Waitlist Registrants Research Articles

Majority Rules? Assessing Access to Kidney Transplantation in a Predominantly Hispanic Population.

Despite being the national's largest ethnic minority, Hispanic Americans have inferior kidney transplant opportunities. San Antonio, Texas is the largest US city with a majority Hispanic population. We assessed the impact of this unique ethnic milieu on waitlisting and transplant practices among Hispanic patients. We studied patients >18 years old listed at our center for a kidney-only transplant between 2003-2022. Timing of waitlisting, transplant rates and waitlist outcomes were compared between Hispanic and non-Hispanic White patients. We evaluated 11,895 patients, of whom 67% (n = 8,008) were Hispanic, and 20% (n = 2,341) were White. Preemptive listing was less frequent in Hispanic patients (18% vs 37%). One-third of listed Hispanic patients (37%) and half of White patients (50%) were transplanted, with living-donor kidney transplant performed in 59% (n = 1,755) and 77% (n = 898), respectively. Adjusting for age, sex, blood type, preemptive listing, immunologic sensitization, education, employment, and listing era, Hispanic patients remained less likely to receive a deceased-donor transplant (HR 0.82, 95% CI 0.71 - 0.95). On covariate adjustment, White patients were more likely to experience waitlist death or deterioration (HR 1.23, 95% CI 1.12 - 1.36). Although waitlist attrition was more favorable among Hispanic patients, waitlist registration was delayed and kidney transplants less frequent compared to White patients. These data demonstrate that majority status alone does not mitigate ethnic disparities in kidney transplantation, while underlining the critical need for ongoing efforts to address physician and patient attitudes relating to suitability of Hispanic patients for transplantation.

Variation in intention-to-treat survival by MELD subtypes: All models created for end-stage liver disease are not equal

Kidney dysfunction is a major determinant of prognosis in patients with decompensated cirrhosis awaiting transplantation. We hypothesized that for identical model for end-stage liver disease (MELD) scores at listing, outcomes before and after liver transplantation may vary if the predominant driver of the MELD score is serum creatinine (Cr) vs. serum bilirubin (Br) or international normalized ratio (INR). We evaluated all adult patients registered for liver transplantation (LT) between 2016-2020 and excluded patients receiving MELD exceptions or undergoing dual organ transplantation. Using K-Means clustering analysis, we classified each patient as MELD-Br, MELD-INR or MELD-Cr depending on the dominant variable for their MELD score. The primary outcome was intent-to-treat (ITT) survival, defined as survival within 1 year from listing with or without LT. MELD scores of LT waitlist registrants were clustered into three subtypes: MELD-Br (n= 13,658), MELD-INR (n= 13,809), and MELD-Cr (n= 12,412). One-year ITT survival rates were 78% (MELD-Br), 75% (MELD-INR), and 65% (MELD-Cr), p <0.01. ITT survival was lower for each MELD subtype for females compared to males (e.g. MELD-Cr: 63% females vs. 67% males, p<0.0001). The MELD-Cr subtype had the highest MELD at listing (MELD-Cr 23.4 vs. MELD-Br 19.2 vs. MELD-INR 21.0) and the largest decline in MELD over 3 months (23% vs. 12% vs. 21%). In adjusted analyses including MELD-Na, MELD-Cr was associated with higher waitlist mortality (hazard ratio 1.339, 95% CI 1.279-1.402) and lower LT rates (hazard ratio 0.688, 95% CI 0.664-0.713) compaed to the other subtypes. For equivalent listing practices, registrants with the MELD-Cr subtype have lower ITT survival. MELD subtype may serve as a more sophisticated variable for dynamic assessment of mortality risk and to guide organ allocation. The model for end-stage liver disease (MELD) score is an excellent predictor of waitlist mortality; however, our work highlights that the driver of a patient's MELD score matters and particularly those driven by elevated creatinine are associated with lower 1-year intent-to-treat survival. The 1-year intent-to-treat survival is also lower for women compared to men within the Cr-dominant subtype. These results are important for physicians and patients undergoing LT evaluation as creatinine may serve as a marker of prognosis and even if creatinine levels improve the prognosis remains poor, necessitating discussion about alternative pathways for transplant. Our work also highlights that the type of kidney injury matters, in that those with acute kidney injury were more likely to die or remain on the waitlist than those with chronic kidney disease within the creatinine-dominant subtype.

Burden of Portal Hypertension Complications Is Greater in Liver Transplant Wait-Listed Registrants with End-Stage Liver Disease and Type 2 Diabetes

Background and AimsImpact of type 2 diabetes mellitus (T2DM) in patients with end-stage liver disease (ESLD) awaiting liver transplantation (LT) remains poorly defined. The objective of the present study is to evaluate the relationship between T2DM and clinical outcomes among patients with LT waitlist registrants. We hypothesize that the presence of T2DM will be associated with worse clinical outcomes.Methods593 patients adult (age 18 years or older) who were registered for LT between 1/2010 and 1/2017 were included in this retrospective analysis. The impact of T2DM on liver-associated clinical events (LACE), survival, hospitalizations, need for renal replacement therapy, and likelihood of receiving LT were evaluated over a 12-month period. LACE was defined as variceal hemorrhage, hepatic encephalopathy, and ascites. Kaplan–Meier and Cox regression analysis were used to determine the association between T2DM and clinical outcomes.ResultsThe baseline prevalence of T2DM was 32% (n = 191) and patients with T2DM were more likely to have esophageal varices (61% vs. 47%, p = 0.002) and history of variceal hemorrhage (23% vs. 16%, p = 0.03). The presence of T2DM was associated with increased risk of incident ascites (HR 1.91, 95% CI 1.11, 3.28, p = 0.019). Patients with T2DM were more likely to require hospitalizations (56% vs. 49%, p = 0.06), hospitalized with portal hypertension-related complications (22% vs. 14%; p = 0.026), and require renal replacement therapy during their hospitalization. Patients with T2DM were less likely to receive a LT (37% vs. 45%; p = 0.03). Regarding MELD labs, patients with T2DM had significantly lower bilirubin at each follow-up; however, no differences in INR and creatinine were noted.ConclusionPatients with T2DM are at increased risk of clinical outcomes. This risk is not captured in MELD score, which may potentially negatively affect their likelihood of receiving LT.

Waitlisting and liver transplantation for MetALD in the United States: An analysis of the UNOS national registry.

The new steatotic liver disease (SLD) nomenclature introduced metabolic and alcohol-associated liver disease (MetALD), describing the intersection of metabolic dysfunction-associated steatotic liver disease (MASLD) and alcohol-associated liver disease (ALD). Waitlisting and liver transplantation for MetALD are not well-defined. We aimed to develop and validate an algorithm for identifying SLD phenotypes and assess trends in waitlisting and transplant outcomes. We conducted a retrospective cohort study using the United Network for Organ Sharing registry, supplemented with detailed single-center data. We developed five candidate algorithms for SLD classification and calculated their diagnostic performance. Trends in waitlist registrations and transplants were estimated, and competing risk analyses and Cox regression models were conducted to assess waitlist removal and post-transplant outcomes among SLD phenotypes. The best-performing algorithm demonstrated substantial agreement (weighted kappa, 0.62) for SLD phenotypes, with acceptable sensitivity (73%) for MetALD. Between 2002-2022, waitlist registrations and transplants for MetALD increased 2.9-fold and 3.3-fold. Since 2013, there was a significant increase in the absolute number of waitlist registrations (122 per year; 95% CI, 111-133) and transplants (107 per year; 95% CI, 94-120) for MetALD. Patients with MetALD experienced higher waitlist removal (aSHR, 1.10; 95% CI, 1.03-1.17), all-cause mortality (aHR, 1.13; 95%, 1.03-1.23), and graft failure (aHR, 1.12; 95% CI, 1.03-1.21) than those with ALD. We developed and validated an algorithm for identifying SLD phenotypes in UNOS. MetALD is the third leading etiology among those waitlisted and transplanted, exhibiting worse pre- and post-transplantation outcomes compared to ALD. Identifying and addressing factors determining poor outcomes is crucial in this patient population.

Revising model for end-stage liver disease from calendar-time cross-sections with correction for selection bias

BackgroundEurotransplant liver transplant candidates are prioritized by Model for End-stage Liver Disease (MELD), a 90-day waitlist survival risk score based on the INR, creatinine and bilirubin. Several studies revised the original MELD score, UNOS-MELD, with transplant candidate data by modelling 90-day waitlist mortality from waitlist registration, censoring patients at delisting or transplantation. This approach ignores biomarkers reported after registration, and ignores informative censoring by transplantation and delisting.MethodsWe study how MELD revision is affected by revision from calendar-time cross-sections and correction for informative censoring with inverse probability censoring weighting (IPCW). For this, we revised UNOS-MELD on patients with chronic liver cirrhosis on the Eurotransplant waitlist between 2007 and 2019 (n = 13,274) with Cox models with as endpoints 90-day survival (a) from registration and (b) from weekly drawn calendar-time cross-sections. We refer to the revised score from cross-section with IPCW as DynReMELD, and compare DynReMELD to UNOS-MELD and ReMELD, a prior revision of UNOS-MELD for Eurotransplant, in geographical validation.ResultsRevising MELD from calendar-time cross-sections leads to significantly different MELD coefficients. IPCW increases estimates of absolute 90-day waitlist mortality risks by approximately 10 percentage points. DynReMELD has improved discrimination over UNOS-MELD (delta c-index: 0.0040, p < 0.001) and ReMELD (delta c-index: 0.0015, p < 0.01), with differences comparable in magnitude to the addition of an extra biomarker to MELD (delta c-index: ± 0.0030).ConclusionCorrecting for selection bias by transplantation/delisting does not improve discrimination of revised MELD scores, but substantially increases estimated absolute 90-day mortality risks. Revision from cross-section uses waitlist data more efficiently, and improves discrimination compared to revision of MELD exclusively based on information available at listing.

Excess waitlist mortality among candidates for multivisceral liver-intestine transplant in acuity circle allocation

Candidates for multivisceral transplant (MVT) have experienced decreased access to transplant in recent years. Using Organ Procurement and Transplantation Network data, transplant and waiting list outcomes for MVT (ie, liver-intestine, liver-intestine-pancreas, and liver-intestine-kidney-pancreas) candidates listed between February 4, 2018, and February 3, 2022, were analyzed, including model for end-stage liver disease/pediatric end-stage liver disease and exception scores by era (before and after acuity circle [AC] implementation on February 4, 2020) and age group (pediatric and adult). Of 284 MVT waitlist registrations (45.6% pediatric), fewer had exception points at listing post-AC compared to pre-AC (10.0% vs 19.1%), and they were less likely to receive transplant (19.1% vs 35.9% at 90 days; 35.7% vs 57.2% at 1 year). Of 177 MVT recipients, exception points at transplant were more common post-AC compared to pre-AC (30.8% vs 20.2%). Postpolicy, adult MVT candidates were more likely to be removed due to death/too sick compared with liver-alone candidates (13.5% vs 5.6% at 90 days; 24.2% vs 9.8% at 1 year), whereas no excess waitlist mortality was observed among pediatric MVT candidates. Under current allocation policy, multivisceral candidates experience inferior waitlist outcomes compared with liver-alone candidates. Clarification of guidance around submission and approval of multivisceral exception requests may help improve their access to transplantation and achieve equity between multivisceral and liver-alone candidates on the liver transplant waiting list.

The impact of Medicaid expansion and travel distance on access to transplantation

Most transplant centers require candidates be insured before they can join the waitlist for a deceased donor organ. After the Affordable Care Act, many uninsured Americans gained improved access to Medicaid. I examine the effect of this increase in access to insurance and find that Medicaid expansions significantly increase Medicaid-insured waitlist registrations by 39% and deceased donor transplants received by 44%, but the increase in registrations is larger for candidates who live closer to a transplant center. Additionally I show that most of these registrations would have been privately insured otherwise but provide suggestive evidence that this is better explained by improved access to subsidized private coverage due to other ACA reforms than from candidates with private coverage before the ACA switching to Medicaid coverage after expansion. This suggests that although the ACA improved access to the transplantation system, access is still limited for candidates who live far from centers.

Safety of Macitentan for the Treatment of Portopulmonary Hypertension: Real-World Evidence from the Combined OPUS/OrPHeUS Studies.

Portopulmonary hypertension (PoPH) carries a worse prognosis than other forms of pulmonary arterial hypertension (PAH). Data regarding use of PAH-specific therapies in patients with PoPH are sparse as they are usually excluded from clinical trials. This analysis describes patient characteristics, treatment patterns, outcomes, and safety profiles in patients with PoPH newly initiating macitentan in the USA using the OPUS/OrPHeUS combined dataset. OPUS was a prospective, US, multicenter, observational drug registry (April 2014-June 2020); OrPHeUS was a retrospective, US, multicenter chart review (October 2013-March 2017). Additional information regarding patients' liver disease was retrospectively collected for patients with PoPH in OPUS. The OPUS/OrPHeUS dataset included 206 patients with PoPH (median age 58years; 52.4% female), with baseline cirrhosis and liver test abnormalities reported in 72.8% and 31.6% of patients respectively. Macitentan was initiated as combination therapy in 74.8% of patients and median (Q1, Q3) exposure to macitentan was 11.9 (3.1, 26.0) months. One-year Kaplan-Meier estimates (95% confidence limit, CL) of patients free from all-cause hospitalization and survival were 48.6% (40.7, 56.0) and 82.2% (75.1, 87.4). Of the 96 patients with PoPH in OPUS, 29.2% were classified as in need of liver transplant due to underlying liver disease during the study; transplant waitlist registration was precluded because of PAH severity for 32.1% and 17.9% were transplanted. Hepatic adverse events (HAE) were experienced by 49.0% of patients; the most common being increased bilirubin (16.0%), ascites (7.3%), and hepatic encephalopathy (5.8%); 1.5% and 21.8% of patients discontinued macitentan as a result of HAE and non-hepatic adverse events. There were no unexpected safety findings in patients with PoPH treated with macitentan. These data add to the evidence supporting the safety and tolerability of macitentan in patients with PoPH. A graphical abstract is available with this article. OPsumit® Users Registry (OPUS): NCT02126943; OPsumit® Historical Users cohort (OrPHeUS): NCT03197688; www. gov .

A2/A2B to B deceased donor kidney transplantation in the Kidney Allocation System era

Kidney transplantation from blood type A2/A2B donors to type B recipients (A2→B) has increased dramatically under the current Kidney Allocation System (KAS). Among living donor transplant recipients, A2-incompatible transplants are associated with an increased risk of all-cause and death-censored graft failure. In light of this, we used data from the Scientific Registry of Transplant Recipients from December 2014 until June 2022 to evaluate the association between A2→B listing and time to deceased donor kidney transplantation (DDKT) and post-DDKT outcomes for A2→B recipients. Among 53 409 type B waitlist registrants, only 12.6% were listed as eligible to accept A2→B offers ("A2-eligible"). The rates of DDKT at 1-, 3-, and 5-years were 32.1%, 61.4%, and 72.1% among A2-eligible candidates and 14.1%, 29.9%, and 44.1% among A2-ineligible candidates, with the former experiencing a 133% higher rate of DDKT (Cox weighted hazard ratio (wHR) = 2.192.332.47; P < .001). The 7-year adjusted mortality was comparable between A2→B and B-ABOc (type B/O donors to B recipients) recipients (wHR 0.780.941.13, P = .5). Moreover, there was no difference between A2→B vs B-ABOc DDKT recipients with regards to death-censored graft failure (wHR 0.771.001.29, P > .9) or all-cause graft loss (wHR 0.820.961.12, P = .6). Following its broader adoption since the implementation of the kidney allocation system, A2→B DDKT appears to be a safe and effective transplant modality for eligible candidates. As such, A2→B listing for eligible type B candidates should be expanded.

Association between neighborhood-based material deprivation and liver transplant waitlist registrants demographics and mortality.

Liver transplantation for alcohol-related liver disease (ARLD) has increased. We examined temporal trends in ARLD listing practices by neighborhood deprivation and evaluated the impact of neighborhood deprivation on waitlist mortality. We included all adults>18 years listed 2008-2019 in the UNOS registry. Our primary exposure was the neighborhood socioeconomic deprivation index based on patients' listing zip codes. We determined temporal trends in an ARLD listing diagnosis. We modeled ARLD listing diagnosis using logistic regression and waitlist mortality using Cox proportional hazards models. The waitlist contained an increasing proportion of patients listed with ARLD over the study period; however, this rate increased the least for patients from the most deprived tertile (p<.001). Patients from the most deprived tertile were the least likely to be listed with ARLD (OR: .97, 95CI: .95-.98). In our adjusted model, patients from the most deprived tertile had an increased hazard of waitlist mortality (OR: 1.10, 95CI: 1.06-1.14). Neighborhood deprivation was associated with a decreased likelihood of being listed with ARLD, suggesting that transplant for ARLD is inequitably available. The increased mortality associated with neighborhood deprivation demands future work to uncover the underlying reasons for this disparity.

Pediatric Nephrology Workforce in the United States and Access to Waitlist Registration in Children with ESKD

Pediatric Nephrology Workforce in the United States and Access to Waitlist Registration in Children with ESKD

Rurality of patient residence and access to transplantation among children with kidney failure in the United States.

Residence in rural areas is often a barrier to health care access. To date, differences in access to kidney transplantation among children who reside in rural and micropolitan areas of the US have not been explored. A retrospective cohort study of children < 18years who developed kidney failure between 2000 and 2019 according to the United States Renal Data System (USRDS). We examined the association between rurality of patient residence and time to living and/or deceased donor kidney transplantation (primary outcomes) and waitlist registration (secondary outcome) using Fine-Gray models. We included 18,530 children, of whom 14,175 (76.5%) received a kidney transplant (39.8% from a living and 60.2% from a deceased donor). Residence in micropolitan (subhazard ratio (SHR) 1.16; 95% CI 1.06-1.27) and rural (SHR 1.18; 95% CI 1.06-1.3) areas was associated with better access to living donor transplantation compared with residence in metropolitan areas. There was no statistically significant association between residence in micropolitan (SHR, 0.95; 95%CI 0.88-1.03) and rural (SHR, 0.94; 95%CI 0.86-1.03) areas compared with metropolitan areas in the access of children to deceased donor transplantation. There was also no difference in the time to waitlist registration comparing micropolitan (SHR 1.04; 95%CI 0.98-1.10) and rural (SHR 1.05; 95% CI 0.98-1.13) versus metropolitan areas. In children with kidney failure, residence in rural and micropolitan areas was associated with better access to living donor transplantation and similar access to deceased donor transplantation compared with residence in metropolitan areas.

Liver transplantation access and outcomes: Impact of variations in liver-specific specialty care

BackgroundWe sought to characterize the impact access to gastroenterologists/hepatologists has on liver transplantation listing, as well as time on the liver transplantation waitlist and post-transplant outcomes. MethodsLiver transplantation registrants aged >18 years between January 1, 2004 and December 31, 2019 were identified from the Scientific Registry of Transplant Recipients Standard Analytic Files. The liver transplantation registration ratio was defined as the ratio of liver transplant waitlist registrations in a given county per 1,000 liver-related deaths. ResultsA total of 150,679 liver transplantation registrants were included. Access to liver transplantation centers and liver-specific specialty physicians varied markedly throughout the United States. Of note, the liver transplantation registration ratio was lower in counties with poor access to liver-specific care versus counties with adequate access (poor access 137.2, interquartile range 117.8–163.2 vs adequate access 157.6, interquartile range 127.3–192.2, P < .001). Among patients referred for liver transplantation, the cumulative incidence of waitlist mortality and post-transplant graft survival was comparable among patients with poor versus adequate access to liver-specific care (both P > .05). Among liver transplantation recipients living in areas with poor access, after controlling for recipient and donor characteristics, cold ischemic time, and model for end-stage liver disease score, the area deprivation index predicted graft survival (referent, low area deprivation index; medium area deprivation index, hazard ratio 1.52, 95% confidence interval 1.03–12.23; high area deprivation index, 1.45, 95% confidence interval 1.01–12.09, both P < .05). ConclusionPoor access to liver-specific care was associated with a reduction in liver transplantation registration, and individuals residing in counties with high social deprivation had worse graft survival among patients living in counties with poor access to liver-specific care.

Travel distance and social vulnerability index: Impact on liver-related mortality among patients with end-stage liver disease.

The reasons for the geographic disparities in liver-related mortality across the US remain ill-defined. We sought to investigate the impact of travel distance to liver transplantation (LT) programs and social vulnerability on county differences in liver-related mortality. Data on LT registrants were obtained from the Scientific Registry of Transplant Recipients Standard Analytic Files (SRTR SAFs) between 2004 and 2019. Liver-related mortality data were obtained from the Center for Disease Control and Prevention's Wide-ranging Online Data for Epidemiologic Research (CDC WONDER) platform. Spatial epidemiological clustering of county-level LT registration and liver-related mortality rates was determined using local Moran's I. Comparison analyses assessed social vulnerability index (SVI) and travel distance within various county clusters. Among 151864 LT waitlist registrants who were diagnosed with liver disease due to hepatitis C virus (HCV) or hepatitis B virus (HBV) (n=68479, 45.1%), alcohol (n=38328, 25.2%), non-alcoholic steatohepatitis (NASH) (n=17485, 11.5%), liver tumors (n=16644, 11.0%), and other diseases (n = 10928, 7.2%), median SVI was 59.3 (IQR, 40.1-83.4). SVI (76.2 vs. 24.3, p<.001) was greater in the highest versus lowest liver-related mortality quartiles. The travel distances to LT centers (143.1 miles vs. 107.2 miles, p<.001) was longer in the lowest versus highest LT registration quartiles. Counties with low LT registration rates and high liver-related mortality rates were associated with long travel distances and high SVI. In contrast, while counties with high LT registration rates and high liver-related mortality rates had comparable SVI, travel distance was relatively shorter. Counties with greater SVIs were associated with higher liver-related mortality, with the highest SVI counties having the highest overall liver-related mortality. Longer travel distances were associated with higher liver-related mortality. These findings highlight the impact of social determinants of health (SDOH) on liver disease outcomes.

Decreased Utilization Rate of Grafts for Liver Transplantation After Implementation of Acuity Circle-based Allocation.

The allocation system for livers began using acuity circles (AC) in 2020. In this study, we sought to evaluate the impact of AC policy on the utilization rate for liver transplantation (LT). Using the US national registry data between 2018 and 2022, LTs were equally divided into 2 eras: pre-AC (before February 4, 2020) and post-AC (February 4, 2020, and after). Deceased potential liver donors were defined as deceased donors from whom at least 1 organ was procured. The annual number of deceased potential liver donors increased post-AC (from 10 423 to 12 259), approaching equal to that of new waitlist registrations for LT (n = 12 801). Although the discard risk index of liver grafts was comparable between the pre- and post-AC eras, liver utilization rates in donation after brain death (DBD) and donation after circulatory death (DCD) donors were lower post-AC ( P < 0.01; 79.8% versus 83.4% and 23.7% versus 26.0%, respectively). Recipient factors, ie, no recipient located, recipient determined unsuitable, or time constraints, were more likely to be reasons for nonutilization after implementation of the AC allocation system compared to the pre-AC era (20.0% versus 12.3% for DBD donors and 50.1% versus 40.8% for DCD donors). Among non-high-volume centers, centers with lower utilization of marginal DBD donors or DCD donors were more likely to decrease LT volume post-AC. Although the number of deceased potential liver donors has increased, overall liver utilization among deceased donors has decreased in the post-AC era. To maximize the donor pool for LT, future efforts should target specific reasons for liver nonutilization.

Poor functional status at the time of waitlist for pediatric lung transplant is associated with worse pretransplant outcomes

Whether functional status is associated with survival to pediatric lung transplant is unknown. We hypothesized that completely dependent functional status at waitlist registration, defined using Lansky Play Performance Scale (LPPS), would be associated with worse outcomes. Retrospective cohort study of pediatric lung transplant registrants utilizing United Network for Organ Sharing's Standard Transplant Analysis and Research files (2005-2020). Primary exposure was completely dependent functional status, defined as LPPS score of 10-40. Primary outcome was waitlist removal for death/deterioration with cause-specific hazard ratio (CSHR) regression. Subdistribution hazard regression (SHR, Fine and Gray) was used for the secondary outcome of waitlist removal due to transplant/improvement with a competing risk of death/deterioration. Confounders included: sex, age, race, diagnosis, ventilator dependence, extracorporeal membrane oxygenation, year, and listing center volume. A total of 964 patients were included (63.5% ≥ 12 years, 50.2% cystic fibrosis [CF]). Median waitlist days were 95; 20.1% were removed for death/deterioration and 68.2% for transplant/improvement. Completely dependent functional status was associated with removal due to death/deterioration (adjusted CSHR 5.30 [95% CI 2.86-9.80]). This association was modified by age (interaction p=0.0102), with a larger effect for age ≥12 years, and particularly strong for CF. In the Fine and Gray model, completely dependent functional status did not affect the risk of removal due to transplant/improvement with a competing risk of death/deterioration (adjusted SHR 1.08 [95% CI 0.77-1.49]). Pediatric lung transplant registrants with the worst functional status had worse pretransplant outcomes, especially for adolescents and CF patients. Functional status at waitlist registration may be a modifiable risk factor to improve survival to lung transplant.

Natural history of NASH cirrhosis in liver transplant waitlist registrants

Non-alcoholic steatohepatitis (NASH) cirrhosis is rapidly growing as an indication for liver transplant(ation) (LT). However, the natural history of NASH cirrhosis among LT waitlist registrants has not been established. The present study aimed to define the natural history of NASH cirrhosis using the Scientific Registry of Transplant Recipients database. The study cohort comprised patients registered on the LT waitlist between 1/1/2016 to 12/31/2021. The primary outcomes included probability of LT and waitlist mortality, comparing NASH (n= 8,120) vs. non-NASH (n= 21,409) cirrhosis. Patients with NASH cirrhosis were listed with lower model for end-stage liver disease (MELD) scores despite bearing a greater burden of portal hypertension, especially at lower MELD scores. The overall transplant probability in LT waitlist registrants with NASH [vs. non-NASH] cirrhosis was significantly lower at 90 days (HR 0.873, p <0.001) and 1 year (HR 0.867, p <0.001); this was even more pronounced in patients with MELD scores >30 (HR 0.705at 90 days and HR 0.672at 1 year, p <0.001 for both). Serum creatinine was the key contributor to MELD score increases leading to LT among LT waitlist registrants with NASH cirrhosis, while bilirubin was in patients with non-NASH cirrhosis. Finally, waitlist mortality at 90 days (HR 1.15, p <0.001) and 1 year (1.25, p <0.001) was significantly higher in patients with NASH cirrhosis compared to those with non-NASH cirrhosis. These differences were more pronounced in patients with lower MELD scores at the time of LT waitlist registration. LT waitlist registrants with NASH cirrhosis are less likely to receive a transplant compared to patients with non-NASH cirrhosis. Serum creatinine was the major contributor to MELD score increases leading to LT in patients with NASH cirrhosis. This study provides important insights into the distinct natural history of non-alcoholic steatohepatitis (NASH) cirrhosis among liver transplant (LT) waitlist registrants, revealing that patients with NASH cirrhosis face lower odds of transplantation and higher waitlist mortality than those with non-NASH cirrhosis. Our study underscores the significance of serum creatinine as a crucial contributor to model for end-stage liver disease (MELD) score in patients with NASH cirrhosis. These findings have substantial implications, emphasizing the need for ongoing evaluation and refinement of the MELD score to more accurately capture mortality risk in patients with NASH cirrhosis on the LT waitlist. Moreover, the study highlights the importance of further research investigating the impact of the implementation of MELD 3.0 across the US on the natural history of NASH cirrhosis.

Predicting a kidney transplant patient’s pre-transplant functional status based on information from waitlist registration

With over 100,000 patients on the kidney transplant waitlist in 2019, it is important to understand if and how the functional status of a patient may change while on the waitlist. Recorded both at registration and just prior to transplantation, the Karnofsky Performance Score measures a patient’s functional status and takes on values ranging from 0 to 100 in increments of 10. Using machine learning techniques, we built a gradient boosting regression model to predict a patient’s pre-transplant functional status based on information known at the time of waitlist registration. The model’s predictions result in an average root mean squared error of 12.99 based on 5 rolling origin cross validations and 12.94 in a separate out-of-time test. In comparison, predicting that the pre-transplant functional status remains the same as the status at registration, results in average root mean squared errors of 14.50 and 14.11 respectively. The analysis is based on 118,401 transplant records from 2007 to 2019. To the best of our knowledge, there has been no previously published research on building a model to predict kidney pre-transplant functional status. We also find that functional status at registration and total serum albumin, have the most impact in predicting the pre-transplant functional status.

Sex disparity in dialysis and kidney transplantation over 20 years in Korea.

Sex disparity is prevalent in organ transplantations worldwide. This study aimed to understand sex disparities in dialysis and kidney transplantation in Korea over the last 20 years. Data for incident dialysis, waiting list registration, and donors and recipients were retrospectively collected between January 2000 and December 2020 from the Korean Society of Nephrology end-stage renal disease registry and the database of the Korean Network for Organ Sharing. Data regarding the proportion of females for dialysis, waiting list, and kidney transplantation donors or recipients were analyzed using linear regression analysis. The average proportion of females on dialysis over the past 20 years was 40.5%. The proportion of females on dialysis was 42.8% in 2000, and decreased to 38.2% in 2020, showing a decreasing trend. The average proportion of women on the waiting list was 38.4%, which was lower than that for dialysis. The average proportion of female recipients in living donor kidney transplantation and female living donors were 40.1% and 53.2%, respectively. The overall proportion of female donors in living donor kidney transplantation showed an increasing trend. However, there was no change in the proportion of female recipients in living donor kidney transplantation. Sex disparities in organ transplantation exist, including an increasing trend of female donors in living donor kidney transplantation. Further studies are needed to identify the biological and socioeconomic factors involved to resolve these disparities.

MELD 3.0 for adolescent liver transplant candidates.

Adolescents constitute a unique waitlist cohort that is distinct from younger children. Model for End-stage Liver Disease (MELD) 3.0, which was developed in an adult population of liver transplant candidates, is planned to replace MELD-Sodium in the current liver allocation system for both adults and adolescents aged 12-17. We evaluated the predictive performance of MELD-Sodium, MELD 3.0, and Pediatric End-stage Liver Disease for 90-day waitlist mortality risk among adolescent liver transplant registrants. New waitlist registrations for primary liver transplants among individuals aged 12-17 and 18-25 for comparison were identified using Organ Procurement and Transplantation Network (OPTN) data from November 17, 2004, to December 31, 2021. The predictive performance of the current and proposed MELD and Pediatric End-stage Liver Disease scores was assessed using Harrell's concordance ( c ) statistic. There were 1238 eligible listings for adolescents aged 12-17 and 1740 young adults aged 18-25. In the adolescent group, 90-day survival was 97.8%, compared with 95.9% in those aged 18-25 (log-rank p = 0.005), with no significant differences when stratified by sex or indication. Among adolescents, increasing MELD 3.0 was associated with an increased hazard of mortality (HR=1.27, 95% CI: 1.18-1.37), and the c -statistic for 90-day waitlist survival using MELD 3.0 was 0.893 compared with 0.871 using MELD-Sodium and 0.852 using Pediatric End-stage Liver Disease. The discriminative ability of MELD 3.0 to rank adolescents according to the risk of death within 90 days was robust. Although MELD 3.0 was initially developed and validated in adults, MELD 3.0 may also improve the prediction of waitlist mortality in adolescents and better represent their urgency for liver transplants.