Association of BKV viremia and nephropathy with adverse alloimmune outcomes in kidney transplant recipients.

BACKGROUND: Immunosuppression reduction for BK polyoma virus (BKV) must be balanced against risk of adverse alloimmune outcomes. We sought to characterize risk of alloimmune events after BKV within context of HLA-DR/DQ molecular mismatch (mMM) risk score. METHODS: This single-center study evaluated 460 kidney transplant patients on tacrolimus-mycophenolate-prednisone from 2010-2021. BKV status was classified at 6-months post-transplant as "BKV" or "no BKV" in landmark analysis. Primary outcome was T-cell mediated rejection (TCMR). Secondary outcomes included all-cause graft failure (ACGF), death-censored graft failure (DCGF), de novo donor specific antibody (dnDSA), and antibody-mediated rejection (ABMR). Predictors of outcomes were assessed in Cox proportional hazards models including BKV status and alloimmune risk defined by recipient age and molecular mismatch (RAMM) groups. RESULTS: At 6-months post-transplant, 72 patients had BKV and 388 had no BKV. TCMR occurred in 86 recipients, including 27.8% with BKV and 17% with no BKV (p = .05). TCMR risk was increased in recipients with BKV (HR 1.90, (95% CI 1.14, 3.17); p = .01) and high vs. low-risk RAMM group risk (HR 2.26 (95% CI 1.02, 4.98); p = .02) in multivariable analyses; but not HLA serological MM in sensitivity analysis. Recipients with BKV experienced increased dnDSA in univariable analysis, and there was no association with ABMR, DCGF, or ACGF. CONCLUSIONS: Recipients with BKV had increased risk of TCMR independent of induction immunosuppression and conventional alloimmune risk measures. Recipients with high-risk RAMM experienced increased TCMR risk. Future studies on optimizing immunosuppression for BKV should explore nuanced risk stratification and may consider novel measures of alloimmune risk.

Trends and predictors of changes in renal function after radical nephrectomy for renal tumours.

BACKGROUND: Chronic kidney disease (CKD) is a common postoperative complication in patients who undergo radical nephrectomy for renal tumours. However, the factors influencing long-term renal function require further investigation. OBJECTIVE: This study was designed to investigate the trends in renal function changes and risk factors for renal function deterioration in renal tumour patients after radical nephrectomy. METHODS: We monitored changes in renal function before and after surgery for 3 years. The progression of renal function was determined by the progression and degradation of CKD stages. Univariate and multivariate logistic regression analyses were used to analyse the causes of renal function progression. RESULTS: We analysed the data of 329 patients with renal tumours who underwent radical nephrectomies between January 2013 and December 2018. In this study, 43.7% of patients had postoperative acute kidney injury (AKI), and 48.3% had CKD at advanced stages. Further research revealed that patients' renal function stabilized 3 months after surgery. Additionally, renal function changes during these 3 months have a substantial impact on the progression of long-term renal function changes in patients. CONCLUSION: AKI may be an indicator of short-term postoperative changes in renal function. Renal function tests should be performed in patients with AKI after radical nephrectomy to monitor the progression of functional impairment, particularly within the first 3 months after radical nephrectomy.

Surgical complications and technical failure of simultaneous pancreas-kidney transplantation: A 22-year experience from a single center.

Simultaneous pancreas-kidney transplantation (SPKT) is the best treatment for selected individuals with type 1 diabetes mellitus and end-stage renal disease. Despite advances in surgical techniques, donor and recipient selection, and immunosuppressive therapies, SPKT remains a complex procedure with associated surgical complications and adverse consequences. We conducted a retrospective study that included 263 SPKT procedures performed between May 2000, and December 2022. A total of 65 patients (25%) required at least one relaparotomy, resulting in an all-cause relaparotomy rate of 2.04 events per 100 in-hospital days. Lower donor body mass index was identified as an independent factor associated with reoperation (OR .815; 95% CI:  .725-.917, p = .001). Technical failure (TF) occurred in 9.9% of cases, primarily attributed to pancreas graft thrombosis, intra-abdominal infections, bleeding, and anastomotic leaks. Independent predictors of TF at 90 days included donor age above 36 years (HR 2.513; 95% CI 1.162-5.434), previous peritoneal dialysis (HR 2.503; 95% CI 1.149-5.451), and specific pancreas graft reinterventions. The findings highlight the importance of carefully considering donor and recipient factors in SPKT. The incidence of TF in our study population aligns with the recent series. Continuous efforts should focus on identifying and mitigating potential risk factors to enhance SPKT outcomes, thereby reducing post-transplant complications.

Impact of hyperparathyroidism on allograft histology and function after kidney transplantation: Rethinking its causal role in graft dysfunction.

INTRODUCTION: The causal relationship between hyperparathyroidism and kidney graft dysfunction remains inconclusive. Applying Bradford-Hill's temporality and consistency causation principles, we assessed the effect of parathyroid hormone (iPTH) on graft histology and eGFR trajectory on kidney transplant recipients (KTRs) with normal time-zero graft biopsies. METHODS: Retrospective cohort study evaluating the effect of hyperparathyroidism on interstitial fibrosis and tubular atrophy (IF/TA) development in 1232 graft biopsies. Pre-transplant hyperparathyroidism was categorized by KDIGO or KDOQI criteria, and post-transplant hyperparathyroidism by iPTH >1× and >2× the URL 1 year after transplantation. RESULTS: We included 325 KTRs (56% female, age 38 ± 13 years, follow-up 4.2 years [IQR: 2.7-5.8]). Based on pre-transplant iPTH levels, 26% and 66% exceeded the KDIGO and KDOQI targets, respectively. There were no significant differences in the development of >25% IF/TA between KTRs with pre-transplant iPTH levels above and within target range according to KDIGO (53% vs. 62%, P = .16, HR.94 [95% CI:.67-1.32]) and KDOQI (60% vs. 60%, P = 1.0, HR 1.19 [95% CI:.88-1.60]) criteria. Similarly, there were no differences when using 1 year post-transplant iPTH cut-offs > 88 pg/mL (58% vs. 64%, P = .33) and > 176 pg/mL (55% vs. 62%, P = .19). After adjusting for confounders, no significant differences were observed in eGFR trajectories among the iPTH strata. CONCLUSION: In young KTRs who received a healthy graft, no association was found between increased pre- and post-transplant iPTH levels and graft dysfunction, as assessed histologically and through eGFR trajectory. The concept of hyperparathyroidism as a risk factor for graft dysfunction in recipients at low risk requires reevaluation.

Efficacy of Flexible Ureteroscopy Lithotripsy and Percutaneous Nephrolithotomy in the Treatment of Patients with Kidney Stones and Their Impact on Inflammatory Response and Renal Function.

BACKGROUND: Kidney stones are one of the most common benign diseases in urology. As technology updates and iterates, more minimally invasive and laparoscopic surgeries with higher safety performance appear. This paper explores the effectiveness of retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PCNL) in treating kidney stones, focusing on their effects on inflammatory responses and renal function. METHODS: We conducted a retrospective analysis of 200 patients with kidney stones treated in our hospital between June 2019 and June 2023. 100 patients who underwent RIRS were included in the RIRS group. Another 100 patients who underwent PCNL treatment were included in the PCNL group. The intraoperative blood loss, operation duration, and hospitalization time of the two groups of patients were recorded and compared. The enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of inflammatory factors in the serum of the two groups of patients: [serum amyloid A (SAA), interleukin-6 (IL-6) and high-sensitivity C-reactive protein (CRP)] and renal function index [blood urea nitrogen (BUN), creatinine (Scr) and serum cystatin (Cys-c)]. The two groups of patients were recorded separately: Postoperative complications and stone-free rate. RESULTS: Operation duration was longer for the RIRS group than the PCNL group, which exhibited significantly less intraoperative blood loss and shorter hospital stays (p < 0.05). Before surgery, there was no statistically significant difference in the serum levels of SAA, IL-6, and CRP between the two groups of patients (p > 0.05). On the first day after surgery, the serum SAA levels in both groups were lower than before surgery, IL-6 and CRP levels were higher than before surgery, and the serum levels of SAA, IL-6, and CRP in the RIRS group were significantly lower than those in the PCNL group. The difference was statistically significant (p < 0.05). Before surgery, there was no statistically significant difference in the serum BUN, Scr, and Cys-c levels between the two groups of patients (p > 0.05). On the first day after surgery, the serum BUN, Scr, and Cys-c levels of the two groups of patients were significantly higher than those before surgery. The serum BUN, Scr, and Cys-c levels of the RIRS group were significantly lower than those of the PCNL group, and the difference was statistically significant (p < 0.05). Both surgical methods have sound stone-clearing effects regarding long-term stone clearance rates 1 month and 3 months after surgery (p > 0.05). PCNL had a better stone clearance rate on the 2nd postoperative day (p < 0.05). The incidence of postoperative complications in the RIRS group was significantly lower than that in the PCNL group, and the difference was statistically significant (p < 0.05). CONCLUSION: For kidney stones ≤2 cm, PCNL showed higher stone clearance rates on the second postoperative day. However, RIRS and PCNL demonstrated adequate long-term stone clearance at 1 and 3 months post-surgery. Both surgical methods are safe and effective, and RIRS is safer than PCNL. Compared with PCNL, RIRS is a new method of kidney stone operation, which has less trauma to the patient's body and fewer complications after the operation, speeding up the recovery process of the patient.

Assessment of epidemiology and outcomes of adult patients with kidney-limited thrombotic microangiopathies.

Thrombotic microangiopathies (TMA) are usually associated with hematological features (RH-TMA). The epidemiology of TMA limited to kidneys (RL-TMA) is unclear Therefore, patients with TMA and native kidney biopsies were identified during 2009-2022 in 20 French hospitals and results evaluated. RL-TMA was present in 341/757 (45%) patients and associated with lower creatinine levels (median 184 vs 346 µmol/L) than RH-TMA. RL-TMA resulted from virtually all identified causes, more frequently from anti-VEGF treatment and hematological malignancies but less frequently from shigatoxin-associated hemolytic uremic syndrome (HUS), systemic sclerosis, gemcitabine and bacterial infection, and even less frequently when three or more causes/triggers were combined (RL-TMA: 5%; RH-TMA: 12%). RL-TMA was associated with significantly lower major cardiovascular events (10% vs 20%), kidney replacement therapy (23% vs 43%) and death (12% vs 20%) than RH-TMA during follow-up (median 28 months). Atypical HUS (aHUS) was found in 326 patients (RL-TMA: 43%, RH-TMA: 44%). Among the 69 patients with proven complement-mediated aHUS, eculizumab (anti-C5 therapy) was used in 43 (62%) (RL-TMA: 35%; RH-TMA: 71%). Among the 257 other patients with aHUS, including 51% with RL-TMA, eculizumab was used in 29 but with unclear effects of this treatment. Thus, RL-TMA represents a very high proportion of patients with TMA and results from virtually all known causes of TMA and includes 25% of patients with complement-mediated aHUS. Adverse outcomes of RL-TMA are lower compared to RH-TMA but remain significant. Anti-C5 therapy was rarely used in RL-TMA, even in proven complement-mediated aHUS, and its effects remain to be assessed.

Toward Equitable Kidney Function Estimation in Critical Care Practice: Guidance From the Society of Critical Care Medicine's Diversity, Equity, and Inclusion in Renal Clinical Practice Task Force.

OBJECTIVES: Accurate glomerular filtration rate (GFR) assessment is essential in critically ill patients. GFR is often estimated using creatinine-based equations, which require surrogates for muscle mass such as age and sex. Race has also been included in GFR equations, based on the assumption that Black individuals have genetically determined higher muscle mass. However, race-based GFR estimation has been questioned with the recognition that race is a poor surrogate for genetic ancestry, and racial health disparities are driven largely by socioeconomic factors. The American Society of Nephrology and the National Kidney Foundation (ASN/NKF) recommend widespread adoption of new "race-free" creatinine equations, and increased use of cystatin C as a race-agnostic GFR biomarker. DATA SOURCES: Literature review and expert consensus. STUDY SELECTION: English language publications evaluating GFR assessment and racial disparities. DATA EXTRACTION: We provide an overview of the ASN/NKF recommendations. We then apply an Implementation science methodology to identify facilitators and barriers to implementation of the ASN/NKF recommendations into critical care settings and identify evidence-based implementation strategies. Last, we highlight research priorities for advancing GFR estimation in critically ill patients. DATA SYNTHESIS: Implementation of the new creatinine-based GFR equation is facilitated by low cost and relative ease of incorporation into electronic health records. The key barrier to implementation is a lack of direct evidence in critically ill patients. Additional barriers to implementing cystatin C-based GFR estimation include higher cost and lack of test availability in most laboratories. Further, cystatin C concentrations are influenced by inflammation, which complicates interpretation. CONCLUSIONS: The lack of direct evidence in critically ill patients is a key barrier to broad implementation of newly developed "race-free" GFR equations. Additional research evaluating GFR equations in critically ill patients and novel approaches to dynamic kidney function estimation is required to advance equitable GFR assessment in this vulnerable population.

Acute glomerulonephritis with concurrent suspected bacterial pneumonia - is it the tip of the iceberg?

BACKGROUND: Post infectious glomerulonephritis is the most common glomerulopathy in children, occurring several weeks after nephritogenic streptococcal throat or skin infection. Reports of acute glomerulonephritis (AGN) occurring during active bacterial pneumonia in children are rare. The aim of this study was to evaluate the incidence of AGN concurrent with bacterial pneumonia in children. METHODS: We reviewed records of all children admitted with a diagnosis of pneumonia to the pediatric department in a single tertiary medical center between January 2015 and April 2023. Patients with bacterial pneumonia and concurrent glomerulonephritis were included. RESULTS: Eleven (0.98%) of 1,123 patients with bacterial pneumonia had concurrent AGN. All were males with a median age of 2.7 years (range 1-13). Mean time from bacterial pneumonia onset to acute glomerulonephritis symptoms was 2.7 ± 1.5 days. Five (45%) patients had evidence of pneumococcal infection. Hypertension was found in 10 (91%) patients. Mean trough eGFR was 43.5 ± 21.4 ml/min/1.73 m2 (range 11-73). Ten patients (91%) had low C3 levels. Median urinary protein-to-creatinine ratio was 2.5 mg/mg (IQR 2.15-14.75). All patients fully recovered. Microscopic hematuria was the last finding to normalize after a median of 29.5 days (IQR 17.25-38). CONCLUSION: AGN during bacterial pneumonia may be more frequent than previously recognized. Kidney prognosis was excellent in all patients. Prospective studies are needed to evaluate the impact of this condition.

Real world evaluation of kidney failure risk equations in predicting progression from chronic kidney disease to kidney failure in an Australian cohort.

BACKGROUND: Chronic kidney disease progression to kidney failure is diverse, and progression may be different according to genetic aspects and settings of care. We aimed to describe kidney failure risk equation prognostic accuracy in an Australian population. METHODS: A retrospective cohort study was undertaken in a public hospital community-based chronic kidney disease service in Brisbane, Australia, which included a cohort of 406 adult patients with chronic kidney disease Stages 3-4 followed up over 5 years (1/1/13-1/1/18). Risk of progression to kidney failure at baseline using Kidney Failure Risk Equation models with three (eGFR/age/sex), four (add urinary-ACR) and eight variables (add serum-albumin/phosphate/bicarbonate/calcium) at 5 and 2 years were compared to actual patient outcomes. RESULTS: Of 406 patients followed up over 5 years, 71 (17.5%) developed kidney failure, while 112 died before reaching kidney failure. The overall mean difference between observed and predicted risk was 0.51% (p = 0.659), 0.93% (p = 0.602), and - 0.03% (p = 0.967) for the three-, four- and eight-variable models, respectively. There was small improvement in the receiver operating characteristic-area under the curve from three-variable to four-variable models: 0.888 (95%CI = 0.819-0.957) versus 0.916 (95%CI = 0.847-0.985). The eight-variable model showed marginal receiver operating characteristic-area under the curve improvement: 0.916 (95%CI = 0.847-0.985) versus 0.922 (95%CI = 0.853-0.991). The results were similar in predicting 2 year risk of kidney failure. CONCLUSIONS: The kidney failure risk equation accurately predicted progression to kidney failure in an Australian chronic kidney disease population. Younger age, male sex, lower estimated glomerular filtration rate, higher albuminuria, diabetes mellitus, tobacco smoking and non-Caucasian ethnicity were associated with increased risk of kidney failure. Cause-specific cumulative incidence function for progression to kidney failure or death, stratified by chronic kidney disease stage, demonstrated differences within different chronic kidney disease stages, highlighting the interaction between comorbidity and outcome.

Assessing the status of European laboratories in evaluating biomarkers for chronic kidney diseases (CKD) and recommendations for improvement: insights from the 2022 EFLM Task Group on CKD survey.

OBJECTIVES: Chronic kidney disease (CKD) is a global health issue, ranking as the third leading cause of death worldwide. CKD diagnosis and management depend on clinical laboratory tests, necessitating consistency for precise patient care. Global harmonization of CKD testing through clinical practice guidelines (CPGs) is recommended. Prior to CPG development, assessing the current CKD testing landscape is crucial. In 2022, the European Federation of Laboratory Medicine (EFLM) conducted an online survey among European laboratories associated with EFLM, evaluating CKD testing practices, including new glomerular filtration rate (GFR) estimation methods. This report summarizes the 2022 survey findings and offers recommendations for improving CKD test standardization. METHODS: An online survey was conducted in November 2022 using a questionnaire hosted on LimeSurvey sent to European laboratories affiliated with the EFLM. The survey results were recorded in Excel files and analysed. RESULTS: The results highlight significant discrepancies among countries in unit expression, methods, cystatin C use, and GFR calculation equations. Additionally, limited attention to pediatric renal biology specifics, varied proteinuria and albuminuria result expressions, and limited awareness of GFR measurement methods through iohexol clearance are noted. CONCLUSIONS: In an effort to enhance the standardization of crucial biomarkers utilized in nephrology for evaluating renal function and diagnosing kidney injuries, the EFLM Task Group on CKD suggests nine practical recommendations tailored for European laboratories. The group is confident that implementing these measures will minimize result expression discrepancies, ultimately leading to enhanced patient care.

Noninvasive Assessment of Diabetic Kidney Disease With MRI: Hype or Hope?

Owing to the increasing prevalence of diabetic mellitus, diabetic kidney disease (DKD) is presently the leading cause of chronic kidney disease and end-stage renal disease worldwide. Early identification and disease interception is of paramount clinical importance for DKD management. However, current diagnostic, disease monitoring and prognostic tools are not satisfactory, due to their low sensitivity, low specificity, or invasiveness. Magnetic resonance imaging (MRI) is noninvasive and offers a host of contrast mechanisms that are sensitive to pathophysiological changes and risk factors associated with DKD. MRI tissue characterization involves structural and functional information including renal morphology (kidney volume (TKV) and parenchyma thickness using T1- or T2-weighted MRI), renal microstructure (diffusion weighted imaging, DWI), renal tissue oxygenation (blood oxygenation level dependent MRI, BOLD), renal hemodynamics (arterial spin labeling and phase contrast MRI), fibrosis (DWI) and abdominal or perirenal fat fraction (Dixon MRI). Recent (pre)clinical studies demonstrated the feasibility and potential value of DKD evaluation with MRI. Recognizing this opportunity, this review outlines key concepts and current trends in renal MRI technology for furthering our understanding of the mechanisms underlying DKD and for supplementing clinical decision-making in DKD. Progress in preclinical MRI of DKD is surveyed, and challenges for clinical translation of renal MRI are discussed. Future directions of DKD assessment and renal tissue characterization with (multi)parametric MRI are explored. Opportunities for discovery and clinical break-through are discussed including biological validation of the MRI findings, large-scale population studies, standardization of DKD protocols, the synergistic connection with data science to advance comprehensive texture analysis, and the development of smart and automatic data analysis and data visualization tools to further the concepts of virtual biopsy and personalized DKD precision medicine. We hope that this review will convey this vision and inspire the reader to become pioneers in noninvasive assessment and management of DKD with MRI. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 2.

Predictors of augmented renal clearance based on iohexol plasma clearance in critically ill children.

BACKGROUND: Augmented renal clearance (ARC) holds a risk of subtherapeutic drug concentrations. Knowledge of patient-, disease-, and therapy-related factors associated with ARC would allow predicting which patients would benefit from intensified dosing regimens. This study aimed to identify ARC predictors and to describe ARC time-course in critically ill children, using iohexol plasma clearance (CLiohexol) to measure glomerular filtration rate (GFR). METHODS: This is a retrospective analysis of data from the "IOHEXOL" study which validated GFR estimating formulas (eGFR) against CLiohexol. Critically ill children with normal serum creatinine were included, and CLiohexol was performed as soon as possible after pediatric intensive care unit (PICU) admission (CLiohexol1) and repeated (CLiohexol2) after 48-72 h whenever possible. ARC was defined as CLiohexol exceeding normal GFR for age plus two standard deviations. RESULTS: Eighty-five patients were included; 57% were postoperative patients. Median CLiohexol1 was 122 mL/min/1.73 m2 (IQR 75-152). Forty patients (47%) expressed ARC on CLiohexol1. Major surgery other than cardiac surgery and eGFR were found as independent predictors of ARC. An eGFR cut-off value of 99 mL/min/1.73 m2 and 140 mL/min/1.73 m2 was suggested to identify ARC in children under and above 2 years, respectively. ARC showed a tendency to persist on CLiohexol2. CONCLUSIONS: Our findings raise PICU clinician awareness about increased risk for ARC after major surgery and in patients with eGFR above age-specific thresholds. This knowledge enables identification of patients with an ARC risk profile who would potentially benefit from a dose increase at initiation of treatment to avoid underexposure. TRIAL REGISTRATION: ClinicalTrials.gov NCT05179564, registered retrospectively on January 5, 2022.

The Current State of Nuclear Nephrology in Modern Medicine.

Glomerular filtration rate (GFR) is the most reliable parameter of renal function. Regarding the complexity of the gold standard inulin clearance, different estimating equations have been developed with CKD-EPI creatinine equation recommended as the most reliable one. In some clinical situations where creatinine based equations might not be valid, alternative methods are needed. Nuclear medicine methods for measuring GFR with 51Cr EDTA and 99mTc DTPA have been widely used for decades. There are different methodologies for the measurement of kidney function with radiopharmaceuticals: urinary clearance, plasma clearance, multiple plasma sampling, slope intercept, single sample plasma equation, slope only, and the gamma camera-based method. Greater precision of measuring GFR is needed in certain clinical situations. The most common are diagnosis and follow up of chronic kidney disease and definition of the beginning of replacement therapy. The assessment of renal function is also important for potential kidney donors. In recent years, with the introduction of new chemotherapeutic drugs and targeted therapy, oncologic patients treated with nephrotoxic drugs have become more commonly referred for measuring GFR. The monitoring of renal function is important during treatment in order to detect the transformation from reversible acute kidney injury to irreversible chronic kidney disease as well as in the cases of renal insufficiency reduce the dosage and prevent accumulation of the drug and avoid dosage related toxic effects. Assessment of kidney function using measured mGFR will be an important milestone in the creation of more accurate and expanding personalized medicine principle in current onconephrology practice.

Large Bladder Stone Detected on Renal Scintigraphy.

ABSTRACT: A 39-year-old woman with hydronephrosis underwent 99mTc-DTPA renal dynamic scintigraphy to evaluate renal function. The images revealed a central photopenic region in the urinary bladder. SPECT/CT images suggested the abnormal tracer distribution corresponding to a large urinary bladder stone.

Estimated glomerular filtration rate from the renal hypothermia trial: clinical implications.

OBJECTIVE: To assess if estimated glomerular filtration rate (eGFR) can replace measured GFR (mGFR) in partial nephrectomy (PN) trials, using data from a randomised clinical trial. PATIENTS AND METHODS: We conducted a post hoc analysis of the renal hypothermia trial. Patients underwent mGFR with diethylenetriaminepentaacetic acid (DTPA) plasma clearance preoperatively and 1 year after PN. The eGFR was calculated using the 2009 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine equations incorporating age and sex, with and without race: 2009 eGFRcr(ASR) and 2009 eGFRcr(AS), and the 2021 equation that only incorporates age and sex: 2021 eGFRcr(AS). Performance was evaluated by determining the median bias, precision (interquartile range [IQR] of median bias), and accuracy (percentage of eGFR within 30% of mGFR). RESULTS: Overall, 183 patients were included. Pre- and postoperative median bias and precision were similar between the 2009 eGFRcr(ASR) (-0.2 mL/min/1.73 m2 , 95% confidence interval [CI] -2.2 to 1.7, IQR 18.8; and -2.9, 95% CI -5.1 to -1.5, IQR 15, respectively) and 2009 eGFRcr(AS) (-0.3 mL/min/1.73 m2 , 95% CI -2.4 to 1.5, IQR 18.8; and -3.0, 95% CI -5.7 to -1.7, IQR 15.0, respectively). Bias and precision were worse for the 2021 eGFRcr(AS) (-8.8 mL/min/1.73 m2 , 95% CI -10.9 to -6.3, IQR 24.7; and -12.0, 95% CI -15.8 to -8.9, IQR 23.5, respectively). Similarly, pre- and postoperative accuracy was >90% for the 2009 eGFRcr(ASR) and 2009 eGFRcr(AS) equations. Accuracy was 78.6% preoperatively and 66.5% postoperatively for 2021 eGFRcr(AS). CONCLUSION: The 2009 eGFRcr(AS) can accurately estimate GFR in PN trials and could be used instead of mGFR to reduce cost and patient burden.