Race Adjustment in eGFR Equations Does Not Improve Estimation of Acute Kidney Injury Events in Patients with Cirrhosis

The Impact of Health Care Algorithms on Racial and Ethnic Disparities : A Systematic Review

BACKGROUND

There is increasing concern for the potential impact of health care algorithms on racial and ethnic disparities.

PURPOSE

To examine the evidence on how health care algorithms and associated mitigation strategies affect racial and ethnic disparities.

DATA SOURCES

Several databases were searched for relevant studies published from 1 January 2011 to 30 September 2023.

STUDY SELECTION

Using predefined criteria and dual review, studies were screened and selected to determine: 1) the effect of algorithms on racial and ethnic disparities in health and health care outcomes and 2) the effect of strategies or approaches to mitigate racial and ethnic bias in the development, validation, dissemination, and implementation of algorithms.

DATA EXTRACTION

Outcomes of interest (that is, access to health care, quality of care, and health outcomes) were extracted with risk-of-bias assessment using the ROBINS-I (Risk Of Bias In Non-randomised Studies - of Interventions) tool and adapted CARE-CPM (Critical Appraisal for Racial and Ethnic Equity in Clinical Prediction Models) equity extension.

DATA SYNTHESIS

Sixty-three studies (51 modeling, 4 retrospective, 2 prospective, 5 prepost studies, and 1 randomized controlled trial) were included. Heterogenous evidence on algorithms was found to: a) reduce disparities (for example, the revised kidney allocation system), b) perpetuate or exacerbate disparities (for example, severity-of-illness scores applied to critical care resource allocation), and/or c) have no statistically significant effect on select outcomes (for example, the HEART Pathway [history, electrocardiogram, age, risk factors, and troponin]). To mitigate disparities, 7 strategies were identified: removing an input variable, replacing a variable, adding race, adding a non-race-based variable, changing the racial and ethnic composition of the population used in model development, creating separate thresholds for subpopulations, and modifying algorithmic analytic techniques.

LIMITATION

Results are mostly based on modeling studies and may be highly context-specific.

CONCLUSION

Algorithms can mitigate, perpetuate, and exacerbate racial and ethnic disparities, regardless of the explicit use of race and ethnicity, but evidence is heterogeneous. Intentionality and implementation of the algorithm can impact the effect on disparities, and there may be tradeoffs in outcomes.

PRIMARY FUNDING SOURCE

Agency for Healthcare Quality and Research.

Update on Assessment of Estimated Glomerular Filtration Rate in Patients With Cirrhosis

Kidney disease is associated with adverse outcomes in patients with cirrhosis including increased post-liver transplantation (LT) mortality. Therefore, diagnosis and staging of kidney disease are critical to timely implementation of treatment and have important implications for transplant eligibility. Serum creatinine (sCr) is a key component of the Model for End-Stage Liver Disease score in LT candidates, and sCr-based estimated glomerular filtration rate (eGFR) values play an important role in determining medical urgency for LT. However, the use of sCr to assess kidney function may be limited in the cirrhotic milieu due to decreased creatinine production, interference of bilirubin with some laboratory assays for sCr, and expansion of the volume of distribution of creatinine. Therefore, conventional eGFR equations perform poorly in patients with cirrhosis and may overestimate kidney function leading to delayed diagnosis of acute kidney injury or lower priority for LT in patients with a truly low glomerular filtration rate. In this review, we will provide an update on the use of sCr for diagnosis and staging of kidney disease in patients with cirrhosis, discuss the limitations of sCr-based eGFR equations, and discuss novel eGFR equations that have been developed in patients with cirrhosis.

Impact of Race-Adjusted Glomerular Filtration Rate Estimation on Eligibility for Simultaneous Liver-Kidney Transplantation

Estimated glomerular filtration rate (eGFR) is adjusted for Black race in commonly used formulas. This has potential implications for access to simultaneous liver-kidney transplantation (SLKT) as qualifying criteria rely on eGFR. We performed a retrospective study of United Network for Organ Sharing national transplant registry data between February 28, 2002, and March 31, 2019, to evaluate the proportion of Black patients who would be reclassified as meeting SLKT criteria (as defined per current policies) if race adjustment were removed from 2 prominent eGFR equations (Modification of Diet in Renal Disease-4 [MDRD-4] and Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]). Of the 7937 Black patients listed for transplant during the study period, we found that 3.6% would have been reclassified as qualifying for chronic kidney disease (CKD)-related SLKT with removal of race adjustment for MDRD-4, and 3.0% would have been reclassified with CKD-EPI; this represented 23.7% and 18.7% increases in SLKT candidacy, respectively. Reclassification impacted women more than men (eg, 4.5% versus 3.0% by MDRD-4; P < 0.05). In an exploratory analysis, patients meeting SLKT criteria by race-unadjusted eGFR equations were significantly more likely to receive liver transplantation alone (LTA) compared with SLKT. Approximately 2.0% of reclassified patients required kidney transplantation within 1 year of LTA versus 0.3% of nonreclassified patients. In conclusion, race adjustment in eGFR equations may impact SLKT candidacy for 3.0% to 4.0% of Black patients listed for LTA overall. Approximately 2.0% of patients reclassified as meeting SLKT criteria require short-term post-LTA kidney transplantation. These data argue for developing novel algorithms for glomerular filtration rate estimation free of race to promote equity.

Limited Evidence for Use of a Black Race Modifier in eGFR Calculations: A Systematic Review

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.

Advances in management of hepatorenal syndrome

PURPOSE OF REVIEW

Hepatorenal syndrome (HRS) is encountered frequently in patients with end-stage liver disease and remains an important cause of morbidity and mortality in this patient population. This review will focus and provide updates on pathophysiology, assessment of kidney function, new definitions, and treatment and prevention of HRS.

RECENT FINDINGS

Pathophysiology of HRS has been elucidated more recently and in addition to hemodynamic changes, the role of systemic inflammatory response contributes significantly to this process. Assessment of kidney function in patients with liver cirrhosis remains challenging. Novel glomerular filtration rate equations have been developed in patients with liver disease to better estimate kidney function and changes made in the definition of acute kidney injury (AKI), which are more aligned with KDIGO criteria for AKI. Vasoconstrictors, especially terlipressin, along with albumin remain the mainstay of pharmacological treatment of HRS-AKI. Biomarkers have been useful in differentiating ATN from HRS at an early stage.

SUMMARY

HRS remains a significant cause of morbidity and mortality for patients with end-stage liver disease. Newer understanding of mechanisms in development and pathophysiology of HRS have helped with elucidation of the disease process.