Assessing trends and variability in outpatient dual testing for chronic kidney disease with urine albumin and serum creatinine, 2009-2018: a retrospective cohort study in the Veterans Health Administration System.

BACKGROUND: Simultaneous urine testing for albumin (UAlb) and serum creatinine (SCr), that is, 'dual testing,' is an accepted quality measure in the management of diabetes. As chronic kidney disease (CKD) is defined by both UAlb and SCr testing, this approach could be more widely adopted in kidney care. OBJECTIVE: We assessed time trends and facility-level variation in the performance of outpatient dual testing in the integrated Veterans Health Administration (VHA) system. DESIGN, SUBJECTS AND MAIN MEASURES: This retrospective cohort study included patients with any inpatient or outpatient visit to the VHA system during the period 2009-2018. Dual testing was defined as UAlb and SCr testing in the outpatient setting within a calendar year. We assessed time trends in dual testing by demographics, comorbidities, high-risk (eg, diabetes) specialty care and facilities. A generalised linear mixed-effects model was applied to explore individual and facility-level predictors of receiving dual testing. KEY RESULTS: We analysed data from approximately 6.9 million veterans per year. Dual testing increased, on average, from 17.4% to 21.2%, but varied substantially among VHA centres (0.3%-43.7% in 2018). Dual testing was strongly associated with diabetes (OR 10.4, 95% CI 10.3 to 10.5, p<0.0001) and not associated with VHA centre complexity level. However, among patients with high-risk conditions including diabetes, <50% received dual testing in any given year. As compared with white veterans, black veterans were less likely to be tested after adjusting for other individual and facility characteristics (OR 0.93, 95% CI 0.92 to 0.93, p<0.0001). CONCLUSIONS: Dual testing for CKD in high-risk specialties is increasing but remains low. This appears primarily due to low rates of testing for albuminuria. Promoting dual testing in high-risk patients will help to improve disease management and patient outcomes.

Muscle Mass and Serum Creatinine Concentration by Race and Ethnicity among Hemodialysis Patients.

SIGNIFICANCE STATEMENT: Serum creatinine is a product of skeletal muscle metabolism. Differences in serum creatinine concentration between Black and non-Black individuals have been attributed to differences in muscle mass but have not been thoroughly examined. Furthermore, other race and ethnic groups have not been considered. If differences in body composition explain differences in serum concentration by race or ethnicity, then estimates of body composition could be used in eGFR equations rather than race. Adjustment for intracellular water (ICW) as a proxy of muscle mass among patients with kidney failure in whom creatinine clearance should minimally influence serum concentration does not explain race- and ethnicity-dependent differences. BACKGROUND: Differences in serum creatinine concentration among groups defined by race and ethnicity have been ascribed to differences in muscle mass. We examined differences in serum creatinine by race and ethnicity in a cohort of patients receiving hemodialysis in whom creatinine elimination by the kidney should have little or no effect on serum creatinine concentration and considered whether these differences persisted after adjustment for proxies of muscle mass. METHODS: We analyzed data from 501 participants in the A Cohort Study to Investigate the Value of Exercise in ESKD/Analyses Designed to Investigate the Paradox of Obesity and Survival in ESKD study who had been receiving hemodialysis for >1 year. We examined the independent associations among race and ethnicity (Black, Asian, non-Hispanic White, and Hispanic), serum creatinine, and ICW (L/m 2 ), a proxy for muscle mass, derived by whole-body multifrequency bioimpedance spectroscopy, using multivariable linear regression with adjustment for several demographic, clinical, and laboratory characteristics. We examined the association of race and ethnicity with serum creatinine concentration with and without adjustment for ICW. RESULTS: Black, Asian, and Hispanic patients had higher serum creatinine concentrations (+1.68 mg/dl [95% confidence interval (CI), 1.09 to 2.27], +1.61 mg/dl [95% CI, 0.90 to 2.32], and +0.83 [95% CI, 0.08 to 1.57], respectively) than non-Hispanic White patients. Overall, ICW was associated with serum creatinine concentration (0.26 mg/dl per L/m 2 ICW; 95% CI, 0.006 to 0.51) but was not statistically significantly different by race and ethnicity. Black, Asian, and Hispanic race and ethnicity remained significantly associated with serum creatinine concentration after adjustment for ICW. CONCLUSION: Among patients receiving dialysis, serum creatinine was higher in Black, Asian, and Hispanic patients than in non-Hispanic White patients. Differences in ICW did not explain the differences in serum creatinine concentration across race groups.

Engineering Equity Into the Promise of Xenotransplantation.

Two of the greatest challenges facing kidney transplantation are the lack of donated organs and inequities in who receives a transplant. Xenotransplantation holds promise as a treatment approach that could solve the supply problem. Major advances in gene-editing procedures have enabled several companies to raise genetically engineered pigs for organ donation. These porcine organs lack antigens and have other modifications that should reduce the probability of immunological rejection when transplanted into humans. The US Food and Drug Administration and transplantation leaders are starting to chart a path to test xenotransplants in clinical trials and later integrate them into routine clinical care. Here we provide a framework that industry, regulatory authorities, payers, transplantation professionals, and patient groups can implement to promote equity during every stage in this process. We also call for immediate action. Companies developing xenotransplant technology should assemble patient advocacy boards to bring the concerns of individuals with end-stage kidney disease to the forefront. For trials, xenotransplantation companies should partner with transplant programs with substantial patient populations of racial and ethnic minority groups and that have reciprocal relationships with those communities. Those companies and transplant programs should reach out now to those communities to inform them about xenotransplantation and try to address their concerns. These actions have the potential to make these communities full partners in the promise of xenotransplantation.

Hospital Equity Rating Metrics-Promise, Pitfalls, and Perils.

This Viewpoint addresses several considerations regarding equity metrics across hospital regulatory and accrediting organizations and suggestions for improvement.

Utility of the Kidney Failure Risk Equation and Estimated GFR for Estimating Time to Kidney Failure in Advanced CKD.

RATIONALE & OBJECTIVE: The Kidney Failure Risk Equation (KFRE) predicts the 2-year risk of kidney failure for patients with chronic kidney disease (CKD). Translating KFRE-predicted risk or estimated glomerular filtration rate (eGFR) into time to kidney failure could inform decision making for patients approaching kidney failure. STUDY DESIGN: Retrospective cohort. SETTING & PARTICIPANTS: CKD Outcomes and Practice Patterns Study (CKDOPPS) cohort of patients with an eGFR<60mL/min/1.73m2 from 34 US nephrology practices (2013-2021). EXPOSURE: 2-year KFRE risk or eGFR. OUTCOME: Kidney failure defined as initiation of dialysis or kidney transplantation. ANALYTICAL APPROACH: Accelerated failure time (Weibull) models used to estimate the median, 25th, and 75th percentile times to kidney failure starting from KFRE values of 20%, 40%, and 50%, and from eGFR values of 20, 15, and 10mL/min/1.73m2. We examined variability in time to kidney failure by age, sex, race, diabetes status, albuminuria, and blood pressure. RESULTS: Overall, 1,641 participants were included (mean age 69±13 years; median eGFR of 28mL/min/1.73m2 [IQR 20-37mL/min/1.73 m2]). Over a median follow-up period of 19 months (IQR, 12-30 months), 268 participants developed kidney failure, and 180 died before reaching kidney failure. The median estimated time to kidney failure was widely variable across patient characteristics from an eGFR of 20mL/min/1.73m2 and was shorter for younger age, male sex, Black (versus non-Black), diabetes (vs no diabetes), higher albuminuria, and higher blood pressure. Estimated times to kidney failure were comparably less variable across these characteristics for KFRE thresholds and eGFR of 15 or 10mL/min/1.73m2. LIMITATIONS: Inability to account for competing risks when estimating time to kidney failure. CONCLUSIONS: Among those with eGFR<15mL/min/1.73m2 or KFRE risk>40%), both KFRE risk and eGFR showed similar relationships with time to kidney failure. Our results demonstrate that estimating time to kidney failure in advanced CKD can inform clinical decisions and patient counseling on prognosis, regardless of whether estimates are based on eGFR or the KFRE. PLAIN-LANGUAGE SUMMARY: Clinicians often talk to patients with advanced chronic kidney disease about the level of kidney function expressed as the estimated glomerular filtration rate (eGFR) and about the risk of developing kidney failure, which can be estimated using the Kidney Failure Risk Equation (KFRE). In a cohort of patients with advanced chronic kidney disease, we examined how eGFR and KFRE risk predictions corresponded to the time patients had until reaching kidney failure. Among those with eGFR<15mL/min/1.73m2 or KFRE risk > 40%), both KFRE risk and eGFR showed similar relationships with time to kidney failure. Estimating time to kidney failure in advanced CKD using either eGFR or KFRE can inform clinical decisions and patient counseling on prognosis.

Care of the Patient With Abnormal Kidney Test Results.

Blood and urine tests are commonly performed by clinicians in both ambulatory and hospital settings that detect chronic and acute kidney disease. Thresholds for these tests have been established that signal the presence and severity of kidney injury or dysfunction. In the appropriate clinical context of a patient's history and physical examination, an abnormal test result should trigger specific actions for clinicians, including reviewing patient medication use, follow-up testing, prescribing lifestyle modifications, and specialist referral. Tests for kidney disease can also be used to determine the future risk for kidney failure as well as cardiovascular death.

National Projections for Clinical Implications of Race-Free Creatinine-Based GFR Estimating Equations.

BACKGROUND: The National Kidney Foundation and American Society of Nephrology Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease recently recommended a new race-free creatinine-based equation for eGFR. The effect on recommended clinical care across race and ethnicity groups is unknown. METHODS: We analyzed nationally representative cross-sectional questionnaires and medical examinations from 44,360 participants collected between 2001 and 2018 by the National Health and Nutrition Examination Survey. We quantified the number and proportion of Black, White, Hispanic, and Asian/Other adults with guideline-recommended changes in care. RESULTS: The new equation, if applied nationally, could assign new CKD diagnoses to 434,000 (95% confidence interval [CI], 350,000 to 517,000) Black adults, reclassify 584,000 (95% CI, 508,000 to 667,000) to more advanced stages of CKD, restrict kidney donation eligibility for 246,000 (95% CI, 189,000 to 303,000), expand nephrologist referrals for 41,800 (95% CI, 19,800 to 63,800), and reduce medication dosing for 222,000 (95% CI, 169,000 to 275,000). Among non-Black adults, these changes may undo CKD diagnoses for 5.51 million (95% CI, 4.86 million to 6.16 million), reclassify 4.59 million (95% CI, 4.28 million to 4.92 million) to less advanced stages of CKD, expand kidney donation eligibility for 3.96 million (95% CI, 3.46 million to 4.46 million), reverse nephrologist referral for 75,800 (95% CI, 35,400 to 116,000), and reverse medication dose reductions for 1.47 million (95% CI, 1.22 million to 1.73 million). The racial and ethnic mix of the populations used to develop eGFR equations has a substantial effect on potential care changes. CONCLUSION: The newly recommended 2021 CKD-EPI creatinine-based eGFR equation may result in substantial changes to recommended care for US patients of all racial and ethnic groups.