Faculty Bibliography

INTRODUCTION:Incidental kidneys cysts are typically considered benign, but the presence of cysts is more frequent in individuals with other early markers of kidney disease. We studied the association of donor kidney cysts with donor and recipient outcomes after living donor kidney transplantation. METHODS:We retrospective identified 860 living donor transplants at our center (1/1/2011-7/31/2022) without missing data. Donor cysts were identified by review of pre-donation CT scan reports. We used linear regression to study the association between donor cysts and 6-month single-kidney estimated glomerular filtration rate (eGFR) increase, and time-to-event analyses to study the association between donor cysts and recipient death-censored graft failure. RESULTS:Among donors, 77% donors had no kidney cysts, 13% had ≥1 cyst on the kidney not donated, and 11% only had cysts on the donated kidney. In adjusted linear regression, cysts on the donated kidney and kidney not donated were not significantly associated with 6-month single-kidney eGFR increase. Among transplants, 17% used a transplanted kidney with a cyst and 6% were from donors with cysts only on the kidney not transplanted. There was no association between donor cyst group and post-transplant death-censored graft survival. Results were similar in sensitivity analyses comparing transplants using kidneys with no cysts versus 1-2 cysts versus ≥3 cysts. CONCLUSIONS:Kidney cysts in living kidney donors were not associated with donor kidney recovery or recipient allograft longevity, suggesting incidental kidney cysts need not be taken into account when determining living donor candidate suitability or the laterality of planned donor nephrectomy.

Although a few registry-based studies have shown associations between receiving kidney allografts from Black donors and shorter allograft survival, detailed, large, single-center studies accounting for common confounding factors are lacking. Furthermore, pathologic alterations underlying this potential disparity have not been systematically studied. We performed a retrospective clinical-pathological study of kidney transplant recipients who received kidney allografts from either Black (n = 407) or White (n = 1,494) donors at Columbia University Irving Medical Center from 2005 to 2018, with median follow-up of 4.5 years post-transplantation. Black donor race was independently associated with allograft failure (adjusted HR = 1.34, p = 0.02) and recipients of kidney allografts from Black donors had a higher incidence of collapsing glomerulopathy [7.4% vs. 1.9%, OR = 4.17, p < 0.001]. When causes of allograft failure were examined, only allograft failure following development of collapsing glomerulopathy was more frequent in recipients of allografts from Black donors [15% vs. 5%, OR = 3.16, p = 0.004]. Notably, when patients who developed collapsing glomerulopathy were excluded from analysis, receiving kidney allografts from Black donors was not independently associated with allograft failure (adjusted HR = 1.24, p = 0.10). These findings revealed that, compared with recipients of kidney allografts from White donors, recipients of kidneys from Black donors have modestly shorter allograft survival and a higher probability of developing collapsing glomerulopathy, which negatively impacts allograft outcome. Identification of collapsing glomerulopathy risk factors may help decrease this complication and improve allograft survival, which optimally may reduce racial disparities post-transplantation.

OBJECTIVES:Chart review as the current gold standard for phenotype evaluation cannot support observational research on electronic health records and claims data sources at scale. We aimed to evaluate the ability of structured data to support efficient and interpretable phenotype evaluation as an alternative to chart review. MATERIALS AND METHODS:We developed Knowledge-Enhanced Electronic Profile Review (KEEPER) as a phenotype evaluation tool that extracts patient's structured data elements relevant to a phenotype and presents them in a standardized fashion following clinical reasoning principles. We evaluated its performance (interrater agreement, intermethod agreement, accuracy, and review time) compared to manual chart review for 4 conditions using randomized 2-period, 2-sequence crossover design. RESULTS:Case ascertainment with KEEPER was twice as fast compared to manual chart review. 88.1% of the patients were classified concordantly using charts and KEEPER, but agreement varied depending on the condition. Missing data and differences in interpretation accounted for most of the discrepancies. Pairs of clinicians agreed in case ascertainment in 91.2% of the cases when using KEEPER compared to 76.3% when using charts. Patient classification aligned with the gold standard in 88.1% and 86.9% of the cases respectively. CONCLUSION:Structured data can be used for efficient and interpretable phenotype evaluation if they are limited to relevant subset and organized according to the clinical reasoning principles. A system that implements these principles can achieve noninferior performance compared to chart review at a fraction of time.

BACKGROUND:The Organ Procurement Transplant Network (OPTN)/United Network for Organ Sharing (UNOS) registry is an important national registry in the field of solid organ transplantation. Data collected are mission critical, given its role in organ allocation prioritization, program performance monitoring by both the OPTN and the Centers for Medicare & Medicaid Services, and countless observational analyses that helped to move the field forward. Despite the multifaceted importance of the OPTN/UNOS database, there are clear indications that investments in the database to ensure the quality and reliability of the data have been lacking. METHODS:This analysis outlines 2 examples: (1) primary diagnosis for patients who are receiving a second transplant and (2) reporting peripheral vascular disease in kidney transplantation to illustrate the extensive challenges facing the veracity and integrity of the OPTN/UNOS database today. RESULTS:Despite guidance that repeat kidney transplant patients should be coded as "retransplant/graft failure" rather than their native kidney disease, only 59% of new incident patients are coded in this manner. Peripheral vascular disease prevalence more than doubled in a 20-y span when the variable became associated with risk adjustment. CONCLUSIONS:This article summarizes critical gaps in the OPTN/UNOS database, and we bring forward ideas and proposals for consideration as a path toward improvement.

IMPORTANCE:Disparities in kidney transplant referral and waitlisting contribute to disparities in kidney disease outcomes. Whether these differences are rooted in population differences in comorbidity burden is unclear. OBJECTIVE:To examine whether disparities in kidney transplant waitlisting were present among a young, relatively healthy cohort of patients unlikely to have medical contraindications to kidney transplant. DESIGN, SETTING, AND PARTICIPANTS:This retrospective cohort study used the US Renal Data System Registry to identify patients with end-stage kidney disease who initiated dialysis between January 1, 2005, and December 31, 2019. Patients who were older than 40 years, received a preemptive transplant, were preemptively waitlisted, or had documented medical comorbidities other than hypertension or smoking were excluded, yielding an analytic cohort of 52 902 patients. Data were analyzed between March 1, 2022, and February 1, 2023. MAIN OUTCOME(S) AND MEASURE(S):Kidney transplant waitlisting after dialysis initiation. RESULTS:Of 52 902 patients (mean [SD] age, 31 [5] years; 31 132 [59%] male; 3547 [7%] Asian/Pacific Islander, 20 782 [39%] Black/African American, and 28 006 [53%] White) included in the analysis, 15 840 (30%) were waitlisted for a kidney transplant within 1 year of dialysis initiation, 11 122 (21%) were waitlisted between 1 and 5 years after dialysis initiation, and 25 940 (49%) were not waitlisted by 5 years. Patients waitlisted within 1 year of dialysis initiation were more likely to be male, to be White, to be employed full time, and to have had predialysis nephrology care. There were large state-level differences in the proportion of patients waitlisted within 1 year (median, 33%; range, 15%-58%). In competing risk regression, female sex (adjusted subhazard ratio [SHR], 0.92; 95% CI, 0.90-0.94), Hispanic ethnicity (SHR, 0.77; 95% CI, 0.75-0.80), and Black race (SHR, 0.66; 95% CI, 0.64-0.68) were all associated with lower waitlisting after dialysis initiation. Unemployment (SHR, 0.47; 95% CI, 0.45-0.48) and part-time employment (SHR, 0.74; 95% CI, 0.70-0.77) were associated with lower waitlisting compared with full-time employment, and more than 1 year of predialysis nephrology care, compared with none, was associated with greater waitlisting (SHR, 1.51; 95% CI, 1.46-1.56). CONCLUSIONS AND RELEVANCE:This retrospective cohort study found that fewer than one-third of patients without major medical comorbidities were waitlisted for a kidney transplant within 1 year of dialysis initiation, with sociodemographic disparities in waitlisting even in this cohort of young, relatively healthy patients unlikely to have a medical contraindication to transplantation. Transplant policy changes are needed to increase transparency and address structural barriers to waitlist access.

SIGNIFICANCE STATEMENT:Effects of reduced access to external data by transplant registries to improve accuracy and completeness of the collected data are compounded by different data management processes at three US organizations that maintain kidney transplant-related datasets. This analysis suggests that the datasets have large differences in reported outcomes that vary across different subsets of patients. These differences, along with recent disclosure of previously missing outcomes data, raise important questions about completeness of the outcome measures. Differences in recorded deaths seem to be increasing in recent years, reflecting the adverse effects of restricted access to external data sources. Although these registries are invaluable sources for the transplant community, discrepancies and incomplete reporting risk undermining their value for future analyses, particularly when used for developing national transplant policy or regulatory measures. BACKGROUND:Central to a transplant registry's quality are accuracy and completeness of the clinical information being captured, especially for important outcomes, such as graft failure or death. Effects of more limited access to external sources of death data for transplant registries are compounded by different data management processes at the United Network for Organ Sharing (UNOS), the Scientific Registry of Transplant Recipients (SRTR), and the United States Renal Data System (USRDS). METHODS:This cross-sectional registry study examined differences in reported deaths among kidney transplant candidates and recipients of kidneys from deceased and living donors in 2000 through 2019 in three transplant datasets on the basis of data current as of 2020. We assessed annual death rates and survival estimates to visualize trends in reported deaths between sources. RESULTS:The UNOS dataset included 77,605 deaths among 315,346 recipients and 61,249 deaths among 275,000 nonpreemptively waitlisted candidates who were never transplanted. The SRTR dataset included 87,149 deaths among 315,152 recipients and 60,042 deaths among 259,584 waitlisted candidates. The USRDS dataset included 89,515 deaths among 311,955 candidates and 63,577 deaths among 238,167 waitlisted candidates. Annual death rates among the prevalent transplant population show accumulating differences across datasets-2.31%, 4.00%, and 4.03% by 2019 from UNOS, SRTR, and USRDS, respectively. Long-term survival outcomes were similar among nonpreemptively waitlisted candidates but showed more than 10% discordance between USRDS and UNOS among transplanted patients. CONCLUSIONS:Large differences in reported patient outcomes across datasets seem to be increasing, raising questions about their completeness. Understanding the differences between these datasets is essential for accurate, reliable interpretation of analyses that use these data for policy development, regulatory oversight, and research. PODCAST:This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/JASN/2023_10_24_JASN0000000000000194.mp3.

RATIONALE & OBJECTIVE/OBJECTIVE:The clinical implications of the discrepancy between cystatin C (cysC)- and serum creatinine (Scr)-estimated glomerular filtration rate (eGFR) in patients with heart failure (HF) and reduced ejection fraction (HFrEF) are unknown. STUDY DESIGN/METHODS:Post-hoc analysis of randomized trial data. SETTING & PARTICIPANTS/METHODS:1,970 patients with HFrEF enrolled in PARADIGM-HF with available baseline cysC and Scr measurements. EXPOSURE/METHODS:). OUTCOMES/RESULTS:Clinical outcomes included the PARADIGM-HF primary end point (composite of cardiovascular [CV] mortality or HF hospitalization), CV mortality, all-cause mortality, and worsening kidney function. We also examined poor health-related quality of life (HRQoL), frailty, and worsening HF (WHF), defined as HF hospitalization, emergency department visit, or outpatient intensification of therapy between baseline and 8-month follow-up. ANALYTICAL APPROACH/METHODS:at 8-month follow-up. RESULTS:(P<0.001). LIMITATIONS/CONCLUSIONS:Lack of gold-standard assessment of kidney function. CONCLUSIONS:. PLAIN-LANGUAGE SUMMARY/UNASSIGNED:) were associated with worse clinical outcomes (including mortality), poor quality of life, and frailty. In patients with progressive heart failure, which is characterized by muscle loss and poor nutritional status, the decline in kidney function was more pronounced when eGFR was estimated using cysC rather than Scr.

The proportion of kidneys procured for transplantation but not utilized exceeds 20% in the United States. Factors associated with nonutilization are complex, and further understanding of novel causes are critically important. We used the national Scientific Registry of Transplant Recipients data (2010-2022) to evaluate associations of Distressed Community Index (DCI) of deceased donor residence and likelihood of kidney nonutilization (n = 209 413). Deceased donors from higher distressed communities were younger, had an increased history of hypertension and diabetes, were CDC high-risk, and had higher terminal creatinine and donation after brain death. Mechanisms and circumstances of death varied significantly by DCI. The proportion of kidney nonutilization was 19.9%, which increased by DCI quintile (Q1 = 18.1% to Q5 = 21.6%). The adjusted odds ratio of nonutilization from the highest quintile DCI communities was 1.22 (95% CI = 1.16-1.28; reference = lowest DCI), which persisted stratified by donor race. Donors from highly distressed communities were highly variable by the donor service area (range: 1%-51%; median = 21%). There was no increased risk for delayed graft function or death-censored graft loss by donor DCI but modest increased adjusted hazard for overall graft loss (high DCI = 1.05; 95% CI = 1.01-1.10; reference = lowest DCI). Results indicate that donor residential distress is associated with significantly higher rates of donor kidney nonutilization with notable regional variation and minimal impact on recipient outcomes.