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Augustine JJ, Liaqat A, Arrigain S, Schold JD, Poggio ED. Performance of estimated glomerular filtration rate equations in Black living kidney donor candidates. Clin Transplant 2024; 38:e15198. [PMID: 37964662 DOI: 10.1111/ctr.15198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 10/18/2023] [Accepted: 11/08/2023] [Indexed: 11/16/2023]
Abstract
INTRODUCTION New estimated glomerular filtration rate (eGFR) equations using serum creatinine and/or cystatin C have been derived to eliminate adjustment by perceived Black ancestry. We sought to analyze the performance of newer eGFR equations among Black living kidney donor candidates. METHODS Black candidates (n = 64) who had measured iothalamate GFR between January 2015 and October 2021 were included, and eGFR was calculated using race adjusted (eGFRcr2009 and eGFRcr-cys2012) and race unadjusted (eGFRcys2012, eGFRcr2021, and eGFRcr-cys2021) CKD-EPI equations. Bias and accuracy were calculated. RESULTS The eGFRcr2021 equation had a negative bias of 9 mL/min/1.73 m2 , while other equations showed a modest positive bias. Accuracy within 10% and 30% was greatest using the eGFRcr-cys2021 equation. With the eGFRcr2021 equation, 9.4% of donors with an mGFR > 80 mL/min/1.73 m2 were misclassified as having an eGFR < 80 mL/min/1.73 m2 . eGFR was also compared among 18 kidney donors at 6-24 months post-donation. Post-donation, the percentage of donors with an eGFR < 60 mL/min/1.73 m2 was 44% using the eGFRcr2021 equation compared to 11% using the eGFRcr-cys2021 equation. CONCLUSION The CKD-EPICr2021 equation appears to underestimate true GFR in Black living donor candidates. Alternatively, compared to CKD-EPICr2021, the CKD-EPICr-CysC2021 equation appears to perform with less bias and improved accuracy.
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Affiliation(s)
- Joshua J Augustine
- Department of Nephrology, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Aimen Liaqat
- Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Susana Arrigain
- Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Jesse D Schold
- Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Department of Epidemiology, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Emilio D Poggio
- Department of Nephrology, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio, USA
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Williams P. Retaining Race in Chronic Kidney Disease Diagnosis and Treatment. Cureus 2023; 15:e45054. [PMID: 37701164 PMCID: PMC10495104 DOI: 10.7759/cureus.45054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2023] [Indexed: 09/14/2023] Open
Abstract
The best overall measure of kidney function is glomerular filtration rate (GFR) as commonly estimated from serum creatinine concentrations (eGFRcr) using formulas that correct for the higher average creatinine concentrations in Blacks. After two decades of use, these formulas have come under scrutiny for estimating GFR differently in Blacks and non-Blacks. Discussions of whether to include race (Black vs. non-Black) in the calculation of eGFRcr fail to acknowledge that the original race-based eGFRcr provided the same CKD treatment recommendations for Blacks and non-Blacks based on directly (exogenously) measured GFR. Nevertheless, the National Kidney Foundation and the American Society of Nephrology Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease removed race in CKD treatment guidelines and pushed for the immediate adoption of a race-free eGFRcr formula by physicians and clinical laboratories. This formula is projected to negate CKD in 5.51 million White and other non-Black adults and reclassify CKD to less severe stages in another 4.59 million non-Blacks, in order to expand treatment eligibility to 434,000 Blacks not previously diagnosed and to 584,000 Blacks previously diagnosed with less severe CKD. This review examines: 1) the validity of the arguments for removing the original race correction, and 2) the performance of the proposed replacement formula. Excluding race in the derivation of eGFRcr changed the statistical bias from +3.7 to -3.6 ml/min/1.73m2 in Blacks and from +0.5 to +3.9 in non-Blacks, i.e., promoting CKD diagnosis in Blacks at the cost of restricting diagnosis in non-Blacks. By doing so, the revised eGFRcr greatly exaggerates the purported racial disparity in CKD burden. Claims that the revised formulas identify heretofore undiagnosed CKD in Blacks are not supported when studies that used kidney failure replacement therapy and mortality are interpreted as proxies for baseline CKD. Alternatively, a race-stratified eGFRcr (i.e., separate equations for Blacks and non-Blacks) would provide the least biased eGFRcr for both Blacks and non-Blacks and the best medical treatment for all patients.
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Affiliation(s)
- Paul Williams
- Life Sciences, Lawrence Berkeley National Laboratory, Berkeley, USA
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Al Jurdi A, Safa K. Impact of the New Glomerular Filtration Rate Formulas on Kidney Function Assessment in Living Kidney Donors and Candidates. Transplant Direct 2023; 9:e1460. [PMID: 36935869 PMCID: PMC10019160 DOI: 10.1097/txd.0000000000001460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/12/2023] [Accepted: 01/28/2023] [Indexed: 03/17/2023] Open
Abstract
New estimated glomerular filtration rate (GFR) equations that do not include a race coefficient have been created to better estimate kidney function, reduce inequities in kidney disease care, and improve the historically limited access to transplantation in African Americans. The impact of these new equations on estimated GFR (eGFR) in living donors pre- and postdonation is not known. Methods To address this, we conducted a single-center retrospective cohort study of 150 kidney donors and donor candidates. We calculated pre- and postdonation eGFR using the old and new equations and compared them with measured GFR by 2.8 mCi Tc-99m diethylene triamine penta-acetic acid clearance (mGFRDTPA) and 24-h creatinine clearance (mGFRCrCl). We evaluated the impact of the new equations on donation eligibility and postdonation eGFR. Results We found that using the new eGFR equations resulted in higher predonation eGFR compared with the old equations but remained significantly lower than mGFRDTPA and mGFRCrCl. We also found that using the new eGFR equations would not exclude any potential donors based on our center's GFR criteria for donation. At 6 mo postdonation, the new equations resulted in higher eGFR values compared with the old equations. Conclusions The new eGFR equations continue to underestimate GFR in healthy donor candidates but would not exclude any potential donors from donation and resulted in higher eGFR predonation and postdonation in a predominantly White population. eGFR equations designed specifically for potential kidney donors are still needed for better kidney function assessment.
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Affiliation(s)
- Ayman Al Jurdi
- Division of Nephrology, Transplant Center, Massachusetts General Hospital, Boston, MA
| | - Kassem Safa
- Division of Nephrology, Transplant Center, Massachusetts General Hospital, Boston, MA
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Laham G, Ponti JP, Soler Pujol G. Assessing Renal Function for Kidney Donation. How Low Is Too Low? Front Med (Lausanne) 2022; 8:784435. [PMID: 35186970 PMCID: PMC8847393 DOI: 10.3389/fmed.2021.784435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/09/2021] [Indexed: 11/13/2022] Open
Abstract
Kidney transplantation (KT) is the treatment of choice for patients with end-stage kidney disease (ESKD) with decreased morbi-mortality, improved life quality, and reduced cost. However, the shortage of organs from deceased donors led to an increase in KT from living donors. Some stipulate that living donors have a higher risk of ESKD after donation compared with healthy non-donors. The reason for this is not clear. It is possible that ESKD is due to the nephrectomy-related reduction in glomerular filtration rate (GFR), followed by an age-related decline that may be more rapid in related donors. It is essential to assess donors properly to avoid rejecting suitable ones and not accepting those with a higher risk of ESKD. GFR is a central aspect of the evaluation of potential donors since there is an association between low GFR and ESKD. The methods for assessing GFR are in continuous debate, and the kidney function thresholds for accepting a donor may vary according to the guidelines. While direct measurements of GFR (mGFR) provide the most accurate evaluation of kidney function, guidelines do not systematically use this measurement as a reference. Also, some studies have shown that the GFR decreases with age and may vary with gender and race, therefore, the lower limit of GFR in patients eligible to donate may vary based on these demographic factors. Finally, it is known that CrCl overestimates mGFR while eGFR underestimates it, therefore, another way to have a reliable GFR could be the combination of two measurement methods.
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Affiliation(s)
- Gustavo Laham
- Internal Medicine Department, Nephrology Section, Centro de Educación Médica e Investigaciones Clínicas Norberto Quirno (CEMIC), Buenos Aires, Argentina
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Marzinke MA, Greene DN, Bossuyt PM, Chambliss AB, Cirrincione LR, McCudden CR, Melanson SEF, Noguez JH, Patel K, Radix AE, Takwoingi Y, Winston-McPherson G, Young BA, Hoenig MP. Limited Evidence for Use of a Black Race Modifier in eGFR Calculations: A Systematic Review. Clin Chem 2021; 68:521-533. [DOI: 10.1093/clinchem/hvab279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/13/2021] [Indexed: 11/13/2022]
Abstract
Abstract
Background
Commonly used estimated glomerular filtration rate (eGFR) equations include a Black race modifier (BRM) that was incorporated during equation derivation. Race is a social construct, and a poorly characterized variable that is applied inconsistently in clinical settings. The BRM results in higher eGFR for any creatinine concentration, implying fundamental differences in creatinine production or excretion in Black individuals compared to other populations. Equations without inclusion of the BRM have the potential to detect kidney disease earlier in patients at the greatest risk of chronic kidney disease (CKD), but also has the potential to over-diagnose CKD or impact downstream clinical interventions. The purpose of this study was to use an evidence- based approach to systematically evaluate the literature relevant to the performance of the eGFR equations with and without the BRM and to examine the clinical impact of the use or removal.
Content
PubMed and Embase databases were searched for studies comparing measured GFR to eGFR in racially diverse adult populations using the Modification of Diet in Renal Disease or the 2009-Chronic Kidney Disease Epidemiology Collaboration-creatinine equations based on standardized creatinine measurements. Additionally, we searched for studies comparing clinical use of eGFR calculated with and without the BRM. 8,632 unique publications were identified; an additional 3 studies were added post-hoc. In total, 96 studies were subjected to further analysis and 44 studies were used to make a final assessment.
Summary
There is limited published evidence to support the use of a BRM in eGFR equations.
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Affiliation(s)
- Mark A Marzinke
- Departments of Pathology and Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dina N Greene
- Department of Laboratory Medicine and Pathology; University of Washington, Seattle, WA; Kaiser Permanente, Renton, WA
| | - Patrick M Bossuyt
- Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | | | | | - Christopher R McCudden
- Department of Pathology and Laboratory Medicine, The Ottawa Hospital; University of Ottawa; Eastern Ontario Regional Laboratory Association, Ottawa, Ontario, Canada
| | - Stacy E F Melanson
- Department of Pathology; Brigham and Women’s Hospital; Harvard Medical School, Boston, MA
| | - Jaime H Noguez
- Department of Pathology, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, OH
| | - Khushbu Patel
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA
| | - Asa E Radix
- Callen-Lorde Community Health Center, New York, NY
| | - Yemisi Takwoingi
- Institute of Applied Health Research,University of Birmingham and NIHR Birmingham Biomedical Research Centre, University Hospitals Birmingham NHS Foundation Trust and University of Birmingham, Birmingham, United Kingdom
| | | | - Bessie A Young
- Office of Healthcare Equity, Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA
| | - Melanie P Hoenig
- Renal Division, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA
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Montgomery JR, Brown CS, Zondlak AN, Walsh KW, Kozlowski JE, Pinsky AM, Herriman EA, Sussman J, Lu Y, Stein EB, Shankar PR, Sung RS, Woodside KJ. CT-measured Cortical Volume Ratio Is an Accurate Alternative to Nuclear Medicine Split Scan Ratio Among Living Kidney Donors. Transplantation 2021; 105:2596-2605. [PMID: 33950636 DOI: 10.1097/tp.0000000000003676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The 125I-iothalamate clearance and 99mTc diethylenetriamine-pentaacetic acid (99mTc-DTPA) split scan nuclear medicine studies are used among living kidney donor candidates to determine measured glomerular filtration rate (mGFR) and split scan ratio (SSR). The computerized tomography-derived cortical volume ratio (CVR) is a novel measurement of split kidney function and can be combined with predonation estimated GFR (eGFR) or mGFR to predict postdonation kidney function. Whether predonation SSR predicts postdonation kidney function better than predonation CVR and whether predonation mGFR provides additional information beyond predonation eGFR are unknown. METHODS We performed a single-center retrospective analysis of 204 patients who underwent kidney donation between June 2015 and March 2019. The primary outcome was 1-y postdonation eGFR. Model bases were created from a measure of predonation kidney function (mGFR or eGFR) multiplied by the proportion that each nondonated kidney contributed to predonation kidney function (SSR or CVR). Multivariable elastic net regression with 1000 repetitions was used to determine the mean and 95% confidence interval of R2, root mean square error (RMSE), and proportion overprediction ≥15 mL/min/1.73 m2 between models. RESULTS In validation cohorts, eGFR-CVR models performed best (R2, 0.547; RMSE, 9.2 mL/min/1.73 m2, proportion overprediction 3.1%), whereas mGFR-SSR models performed worst (R2, 0.360; RMSE, 10.9 mL/min/1.73 m2, proportion overprediction 7.2%) (P < 0.001 for all comparisons). CONCLUSIONS These findings suggest that predonation CVR may serve as an acceptable alternative to SSR during donor evaluation and furthermore, that a model based on CVR and predonation eGFR may be superior to other methods.
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Affiliation(s)
- John R Montgomery
- Department of Surgery, Section of Transplant Surgery, University of Michigan, Ann Arbor, MI
- Center for Healthcare Outcomes & Policy, University of Michigan, Ann Arbor, MI
| | - Craig S Brown
- Department of Surgery, Section of Transplant Surgery, University of Michigan, Ann Arbor, MI
- Center for Healthcare Outcomes & Policy, University of Michigan, Ann Arbor, MI
| | | | - Kevin W Walsh
- Medical School, University of Michigan, Ann Arbor, MI
| | | | | | - Emily A Herriman
- Department of Surgery, Section of Transplant Surgery, University of Michigan, Ann Arbor, MI
| | - Jeremy Sussman
- Division of General Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Yee Lu
- Division of Nephrology, Department of Medicine, University of Michigan, Ann Arbor, MI
| | - Erica B Stein
- Division of Abdominal Radiology, Department of Radiology, University of Michigan, Ann Arbor, MI
| | - Prasad R Shankar
- Division of Abdominal Radiology, Department of Radiology, University of Michigan, Ann Arbor, MI
- Michigan Radiology Quality Collaborative, University of Michigan, Ann Arbor, MI
| | - Randall S Sung
- Department of Surgery, Section of Transplant Surgery, University of Michigan, Ann Arbor, MI
| | - Kenneth J Woodside
- Department of Surgery, Section of Transplant Surgery, University of Michigan, Ann Arbor, MI
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Ebad CA, Brennan D, Chevarria J, Hussein MB, Sexton D, Mulholland D, Doyle C, O'Kelly P, Williams Y, Dunne R, O'Seaghdha C, Little D, Morrin M, Conlon PJ. Is Bigger Better? Living Donor Kidney Volume as Measured by the Donor CT Angiogram in Predicting Donor and Recipient eGFR after Living Donor Kidney Transplantation. J Transplant 2021; 2021:8885354. [PMID: 34336253 PMCID: PMC8286185 DOI: 10.1155/2021/8885354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 06/30/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The role of kidney volume measurement in predicting the donor and recipient kidney function is not clear. METHODS We measured kidney volume bilaterally in living kidney donors using CT angiography and assessed the association with the donor remaining kidney and recipient kidney (donated kidney) function at 1 year after kidney transplantation. Donor volume was categorized into tertiles based on lowest, middle, and highest volume. RESULTS There were 166 living donor and recipient pairs. The mean donor age was 44.8 years (SD ± 10.8), and donor mean BMI was 25.5 (SD ± 2.9). The recipients of living donor kidneys were 64% male and had a mean age of 43.5 years (SD ± 13.3). Six percent of patients experienced an episode of cellular rejection and were maintained on dialysis for a mean of 18 months (13-32) prior to transplant. Kidney volume was divided into tertiles based on lowest, middle, and highest volume. Kidney volume median (range) in tertiles 1, 2, and 3 was 124 (89-135 ml), 155 (136-164 ml), and 184 (165-240 ml) with donor eGFR ml/min (adjusted for body surface area expressed as ml/min/1.73 m2) at the time of donation in each tertile, 109 (93-129), 110 (92-132), and 101 ml/min (84-117). The median (IQR) eGFR in tertiles 1 to 3 in kidney recipients at 1 year after donation was 54 (44-67), 62 (50-75), and 63 ml/min (58-79), respectively. The median (IQR) eGFR in tertiles 1 to 3 in the remaining kidney of donors at 1 year after donation was 59 (53-66), 65 (57-72), and 65 ml/min (56-73), respectively. CONCLUSION Bigger kidney volume was associated with better eGFR at 1 year after transplant in the recipient and marginally in the donor remaining kidney.
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Affiliation(s)
- Chaudhry Adeel Ebad
- Department of Nephrology and Kidney Transplantation, Beaumont Hospital, Dublin, Ireland
| | - David Brennan
- Department of Radiology, Beaumont Hospital, Dublin, Ireland
| | - Julio Chevarria
- Department of Nephrology and Kidney Transplantation, Beaumont Hospital, Dublin, Ireland
| | - Mohammad Bin Hussein
- Department of Nephrology and Kidney Transplantation, Beaumont Hospital, Dublin, Ireland
| | - Donal Sexton
- Department of Nephrology and Kidney Transplantation, Beaumont Hospital, Dublin, Ireland
| | | | - Ciaran Doyle
- Department of Nephrology and Kidney Transplantation, Beaumont Hospital, Dublin, Ireland
| | - Patrick O'Kelly
- Department of Nephrology and Kidney Transplantation, Beaumont Hospital, Dublin, Ireland
| | - Yvonne Williams
- Department of Nephrology and Kidney Transplantation, Beaumont Hospital, Dublin, Ireland
| | - Ruth Dunne
- Department of Radiology, Beaumont Hospital, Dublin, Ireland
| | - Conall O'Seaghdha
- Department of Nephrology and Kidney Transplantation, Beaumont Hospital, Dublin, Ireland
| | - Dilly Little
- Department of Urology and Kidney Transplantation, Beaumont Hospital, Dublin, Ireland
| | - Martina Morrin
- Department of Radiology, Beaumont Hospital, Dublin, Ireland
| | - Peter J. Conlon
- Department of Nephrology and Kidney Transplantation, Beaumont Hospital, Dublin, Ireland
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Garg N, Poggio ED, Mandelbrot D. The Evaluation of Kidney Function in Living Kidney Donor Candidates. KIDNEY360 2021; 2:1523-1530. [PMID: 35373109 PMCID: PMC8786144 DOI: 10.34067/kid.0003052021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/28/2021] [Indexed: 02/04/2023]
Abstract
Living kidney donors incur a small increased risk of ESKD, of which predonation GFR is an important determinant. As a result, kidney function assessment is central to the donor candidate evaluation and selection process. This article reviews the different methods of GFR assessment, including eGFR, creatinine clearance, and measured GFR, and the current guidelines on GFR thresholds for donor acceptance. eGFR obtained using the 2009 CKD Epidemiology Collaboration equation that, although the best of estimating estimations, tends to underestimate levels and has limited accuracy, especially near-normal GFR values. In the United States, the Organ Procurement and Transplantation Network policy on living donation mandates either measured GFR or creatinine clearance as part of the evaluation. Measured GFR is considered the gold standard, although there is some variation in performance characteristics, depending on the marker and technique used. Major limitations of creatinine clearance are dependency on accuracy of timed collection, and overestimation as a result of distal tubular creatinine secretion. GFR declines with healthy aging, and most international guidelines recommend use of age-adapted selection criteria. The 2017 Kidney Disease: Improving Global Outcomes Guideline for the Evaluation and Care of Living Kidney Donors diverges from other guidelines and recommends using absolute cutoff of <60 ml/min per 1.73m2 for exclusion and ≥90 ml/min per 1.73m2 for acceptance, and determination of candidacy with intermediate GFR on the basis of long-term ESKD risk. However, several concerns exist for this strategy, including inappropriate acceptance of younger candidates due to underestimation of risk, and exclusion of older candidates whose kidney function is in fact appropriate for age. The role of cystatin C and other newer biomarkers, and data on the effect of predonation GFR on not just ESKD risk, but also advanced CKD risk and cardiovascular outcomes are needed.
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Affiliation(s)
- Neetika Garg
- Division of Nephrology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Emilio D. Poggio
- Department of Nephrology and Hypertension, Cleveland Clinic, Cleveland, Ohio
| | - Didier Mandelbrot
- Division of Nephrology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
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