Faculty Bibliography

BACKGROUND:Although electrolyte abnormalities are common among patients with COVID-19, very little has been reported on magnesium homeostasis in these patients. Here we report the incidence of hypermagnesemia, and its association with outcomes among patients admitted with COVID-19. METHODS:We retrospectively identified all patients with a positive test result for SARS-CoV-2 who were admitted to a large quaternary care center in New York City in spring 2020. Details of the patients' demographics and hospital course were obtained retrospectively from medical records. Patients were defined as having hypermagnesemia if their median magnesium over the course of their hospitalization was >2.4 mg/dl. RESULTS:<0.001). CONCLUSIONS:In conclusion, we identified an association between hypermagnesemia among patients hospitalized with COVID-19 and increased mortality. Although the exact mechanism of this relationship remains unclear, hypermagnesemia potentially represents increased cell turnover and higher severity of illness, which is frequently associated with more severe forms of AKI.

The COVID-19 pandemic has affected all portions of the global population. However, many factors have been shown to be particularly associated with COVID-19 mortality including demographic characteristics, behavior, comorbidities, and social conditions. Kidney transplant candidates may be particularly vulnerable to COVID-19 as many are dialysis-dependent and have comorbid conditions. We examined factors associated with COVID-19 mortality among kidney transplant candidates from the National Scientific Registry of Transplant Recipients from March 1 to December 1, 2020. We evaluated crude rates and multivariable incident rate ratios (IRR) of COVID-19 mortality. There were 131 659 candidates during the study period with 3534 all-cause deaths and 384 denoted a COVID-19 cause (5.00/1000 person years). Factors associated with increased COVID-19 mortality included increased age, males, higher body mass index, and diabetes. In addition, Blacks (IRR = 1.96, 95% C.I.: 1.43-2.69) and Hispanics (IRR = 3.38, 95% C.I.: 2.46-4.66) had higher COVID-19 mortality relative to Whites. Patients with lower educational attainment, high school or less (IRR = 1.93, 95% C.I.: 1.19-3.12, relative to post-graduate), Medicaid insurance (IRR = 1.73, 95% C.I.: 1.26-2.39, relative to private), residence in most distressed neighborhoods (fifth quintile IRR = 1.93, 95% C.I.: 1.28-2.90, relative to first quintile), and most urban and most rural had higher adjusted rates of COVID-19 mortality. Among kidney transplant candidates in the United States, social determinants of health in addition to demographic and clinical factors are significantly associated with COVID-19 mortality.

Unfavourable procurement biopsy findings are the most common reason for deceased donor kidney discard in the United States. We sought to assess the association between biopsy findings and post-transplant outcomes when donor characteristics are accounted for. We used registry data to identify 1566 deceased donors of 3132 transplanted kidneys (2015-2020) with discordant right/left procurement biopsy classification and performed time-to-event analyses to determine the association between optimal histology and hazard of death-censored graft failure or death. We then repeated all analyses using a local cohort of 147 donors of kidney pairs with detailed procurement histology data available (2006-2016). Among transplanted kidney pairs in the national cohort, there were no significant differences in incidence of delayed graft function or primary nonfunction. Time to death-censored graft failure was not significantly different between recipients of optimal versus suboptimal kidneys. Results were similar in analyses using the local cohort. Regarding recipient survival, analysis of the national, but not local, cohort showed optimal kidneys were associated with a lower hazard of death (adjusted HR 0.68, 95% CI 0.52-0.90, P = 0.006). In conclusion, in a large national cohort of deceased donor kidney pairs with discordant right/left procurement biopsy findings, we found no association between histology and death-censored graft survival.

BACKGROUND:Kidney transplantation is associated with the best outcomes for most patients with ESKD. The national Kidney Allocation System prioritizes patients with Estimated Post-Transplant Survival (EPTS) scores in the top 20% for expedited access to optimal deceased donor kidneys. METHODS:We studied adults aged ≥18 years in the United States Renal Data System with top 20% EPTS scores who had been preemptively waitlisted or initiated dialysis in 2015-2017. We evaluated time to waitlist placement, transplantation, and mortality with unadjusted and multivariable survival models. RESULTS:Of 42,445 patients with top 20% EPTS scores (mean age, 38.0 years; 57% male; 59% White patients, and 31% Black patients), 7922 were preemptively waitlisted. Among 34,523 patients initiating dialysis, the 3-year cumulative waitlist placement incidence was 37%. Numerous factors independently associated with waitlisting included race, income, and having noncommercial insurance. For example, waitlisting was less likely for Black versus White patients, and for patients in the lowest-income neighborhoods versus those in the highest-income neighborhoods. Among patients initiating dialysis, 61% lost their top 20% EPTS status within 30 months versus 18% of patients who were preemptively listed. The 3-year incidence of deceased and living donor transplantation was 5% and 6%, respectively, for patients who initiated dialysis and 26% and 44%, respectively, for patients who were preemptively listed. CONCLUSIONS:Many patients with ESKDqualifying with top 20% EPTS status are not placed on the transplant waiting list in a timely manner, with significant variation on the basis of demographic and social factors. Patients who are preemptively listed are more likely to receive benefits of top 20% EPTS status. Efforts to expedite care for qualifying candidates are needed, and automated transplant referral for patients with the best prognoses should be considered. PODCAST/UNASSIGNED:This article contains a podcast athttps://www.asn-online.org/media/podcast/JASN/2021_07_30_JASN2020081146.mp3.

The deceased donor kidney allocation system in the United States has undergone several rounds of iterative changes, but these changes were not explicitly designed to address the geographic variation in access to transplantation. The new allocation system, expected to start in December 2020, changes the definition of "local allocation" from the Donation Service Area to 250 nautical mile circles originating from the donor hospital. While other solid organs have adopted a similar approach, the larger number of both kidney transplant centers and transplant candidates is likely to have different consequences. Here, we discuss the incredible increase in complexity in allocation, discuss some of the likely intended and unintended consequences, and propose metrics to monitor the new system.

Cognitive biases shown to impact medical decision-making include left-digit bias, the tendency to focus on a continuous variable's leftmost digit. We hypothesized that left-digit bias impacts deceased donor kidney utilization through heuristic processing of donor age and creatinine. We used US registry data to identify 87 019 kidneys recovered (2015-2019) and compared the proportion around thresholds for donor age (69 vs. 70 years) and creatinine (1.9 vs. 2.0 mg/dl), then compared the risk of kidney discard. Kidneys from donors aged 70 vs. 69 years were more frequently discarded (77% vs. 65%, p < .001), with higher risk of discard even after adjusting for KDRI (adjusted RR 1.11, 95% CI 1.02-1.21, p = .018). Similarly, kidneys from donors with final creatinine 2.0 vs. 1.9 mg/dl were more frequently discarded (37% vs. 29%, p < .001), with higher risk of discard after adjusting for KDRI (adjusted RR 1.19, 95% CI 1.07-1.33, p = .001). However, no significant left-digit effect was found when examining other donor age (39/40, 49/50, 59/60 years) or creatinine (0.9/1.0, 2.9/3.0 mg/dl) thresholds. The findings suggest a possible left-digit effect affecting kidney utilization at specific thresholds. Additional investigations of the impact of this and other heuristics on organ utilization are needed to identify potential areas for decision-making interventions aimed at reducing kidney discard.