Faculty Bibliography

BACKGROUND:Brazil has a large public transplant program, but it remains unclear if the kidney waitlist criteria effectively allocate organs. This study aimed to investigate whether gender, ethnicity, clinical characteristics, and Brazilian regions affect the chance of deceased donor kidney transplant (DDKT). METHODS:We conducted a retrospective cohort study using the National Transplant System/Brazil database, which included all patients on the kidney transplant waitlist from January 2012 to December 2022, followed until May 2023. The primary outcome assessed was the chance of DDKT, measured using subdistribution hazard and cause-specific hazard models (subdistribution hazard ratio [sHR]). RESULTS:We analyzed 118 617 waitlisted patients over a 10-year study period. Male patients had an sHR of 1.07 ([95% CI: 1.05-1.10], p < 0.001), indicating a higher chance of DDTK. Patients of mixed race and Yellow/Indigenous ethnicity had lower rates of receiving a transplant compared to Caucasian patients, with sHR of 0.97 (95% CI: 0.95-1) and 0.89 (95% CI: 0.95-1), respectively. Patients from the South region had the highest chance of DDKT, followed by those from the Midwest and Northeast, compared to patients from the Southeast, with sHR of 2.53 (95% CI: 2.47-2.61), 1.21 (95% CI: 1.16-1.27), and 1.10 (95% CI: 1.07-1.13), respectively. The North region had the lowest chance of DDTK, sHR of 0.29 (95% CI: 0.27-0.31). CONCLUSION/CONCLUSIONS:We found that women and racial minorities faced disadvantages in kidney transplantation. Additionally, we observed regional disparities, with the North region having the lowest chance of DDKT and longer times on dialysis before being waitlisted. In contrast, patients in the South regions had a chance of DDKT and shorter times on dialysis before being waitlisted. It is urgent to implement approaches to enhance transplant capacity in the North region and address race and gender disparities in transplantation.

BACKGROUND:The number of living kidney donors in the United States has declined since 2005, with variations based on the donor-recipient relationship. The reasons for this decline are unclear, and strategies to mitigate declined donations remain elusive. We examined the change in donor number monthly (within-year) versus annually (between-years) to inform potentially modifiable factors for future interventions. METHODS:In this registry-based cohort analysis of 141 759 living kidney donors between 1995 and 2019, we used linear mixed-effects models for donor number per month and year to analyze between-year and within-year variation in donation. We used Poisson regression to quantify the change in the number of donors per season before and after 2005, stratified by donor-recipient relationship and zip-code household income tertile. RESULTS:We observed a consistent summer surge in donations during June, July, and August. This surge was statistically significant for related donors (incidence rate ratio [IRR] range: 1.12-1.33) and unrelated donors (IRR range: 1.06-1.16) across donor income tertiles. CONCLUSION/CONCLUSIONS:Our findings indicate lower rates of living kidney donation in non-summer months across income tertiles. Interventions are needed to address barriers to donation in non-summer seasons and facilitate donations throughout the year. Since the Organ Donor Leave Law provides a solid foundation for supporting year-round donation, extending the law's provisions beyond federal employees may mitigate identified seasonal barriers.

INTRODUCTION/BACKGROUND:Frailty and cognitive function are often measured during kidney transplant evaluation. However, patient perspectives on the ethical considerations of this practice are unclear. RESEARCH QUESTION/OBJECTIVE:What are patient perspectives on the use of aging metrics in kidney transplant decision-making? DESIGN/METHODS:One hundred participants who were evaluated for kidney transplantation and were enrolled in an ongoing prospective cohort study (response rate = 61.3%) were surveyed. Participants were informed of the definitions of frailty and cognitive impairment and then asked survey questions regarding the use of these measures of aging to determine kidney transplant candidacy. RESULTS:Participants (75.6%) thought it was unfair to prevent older adults from receiving a kidney transplant based on age, but there was less agreement on whether it was fair to deny frail (46.5%) and cognitively impaired (45.9%) patients from accessing kidney transplantation. Compared to older participants, younger participants had 5.36-times (95%CI:1.94-14.81) the odds of choosing a hypothetical younger, frail patient to list for kidney transplantation than an older, non-frail patient; they also had 3.56-times (95%CI:1.33-9.56) the odds of choosing the hypothetical frail patient with social support rather than a non-frail patient without social support. Participants disagreed on the use of patient age as a listing criterion; 19.5% ranked it as the fairest and 28.7% as the least fair. CONCLUSION/CONCLUSIONS:The patient views highlighted in this study are an important step toward developing ethical guidelines to ensure fair use of frailty, cognitive function, and chronological age for kidney transplant decision-making.

INTRODUCTION/UNASSIGNED:Uremic toxins contributing to increased risk of death remain largely unknown. We used untargeted metabolomics to identify plasma metabolites associated with mortality in patients receiving maintenance hemodialysis. METHODS/UNASSIGNED:We measured metabolites in serum samples from 522 Longitudinal US/Canada Incident Dialysis (LUCID) study participants. We assessed the association between metabolites and 1-year mortality, adjusting for age, sex, race, cardiovascular disease, diabetes, body mass index, serum albumin, Kt/Vurea, dialysis duration, and country. We modeled these associations using limma, a metabolite-wise linear model with empirical Bayesian inference, and 2 machine learning (ML) models: Least absolute shrinkage and selection operator (LASSO) and random forest (RF). We accounted for multiple testing using a false discovery rate (pFDR) adjustment. We defined significant mortality-metabolite associations as pFDR < 0.1 in the limma model and metabolites of at least medium importance in both ML models. RESULTS/UNASSIGNED:limma. CONCLUSION/UNASSIGNED:Quinolinate and mesaconate were significantly associated with a 1-year risk of death in incident patients receiving maintenance hemodialysis. External validation of our findings is needed.

BACKGROUND:The number of deceased donor kidney transplants has been increasing and is at a record high, yet nonuse of kidneys recovered for transplantation has risen to 25.8% following circular kidney allocation system based on 250-nautical-mile circles implemented on March 15, 2021 (KAS250). METHODS:Using Scientific Registry of Transplant Recipients data, we studied all deceased donor kidneys recovered for transplant from March 15, 2019, to January 31, 2023. We calculated the association of multiple factors with kidney nonuse, including increasing recovery of kidneys from nonideal donors, delays in offer acceptance observed under KAS250, and impacts of COVID-19. RESULTS:In the 2 y before KAS250, the nonuse rate was 21.2%. Had this rate continued, 2334 more kidneys would have been transplanted through January 2023. We estimated that about 769 of these nonused kidneys (33%) were associated with offer acceptance delays under KAS250; about 994 of these nonused kidneys (43%) were associated with increased prevalence of nonideal donors: donation after circulatory death donors, older donors, and donors with elevated peak serum creatinine; and about 542 of these nonused kidneys (23%) were associated with an otherwise unexplained gradual upward trend in nonuse of recovered kidneys across the pre-KAS250 and KAS250 eras. The overall impact of COVID-19 on the nonuse rate was not significant. CONCLUSIONS:The rise in kidney nonuse rate was significantly associated with both increased recovery of nonideal donors, and with KAS250 allocation complexity and delays. Increasing recovery of kidneys from nonideal donors benefits patients because recovering more kidneys increases the number of kidneys available for transplant.

BACKGROUND:Sarcopenia has been associated with adverse postoperative outcomes in older age cohorts, but has not been assessed in older adults with inflammatory bowel disease (IBD). Further, current assessments of sarcopenia among all aged individuals with IBD have used various measures of muscle mass as well as cutoffs to define its presence, leading to heterogeneous findings. METHODS:In this single-institution, multihospital retrospective study, we identified all patients aged 60 years and older with IBD who underwent disease-related intestinal resection between 2012 and 2022. Skeletal Muscle Index (SMI) and Total Psoas Index (TPI) were measured at the superior L3 endplate on preoperative computed tomography scans and compared through receiver operating characteristic curve. We then performed multivariable logistic regression to assess risk factors associated with an adverse 30-day postoperative outcome. Our primary outcome included a 30-day composite of postoperative mortality and complications, including infection, bleeding, cardiac event, cerebrovascular accident, acute kidney injury, venous thromboembolism, reoperation, all-cause rehospitalization, and need for intensive care unit-level care. RESULTS:A total of 120 individuals were included. Overall, 52% were female, 40% had ulcerative colitis, 60% had Crohn's disease, and median age at time of surgery was 70 years (interquartile range: 65-75). Forty percent of older adults had an adverse 30-day postoperative outcome, including infection (23%), readmission (17%), acute kidney injury (13%), bleeding (13%), intensive care unit admission (10%), cardiac event (8%), venous thromboembolism (7%), reoperation (6%), mortality (5%), and cerebrovascular accident (2%). When evaluating the predictive performance of SMI vs TPI for an adverse 30-day postoperative event, SMI had a significantly higher area under the curve of 0.66 (95% CI, 0.56-0.76) as compared to 0.58 (95% CI, 0.48-0.69) for TPI (P = .02). On multivariable logistic regression, prior IBD-related surgery (adjusted odds ratio [adjOR] 6.46, 95% CI, 1.85-22.51) and preoperative sepsis (adjOR 5.74, 95% CI, 1.36-24.17) significantly increased the odds of adverse postoperative outcomes, whereas increasing SMI was associated with a decreased risk of an adverse postoperative outcome (adjOR 0.88, 95% CI, 0.82-0.94). CONCLUSIONS:Sarcopenia, as measured by SMI, is associated with an increased risk of postoperative complications among older adults with IBD. Measurement of SMI from preoperative imaging can help risk stratify older adults with IBD undergoing intestinal resection.

BACKGROUND:As the inflammatory bowel disease (IBD) patient population is aging, the prevalence of polypharmacy is rising. However, data exploring the prevalence, risk factors, and clinical outcomes associated with polypharmacy among older adults with IBD are limited. AIMS/OBJECTIVE:To determine (i) prevalence of polypharmacy (≥5 medications) and potentially inappropriate medication (PIM) utilization in older adults with IBD, (ii) changes in medications over time (iii) predictors of polypharmacy, and (iv) the impact of polypharmacy/PIMs on one-year hospitalization rates. METHODS:We conducted a retrospective single-center study of older adults with IBD from September 1st 2011 to December 31st 2022. Wilcoxon-signed rank and McNemar's tests were used to assess changes in polypharmacy between visits, with ordinal logistic regression and Cox proportional hazards models used to determine risk factors for polypharmacy and time to hospitalization, respectively. RESULTS:Among 512 older adults with IBD, 74.0% experienced polypharmacy at initial visit, with 42.6% receiving at least one PIM. Additionally, severe polypharmacy (≥10 medications) was present among 28.6% individuals at index visit and increased to 38.6% by last visit (p<0.01). Multivariable analysis revealed that age ≥70 years, BMI ≥30.0 kg/m2, prior IBD-related surgery, and the presence of comorbidities were associated with polypharmacy. Moreover, severe polypharmacy (adjHR 1.95, 95%CI 1.29-2.92), as well as PIM use (adjHR 2.16, 95%CI 1.37-3.43) among those with polypharmacy, were significantly associated with all-cause hospitalization within a year of index visit. DISCUSSION/CONCLUSIONS:Severe polypharmacy was initially present in more than 25% of older adults with IBD and increased to 34% within 4 years of index visit. Severe polypharmacy, as well as PIM utilization among those with polypharmacy, were also associated with an increased risk of hospitalization at one-year, highlighting the need for deprescribing efforts in this population.

INTRODUCTION/BACKGROUND:Transplants with hearts and lungs from donors with hepatitis C virus (HCV D+) have been proven safe and effective since development of direct-acting antivirals, yet the presence of HCV + persists as a reason to decline organs. METHODS:We identified adult candidates listed January 1, 2015-March 8, 2023 for heart or lung transplant using the Scientific Registry of Transplant Recipients. We identified individual-level and center-level characteristics associated with listing to consider HCV D+ offers using multilevel logistic regression in a multivariable framework. RESULTS:Over the study period, the annual percentage of candidates willing to consider HCV D+ offers increased for both heart (9.5%-74.3%) and lung (7.8%-59.5%), as did the percentage of centers listing candidates for HCV D+ heart (52.9%-91.1%) and lung (32.8%-82.8%) offers. Candidates at centers with more experience with HCV D+ transplants were more likely to consider HCV D+ organ offers. After adjustment, listing center explained 70% and 78% of the residual variance in willingness to consider HCV D+ hearts and lungs, respectively. CONCLUSIONS:Although listing for consideration of HCV D+ offers has increased, it varies by transplant center. Center-level barriers to consideration of HCV D+ organs reduce recipients' transplant access.

BACKGROUND:Since February 2020, exception points have been allocated equivalent to the median model for end-stage liver disease at transplant within 250 nautical miles of the transplant center (MMaT/250). We compared transplant rate and waitlist mortality for hepatocellular carcinoma (HCC) exception, non-HCC exception, and non-exception candidates to determine whether MMaT/250 advantages (or disadvantages) exception candidates. METHODS:Using Scientific Registry of Transplant Recipients data, we identified 23 686 adult, first-time, active, deceased donor liver transplant (DDLT) candidates between February 4, 2020, and February 3, 2022. We compared DDLT rates using Cox regression, and waitlist mortality/dropout using competing risks regression in non-exception versus HCC versus non-HCC candidates. RESULTS:Within 24 mo of study entry, 58.4% of non-exception candidates received DDLT, compared with 57.8% for HCC candidates and 70.5% for non-HCC candidates. After adjustment, HCC candidates had 27% lower DDLT rate (adjusted hazard ratio = 0.680.730.77) compared with non-exception candidates. However, waitlist mortality for HCC was comparable to non-exception candidates (adjusted subhazard ratio [asHR] = 0.931.031.15). Non-HCC candidates with pulmonary complications of cirrhosis or cholangiocarcinoma had substantially higher risk of waitlist mortality compared with non-exception candidates (asHR = 1.271.702.29 for pulmonary complications of cirrhosis, 1.352.043.07 for cholangiocarcinoma). The same was not true of non-HCC candidates with exceptions for other reasons (asHR = 0.540.881.44). CONCLUSIONS:Under MMaT/250, HCC, and non-exception candidates have comparable risks of dying before receiving liver transplant, despite lower transplant rates for HCC. However, non-HCC candidates with pulmonary complications of cirrhosis or cholangiocarcinoma have substantially higher risk of dying before receiving liver transplant; these candidates may merit increased allocation priority.