Dual-Organ Transplantation: Indications, Evaluation, and Outcomes for Heart-Kidney and Heart-Liver Transplantation: A Scientific Statement From the American Heart Association.

Although heart transplantation is the preferred therapy for appropriate patients with advanced heart failure, the presence of concomitant renal or hepatic dysfunction can pose a barrier to isolated heart transplantation. Because donor organ supply limits the availability of organ transplantation, appropriate allocation of this scarce resource is essential; thus, clear guidance for simultaneous heart-kidney transplantation and simultaneous heart-liver transplantation is urgently required. The purposes of this scientific statement are (1) to describe the impact of pretransplantation renal and hepatic dysfunction on posttransplantation outcomes; (2) to discuss the assessment of pretransplantation renal and hepatic dysfunction; (3) to provide an approach to patient selection for simultaneous heart-kidney transplantation and simultaneous heart-liver transplantation and posttransplantation management; and (4) to explore the ethics of multiorgan transplantation.

Anti-spike antibody durability after SARS-CoV-2 vaccination in adolescent solid organ transplant recipients.

BACKGROUND: Adolescent solid organ transplant recipients (aSOTRs) who received three doses of the COVID-19 mRNA vaccine experience high seroconversion rates and antibody persistence for up to 3 months. Long-term antibody durability beyond this timeframe following three doses of the SARS-CoV-2 mRNA vaccine remains unknown. We describe antibody responses 6 months following the third vaccine dose (D3) of the BNT162b2 mRNA vaccination among aSOTRs. METHODS: Participants in a multi-center, observational cohort who received the third dose of the vaccine were analyzed for antibodies to the SARS-CoV-2 spike protein receptor-binding domain (Roche Elecsys anti-SARS-CoV-2-S positive: ≥0.8, maximum: >2500 U/mL). Samples were collected at 1-, 3-, and 6-months post-D3. Participants were surveyed at each timepoint and at 12-months post-D3. RESULTS: All 34 participants had positive anti-RBD antibody titers 6 months post-D3. Variations in titers occurred between 3 and 6 months post-D3, with 8/28 (29%) having decreased antibody levels at 6 months compared to 3 months and 2/28 (7%) reporting increased titers at 6 months. The remaining 18/28 (64%) had unchanged antibody titers compared to 3-month post-D3 levels. A total of 4/34 (12%) reported breakthrough infection within 6 months and 3/32 (9%) reported infection after 6-12 months following the third dose of the SARS-CoV-2 mRNA vaccine. CONCLUSIONS: The results suggest that antibody durability persists up to 6 months following three doses of the SARS-CoV-2 mRNA in aSOTRs. Demography and transplant characteristics did not differ for those who experienced antibody weaning. Breakthrough infections did occur, reflecting immune-evasive nature of novel variants such as Omicron.

Impact of Seasonal Coronavirus Antibodies on Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine Responses in Solid Organ Transplant Recipients.

Antibody responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination are reduced in solid organ transplant recipients (SOTRs). We report that increased levels of preexisting antibodies to seasonal coronaviruses are associated with decreased antibody response to SARS-CoV-2 vaccination in SOTRs, supporting that antigenic imprinting modulates vaccine responses in SOTRs.

Characterizing the risk of human leukocyte antigen-incompatible living donor kidney transplantation in older recipients.

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: 1.632.072.65, P < .001), lower DCGF (hazard ratio: 0.360.530.77, P = .001), and AR (odds ratio: 0.390.540.74, P < .001), and similar DGF (odds ratio: 0.461.032.33, P = .9) and LOS (incidence rate ratio: 0.880.981.10, 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.

Critical interactions between race and the highly granular area deprivation index in liver transplant evaluation.

Neighborhood socioeconomic deprivation may have important implications on disparities in liver transplant (LT) evaluation. In this retrospective cohort study, we constructed a novel dataset by linking individual patient-level data with the highly granular Area Deprivation Index (ADI), which is advantageous over other neighborhood measures due to: specificity of Census Block-Group (versus Census Tract, Zip code), scoring, and robust variables. Our cohort included 1377 adults referred to our center for LT evaluation 8/1/2016-12/31/2019. Using modified Poisson regression, we tested for effect measure modification of the association between neighborhood socioeconomic status (nSES) and LT evaluation outcomes (listing, initiating evaluation, and death) by race and ethnicity. Compared to patients with high nSES, those with low nSES were at higher risk of not being listed (aRR = 1.14; 95%CI 1.05-1.22; p < .001), of not initiating evaluation post-referral (aRR = 1.20; 95%CI 1.01-1.42; p = .03) and of dying without initiating evaluation (aRR = 1.55; 95%CI 1.09-2.2; p = .01). While White patients with low nSES had similar rates of listing compared to White patients with high nSES (aRR = 1.06; 95%CI .96-1.17; p = .25), Underrepresented patients from neighborhoods with low nSES incurred 31% higher risk of not being listed compared to Underrepresented patients from neighborhoods with high nSES (aRR = 1.31; 95%CI 1.12-1.5; p < .001). Interventions addressing neighborhood deprivation may not only benefit patients with low nSES but may address racial and ethnic inequities.

The unfinished journey toward transplant equity: an analysis of racial/ethnic disparities for children after the implementation of the Kidney Allocation System in 2014.

BACKGROUND: Disparities in pediatric kidney transplantation (KT) result in reduced access and worse outcomes for minority children. We assessed the impact of recent systems changes on these disparities. METHODS: This is a retrospective cohort study of pediatric patients utilizing data from the US Renal Data System (n = 7547) and Scientific Registry of Transplant Recipients (n = 6567 waitlisted and n = 6848 transplanted patients). We compared access to transplantation, time to deceased donor kidney transplant (DDKT), and allograft failure (ACGF) in the 5 years preceding implementation of the Kidney Allocation System (KAS) to the 5 years post-KAS implementation 2010-2014 vs. 2015-2019, respectively. RESULTS: Compared to the pre-KAS era, post-KAS candidates were more likely to be pre-emptively listed (26.8% vs. 38.1%, p < 0.001), pre-emptively transplanted (23.8% vs. 28.0%, p < 0.001), and less likely to have private insurance (35.6% vs. 32.3%, p = 0.01), but these were not uniform across racial groups. Compared to white children, Black and Hispanic children had a lower likelihood of transplant listing within 2 years of first dialysis service (aHR 0.590.670.76 and 0.730.820.92, respectively) in the post-KAS era. Time to DDKT was comparable across all racial groups in the post-KAS era. Compared to white children, Black DDKT recipients have more 5-year ACGF (aHR 1.001.432.06 p = 0.05) while there was no difference in 3- or 5-year ACGF among LDKT recipients. CONCLUSIONS: After KAS implementation, there is equity in time to DDKT. Pre-KAS increased hazard of ACGF among Black children has decreased in the post-KAS era; however, persistent disparities exist in time to transplant listing among Black and Hispanic children when compared to white children. A higher resolution version of the Graphical abstract is available as Supplementary information.

Heterologous Ad.26.COV2.S versus homologous BNT162b2/mRNA-1273 as a third dose in solid organ transplant recipients seronegative after two-dose mRNA vaccination.

Heterologous vaccination ("mixing platforms") for the third (D3) dose of SARS-CoV-2 vaccine is a potential strategy to improve antibody responses in solid organ transplant recipients (SOTRs), but data are mixed regarding potential differential immunogenicity. We assessed for differences in immunogenicity and tolerability of homologous (BNT162b2 or mRNA-1273; D3-mRNA) versus heterologous (Ad.26.COV2.S; D3-JJ) D3 among 377 SARS-CoV-2-infection naïve SOTRs who remained seronegative after two mRNA vaccines. We measured anti-spike titers and used weighted Poisson regression to evaluate seroconversion and development of high-titers, comparing D3-JJ to D3-mRNA, at 1-, 3-, and 6 month post-D3. 1-month post-D3, seroconversion (63% vs. 52%, p = .3) and development of high-titers (29% vs. 25%, p = .7) were comparable between D3-JJ and D3-mRNA recipients. 3 month post-D3, D3-JJ recipients were 1.4-fold more likely to seroconvert (80% vs. 57%, weighted incidence-rate-ratio: wIRR = 1.10 1.401.77 , p = .006) but not more likely to develop high-titers (27% vs. 22%, wIRR = 0.44 0.921.93 , p = .8). 6 month post-D3, D3-JJ recipients were 1.41-fold more likely to seroconvert (88% vs. 59%, wIRR = 1.04 1.411.93 , p = .029) and 2.63-fold more likely to develop high-titers (59% vs. 21%, wIRR = 1.38 2.635.00 , p = .003). There was no differential signal in alloimmune events or reactogenicity between platforms. SOTRs without antibody response after two mRNA vaccines may derive benefit from heterologous Ad.26.COV2.S D3.

A third dose of SARS-CoV-2 vaccine increases neutralizing antibodies against variants of concern in solid organ transplant recipients.

Vaccine-induced SARS-CoV-2 antibody responses are attenuated in solid organ transplant recipients (SOTRs) and breakthrough infections are more common. Additional SARS-CoV-2 vaccine doses increase anti-spike IgG in some SOTRs, but it is uncertain whether neutralization of variants of concern (VOCs) is enhanced. We tested 47 SOTRs for clinical and research anti-spike IgG, pseudoneutralization (ACE2 blocking), and live-virus neutralization (nAb) against VOCs before and after a third SARS-CoV-2 vaccine dose (70% mRNA, 30% Ad26.COV2.S) with comparison to 15 healthy controls after two mRNA vaccine doses. We used correlation analysis to compare anti-spike IgG assays and focused on thresholds associated with neutralization. A third SARS-CoV-2 vaccine dose increased median total anti-spike (1.6-fold), pseudoneutralization against VOCs (2.5-fold vs. Delta), and neutralizing antibodies (1.4-fold against Delta). However, neutralization activity was significantly lower than healthy controls (p < .001); 32% of SOTRs had zero detectable nAb against Delta after third vaccination compared to 100% for controls. Correlation with nAb was seen at anti-spike IgG >4 Log10 (AU/ml) on the Euroimmun ELISA and >4 Log10 (AU/ml) on the MSD research assay. These findings highlight benefits of a third vaccine dose for some SOTRs and the need for alternative strategies to improve protection in a significant subset of this population.

Offer Acceptance Patterns for Liver Donors Aged 70 and Older.

Despite a documented survival benefit, older liver donor (OLD, age ≥70) graft offers are frequently declined, with utilization worsening over the last decade. To understand how offer acceptance varies by center, we studied 1113 eventually transplanted OLD grafts from 2009 to 2017 using Scientific Registry of Transplant Recipients (SRTR) data and random-intercept multilevel logistic regression. To understand how center-level acceptance of OLD graft offers might be associated with waitlist and posttransplant outcomes, we studied all adult, actively listed, liver-only candidates and recipients during the study period using Poisson regression (transplant rate), competing risks regression (waitlist mortality), and Cox regression (posttransplant mortality). Among 117 centers, OLD offer acceptance ranged from 0 (23 centers) to 95 acceptances, with a median odds ratio of 2.88. Thus, a candidate may be three times as likely to receive an OLD graft simply by listing at a different center. Centers in the highest quartile (Q4) of OLD acceptance (accepted 39% of OLD offers) accepted more nationally shared organs (Q4 versus Q1: 14.1% versus 0.0%, P < 0.001) and had higher annual liver transplant volume (Q4 versus Q1: 80 versus 21, P < 0.001). After adjustment, nationally shared OLD offers (adjusted odds ratio [aOR]: 0.16, 95% confidence interval [CI]: 0.13-0.20) and offers to centers with higher median Model for End-Stage Liver Disease (MELD) at transplant (aOR: 0.74, 95% CI: 0.62-0.87) were less likely to be accepted. OLD offers to centers with higher annual transplant volume were more likely to be accepted (aOR: 1.21, 95% CI: 1.14-1.30). Additionally, candidates listed at centers within the highest quartile of OLD graft offer acceptance had higher deceased donor liver transplantation (DDLT) rates (adjusted incidence rate ratio: 1.45, 95% CI: 1.41-1.50), lower waitlist mortality (adjusted subhazard ratio: 0.76, 95% CI: 0.72-0.76), and similar posttransplant survival (adjusted hazard ratio: 0.93, 95% CI: 0.86-1.01) when compared with those listed at centers in the lowest quartile of OLD graft offer acceptance. The wide variation in OLD offer acceptance supports the need for optimizing the organ offer process and efficiently directing OLD offers to centers more likely to use them.

Noninvasive Risk Stratification for Nonalcoholic Fatty Liver Disease Among Living Liver Donor Candidates: A Proposed Algorithm.

To reduce waitlist mortality, living donor liver transplantation (LDLT) has increased over the past decade in the United States, but not at a rate sufficient to completely mitigate organ shortage. As a result, there are ongoing efforts to expand the living liver donor pool. Simultaneously, the prevalence of nonalcoholic fatty liver disease (NAFLD) in the general population has increased, which has significant implications on the pool of potential living liver donors. As such, a clinical assessment algorithm that exhaustively evaluates for NAFLD and fibrosis is critical to the safe expansion of LDLT. An ideal algorithm would employ safe and noninvasive methods, relying on liver biopsy only when necessary. While exclusion of NAFLD and fibrosis by noninvasive means is widely studied within the general population, there are no well-accepted guidelines for evaluation of living donors using these modalities. Here we review the current literature regarding noninvasive NALFD and fibrosis evaluation and propose a potential algorithm to apply these modalities for the selection of living liver donors.

Multicenter study of racial and ethnic inequities in liver transplantation evaluation: Understanding mechanisms and identifying solutions.

Racial and ethnic disparities persist in access to the liver transplantation (LT) waiting list; however, there is limited knowledge about underlying system-level factors that may be responsible for these disparities. Given the complex nature of LT candidate evaluation, a human factors and systems engineering approach may provide insights. We recruited participants from the LT teams (coordinators, advanced practice providers, physicians, social workers, dieticians, pharmacists, leadership) at two major LT centers. From December 2020 to July 2021, we performed ethnographic observations (participant-patient appointments, committee meetings) and semistructured interviews (N = 54 interviews, 49 observation hours). Based on findings from this multicenter, multimethod qualitative study combined with the Systems Engineering Initiative for Patient Safety 2.0 (a human factors and systems engineering model for health care), we created a conceptual framework describing how transplant work system characteristics and other external factors may improve equity in the LT evaluation process. Participant perceptions about listing disparities described external factors (e.g., structural racism, ambiguous national guidelines, national quality metrics) that permeate the LT evaluation process. Mechanisms identified included minimal transplant team diversity, implicit bias, and interpersonal racism. A lack of resources was a common theme, such as social workers, transportation assistance, non-English-language materials, and time (e.g., more time for education for patients with health literacy concerns). Because of the minimal data collection or center feedback about disparities, participants felt uncomfortable with and unadaptable to unwanted outcomes, which perpetuate disparities. We proposed transplant center-level solutions (i.e., including but not limited to training of staff on health equity) to modifiable barriers in the clinical work system that could help patient navigation, reduce disparities, and improve access to care. Our findings call for an urgent need for transplant centers, national societies, and policy makers to focus efforts on improving equity (tailored, patient-centered resources) using the science of human factors and systems engineering.

Analysis of individual components of frailty: Pre-transplant grip strength is the strongest predictor of post kidney transplant outcomes.

Frailty is commonly assessed during kidney transplant recipient (KTR) evaluation. However, individual frailty components may have varying impact on post-transplant outcomes. In this single-center study of 825 KTRs, we determined the association between the individual components of a modified Fried frailty score and delayed graft function (DGF), early hospital readmission (EHR), cardiovascular (CV) events, acute rejection (AR), death censored graft failure (DCGF), and death. Sum frailty ≥3 was significantly associated with EHR (aOR = 3.62; 95% CI: 1.21-10.80). Among individual components, only grip strength was significantly associated with EHR (aOR = 1.54; 95% CI: 1.03-2.31). The addition of grip strength to a model with the other four components resulted in Net Reclassification Improvement (NRI) of 20.51% (p = .01). Similarly, only grip strength was significantly associated with CV events (aOR = 1.79; 95% CI: 1.12-2.86). The addition of grip strength to a model with the other four components resulted in NRI of 27.37% (p = .006). No other frailty components were associated with the outcomes of interest. Based on our findings, handgrip strength may be an important tool while assessing frailty, mainly predicting early readmission and cardiovascular events post-transplant.

Ambient air pollution and posttransplant outcomes among kidney transplant recipients.

Fine particulate matter (PM2.5 ), a common form of air pollution which can induce systemic inflammatory response, is a risk factor for adverse health outcomes. Kidney transplant (KT) recipients are likely vulnerable to PM2.5 due to comorbidity and chronic immunosuppression. We sought to quantify the association between PM2.5 and post-KT outcomes. For adult KT recipients (1/1/2010-12/31/2016) in the Scientific Registry of Transplant Recipients, we estimated annual zip-code level PM2.5 concentrations at the time of KT using NASA's SEDAC Global PM2.5 Grids. We determined the associations between PM2.5 and delayed graft function (DGF) and 1-year acute rejection using logistic regression and death-censored graft failure (DCGF) and mortality using Cox proportional hazard models. All models were adjusted for sociodemographics, recipient, transplant, and ZIP code level confounders. Among 87 233 KT recipients, PM2.5 was associated with increased odds of DGF (OR = 1.59; 95% CI: 1.48-1.71) and 1-year acute rejection (OR = 1.31; 95% CI: 1.17-1.46) and increased risk of all-cause mortality (HR = 1.15; 95% CI: 1.07-1.23) but not DCGF (HR = 1.05; 95% CI: 0.97-1.51). In conclusion, PM2.5 was associated with higher odds of DGF and 1-year acute rejection and elevated risk of mortality among KT recipients. Our study highlights the importance of considering environmental exposure as risk factors for post-KT outcomes.

Characterizing the landscape and impact of infections following kidney transplantation.

Infections remain a major threat to successful kidney transplantation (KT). To characterize the landscape and impact of post-KT infections in the modern era, we used United States Renal Data System (USRDS) data linked to the Scientific Registry of Transplant Recipients (SRTR) to study 141 661 Medicare-primary kidney transplant recipients from January 1, 1999 to December 31, 2014. Infection diagnoses were ascertained by International Classification of Diseases, Ninth Revision (ICD-9) codes. The cumulative incidence of a post-KT infection was 36.9% at 3 months, 53.7% at 1 year, and 78.0% at 5 years. The most common infections were urinary tract infection (UTI; 46.8%) and pneumonia (28.2%). Five-year mortality for kidney transplant recipients who developed an infection was 24.9% vs 7.9% for those who did not, and 5-year death-censored graft failure (DCGF) was 20.6% vs 10.1% (P < .001). This translated to a 2.22-fold higher mortality risk (adjusted hazard ratio [aHR]: 2.15 2.222.29 , P < .001) and 1.92-fold higher DCGF risk (aHR: 1.84 1.911.98 , P < .001) for kidney transplant recipients who developed an infection, although the magnitude of this higher risk varied across infection types (for example, 3.11-fold higher mortality risk for sepsis vs 1.62-fold for a UTI). Post-KT infections are common and substantially impact mortality and DCGF, even in the modern era. Kidney transplant recipients at high risk for infections might benefit from enhanced surveillance or follow-up to mitigate these risks.

MELD is MELD is MELD? Transplant center-level variation in waitlist mortality for candidates with the same biological MELD.

Recently, model for end-stage liver disease (MELD)-based liver allocation in the United States has been questioned based on concerns that waitlist mortality for a given biologic MELD (bMELD), calculated using laboratory values alone, might be higher at certain centers in certain locations across the country. Therefore, we aimed to quantify the center-level variation in bMELD-predicted mortality risk. Using Scientific Registry of Transplant Recipients (SRTR) data from January 2015 to December 2019, we modeled mortality risk in 33 260 adult, first-time waitlisted candidates from 120 centers using multilevel Poisson regression, adjusting for sex, and time-varying age and bMELD. We calculated a "MELD correction factor" using each center's random intercept and bMELD coefficient. A MELD correction factor of +1 means that center's candidates have a higher-than-average bMELD-predicted mortality risk equivalent to 1 bMELD point. We found that the "MELD correction factor" median (IQR) was 0.03 (-0.47, 0.52), indicating almost no center-level variation. The number of centers with "MELD correction factors" within ±0.5 points, and between ±0.5-± 1, ±1.0-±1.5, and ±1.5-±2.0 points was 62, 41, 13, and 4, respectively. No centers had waitlisted candidates with a higher-than-average bMELD-predicted mortality risk beyond ±2 bMELD points. Given that bMELD similarly predicts waitlist mortality at centers across the country, our results support continued MELD-based prioritization of waitlisted candidates irrespective of center.

Survival benefit of accepting kidneys from older donation after cardiac death donors.

Kidneys from older (age ≥50 years) donation after cardiac death (DCD50) donors are less likely to be transplanted due to inferior posttransplant outcomes. However, candidates who decline a DCD50 offer must wait for an uncertain future offer. To characterize the survival benefit of accepting DCD50 kidneys, we used 2010-2018 Scientific Registry for Transplant Recipients (SRTR) data to identify 92 081 adult kidney transplantation candidates who were offered a DCD50 kidney that was eventually accepted for transplantation. DCD50 kidneys offered to candidates increased from 590 in 2010 to 1441 in 2018. However, 34.6% of DCD50 kidneys were discarded. Candidates who accepted DCD50 offers had 49% decreased mortality risk (adjusted hazard ratio [aHR] 0.46 0.510.55 , cumulative mortality at 6-year 23.3% vs 34.0%, P < .001) compared with those who declined the same offer (decliners). Six years after their initial DCD50 offer decline, 43.0% of decliners received a deceased donor kidney transplant (DDKT), 6.3% received living donor kidney transplant (LDKT), 22.6% died, 22.0% were removed for other reasons, and 6.0% were still on the waitlist. Comparable survival benefit was observed even with DCD donors age ≥60 (aHR: 0.42 0.520.65 , P < .001). Accepting DCD50 kidneys was associated with a substantial survival benefit; providers and patients should consider these benefits when evaluating offers.

Liver transplantation in the United States during the COVID-19 pandemic: National and center-level responses.

COVID-19 has profoundly affected the American health care system; its effect on the liver transplant (LT) waitlist based on COVID-19 incidence has not been characterized. Using SRTR data, we compared observed LT waitlist registrations, waitlist mortality, deceased donor LTs (DDLT), and living donor LTs (LDLT) 3/15/2020-8/31/2020 to expected values based on historical trends 1/2016-1/2020, stratified by statewide COVID-19 incidence. Overall, from 3/15 to 4/30, new listings were 11% fewer than expected (IRR = 0.84 0.890.93 ), LDLTs were 49% fewer (IRR = 0.37 0.510.72 ), and DDLTs were 9% fewer (IRR = 0.85 0.910.97 ). In May, new listings were 21% fewer (IRR = 0.74 0.790.84 ), LDLTs were 42% fewer (IRR = 0.39 0.580.85 ) and DDLTs were 13% more (IRR = 1.07 1.151.23 ). Centers in states with the highest incidence 3/15-4/30 had 59% more waitlist deaths (IRR = 1.09 1.592.32 ) and 34% fewer DDLTs (IRR = 0.50 0.660.86 ). By August, waitlist outcomes were occurring at expected rates, except for DDLT (13% more across all incidences). While the early COVID-affected states endured major transplant practice changes, later in the pandemic the newly COVID-affected areas were not impacted to the same extent. These results speak to the adaptability of the transplant community in addressing the pandemic and applying new knowledge to patient care.

Inpatient COVID-19 outcomes in solid organ transplant recipients compared to non-solid organ transplant patients: A retrospective cohort.

Immunosuppression and comorbidities might place solid organ transplant (SOT) recipients at higher risk from COVID-19, as suggested by recent case series. We compared 45 SOT vs. 2427 non-SOT patients who were admitted with COVID-19 to our health-care system (March 1, 2020 - August 21, 2020), evaluating hospital length-of-stay and inpatient mortality using competing-risks regression. We compared trajectories of WHO COVID-19 severity scale using mixed-effects ordinal logistic regression, adjusting for severity score at admission. SOT and non-SOT patients had comparable age, sex, and race, but SOT recipients were more likely to have diabetes (60% vs. 34%, p < .001), hypertension (69% vs. 44%, p = .001), HIV (7% vs. 1.4%, p = .024), and peripheral vascular disorders (19% vs. 8%, p = .018). There were no statistically significant differences between SOT and non-SOT in maximum illness severity score (p = .13), length-of-stay (sHR: 0.9 1.11.4 , p = .5), or mortality (sHR: 0.1 0.41.6 , p = .19), although the severity score on admission was slightly lower for SOT (median [IQR] 3 [3, 4]) than for non-SOT (median [IQR] 4 [3-4]) (p = .042) Despite a higher risk profile, SOT recipients had a faster decline in disease severity over time (OR = 0.76 0.810.86 , p < .001) compared with non-SOT patients. These findings have implications for transplant decision-making during the COVID-19 pandemic, and insights about the impact of SARS-CoV-2 on immunosuppressed patients.

Quantifying infection risks in incompatible living donor kidney transplant recipients.

Desensitization has enabled incompatible living donor kidney transplantation (ILDKT) across HLA/ABO barriers, but added immunomodulation might put patients at increased risk of infections. We studied 475 recipients from our center from 2010 to 2015, categorized by desensitization intensity: none/compatible (n = 260), low (0-4 plasmaphereses, n = 47), moderate (5-9, n = 74), and high (≥10, n = 94). The 1-year cumulative incidence of infection was 50.1%, 49.8%, 66.0%, and 73.5% for recipients who received none, low, moderate, and high-intensity desensitization (P < .001). The most common infections were UTI (33.5% of ILDKT vs. 21.5% compatible), opportunistic (21.9% vs. 10.8%), and bloodstream (19.1% vs. 5.4%) (P < .001). In weighted models, a trend toward increased risk was seen in low (wIRR = 0.77 1.402.56 ,P = .3) and moderately (wIRR = 0.88 1.352.06 ,P = .2) desensitized recipients, with a statistically significant 2.22-fold (wIRR = 1.33 2.223.72 ,P = .002) increased risk in highly desensitized recipients. Recipients with ≥4 infections were at higher risk of prolonged hospitalization (wIRR = 2.62 3.574.88 , P < .001) and death-censored graft loss (wHR = 1.15 4.0113.95 ,P = .03). Post-KT infections are more common in desensitized ILDKT recipients. A subset of highly desensitized patients is at ultra-high risk for infections. Strategies should be designed to protect patients from the morbidity of recurrent infections, and to extend the survival benefit of ILDKT across the spectrum of recipients.

Delayed graft function and acute rejection following HLA-incompatible living donor kidney transplantation.

Incompatible living donor kidney transplant recipients (ILDKTr) have pre-existing donor-specific antibody (DSA) that, despite desensitization, may persist or reappear with resulting consequences, including delayed graft function (DGF) and acute rejection (AR). To quantify the risk of DGF and AR in ILDKT and downstream effects, we compared 1406 ILDKTr to 17 542 compatible LDKT recipients (CLDKTr) using a 25-center cohort with novel SRTR linkage. We characterized DSA strength as positive Luminex, negative flow crossmatch (PLNF); positive flow, negative cytotoxic crossmatch (PFNC); or positive cytotoxic crossmatch (PCC). DGF occurred in 3.1% of CLDKT, 3.5% of PLNF, 5.7% of PFNC, and 7.6% of PCC recipients, which translated to higher DGF for PCC recipients (aOR = 1.03 1.682.72 ). However, the impact of DGF on mortality and DCGF risk was no higher for ILDKT than CLDKT (p interaction > .1). AR developed in 8.4% of CLDKT, 18.2% of PLNF, 21.3% of PFNC, and 21.7% of PCC recipients, which translated to higher AR (aOR PLNF = 1.45 2.093.02 ; PFNC = 1.67 2.403.46 ; PCC = 1.48 2.243.37 ). Although the impact of AR on mortality was no higher for ILDKT than CLDKT (p interaction = .1), its impact on DCGF risk was less consequential for ILDKT (aHR = 1.34 1.621.95 ) than CLDKT (aHR = 1.96 2.292.67 ) (p interaction = .004). Providers should consider these risks during preoperative counseling, and strategies to mitigate them should be considered.