Faculty Bibliography

BACKGROUND:Extended-course enoxaparin is increasingly used after bariatric surgery to prevent venous thromboembolism (VTE), the leading cause of death after bariatric surgery. Direct oral anticoagulants are widely used for extended thromboprophylaxis outside of bariatric surgery and offered to patients in our program who cannot tolerate or obtain enoxaparin. We evaluated the safety and efficacy of apixaban 2.5 mg twice daily relative to a weight-based dose of enoxaparin 40 mg or 60 mg twice daily for 30 days after discharge following sleeve gastrectomy. METHODS:Patients aged ≥18 years who underwent laparoscopic sleeve gastrectomy from 2019 to 2024 at a single high-volume urban academic center were included. Bleeding and thrombosis outcomes within 30 days were compared between patients receiving enoxaparin 40 mg twice daily or apixaban 2.5 mg twice daily. Weighted modified Poisson analyses were used to obtain covariate balance and assess differences in bleeding and thrombosis events. RESULTS:A total of 5921 patients were included for analysis (5274 enoxaparin 40 mg twice daily, 486 enoxaparin 60 mg twice daily, and 161 apixaban 2.5 mg twice daily). The 30-day thrombosis rate was significantly lower with enoxaparin versus apixaban (.1% versus 1.9%, P < .001). The composite outcome (VTE, portomesenteric venous thrombosis, and major/minor bleeding) was also significantly lower with enoxaparin versus apixaban (1.7% versus 5.6%, P < .01). In adjusted analyses, apixaban was associated with a relative risk of 12.09 for thrombosis (95% confidence interval [CI], 5.71-31.18), 1.93 for bleeding (95% CI, 1.27-3.00), and 2.59 (95% CI, 2.06-3.27) for any adverse outcome relative to enoxaparin. CONCLUSION/CONCLUSIONS:Enoxaparin is associated with both lower thrombosis and bleeding rates compared with apixaban for extended thromboprophylaxis after sleeve gastrectomy.

Since their early development in the 1980s, Simulated Allocation Models (SAMs) have helped policymakers forecast the impact of proposed allocation policy changes on patient outcomes before implementation. In the United States, models like the Kidney-Pancreas Simulated Allocation Model, Liver Simulated Allocation Model, and Thoracic Simulated Allocation Model have been instrumental in shaping organ allocation policies. Analogous models have emerged globally, including the ETKidney and Eurotransplant Liver Allocation System simulators for the Eurotransplant region, to address country and region-specific allocation challenges. This review categorizes and compares SAMs based on their core assumptions, data, and modeling approaches. We highlight challenges in model validation, the use of synthetic data, and model transparency. While simplifying assumptions are often necessary because of limited data, their influence on results should be clearly communicated to ensure policymakers can interpret model predictions accurately. Furthermore, model validation using both retrospective and prospective data is essential to assess performance under evolving policies. Greater transparency through open-source models, detailed reporting of assumptions, and validation efforts can enhance collaboration, reproducibility, and confidence in transplant research. By providing a global perspective on SAMs, this review aims to inform future research and policy development, promoting evidence-based policy development in organ transplantation.

BACKGROUND/UNASSIGNED:Understanding center-level decision-making for suboptimal kidney (SOK) offers is critical to ensure utilization of all transplantable kidneys. METHODS/UNASSIGNED:We quantified center-level variation in accepting SOK deceased donor kidney transplant (DDKT) offers using 2021-2023 national registry data. SOK subtypes included: donor age >60, ultimate cold ischemia time >24 h, hepatitis C positive, terminal serum creatinine >2.0 mg/dL, donation after circulatory death, kidney donor profile index >85%, and public health service increased risk donors. Gini coefficient (Gini) was used to analyze inequality in DDKT utilization by SOK subtype. Multilevel logistic regression models were used to calculate the median odds ratio (mOR), measuring center-level variation in accepting SOK donor offers among adult centers. RESULTS/UNASSIGNED:Of all DDKTs, 72.6% were from donors with at least 1 SOK characteristic. Inequality persisted in utilization of SOK DDKTs (Gini of all SOKs: 0.53, Gini of all non-SOKs: 0.47). The 193 adult centers accepted a median (interquartile range) of 12.5% (8.4%-19.2%) offered non-SOK donors and 7.2% (4.6%-10.8%) offered SOK donors. Non-SOK donors and SOK donors were refused by a median (interquartile range) of 5 (3-10) and 9 (4-23) centers, respectively. The SOK subtypes with the least and the most center-level variance in acceptance were increased risk donor (mOR = 2.06) and cold ischemia time >36 h (mOR = 4.86), respectively. CONCLUSIONS/UNASSIGNED:Centers vary sharply in their willingness to accept certain types of SOK offers. Informing centers of their patterns of accepting specific donor phenotypes compared with their peers may motivate centers to accept more SOKs for clinically suitable recipients, thus improving patient access to DDKT.

INTRODUCTION/BACKGROUND:Following implementation of the U.S. Kidney Allocation System (KAS) in 2014, deceased donor kidneys with a kidney donor profile index (KDPI) < 35% are prioritized for allocation to pediatric candidates. Early post-KAS data suggested this prioritization may have led to more frequent delayed graft function compared to pre-KAS, when pediatric allocation priority was based on donor age < 35 years. We sought to understand the impact of this allocation change on longer-term pediatric kidney transplant outcomes. METHODS:We used SRTR data to identify all deceased donor kidney transplants with pediatric recipients during two eras: "Pre-KAS" (12/1/2009-11/30/2014) and "KAS" (12/1/2015-11/30/2020). We used Cox proportional hazards models to calculate the association between study era and all-cause graft failure (graft failure or death) after adjusting for recipient characteristics. RESULTS:, p = 0.001). Results were similar in sensitivity analyses limited to recipients < 10 years old and recipients alive with a functioning graft 90 days post-transplant. CONCLUSIONS:KDPI-based prioritization of kidneys for pediatric allocation was associated with a lower risk of graft failure compared to donor age-based prioritization. Further refining donor risk scores may enable additional improvements in graft survival.

BACKGROUND/UNASSIGNED:Kidney transplant recipients are at risk for adverse health outcomes. Digital health tools such as wearable accelerometers and continuous glucose monitors (CGMs) can provide detailed, noninvasive tracking of health behaviors and measures, such as physical activity, sleep, and glucose levels, that may offer insights into future health concerns, such as posttransplant diabetes mellitus, cognitive health, and transplant rejection. However, there is limited evidence on the feasibility and acceptability of these devices in kidney transplant candidates older than 50 y. METHODS/UNASSIGNED:This observational cross-sectional pilot study aimed to examine the feasibility of 2 digital health tools: an accelerometer and a continuous glucose monitor. Participants were eligible for the study if they were living donor kidney transplant candidates, aged 50 y or older, had no known cognitive impairments, and could provide informed consent. Participants were asked to wear a CGM and an accelerometer for up to 14 d before their kidney transplant surgery. Device feasibility was quantified by (1) the total time the devices were worn, and (2) the validated System Usability Scale survey administered after the devices were returned. RESULTS/UNASSIGNED:20 participants enrolled in the study (mean age 64 ± 9 y, 25% women, 40% with type 2 diabetes). The median number of days of accelerometer and CGM wear were 7 (interquartile range, 6-10) d and 7 (interquartile range, 7-10) d, respectively. Ninety percent of participants reported a favorable opinion of both devices. Participants wore the CGM 100% of the time and the accelerometer 90% of the time, indicating high adherence. CONCLUSIONS/UNASSIGNED:The use of digital devices was acceptable among kidney transplant candidates aged older than 50 y, paving the way for larger studies to identify early digital biomarkers of health outcomes in this high-risk population.

BACKGROUND:Kidney transplantation (KT) from donors with human immunodeficiency virus (HIV-1) to recipients with HIV (HIV D+/R+) is noninferior to KT from donors without HIV (HIV D-/R+) with regard to safety. However, there may be differences in posttransplant infections. METHODS:We performed a secondary analysis of the HOPE in Action KT Study (NCT02602262) comparing the time to first clinically relevant infection within 24 months posttransplantation in 99 HIV D+/R+ versus 99 HIV D-/R+. Secondary outcomes included incidence rates, infection-related death, and timing of clinically relevant infection, each stratified by donor HIV status. RESULTS:The cumulative incidence of a clinically relevant infection at 24 months posttransplantation was 73.8% (95% confidence interval [CI]: 63.1%-81.2%) for HIV D+/R+ versus 64.7% (95% CI: 53.0%-73.4%) for HIV D-/R+. Comparing time to first clinically relevant infection in HIV D+/R+ versus HIV D-/R+, the adjusted hazard ratio (aHR) was 1.44 (95% CI: 1.01-2.04) at 24 months posttransplantation; for infections associated with hospitalization, the aHR was not significantly higher (1.21 [95% CI: .78-1.86). There were no significant differences in the number of infections, death from infection, duration, or site of infection between HIV D+/R+ versus HIV D-/R+, though viral infections were numerically more common in HIV D+/R+ (40% vs 35%). CONCLUSIONS:Although there was a statistically significant association between receipt of a kidney from a donor with HIV and time to first clinically relevant infection in the 24 months posttransplantation, there were no differences in infections associated with hospitalization. These data are overall reassuring as this emerging practice expands into clinical care. Clinical Trials Registration. NCT02602262.

INTRODUCTION/BACKGROUND:Elevated concentrations of air pollutants in residential neighborhoods are associated with poorer survival, cognitive, and cardiovascular health among older adults. Older kidney transplant (KT) recipients may be more vulnerable due to chronic immunosuppression and age-related co-morbidities. Therefore, we quantified the associations between pollutant concentrations and post-KT outcomes among older recipients. METHODS:]) were obtained from the Center for Air, Climate and Energy Solutions, and matched by ZIP code and year of KT. We used shared frailty models (cluster = state) to estimate the adjusted hazard ratios (aHR) of mortality and death-censored graft failure (DCGF) and competing risk models with cluster-robust standard errors to estimate the adjusted subhazard ratios (aSHR) of dementia and stroke by pollutant concentrations. RESULTS:concentrations were associated with a 3% (aSHR = 1.03, 95% CI: 1.00-1.07) and 4% higher risk of stroke (aSHR = 1.04, 95% CI: 1.02-1.07), respectively. CONCLUSION/CONCLUSIONS:Residence in neighborhoods with high concentrations of ambient air pollutants can worsen patient and graft survival, as well as increase the risk of stroke among older KT recipients. Early screening and interventions targeting older recipients living in such neighborhoods may be crucial for preserving cognitive and cerebrovascular health, as well as improving longitudinal quality of life.

BACKGROUND:Sarcopenia and myosteatosis are indicators of abnormal body composition (BC). Computed tomography (CT) imaging has proven to be an accurate modality for BC quantification in kidney transplantation (KT). We tested whether pre-KT CT-based BC was associated with both all-cause graft loss (ACGL) and mortality among adult recipients from two centers (Johns Hopkins Hospital [JHH] and University Medical Center Groningen [UMCG]). METHODS:Patients who underwent a KT between 2003 and 2020 were followed for a median (interquartile range) follow-up of 6.4 (4.6-8.5) years at JHH and 6.3 (5.1-7.5) years at UMCG. Cox proportional hazard models were used to estimate the associations of BC with ACGL/ mortality. Fine and Gray regression analysis was performed to assess the association between BC and death-censored graft loss. Prior to KT, 49% of recipients had sarcopenia and 66% had myosteatosis. RESULTS:In total 608 patients were included from JHH (N= 294) and UMCG (N=314). Sarcopenia was not associated with post-KT outcomes. Myosteatosis was associated with a higher risk of ACGL (adjusted hazard ratio 1.78, 95%CI:1.08 - 2.93) and mortality (adjusted hazard ratio 2.35, 95%CI: 1.27 - 4.33) at JHH, but showed no significant association at UMCG after adjusting for confounders. Myosteatosis did not show a significant association with death-censored graft loss at both centers. CONCLUSION/CONCLUSIONS:Myosteatosis ascertained from existing CT scans could help identify recipients at higher risk for ACGL who may benefit most from prehabilitation.

BACKGROUND/UNASSIGNED:A potential long-term complication of living kidney donation in male donors is scrotal swelling on the same side as the nephrectomy, and some undergo surgery to relieve discomfort from the fluid collection. The long-term risk for this outcome attributable to donation is unknown. OBJECTIVE/UNASSIGNED:To evaluate long-term scrotal surgery rates after laparoscopic nephrectomy in male living kidney donors compared with nondonors. DESIGN/UNASSIGNED:Population-based cohort study (2002 to 2024). (ClinicalTrials.gov: NCT06716723). SETTING/UNASSIGNED:Linked administrative health care databases in Ontario, Canada. PARTICIPANTS/UNASSIGNED:898 male living kidney donors who had a laparoscopic nephrectomy were matched in a 1:10 ratio with 8980 male nondonors from the general population. The matching characteristics were age, date of cohort entry, rural residence, income, prior vasectomy, and prior inguinal hernia repair. Participants were followed for a median of 9 years, up to 22 years. MEASUREMENTS/UNASSIGNED:The primary outcome was hospitalization for surgery to address a unilateral scrotal fluid collection. RESULTS/UNASSIGNED:< 0.001). The median time from donation to scrotal surgery was 5.2 years (IQR, 3.3 to 8.4 years); more than 90% of the surgeries were hydrocelectomies and were performed under general anesthesia. Over 20 years, the cumulative incidence was 13.8% in donors versus 0.7% in nondonors. LIMITATION/UNASSIGNED:The precise causal mechanism remains unknown. CONCLUSION/UNASSIGNED:Laparoscopic nephrectomy is associated with a higher risk for subsequent scrotal surgery in male living kidney donors. PRIMARY FUNDING SOURCE/UNASSIGNED:Canadian Institutes of Health Research.

RATIONALE & OBJECTIVE/UNASSIGNED:exposure and mortality, overall and by race and ethnicity. STUDY DESIGN/UNASSIGNED:Cohort study (2003-2019). SETTING & PARTICIPANTS/UNASSIGNED:National registry for patients with kidney failure. EXPOSURES/UNASSIGNED:), segregation scores (Theil's H method), deprivation scores (American Community Survey), and built environment factors (medically underserved areas [MUA] and urbanicity) by patients' residential ZIP code at dialysis initiation. OUTCOME/UNASSIGNED:All-cause mortality. ANALYTICAL APPROACH/UNASSIGNED:and mortality, overall and stratified by race and ethnicity. RESULTS/UNASSIGNED:< 0.001]). LIMITATIONS/UNASSIGNED:may not reflect individual-level exposures. CONCLUSIONS/UNASSIGNED:and reduce related mortality.