Serum ß2-Microglobulin Predicts Time to Recovery of Delayed Graft Function in Kidney Transplant Recipients.

BACKGROUND: Delayed graft function (DGF) after kidney transplantation is associated with adverse patients and allograft outcomes. A longer duration of DGF is predictive of worse graft outcomes compared to a shorter duration. Posttransplant serum ß2-microglobulin (B2M) is associated with long-term graft outcomes, but its relationship with DGF recovery is unknown. METHODS: We included all kidney-only transplant recipients with DGF enrolled in the E-DGF trial. Duration of DGF was defined as the interval between the transplant and the last dialysis session. We analyzed the association of standardized serum creatinine (Scr) and B2M on postoperative Days (POD) 1-7 during the subsequent days of DGF with the recovery of DGF. RESULTS: A total of 97 recipients with DGF were included. The mean duration of DGF was 11.0 ± 11.2 days. Higher Scr was not associated with the duration of DGF in unadjusted or adjusted models. Higher standardized B2M, in contrast, was associated with a prolonged duration of DGF. This association remained in models adjusting for baseline characteristics from POD 2 (3.19 days longer, 95% CI: 0.46-5.93; p = 0.02) through Day 6 of DGF (4.97 days longer, 95% CI: 0.75-9.20; p = 0.02). There was minimal change in mean Scr (0.01 ± 0. 10 mg/dL per day; p = 0.32), while B2M significantly decreased as the time to recovery approached (-0.14 ± 0.05 mg/L per day; p = 0.006), among recipients with DGF. CONCLUSION: B2M is more strongly associated with DGF recovery than Scr. Posttransplant B2M may be an important biomarker to monitor during DGF. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03864926.

Oxalate Nephropathy After Kidney Transplantation: Risk Factors and Outcomes of Two Phenotypes.

Describing risk factors and outcomes in kidney transplant recipients with oxalate nephropathy (ON) may help elucidate the pathogenesis and guide treatment strategies. We used a large single-center database to identify patients with ON and categorized them into delayed graft function with ON (DGF-ON) and late ON. Incidence density sampling was used to select controls. A total of 37 ON cases were diagnosed between 1/2011 and 1/2021. DGF-ON (n = 13) was diagnosed in 1.05% of the DGF population. Pancreatic atrophy on imaging (36.4% vs. 2.9%, p = 0.002) and gastric bypass history (7.7% vs. 0%; p = 0.06) were more common in DGF-ON than with controls with DGF requiring biopsy but without evidence of ON. DGF-ON was not associated with worse graft survival (p = 0.98) or death-censored graft survival (p = 0.48). Late ON (n = 24) was diagnosed after a mean of 78.2 months. Late ON patients were older (mean age 55.1 vs. 48.4 years; p = 0.02), more likely to be women (61.7% vs. 37.5%; p = 0.03), have gastric bypass history (8.3% vs. 0.8%; p = 0.02) and pancreatic atrophy on imaging (38.9% vs. 13.3%; p = 0.02). Late ON was associated with an increased risk of graft failure (HR 2.0; p = 0.07) and death-censored graft loss (HR 2.5; p = 0.10). We describe two phenotypes of ON after kidney transplantation: DGF-ON and late ON. Our study is the first to our knowledge to evaluate DGF-ON with DGF controls without ON. Although limited by small sample size, DGF-ON was not associated with adverse outcomes when compared with controls. Late ON predicted worse allograft outcomes.

Extreme Humid-Heat Exposure and Mortality Among Patients Receiving Dialysis.

RATIONALE & OBJECTIVE: Exposure to extreme heat events has been linked to increased morbidity and mortality in the general population. Patients receiving maintenance dialysis may be vulnerable to greater risks from these events, but this is not well understood. We characterized the association of extreme heat events and the risk of death among patients receiving dialysis in the United States. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Data from the US Renal Data System were used to identify adults living in US urban settlements prone to extreme heat who initiated maintenance dialysis between 1997 and 2016. EXPOSURE: An extreme heat event, defined as a time-updated heat index (a humid-heat metric) exceeding 40.6°C for≥2 days or 46.1°C for≥1day. OUTCOME: Death. ANALYTICAL APPROACH: Cox proportional hazards regression to estimate the elevation in risk of death during a humid-heat event adjusted for age, sex, year of dialysis initiation, dialysis modality, poverty level, and climate region. Interactions between humid-heat and these same factors were explored. RESULTS: Among 945,251 adults in 245 urban settlements, the mean age was 63 years, and 44% were female. During a median follow-up period of 3.6 years, 498,049 adults were exposed to at least 1 of 7,154 extreme humid-heat events, and 500,025 deaths occurred. In adjusted models, there was an increased risk of death (hazard ratio 1.18 [95% CI, 1.15-1.20]) during extreme humid-heat exposure. The relative mortality risk was higher among patients living in the Southeast (P<0.001) compared with the Southwest. LIMITATIONS: Possibility of exposure misclassification, did not account for land use and air pollution co-exposures. CONCLUSIONS: This study suggests that patients receiving dialysis face an increased risk of death during extreme humid-heat exposure. PLAIN-LANGUAGE SUMMARY: Patients who receive dialysis are vulnerable to extreme weather events, and rising global temperatures may bring more frequent extreme heat events. We sought to determine whether extreme heat exposure was associated with an increased risk of death in urban-dwelling patients receiving dialysis across the United States. We found that people receiving dialysis were more likely to die during extreme humid-heat events, defined by a heat index exceeding 40.6°C (105°F) for≥2 days or 46.1°C (115°F) for≥1day. These findings inform the nephrology community about the potential importance of protecting patients receiving maintenance dialysis from the risks associated with extreme heat.

Multiplicative Impact of Adverse Social Determinants of Health on Outcomes in Lupus Nephritis: A Meta-analysis and Systematic Review.

OBJECTIVE: Social determinants of health (SDoH) likely contribute to outcome disparities in lupus nephritis (LN). Understanding the overall burden and contribution of each domain could guide future health equity-focused interventions to improve outcomes and reduce disparities in LN. Objectives of this meta-analysis were to 1) determine the association of overall SDoH and specific SDoH domains on LN outcomes and 2) develop a framework for the multidimensional impact of SDoH on LN outcomes. METHODS: We performed a comprehensive search of studies measuring associations between SDoH and LN outcomes. We examined pooled odds of poor LN outcomes including death, end-stage kidney disease, or cardiovascular disease in patients with and without adverse SDoH. Additionally, we calculated the pooled odds ratios of outcomes by four SDoH domains: individual (eg, insurance), health care (eg, fragmented care), community (eg, neighborhood socioeconomic status), and health behaviors (eg, smoking). RESULTS: Among 531 screened studies, 31 meeting inclusion criteria and 13 with raw data were included in meta-analysis. Pooled odds of poor outcomes were 1.47-fold higher in patients with any adverse SDoH. Patients with adverse SDoH in individual and health care domains had 1.64-fold and 1.77-fold higher odds of poor outcomes. We found a multiplicative impact of having two or more adverse SDoH on LN outcomes. Black patients with public insurance and fragmented care had 12-fold higher odds of poor LN outcomes. CONCLUSION: Adverse SDoH is associated with poor LN outcomes. Having two or more adverse SDoH, specifically in different SDoH domains, had a multiplicative impact leading to worse LN outcomes, widening disparities.

Effect of End-Stage Renal Disease Prospective Payment System on Utilization of Peritoneal Dialysis in Patients with Kidney Allograft Failure.

INTRODUCTION: The Center for Medicare and Medicaid Services introduced an End-Stage Renal Disease Prospective Payment System (PPS) in 2011 to increase the utilization of home dialysis modalities, including peritoneal dialysis (PD). Several studies have shown a significant increase in PD utilization after PPS implementation. However, its impact on patients with kidney allograft failure remains unknown. METHODS: We conducted an interrupted time series analysis using data from the US Renal Data System (USRDS) that include all adult kidney transplant recipients with allograft failure who started dialysis between 2005 and 2019. We compared the PD utilization in the pre-PPS period (2005-2010) to the fully implemented post-PPS period (2014-2019) for early (within 90 days) and late (91-365 days) PD experience. RESULTS: A total of 27,507 adult recipients with allograft failure started dialysis during the study period. There was no difference in early PD utilization between the pre-PPS and the post-PPS period in either immediate change (0.3% increase; 95% CI: -1.95%, 2.54%; p = 0.79) or rate of change over time (0.28% increase per year; 95% CI: -0.16%, 0.72%; p = 0.18). Subgroup analyses revealed a trend toward higher PD utilization post-PPS in for-profit and large-volume dialysis units. There was a significant increase in PD utilization in the post-PPS period in units with low PD experience in the pre-PPS period. Similar findings were seen for the late PD experience. CONCLUSION: PPS did not significantly increase the overall utilization of PD in patients initiating dialysis after allograft failure.

Receipt of rheumatology care and lupus-specific labs among young adults with systemic lupus erythematosus: A US Medicare retention in care cohort study.

OBJECTIVE: In systemic lupus erythematosus, poor disease outcomes occur in young adults, patients identifying as Black or Hispanic, and socioeconomically disadvantaged patients. These identities and social factors differentially shape care access and quality that contribute to lupus health disparities in the US. Thus, our objective was to measure markers of care access and quality, including rheumatology visits (longitudinal care retention) and lupus-specific serology testing, by race and ethnicity, neighborhood disadvantage, and geographic context. METHODS: This cohort study used a geo-linked 20% national sample of young adult Medicare beneficiaries (ages 18-35) with lupus-coded encounters and a 1-year assessment period. Retention in lupus care required a rheumatology visit in each 6-month period, and serology testing required ≥1 complement or dsDNA antibody test within the year. Multivariable logistic regression models were fit for visit-based retention and serology testing to determine associations with race and ethnicity, neighborhood disadvantage, and geography. RESULTS: Among 1,036 young adults with lupus, 39% saw a rheumatologist every 6 months and 28% had serology testing. White beneficiaries from the least disadvantaged quintile of neighborhoods had higher visit-based retention than other beneficiaries (64% vs 30%-60%). Serology testing decreased with increasing neighborhood disadvantage quintile (aOR 0.80; 95% CI 0.71, 0.90) and in the Midwest (aOR 0.46; 0.30, 0.71). CONCLUSION: Disparities in care, measured by rheumatology visits and serology testing, exist by neighborhood disadvantage, race and ethnicity, and region among young adults with lupus, despite uniform Medicare coverage. Findings support evaluating lupus care quality measures and their impact on US lupus outcomes.

Incidence, Risk Factors, and Outcomes of Posttransplant Erythrocytosis Among Simultaneous Pancreas-Kidney Transplant Recipients.

Background: Posttransplant erythrocytosis (PTE) is a well-known complication of kidney transplantation. However, the risk and outcomes of PTE among simultaneous pancreas-kidney transplant (SPKT) recipients are poorly described. Methods: We analyzed all SPKT recipients at our center between 1998 and 2021. PTE was defined as at least 2 consecutive hematocrit levels of >51% within the first 2 y of transplant. Controls were selected at a ratio of 3:1 at the time of PTE occurrence using event density sampling. Risk factors for PTE and post-PTE graft survival were identified. Results: Of 887 SPKT recipients, 108 (12%) developed PTE at a median of 273 d (interquartile range, 160-393) after transplantation. The incidence rate of PTE was 7.5 per 100 person-years. Multivariate analysis found pretransplant dialysis (hazard ratio [HR]: 3.15; 95% confidence interval [CI], 1.67-5.92; P < 0.001), non-White donor (HR: 2.14; 95% CI, 1.25-3.66; P = 0.01), female donor (HR: 1.50; 95% CI, 1.0-2.26; P = 0.05), and male recipient (HR: 2.33; 95% CI, 1.43-3.70; P = 0.001) to be associated with increased risk. The 108 cases of PTE were compared with 324 controls. PTE was not associated with subsequent pancreas graft failure (HR: 1.36; 95% CI, 0.51-3.68; P = 0.53) or kidney graft failure (HR: 1.16; 95% CI, 0.40-3.42; P = 0.78). Conclusions: PTE is a common complication among SPKT recipients, even in the modern era of immunosuppression. PTE among SPKT recipients was not associated with adverse graft outcomes, likely due to appropriate management.

Association of Circulating 25-Hydroxyvitamin D and Recurrence of Glomerulonephritis in Kidney Transplant Recipients: The Wisconsin Allograft Recipient Database (WisARD).

Background: Recurrence of glomerulonephritis (GN) is a significant contributor to long-term allograft failure among kidney transplant recipients (KTRs) with kidney failure because of GN. Accumulating evidence has revealed the role of vitamin D in both innate and adaptive immunity. Although vitamin D deficiency is common among KTRs, the association between 25-hydroxyvitamin D (25[OH]D) and GN recurrence in KTRs remains unclear. Methods: We analyzed data from KTRs with kidney failure caused by GN who received a transplant at our center from 2000 to 2019 and had at least 1 valid posttransplant serum 25(OH)D measurement. Survival analyses were performed using a competing risk regression model considering other causes of allograft failure, including death, as competing risk events. Results: A total of 67 cases of GN recurrence were identified in 947 recipients with GN followed for a median of 7.0 y after transplant. Each 1 ng/mL lower serum 25(OH)D was associated with a 4% higher hazard of recurrence (subdistribution hazard ratio [HR]: 1.04; 95% confidence interval [CI], 1.01-1.06). Vitamin D deficiency (≤20 ng/mL) was associated with a 2.99-fold (subdistribution HR: 2.99; 95% CI, 1.56-5.73) higher hazard of recurrence compared with vitamin D sufficiency (≥30 ng/mL). Results were similar after further adjusting for concurrent urine protein-creatinine ratio, serum albumin, and estimated glomerular filtration rate (eGFR). Conclusions: Posttransplant vitamin D deficiency is associated with a higher hazard of GN recurrence in KTRs. Further prospective observational studies and clinical trials are needed to determine any causal role of vitamin D in the recurrence of GN after kidney transplantation. More in vitro and in vivo experiments would be helpful to understand its effects on autoimmune and inflammation processes.

Twelve Thousand Kidney Transplants Over More Than 55 Y: A Single-center Experience.

Background: Kidney transplant outcomes have dramatically improved since the first successful transplant in 1954. In its early years, kidney transplantation was viewed more skeptically. Today it is considered the treatment of choice among patients with end-stage kidney disease. Methods: Our program performed its first kidney transplant in 1966 and recently performed our 12 000th kidney transplant. Here, we review and describe our experience with these 12 000 transplants. Transplant recipients were analyzed by decade of date of transplant: 1966-1975, 1976-1985, 1986-1995, 1996-2005, 2006-2015, and 2016-2022. Death-censored graft failure and mortality were outcomes of interest. Results: Of 12 000 kidneys, 247 were transplanted from 1966 to 1975, 1147 from 1976 to 1985, 2194 from 1986 to 1995, 3147 from 1996 to 2005, 3046 from 2006 to 2015, and 2219 from 2016 to 2022 compared with 1966-1975, there were statistically significant and progressively lower risks of death-censored graft failure at 1 y, 5 y, and at last follow-up in all subsequent eras. Although mortality at 1 y was lower in all subsequent eras after 1986-1995, there was no difference in mortality at 5 y or the last follow-up between eras. Conclusions: In this large cohort of 12 000 kidneys from a single center, we observed significant improvement in outcomes over time. Kidney transplantation remains a robust and ever-growing and improving field.