Segev, Dorry L.

ABSTRACT Background Kidney disease significantly increases the risk of dementia, including among kidney transplant (KTx) recipients. To date, the cost implications of dementia after KTx are not well described. Methods We performed a retrospective cohort study of US Renal Data System (USRDS) data (2006–2020) to estimate cost of care for ≥65‐year‐old Medicare insured KTx recipients (2006–2020) with newly diagnosed dementia ( n = 3285), compared to propensity‐matched controls without dementia ( n = 6570). KTx recipients age 65+ years with post‐KTx dementia were identified by diagnosis codes, and costs were computed based on payments on Medicare claims. Average costs per month, marginal costs per month, and cumulative costs were compared after dementia diagnosis versus after the equivalent time post‐KTx in controls. Results Dementia was diagnosed at a mean of 5.1 ± 3.4 years post‐KTx. Patients' characteristics were well matched in cases versus controls, including age (mean: 70.1 vs. 69.9 years), sex (38.4% vs. 37.9% women), race (23.7% vs. 22.2% African American), and cause of ESKD (45.4% vs. 43.7% diabetes). Over 4 years post‐KTx, dementia was associated with reduced survival (27% vs. 68%) along with $66 145 (95% CI $51 560‐$78 489) higher Medicare spending. Average monthly costs in dementia patients reached a maximum of $12 713 and exceeded the cost of unaffected patients by up to $9789 per month. Conclusions Post‐KTx dementia dramatically increased resource utilization and reduced post‐KTx surivival. These findings highlight the need for care pathways that better integrate cognitive health assessment and management into the care of KTx candidates and recipients.

Abstract Background and Aims The iBox is a validated prognostication system predicting long-term kidney allograft failure. Recently, it received regulatory endorsement by EMA, for surrogate endpoint for clinical trials. As the iBox system was primarily built using a deep phenotyped cohort, there is a need for proof of validity in extended clinical scenarios, geographic distinct medico-economic cohorts and transplant allocation systems. Method 10,851 transplant recipients were included from 17 academic medical centers from France, Belgium, Spain, Germany, Finland, United States, Brazil and Argentina. We applied to these cohorts the iBox algorithm that integrates eight independent prognostic factors including the time from transplantation to risk evaluation, functional parameters (eGFR, proteinuria), allograft histological lesions (IFTA, g+ptc, i+t, cg Banff scores), and circulating anti-HLA DSA. We stratified the performances of the iBox according to several real-life scenarios, including: 1) iBox + different eGFR formulas (MDRD186, MDRD175, CKD-Epi); 2) iBox + urinary dipstick; 3) iBox Functional + Structural (absence of DSA measurements); 4) iBox functional + Immunological (absence of histology); 5) iBox in response to treatment in T-cell mediated rejection (TCMR); 6) iBox for in response to treatment antibody mediated rejection (ABMR) clinical trials. The performances of the iBox system were assessed with the discrimination (C-index) and calibration. Results The derivation cohort included 4,000 recipients from France, and the international external validation cohort included 6,851 recipients from Europe (France, Belgium, Spain, Germany, Finland n = 4,643), the United States (n = 1,537) and South America (Brazil, Argentina n = 671). The mean recipient age was 50.26 years (14.05) with a median follow-up after evaluations of 5.41 years [IQR: 3.26 to 7]. 1336 patients (12.31%) lost their graft during the study follow-up. The performances of the iBox were confirmed in the different real-life setting with the following C-Index: 1) iBox + different eGFR formulas (MDRD186, MDRD175, CKD-Epi) 0.81; 2) iBox + urinary dipstick 0.80; 3) iBox Functional + Structural (histology) 0.80 (derivation) and 0.84 (validation); 4) iBox functional + Immunological 0.80 (derivation) and 0.83 (validation); 5) iBox in response to treatment in T-cell mediated rejection 0.81; 6) iBox for in response to treatment antibody mediated rejection trials 0.81. The score showed an accurate calibration in every scenario. Conclusion The iBoxEXTENDED trial confirms in various medico-economic settings the performances transportability and surrogacy of the iBox system, further reinforcing its use as a surrogate end point for clinical trials including TCMR and ABMR.

AbstractBackground and AimsIdentifying international differences in utilization and outcomes of liver transplantation (LT) after donation after circulatory death (DCD) donation provides a unique opportunity for benchmarking and population‐level insight.MethodsAdult (≥18 years) LT data between 2008 and 2018 from the UK and US were used to assess mortality and graft failure after DCD LT. We used time‐dependent Cox‐regression methods to estimate hazard ratios (HR) for risk‐adjusted short‐term (0–90 days) and longer‐term (90 days–5 years) outcomes.ResultsOne‐thousand five‐hundred‐and‐sixty LT receipts from the UK and 3426 from the US were included. Over the study period, the use of DCD livers increased from 15.7% to 23.9% in the UK compared to 5.1% to 7.6% in the US. In the UK, DCD donors were older (UK:51 vs. US:33 years) with longer cold ischaemia time (UK: 437 vs. US: 333 min). Recipients in the US had higher Model for End‐stage Liver Disease (MELD) scores, higher body mass index, higher proportions of ascites, encephalopathy, diabetes and previous abdominal surgeries. No difference in the risk‐adjusted short‐term mortality or graft failure was observed between the countries. In the longer‐term (90 days–5 years), the UK had lower mortality and graft failure (adj.mortality HR:UK: 0.63 (95% CI: 0.49–0.80); graft failure HR: UK: 0.72, 95% CI: 0.58–0.91). The cumulative incidence of retransplantation was higher in the UK (5 years: UK: 11.9% vs. 4.6%; p < .001).ConclusionsFor those receiving a DCD LT, longer‐term post‐transplant outcomes in the UK are superior to the US, however, significant differences in recipient illness, graft quality and access to retransplantation were seen between the two countries.

Objective: To examine whether body mass index (BMI) changes modify the association between kidney donation and incident hypertension. Background: Obesity increases hypertension risk in both general and living kidney donor (LKD) populations. Donation-attributable risk in the context of obesity, and whether weight change modifies that risk, is unknown. Methods: Nested case-control study among 1558 adult LKDs (1976–2020) with obesity (median follow-up: 3.6 years; interquartile range: 2.0–9.4) and 3783 adults with obesity in the Coronary Artery Risk Development in Young Adults (CARDIA) and Atherosclerosis Risk in Communities (ARIC) studies (9.2 y; interquartile range: 5.3–15.8). Hypertension incidence was compared by donor status using conditional logistic regression, with BMI change investigated for effect modification. Results: Overall, LKDs and nondonors had similar hypertension incidence [incidence rate ratio (IRR): 1.16, 95% confidence interval (95% CI): 0.94–1.43, P=0.16], even after adjusting for BMI change (IRR: 1.25, 95% CI: 0.99–1.58, P=0.05). Although LKDs and nondonors who lost >5% BMI had comparable hypertension incidence (IRR: 0.78, 95% CI: 0.46–1.34, P=0.36), there was a significant interaction between donor and >5% BMI gain (multiplicative interaction IRR: 1.62, 95% CI: 1.15–2.29, P=0.006; relative excess risk due to interaction: 0.90, 95% CI: 0.24–1.56, P=0.007), such that LKDs who gained weight had higher hypertension incidence than similar nondonors (IRR: 1.83, 95% CI: 1.32–2.53, P<0.001). Conclusions: Overall, LKDs and nondonors with obesity had similar hypertension incidence. Weight stability and loss were associated with similar hypertension incidence by donor status. However, LKDs who gained >5% saw increased hypertension incidence versus similar nondonors, providing support for counseling potential LKDs with obesity on weight management postdonation.

Abstract The authors have requested that this preprint be removed from Research Square.

Background. Desensitization protocols for HLA-incompatible living donor kidney transplantation (ILDKT) vary across centers. The impact of these, as well as other practice variations, on ILDKT outcomes remains unknown. Methods. We sought to quantify center-level variation in mortality and graft loss following ILDKT using a 25-center cohort of 1358 ILDKT recipients with linkage to Scientific Registry of Transplant Recipients for accurate outcome ascertainment. We used multilevel Cox regression with shared frailty to determine the variation in post-ILDKT outcomes attributable to between-center differences and to identify any center-level characteristics associated with improved post-ILDKT outcomes. Results. After adjusting for patient-level characteristics, only 6 centers (24%) had lower mortality and 1 (4%) had higher mortality than average. Similarly, only 5 centers (20%) had higher graft loss and 2 had lower graft loss than average. Only 4.7% of the differences in mortality (P < 0.01) and 4.4% of the differences in graft loss (P < 0.01) were attributable to between-center variation. These translated to a median hazard ratio of 1.36 for mortality and 1.34 of graft loss for similar candidates at different centers. Post-ILDKT outcomes were not associated with the following center-level characteristics: ILDKT volume and transplanting a higher proportion of highly sensitized, prior transplant, preemptive, or minority candidates. Conclusions. Unlike most aspects of transplantation in which center-level variation and volume impact outcomes, we did not find substantial evidence for this in ILDKT. Our findings support the continued practice of ILDKT across these diverse centers.

AbstractPrescription narcotic use among living kidney donors is not well described. Using a unique database that integrates national registry identifiers for living kidney donors (1987–2007) in the United States with billing claims from a private health insurer (2000–2007), we identified pharmacy fills for prescription narcotic medications in periods 1–4 and >4 yr post‐donation and estimated relative likelihoods of post‐donation narcotic use by Cox regression. We also compared narcotic fill rates and medication possession ratios (MPRs, defined as (days of medication supplied)/(days observed)), between donors and age‐ and sex‐matched non‐donors. Overall, rates of narcotic medication fills were 32.3 and 32.4 per 100 person‐years in periods 1–4 and >4 yr post‐donation. After age and race adjustment, women were approximately twice as likely as men to fill a narcotic prescription in years 1–4 (adjusted hazard ratio, aHR, 2.28; 95% confidence interval, CI, 1.86–2.79) and >4 yr (aHR 1.70; 95% CI 1.50–1.93). MPRs in donors were low (<2.5% days exposed), and lower than among age‐ and sex‐matched non‐donors. Prescription narcotic medication use is more common among women than men in the intermediate term after live kidney donation. Overall, total narcotic exposure is low, and lower than among non‐donors from the general population.