Faculty Bibliography

BACKGROUND/UNASSIGNED:With the introduction of sirolimus as medical therapy for lymphangioleiomyomatosis (LAM), an updated evaluation of LAM lung transplant (LT) outcomes and characterization of peritransplant sirolimus use is needed. METHODS/UNASSIGNED:We identified adult LT recipients from 2005-2021 using the Scientific Registry of Transplant Recipients database and stratified by diagnosis (LAM vs other). Multivariable Cox regression was performed to calculate the adjusted hazard ratio for LAM vs other diagnoses. A pharmacy claims database was linked to provide sirolimus prescription information, and a subgroup analysis comparing outcomes with pre- vs posttransplant sirolimus use was performed. RESULTS/UNASSIGNED: = .003). CONCLUSIONS/UNASSIGNED:This study supports lung transplant as a treatment for severe pulmonary LAM and identifies increased mortality associated with pre-LT sirolimus, though this may be due to uncharacterized baseline differences.

BACKGROUND:Parents of pediatric heart transplant (HTx) recipients have a unique perspective on the challenges associated with the transition into adult care networks. We sought to assess parental perceptions of the challenges pediatric HTx recipients face daily and parental concerns around the transition from pediatric care networks. METHODS:A 15-item online survey was developed in partnership with parent-stakeholders and administered to parents of pediatric HTx recipients in September 2023. Closed and open-ended questions assessed (1) the patients' diagnosis, age at diagnosis, and age at transplant, (2) parents' daily concerns about their child's well-being, (3) parents' overall concerns about their child's well-being as they transition into adulthood, (4) parents' perceptions of their child's quality-of-life (QoL) and health, and (5) parents' demographic characteristics. RESULTS:Eighty-six parents completed the survey. On a scale of 1 (worst) to 10 (best), 75% of parents rated their child's overall QoL at 8 or higher and 76% rated their child's health-related QoL at 8 or higher. Parents' daily concerns about their child's well-being included infectious diseases, health behaviors and care management, transplant-related concerns, socialization and education, mental health, and care coordination. Concerns related to the transition into adulthood included health behaviors and self-management, life satisfaction, finances, family, transplant-related concerns, and care coordination. CONCLUSIONS:Although parents of pediatric HTx recipients reported mostly positive QoL outcomes, they have concerns related to care management, life satisfaction, and healthcare access as their children transition into adulthood. Comprehensive transition-specific interventions and guidelines are needed to support families during this high-risk period.

BACKGROUND/UNASSIGNED:Preoperative opioid use (OU) is a strong risk factor for poor postoperative outcomes in other surgical populations but has not been explored in lung transplant (LT) recipients nationally. METHODS/UNASSIGNED:The study identified adult (aged ≥18 years) US lung transplant (LT) recipients from 2011 to 2021 in the Scientific Registry of Transplant Recipients with prescription data through a pharmacy data set. Posttransplantation ventilatory support, infection, and mortality by pretransplantation OU (prescription fill ≤6 months before transplantation) were compared using multivariable regression. RESULTS/UNASSIGNED: = .006). CONCLUSIONS/UNASSIGNED:Pretransplantation OU was the strongest independent risk factor for posttransplantation OU and was associated with greater morbidity and mortality. Reducing pretransplantation and posttransplantation OU could benefit LT recipients and should be explored.

BACKGROUND:Given the cardiovascular, renal, and survival benefits of GLP-1 receptor agonists for diabetes, these agents could be effective among kidney transplant recipients. However, kidney transplant recipients are distinct from GLP-1 receptor agonist trial participants, with longer diabetes duration and severity, greater end-organ damage, increased cardiovascular risk, and multimorbidity. We examined GLP-1 receptor agonist real-world effectiveness and safety in kidney transplant recipients with diabetes. METHODS:This USA-based retrospective cohort study included kidney transplant recipients with type 2 diabetes at transplantation and Medicare as their primary insurance from a national registry linked with Medicare claims. Post-transplantation GLP-1 receptor agonist use was identified through Medicare claims. Death-censored graft loss was estimated using the Fine-Gray sub-distribution hazard model and extended Cox models were used for mortality and safety endpoints. Models incorporated inverse probability of treatment weights. To further test whether bias could affect the main results, a cohort was created in which each GLP-1 receptor agonist user was matched with a kidney transplant recipient who had not started a GLP-1 receptor agonist, was alive with a functioning graft, and had accrued the same amount of post-transplant survival time. FINDINGS/RESULTS:Between Jan 1, 2013 and Dec 31, 2020, we identified 44 536 first time kidney transplant recipients with Medicare as primary payer in the 6 months before and at transplantation. 24 192 patients were excluded as they did not have type 2 diabetes. 2328 patients were ineligible (1916 had missing values and 412 used GLP-1 receptor agonists before transplantation). The primary cohort thus consisted of 18 016 kidney transplant recipients with diabetes. Of these patients, 1969 (10·9%) had at least one GLP-1 receptor agonist prescription filled post-transplant. Compared with patients who had not received a GLP-1 receptor agonist, GLP-1 receptor agonist users were younger (median age at transplant 57 years [IQR 49-64] vs 60 years [51-66], p<0·0001) and more likely to be female (786 [39·9%] vs 5645 [35·2%], p<0·0001). Among GLP-1 receptor agonist users, 552 [28·0%] were non-Hispanic White, 703 [35·7%] were non-Hispanic Black, and 568 [28·8%] were Hispanic. The 5-year unadjusted cumulative incidence of death-censored graft loss from a cohort matched on survival time before GLP-1 receptor agonist initiation was 6·0% for GLP-1 receptor agonist users and 10·7% for non-users (Gray's test p=0·004). The 5-year unadjusted cumulative incidence for mortality from a cohort matched on survival time before GLP-1 receptor agonist initiation was 17·0% for GLP-1 receptor agonist users and 25·8% for non-users (log-rank p=0·0006). The 5-year unadjusted cumulative incidence for mortality was 13·5% for GLP-1 receptor agonist users and 19·9% for non-users (log-rank p<0·0001). GLP-1 receptor agonist use was associated with a 49% lower incidence of death-censored graft loss (adjusted subhazard ratio [aSHR] 0·51, 95% CI 0·36-0·71; p=0·0001) and 31% lower mortality (adjusted hazard ratio [aHR] 0·69, 95% CI 0·55-0·86; p=0·001). Inferences were robust when matched on survival time (death-censored graft loss aSHR 0·53, 95% CI 0·37-0·75; p=0·0005; mortality aHR 0·70, 95% CI 0·55-0·88; p=0·003). Safety endpoints were rare and not associated with GLP-1 receptor agonists, with the exception of diabetic retinopathy (aHR 1·49, 1·11-2·00; p=0·008). INTERPRETATION/CONCLUSIONS:GLP-1 receptor agonists were associated with better graft and patient survival. Clinical trials are needed to confirm these findings. FUNDING/BACKGROUND:National Institutes of Health.

Unauthorized immigrants and permanent residents may experience challenges in accessing kidney transplantation due to limited healthcare access, socioeconomic and cultural barriers. Understanding the United States (US) national landscape of kidney transplantation for non-citizens may inform policy changes. To evaluate this, we utilized two cohorts from the US national registry (2013-2023): 287,481 adult candidates for first transplant listing and 190,176 adult first transplant recipients. Citizenship was categorized as US citizen (reference), permanent resident, and presumed unauthorized immigrant. Negative binomial regression was used to quantify the incidence rate ratio over time by citizenship status. Cause-specific hazards models, with clustering at the state of listing/transplant, were used to calculate the adjusted hazard ratio of waitlist mortality, kidney transplant, and post-transplant outcomes (mortality/death-censored graft failure) by citizenship category. The crude proportion of presumed unauthorized immigrants listed increased over time (2013: 0.9%, 2023:1.9%). However, after accounting for case mix and waitlist size, there was no change in listing over time. Presumed unauthorized immigrants were less likely to experience waitlist mortality (adjusted Hazard Ratio 0.54, 95% Confidence Interval: 0.46-0.62), were more likely to obtain deceased donor kidney transplant (1.11: 1.05-1.18), but less likely to receive live donor (0.80: 0.71-0.90) or preemptive kidney transplant (0.52: 0.43- 0.62). When stratified by insurance status, presumed unauthorized immigrants on Medicaid were less likely to receive deceased donor kidney transplants compared to their citizen counterparts; however, presumed unauthorized immigrants with Private insurance or Medicare were more likely to receive deceased donor kidney transplants. Presumed unauthorized immigrants were less likely to experience post-transplant death (0.56: 0.43-0.69) and graft failure (0.69: 0.57-0.84). Residents had similar pre- and post-transplant outcomes. Despite the barriers to kidney transplantation faced by presumed unauthorized immigrants and residents in the US, better post-transplant outcomes for presumed unauthorized immigrants compared to citizens persisted, even after accounting for differences in patient characteristics.

INTRODUCTION/BACKGROUND:Some living organ donors will decide to donate again at a later date. Evidence has indicated that this practice may have increased in recent years. We evaluated the incidence and outcomes of this practice to inform counseling of potential repeat donors. METHODS:Using SRTR data from 1994 to 2023, we identified 220 repeat living donors and their 415 recipients. We constructed donor comparison groups using weighting by the odds. We described clinical and lab results at 6 months, 1 year, and 2 years post-donation separately for kidney-second donors and liver-second donors. We compared all-cause graft failure for their recipients with those of comparison donors. RESULTS:The annual count of repeat living donors increased from 5 in 2018 to 25 in 2019 (p < 0.001). Of 220 donors, 159 were liver-second donors (72.3%) and 55 were kidney-second donors (25.0). The percentage of nondirected donations increased from 30.5% at first donation to 53.2% at second donation (p < 0.001). Liver-second donors had one death approximately 2.5 years post-donation. Seventeen were re-admitted and 20 experienced complications requiring an interventional procedure or re-operation. Among kidney-second donors, no deaths, re-admissions, or post-donation complications were reported. Post-donation outcomes in both groups were comparable when evaluated against organ-specific comparison donors. Recipients of repeat living donors experienced graft survival similar to recipients of comparison donors. CONCLUSIONS:Repeat living donation may be a safe practice for carefully selected living donors in the short term; however, long term safety is unknown. Outcomes for recipients are similar to recipients of comparison donors.

KEY POINTS:In frail kidney transplant (KT) candidates with obesity, unintentional weight loss preceding KT evaluation is associated with lower chance of listing. In frail candidates with obesity, both unintentional and intentional weight loss is associated with higher waitlist mortality. Results suggest that in frail candidates with obesity, careful supervision of weight loss prior to KT should be considered, emphasizing strategies to preserve muscle mass and function. BACKGROUND:Unintentional weight loss, a hallmark of frailty, predicts worse post–kidney transplantation (KT) outcomes. However, weight loss in candidates with obesity is often recommended to enhance transplant eligibility. We tested whether pre-evaluation weight change is associated with listing/waitlist mortality, considering intentionality and frailty. METHODS:) enrolled in a prospective multicenter cohort study. We estimated the association between pre-evaluation weight change (stable, gain, unintentional/intentional loss) with chance of listing/waitlist mortality using Cox proportional hazards/competing-risks models. RESULTS:Among candidates with obesity, 48% had stable weight, 17% had weight gain, 16% had unintentional weight loss, and 20% had intentional weight loss over the year before evaluation. Among frail candidates with obesity, stable weight was associated with a 27% lower chance of listing (adjusted hazard ratio [aHR], 0.73; 95% confidence intervals [CI], 0.55 to 0.96), weight gain with a 47% lower chance of listing (aHR, 0.53; 95% CI, 0.34 to 0.80), and unintentional weight loss with a 48% lower chance of listing (aHR, 0.52; 95% CI, 0.32 to 0.84) compared with nonfrail candidates with stable weight. However, in frail candidates with obesity, intentional weight loss was not associated with a significantly lower chance of listing compared with nonfrail candidates with stable weight. In addition, among frail candidates with obesity, stable weight (adjusted subhazard ratio [aSHR], 1.72; 95% CI, 1.01 to 2.90), unintentional weight loss (aSHR, 2.78; 95% CI, 1.23 to 6.27), and intentional weight loss (aSHR, 2.26; 95% CI, 1.05 to 4.85) were associated with higher waitlist mortality compared with nonfrail candidates with stable weight. Among nonfrail candidates, no associations were observed for weight change and frailty status with either chance of listing or waitlist mortality. CONCLUSIONS:Among frail candidates with obesity, unintentional pre-KT weight loss is associated with a lower chance of listing; however, any weight loss is associated with higher waitlist mortality. Our findings suggest that frail candidates with obesity may benefit from clinician supervision of pre-KT weight loss.

Solid organ transplant recipients (SOTRs) suffer more frequent and more severe infections due to their compromised immune responses resulting from immunosuppressive treatments designed to prevent organ rejection. Pharmacological immunosuppression can adversely affect immune responses to vaccination. A cohort of kidney transplant recipients (KTRs) received their third dose of ancestral, monovalent COVID-19 vaccine in the context of a clinical trial and antibody responses to the vaccine strain, as well as two Omicron variants BA.1 and BA.5 were investigated and compared with healthy controls who also received a third dose of mRNA vaccine (HCs). Total IgG and live virus neutralizing antibody titers were reduced in KTRs compared with controls for all variants. KTRs displayed altered IgG subclass switching, with significantly lower IgG3 antibodies. Responses in KTRs were also very heterogeneous, with some individuals showing strong responses but a significant number showing no Omicron-specific neutralizing antibodies. Taken together, immune responses after COVID-19 vaccination in KTRs were not only lower than HCs but highly variable, indicating that simply increasing the number of vaccine doses alone may not be sufficient to provide greater protection in this population. These findings underscore the need for tailored vaccination strategies for immunosuppressed populations, such as KTRs. Alternative formulations and doses of COVID-19 vaccines should be considered for people with severely compromised immune systems, as more frequent vaccinations may not significantly improve the response, especially regarding neutralizing antibodies.IMPORTANCEThis study addresses the challenges faced by kidney transplant recipients (KTRs) in mounting effective immune responses against COVID-19. By evaluating the antibody responses to a third dose of monovalent mRNA COVID-19 vaccine and its effectiveness against Omicron subvariants (BA.1 and BA.5), this study reveals significant reductions in both binding and neutralizing antibodies in KTRs compared with healthy controls. The research highlights altered IgG subclass switching and heterogeneous responses within the KTR population. Reduced recognition of variants, coupled with differences in IgG subclasses, decreases both the quality and quantity of protective antibodies after vaccination in KTRs. These findings underscore the need for tailored vaccination strategies for immunosuppressed populations, such as KTRs. Alternative formulations and doses of COVID-19 vaccines should be considered for people with severely compromised immune systems, as more frequent vaccinations may not significantly improve the response, especially regarding neutralizing antibodies.

Human leukocyte antigen-level matching in US kidney allocation has been deemphasized due to its role in elevating racial disparities. Molecular matching based on eplets might improve risk stratification compared to antigen matching, but the magnitude of racial disparities in molecular matching is not known. To assign eplets unambiguously, we utilized a cohort of 5193 individuals with high-resolution allele-level human leukocyte antigen genotypes from the National Kidney Registry. Using repeated random sampling to simulate donor-recipient genotype pairings based on the ethnic composition of the historical US deceased-donor pool, we profiled the percentage of well-matched donors available for candidates by ethnicity. The prevalence of well-matched donors with 0-DR/DQ eplet mismatch was 3-fold less racially disparate for Black and Asian candidates and 2-fold less for Latino candidates compared to 0-ABDR antigen mismatches. Compared to 0-DR antigen mismatch, 0-DR eplet mismatch was 1.33-fold more racially disparate for Asian and 1.28-fold more for Latino, with similar disparity for Black candidates, whereas 0-DQ eplet mismatch reduced disparities, showing 1.26-fold less disparity for Black, 1.14-fold less for Latino, but 1.26-fold higher for Asian candidates. The prevalence of well-matched donors for candidates of different ethnicities varied according to which molecules were chosen to define a low-risk match.