Representation of Real-World Adults With Chronic Kidney Disease in Clinical Trials Supporting Blood Pressure Treatment Targets.

BACKGROUND: Little is known about how well trial participants with chronic kidney disease (CKD) represent real-world adults with CKD. We assessed the population representativeness of clinical trials supporting the 2021 Kidney Disease: Improving Global Outcomes blood pressure (BP) guidelines in real-world adults with CKD. METHODS AND RESULTS: Using a cross-sectional analysis, we identified patients with CKD who met the guideline definition of hypertension based on use of antihypertensive medications or sustained systolic BP ≥120 mm Hg in 2019 in the Veterans Affairs and Kaiser Permanente of Southern California. We applied the eligibility criteria from 3 BP target trials, SPRINT (Systolic Pressure Intervention Trial), ACCORD (Action to Control Cardiovascular Risk in Diabetes), and AASK (African American Study of Kidney Disease), to estimate the proportion of adults with a systolic BP above the guideline-recommended target and the proportion who met eligibility criteria for ≥1 trial. We identified 503 480 adults in the Veterans Affairs and 73 412 adults in Kaiser Permanente of Southern California with CKD and hypertension in 2019. We estimated 79.7% in the Veterans Affairs and 87.3% in the Kaiser Permanente of Southern California populations had a systolic BP ≥120 mm Hg; only 23.8% [23.7%-24.0%] in the Veterans Affairs and 20.8% [20.5%-21.1%] in Kaiser Permanente of Southern California were trial-eligible. Among trial-ineligible patients, >50% met >1 exclusion criteria. CONCLUSIONS: Major BP target trials were representative of fewer than 1 in 4 real-world adults with CKD and hypertension. A large proportion of adults who are at risk for cardiovascular morbidity from hypertension and susceptible to adverse treatment effects lack relevant treatment information.

Using Relative Survival to Estimate the Burden of Kidney Failure.

RATIONALE & OBJECTIVE: Estimates of mortality from kidney failure are misleading because the mortality from kidney failure is inseparable from the mortality attributed to comorbid conditions. We sought to develop an alternative method to reduce the bias in estimating mortality due to kidney failure using life table methods. STUDY DESIGN: Longitudinal cohort study. SETTING & PARTICIPANTS: Using data from the US Renal Data System and the Medicare 5% sample, we identified an incident cohort of patients, age 66+, who first had kidney failure in 2009 and a similar general population cohort without kidney failure. EXPOSURE: Kidney failure. OUTCOME: Death. ANALYTICAL APPROACH: We created comorbidity, age, sex, race, and year-specific life tables to estimate relative survival of patients with incident kidney failure and to attain an estimate of excess kidney failure-related deaths. Estimates were compared with those based on standard life tables (not adjusted for comorbidity). RESULTS: The analysis included 31,944 adults with kidney failure with a mean age of 77±7 years. The 5-year relative survival was 31% using standard life tables (adjusted for age, sex, race, and year) versus 36% using life tables also adjusted for comorbidities. Compared with other chronic diseases, patients with kidney failure have among the lowest relative survival. Patients with incident kidney failure ages 66-70 and 76-80 have a survival comparable to adults without kidney failure roughly 86-90 and 91-95 years old, respectively. LIMITATIONS: Relative survival estimates can be improved by narrowing the specificity of the covariates collected (eg, disease severity and ethnicity). CONCLUSIONS: Estimates of survival relative to a matched general population partition the mortality due to kidney failure from other causes of death. Results highlight the immense burden of kidney failure on mortality and the importance of disease prevention efforts among older adults. PLAIN-LANGUAGE SUMMARY: Estimates of death due to kidney failure can be misleading because death information from kidney failure is intertwined with death due to aging and other chronic diseases. Life tables are an old method, commonly used by actuaries and demographers to describe the life expectancy of a population. We developed life tables specific to a patient's age, sex, year, race, and comorbidity. Survival is derived from the life tables as the percentage of patients who are still alive in a specified period. By comparing survival of patients with kidney failure to the survival of people from the general population, we estimate that patients with kidney failure have one-third the chance of survival in 5 years compared with people with similar demographics and comorbidity but without kidney failure. The importance of this measure is that it provides a quantifiable estimate of the immense mortality burden of kidney failure.

Treatment and Control of Hypertension Among Adults With Chronic Kidney Disease, 2011 to 2019.

BACKGROUND: Hypertension frequently accompanies chronic kidney disease (CKD) as etiology and sequela. We examined contemporary trends in hypertension treatment and control in a national sample of adults with CKD. METHODS: We evaluated 5% cross-sectional samples of adults with CKD between 2011 and 2019 in the Veterans Health Administration. We defined CKD as a sustained estimated glomerular filtration rate value <60 mL/min per 1.73 m2 or a urine albumin-to-creatinine ratio ≥30 mg/g. The main outcomes were blood pressure (BP) control, defined as a systolic BP <140 mm Hg and a diastolic BP <90 mm Hg based on the mean of monthly BP measurements, and prescriptions for antihypertensive medications. RESULTS: The annual samples ranged between n=22 110 and n=33 039 individuals, with a mean age of 72 years, 96% of whom were men. Between 2011 and 2014, the age-adjusted proportion of adults with controlled BP declined from 78.0% to 72.2% (P value for linear trend, <0.001), reached a nadir of 71.0% in 2015, and then increased to 72.9% by 2019 (P value for linear trend, <0.001). Among adults with BP above goal, the age-adjusted proportion who did not receive antihypertensive treatment increased throughout the decade from 18.8% to 21.6%, and the age-adjusted proportion who received ≥3 antihypertensive medications decreased from 41.8% to 36.3%. Prescriptions for first-line antihypertensive agents also decreased. CONCLUSIONS: Among adults with CKD treated in the Veterans Health Administration, the proportion with controlled BP declined between 2011 and 2015 followed by a modest increase, coinciding with fewer prescriptions for antihypertensive medications.

Estimated Effect of Parathyroidectomy on Long-Term Kidney Function in Adults With Primary Hyperparathyroidism.

BACKGROUND: Multidisciplinary guidelines recommend parathyroidectomy to slow the progression of chronic kidney disease in patients with primary hyperparathyroidism (PHPT) and an estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2. Limited data address the effect of parathyroidectomy on long-term kidney function. OBJECTIVE: To compare the incidence of a sustained decline in eGFR of at least 50% among patients with PHPT treated with parathyroidectomy versus nonoperative management. DESIGN: Target trial emulation was done using observational data from adults with PHPT, using an extended Cox model with time-varying inverse probability weighting. SETTING: Veterans Health Administration. PATIENTS: Patients with a new biochemical diagnosis of PHPT in 2000 to 2019. MEASUREMENTS: Sustained decline of at least 50% from pretreatment eGFR. RESULTS: Among 43 697 patients with PHPT (mean age, 66.8 years), 2928 (6.7%) had a decline of at least 50% in eGFR over a median follow-up of 4.9 years. The weighted cumulative incidence of eGFR decline was 5.1% at 5 years and 10.8% at 10 years in patients managed with parathyroidectomy, compared with 5.1% and 12.0%, respectively, in those managed nonoperatively. The adjusted hazard of eGFR decline did not differ between parathyroidectomy and nonoperative management (hazard ratio [HR], 0.98 [95% CI, 0.82 to 1.16]). Subgroup analyses found no heterogeneity of treatment effect based on pretreatment kidney function. Parathyroidectomy was associated with a reduced hazard of the primary outcome among patients younger than 60 years (HR, 0.75 [CI, 0.59 to 0.93]) that was not evident among those aged 60 years or older (HR, 1.08 [CI, 0.87 to 1.34]). LIMITATION: Analyses were done in a predominantly male cohort using observational data. CONCLUSION: Parathyroidectomy had no effect on long-term kidney function in older adults with PHPT. Potential benefits related to kidney function should not be the primary consideration for PHPT treatment decisions. PRIMARY FUNDING SOURCE: National Institute on Aging.

Value Placed on Comfort vs Life Prolongation Among Patients Treated With Maintenance Dialysis.

Importance: Patients receiving maintenance dialysis experience intensive patterns of end-of-life care that might not be consistent with their values. Objective: To evaluate the association of patients' health care values with engagement in advance care planning and end-of-life care. Design, Setting, and Participants: Survey study of patients who received maintenance dialysis between 2015 and 2018 at dialysis centers in the greater metropolitan areas of Seattle, Washington, and Nashville, Tennessee, with longitudinal follow-up of decedents. Logistic regression models were used to estimate probabilities. Data analysis was conducted between May and October 2022. Exposures: A survey question about the value that the participant would place on longevity-focused vs comfort-focused care if they were to become seriously ill. Main Outcomes and Measures: Self-reported engagement in advance care planning and care received near the end of life through 2020 using linked kidney registry data and Medicare claims. Results: Of 933 patients (mean [SD] age, 62.6 [14.0] years; 525 male patients [56.3%]; 254 [27.2%] identified as Black) who responded to the question about values and could be linked to registry data (65.2% response rate [933 of 1431 eligible patients]), 452 (48.4%) indicated that they would value comfort-focused care, 179 (19.2%) that they would value longevity-focused care, and 302 (32.4%) that they were unsure about the intensity of care they would value. Many had not completed an advance directive (estimated probability, 47.5% [95% CI, 42.9%-52.1%] of those who would value comfort-focused care vs 28.1% [95% CI, 24.0%-32.3%] of those who would value longevity-focused care or were unsure; P < .001), had not discussed hospice (estimated probability, 28.6% [95% CI, 24.6%-32.9%] comfort focused vs 18.2% [95% CI, 14.7%-21.7%] longevity focused or unsure; P < .001), or had not discussed stopping dialysis (estimated probability, 33.3% [95% CI, 29.0%-37.7%] comfort focused vs 21.9% [95% CI, 18.2%-25.8%] longevity focused or unsure; P < .001). Most respondents wanted to receive cardiopulmonary resuscitation (estimated probability, 78.0% [95% CI, 74.2%-81.7%] comfort focused vs 93.9% [95% CI, 91.4%-96.1%] longevity focused or unsure; P < .001) and mechanical ventilation (estimated probability, 52.0% [95% CI, 47.4%-56.6%] comfort focused vs 77.9% [95% CI, 74.0%-81.7%] longevity focused or unsure; P < .001). Among decedents, the percentages of participants who received an intensive procedure during the final month of life (estimated probability, 23.5% [95% CI, 16.5%-31.0%] comfort focused vs 26.1% [95% CI, 18.0%-34.5%] longevity focused or unsure; P = .64), discontinued dialysis (estimated probability, 38.3% [95% CI, 32.0%-44.8%] comfort focused vs 30.2% [95% CI, 23.0%-37.8%] longevity focused or unsure; P = .09), and enrolled in hospice (estimated probability, 32.2% [95% CI, 25.7%-38.7%] comfort focused vs 23.3% [95% CI, 16.4%-30.5%] longevity focused or unsure; P = .07) were not statistically different. Conclusions and Relevance: This survey study found that there appeared to be a disconnect between patients' expressed values, which were largely comfort focused, and their engagement in advance care planning and end-of-life care, which reflected a focus on longevity. These findings suggest important opportunities to improve the quality of care for patients receiving dialysis.

Prevalence of Apparent Treatment-Resistant Hypertension in Chronic Kidney Disease in Two Large US Health Care Systems.

BACKGROUND AND OBJECTIVES: More intensive BP goals have been recommended for patients with CKD. We estimated the prevalence of apparent treatment-resistant hypertension among patients with CKD according to the 2017 American College of Cardiology/American Heart Association (ACC/AHA; BP goal <130/80 mm Hg) and 2021 Kidney Disease Improving Global Outcomes (KDIGO; systolic BP <120 mm Hg) guidelines in two US health care systems. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We included adults with CKD (an eGFR <60 ml/min per 1.73 m2) and treated hypertension from Kaiser Permanente Southern California and the Veterans Health Administration. Using electronic health records, we identified apparent treatment-resistant hypertension on the basis of (1) BP above the goal while prescribed three or more classes of antihypertensive medications or (2) prescribed four or more classes of antihypertensive medications regardless of BP. In a sensitivity analysis, we required diuretic use to be classified as apparent treatment-resistant hypertension. We estimated the prevalence of apparent treatment-resistant hypertension per clinical guideline and by CKD stage. RESULTS: Among 44,543 Kaiser Permanente Southern California and 241,465 Veterans Health Administration patients with CKD and treated hypertension, the prevalence rates of apparent treatment-resistant hypertension were 39% (Kaiser Permanente Southern California) and 35% (Veterans Health Administration) per the 2017 ACC/AHA guideline and 48% (Kaiser Permanente Southern California) and 55% (Veterans Health Administration) per the 2021 KDIGO guideline. By requiring a diuretic as a criterion for apparent treatment-resistant hypertension, the prevalence rates of apparent treatment-resistant hypertension were lowered to 31% (Kaiser Permanente Southern California) and 23% (Veterans Health Administration) per the 2017 ACC/AHA guideline. The prevalence rates of apparent treatment-resistant hypertension were progressively higher at more advanced stages of CKD (34%/33%, 42%/36%, 52%/41%, and 60%/37% for Kaiser Permanente Southern California/Veterans Health Administration eGFR 45-59, 30-44, 15-29, and <15 ml/min per 1.73 m2, respectively) per the 2017 ACC/AHA guideline. CONCLUSIONS: Depending on the CKD stage, up to a half of patients with CKD met apparent treatment-resistant hypertension criteria.

Implementation and Effectiveness of a Learning Collaborative to Improve Palliative Care for Seriously Ill Hemodialysis Patients.

BACKGROUND AND OBJECTIVES: Limited implementation of palliative care practices in hemodialysis may contribute to end-of-life care that is intensive and not patient centered. We determined whether a learning collaborative for hemodialysis center providers improved delivery of palliative care best practices. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Ten US hemodialysis centers participated in a pre-post study targeting seriously ill patients between April 2019 and September 2020. Three practices were prioritized: screening for serious illness, goals of care discussions, and use of a palliative dialysis care pathway. The collaborative educational bundle consisted of learning sessions, communication skills training, and implementation support. The primary outcome was change in the probability of complete advance care planning documentation among seriously ill patients. Health care utilization was a secondary outcome, and implementation outcomes of acceptability, adoption, feasibility, and penetration were assessed using mixed methods. RESULTS: One center dropped out due to the coronavirus disease 2019 pandemic. Among the remaining nine centers, 20% (273 of 1395) of patients were identified as seriously ill preimplementation, and 16% (203 of 1254) were identified as seriously ill postimplementation. From the preimplementation to postimplementation period, the adjusted probability of complete advance care planning documentation among seriously ill patients increased by 34.5 percentage points (95% confidence interval, 4.4 to 68.5). There was no difference in mortality or in utilization of palliative hemodialysis, hospice referral, or hemodialysis discontinuation. Screening for serious illness was widely adopted, and goals of care discussions were adopted with incomplete integration. There was limited adoption of a palliative dialysis care pathway. CONCLUSIONS: A learning collaborative for hemodialysis centers spanning the coronavirus disease 2019 pandemic was associated with adoption of serious illness screening and goals of care discussions as well as improved documentation of advance care planning for seriously ill patients. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Pathways Project: Kidney Supportive Care, NCT04125537.

Kidney Stone Events Following Parathyroidectomy vs Nonoperative Management for Primary Hyperparathyroidism.

CONTEXT: Primary hyperparathyroidism (PHPT) is associated with an increased risk of kidney stones. Few studies account for PHPT severity or stone risk when comparing stone events after parathyroidectomy vs nonoperative management. OBJECTIVE: Compare the incidence of kidney stone events in PHPT patients treated with parathyroidectomy vs nonoperative management. DESIGN: Longitudinal cohort study with propensity score inverse probability weighting and multivariable Cox proportional hazards regression. SETTING: Veterans Health Administration integrated health care system. PATIENTS: A total of 44 978 patients with > 2 years follow-up after PHPT diagnosis (2000-2018); 5244 patients (11.7%) were treated with parathyroidectomy. MAIN OUTCOMES MEASURE: Clinically significant kidney stone event. RESULTS: The cohort had a mean age of 66.0 years, was 87.8% male, and 66.4% White. Patients treated with parathyroidectomy had higher mean serum calcium (11.2 vs 10.8mg/dL) and were more likely to have a history of kidney stone events. Among patients with baseline history of kidney stones, the unadjusted incidence of ≥ 1 kidney stone event was 30.5% in patients managed with parathyroidectomy (mean follow-up, 5.6 years) compared with 18.0% in those managed nonoperatively (mean follow-up, 5.0 years). Patients treated with parathyroidectomy had a higher adjusted hazard of recurrent kidney stone events (hazard ratio [HR], 1.98; 95% CI, 1.56-2.51); however, this association declined over time (parathyroidectomy × time: HR, 0.80; 95% CI, 0.73-0.87). CONCLUSION: In this predominantly male cohort with PHPT, patients treated with parathyroidectomy continued to be at higher risk of kidney stone events in the immediate years after treatment than patients managed nonoperatively, although the adjusted risk of stone events declined with time, suggesting a benefit to surgical treatment.

The Relationship of Kidney Tubule Biomarkers with Brain Imaging in CKD Patients in SPRINT.

Urine biomarker concentrations reflecting kidney tubule injury and dysfunction were not associated with brain MRI measures.Higher eGFR was associated with lower total brain cerebral blood flow.This is the first evaluation of the relationship of kidney tubule biomarkers with brain imaging by MRI in patients with CKD.

Kidney Disease, Hypertension Treatment, and Cerebral Perfusion and Structure.

RATIONALE & OBJECTIVE: The safety of intensive blood pressure (BP) targets is controversial for persons with chronic kidney disease (CKD). We studied the effects of hypertension treatment on cerebral perfusion and structure in individuals with and without CKD. STUDY DESIGN: Neuroimaging substudy of a randomized trial. SETTING & PARTICIPANTS: A subset of participants in the Systolic Blood Pressure Intervention Trial (SPRINT) who underwent brain magnetic resonance imaging studies. Presence of baseline CKD was assessed by estimated glomerular filtration rate (eGFR) and urinary albumin-creatinine ratio (UACR). INTERVENTION: Participants were randomly assigned to intensive (systolic BP <120 mm Hg) versus standard (systolic BP <140 mm Hg) BP lowering. OUTCOMES: The magnetic resonance imaging outcome measures were the 4-year change in global cerebral blood flow (CBF), white matter lesion (WML) volume, and total brain volume (TBV). RESULTS: A total of 716 randomized participants with a mean age of 68 years were enrolled; follow-up imaging occurred after a median 3.9 years. Among participants with eGFR <60 mL/min/1.73 m2 (n = 234), the effects of intensive versus standard BP treatment on change in global CBF, WMLs, and TBV were 3.38 (95% CI, 0.32 to 6.44) mL/100 g/min, -0.06 (95% CI, -0.16 to 0.04) cm3 (inverse hyperbolic sine-transformed), and -3.8 (95% CI, -8.3 to 0.7) cm3, respectively. Among participants with UACR >30 mg/g (n = 151), the effects of intensive versus standard BP treatment on change in global CBF, WMLs, and TBV were 1.91 (95% CI, -3.01 to 6.82) mL/100 g/min, 0.003 (95% CI, -0.13 to 0.13) cm3 (inverse hyperbolic sine-transformed), and -7.0 (95% CI, -13.3 to -0.3) cm3, respectively. The overall treatment effects on CBF and TBV were not modified by baseline eGFR or UACR; however, the effect on WMLs was attenuated in participants with albuminuria (P = 0.04 for interaction). LIMITATIONS: Measurement variability due to multisite design. CONCLUSIONS: Among adults with hypertension who have primarily early kidney disease, intensive versus standard BP treatment did not appear to have a detrimental effect on brain perfusion or structure. The findings support the safety of intensive BP treatment targets on brain health in persons with early kidney disease. FUNDING: SPRINT was funded by the National Institutes of Health (including the National Heart, Lung, and Blood Institute; the National Institute of Diabetes and Digestive and Kidney Diseases; the National Institute on Aging; and the National Institute of Neurological Disorders and Stroke), and this substudy was funded by the National Institutes of Diabetes and Digestive and Kidney Diseases. TRIAL REGISTRATION: SPRINT was registered at ClinicalTrials.gov with study number NCT01206062.

Association Between Self-reported Importance of Religious or Spiritual Beliefs and End-of-Life Care Preferences Among People Receiving Dialysis.

Importance: Although people receiving maintenance dialysis have limited life expectancy and a high burden of comorbidity, relatively few studies have examined spirituality and religious beliefs among members of this population. Objective: To examine whether there is an association between the importance of religious or spiritual beliefs and care preferences and palliative care needs in people who receive dialysis. Design, Setting, and Participants: A cross-sectional survey study was conducted among adults who were undergoing maintenance dialysis at 31 facilities in Seattle, Washington, and Nashville, Tennessee, between April 22, 2015, and October 2, 2018. The survey included a series of questions assessing patients' knowledge, preferences, values, and expectations related to end-of-life care. Data were analyzed from February 12, 2020, to April 21, 2021. Exposures: The importance of religious or spiritual beliefs was ascertained by asking participants to respond to this statement: "My religious or spiritual beliefs are what really lie behind my whole approach to life." Response options were definitely true, tends to be true, tends not to be true, or definitely not true. Main Outcomes and Measurements: Outcome measures were based on self-reported engagement in advance care planning, resuscitation preferences, values regarding life prolongation, preferred place of death, decision-making preference, thoughts or discussion about hospice or stopping dialysis, prognostic expectations, and palliative care needs. Results: A total of 937 participants were included in the cohort, of whom the mean (SD) age was 62.8 (13.8) years and 524 (55.9%) were men. Overall, 435 (46.4%) participants rated the statement about religious or spiritual beliefs as definitely true, 230 (24.6%) rated it as tends to be true, 137 (14.6%) rated it as tends not to be true, and 135 (14.4%) rated it as definitely not true. Participants for whom these beliefs were more important were more likely to prefer cardiopulmonary resuscitation (estimated probability for definitely true: 69.8% [95% CI, 66.5%-73.2%]; tends to be true: 60.8% [95% CI, 53.4%-68.3%]; tends not to be true: 61.6% [95% CI, 53.6%-69.6%]; and definitely not true: 60.6% [95% CI, 52.5%-68.6%]; P for trend = .003) and mechanical ventilation (estimated probability for definitely true: 42.6% [95% CI, 38.1%-47.0%]; tends to be true: 33.5% [95% CI, 25.9%-41.2%]; tends not to be true: 35.1% [95% CI, 27.2%-42.9%]; and definitely not true: 27.9% [95% CI, 19.6%-36.1%]; P for trend = .002) and to prefer a shared role in decision-making (estimated probability for definitely true: 41.6% [95% CI, 37.7%-45.5%]; tends to be true: 35.4% [95% CI, 29.0%-41.8%]; tends not to be true: 36.0% [95% CI, 26.7%-45.2%]; and definitely not true: 23.8% [95% CI, 17.3%-30.3%]; P for trend = .001) and were less likely to have thought or spoken about stopping dialysis. These participants were no less likely to have engaged in advance care planning, to value relief of pain and discomfort, to prefer to die at home, to have ever thought or spoken about hospice, and to have unmet palliative care needs and had similar prognostic expectations. Conclusions and Relevance: The finding that religious or spiritual beliefs were important to most study participants suggests the value of an integrative approach that addresses these beliefs in caring for people who receive dialysis.

National Estimates of CKD Prevalence and Potential Impact of Estimating Glomerular Filtration Rate Without Race.

BACKGROUND: The implications of removing the adjustment for Black race in equations to eGFR on the prevalence of CKD and management strategies are incompletely understood. METHODS: We estimated changes in CKD prevalence and the potential effect on therapeutic drug prescriptions and prediction of kidney failure if race adjustment were removed from the CKD-EPI GFR estimating equation. We used cross-sectional and longitudinal data from adults aged ≥18 years in the National Health and Nutrition Examination Survey (NHANES) from 2015 to 2016, and the Veterans Affairs (VA) Health Care System in 2015. In the VA cohort, we assessed use of common medications that require dose adjustment on the basis of kidney function, and compared the prognostic accuracy of the Kidney Failure Risk Equation with versus without race adjustment of eGFR. RESULTS: The prevalence of CKD among Black adults increased from 5.2% to 10.6% in NHANES, and from 12.4% to 21.6% in the VA cohort after eliminating race adjustment. Among Black veterans, 41.0% of gabapentin users, 33.5% of ciprofloxacin users, 24.0% of metformin users, 6.9% of atenolol users, 6.6% of rosuvastatin users, and 5.8% of tramadol users were reclassified to a lower eGFR for which dose adjustment or discontinuation is recommended. Without race adjustment of eGFR, discrimination of the Kidney Failure Risk Equation among Black adults remained high and calibration was marginally improved overall, with better calibration at higher levels of predicted risk. CONCLUSIONS: Removal of race adjustment from CKD-EPI eGFR would double the estimated prevalence of CKD among Black adults in the United States. Such a change is likely to affect a sizeable number of drug-dosing decisions. It may also improve the accuracy of kidney failure risk prediction among higher-risk Black adults.

Atrial Fibrillation and Longitudinal Change in Cognitive Function in CKD.

BACKGROUND: Studies in the general population suggest that atrial fibrillation (AF) is an independent risk factor for decline in cognitive function, but this relationship has not been examined in adults with chronic kidney disease (CKD). We investigated the association between incident AF and changes in cognitive function over time in this population. METHODS AND RESULTS: We studied a subgroup of 3254 adults participating in the Chronic Renal Insufficiency Cohort Study. Incident AF was ascertained by 12-lead electrocardiogram (ECG) obtained at a study visit and/or identification of a hospitalization with AF during follow-up. Cognitive function was assessed biennially using the Modified Mini-Mental State Exam. Linear mixed effects regression was used to evaluate the association between incident AF and longitudinal change in cognitive function. Compared with individuals without incident AF (n = 3158), those with incident AF (n = 96) were older, had a higher prevalence of cardiovascular disease and hypertension, and lower estimated glomerular filtration rate. After median follow-up of 6.8 years, we observed no significant multivariable association between incident AF and change in cognitive function test score. CONCLUSION: In this cohort of adults with CKD, incident AF was not associated with a decline in cognitive function.

Association of Urine Biomarkers of Kidney Tubule Injury and Dysfunction With Frailty Index and Cognitive Function in Persons With CKD in SPRINT.

RATIONALE & OBJECTIVE: The associations of the glomerular markers of kidney disease, estimated glomerular filtration rate (eGFR) and albuminuria, with frailty and cognition are well established. However, the relationship of kidney tubule injury and dysfunction with frailty and cognition is unknown. STUDY DESIGN: Observational cross-sectional study. SETTING & PARTICIPANTS: 2,253 participants with eGFR<60mL/min/1.73m2 in the Systolic Blood Pressure Intervention Trial (SPRINT). EXPOSURE: Eight urine biomarkers: interleukin 18 (IL-18), kidney injury molecule 1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), chitinase-3-like protein 1 (YKL-40), monocyte chemoattractant protein 1 (MCP-1), α1-microglobulin (A1M), ß2-microglobulin (B2M), and uromodulin (Umod). OUTCOME: Frailty was measured using a previously validated frailty index (FI), categorized as fit (FI≤0.10), less fit (0.100.21). Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA). ANALYTICAL APPROACH: Associations between kidney tubule biomarkers with categorical FI were evaluated using multinomial logistic regression with the fit group as the reference. Cognitive function was evaluated using linear regression. Models were adjusted for demographic, behavioral, and clinical variables including eGFR and urine albumin. RESULTS: Three of the 8 urine biomarkers of tubule injury and dysfunction were independently associated with FI. Each 2-fold higher level of urine KIM-1, a marker of tubule injury, was associated with a 1.22 (95% CI, 1.01-1.49) greater odds of being in the frail group. MCP-1, a marker of tubulointerstitial fibrosis, was associated with a 1.30 (95% CI, 1.04-1.64) greater odds of being in the frail group, and A1M, a marker of tubule reabsorptive capacity, was associated with a 1.48 (95% CI, 1.11-1.96) greater odds of being in the frail group. These associations were independent of confounders including eGFR and urine albumin, and were stronger than those of urine albumin with FI (1.15 [95% CI, 0.99-1.34]). Higher urine B2M, another marker of tubule reabsorptive capacity, was associated with worse cognitive scores at baseline (ß: -0.09 [95% CI, -0.17 to-0.01]). Urine albumin was not associated with cognitive function. LIMITATIONS: Cross-sectional design, and FI may not be generalizable in other populations. CONCLUSIONS: Urine biomarkers of tubule injury, fibrosis, and proximal tubule reabsorptive capacity are variably associated with FI and worse cognition, independent of glomerular markers of kidney health. Future studies are needed to validate these results among other patient populations.

Facility-Level Variation in Dialysis Use and Mortality Among Older Veterans With Incident Kidney Failure.

Importance: Current guidelines lack consensus regarding the treatment of patients who may not benefit from dialysis; this lack of consensus may be associated with the substantial variation in dialysis use and outcomes across health care facilities. Objective: To assess the degree to which variation in dialysis use and mortality was associated with patient rather than facility characteristics and to distinguish which features identified the US Department of Veterans Affairs (VA) facilities with high rates of dialysis use. Design, Setting, and Participants: This cohort study analyzed data of veterans with stage 3 or 4 chronic kidney disease that progressed to kidney failure between January 1, 2011, and December 31, 2014. These patients received care from VA facilities across the US. Data sources included laboratory and administrative records from the VA, Medicare, and United States Renal Data System. Data analysis was conducted from August 1, 2019, to September 1, 2020. Exposures: The primary exposure was the VA facility in which patients received most of their care before the onset of incident kidney failure defined as the first occurrence of either a sustained estimated glomerular filtration rate of less than 15 mL/min/1.73 m2 or the initiation of maintenance dialysis. Main Outcomes and Measures: The primary outcomes were dialysis use and mortality within 2 years of incident kidney failure. Median rate ratio was used to quantify facility-level variation, and variance partition coefficient was used to quantify the sources of unexplained variation. Results: The cohort included 8695 older veterans with a mean (SD) age of 78.8 (7.5) years who were predominantly male (8573 [99%]) and White (6102 [70%]) individuals treated at 108 VA facilities. The observed frequency of dialysis use across facilities ranged from 25.0% to 81.4%, with a median (interquartile range [IQR]) rate of 51.7% (48.4%-60.0%). The observed frequency of mortality across facilities ranged from 27.2% to 60.0%, with a median (IQR) rate of 45.2% (41.2%-48.6%). The median rate ratio (adjusted for multiple patient and facility characteristics) was 1.40 for dialysis use and 1.08 for mortality. The unexplained variation in both outcomes mainly derived from patient characteristics rather than facility characteristics. No correlation was found between dialysis use and mortality at the facility level (correlation coefficient = 0.03). Conclusions and Relevance: This study found sizable variation in dialysis use for older adults that was poorly correlated with facility-level mortality rates and was not accounted for by differences in measured patient and facility characteristics. These findings suggest opportunities to improve the degree to which dialysis use practices align with the values, goals, and preferences of older adults with kidney failure.