Faculty Bibliography

Older compatible living donor kidney transplant (CLDKT) recipients have higher mortality and death-censored graft failure (DCGF) compared to younger recipients. These risks may be amplified in older incompatible living donor kidney transplant (ILDKT) recipients who undergo desensitization and intense immunosuppression. In a 25-center cohort of ILDKT recipients transplanted between September 24, 1997, and December 15, 2016, we compared mortality, DCGF, delayed graft function (DGF), acute rejection (AR), and length of stay (LOS) between 234 older (age ≥60 years) and 1172 younger (age 18-59 years) recipients. To investigate whether the impact of age was different for ILDKT recipients compared to 17 542 CLDKT recipients, we used an interaction term to determine whether the relationship between posttransplant outcomes and transplant type (ILDKT vs CLDKT) was modified by age. Overall, older recipients had higher mortality (hazard ratio: _1.632.07_2.65, P < .001), lower DCGF (hazard ratio: _0.360.53_0.77, P = .001), and AR (odds ratio: _0.390.54_0.74, P < .001), and similar DGF (odds ratio: _0.461.03_2.33, P = .9) and LOS (incidence rate ratio: _0.880.98_1.10, P = 0.8) compared to younger recipients. The impact of age on mortality (interaction P = .052), DCGF (interaction P = .7), AR interaction P = .2), DGF (interaction P = .9), and LOS (interaction P = .5) were similar in ILDKT and CLDKT recipients. Age alone should not preclude eligibility for ILDKT.

INTRODUCTION:Liver allocation changes have led to increased travel and expenditures, highlighting the need to efficiently identify marginal livers suitable for transplant. We evaluated the validity of existing non-invasive liver quality tests and a novel machine learning-based model at predicting deceased donor macrosteatosis >30%. METHODS:We compared previously-validated non-invasive tests and a novel machine learning-based model to biopsies in predicting macrosteatosis >30%. We also tested them in populations enriched for macrosteatosis. RESULTS:The Hepatic Steatosis Index area-under-the-curve (AUC) was 0.56. At the threshold identified by Youden's J statistic, sensitivity, specificity, positive, and negative predictive values were 49.6%, 58.9%, 14.0%, and 89.7%. Other tests demonstrated comparable results. Machine learning produced the highest AUC (0.71). Even in populations enriched for macrosteatosis, no test was sufficiently predictive. CONCLUSION:Commonly used clinical scoring systems and a novel machine learning-based model were not clinically useful, highlighting the importance of pre-procurement biopsies to facilitate allocation.

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.

Machine learning (ML) models have recently shown potential for predicting kidney allograft outcomes. However, their ability to outperform traditional approaches remains poorly investigated. Therefore, using large cohorts of kidney transplant recipients from 14 centers worldwide, we developed ML-based prediction models for kidney allograft survival and compared their prediction performances to those achieved by a validated Cox-Based Prognostication System (CBPS). In a French derivation cohort of 4000 patients, candidate determinants of allograft failure including donor, recipient and transplant-related parameters were used as predictors to develop tree-based models (RSF, RSF-ERT, CIF), Support Vector Machine models (LK-SVM, AK-SVM) and a gradient boosting model (XGBoost). Models were externally validated with cohorts of 2214 patients from Europe, 1537 from North America, and 671 from South America. Among these 8422 kidney transplant recipients, 1081 (12.84%) lost their grafts after a median post-transplant follow-up time of 6.25 years (Inter Quartile Range 4.33-8.73). At seven years post-risk evaluation, the ML models achieved a C-index of 0.788 (95% bootstrap percentile confidence interval 0.736-0.833), 0.779 (0.724-0.825), 0.786 (0.735-0.832), 0.527 (0.456-0.602), 0.704 (0.648-0.759) and 0.767 (0.711-0.815) for RSF, RSF-ERT, CIF, LK-SVM, AK-SVM and XGBoost respectively, compared with 0.808 (0.792-0.829) for the CBPS. In validation cohorts, ML models' discrimination performances were in a similar range of those of the CBPS. Calibrations of the ML models were similar or less accurate than those of the CBPS. Thus, when using a transparent methodological pipeline in validated international cohorts, ML models, despite overall good performances, do not outperform a traditional CBPS in predicting kidney allograft failure. Hence, our current study supports the continued use of traditional statistical approaches for kidney graft prognostication.

IMPORTANCE:In January 2011, the US Food and Drug Administration (FDA) announced a mandate to limit acetaminophen (paracetamol) to 325 mg/tablet in combination acetaminophen and opioid medications, with manufacturer compliance required by March 2014. OBJECTIVE:To assess the odds of hospitalization and the proportion of acute liver failure (ALF) cases with acetaminophen and opioid toxicity prior to and after the mandate. DESIGN, SETTING, AND PARTICIPANTS:This interrupted time-series analysis used hospitalization data from 2007-2019 involving ICD-9/ICD-10 codes consistent with both acetaminophen and opioid toxicity from the National Inpatient Sample (NIS), a large US hospitalization database, and ALF cases from 1998-2019 involving acetaminophen and opioid products from the Acute Liver Failure Study Group (ALFSG), a cohort of 32 US medical centers. For comparison, hospitalizations and ALF cases consistent with acetaminophen toxicity alone were extracted from the NIS and ALFSG. EXPOSURES:Time prior to and after the FDA mandate limiting acetaminophen to 325 mg in combination acetaminophen and opioid products. MAIN OUTCOMES AND MEASURES:Odds of hospitalization involving acetaminophen and opioid toxicity and percentage of ALF cases from acetaminophen and opioid products prior to and after the mandate. RESULTS:In the NIS, among 474 047 585 hospitalizations from Q1 2007 through Q4 2019, there were 39 606 hospitalizations involving acetaminophen and opioid toxicity; 66.8% of cases were among women; median age, 42.2 (IQR, 28.4-54.1). In the ALFSG, from Q1 1998 through Q3 2019, there were a total of 2631 ALF cases, of which 465 involved acetaminophen and opioid toxicity; 85.4% women; median age, 39.0 (IQR, 32.0-47.0). The predicted incidence of hospitalizations 1 day prior to the FDA announcement was 12.2 cases/100 000 hospitalizations (95% CI, 11.0-13.4); by Q4 2019, it was 4.4/100 000 hospitalizations (95% CI, 4.1-4.7) (absolute difference, 7.8/100 000 [95% CI, 6.6-9.0]; P < .001). The odds of hospitalizations with acetaminophen and opioid toxicity increased 11%/y prior to the announcement (odds ratio [OR], 1.11 [95% CI, 1.06-1.15]) and decreased 11%/y after the announcement (OR, 0.89 [95% CI, 0.88-0.90]). The predicted percentage of ALF cases involving acetaminophen and opioid toxicity 1 day prior to the FDA announcement was 27.4% (95% CI, 23.3%-31.9%); by Q3 2019, it was 5.3% (95% CI, 3.1%-8.8%) (absolute difference, 21.8% [95% CI, 15.5%-32.4%]; P < .001). The percentage of ALF cases involving acetaminophen and opioid toxicity increased 7% per year prior to the announcement (OR, 1.07 [95% CI, 1.03-1.1]; P < .001) and decreased 16% per year after the announcement (OR, 0.84 [95% CI, 0.77-0.92]; P < .001). Sensitivity analyses confirmed these findings. CONCLUSIONS AND RELEVANCE:The FDA mandate limiting acetaminophen dosage to 325 mg/tablet in prescription acetaminophen and opioid products was associated with a statistically significant decrease in the yearly rate of hospitalizations and proportion per year of ALF cases involving acetaminophen and opioid toxicity.

BACKGROUND:Chronic Kidney Disease (CKD) Epidemiology Collaboration eGFR 2021 formula removed Black race from the 2009 equation. Unintended consequences may lead to reclassifying Black living kidney donors as having more advanced CKD, exacerbating racial disparities in living donation. METHODS:We used national data to quantify CKD stage reclassification based on eGFR for Black living donors both pre- and post-donation. RESULTS:Among 6365 Black living donors, 17.7% were reclassified as having a higher CKD stage pre-donation with the 2021 formula. Among 4149 Black living donors with at least 2 creatinine measurements post-donation, 25.5% were reclassified as having a higher CKD stage post-donation with the 2021 formula. CONCLUSION:Eliminating race in the formula may inappropriately label Black potential donors with CKD. These data highlight the need for a validated eGFR formula for donors, use of measured and not eGFR, and education of non-transplant providers regarding interpretation of CKD staging in living donation.

Pig-to-human xenotransplantation is rapidly approaching the clinical arena; however, it is unclear which immunomodulatory regimens will effectively control human immune responses to pig xenografts. We transplanted a gene-edited pig kidney into a brain-dead human recipient on pharmacologic immunosuppression and studied the human immune response to the xenograft using spatial transcriptomics and single-cell RNA sequencing. Human immune cells were uncommon in the porcine kidney cortex early after xenotransplantation and consisted of primarily myeloid cells. Both the porcine resident macrophages and human infiltrating macrophages expressed genes consistent with an alternatively activated, anti-inflammatory phenotype. No significant infiltration of human B or T cells into the porcine kidney xenograft was detected. Altogether, these findings provide proof of concept that conventional pharmacologic immunosuppression is sufficient to restrict infiltration of human immune cells into the xenograft early after compatible pig-to-human kidney xenotransplantation.

INTRODUCTION:In the published studies of early liver transplantation (LT) for alcohol-associated hepatitis (AH), patients with a prior liver decompensation are excluded. The appropriateness of this criteria is unknown. METHODS:Among 6 American Consortium of Early Liver Transplantation for Alcohol-Associated Hepatitis sites, we included consecutive early LT for clinically diagnosed AH between 2007 and 2020. Patients were stratified as first vs prior history of liver decompensation, with the latter defined as a diagnosis of ascites, hepatic encephalopathy, variceal bleeding, or jaundice, and evidence of alcohol use after this event. Adjusted Cox regression assessed the association of first (vs prior) decompensation with post-LT mortality and harmful (i.e., any binge and/or frequent) alcohol use. RESULTS:A total of 241 LT recipients (210 first vs 31 prior decompensation) were included: median age 43 vs 38 years ( P = 0.23), Model for End-Stage Liver Disease Sodium score of 39 vs 39 ( P = 0.98), and follow-up after LT 2.3 vs 1.7 years ( P = 0.08). Unadjusted 1- and 3-year survival among first vs prior decompensation was 93% (95% confidence interval [CI] 89%-96%) vs 86% (95% CI 66%-94%) and 85% (95% CI 79%-90%) vs 78% (95% CI 57%-89%). Prior (vs first) decompensation was associated with higher adjusted post-LT mortality (adjusted hazard ratio 2.72, 95% CI 1.61-4.59) and harmful alcohol use (adjusted hazard ratio 1.77, 95% CI 1.07-2.94). DISCUSSION:Prior liver decompensation was associated with higher risk of post-LT mortality and harmful alcohol use. These results are a preliminary safety signal and validate first decompensation as a criterion for consideration in early LT for AH patients. However, the high 3-year survival suggests a survival benefit for early LT and the need for larger studies to refine this criterion. These results suggest that prior liver decompensation is a risk factor, but not an absolute contraindication to early LT.

Acute hepatitis B virus infection is a common contraindication to liver transplantation surgery in the setting of active HIV viremia. This is a case report of a patient with decompensated cirrhosis and acute renal failure in the setting of hepatitis B virus reactivation and active HIV viremia who underwent liver transplantation with sustained graft survival.

OBJECTIVE:Recent changes to the Chronic Kidney Disease Epidemiology Collaboration estimated glomerular filtration rate (eGFR) formula (2021 CKD-EPI) removed race from the 2009 formula, increasing the number of Black people classified as having CKD, but these changes may impact eligibility and/or dosing for antiobesity medications. This study estimated the number of people with obesity nationwide who might have pharmacotherapy options impacted by the new formula. METHODS:Using National Health and Nutrition Examination Survey (NHANES) cohort study data, the number of people eligible for antiobesity medication was estimated, and the number who would require a dosage reduction or would no longer be eligible for specific medications based on the new eGFR formula was also estimated. RESULTS:Among 16,412,571 Black and 109,654,751 non-Black people eligible for antiobesity medication, 911,336 (6.1%) Black and 6,925,492 (6.6%) non-Black people had ≥CKD stage 3 by the 2009 CKD-EPI formula. Applying the 2021 CKD-EPI formula, 1,260,969 (8.5%) Black people and 4,989,919 (4.7%) non-Black people had ≥CKD stage 3. For medications requiring renal adjustment, the number of Black people who would require a lower dose or be precluded from using a medication increased by 24.7% to 50.2%. CONCLUSIONS:These findings highlight the importance of measuring-rather than estimating-GFR in Black people with CKD when considering many antiobesity pharmacotherapy options.