successes of precision medicine. Genetic variants are associated with pharmacokinetic and pharmacodynamic changes leading to medication adverse effects and changes in clinical response. Actionable pharmacogenomic variants are common in transplant recipients and have implications for medications used in transplant, but yet are not broadly incorporated into practice.

METHODS

From the Clinical Pharmacogenetics Implementation Consortium and Dutch Pharmacogenetics Working Group guidelines, and PharmGKB databases, 12 pharmacogenomic genes with 30 variants were selected and used to create diplotypes and actionable pharmacogenomic phenotypes. A total of 853 kidney allograft recipients who had genomic information available from a genome-wide association study were included.

RESULTS

Each recipient had at least one actionable pharmacogenomic diplotype/phenotype, whereas the majority (58%) had three or four actionable diplotypes/phenotypes and 17.4% had five or more among the 12 genes. The participants carried actionable diplotypes/phenotypes for multiple medications, including tacrolimus, azathioprine, clopidogrel, warfarin, simvastatin, voriconazole, antidepressants and proton-pump inhibitors.

WHAT IS NEW AND CONCLUSION

Pharmacogenomic variants are common in transplant recipients, and transplant recipients receive medications that have actionable variants.

CLINICAL TRIAL

Genomics of Transplantation, clinicaltrials.gov (NCT01714440).

Medication adherence is associated with an increased risk of cancer in kidney transplant recipients: a cohort study

Background

Nonadherence to posttransplant immunosuppressive medication is associated with increased rates of rejection and graft loss, yet it is unknown to what degree ideal adherence is associated with the sequelae of overimmunosuppression. Specifically, we questioned whether excellent adherence increased the posttransplant cancer risk.

Methods

Between August 1998 and August 2006, 195 consenting kidney transplant recipients had electronic monitoring of theirimmunosuppressive medication adherence.

Results

Based on their average quantitative adherence to a single immunosuppressant drug over the first 6 months posttransplant, recipients were grouped into adherence tertiles (highest, >97.9% adherence; middle, 91-97.8%; lowest, <91%). The cumulative incidence of cancer was calculated for patients in each tertile, treating death as a competing risk. The association between adherence and cancer rate was calculated after adjusting for recipient risk factors, using a competing risk proportional hazards model. The median duration of follow-up was 10.1 years. The 10-year estimated cumulative cancer incidence was 59.4% in the most adherent, 36.1% in the middle group and 38.1% in the least adherent group (P = 0.006). Excluding nonmelanocytic skin cancers, cancer incidence remained significantly higher in the highest adherence group (P = 0.002).

Conclusions

These data provide additional support for the need to individualize immunosuppression to minimize both rejection and immunosuppressive drug-related complications including cancer.

Long-term outcomes of pediatric kidney transplant recipients with a pretransplant malignancy

A childhood malignancy can rarely progress to ESRD requiring a KT. To date, few reports describe long-term outcomes of pediatric KT recipients with a pretransplant malignancy. Between 1963 and 2015, 884 pediatric (age: 0-17 years old) recipients received 1055 KTs at our institution. KT outcomes were analyzed in children with a pretransplant malignancy. We identified 14 patients who had a pretransplant malignancy prior to KT; the majority were <10 years old at the time of KT. Ten (71%) patients received their grafts from living donors, the majority of which were related to the recipient. Wilms' tumor was the dominant type of pretransplant malignancy, seen in 50% of patients. The other pretransplant malignancy types were EBV-positive lymphoproliferative disorders, non-EBV-positive lymphoma, leukemia, neuroblastoma, soft-tissue sarcoma, and ovarian cancer. Ten of the 14 patients received chemotherapy as part of their pretransplant malignancy treatment. Graft survival at 1, 3, and 5 years was 93%, 83%, and 72%, respectively. Patient survival at 1, 5, and 10 years was 100%, 91%, and 83%, respectively. Six (40%) patients suffered AR following KT; half of them had their first episode of AR within 1 month of KT. Our single-center experience demonstrates that pediatric KT recipients with a previously treated pretransplant malignancy did not exhibit worse outcomes than other pediatric KT patients.

Rapid discontinuation of prednisone in kidney transplant recipients from at-risk subgroups: an OPTN/SRTR analysis

Although rapid discontinuation of prednisone (RDP) after kidney transplantation has been successful in low-risk recipients, there is concern about RDP use in recipients at increased risk for rejection or recurrent disease. Using SRTR, we compared outcomes for RDP versus maintenance prednisone-treated recipients for all adult 1st and 2nd transplants (n = 169 479) and the following 1st transplant subgroups: African American (AA); highly sensitized; those with a potentially recurrent disease; and pediatric recipients. For all adult 1st LD and DD transplants, RDP was associated with better patient and graft survival. For all LD subgroups, RDP and maintenance prednisone were associated with similar patient, graft, and death-censored (DC) graft survival. For 1st transplant DD subgroups, RDP was associated with better patient survival in AA, those with potentially recurrent disease, and pediatric recipients; graft survival with RDP was better in AAs. For adult 2nd DD transplants, RDP was associated with worse DC-graft survival. Importantly, for all differences, the effect size was small. With the exception of 2nd DD transplants, RDP protocols can be used without decreasing patient or graft survival for subgroups of 1st DD and LD kidney transplant recipients and for 2nd LD transplant recipients, at increased risk of rejection or recurrent disease.

Tacrolimus troughs and genetic determinants of metabolism in kidney transplant recipients: A comparison of four ancestry groups

Tacrolimus trough and dose requirements vary dramatically between individuals of European and African American ancestry. These differences are less well described in other populations. We conducted an observational, prospective, multicenter study from which 2595 kidney transplant recipients of European, African, Native American, and Asian ancestry were studied for tacrolimus trough, doses, and genetic determinants of metabolism. We studied the well-known variants and conducted a CYP3A4/5 gene-wide analysis to identify new variants. Daily doses, and dose-normalized troughs were significantly different between the four groups (P < .001). CYP3A5*3 (rs776746) was associated with higher dose-normalized tacrolimus troughs in all groups but occurred at different allele frequencies and had differing effect sizes. The CYP3A5*6 (rs10264272) and *7 (rs413003343) variants were only present in African Americans. CYP3A4*22 (rs35599367) was not found in any of the Asian ancestry samples. We identified seven suggestive variants in the CYP3A4/5 genes associated with dose-normalized troughs in Native Americans (P = 1.1 × 10^-5 -8.8 × 10^-6 ) and one suggestive variant in Asian Americans (P = 5.6 × 10^-6 ). Tacrolimus daily doses and dose-normalized troughs vary significantly among different ancestry groups. We identified potential new variants important in Asians and Native Americans. Studies with larger populations should be conducted to assess the importance of the identified suggestive variants.

The impact of donor and recipient common clinical and genetic variation on estimated glomerular filtration rate in a European renal transplant population

Genetic variation across the human leukocyte antigen loci is known to influence renal-transplant outcome. However, the impact of genetic variation beyond the human leukocyte antigen loci is less clear. We tested the association of common genetic variation and clinical characteristics, from both the donor and recipient, with posttransplant eGFR at different time-points, out to 5 years posttransplantation. We conducted GWAS meta-analyses across 10 844 donors and recipients from five European ancestry cohorts. We also analyzed the impact of polygenic risk scores (PRS), calculated using genetic variants associated with nontransplant eGFR, on posttransplant eGFR. PRS calculated using the recipient genotype alone, as well as combined donor and recipient genotypes were significantly associated with eGFR at 1-year posttransplant. Thirty-two percent of the variability in eGFR at 1-year posttransplant was explained by our model containing clinical covariates (including weights for death/graft-failure), principal components and combined donor-recipient PRS, with 0.3% contributed by the PRS. No individual genetic variant was significantly associated with eGFR posttransplant in the GWAS. This is the first study to examine PRS, composed of variants that impact kidney function in the general population, in a posttransplant context. Despite PRS being a significant predictor of eGFR posttransplant, the effect size of common genetic factors is limited compared to clinical variables.

Influence of the procurement surgeon on transplanted abdominal organ outcomes: An SRTR analysis to evaluate regional organ procurement collaboration

Single-center studies have demonstrated regional organ procurement collaboration to reduce travel redundancy and improve procurement efficiency. We studied deceased donor kidney, liver, and pancreas transplants performed in the United States between 2002 and 2014 using the Scientific Registry of Transplant Recipients (SRTR). We compared graft failure (GF), death-censored graft failure (DCGF), and patient death (PD) between organs procured by surgeons from the recipient's center (transplant procurement team [TPT]) versus surgeons from a different center (NTPT). Primary nonfunction (PNF) was assessed for liver and kidney and delayed graft function (DGF) for kidney using mixed-effects logistic modeling. There were 64 906 liver (61.6% TPT), 118 152 kidney (26.1% TPT), 10 832 simultaneous pancreas kidney (SPK; 56.6% TPT), and 4378 solitary pancreas (SP; 34.0% TPT) transplants. When compared to NTPT, DCGF for organs procured by TPT was significantly less for liver (adjusted HR: 0.93; 95% CI: 0.88-0.98) and marginally significant for kidney (0.97; 0.93-1.00) and SPK (0.90; 0.82-1.00), and not significant for SP (0.98; 0.86 -1.11). DGF for TPT kidney was significantly lower (adjusted OR 0.91; 0.87-0.95). Albeit modest, our findings demonstrate a difference between locally procured organs and those procured by the implanting team. Elucidating the etiology of these differences will enhance regional organ procurement collaboration.

Kidney donor outcomes ≥ 50 years after donation

Many living kidney donors (LDs) are young at donation; yet there are little data on long-term LD follow-up. We report on 66 LDs who donated ≥50 years ago: 22 (33.3%) are still alive (current age, 78.5 ± 7.25 years); 39 (59%) died (mean age at death, 74.2 ± 12.3 years); and 5 are lost to follow-up (mean age at last contact, 68.7 ± 4.6 years). Those who died were older at donation (P < .001). Causes of death included 12 (30.8% of deaths) cardiovascular diseases, 9 (23.0%) respiratory failures, 5 (12.8%) malignancies and 4 (10.3%) infections, and 9 (23%) were unknown or miscellaneous. Forty-nine living donors (74%) developed hypertension at a mean age of 59.9 ± 14.0 years; 12 (18%) developed diabetes at a mean age of 62 ± 19.4 years; and 11 (16.7%) developed proteinuria at a mean age of 60.6 ± 18.2 years-each at a similar incidence as seen in the age-matched general population. At last follow-up, the eGFR by CKD-EPI (mean ± SD) for donors currently alive was 60.2 ± 13.4 mL/min/1.73 m² ; for those that died, 54.0 ± 21.5 mL/min/1.73 m² ; for those lost to follow-up, 55.6 ± 7.5 mL/min/1.73 m² . ESRD developed in 2 (3.3%). SF-36 quality of life health survey scores (n = 21) were similar to the age-matched general population.

Larger nephron size, low nephron number, and nephrosclerosis on biopsy as predictors of kidney function after donating a kidney

It is unclear whether structural findings in the kidneys of living kidney donors predict postdonation kidney function. We studied living kidney donors who had a kidney biopsy during donation. Nephron size was measured by glomerular volume, cortex volume per glomerulus, and mean cross-sectional tubular area. Age-specific thresholds were defined for low nephron number (calculated from CT and biopsy measures) and nephrosclerosis (global glomerulosclerosis, interstitial fibrosis/tubular atrophy, and arteriosclerosis). These structural measures were assessed as predictors of postdonation measured GFR, 24-hour urine albumin, and hypertension. Analyses were adjusted for baseline age, gender, body mass index, systolic and diastolic blood pressure, hypertension, measured GFR, urine albumin, living related donor status, and time since donation. Of 2673 donors, 1334 returned for a follow-up visit at a median 4.4 months after donation, with measured GFR <60 mL/min/1.73 m² in 34%, urine albumin >5 mg/24 h in 13%, and hypertension in 5.3%. Larger glomerular volume and interstitial fibrosis/tubular atrophy predicted follow-up measured GFR <60 mL/min/1.73 m² . Larger cortex volume per glomerulus and low nephron number predicted follow-up urine albumin >5 mg/24 h. Arteriosclerosis predicted hypertension. Microstructural findings predict GFR <60 mL/min/1.73 m² , modest increases in urine albumin, and hypertension shortly after kidney donation.

Long-term follow-up of the DeKAF cross-sectional cohort study

The DeKAF study was developed to better understand the causes of late allograft loss. Preliminary findings from the DeKAF cross-sectional cohort (with follow-up < 20 months) have been published. Herein, we present long-term outcomes in those recipients (mean follow-up ± SD, 6.6 ± 0.7 years). Eligibility included being transplanted prior to October 1, 2005; serum creatinine ≤ 2.0 mg/dL on January 1, 2006; and subsequently developing new-onset graft dysfunction leading to a biopsy. Mean time from transplant to biopsy was 7.5 ± 6.1 years. Histologic findings and DSA were studied in relation to postbiopsy outcomes. Long-term follow-up confirms and expands the preliminary results of each of 3 studies: (1) increasing inflammation in area of atrophy (irrespective of inflammation in nonscarred areas [Banff i]) was associated with increasingly worse postbiopsy death-censored graft survival; (2) hierarchical analysis based on Banff scores defined clusters (entities) that differed in long-term death-censored graft survival; and (3) C4d-/DSA- recipients had significantly better (and C4d+/DSA+ worse) death-censored graft survival than other groups. C4d+/DSA- and C4d-/DSA+ had similar intermediate death-censored graft survival. Clinical and histologic findings at the time of new-onset graft dysfunction define high- vs low-risk groups for long-term death-censored graft survival, even years posttransplant. These findings can help differentiate groups for potential intervention studies.

Long-term psychosocial outcomes after nondirected donation: A single-center experience

Short-term studies have demonstrated that nondirected donors (NDDs) have psychosocial outcomes that are similar to donors who donate directly, but long-term studies have not been done. NDDs at our center were surveyed regarding motivation; support during donation; stress related to donation; regret; financial resources used for donation; preferences about communication with the recipient; and cost reimbursement. Of 100 NDDs who donated at our center in the last 20 years, 95 remain in contact with us, and 77 responded to our survey (mean ± standard deviation [SD] 6.7 ± 4 years postdonation). The most common motivation for donation was the desire to help another (99%). Many NDDs received support from family, friends, and employers. NDDs voiced stress about the possibility of recipient kidney rejection, physical consequences to themselves, and financial burden. Only one donor expressed regret. Almost half wanted some recipient information at donation; 61% preferred routine recipient status updates; 56% believed meeting the recipient should occur at any mutually agreeable time; and 55% endorsed reimbursement for expenses. Stressors for NDDs are analogous to those of directed donors; NDDs prefer having some information about the recipient and prefer to be given a choice regarding the timing for communication with the recipient. NDDs supported donation being financially neutral.

How patients choose kidney transplant centers: A qualitative study of patient experiences

Little is known about how patients make the critical decision of choosing a transplant center. In the United States, acceptance criteria, waiting times, and mortality vary significantly by geography and center. We sought to understand patients' experiences and perspectives when selecting transplant centers. We included 82 kidney transplant patients in 20 semi-structured interviews, nine focus groups with local candidates, and three focus groups with national recipients. Sites included two local transplant centers in Minneapolis, Minnesota, and national recipients from across the United States. Transcripts were analyzed by two researchers using a thematic analysis. Several themes emerged related to priorities and barriers when choosing a center. Patients were often unfamiliar with options, even with multiple local centers. Patients described being referred to a specific center by a trusted provider. Patients prioritized perceived reputation, comfort, and convenience. Insurance coverage was both a source of information and a barrier to options. Patients underestimated differences across centers and the effects on being waitlisted and receiving a transplant. Barriers in decision making included an overwhelming scope of information and difficulty locating information relevant to patients with unique medical needs. Informed decisions could be improved by the dissemination of understandable information better tailored to individual patient needs.

Retransplant Outcomes Compared With First Kidney Transplants: Important Observations Not Reported in the Scientific Registry of Transplant Recipients Annual Report

OBJECTIVES

Twice per year, the Scientific Registry of Transplant Recipients provides risk-adjusted center-specific reports of 1- and 3-year outcomes. In addition, the Registry reports 10-year aggregate survival outcomes for kidney transplant recipients. However, in this annual report, no distinction is made between outcomes of patients with a first transplant versus those with retransplants.

MATERIALS AND METHODS

We analyzed data from the Scientific Registry of Transplant Recipients between 1992 and 2015 to determine outcomes after a 1st, 2nd, or ≥ 3rd kidney transplant. Recipients were stratified by donor source (living vs deceased) and transplant number, and rates of graft failure, death-censored graft failure, and death with functioning graft were determined.

RESULTS

From 1992 to 2015, rates of graft failure and death-censored graft failure at 6 months, 1 year, 3 years, 5 years, and 10 years decreased; however, long-term rates of death with functioning graft were unchanged. Outcomes for 1st and 2nd kidney transplant were better than outcomes for ≥ 3rd transplant.

CONCLUSIONS

It would be extremely valuable if the Scientific Registry of Transplant Recipients could present stratified analyses that would account for a host of factors, including organ sequence, which tend to vary by center. The presentation of risk-adjusted outcomes in the annual Registry report could include a more comprehensive assessment of program performance. Such information would be extremely useful for transplant centers, patients, and their support networks, organ procurement organizations, and other transplant stakeholders.