Preemptive Kidney Transplantation Research Articles

#1922 Patterns and 2-year outcomes of preemptive vascular access creation in France

Abstract Background and Aims Most studies on clinical practices regarding the type and the timing of vascular access creation are limited to patients on kidney replacement therapy (KRT) from North American settings. Our aim was to describe patterns of preemptive vascular access creation in patients under nephrology care in France, and to assess the subsequent risks of hemodialysis (HD) initiation with arteriovenous (AV) access use, HD initiation with central venous catheter (CVC) use, initiation of other KRT modality, and competing death. Method From 2013 through 2016, the CKD-REIN cohort included 3033 adult patients with CKD stages 3 to 5 from 40 outpatient nephrology clinics in France, nationally representative geographically and in terms of facility legal status (public, private not for profit, and private for profit). Participants were followed for 5 years or until initiation of kidney replacement therapy (KRT) or death, whichever came first. Patients who underwent a first vascular access creation during follow-up were eligible for this analysis. We described the type, anatomical site and timing of the first vascular access created, as well as patients’ associated characteristics. The number and type of subsequent accesses were also described. Among patients who underwent AV fistula creation first, we used the cumulative incidence functions to estimate the 2-year probabilities of HD initiation with AV access use (independently of its type or order), HD initiation with CVC use, initiation of other KRT modality, and death. Results Over a median follow-up of 5.0 years (interquartile range [IQR], 4.6 to 5.2), 535 patients (18% of the total population) underwent a first vascular access creation. 408 patients (75%) had an AV fistula as their first vascular access, 7 patients (1%), an AV graft, and 127 patients (24%), a CVC. AV fistulas were predominantly located in the lower arm (76%). The median eGFR levels at access creation were 13 (IQR, 10 to 16), 12 (10 to 14) and 9 (6 to 13) ml/min/1.73 m2 for AV fistula, AV graft, and CVC, respectively. Groups defined by their first vascular access did not differ with regards to diabetes status, but patients who received AV fistula as their first vascular access stood out for being younger and having less cardiovascular comorbidities than their counterparts who received AV graft or CVC (Table 1). In contrast to the 7 patients with first AV graft who did not have any subsequent access creation, 22% of those with first AV fistula had at least one subsequent access creation before initiating KRT. The subsequent access was a fistula in 49% of cases (54% of them in the lower arm), a CVC in 48% and a graft in 2%. The 2-year cumulative incidences of HD initiation with AV access use, HD initiation with CVC use, preemptive kidney transplantation and pre-KRT death were 61%, 14%, 2% and 5%, respectively (Fig. 1); 18% of patients undergoing a first AV fistula creation did not experience any event within two years, and 25% did not start HD. No patients received peritoneal dialysis as other KRT modality. Conclusion In this nationwide description of patterns of preemptive vascular access creation, we highlight that lower arm AV fistula is largely prioritized, even after a first failed AV fistula creation. This may contribute to the higher use of AV fistula among HD patients in France compared to North American countries. Most patients who undergo a first AV fistula creation eventually start hemodialysis with an AV access within 2 years of this creation, but 1 out of 4 do not start HD at all (because of death, preemptive transplantation, or stable kidney function). Novel tools assisting clinical decision making in preemptive AV fistula creation are needed.

#2968 Preemptive kidney transplantation: the best option for retransplantation?

Abstract Background and Aims Kidney re-transplantation (Re-KT) is associated with worse outcomes. Better results have been described when the KT is performed preemptive, before the patient returns to dialysis. However, the experience is limited so far. Method We performed a retrospective analysis of KT patients who received a preemptive KT (pRe-KT) in Andalusia between 1978-2023. A case-control study was carried out, choosing 2 controls for each case, adjusted for donor and recipient demographic characteristics (1 patient receiving a second non-preemptive KT [npRe-KT] and 1 patient receiving a first KT). We compared clinical characteristics and evolution between the 3 groups. Results During this period, 12217 KT recipients were registered in Andalusia. Of these, 1380 (11.3%) received at least a second KT. Eighty-two (0.059%) patients were pRe-KT recipients, all of them with a second KT. In the npRe-KT patients, there was a lower proportion of living donors than in the other groups (pRe-KT 30.4%, npRe-KT 6.3%, first KT 28.4%; p < 0.001). There were no differences nor in age neither in gender of donors and recipients. Graft survival in pRe-KT and first KT patients was similar and significantly better than in npRe-KT. Adjusting for donor type (living/deceased), npRe-KT remained as a risk factor. However, we observed no differences in patient survival between groups. Conclusion In pRe-KT patients, outcomes are significantly better than npRe-KT outcomes and similar to that of the first KT. These patients, when their clinical situation allows it, should be evaluated for inclusion on the waiting list before the definitive graft loss. Living donor KT should be actively encouraged in patients who are losing the functionality of their renal graft.

#364 Patient characteristics, treatment history and prognosis of adult survivors of childhood kidney replacement therapy—an ERA Registry study

Abstract Background and Aims Young adults who initiated kidney replacement therapy (KRT) during childhood and reached their 18th birthday (i.e. adult survivors of childhood KRT) are a particularly challenging patient group. Besides the changes associated with adolescence, they go through a transition from paediatric to adult nephrology centres, in which patients are expected to take responsibility of their own care. This increases the risk of non-compliance to treatment and graft failure. Nevertheless, not many epidemiological studies have focused on adult survivors of childhood KRT. This type of study would support healthcare providers in obtaining knowledge about the prognosis of this patient group and, perhaps, recognizing possibilities of treatment improvements. We aimed to provide up-to-date information on patient characteristics, treatment history, (graft) survival, 5-year prognosis and expected remaining lifetime of adult survivors of childhood KRT. Method KRT data was used from 21 European countries/regions that contributed with individual patient data to the European Renal Association (ERA) Registry. Adult survivors of childhood KRT, reaching the age of 18 years between 2008 and 2019, were included in the analysis, and their patient characteristics and treatment trajectories were examined. Kaplan-Meier and Cox proportional hazards regression were used in patient and graft survival analyses. The expected remaining lifetime of all KRT patients from the age of 18 years onwards was calculated overall and stratified by sex and treatment modality at the 18th birthday. Results We included 2 944 patients in the analysis, most of them were 10-14 (32.9%) or 15-17 (30.6%) years at start of KRT, and congenital anomalies of the kidney and urinary tract (CAKUT) were the most frequent cause of kidney failure (38.8%). Peritoneal dialysis was the most common treatment at start of KRT (37.8%), yet the percentage of adult survivors who received a pre-emptive kidney transplant increased from 25.6% in 2008-2011 to 32.4% in 2016-2019. By their 18th birthday, 81.4% of patients had a functioning kidney transplant. The overall unadjusted 5-year patient survival after their 18th birthday was 96.9% (95% CI 96.2-97.5), yet adult survivors on dialysis had an almost 4 times higher risk of death than their peers with a functioning kidney graft (adjusted HR 3.76 (95% CI: 2.55-5.53)). Besides, about 21% of the grafts failed during the 5 years after the 18th birthday (unadjusted 5-year graft survival: 78.9% (95% CI: 77.1-80.7)). Eighteen-year-old kidney transplant recipients reached 74% of the expected remaining lifetime of the general population, whereas dialysis patients only reached 37%. Conclusion Even at the young age of 18 years the remaining life expectancy of kidney transplant recipients was lower compared with the general population, and about one fifth of the grafts failed within 5 years after the patients’ 18th birthday. Still, as expected, adult survivors with a functioning kidney transplant at 18 years showed better outcomes than the ones on dialysis, with a greater 5-year survival and longer life expectancy. This epidemiological study reports on one of the biggest cohorts of adult survivors of childhood KRT studied to date. It provides unique knowledge on the prognosis of these patients, establishing the first step towards the optimization of care in this challenging patient group.

Time trends in preemptive kidney transplantation in Europe: an era registry study.

Preemptive kidney transplantation has better outcomes when compared to transplantation after dialysis. We aimed to examine trends in preemptive kidney transplantation between 2000 and 2019 in Europe and to provide an overview of associated policies, barriers and initiatives. Adult patients from 12 European countries who received a preemptive kidney transplant were included. The representatives of the registries providing these data were questioned on the policies, barriers and initiatives around preemptive kidney transplantation. Between 2000 and 2019, 20251 adults underwent preemptive kidney transplantation (11169 from living donors, 8937 from deceased donors). The proportion of first kidney transplantations that were preemptive more than doubled from 7% in 2000 to 18% in 2019, reflecting a similar relative increase for living donor kidney recipients (from 21% to 43%) and deceased donor kidney recipients (from 4% to 11%). Large international differences were found. The increase in preemptive kidney transplantation was observed across all age, sex and primary renal disease groups. Countries had similar criteria for preemptive waitlisting. Barriers mentioned included donor shortage, late referral to the transplant center and long donor or recipient work-up. Suggested initiatives included raising awareness on the possibility of preemptive kidney transplantation, earlier start and shorter work-up time for recipient and living donor. Over the last two decades the proportion of patients receiving a first kidney transplant preemptively has more than doubled, reflecting a similar relative increase for living and deceased donor kidney recipients.

Outcomes of Combined Liver-Kidney Transplantation – Single Center Experience

There is continuous growth of combined liver-kidney transplantation (CLKTx) numbers with remarkable outcomes, especially among patient with liver cirrhosis and end-stage renal disease. The aim was to present a single center experience. Twenty patients (9 males) with a mean age of 48 (range: 20-62) years underwent CLKTx from 2005 to 2022. Indications were polycystic liver and kidney diseases (ADPKD) in 12 cases, cirrhosis due to hepatitis (4 patients), and 1 case of amyloidosis, alcoholic liver disease, nonalcoholic steatosis, and congenital hepatic fibrosis with concomitant glomerulonephritis. After hepatectomy, half of the patients had orthotopic liver transplantation with piggy-back technique, and the other had conventional technique. All but 1 recipient had biliary end-to-end anastomosis. 3 patients had preemptive kidney graft transplantation. 4 underwent simultaneous right-side nephrectomy due to volume of the right kidney. Kidney was transplanted from the separate incision after abdominal closure with typical anastomoses. Tacrolimus, mycophenolate mofetile, basiliximab, and steroids were applied for all recipients. Mean follow-up was 57.7 ± 54 months. No primary non-function of the grafts occurred. Delayed kidney graft function (DGF) occurred in 8 patients. Three-month, 1-year, and 5-year cumulative survival rates were: 90%, 80%, and 72% respectively. None of the patients required retransplantation, and 1 recipient returned to hemodialysis 19 months after transplantation. Preemptive kidney transplantation and simultaneous right-side nephrectomy were not significant for DGF and recipient survival. No deaths within the first year occurred in piggy-back technique. CLKTx is safe and effective in the treatment of both liver and kidney failure.

Expanding the access to kidney transplantation: Strategies for kidney transplant programs.

Kidney transplantation is the most successful kidney replacement therapy available, resulting in improved recipient survival and societal cost savings. Yet, nearly 70 years after the first successful kidney transplant, there are still numerous barriers and untapped opportunities that constrain the access to transplant. The literature describing these barriers is extensive, but the practices and processes to solve them are less clear. Solutions must be multidisciplinary and be the product of strong partnerships among patients, their networks, health care providers, and transplant programs. Transparency in the referral, evaluation, and listing process as well as organ selection are paramount to build such partnerships. Providing early culturally congruent and patient-centered education as well as maximizing the use of local resources to facilitate the transplant work up should be prioritized. Every opportunity to facilitate pre-emptive kidney transplantation and living donation must be taken. Promoting the use of telemedicine and kidney paired donation as standards of care can positively impact the work up completion and maximize the chances of a living donor kidney transplant.

Long-term Effects of Kidney Transplantation Compared With Dialysis on Intima-media Thickness in Children-Results From the 4C-T Study.

Children requiring kidney replacement therapy experience high burden of cardiovascular (CV) disease leading to increased mortality. Intima-media thickness (IMT) indicating atherosclerosis is a validated surrogate marker for future CV events. We investigated the effect of different treatment modalities (dialysis, preemptive kidney transplantation (KTx), late KTx after dialysis) on IMT by multivariable linear mixed-effect modeling. Patients were enrolled in a prospective cohort study. A total of 261 analyzed children had a mean follow-up of 3 y. Children after preemptive and late KTx had lower levels of IMT when compared with dialysis. Using an interaction term, a significant progression of IMT over time was seen during dialysis (β = 0.0053 mm/y, P = 0.004). IMT before the start of therapy was the most influential determinant in all models. Low IMT was associated with maintenance steroid treatment after preemptive KTx. High IMT on dialysis was associated with higher systolic blood pressure, lower body mass index, lower serum albumin, and lower bicarbonate. IMT remained rather stable in children several years after KTx. In contrast, children on dialysis had higher IMT values, which increased over time. In these children, blood pressure control, calorie and protein intake, and acid-base homeostasis seem important. Taken together, children might profit from early transplantation to limit accumulation of CV risk.

Equity in Preemptive Kidney Transplantation: The Case for Caution.

Equity in Preemptive Kidney Transplantation: The Case for Caution.

Improving pre-emptive access to the kidney transplant waiting list between 2017 and 2021: assessment of a regional program in Aquitaine

Pre-emptive access to the kidney transplant (KT) waiting list remains limited in France, with only 3.9% of patients on pre-emptive KT and 5.6% of patients registered at the time of initiation of dialysis. A similar trend was observed in Aquitaine. The aim of this study was to assess the impact of a regional program in terms of access to the waiting list for patients initiating a kidney replacement therapy (KRT). We included all patients assessed for registration on the list between 2017 and 2020, 2017 being the reference year and 2018 the beginning of the program. Using the CRISTAL and REIN registries, we assessed changes in the number of patients on the list at the time of initiation of dialysis or transplantation. The number of new assessed candidates increased gradually each year from 255 in 2017 to 352 in 2020 (+38%). The number of patients on the list sharply increased in 2018 from 229 in 2017 to 319 in 2018 (+39.3%) and then remained stable. At the initiation of KRT, the proportion of patients registered on the waiting list increased gradually from 7.1% in 2017 to 18.2% in 2020. The proportion of pre-emptive KT remained stable between 2017 and 2021 (around 7%) with a decrease in 2020 (4.6%). Approximately 60% of patients had a contraindication to transplantation throughout the study. This study showed that a regional program aimed at providing better information to healthcare professionals and patients and encouraging rapid assessment of transplant candidates could increase the rate of pre-emptive registration on the KT waiting list for eligible patients over 4 years.

507 Comparison of Healthcare Costs Among Preemptive Kidney Transplant vs Dialysis Patients with Medicare Advantage

507 Comparison of Healthcare Costs Among Preemptive Kidney Transplant vs Dialysis Patients with Medicare Advantage

Implementation of a One-Day Living Kidney Donor Assessment Clinic to Improve the Efficiency of the Living Kidney Donor Evaluation: Program Report.

A key barrier to becoming a living kidney donor is an inefficient evaluation process, requiring more than 30 tests (eg, laboratory and diagnostic tests), questionnaires, and specialist consultations. Donor candidates make several trips to hospitals and clinics, and often spend months waiting for appointments and test results. The median evaluation time for a donor candidate in Ontario, Canada, is nearly 1 year. Longer wait times are associated with poorer outcomes for the kidney transplant recipient and higher health care costs. A shorter, more efficient donor evaluation process may help more patients with kidney failure receive a transplant, including a pre-emptive kidney transplant (ie, avoiding the need for dialysis). In this report, we describe the development of a quality improvement intervention to improve the efficiency, effectiveness, and patient-centeredness of the donor candidate evaluation process. We developed a One-Day Living Kidney Donor Assessment Clinic, a condensed clinic where interested donor candidates complete all testing and consultations within 1 day. The One-Day Living Kidney Donor Assessment Clinic was developed after performing a comprehensive review of the literature, receiving feedback from patients who have successfully donated, and meetings with transplant program leadership from St. Joseph's Healthcare Hamilton. A multistakeholder team was formed that included health care staff from nephrology, transplant surgery, radiology, cardiology, social work, nuclear medicine, and patients with the prior lived experience of kidney donation. In the planning stages, the team met regularly to determine the objectives of the clinic, criteria for participation, clinic schedule, patient flow, and clinic metrics. Donor candidates entered the One-Day Clinic if they completed initial laboratory testing and agreed to an expedited process. If additional testing was required, it was completed on a different day. Donor candidates were reviewed by the nephrologist, transplant surgeon, and donor coordinator approximately 2 weeks after the clinic for final approval. The team continues to meet regularly to review donor feedback, discuss challenges, and brainstorm solutions. The One-Day Clinic was implemented in March 2019, and has now been running for 4 years, making iterative improvements through continuous patient and provider feedback. To date, we have evaluated more than 150 donor candidates in this clinic. Feedback from donors has been uniformly positive (98% of donors stated they were very satisfied with the clinic), with most noting that the clinic was efficient and minimally impacted work and family obligations. Hospital leadership, including the health care professionals from each participating department, continue to show support and collaborate to create a seamless experience for donor candidates attending the One-Day Clinic. Clinic spots are limited, meaning some interested donor candidates may not be able to enter a One-Day Clinic the same month they come forward. This patient-centered quality improvement intervention is designed to improve the efficiency and experience of the living kidney donor evaluation, result in better outcomes for kidney transplant recipients, and potentially increase living donation. Our next step is to conduct a formal evaluation of the clinic, measuring qualitative feedback from health care professionals working in the clinic and donor candidates attending the clinic, and measuring key process and outcome measures in donor candidates who completed the one-day assessment compared with those who underwent the usual care assessment. This program evaluation will provide reliable, regionally relevant evidence that will inform transplant centers across the country as they consider incorporating a similar one-day assessment model.

Changes in vascular access profile for pediatric hemodialysis patients over time: A registry-based study from Catalonia.

The criteria for vascular access (VA) selection in pediatric hemodialysis (HD) population has changed over time until the current patient-centered approach using the individualized Life-Plan. We analyzed the type of VA used by incident and prevalent end-stage kidney disease (ESKD) pediatric patients (pts) treated with HD in Catalonia. Data from the Catalan Renal Registry of ESKD pts under 18 years of age undergoing kidney replacement therapy (KRT) were examined for a 22-year period (1997-2018). ESKD children starting KRT through HD decreased progressively from 55.6% (1997-2001) to 38.2% (2012-2018) and, conversely, there was an increase in pts starting KRT by preemptive kidney transplantation (KT) from 28.9% to 42.6% between the same periods (for both comparisons, p = 0.007). Most ESKD pts started HD by fistula (AVF) from 1997 to 2001 (56.5%) but this percentage decreased over time and no AVFs were used to start HD in children from 2012 to 2018. Likewise, the percentage of children starting HD by tunneled catheter increased progressively from 8.7% to 72.2% between the same periods (for both comparisons, p < 0.001). Regarding prevalent ESKD pts, children on HD decreased from 34.9% in 1997 to 4.7% in 2018 and, conversely, pts with a functioning kidney graft increased from 62.8% to 92.4% during the same periods (for both comparisons, p < 0.001). There was a progressive decrease in the percentage of children dialyzed by AVF from 100% in 1997 to 0% in 2018 (p < 0.001). The KT rate increased from 5.4 per million population (pmp) in 1997 to 17.1 pmp in 2018 (p = 0.007). The median time on HD prior to the first KT progressively decreased to 6.6 months (2014-2018). The high KT rate was a determining factor in choosing the VA type in the incident and prevalent pediatric population treated with HD in Catalonia.

Preemptive kidney transplantation: why, when, and how?

Among renal replacement therapies, preemptive kidney transplantation (PKT) presents the best clinical, social, and economic results. However, it is still infrequently chosen as first therapy for patients with irreversible kidney failure. Initiatives in different parts of the world were developed to identify the reasons why PKT is still not widely used and to facilitate the access of patients with end-stage kidney disease to the advantages associated with it. This article addresses the main advantages and difficulties of PKT and discusses when it should be indicated and how to prepare potential recipients for PKT.

Factors to consider during anesthesia in patients undergoing preemptive kidney transplantation: a propensity-score matched analysis

BackgroundInternational guidelines have recommended preemptive kidney transplantation (KT) as the preferred approach, advocating for transplantation before the initiation of dialysis. This approach is advantageous for graft and patient survival by avoiding dialysis-related complications. However, recipients of preemptive KT may undergo anesthesia without the opportunity to optimize volume status or correct metabolic disturbances associated with end-stage renal disease. In these regard, we aimed to investigate the anesthetic events that occur more frequently during preemptive KT compared to nonpreemptive KT.MethodsThis is a single-center retrospective study. Of the 672 patients who underwent Living donor KT (LDKT), 388 of 519 who underwent nonpreemptive KT were matched with 153 of 153 who underwent preemptive KT using propensity score based on preoperative covariates. The primary outcome was intraoperative hypotension defined as area under the threshold (AUT), with a threshold set at a mean arterial blood pressure below 70 mmHg. The secondary outcomes were intraoperative metabolic acidosis estimated by base excess and serum bicarbonate, electrolyte imbalance, the use of inotropes or vasopressors, intraoperative transfusion, immediate graft function evaluated by the nadir creatinine, and re-operation due to bleeding.ResultsAfter propensity score matching, we analyzed 388 and 153 patients in non-preemptive and preemptive groups. The multivariable analysis revealed the AUT of the preemptive group to be significantly greater than that of the nonpreemptive group (mean ± standard deviation, 29.7 ± 61.5 and 14.5 ± 37.7, respectively, P = 0.007). Metabolic acidosis was more severe in the preemptive group compared to the nonpreemptive group. The differences in the nadir creatinine value and times to nadir creatinine were statistically significant, but clinically insignificant.ConclusionIntraoperative hypotension and metabolic acidosis occurred more frequently in the preemptive group during LDKT. These findings highlight the need for anesthesiologists to be prepared and vigilant in managing these events during surgery.

Persistent hyperparathyroidism after preemptive kidney transplantation

BackgroundLong-term dialysis vintage is a predictor of persistent hyperparathyroidism (HPT) after kidney transplantation (KTx). Recently, preemptive kidney transplantation (PKT) has increased. However, the incidence, predictors, and clinical implications of HPT after PKT are unclear. Here, we aimed to elucidate these considerations.MethodsIn this retrospective cohort study, we enrolled patients who underwent PKT between 2000 and 2016. Those who lost their graft within 1 year posttransplant were excluded. HPT was defined as an intact parathyroid hormone (PTH) level exceeding 80 pg/mL or hypercalcemia unexplained by causes other than HPT. Patients were divided into two groups based on the presence of HPT 1 year after PKT. The primary outcome was the predictors of HPT after PKT, and the secondary outcome was graft survival.ResultsAmong the 340 consecutive patients who underwent PKT, 188 did not have HPT (HPT-free group) and 152 had HPT (HPT group). Multivariate logistic regression analysis revealed that pretransplant PTH level (P < 0.001; odds ratio [OR], 5.480; 95% confidence interval [CI], 2.070–14.50) and preoperative donor-estimated glomerular filtration rate (P = 0.033; OR, 0.978; 95% CI, 0.957–0.998) were independent predictors of HPT after PKT. Death-censored graft survival was significantly lower in the HPT group than that in the HPT-free group (90.4% vs. 96.4% at 10 years, P = 0.009).ConclusionsPretransplant PTH levels and donor kidney function were independent predictors of HPT after PKT. In addition, HPT was associated with worse graft outcomes even after PKT.

#6858 GRAFT SURVIVAL IN MULTIPLE KIDNEY TRANSPLANT RECIPIENTS FROM CHILDHOOD TO ADULTHOOD: AN ERA STUDY FROM 1978 UNTIL 2019

Abstract Background and Aims Knowledge regarding graft survival after transplantation in European children with multiple kidney transplants followed from childhood into adulthood including factors affecting these outcomes is lacking. Method Using ERA Registry data, we investigated all patients on kidney replacement therapy (KRT) who received their first kidney transplant (KT) before 20 years of age between 1978 and 2019. Graft survival after first, second and third KT were studied alongside their risk factors, using Kaplan-Meier survival analysis and multivariable Cox regression models. Results Among 10012 paediatric KT candidates, 8601, 1962 and 412 received at least one, two and three KTs. Graft survival at 5 and 10 years was 80.6% and 65.7% for first KTs, 71.3% and 53.7% for second KTs and 67.1 and 49.5% for third KTs. Factors associated with increased graft failure risk were having glomerulonephritis or a recurrent disease as cause of kidney failure for first KT recipients (aHR 1.24, 95%CI 1.12-1.37 and aHR 1.24, 95%CI 1.13-1.37, respectively). Patients whose first KT lifespan was between 0–30 days or more than 5 years presented lower graft failure risks regarding their second KT compared to patients whose KT survived between 1–5 years (aHR 0.79, 95%CI 0.64-0.98 and aHR 0.73, 95%CI 0.61-0.88, respectively). Similar results were found for third KT recipients whose second KT lived for more than 5 years (aHR 0.61, 95%CI 0.41-0.92). Patients who were transplanted for the first and second time before 2007 presented a higher graft failure risk compared to patients who received their KT between 2016–2019 (aHR 2.09, 95%CI 1.65-2.65 and aHR 1.63 95%CI 1.29-2.06 for the transplantation era before 2000 and between 2000–2007 concerning the first KT; and aHR 1.69, 95%CI 1.15-2.47 and aHR 1.51, 95%CI 1.06-2.16, respectively for the era before 2000 and between 2000–2007 concerning the second KT). Pre-emptive KTs presented less graft failure compared to patients who received dialysis &amp;gt; 1 year for first and second KT (aHR 0.89, 95%CI 0.81-0.98 and aHR 0.63, 95%CI 0.51-0.78,respectively). Patients having received a LD KT had less chances for graft failure for first and second KT (aHR 0.77, 95%CI 0.7-0.84 and aHR 0.71 (0.6-0.85, respectively). Having a second LD KT (no matter the donor type for first KT) was advantageous compared to having a second DD. Conclusion Graft outcomes after pediatric kidney (re)transplantation have improved significantly over time for all recipient subgroups, especially for patients with LD KT, longer previous KT lifespan and pre-emptive KT. Patients with GN and recurrent diseases as causes of their kidney failure showed the poorest outcomes, highlighting the need for continued progress in this field.

#5059 EXTERNAL VALIDATION OF THE KFRE AND GRAMS PREDICTION MODELS FOR DEATH AND KRT IN A SPANISH POPULATION WITH ADVANCED CHRONIC KIDNEY DISEASE

Abstract Background and Aims The Kidney Failure Risk Equation (KFRE) is used to predict the risk of kidney replacement therapy (KRT) initiation in the following 2 and 5 years, in patients with chronic kidney disease (CKD) stages G3-G5. The Grams model is applied exclusively to stage G4-G5 patients who have a higher risk of dying or requiring KRT. This model predicts both events, KRT and death, at 2 and 4 years, but unlike the KFRE, it considers the patient's death as a competing event with respect to the start of RRT. It has been suggested that the Grams model makes a more accurate prediction of the onset of KRT in the long term, since by including mortality as a competing event it does not overestimate the risk of KRT. However, there are few external validations of the Grams model to predict mortality in patients with CKD G4+. We performed an external validation of both models with respect to the start of KRT and mortality in a Spanish population with CKD G4+, followed up prospectively during 4-9 years. Method We conducted a prospective cohort analysis of incident patients followed in the Advanced Chronic Kidney Disease clinic of the Hospital Universitario Fundación Alcorcón, Spain between 1-1-2014 and 31-12-2018 who had CKD G4-G5. Clinical data was registered prospectively in a database at each visit to the clinic. Follow-up ended on 31-12-2022. For each patient, the follow-up time ranged from 4 to 9 years. The outcomes were: observed incidence of KRT (haemodialysis, peritoneal dialysis, or pre-emptive kidney transplantation) by 2, 4 and 5 years and death at 2 and 4 years before starting KRT. The predictors used in the study were calculated at the time of initial clinic referral and included the 2-year and 4-year Grams’ calculator risk scores (Grams-2 and Grams-4, respectively) for KRT and death and the 2-year and 5-year 4-variable KFRE scores for KRT (KFRE-2 and KFRE-5 respectively). We performed calibration and discrimination analyses to evaluate the performance of both predictive models. Discrimination was assessed by calculating the area under the ROC curve (C-statistic with 95% confidence interval). Calibration was assessed by using the Hosmer-Lemeshow test, through calculation of the slope and intercept, and visually by generating a calibration plot, evaluating the level of agreement between predicted probabilities versus observed outcomes. Overall model performance was evaluated using the Brier score as a composite measure of both model discrimination and calibration. Results We studied 347 patients, 31.1% were women, with a mean age of 72.1 ± 12.7 years, 52.4% with cardiovascular disease and 58.8% diabetics. At the start, the mean eGFR was 20.7 ± 5.0 ml/min and the median urine albumin-creatinine ratio was 327 (IQR 52-1118) mg/g. At 2, 4 and 5 years the percentage of patients who required KRT was 20.2%, 38.3% and 45.7% respectively, while 12.7% and 23.6% died at 2 and 4 years respectively, before starting KRT. For KTR both models had an excellent discrimination. For KFRE-2 and Grams-2 the AUC was 0.896 (95% CI 0.858-0.933) and 0.904 (95% CI 0.866-0.941) respectively, for Grams-4 the AUC was 0.842 (95% CI 0.801-0.884), and for KFRE-5 the AUC was 0.805 (95% CI 0.751-0.859). For death before KTR the Grams model demonstrated an acceptable discrimination, with an AUC of 0.726 (95% CI 0.646-0.806) and 0.749 (95% CI 0.690-0.809) for Grams-2 and Grams-4 respectively. There was excellent calibration for KRT for both models, the Hosmer-Lemeshow test presented a p&amp;gt;0.05 in all cases, the Brier score was less than 0.20. The adjustment was very precise and only in the event of estimated risks greater than 70% at 2 and 4 years is the observed risk overestimated. The calibration of the Grams model to estimate mortality before starting KTR was also excellent, although for estimated risks greater than 50% at 4 years the observed risk is underestimated. Conclusion In a Spanish cohort of patients with CKD G4+, the Grams and KFRE models adequately estimate the risk of KRT. The Grams model provides an acceptable estimate of the risk of death before starting KRT at both 2 and 4 years. It can be considered for treatment planning and information for patients with CKD G4+.

#5815 INTERNATIONAL VARIATIONS IN TRANSITION OF CARE PRACTICES AND TWO-YEAR OUTCOMES IN ADVANCED CHRONIC KIDNEY DISEASE

Abstract Background and Aims The transition to kidney failure is the period of the highest risk for adverse outcomes in chronic kidney disease (CKD). A smooth and timely transition of care, assuring informed and patient-centric decision-making, is paramount to fostering better kidney care. We described the two-year incidence of clinical outcomes and nephrology practices among advanced CKD patients in CKDopps. Method CKDopps is a prospective cohort study designed to describe and evaluate variations in CKD practices and outcomes in nephrologist-led CKD clinics. For this analysis, we included CKDopps participants who reached a three-month average estimated glomerular filtration rate (eGFR) of less than 20 mL/min/1.73 m2 in the US, France, and Brazil. Time at risk for outcomes started at the end of the first three-month window in which the average eGFR was lower than 20 mL/min/1.73 m2 during study follow-up. Education was defined as participation in at least one educational session about KRT modalities. They were considered to have been referred to vascular access (VA) creation if reported in medical records. Education or VA referral happening before the start of follow-up were classified as occurring at baseline. Patients were considered waitlisted if they had been registered on a pre-emptive kidney transplant waiting list. Cumulative incidence functions adjusting for the competing risk of mortality or KRT were used to estimate the 2-year probability of clinical outcomes and planning events. Results 2,645 patients were included – 51% from France, 36% from the US, and 14% from Brazil. Overall, 56% of patients were male, the mean age was 66 ± 14 years, approximately 50% had diabetes, 27% had coronary artery disease, and 16% had heart failure. Patients in Brazil tended to be younger (63 years) than those in France (67) and the US (67); patients in the US had the greatest burden of cardiovascular comorbidities. The mean eGFR at the study baseline was 16.6 mL/min/1.73m² (15.4 in Brazil, 15.9 in the US, and 17.3 in France). Over a median follow-up of 15.7 [7.2–24] months, 1140 patients (43.1%) started KRT, whereas 377 (14.3%) died before KRT. The 2-year cumulative incidence of KRT was 32% in Brazil, 33% in France, and 44% in the US (Figure 1). The median eGFR at KRT initiation was 11.7 in Brazil, 9.0 in France, and 10.3 in the US. Pre-KRT death risk in two years was 7.3% in Brazil, 10.9% in France, and 16.4% in the US. In two years, approximately one-third of patients had a VA created across countries (Table 1). The probability of transplant waitlisting was higher in France and the US, while patient-reported KRT education was more common in Brazil (Table 1). Conclusion In this international analysis of advanced CKD patients, we found important variations in nephrology practice and outcomes across countries. Patients in the US have a higher risk of both pre-KRT death and KRT. Patient-reported education was far more common in Brazil than in the US and France. Although patients in Brazil are referred for VA creation earlier in the course of advanced CKD, 2-year cumulative incidences for such are similar across countries. The 2-year probability of pre-emptive kidney transplant listing was higher in France and the US. Further international studies evaluating risk factors for adverse outcomes and barriers to KRT planning among advanced CKD patients are warranted.

#5890 THE IMPACT OF CKD STATUS BEFORE KIDNEY TRANSPLANTION ON ALPHATORQUEVIRUS DNA LEVELS

Abstract Background and Aims Torque teno virus (TTV) is a non-pathogenic anellovirus whose replication kinetics reflects the overall state of immunosuppression. Although chronic kidney disease (CKD) induces a well-stabilised dysfunction of the immune system, long-term use of renal replacement therapies (RRT) itself could also modify the immune response. Method We analyzed TTV DNA loads at baseline (in the pre-transplant assessment), day 7 and months 1, 3,6 and 12 after kidney transplantation (KT). Recipients were categorized according to their RRT status: pre-emptive KT (pre-KT), hemodialysis (HD) and peritoneal dialysis (PD). TTV DNA load was measured by real-time polymerase chain reaction. Results A total of 221 CKD patients were analyzed. The mean age was 53.9 ± 15.7 years, 72.4% were males, and hypertension (85.1%) and diabetes (30.1%) were the most common comorbidities. According to the pre-transplant TTR status, 159 (72.0%) were on HD, 35 (15.8%) on PD and 27 (12.2%) received pre-KT. There were no differences in baseline comorbidities or age between patients according to their RRT status, except for residual diuresis (P &amp;lt;0.01). HD patients had higher serum albumin levels than patients receiving pre-KT or PD (4.4 ± 0.5 vs. 4.1 ± 0.6 vs. 3.9 ± 0.4 g/dL, respectively, P &amp;lt;0.01). PD patients exhibited higher TTV DNA load (3.4 ±1.2 log10 copies/mL) than HD (2.8 ± 1.6 log10 copies/mL) or pre-KT patients (2.4 ± 2.1 log10 copies/mL), although the differences were not statistically significant. PD patients had lower time on dialysis than HD patients (18.4± 16.2 vs. 37.5± 53.6 months, respectively; P = 0.038). Although PD patients had higher TTV DNA load during the post-transplant follow-up than HD and pre-KT patients, viral kinetics were comparable across these three groups by month 12 after transplantation. Time on dialysis was not associated with TTV DNA load (P = 0.18). RRT status was not associated with the incidence of post-transplant infection or a composite of opportunistic infection and/or de novo malignancy. Conclusion TTV DNA load could be useful identifying KT recipients at high risk of immunosuppression-related complications. Although PD patients presented a non-significant higher TTV DNA load, we did not find differences according to the modality of prior RRT or the time on dialysis.

#6375 HYPOPROTEIC DIET SUPPLEMENTED WITH KETOANALOGUES VERSUS CONVENTIONAL DIET IN PATIENTS WITH ADVANCED DIABETIC KIDNEY DISEASE AND SEVERE PROTEINURIA

Abstract Background and Aims Low-protein diets seem to have an important role in the management of advanced chronic kidney disease (CKD). In addition, this type of nutritional regimen may defer kidney replacement therapy by improving metabolic abnormalities. However, low-protein diets (LPDs) may be more difficult to integrate in patients with diabetic kidney disease (DKD), because of the already complex dietary intervention in these patients. This is a comparative study that aimed to assess the effects of a ketoanalogue-supplemented low-protein diet (sLPD) versus a conventional diet on the progression of CKD and proteinuria in patients with advanced DKD. Method Ninety-seven adult patients with DKD and heavy proteinuria (&amp;gt;3g/g creatininuria) who proved to be compliant to protein restriction in a 3-month run-in phase were enrolled to receive a LPD (0.6g mixed protein/kg-day) supplemented with ketoanalogues of essential amino acids (Ketosteril®, Bad Homburg, Germany, 1 tb/10 kg dry ideal body weight per day) for 12 months. Ninety-two patients completed the study (5 patients received preemptive kidney transplant). The control group was made up of seventy-four adult patients with DKD and heavy proteinuria who received a conventional diet for 12 months. Efficacy outcomes were variation of the estimated glomerular filtration (eGF) and variation of proteinuria. Results At baseline, patients from the sLPD group had a median age of 61 years (95% CI 58 to 67), were mostly male (66%) and predominantly on insulin (68%). Patients in the control group had a median age of 60 years (95% CI 56 to 61), 62% were male and, similarly, the majority were on insulin (62%). All patients had poorly controlled diabetes, with a glycated hemoglobin of 8.1% (95% CI 8.0 to 8.3) in the sLPD group and 8.2% (95% CI 7.9 to 8.6) in the conventional-diet group respectively (P = .84). Although the median eGF was different between groups: 24.78 mL/min (95% CI 20.00 to 30.00) in sLPD patients versus 12.61 mL/min (95% CI 11.70 to 13.11) in conventional diet patients (p&amp;lt;0.0001), proteinuria was similar at baseline: 5.26 g/g creatininuria (95% CI 4.98 to 5.22) in sLPD patients and 4.05 g/g creatininuria (95% CI 3.70 to 5.80) in control group patients (P = .44). After 12 months, the decline of eFG (mL/min/month) was four-times slower in the sLPD group versus the control group [0.11 (95% CI 0.1 to 0.14) versus 0.43 (95% CI 0.30 to 0.57), p&amp;lt;0.0001]. A twofold reduction in proteinuria (g/month) was observed in sLPD patients compared to conventional diet patients [0.29 (95% CI 0.28 to 0.32) versus 0.12 (95% CI 0.09 to 0.15), p&amp;lt;0.0001]. Conclusion Low-protein diets supplemented with ketoanalogues of essential amino acids seem to be more efficient in reducing kidney function decline and proteinuria than conventional diets.