Empagliflozin in Patients with Chronic Kidney Disease.

BACKGROUND: The effects of empagliflozin in patients with chronic kidney disease who are at risk for disease progression are not well understood. The EMPA-KIDNEY trial was designed to assess the effects of treatment with empagliflozin in a broad range of such patients. METHODS: We enrolled patients with chronic kidney disease who had an estimated glomerular filtration rate (eGFR) of at least 20 but less than 45 ml per minute per 1.73 m2 of body-surface area, or who had an eGFR of at least 45 but less than 90 ml per minute per 1.73 m2 with a urinary albumin-to-creatinine ratio (with albumin measured in milligrams and creatinine measured in grams) of at least 200. Patients were randomly assigned to receive empagliflozin (10 mg once daily) or matching placebo. The primary outcome was a composite of progression of kidney disease (defined as end-stage kidney disease, a sustained decrease in eGFR to <10 ml per minute per 1.73 m2, a sustained decrease in eGFR of ≥40% from baseline, or death from renal causes) or death from cardiovascular causes. RESULTS: A total of 6609 patients underwent randomization. During a median of 2.0 years of follow-up, progression of kidney disease or death from cardiovascular causes occurred in 432 of 3304 patients (13.1%) in the empagliflozin group and in 558 of 3305 patients (16.9%) in the placebo group (hazard ratio, 0.72; 95% confidence interval [CI], 0.64 to 0.82; P<0.001). Results were consistent among patients with or without diabetes and across subgroups defined according to eGFR ranges. The rate of hospitalization from any cause was lower in the empagliflozin group than in the placebo group (hazard ratio, 0.86; 95% CI, 0.78 to 0.95; P = 0.003), but there were no significant between-group differences with respect to the composite outcome of hospitalization for heart failure or death from cardiovascular causes (which occurred in 4.0% in the empagliflozin group and 4.6% in the placebo group) or death from any cause (in 4.5% and 5.1%, respectively). The rates of serious adverse events were similar in the two groups. CONCLUSIONS: Among a wide range of patients with chronic kidney disease who were at risk for disease progression, empagliflozin therapy led to a lower risk of progression of kidney disease or death from cardiovascular causes than placebo. (Funded by Boehringer Ingelheim and others; EMPA-KIDNEY ClinicalTrials.gov number, NCT03594110; EudraCT number, 2017-002971-24.).

Role of Age and Competing Risk of Death in the Racial Disparity of Kidney Failure Incidence after Onset of CKD.

SIGNIFICANCE STATEMENT: Black adults in the United States have 2-4 times higher incidence of kidney failure than White adults. Yet, the reasons underlying this disparity remain poorly understood. Among 547,188 US veterans with new-onset CKD, according to a new race-free GFR equation, Black veterans had a 2.5-fold higher cumulative incidence of kidney failure, compared with White veterans, in any follow-up period from CKD onset. This disparity resulted from a combination of higher hazards of progression to kidney failure and lower hazards of competing-risk death in Black veterans. Both, in turn, were largely explained by the younger age at CKD onset in Black veterans, underscoring an urgent need to prevent early onset and slow progression of CKD in younger Black adults. BACKGROUND: The Black adult population is well known to have higher incidence of kidney failure than their White counterpart in the United States, but the reasons underlying this disparity are unclear. We assessed the racial differences in kidney failure and death from onset of CKD on the basis of the race-free 2021 CKD Epidemiology Collaboration equation and examined the extent to which these differences could be explained by factors at the time of CKD onset. METHODS: We analyzed a national cohort consisting of 547,188 US veterans (103,821 non-Hispanic Black and 443,367 non-Hispanic White), aged 18-85 years, with new-onset CKD between 2005 and 2016 who were followed through 10 years or May 2018 for incident kidney failure with replacement therapy (KFRT) and pre-KFRT death. RESULTS: At CKD onset, Black veterans were, on average, 7.8 years younger than White veterans. In any time period from CKD onset, the cumulative incidence of KFRT was 2.5-fold higher for Black versus White veterans. Meanwhile, Black veterans had persistently >2-fold higher hazards of KFRT throughout follow-up (overall hazard ratio [95% confidence interval], 2.38 [2.31 to 2.45]) and conversely had 17%-48% decreased hazards of pre-KFRT death. These differences were reduced after accounting for the racial difference in age at CKD onset. CONCLUSIONS: The 2.5-fold higher cumulative incidence of kidney failure in Black adults resulted from a combination of higher hazards of progression to kidney failure and lower hazards of the competing risk of death, both of which can be largely explained by the younger age at CKD onset in Black compared with White adults.

Oral Sodium Bicarbonate and Bone Turnover in CKD: A Secondary Analysis of the BASE Pilot Trial.

SIGNIFICANCE STATEMENT: In CKD, metabolic acidosis is commonly treated with alkali in the hope that it will improve bone health. In a post hoc analysis of the Bicarbonate Administration to Stabilize eGFR Pilot Trial, we investigated whether sodium bicarbonate affects serum levels of bone turnover markers and other hormones related to bone health in individuals with CKD who have normal to slightly reduced total CO2 (20-28 mEq/L). Sodium bicarbonate increased serum levels of α-klotho but had no significant effect on other bone health markers, including intact fibroblast growth factor-23 (iFGF-23), intact parathyroid hormone (iPTH), and bone-specific alkaline phosphatase (B-SAP). Further study is needed to determine the effect of bicarbonate administration on clinical aspects of bone health. BACKGROUND: Treatment with alkali has been hypothesized to improve bone health in CKD by mitigating adverse effects of acid on bone mineral. We investigated the effect of treatment with sodium bicarbonate on bone turnover markers and other factors related to bone metabolism in CKD. METHODS: This is a post hoc analysis of the Bicarbonate Administration to Stabilize eGFR Pilot Trial in which 194 individuals with CKD and serum total CO2 20-28 mEq/L were randomly assigned to placebo or one of two doses of sodium bicarbonate (0.5 or 0.8 mEq/kg lean body weight per day) for 28 weeks. The following serum measurements were performed at baseline, week 12, and week 28: B-SAP, c-telopeptide, procollagen type I intact N-terminal propeptide, iPTH, iFGF-23, soluble klotho, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and tartrate-resistant acid phosphatase 5b. The difference (sodium bicarbonate versus placebo) in mean change of each bone biomarker from baseline was determined using linear mixed models. RESULTS: One hundred sixty-eight participants submitted samples for post hoc investigations. Mean eGFR was 37±10 ml/min per 1.73 m2 and mean total CO2 was 24±3 mEq/L at baseline. Sodium bicarbonate induced a dose-dependent increase in soluble klotho levels compared with placebo. There was no significant effect of treatment with either dose of sodium bicarbonate on any of the other bone biomarkers, including iFGF-23, iPTH, and B-SAP. Effects on bone biomarkers were similar in those with baseline serum total CO2 <24 mEq/L compared with those with total CO2 ≥24 mEq/L. CONCLUSIONS: In this pilot trial of individuals with CKD and total CO2 20-28 mEq/L, sodium bicarbonate treatment increased serum klotho levels but did not affect other bone health markers over 28 weeks. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: ClinicalTrials.gov, NCT02521181.

Final Report of a Trial of Intensive versus Standard Blood-Pressure Control.

BACKGROUND: In a previously reported randomized trial of standard and intensive systolic blood-pressure control, data on some outcome events had yet to be adjudicated and post-trial follow-up data had not yet been collected. METHODS: We randomly assigned 9361 participants who were at increased risk for cardiovascular disease but did not have diabetes or previous stroke to adhere to an intensive treatment target (systolic blood pressure, <120 mm Hg) or a standard treatment target (systolic blood pressure, <140 mm Hg). The primary outcome was a composite of myocardial infarction, other acute coronary syndromes, stroke, acute decompensated heart failure, or death from cardiovascular causes. Additional primary outcome events occurring through the end of the intervention period (August 20, 2015) were adjudicated after data lock for the primary analysis. We also analyzed post-trial observational follow-up data through July 29, 2016. RESULTS: At a median of 3.33 years of follow-up, the rate of the primary outcome and all-cause mortality during the trial were significantly lower in the intensive-treatment group than in the standard-treatment group (rate of the primary outcome, 1.77% per year vs. 2.40% per year; hazard ratio, 0.73; 95% confidence interval [CI], 0.63 to 0.86; all-cause mortality, 1.06% per year vs. 1.41% per year; hazard ratio, 0.75; 95% CI, 0.61 to 0.92). Serious adverse events of hypotension, electrolyte abnormalities, acute kidney injury or failure, and syncope were significantly more frequent in the intensive-treatment group. When trial and post-trial follow-up data were combined (3.88 years in total), similar patterns were found for treatment benefit and adverse events; however, rates of heart failure no longer differed between the groups. CONCLUSIONS: Among patients who were at increased cardiovascular risk, targeting a systolic blood pressure of less than 120 mm Hg resulted in lower rates of major adverse cardiovascular events and lower all-cause mortality than targeting a systolic blood pressure of less than 140 mm Hg, both during receipt of the randomly assigned therapy and after the trial. Rates of some adverse events were higher in the intensive-treatment group. (Funded by the National Institutes of Health; SPRINT ClinicalTrials.gov number, NCT01206062.).

Role of Anemia in Dementia Risk Among Veterans With Incident CKD.

RATIONALE & OBJECTIVE: Although some evidence exists of increased dementia risk from anemia, it is unclear whether this association persists among adults with CKD. Anemia may be a key marker for dementia among adults with CKD, so we evaluated whether anemia is associated with an increased risk of dementia among adults with CKD. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: The study included 620,095 veterans aged≥45 years with incident stage 3 CKD (estimated glomerular filtration rate [eGFR]<60mL/min/1.73m2) between January 2005 and December 2016 in the US Veterans Health Administration system and followed through December 31, 2018, for incident dementia, kidney failure, or death. EXPOSURE: Anemia was assessed based on the average of hemoglobin levels (g/L) during the 2 years before the date of incident CKD and categorized as normal, mild, or moderate/severe anemia (≥12.0, 11.0-11.9,<11.0g/dL, respectively, for women, and≥13.0, 11.0-12.9,<11.0g/dL for men). OUTCOME: Dementia and the composite outcome of kidney failure or death. ANALYTICAL APPROACH: Adjusted cause-specific hazard ratios were estimated for each outcome. RESULTS: At the time of incident CKD, the mean age of the participants was 72 years, 97% were male, and their mean eGFR was 51mL/min per 1.73m2. Over a median 4.1 years of follow-up, 92,306 veterans (15%) developed dementia before kidney failure or death. Compared with the veterans with CKD without anemia, the multivariable-adjusted models showed a 16% (95% CI, 14%-17%) significantly higher risk of dementia for those with mild anemia and a 27% (95% CI, 23%-31%) higher risk with moderate/severe anemia. Combined risk of kidney failure or death was higher at 39% (95% CI, 37%-40%) and 115% (95% CI, 112%-119%) for mild and moderate/severe anemia, respectively, compared with no anemia. LIMITATIONS: Residual confounding from the observational study design. Findings may not be generalizable to the broader US population. CONCLUSIONS: Anemia was significantly associated with an increased risk of dementia among veterans with incident CKD, underscoring the role of anemia as a predictor of dementia risk. PLAIN-LANGUAGE SUMMARY: Adults with chronic kidney disease (CKD) often have anemia. Prior studies among adults in the general population suggest anemia is a risk factor for dementia, though it is unclear whether this association persists among adults with CKD. In this large study of veterans in the United States, we studied the association between anemia and the risk of 2 important outcomes in this population: (1) dementia and (2) kidney failure or death. We found that anemia was associated with a greater risk of dementia as well as risk of kidney failure or death. The study findings therefore emphasize the role of anemia as a key predictor of dementia risk among adults with CKD.

Markers of Kidney Tubular Secretion and Risk of Adverse Events in SPRINT Participants with CKD.

BACKGROUND: Kidney tubular secretion is an essential mechanism for clearing many common antihypertensive drugs and other metabolites and toxins. It is unknown whether novel measures of tubular secretion are associated with adverse events (AEs) during hypertension treatment. METHODS: Among 2089 SPRINT (Systolic Blood Pressure Intervention Trial) participants with baseline eGFR <60 ml/min per 1.73 m2, we created a summary secretion score by averaging across the standardized spot urine-to-plasma ratios of ten novel endogenous tubular secretion measures, with lower urine-to-plasma ratios reflecting worse tubular secretion. Multivariable Cox proportional hazards models were used to evaluate associations between the secretion score and risk of a composite of prespecified serious AEs (hypotension, syncope, bradycardia, AKI, electrolyte abnormalities, and injurious falls). The follow-up protocol for SPRINT routinely assessed two laboratory monitoring AEs (hyperkalemia and hypokalemia). RESULTS: Overall, 30% of participants experienced at least one AE during a median follow-up of 3.0 years. In multivariable models adjusted for eGFR and albuminuria, lower (worse) secretion scores at baseline were associated with greater risk of the composite AE outcome (hazard ratio per 1-SD lower secretion score, 1.16; 95% confidence interval, 1.04 to 1.27). In analyses of the individual AEs, lower secretion score was associated with significantly greater risk of AKI, serious electrolyte abnormalities, and ambulatory hyperkalemia. Associations were similar across randomized treatment assignment groups. CONCLUSION: Among SPRINT participants with CKD, worse tubular secretion was associated with greater risk of AEs, independent of eGFR and albuminuria.

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.

Age-Related Association between Multimorbidity and Mortality in US Veterans with Incident Chronic Kidney Disease.

INTRODUCTION: Mortality is an important long-term indicator of the public health impact of chronic kidney disease (CKD). We investigated the role of individual comorbidities and multimorbidity on age-specific mortality risk among US veterans with new-onset CKD. METHODS: The cohort included 892,005 veterans aged ≥18 years with incident CKD stage 3 between January 2004 and April 2018 in the US Veterans Health Administration (VHA) system and followed until death, December 2018, or up to 10 years. Incident CKD was defined as the first-time estimated glomerular filtration rate (eGFR) was <60 mL/min/1.73 m2 for >3 months. Comorbidities were ascertained using inpatient and outpatient clinical records in the VHA system and Medicare claims. We estimated death rates for any cardiovascular disease (CVD, a composite of 6 CVD conditions) and 15 non-CVD comorbidities, and adjusted risks of death (hazard ratio [HR], 95% confidence interval [CI]) overall and by age group at CKD incidence. RESULTS: At CKD incidence, the mean age was 72 years, and 97% were male; the mean eGFR was 52 mL/min/1.73 m2, and 95% had ≥2 comorbidities (median, 4) in addition to CKD. During a median follow-up of 4.5 years, among the 16 comorbidities, CVD was associated with the highest relative risk of death in younger veterans (HR 1.96 [95% CI: 1.61-2.37] in ages 18-44 years and HR 1.66 [1.63-1.70] in ages 45-64 years). Dementia was associated with the highest relative risk of death among older veterans (HR 1.71 [1.68-1.74] in ages 65-84 years and HR 1.69 [1.65-1.73] in ages 85-100 years). The additive effect of multimorbidity on risk of death was stronger in younger than older veterans. Compared to having 1 or no comorbidity at CKD onset, the risk of death with ≥5 comorbidities was >7-fold higher among veterans aged 18-44 years and >2-fold higher among veterans aged 85-100 years. CONCLUSION: The large burden of comorbidities in US veterans with newly identified CKD places them at the risk of premature death. Compared with older veterans, younger veterans with multiple comorbidities, particularly with CVD, at CKD onset are at an even higher relative risk of death.

Kidney tubule health, mineral metabolism and adverse events in persons with CKD in SPRINT.

BACKGROUND: Measures of kidney tubule health are risk markers for acute kidney injury (AKI) in persons with chronic kidney disease (CKD) during hypertension treatment, but their associations with other adverse events (AEs) are unknown. METHODS: Among 2377 Systolic Blood Pressure Intervention Trial (SPRINT) participants with CKD, we measured at baseline eight urine biomarkers of kidney tubule health and two serum biomarkers of mineral metabolism pathways that act on the kidney tubules. Cox proportional hazards models were used to evaluate biomarker associations with risk of a composite of pre-specified serious AEs (hypotension, syncope, electrolyte abnormalities, AKI, bradycardia and injurious falls) and outpatient AEs (hyperkalemia and hypokalemia). RESULTS: At baseline, the mean age was 73 ± 9 years and mean estimated glomerular filtration rate (eGFR) was 46 ± 11 mL/min/1.73 m2. During a median follow-up of 3.8 years, 716 (30%) participants experienced the composite AE. Higher urine interleukin-18, kidney injury molecule-1, neutrophil gelatinase-associated lipocalin (NGAL) and monocyte chemoattractant protein-1 (MCP-1), lower urine uromodulin (UMOD) and higher serum fibroblast growth factor-23 were individually associated with higher risk of the composite AE outcome in multivariable-adjusted models including eGFR and albuminuria. When modeling biomarkers in combination, higher NGAL [hazard ratio (HR) = 1.08 per 2-fold higher biomarker level, 95% confidence interval (CI) 1.03-1.13], higher MCP-1 (HR = 1.11, 95% CI 1.03-1.19) and lower UMOD (HR = 0.91, 95% CI 0.85-0.97) were each associated with higher composite AE risk. Biomarker associations did not vary by intervention arm (P > 0.10 for all interactions). CONCLUSIONS: Among persons with CKD, several kidney tubule biomarkers are associated with higher risk of AEs during hypertension treatment, independent of eGFR and albuminuria.

Management of Blood Pressure in Patients With Chronic Kidney Disease Not Receiving Dialysis: Synopsis of the 2021 KDIGO Clinical Practice Guideline.

DESCRIPTION: The Kidney Disease: Improving Global Outcomes (KDIGO) 2021 clinical practice guideline for the management of blood pressure (BP) in patients with chronic kidney disease (CKD) not receiving dialysis is an update of the KDIGO 2012 guideline on the same topic and reflects new evidence on the risks and benefits of BP-lowering therapy among patients with CKD. It is intended to support shared decision making by health care professionals working with patients with CKD worldwide. This article is a synopsis of the full guideline. METHODS: The KDIGO leadership commissioned 2 co-chairs to convene an international Work Group of researchers and clinicians. After a Controversies Conference in September 2017, the Work Group defined the scope of the evidence review, which was undertaken by an evidence review team between October 2017 and April 2020. Evidence reviews were done according to the Cochrane Handbook. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach was used to guide the development of the recommendations and rate the strength and quality of the evidence. Practice points were included to provide guidance when evidence was insufficient to make a graded recommendation. The guideline was revised after public consultation between January and March 2020. RECOMMENDATIONS: The updated guideline comprises 11 recommendations and 20 practice points. This synopsis summarizes key recommendations pertinent to the diagnosis and management of high BP in adults with CKD, excluding those receiving kidney replacement therapy. In particular, the synopsis focuses on recommendations for standardized BP measurement and a target systolic BP of less than 120 mm Hg, because these recommendations differ from some other guidelines.

Plasma amyloid beta, neurofilament light chain, and total tau in the Systolic Blood Pressure Intervention Trial (SPRINT).

INTRODUCTION: Lowering blood pressure (BP) reduces the risk for cognitive impairment and the progression of cerebral white matter lesions. It is unclear whether hypertension control also influences plasma biomarkers related to Alzheimer's disease and non-disease-specific neurodegeneration. METHODS: We examined the effect of intensive (< 120 mm Hg) versus standard (< 140 mm Hg) BP control on longitudinal changes in plasma amyloid beta (Aß)40 and Aß42 , total tau, and neurofilament light chain (NfL) in a subgroup of participants from the Systolic Blood Pressure Intervention Trial (N = 517). RESULTS: Over 3.8 years, there were no significant between-group differences for Aß40, Aß42, Aß42 /Aß40, or total tau. Intensive treatment was associated with larger increases in NfL compared to standard treatment. Adjusting for kidney function, but not BP, attenuated the association between intensive treatment and NfL. DISCUSSION: Intensive BP treatment was associated with changes in NfL, which were correlated with changes in kidney function associated with intensive treatment. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01206062.

Executive summary of the KDIGO 2021 Clinical Practice Guideline for the Management of Blood Pressure in Chronic Kidney Disease.

The Kidney Disease: Improving Global Outcomes (KDIGO) 2021 Clinical Practice Guideline for the Management of Blood Pressure in Chronic Kidney Disease for patients not receiving dialysis represents an update to the KDIGO 2012 guideline on this topic. Development of this guideline update followed a rigorous process of evidence review and appraisal. Guideline recommendations are based on systematic reviews of relevant studies and appraisal of the quality of the evidence. The strength of recommendations is based on the "Grading of Recommendations Assessment, Development and Evaluation" (GRADE) approach. The scope includes topics covered in the original guideline, such as optimal blood pressure targets, lifestyle interventions, antihypertensive medications, and specific management in kidney transplant recipients and children. Some aspects of general and cardiovascular health, such as lipid and smoking management, are excluded. This guideline also introduces a chapter dedicated to proper blood pressure measurement since all large randomized trials targeting blood pressure with pivotal outcomes used standardized preparation and measurement protocols adhered to by patients and clinicians. Based on previous and new evidence, in particular the Systolic Blood Pressure Intervention Trial (SPRINT) results, we propose a systolic blood pressure target of less than 120 mm Hg using standardized office reading for most people with chronic kidney disease (CKD) not receiving dialysis, the exception being children and kidney transplant recipients. The goal of this guideline is to provide clinicians and patients a useful resource with actionable recommendations supplemented with practice points. The burden of the recommendations on patients and resources, public policy implications, and limitations of the evidence are taken into consideration. Lastly, knowledge gaps and recommendations for future research are provided.

Analyses of hemodialysis arteriovenous fistula geometric configuration and its associations with maturation and reintervention.

OBJECTIVE: An arteriovenous fistula (AVF) is the preferred vascular access for chronic hemodialysis; however, the rates of AVF maturation failure and reintervention remain high. We investigated the AVF geometric parameters and their associations with AVF physiologic maturation and reintervention in a prospective multicenter study. METHODS: From 2011 to 2016, patients undergoing vein end-to-artery side upper extremity AVF creation surgery were recruited. Contrast-free dark blood and phase-contrast magnetic resonance imaging (MRI) scans were performed using 3.0T scanners to obtain the AVF lumen geometry and flow rates, respectively, at postoperative day 1, week 6, and month 6. The arteriovenous anastomosis angle, nonplanarity, and tortuosity of the fistula were calculated according to the lumen centerlines. AVFs were considered physiologically matured if, using the week 6 MRI data, the flow rate was ≥500 mL/min and the minimum vein lumen diameter was ≥5 mm. The associations of these geometric parameters with AVF maturation and reintervention due to perianastomotic and mid-vein stenosis within 1 year were assessed. RESULTS: A total of 111 patients had a usable day 1 MRI scan, with most having upper arm AVFs (n = 73). Compared with the forearm AVFs, upper arm AVFs had greater anastomosis angles (P < .001), larger deviations from a plane (nonplanarity; P = .002), and more prominent tortuosity (P = .038) at day 1. These parameters significantly increased between day 1 and week 6 in upper arm AVFs. In contrast, significant changes in these parameters in forearm AVFs were not observed. The rate of maturation was 54% and 86% for forearm and upper arm AVFs, respectively. None of the geometric parameters at day 1 were associated with AVF maturation in either location. The rate of reintervention was 24% and 30% for forearm and upper arm AVFs, respectively, with a larger nonplanarity angle at day 1 associated with less reintervention (30° ± 15° vs 21° ± 10°; P = .034) in upper arm AVFs only. This relationship was unchanged after adjusting for age, sex, race, dialysis status, or diabetes. CONCLUSIONS: In our study, upper arm fistulas had a larger anastomosis angle, were more nonplanar, and had more tortuous veins than forearm fistulas. For upper arm fistulas, a larger nonplanarity angle is associated with a lower rate of reintervention within 1 year. Once confirmed, vascular surgeons could consider increasing the nonplanarity angle by incorporating a tension-free gentle curvature in the proximal segment of the mobilized vein to reduce reinterventions when creating an upper arm fistula.

Management of Cardiovascular Disease in Kidney Disease Study: Rationale and Design.

INTRODUCTION: Atherosclerosis, inflammation, and vascular stiffness are prominent interrelated risk factors contributing to the high incidence of cardiovascular disease (CVD) in patients with CKD. Conventional CVD management strategies in CKD largely target atherosclerotic CVD and have had a limited impact on the cardiovascular mortality in this population. Multiple in vivo and in vitro studies and epidemiological evidence from the rheumatologic cohorts have shown that low-dose hydroxychloroquine has beneficial effects on inflammation, endothelial function, insulin sensitivity, and metabolic syndrome. Our recent proof-of-concept animal study showed that hydroxychloroquine has marked protection against atherosclerosis and vascular stiffness. We hypothesize that hydroxychloroquine has the potential to provide significant cardiovascular benefits in patients with CKD. METHODS: The Management of Cardiovascular disease in Kidney disease study (NCT03636152) is a phase 2B, randomized, double-blind, placebo-controlled trial evaluating the effects of low-dose hydroxychloroquine therapy on the parameters of atherosclerosis, inflammation, and vascular stiffness in patients with CKD. The study plans to enroll 100 CKD patients estimated to be at high cardiovascular risk by a combination of low estimated glomerular filtration rate and albuminuria and treat them for 18 months with hydroxychloroquine or placebo in 1:1 allocation. RESULTS: The study will assess the change in the total carotid plaque volume as measured by serial noncontrast carotid MRI as the primary outcome and the serial changes in plasma inflammation markers, vascular stiffness, renal function, and the composition characteristics of the carotid plaque as secondary outcome measures. DISCUSSION/CONCLUSION: The results of this trial will provide the proof-of-applicability for hydroxychloroquine in the CVD in CKD. If positive, this trial should lead to phase-3 trials with clinical end points for this potentially transformative, novel, and inexpensive therapy for CVD in CKD.

Longitudinal Changes in Prorenin and Renin in the Chronic Renal Insufficiency Cohort.

INTRODUCTION: Prorenin, a precursor of renin, and renin play an important role in regulation of the renin-angiotensin system. More recently, receptor-bound prorenin has been shown to activate intracellular signaling pathways that mediate fibrosis, independent of angiotensin II. Prorenin and renin may thus be of physiologic significance in CKD, but their plasma concentrations have not been well characterized in CKD. METHODS: We evaluated distribution and longitudinal changes of prorenin and renin concentrations in the plasma samples collected at follow-up years 1, 2, 3, and 5 of the Chronic Renal Insufficiency Cohort (CRIC) study, an ongoing longitudinal observational study of 3,939 adults with CKD. Descriptive statistics and multivariable regression of log-transformed values were used to describe cross-sectional and longitudinal variation and associations with participant characteristics. RESULTS: A total of 3,361 CRIC participants had plasma available for analysis at year 1. The mean age (±standard deviation, SD) was 59 ± 11 years, and the mean estimated glomerular filtration rate (eGFR, ± SD) was 43 ± 17 mL/min per 1.73 m2. Median (interquartile range) values of plasma prorenin and renin at study entry were 4.4 (2.1, 8.8) ng/mL and 2.0 (0.8, 5.9) ng/dL, respectively. Prorenin and renin were positively correlated (Spearman correlation 0.51, p < 0.001) with each other. Women and non-Hispanic blacks had lower prorenin and renin values at year 1. Diabetes, lower eGFR, and use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, statins, and diuretics were associated with higher levels. Prorenin and renin decreased by a mean of 2 and 5% per year, respectively. Non-Hispanic black race and eGFR <30 mL/min/1.73 m2 at year 1 predicted a steeper decrease in prorenin and renin over time. In addition, each increase in urinary sodium excretion by 2 SDs at year 1 increased prorenin and renin levels by 4 and 5% per year, respectively. DISCUSSION/CONCLUSIONS: The cross-sectional clinical factors associated with prorenin and renin values were similar. Overall, both plasma prorenin and renin concentrations decreased over the years, particularly in those with severe CKD at study entry.

Clinical events and patient-reported outcome measures during CKD progression: findings from the Chronic Renal Insufficiency Cohort Study.

BACKGROUND: Patients with chronic kidney disease (CKD) face risks of not only end-stage kidney disease (ESKD), cardiovascular disease (CVD) and death, but also decline in kidney function, quality of life (QOL) and mental and physical well-being. This study describes the multidimensional trajectories of CKD using clinical events, kidney function and patient-reported outcome measures (PROMs). We hypothesized that more advanced CKD stages would associate with more rapid decline in each outcome. METHODS: Among 3939 participants enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study, we evaluated multidimensional disease trajectories by G- and A-stages of enrollment estimated glomerular filtration rate (eGFR) and albuminuria, respectively. These trajectories included clinical events (ESKD, CVD, heart failure and death), eGFR decline and PROMs [kidney disease QOL (KDQOL) burden, effects and symptoms questionnaires, as well as the 12-item short form mental and physical component summaries]. We also evaluated a group-based multitrajectory model to group participants on the basis of longitudinal PROMs and compared group assignments by enrollment G- and A-stage. RESULTS: The mean participant age was 58 years, 45% were women, mean baseline eGFR was 44 mL/min/1.73 m2 and median urine albumin:creatinine ratio was 52 mg/g. The incidence of all clinical events was greater and eGFR decline was faster with more advanced G- and A-stages. While baseline KDQOL and physical component measures were lower with more advanced G- and A-stage of CKD, changes in PROMs were inconsistently related to the baseline CKD stage. Groups formed on PROM trajectories were fairly distinct from existing CKD staging (observed agreement 60.6%) and were associated with the risk of ESKD, CVD, heart failure and death. CONCLUSIONS: More advanced baseline CKD stage was associated with a higher risk of clinical events and faster eGFR decline, and was only weakly related to changes in patient-reported metrics over time.

Chronic kidney disease, atherosclerotic plaque characteristics on carotid magnetic resonance imaging, and cardiovascular outcomes.

BACKGROUND: It is unclear whether faster progression of atherosclerosis explains the higher risk of cardiovascular events in CKD. The objectives of this study were to 1. Characterize the associations of CKD with presence and morphology of atherosclerotic plaques on carotid magnetic resonance imaging (MRI) and 2. Examine the associations of baseline CKD and carotid atherosclerotic plaques with subsequent cardiovascular events. METHODS: In a subgroup (N = 465) of Systolic Blood Pressure Intervention Trial. (SPRINT) participants, we measured carotid plaque presence and morphology at baseline and after 30-months with MRI. We examined the associations of CKD (baseline eGFR < 60 ml/min/1.73m2) with progression of carotid plaques and the SPRINT cardiovascular endpoint. RESULTS: One hundred and ninety six (42%) participants had CKD. Baseline eGFR in the non-CKD and CKD subgroups were 77 ± 14 and 49 ± 8 ml/min/1.73 m2, respectively. Lipid rich necrotic-core plaque was present in 137 (29.5%) participants. In 323 participants with both baseline and follow-up MRI measurements of maximum wall thickness, CKD was not associated with progression of maximum wall thickness (OR 0.62, 95% CI 0.36 to 1.07, p = 0.082). In 96 participants with necrotic core plaque at baseline and with a valid follow-up MRI, CKD was associated with lower odds of progression of necrotic core plaque (OR 0.41, 95% CI 0.17 to 0.95, p = 0.039). There were 28 cardiovascular events over 1764 person-years of follow-up. In separate Cox models, necrotic core plaque (HR 2.59, 95% CI 1.15 to 5.85) but not plaque defined by maximum wall thickness or presence of a plaque component (HR 1.79, 95% CI 0.73 to 4.43) was associated with cardiovascular events. Independent of necrotic core plaque, CKD (HR 3.35, 95% CI 1.40 to 7.99) was associated with cardiovascular events. CONCLUSIONS: Presence of necrotic core in carotid plaque rather than the presence of plaque per se was associated with increased risk of cardiovascular events. We did not find CKD to be associated with faster progression of necrotic core plaques, although both were independently associated with cardiovascular events. Thus, CKD may contribute to cardiovascular disease principally via mechanisms other than atherosclerosis such as arterial media calcification or stiffening. TRIAL REGISTRATION: NCT01475747 , registered on November 21, 2011.

Commentary on the KDIGO 2021 Clinical Practice Guideline for the Management of Blood Pressure in CKD.

PURPOSE OF REVIEW: To summarize and explain the new guideline on blood pressure (BP) management in chronic kidney disease (CKD) published by Kidney Disease: Improving Global Outcomes (KDIGO), an independent global nonprofit organization which develops and implements evidence-based clinical practice guidelines in kidney disease. KDIGO issued its first clinical practice guideline for the Management of Blood Pressure (BP) in Chronic Kidney Disease (CKD) for patients not receiving dialysis in 2012 and now updated the guideline in 2021. RECENT FINDINGS: Recommendations in this update were developed based on systematic literature reviews and appraisal of the quality of the evidence and strength of recommendation following the "Grading of Recommendations Assessment, Development and Evaluation" (GRADE) approach. The updated guideline includes five chapters covering BP measurement techniques, lifestyle interventions for lowering BP, and management of BP in three target populations, namely adults (with and without diabetes), kidney transplant recipients, and children. A dedicated chapter on BP measurement emphasizing standardized preparation and measurement protocols for office BP measurement is a new addition, following protocols used in large randomized trials of BP targets with pivotal clinical outcomes. Based on the available evidence, and in particular in the CKD subgroup of the SPRINT trial, the 2021 guideline suggests a systolic BP target of <120 mm Hg, based on standardized measurements, for most individuals with CKD not receiving dialysis, with the exception of kidney transplant recipients and children. This recommendation is strictly contingent on the measurement of BP using standardized office readings and not routine office readings.

A Randomized Trial Comparing the Safety, Adherence, and Pharmacodynamics Profiles of Two Doses of Sodium Bicarbonate in CKD: the BASE Pilot Trial.

BACKGROUND: Oral sodium bicarbonate (NaHCO3) may preserve kidney function in CKD, even if initiated when serum bicarbonate concentration is normal. Adequately powered trials testing this hypothesis have not been conducted, partly because the best dose for testing is unknown. METHODS: This multicenter pilot trial assessed the safety, tolerability, adherence, and pharmacodynamics of two doses of NaHCO3 over 28 weeks in adults with eGFR 20-44 or 45-59 ml/min per 1.73 m2 with urinary albumin/creatinine (ACR) ≥50 mg/g and serum bicarbonate 20-28 meq/L. We randomly assigned 194 participants from ten clinical sites to receive higher-dose (HD-NaHCO3; 0.8 meq/kg of lean body wt per day; n=90) or lower-dose (LD-NaHCO3; 0.5 meq/kg of lean body wt per day; n=52) NaHCO3 or matching placebo (n=52). The dose was adjusted depending on side effects. The prescribed dose at week 28 was the primary outcome; a dose was considered acceptable for a full-scale trial if ≥67% of participants were on full-dose and ≥80% were on ≥25% of the per-protocol dose. RESULTS: Mean±SD baseline eGFR was 36±9 ml/min per 1.73 m2, serum bicarbonate was 24±2 meq/L, and median (IQR) ACR was 181 (25-745) mg/g. Both doses were well tolerated without significant changes in BP, weight, or serum potassium. The proportions of adverse events and hospitalizations were similar across the groups. Consequently, 87% in HD-NaHCO3, 96% in LD-NaHCO3, and 87% in placebo were on full dose at week 28; and 91% in HD-NaHCO3, 98% in LD-NaHCO3, and 92% in placebo were on ≥25% of the per-protocol dose. Mean urinary ammonium excretion was 25% lower and serum bicarbonate concentration was 1.3 meq/L higher in HD-NaHCO3 compared with LD-NaHCO3 at week 28. However, mean ACR increased by 12% in the lower-dose group and 30% in the higher-dose group. CONCLUSIONS: Both NaHCO3 doses were well tolerated over 28 weeks with no significant difference in adverse events or hospitalization compared with placebo. The higher dose lowered urinary ammonium excretion and increased serum bicarbonate more than the lower dose but was associated with a greater increase in ACR. The higher 0.8 meq/kg of lean body wt per day dose of NaHCO3 may be a reasonable choice for future trials.

Cost-Effectiveness of Intensive versus Standard Blood-Pressure Control.

BACKGROUND: In the Systolic Blood Pressure Intervention Trial (SPRINT), adults at high risk for cardiovascular disease who received intensive systolic blood-pressure control (target, <120 mm Hg) had significantly lower rates of death and cardiovascular disease events than did those who received standard control (target, <140 mm Hg). On the basis of these data, we wanted to determine the lifetime health benefits and health care costs associated with intensive control versus standard control. METHODS: We used a microsimulation model to apply SPRINT treatment effects and health care costs from national sources to a hypothetical cohort of SPRINT-eligible adults. The model projected lifetime costs of treatment and monitoring in patients with hypertension, cardiovascular disease events and subsequent treatment costs, treatment-related risks of serious adverse events and subsequent costs, and quality-adjusted life-years (QALYs) for intensive control versus standard control of systolic blood pressure. RESULTS: We determined that the mean number of QALYs would be 0.27 higher among patients who received intensive control than among those who received standard control and would cost approximately $47,000 more per QALY gained if there were a reduction in adherence and treatment effects after 5 years; the cost would be approximately $28,000 more per QALY gained if the treatment effects persisted for the remaining lifetime of the patient. Most simulation results indicated that intensive treatment would be cost-effective (51 to 79% below the willingness-to-pay threshold of $50,000 per QALY and 76 to 93% below the threshold of $100,000 per QALY), regardless of whether treatment effects were reduced after 5 years or persisted for the remaining lifetime. CONCLUSIONS: In this simulation study, intensive systolic blood-pressure control prevented cardiovascular disease events and prolonged life and did so at levels below common willingness-to-pay thresholds per QALY, regardless of whether benefits were reduced after 5 years or persisted for the patient's remaining lifetime. (Funded by the National Heart, Lung, and Blood Institute and others; SPRINT ClinicalTrials.gov number, NCT01206062 .).