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Background Recent evidence suggests the systemic accumulation of by-products of gut microbes contributes to cardiovascular morbidity in patients with CKD. Limiting the generation of toxic bacterial by-products by manipulating the intestinal microbiota may be a novel strategy for reducing cardiovascular disease in CKD. Rifaximin is a minimally absorbed, oral antibiotic that targets intestinal pathogens and is commonly used as chronic therapy for the prevention of encephalopathy in patients with cirrhosis. Methods We conducted a randomized, double-blinded, placebo-controlled trial to determine the effect of a 10-day course of oral rifaximin 550 mg BID versus placebo on circulating concentrations of gut-derived cardiovascular toxins and proinflammatory cytokines in patients with stage 3–5 CKD (n=38). The primary clinical outcome was change in serum trimethylamine N-oxide (TMAO) concentrations from baseline to study end. Secondary outcomes included change in serum concentrations of p-cresol sulfate, indoxyl sulfate, kynurenic acid, deoxycholic acid, and inflammatory cytokines (C-reactive protein, IL-6, IL-1β), and change in composition and diversity of fecal microbiota. Results A total of 19 patients were randomized to each of the rifaximin and placebo arms, with n=17 and n=14 completing both study visits in these respective groups. We observed no difference in serum TMAO change (post-therapy minus baseline TMAO) between the rifaximin and placebo groups (mean TMAO change −3.9±15.4 for rifaximin versus 0.5±9.5 for placebo, P=0.49). Similarly, we found no significant change in serum concentrations for p-cresol sulfate, indoxyl sulfate, kynurenic acid, deoxycholic acid, and inflammatory cytokines. We did observe differences in colonic bacterial communities, with the rifaximin group exhibiting significant decreases in bacterial richness (Chao1, P=0.02) and diversity (Shannon H, P=0.05), along with altered abundance of several bacterial genera. Conclusions Short-term rifaximin treatment failed to reduce gut-derived cardiovascular toxins and inflammatory cytokines in patients with CKD. Clinical Trial registry name and registration number Rifaximin Therapy in Chronic Kidney Disease, NCT02342639

BACKGROUND: Thrombocytopenia is a risk factor for morbidity and mortality in critically ill patients, and is common following cardiopulmonary bypass (CPB). In this study, we evaluate whether thrombocytopenia following CPB is an independent risk factor for post-operative morbidity and mortality. METHODS: We retrospectively evaluated 1,364 patients requiring CPB at University of Colorado Hospital between January 2011 and May 2016. Platelet nadir, absolute change in platelets, and percent change in platelets were modeled as continuous variables. Patients with post-operative thrombocytopenia (defined a nadir

Aims Arterial stiffness increases with both advancing age and chronic kidney disease (CKD) and may contribute to kidney function decline, but evidence is inconsistent. We hypothesized that greater baseline arterial stiffness (assessed as pulse pressure (PP) and carotid-femoral pulse-wave velocity CFPWV)) was independently associated with kidney disease progression over the follow-up period (3.8 years) in the Systolic Blood Pressure Intervention Trial (SPRINT). Materials and methods 8,815 SPRINT participants were included in the analysis of PP. 592 adults who participated in a SPRINT ancillary study that measured CFPWV were included in subgroup analyses. Cox proportional hazards analysis was used to examine the association between PP and time to kidney disease progression endpoints: (A) incident estimated glomerular filtration rate (eGFR) l 60 mL/min/1.73m2 in non-CKD participants at baseline; (B) 50% decline in eGFR, initiation of dialysis, or transplant in those with baseline CKD. Mixed model analyses examined the association of baseline PP/CFPWV with follow-up eGFR. Results and conclusion Mean ± SD age was 68 ± 10 years, baseline PP was 62 ± 14 mmHg, and CFPWV was 10.8 ± 2.7 m/s. In the fully adjusted model, PP ≥ median was associated with an increased hazard of kidney disease progression endpoints (HR: 1.93 (1.43 - 2.61)). The association remained significant in individuals without (2.05 (1.47 - 2.87)) but not with baseline CKD (1.28 (0.55 - 2.65)). In fully adjusted models, higher baseline PP associated with eGFR decline (p l 0.0001 (all, CKD, non-CKD)), but baseline CFPWV did not. Among older adults at high risk for cardiovascular events, baseline PP was associated with kidney disease progression.

Lower serum bicarbonate levels are associated with an increased risk of kidney disease progression. Whether lower serum bicarbonate levels are associated with an increased risk of developing acute kidney injury (AKI) is unclear. We included 8393 patients from the Systolic Blood Pressure Intervention Trial (SPRINT) that had baseline serum bicarbonate levels and complete data available. AKI was a predetermined adjudicated adverse event that was determined by hospital admission and discharge records with AKI as a recorded diagnosis. Serum bicarbonate was examined in clinically significant cutoffs ≤ 24, 25–28 and > 28 mEq/L, with 25–28 mEq/L as the reference group. Cox proportional hazard models were used to examine the association between serum bicarbonate and development of AKI. The mean (SD) age, estimated glomerular filtration rate (eGFR), and serum bicarbonate level at baseline were 68 (9) years, 77 (23) ml/min/1.73m2 and 26.3 (2.6) mEq/L, respectively. Participants with serum bicarbonate levels ≤ 24 mEq/L were more likely to be male and to have lower baseline eGFR. After a median follow-up time of 3.3 years, 293 participants developed AKI. More patients in the lower bicarbonate group developed AKI (6.1% vs 2.8% in the 25–28 mEq/L and 2.1% in the > 28 mEq/L). A bicarbonate level ≤ 24 mEq/L was associated with a significantly increased risk of AKI compared to those with a bicarbonate level of 25–28 mEq/L after full adjustment (HR 1.42, 95% CI 1.1–1.8). Lower serum bicarbonate levels are an independent risk factor for the development of AKI.

Rationale & Objective Elevated levels of deoxycholic acid (DCA) are associated with adverse outcomes and may contribute to vascular calcification in patients with chronic kidney disease (CKD). We tested the hypothesis that elevated levels of DCA were associated with increased risks of cardiovascular disease, CKD progression, and death in patients with CKD. Study Design Prospective observational cohort study. Setting & Participants We included 3,147 Chronic Renal Insufficiency Cohort study participants who had fasting DCA levels. The average age was 59 ± 11 years, 45.3% were women, 40.6% were African American, and the mean estimated glomerular filtration rate was 42.5 ± 16.0 mL/min/1.73 m2. Predictor Fasting DCA levels in Chronic Renal Insufficiency Cohort study participants. Outcomes Risks of atherosclerotic and heart failure events, end-stage kidney disease (ESKD), and all-cause mortality. Analytical Approach We used Tobit regression to identify predictors of DCA levels. We used Cox regression to examine the association between fasting DCA levels and clinical outcomes. Results The strongest predictors of elevated DCA levels in adjusted models were increased age and nonuse of statins. The associations between log-transformed DCA levels and clinical outcomes were nonlinear. After adjustment, DCA levels above the median were independently associated with higher risks of ESKD (HR, 2.67; 95% CI, 1.51-4.74) and all-cause mortality (HR, 2.13; 95% CI, 1.25-3.64). DCA levels above the median were not associated with atherosclerotic and heart failure events, and DCA levels below the median were not associated with clinical outcomes. Limitations We were unable to measure DCA longitudinally or in urinary or fecal samples, and we were unable to measure other bile acids. We also could not measure many factors that affect DCA levels. Conclusions In 3,147 participants with CKD stages 2-4, DCA levels above the median were independently associated with ESKD and all-cause mortality., Graphical abstract

Vascular calcification (VC) is common in chronic kidney disease, increases in prevalence as patients progress to end-stage renal disease, and is significantly associated with mortality. VC is a complex and highly regulated process similar to bone formation whereby hydroxyapatite crystals deposit in the intimal or medial layer of arteries. Mineral bone abnormalities are common in chronic kidney disease; reduction in glomerular filtration rate and changes in vitamin D, parathyroid hormone, and fibroblast growth factor 23 result in the dysregulation of phosphorus and calcium metabolism. Cell culture studies, animal models, and observational and clinical studies all suggest this abnormal mineral metabolism plays a role in the initiation and progression of VC in kidney disease. This review will focus on these mineral bone abnormalities and how they may contribute to mechanisms that induce VC in kidney disease.

Guidelines recommend that patients treated with continuous renal replacement therapy be delivered an effluent dose of 20 to 25 mL/kg/h. There is debate, especially at the extremes of body mass index, as to whether actual or ideal body weight (IBW) should be used in these dose calculations. A middle-aged woman with severe anorexia presented with 48 hours of altered mental status. Laboratory tests showed severe metabolic acidosis necessitating intubation, which was ultimately found to be due to nonprescribed use of metformin for weight loss. The patient became anuric and was initiated on continuous venovenous hemodialysis. Due to refractory acidosis, the modality was converted to continuous venovenous hemodiafiltration by adding postfilter hypertonic bicarbonate solution. Based on changes in sodium and bicarbonate levels over 4 hours with hypertonic bicarbonate solution, we were able to calculate an “effective” volume of distribution for this severely underweight patient. Our calculations suggest that IBW gives a better approximation of effective volume of distribution than actual body weight in a severely underweight woman. Inadequate effluent flow rate calculated based on actual rather than IBW may lead to insufficient correction of metabolic derangements in extremely underweight patients. Index Words: Acute kidney injury (AKI), continuous renal replacement therapy (CRRT), dialysis dose, volume of distribution

Thrombocytopenia is common in critically ill patients with severe acute kidney injury and may be worsened by the use of renal replacement therapy. In this study, we evaluate the effects of renal replacement therapy on subsequent platelet values, the prognostic significance of a decrease in platelets, and potential risk factors for platelet decreases.Post hoc analysis of the Acute Renal Failure Trial Network Study.The Acute Renal Failure Trial Network study was a multicenter, prospective, randomized, parallel-group trial of two strategies for renal replacement therapy in critically ill patients with acute kidney injury conducted between November 2003 and July 2007 at 27 Veterans Affairs and university-affiliated medical centers.The Acute Renal Failure Trial Network study evaluated 1,124 patients with severe acute kidney injury requiring renal replacement therapy.Predictor variables were thrombocytopenia at initiation of renal replacement therapy and platelet decrease following renal replacement therapy initiation.Outcomes were mortality at 28 days, 60 days, and 1 year, renal recovery, renal replacement therapy free days, ICU-free days, and hospital-free days. Baseline thrombocytopenia in patients requiring renal replacement therapy was associated with increased mortality and was also associated with lower rates of renal recovery. A decrease in platelet values following renal replacement therapy initiation was associated with increased mortality. Continuous renal replacement therapy was not an independent predictor of worsening thrombocytopenia compared with those treated with intermittent hemodialysis.Baseline thrombocytopenia and platelet decrease following renal replacement therapy initiation were associated with increased mortality, and baseline thrombocytopenia was associated with decreased rates of renal recovery. Continuous renal replacement therapy did not decrease platelets compared with hemodialysis.

AKI is defined by an abrupt decrease in kidney function and is associated with significant morbidity and mortality, including kidney disease progression and higher cardiovascular disease risk ([1][1]). Greater arterial stiffness is also associated with higher risk for kidney function decline and

Fibroblast growth factor 23 (FGF23) is elevated in kidney disease compared to healthy individuals, and the highest FGF23 levels are observed in end-stage kidney disease. FGF23 rises early in the course of chronic kidney disease (CKD), before the development of secondary hyperparathyroidism. FGF23 is now viewed as the central actor in the biochemical abnormalities associated with CKD–mineral bone disorder. As glomerular filtration declines and renal phosphorus excretion is reduced, increasing FGF23 levels are important to maintain normal levels of circulating phosphorus. However, elevated FGF23 levels inhibit 1α-hydroxylase and reduce active vitamin D contributing to the development of secondary hyperparathyroidism. FGF23 also contributes to calcium homeostasis and iron and erythropoietin regulation and is associated with inflammation. FGF23 is strongly associated with adverse clinical outcomes in kidney disease, including cardiovascular disease and death; however, it is uncertain if this association is causal or if FGF23 is simply a marker of advanced disease.

Although often considered to be a disease of adults, complications of autosomal dominant polycystic kidney disease (ADPKD) begin in childhood. While the hallmark of ADPKD is the development and continued growth of multiple renal cysts that ultimately result in loss of kidney function, cardiovascular complications are the leading cause of death among affected patients. Vascular dysfunction (endothelial dysfunction and large elastic artery stiffness) is evident very early in the course of the disease and appears to involve increased oxidative stress and inflammation. Treatment options to prevent cardiovascular disease in adults with ADPKD are limited, thus childhood may represent a key therapeutic window. Curcumin is a safe, naturally occurring polyphenol found in the Indian spice turmeric. This spice has a unique ability to activate transcription of key antioxidants, suppress inflammation, and reduce proliferation. Here we describe our ongoing randomized, placebo-controlled, double-blind clinical trial to assess the effect of curcumin therapy on vascular function and kidney growth in 68 children and young adults age 6–25 years with ADPKD. Baseline demographic, vascular, and kidney volume data are provided. This study has the potential to establish a novel, safe, and facile therapy for the treatment of arterial dysfunction, and possibly renal cystic disease, in an understudied population of children and young adults with ADPKD., Highlights • Evaluating a strategy to intervene early in the course of ADPKD. • Assessing two major contributors to arterial dysfunction and CVD risk in ADPKD. • Curcumin is a novel nutraceutical that is an safe, naturally occurring, and facile. • Using a translational approach is used to assess physiological mechanisms. • Gaining exploratory evidence on the efficacy of curcumin to slow kidney growth.

BACKGROUND: Increased arterial stiffness and vascular endothelial dysfunction are important nontraditional cardiovascular risk factors evident in patients with CKD. Vascular oxidative stress and inflammation may contribute to vascular dysfunction in CKD, but direct evidence is lacking. METHODS: We assessed carotid-femoral pulse-wave velocity (arterial stiffness) and brachial artery flow-mediated dilation (vascular endothelial function) in participants with moderate-to-severe CKD (eGFR 15–59 ml/min per 1.73 m(2)) and in healthy controls. Change in brachial artery flow-mediated dilation after an acute infusion of ascorbic acid to inhibit vascular oxidative stress (versus saline) was also measured. Protein expression of vascular endothelial cells collected from a peripheral vein and ELISAs to assess circulating markers were also performed. RESULTS: A total of 64 participants with CKD (mean±SD, 65±8 years) and 17 healthy controls (60±5 years) were included. Carotid-femoral pulse-wave velocity was greater in participants with CKD compared with healthy controls (1071±336 versus 732±128 cm/s; P

BACKGROUND/OBJECTIVES Chronic kidney disease (CKD) is associated with frailty. Fibroblast growth factor 23 (FGF23) is elevated in CKD and associated with frailty among non-CKD older adults and individuals with human immunodeficiency virus. Whether FGF23 is associated with frailty and falls in CKD is unknown. DESIGN Cross-sectional and longitudinal observational study. SETTING Systolic Blood Pressure Intervention Trial (SPRINT), a randomized trial evaluating standard (systolic blood pressure [SBP]

Patients with CKD exhibit a disproportionate burden of cardiovascular mortality, which likely stems from the presence of unique, nontraditional risk factors that accompany deteriorating kidney function. Mounting evidence suggests that alterations to the intestinal microbiome in CKD may serve as one such risk factor. The human intestinal tract is home to >100 trillion micro-organisms made up of a collection of commensal, symbiotic, and pathogenic species. These species along with their local environment constitute the intestinal microbiome. Patients with CKD show intestinal dysbiosis, an alteration of the gut micro-organism composition and function. Recent evidence links byproducts of intestinal dysbiosis to vascular calcification, atherosclerosis formation, and adverse cardiovascular outcomes in CKD. CKD-associated intestinal dysbiosis may also be accompanied by defects in intestinal barrier function, which could further enhance the negative effects of pathogenic intestinal bacteria in the human host. Thus, intestinal dysbiosis, defective intestinal barrier function, and a reduced capacity for clearance by the kidney of absorbed bacterial byproducts may all potentiate the development of cardiovascular disease in CKD. This narrative review focuses on microbiome-mediated mechanisms associated with CKD that may promote atherosclerosis formation and cardiovascular disease. It includes (1) new data supporting the hypothesis that intestinal barrier dysfunction leads to bacterial translocation and endotoxemia that potentiate systemic inflammation, (2) information on the accumulation of dietary-derived bacterial byproducts that stimulate pathways promoting atheromatous changes in arteries and cardiovascular disease, and (3) potential interventions. Despite great scientific interest in and a rapidly growing body of literature on the relationship between the microbiome and cardiovascular disease in CKD, many important questions remain unanswered.

BACKGROUND: Acute kidney injury (AKI) and infection are common complications after pediatric cardiac surgery. No pediatric study has evaluated for an association between postoperative AKI and infection. The objective of this study was to determine if AKI in neonates after cardiopulmonary bypass was associated with the development of a postoperative infection. METHODS: We performed a single center retrospective chart review from January 2009 to December 2015 of neonates (age ≤ 30 days) undergoing the Norwood procedure. AKI was defined by the modified neonatal Kidney Disease Improving Global outcomes serum creatinine criteria using (1) measured serum creatinine and (2) creatinine corrected for fluid balance on postoperative days 1–4. Infection, (culture positive or presumed), must have occurred after a diagnosis of AKI and within 60 days of surgery. RESULTS: Ninety-five patients were included, of which postoperative infection occurred in 42 (44%). AKI occurred in 38 (40%) and 42 (44%) patients by measured serum creatinine and fluid overload corrected creatinine, respectively, and was most commonly diagnosed on postoperative day 2. The median time to infection from the time of surgery and AKI was 7 days (IQR 5–14 days) and 6 days (IQR 3–13 days), respectively. After adjusting for confounders, the odds of a postoperative infection were 3.64 times greater in patients with fluid corrected AKI (95% CI, 1.36–9.75; p = 0.01). CONCLUSIONS: Fluid corrected AKI was independently associated with the development of a postoperative infection. These findings support the notion that AKI is an immunosuppressed state that increases the risk of infection.

Background: Dietary sodium may influence cognitive function through its effects on cerebrovascular function and cerebral blood flow. Methods: The aim of this study was to evaluate the association of dietary sodium intake with cognitive decline in community-dwelling older adults. We also evaluated the associations of dietary potassium and sodium:potassium intake with cognitive decline, and associations of these nutrients with micro- and macro-structural brain magnetic resonance imaging (MRI) indices. In all, 1,194 participants in the Health Aging and Body Composition study with measurements of dietary sodium intake (food frequency questionnaire [FFQ]) and change in the modified Mini Mental State Exam (3MS) were included. Results: The age of participants was 74 ± 3 years with a mean dietary sodium intake of 2,677 ± 1,060 mg/day. During follow-up (6.9 ± 0.1 years), 340 (28%) had a clinically significant decline in 3MS score (≥1.5 SD of mean decline). After adjustment, dietary sodium intake was not associated with odds of cognitive decline (OR 0.96, 95% CI 0.50–1.84 per doubling of sodium). Similarly, potassium was not associated with cognitive decline; however, higher sodium:potassium intake was associated with increased odds of cognitive decline (OR 2.02 [95% CI 1.01–4.03] per unit increase). Neither sodium or potassium alone nor sodium:potassium were associated with micro- or macro-structural brain MRI indices. These results are limited by the use of FFQ. Conclusions: In community-dwelling older adults, higher sodium:potassium, but not sodium or potassium intake alone, was associated with decline in cognitive function, with no associations observed with micro- and macro-structural brain MRI indices. These findings do not support reduction dietary sodium/increased potassium intake to prevent cognitive decline with aging.

Background Shunt nephritis is a rare, reversible immune-complex mediated complication of cerebrospinal fluid (CSF) shunt infection that can progress to end-stage renal disease and even death if diagnosis is delayed. Case Description The present case report details the manifestation and clinical course of shunt nephritis in a 50-year-old patient who presented with symptoms of nephrotic syndrome 30 years after ventriculojugular shunt placement. Diagnosis was delayed due to initial negative CSF and blood cultures, but a later CSF culture was positive for Propionibacterium acnes. After treatment with intravenous antibiotics and complete removal of shunt with subsequent replacement with a new ventriculoperitoneal shunt, the nephritic symptoms resolved, but the patient continued to have reduced kidney function consistent with stage IIIa chronic kidney disease. Conclusion This case emphasizes the clinical importance of having a high index of suspicion in patients with a ventricular shunt who present with symptoms consistent with nephritis, even in the setting of negative cultures and delayed presentation.

BACKGROUND: Fibroblast growth factor 23 (FGF-23) is a hormone that regulates phosphorus levels and vitamin D metabolism. Previous studies have shown FGF-23 to be a risk factor for incident end-stage renal disease; however, there are less data on the association of FGF-23 with earlier kidneyrelated outcomes. METHODS: Serum FGF-23 was assayed using an intact ELISA assay in 2,496 participants of the Healthy Aging and Body Composition Study, a cohort of well-functioning older adults. Kidney function was estimated by assaying cystatin C at baseline and years 3 and 10. The associations between FGF-23 and decline in kidney function (defined by estimated glomerular filtration rate (eGFR) decline ≥30% or ≥3 mL/min/year) and incident chronic kidney disease (CKD; incident eGFR 3 mL/min/year decline, and 536 with incident CKD. In fully adjusted continuous models, doubling of FGF-23 concentrations was not associated with kidney function decline (OR [95% CI] = 0.98 [0.82–1.19] for ≥30% decline and OR 1.17 [95% CI 1.00–1.37] for ≥3 mL/min/ year decline), or incident CKD (incident rate ratio [IRR] 1.05 [95% CI 0.91–1.22]). In adjusted quartile analysis, the highest quartile of FGF-23 was significantly associated with incident CKD (IRR 1.27 [95% CI 1.02–1.58] for highest vs. lowest quartile). CONCLUSION: Higher FGF-23 concentrations were not consistently associated with decline in kidney function or incident CKD in community-dwelling older adults.

IMPORTANCE: Guidelines restricting use of calcium-based phosphate binders in all patients with end-stage renal disease owing to their potential contribution to increased cardiovascular risk shifted prescribing from calcium acetate toward the costlier sevelamer carbonate products. OBJECTIVE: To compare cardiovascular events and mortality between patients with end-stage renal disease (ESRD) undergoing hemodialysis receiving sevelamer vs calcium acetate in real-world practice. DESIGN, SETTING, AND PARTICIPANTS: An observational cohort study was conducted using the United States Renal Data System linked to Medicare claims data (May 1, 2012, to December 31, 2013). Data analysis was performed from October 2017 to September 2018. Participants included patients 65 years or older with ESRD within 180 days after starting hemodialysis (sevelamer, 2647; calcium acetate, 2074). EXPOSURES: New use of sevelamer (calcium-free phosphate binder) vs calcium acetate (calcium-based phosphate binder). MAIN OUTCOMES AND MEASURES: Hazard ratios (HRs) with 95% CIs were estimated for fatal or nonfatal cardiovascular events (myocardial infarction or ischemic stroke: primary outcome) and all-cause mortality (secondary outcome) using Cox proportional hazards regression with fine stratification on the propensity score to control for potential confounders, including phosphorus and calcium levels. RESULTS: After propensity score weighting, 2639 patients initiating sevelamer treatment (1184 men [44.9%]; mean [SD] age, 75.6 [6.9] years) and 2065 patients initiating calcium acetate treatment (930 men [45.0%]; mean [SD] age, 75.5 [7.1] years) were included in the analysis. Crude incidence rates (IRs) for cardiovascular events of 458 per 1000 person-years for sevelamer and 464 per 1000 person-years for calcium acetate were observed. After propensity score fine-stratification weighting, HRs of 0.96 (95% CI, 0.84-1.10) for cardiovascular events were observed. Results were consistent within subgroups of age (

BackgroundSevere acute kidney injury (AKI) is associated with subsequent infection. Whether AKI followed by a return to baseline creatinine is associated with incident infection is unknown.ObjectiveWe hypothesized that risk of both short and long term infection would be higher among patients with AKI and return to baseline creatinine than in propensity score matched peers without AKI in the year following a non-infectious hospital admission.DesignRetrospective, propensity score matched cohort study.ParticipantsWe identified 494 patients who were hospitalized between January 1, 1999 and December 31, 2009 and had AKI followed by return to baseline creatinine. These were propensity score matched to controls without AKI.Main measuresThe predictor variable was AKI defined by International Classification of Diseases, Ninth Revision (ICD-9) codes and by the Kidney Disease Improving Global Outcomes definition, with return to baseline creatinine defined as a decrease in serum creatinine level to within 10% of the baseline value within 7 days of hospital discharge. The outcome variable was incident infection defined by ICD-9 code within 1 year of hospital discharge.ResultsAKI followed by return to baseline creatinine was associated with a 4.5-fold increased odds ratio for infection (odds ratio 4.53 [95% CI, 2.43-8.45]; pConclusionAmong patients from an integrated health care delivery system, non-infectious AKI followed by return to baseline creatinine was associated with an increased odds ratio for infection in the year following discharge.

Background: Long-term patterns of fibroblast growth factor 23 (FGF23) are poorly characterized among dialysis patients. Objectives: To identify different FGF23 trajectories and determine clinical factors that predict distinct FGF23 trajectories and whether FGF23 trajectories differ in regard to their associations with all-cause mortality among prevalent hemodialysis patients. Methods: The HEMO study was a randomized multicenter study evaluating the effects of high-dose vs. standard-dose and high-flux vs. low-flux hemodialysis on mortality. We measured intact FGF23 levels in stored serum samples at baseline and annually among 919 HEMO participants and identified FGF23 trajectories using group-based modeling. Logistic regression determined predictors of trajectories. Cox regression models evaluated the association between trajectory and all-cause mortality. Results: We identified 5 distinct FGF23 trajectory groups during the initial 24 months: low stable, low increasing, elevated increasing, elevated decreasing, and elevated stable. In multivariable models, diabetes, high dose dialysis, no venous catheter, low serum calcium, phosphorus, and interleukin-6, no vitamin D analog use, and greater residual kidney function were associated with the low stable trajectory group compared to the elevated stable group. High flux dialysis, no venous catheter, and low serum phosphorus and 25-hydroxyvitamin D were associated with the elevated decreasing trajectory group compared to the elevated stable group. After full adjustment, the low stable trajectory group was associated with reduced mortality (hazard ratio [HR] 0.61; 95% CI ­0.41–0.91) compared to the elevated stable trajectory group. Conclusions: We identified 5 distinct FGF23 trajectories over 24 months among HEMO study participants including a decreasing trajectory. The low stable FGF23 trajectory was associated with a reduced HR of all-cause mortality.

Summary: Chronic kidney disease mineral bone disorder (CKD-MBD) is common in end-stage renal disease and is associated with an increased risk of cardiovascular morbidity and mortality. Mainstays of treatment include decreasing serum phosphorus level toward the normal range with dietary interventions and phosphate binders and treating increased parathyroid hormone levels with activated vitamin D and/or calcimimetics. There is significant variation in serum levels of mineral metabolism markers, intestinal absorption of phosphorus, and therapeutic response among individual patients and subgroups of patients with end-stage renal disease. This variation may be partly explained by polymorphisms in genes associated with calcium and phosphorus homeostasis such as the calcium-sensing receptor gene, the vitamin D–binding receptor gene, and genes associated with vascular calcification. In this review, we discuss how personalized medicine may be used for the management of CKD-MBD and how it ultimately may lead to improved clinical outcomes. Although genetic variants may seem attractive targets to tailor CKD-MBD therapy, complete understanding of how these polymorphisms function and their clinical utility and applicability to personalized medicine need to be determined.

Background and objectives Both increased arterial stiffness and vascular endothelial dysfunction are evident in patients with autosomal dominant polycystic kidney disease, even early in the course of the disease when kidney function in preserved. Vascular dysfunction in autosomal dominant polycystic kidney disease is thought to be related to vascular oxidative stress and inflammation, but direct evidence is lacking. Design, setting, participants, & measurements We assessed carotid-femoral pulse-wave velocity (arterial stiffness) and brachial artery flow-mediated dilation (vascular endothelial function) in participants with early-stage autosomal dominant polycystic kidney disease (eGFR≥60 ml/min per 1.73 m2) and a history of controlled hypertension and in healthy controls. Brachial artery flow-mediated dilation was also assessed after infusion of ascorbic acid to inhibit vascular oxidative stress compared with saline. Vascular endothelial cells were collected from a peripheral vein to measure expression of proteins, and circulating markers were also assessed by ELISA or liquid chromatography-tandem mass spectrometry. Results In total, 61 participants with autosomal dominant polycystic kidney disease (34±9 years old [mean±SD]) and 19 healthy controls (30±5 years old) were studied. Carotid-femoral pulse-wave velocity was higher in participants with autosomal dominant polycystic kidney disease compared with healthy controls (650±131 versus 562±81 cm/s; P=0.007). Brachial artery flow-mediated dilation was 8.2%±5.8% in participants with autosomal dominant polycystic kidney disease and 10.8%±4.7% in controls (P=0.08). Among participants with autosomal dominant polycystic kidney disease, flow-mediated dilation increased from 7.7%±4.5% to 9.4%±5.2% with ascorbic acid, a difference of 1.72 (95% confidence interval, 0.80 to 2.63), whereas in control participants, flow-mediated dilation decreased nonsignificantly from 10.8%±4.7% to 10.6%±5.4%, a difference of −0.20 (95% confidence interval, −1.24 to 0.84; P interaction =0.02). Endothelial cell protein expression of NF-κB was greater in participants with autosomal dominant polycystic kidney disease (0.48±0.12 versus 0.41±0.10 [intensity versus human umbilical vein endothelial cell control]; P=0.03). However, circulating oxidative stress markers and bioactive lipid mediators did not significantly differ according to the autosomal dominant polycystic kidney disease diagnosis. Conclusions These results provide support for the hypothesis that vascular oxidative stress and inflammation develop with autosomal dominant polycystic kidney disease. Podcast This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2018_09_18_CJASNPodcast_18_10_.mp3

Acute kidney injury (AKI) is a systemic disease associated with widespread effects on distant organs, including the heart. Normal cardiac function is dependent on constant ATP generation, and the preferred method of energy production is via oxidative phosphorylation. Following direct ischemic cardiac injury, the cardiac metabolome is characterized by inadequate oxidative phosphorylation, increased oxidative stress, and increased alternate energy utilization. We assessed the impact of ischemic AKI on the metabolomics profile in the heart. Ischemic AKI was induced by 22 minutes of renal pedicle clamping, and 124 metabolites were measured in the heart at 4 hours, 24 hours, and 7 days post-procedure. Forty-one percent of measured metabolites were affected, with the most prominent changes observed 24 hours post-AKI. The post-AKI cardiac metabolome was characterized by amino acid depletion, increased oxidative stress, and evidence of alternative energy production, including a shift to anaerobic forms of energy production. These metabolomic effects were associated with significant cardiac ATP depletion and with echocardiographic evidence of diastolic dysfunction. In the kidney, metabolomics analysis revealed shifts suggestive of energy depletion and oxidative stress, which were reflected systemically in the plasma. This is the first study to examine the cardiac metabolome after AKI, and demonstrates that effects of ischemic AKI on the heart are akin to the effects of direct ischemic cardiac injury.

Background: Evidence suggests that the renin-angiotensin-aldosterone system (RAAS) interacts with the vitamin D-fibroblast growth factor 23-Klotho axis. We investigated whether circulating mineral metabolism markers modify outcomes in response to RAAS inhibition in subjects with advanced chronic kidney disease (CKD). Methods: In this retrospective cohort study, we analyzed the association of angiotensin-converting enzyme inhibitor (ACEI) and angiotensin receptor blocker (ARB) use with all-cause mortality and dialysis initiation among 1,753 subjects (1,099 CKD, estimated glomerular filtration rate 18 ± 6 ml/min/1.73 m2 and 654 end-stage renal disease [ESRD]) from the Homocysteine in Kidney and End Stage Renal Disease (HOST) study. A propensity score analysis accounted for indication bias and Cox regression models adjusted for mineral metabolism markers. Results: Mean follow-up was 3.2 years; 714 (41%) subjects died and 615 (56%) initiated dialysis. In adjusted analyses, all subjects treated with ACEI/ARB had a significantly lower hazard of death (hazards ratio (HR) 0.81, 95% CI 0.70-0.95, p = 0.007). Those with CKD not on dialysis and treated with ACEI/ARB trended toward a lower hazard of dialysis initiation (HR 0.86, 95% CI 0.73-1.01, p = 0.06). The association with mortality did not differ by level of mineral metabolism marker (p for interaction >0.16); however, the relationship with dialysis initiation differed according to the median serum phosphorus level (p for interaction Conclusions: RAAS inhibition was associated with decreased all-cause mortality independent of disordered mineral metabolism among mostly male HOST subjects with advanced CKD and ESRD. However, among those with CKD not requiring dialysis, the renoprotection associated with RAAS inhibition was attenuated by higher serum phosphorus levels. Further studies are needed to confirm this association.

In advanced renal disease, the kidney is unable to maintain phosphate balance due to decreased urinary excretion as well as the imbalance of the bone metabolic axis. It is well established that hyperphosphatemia is associated with increased cardiovascular events and mortality in patients with chronic kidney disease (CKD). However, there are no randomized controlled trials that demonstrate a clear benefit on hard outcomes in lowering serum phosphate levels to recommended targets in the CKD or dialysis population. In addition, while calcium-based phosphate binders have traditionally been the standard of care in the treatment of hyperphosphatemia, data regarding the increased risk of vascular mineralization continues to emerge. Clinicians continue to search for new phosphate-lowering therapies as well as investigate novel nutritional perspectives. The Kidney Disease: Improving Global Outcomes is currently revising the guidelines on phosphate goals in CKD. This review will outline the history of phosphate targets and phosphate binders, and explore innovative phosphate-lowering therapies. Based on current data, clinicians moving forward should continue to treat end-stage renal disease patients with hyperphosphatemia based on individual risk factors for vascular mineralization.

Abnormalities in phosphorus metabolism occur early in chronic kidney disease (CKD). Compensatory changes in renal phosphate handling are sufficient to maintain serum phosphorus within the normal laboratory range in early stages of kidney disease, but in more advanced kidney disease, these mechanisms no longer suffice and hyperphosphatemia ensues. Parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) are the main phosphaturic hormones that increase renal phosphate excretion by decreasing the renal sodium-phosphate cotransporters in the proximal tubule. FGF23 increases renal phosphate excretion earlier than PTH in response to abnormal phosphate homeostasis, and together elevations in FGF23 and PTH mediate processes that help restore serum phosphorus levels to normal in moderate-to-severe CKD. FGF23 is modulated by dietary phosphorus intake, 1,25-dihydroxyvitamin D (1,25(OH)2D), and PTH. FGF23 synthesis and release are positively regulated by serum phosphorus and 1,25(OH)2D and negatively regulated by unknown mechanisms. The major focus of this chapter will be to understand the mechanism of abnormal phosphorus homeostasis in patients with kidney disease, with particular attention to the biochemical/hormonal factors including vitamin D, PTH, and FGF23, as well as a brief consideration of bone and the intestine.

Cognitive impairment is common in advanced chronic kidney disease (CKD), but little is known about its relation with abnormalities in mineral metabolism. Methods: The longitudinal association between plasma 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), intact parathyroid hormone (iPTH), and fibroblast growth factor-23 (FGF-23) levels and cognitive function was assessed in 605 patients (67 ± 12 years) with advanced CKD not requiring dialysis (n = 247) or end-stage renal disease (ESRD; n = 358) who participated in the Homocysteine Study Cognitive Function Substudy (HOSTCOG)). Cognitive function was assessed using the Telephone Interview for Cognitive Status-modified (TICSm; mean follow-up 3.1 years) and associated with baseline mineral metabolite levels using linear regression analyses. Results: In unadjusted analyses, increasing log 1,25(OH)2D and decreasing log iPTH and FGF-23 levels were associated with worse cognitive status (p < 0.05). In fully adjusted multivariate analyses, the associations were no longer significant. Log 25(OH)D levels were not associated with cognitive function in unadjusted or adjusted analyses. Results were similar when analyzed by tertile or separately within CKD and ESRD groups. Conclusions: These results suggest that mineral metabolism dysregulation does not mediate the impairment in cognitive function common in advanced CKD.

Previous research has reported reduced serum 25-hydroxyvitamin D (25(OH)D) levels is associated with acute infectious illness. The relationship between vitamin D status, measured prior to acute infectious illness, with risk of community-acquired pneumonia (CAP) and sepsis has not been examined. Community-living individuals hospitalized with CAP or sepsis were age-, sex-, race-, and season-matched with controls. ICD-9 codes identified CAP and sepsis; chest radiograph confirmed CAP. Serum 25(OH)D levels were measured up to 15 months prior to hospitalization. Regression models adjusted for diabetes, renal disease, and peripheral vascular disease evaluated the association of 25(OH)D levels with CAP or sepsis risk. A total of 132 CAP patients and controls were 60 ± 17 years, 71% female, and 86% Caucasian. The 25(OH)D levels

In chronic kidney disease (CKD), high FGF23 concentrations are associated with left ventricular hypertrophy (LVH), cardiovascular events, and death. The associations of FGF23 with left ventricular mass (LVM) and LVH in the general population and the influence of CKD remains uncertain.C-terminal plasma FGF23 concentrations were measured, and LVM and LVH evaluated by echocardiogram among 2255 individuals ≥65 years in the Cardiovascular Health Study. Linear regression analysis adjusting for demographics, cardiovascular, and kidney related risk factors examined the associations of FGF23 concentrations with LVM. Analyses were stratified by CKD status and adjusted linear and logistic regression analysis explored the associations of FGF23 with LVM and LVH.Among the entire cohort, higher FGF23 concentrations were associated with greater LVM in adjusted analyses (β = 6.71 [95% CI 4.35-9.01] g per doubling of FGF23). 32% (n = 624) had CKD (eGFR60 mL/min/1.73 m(2) and/or urine albumin-to-creatinine ratio30 mg/g). Associations were stronger among participants with CKD (p interaction = 0.006): LVM β = 9.71 [95% CI 5.86-13.56] g per doubling of FGF23 compared to those without CKD (β = 3.44 [95% CI 0.77, 6.11] g per doubling of FGF23). While there was no significant interaction between FGF23 and CKD for LVH (p interaction = 0.25), the OR (1.46 95% CI [1.20-1.77]) in the CKD group was statistically significant and of larger magnitude than the OR for in the no CKD group (1.12 [95% CI 0.97-1.48]).In a large cohort of older community-dwelling adults, higher FGF23 concentrations were associated with greater LVM and LVH with stronger relationships in participants with CKD.

Context: Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone that also inhibits calcitriol synthesis. Objective: Our objective was to evaluate the relationships of plasma FGF23 concentrations with bone mineral density (BMD) and hip fracture in community-dwelling older adults. Design and Setting: Linear regression and Cox proportional hazard models were used to examine the associations of plasma FGF23 concentrations with BMD and incident hip fracture, respectively. Analyses were also stratified by chronic kidney disease. Participants: Participants included 2008 women and 1329 men ≥65 years from the 1996 to 1997 Cardiovascular Health Study visit. Main Outcome Measures: Dual x-ray absorptiometry measured total hip (TH) and lumbar spine (LS) BMD in 1291 participants. Hip fracture incidence was assessed prospectively through June 30, 2008 by hospitalization records in all participants. Results: Women had higher plasma FGF23 concentrations than men (75 [56–107] vs 66 [interquartile range = 52–92] relative units/mL; P < .001). After adjustment, higher FGF23 concentrations were associated with greater total hip and lumbar spine BMD in men only (β per doubling of FGF23 = 0.02, with 95% confidence interval [CI] = 0.001–0.04 g/cm2, and 0.03 with 95% CI = 0.01–0.06 g/cm2). During 9.6 ± 5.1–11.0 years of follow-up, 328 hip fractures occurred. Higher FGF23 concentrations were not associated with hip fracture risk in women or men (adjusted hazard ratio = 0.95, with 95% CI = 0.78–1.15, and 1.09 with 95% CI = 0.82–1.46 per doubling of FGF23). Results did not differ by chronic kidney disease status (P > .4 for interactions). Conclusions: In this large prospective cohort of community-dwelling older adults, higher FGF23 concentrations were weakly associated with greater lumbar spine and total hip BMD but not with hip fracture risk.

We sought to explore associations between serum 25-hydroxyvitamin D [25(OH)D] levels and non-alcoholic fatty liver disease [NAFLD] in an integrated healthcare delivery system in the U.S.Six hundred and seven NAFLD cases were randomly matched 1:1 with controls for age, sex, race and season of measurement. Conditional logistic regression was used to evaluate if serum 25(OH)D levels were associated with increased odds of NAFLD (diagnosed by ultrasound) after adjusting for body mass index and history of diabetes, renal, peripheral vascular and liver diseases (model 1) and also for hypertension (model 2). Mean (SD) serum 25(OH)D level was significantly lower in the group with NAFLD as compared with that in the matched control group (75 ± 17 vs. 85 ± 20 nmol/L [30 ± 7 vs. 34 ± 8 ng/mL], P0.001). Inadequate 25(OH)D status progressively increased the odds of NAFLD when classified categorically as sufficient (25(OH)D 75 nmol/L [30 ng/mL], reference group), insufficient (37-75 nmol/L [15-30 ng/mL]; adjusted odds ratio [OR]: 2.40, 95% confidence interval [CI]: 0.90-6.34) or deficient (37 nmol/L [15 ng/mL]; adjusted OR: 2.56, 95% CI: 1.27-5.19). When modeled as a continuous variable, increased log10 25(OH)D was inversely associated with the risk of prevalent NAFLD (adjusted OR: 0.25, 95% CI: 0.064-0.96, P=0.02).Compared with matched controls, patients with NAFLD have significantly decreased serum 25(OH)D levels, suggesting that low 25(OH)D status might play a role in the development and progression of NAFLD.

The treatment of hyponatremia, an exceedingly common electrolyte disorder, has been a subject of controversy for many years. The advent of vasopressin antagonists (vaptans) has added to the treatment arsenal. This review focuses on why hyponatremia should be treated and the role of these antagonists in the treatment. Upon analysis of the available literature, we conclude that there is presently no role for vaptans in acute symptomatic hyponatremia. Although numerous therapeutic approaches are available for chronic symptomatic hyponatremia, vasopressin antagonists provide a simpler treatment option. Vaptans are efficacious in raising serum sodium in long-standing ‘asymptomatic' hyponatremia. However, the cost of the only Food and Drug Administration-approved oral agent (tolvaptan) makes its use prohibitive for most patients in this setting.

Elevated levels of fibrobast growth factor 23 (FGF-23) are associated with cardiovascular and all-cause mortality in patients with kidney disease. A secondary analysis of the EVOLVE trial reports that cinacalcet-induced reductions in FGF-23 were associated with a reduced risk of cardiovascular events in patients with secondary hyperparathyroidism on dialysis.

Background There is a gap of knowledge in the long-term outcomes of patients who have complete recovery of kidney function after an episode of acute kidney injury (AKI). We sought to determine whether complete recovery of kidney function after an episode of AKI is associated with the development of incident stage 3 chronic kidney disease (CKD) and mortality in patients with normal baseline kidney function. Design Retrospective cohort study. Setting & Participants 3,809 patients from an integrated health care delivery system who had a hospitalization between January 1, 1999, and December 31, 2009, with follow-up through March 31, 2010. Predictor AKI defined by International Classification of Diseases, Ninth Revision ( ICD-9 ) codes and using the AKI Network (AKIN) definition, with complete recovery defined as a decrease in serum creatinine level to less than 1.10 times the baseline value. Outcomes and Measurements Incident stage 3 CKD persistent for 3 months and all-cause mortality. Results After a median follow-up of 2.5 years, incident stage 3 CKD occurred in 15% and 3% of those with and without AKI, respectively, with an unadjusted HR of 5.93 (95% CI, 4.49-7.84) and HR of 3.82 (95% CI, 2.81-5.19) in propensity score–stratified analyses. Deaths occurred in 35% and 24% of those with and without AKI, respectively, with an unadjusted HR of 1.46 (95% CI, 1.27-1.68). In propensity score–stratified analyses, HR decreased to 1.08 (95% CI, 0.93-1.27). Limitations Measurements of albuminuria were not available. Conclusions Complete recovery of kidney function after an episode of AKI in patients with normal baseline kidney function is associated with increased risk of the development of incident stage 3 CKD, but not all-cause mortality.

A consistent association between hyponatremia and increased mortality has been shown in hospitalized patients. A new study investigating dysnatremia in non-dialysis-dependent patients with chronic kidney disease found that both hyponatremia and hypernatremia are associated with increased mortality, independently of other diseases known to cause hyponatremia.

Summary Background and objectives This study examined differences in the concentration of markers of mineral metabolism across race in patients with advanced CKD not requiring dialysis and ESRD. Design, setting, participants, & measurements Concentrations of 25-hydroxyvitamin D (25(OH)D), 1,25dihydroxyvitamin D (1,25(OH)2D), intact parathyroid hormone (iPTH), and fibroblast growth factor 23 (FGF-23) were measured in stored plasmasamples of 1497 patients with advanced CKD not yet on dialysis and ESRD who participated in the Homocysteine in Kidney and End Stage Renal Disease study. Linear regression models were used to examine the relationship between race and 25(OH)D, 1,25(OH)2D, iPTH, and FGF-23 concentrations. ResultsNon-Hispanic white patients comprised 58% of the cohort, whereas non-Hispanic blacks comprised 42%. Median (interquartile range) FGF-23 concentrations were lower in blacks compared with whites with CKD (323 [181–655] versus 431 [232–1026] RU/ml; P,0.001) but not in ESRD. In adjusted linear regression models, blacks with CKD not requiring dialysis had significantly lower plasma FGF-23 concentrations (difference, 2159; 95% confidence interval, 2205 to 2106; P,0.001) compared with whites, independent of plasma 25(OH)D, 1,25(OH)2D, and iPTH concentrations. This difference was not observed in the ESRD group. The magnitude of correlation for the relationships between 1,25(OH)2D with iPTH, FGF-23 with 1,25(OH)2D, and FGF-23 with iPTH were stronger among blacks than whites with CKD not requiring dialysis. Conclusions In advanced CKD not requiring dialysis, blacks have lower FGF-23 concentrations than whites. Blacks with CKD and ESRD have lower 25(OH)D and higher iPTH compared with whites, independent of FGF-23 concentrations. Clin J Am Soc Nephrol 7: 640–647, 2012. doi: 10.2215/CJN.07020711