Head-to-head trial of pegunigalsidase alfa versus agalsidase beta in patients with Fabry disease and deteriorating renal function: results from the 2-year randomised phase III BALANCE study

BACKGROUND

Pegunigalsidase alfa is a PEGylated α-galactosidase A enzyme replacement therapy. BALANCE (NCT02795676) assessed non-inferiority of pegunigalsidase alfa versus agalsidase beta in adults with Fabry disease with an annualised estimated glomerular filtration rate (eGFR) slope more negative than -2 mL/min/1.73 m2/year who had received agalsidase beta for ≥1 year.

METHODS

Patients were randomly assigned 2:1 to receive 1 mg/kg pegunigalsidase alfa or agalsidase beta every 2 weeks for 2 years. The primary efficacy analysis assessed non-inferiority based on median annualised eGFR slope differences between treatment arms.

RESULTS

Seventy-seven patients received either pegunigalsidase alfa (n=52) or agalsidase beta (n=25). At baseline, mean (range) age was 44 (18-60) years, 47 (61%) patients were male, median eGFR was 74.5 mL/min/1.73 m2 and median (range) eGFR slope was -7.3 (-30.5, 6.3) mL/min/1.73 m2/year. At 2 years, the difference between median eGFR slopes was -0.36 mL/min/1.73 m2/year, meeting the prespecified non-inferiority margin. Minimal changes were observed in lyso-Gb3 concentrations in both treatment arms at 2 years. Proportions of patients experiencing treatment-related adverse events and mild or moderate infusion-related reactions were similar in both groups, yet exposure-adjusted rates were 3.6-fold and 7.8-fold higher, respectively, with agalsidase beta than pegunigalsidase alfa. At the end of the study, neutralising antibodies were detected in 7 out of 47 (15%) pegunigalsidase alfa-treated patients and 6 out of 23 (26%) agalsidase beta-treated patients. There were no deaths.

CONCLUSIONS

Based on rate of eGFR decline over 2 years, pegunigalsidase alfa was non-inferior to agalsidase beta. Pegunigalsidase alfa had lower rates of treatment-emergent adverse events and mild or moderate infusion-related reactions.

TRIAL REGISTRATION NUMBER

NCT02795676.

Risk Factors for Incident CKD in Black and White Americans: The REGARDS Study

RATIONALE & OBJECTIVE

Little information exists on the incidence of and risk factors for chronic kidney disease (CKD) in contemporary US cohorts and whether risk factors differ by race, sex, or region in the United States.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

4,198 Black and 7,799 White participants aged at least 45 years, recruited from 2003 through 2007 across the continental United States, with baseline estimated glomerular filtration rate (eGFR)>60mL/min/1.73m2 and eGFR assessed again approximately 9 years later.

EXPOSURES

Age, sex, race (Black or White), region ("stroke belt" or other), education, income, systolic blood pressure, body mass index, diabetes, coronary heart disease, hyperlipidemia, smoking, and albuminuria.

OUTCOMES

(1) eGFR change and (2) incident CKD defined as eGFR<60mL/min/1.73m2 and≥40% decrease from baseline or kidney failure.

ANALYTICAL APPROACH

Linear regression and modified Poisson regression were used to determine the association of risk factors with eGFR change and incident CKD overall and stratified by race, sex, and region.

RESULTS

Mean age of participants was 63±8 (SD) years, 54% were female, and 35% were Black. After 9.4±1.0 years of follow-up, CKD developed in 9%. In an age-, sex-, and race-adjusted model, Black race (β =-0.13; P<0.001) was associated with higher risk of eGFR change, but this was attenuated in the fully adjusted model (β=0.02; P=0.5). Stroke belt residence was independently associated with eGFR change (β =-0.10; P<0.001) and incident CKD (relative risk, 1.14 [95% CI, 1.01-1.30]). Albuminuria was more strongly associated with eGFR change (β of-0.26 vs-0.17; P=0.01 for interaction) in Black compared with White participants. Results were similar for incident CKD.

LIMITATIONS

Persons of Hispanic ethnicity were excluded; unknown duration and/or severity of risk factors.

CONCLUSIONS

Established CKD risk factors accounted for higher risk of incident CKD in Black versus White individuals. Albuminuria was a stronger risk factor for eGFR decrease and incident CKD in Black compared with White individuals. Living in the US stroke belt is a novel risk factor for CKD.

Elucidating the toxic effect and disease mechanisms associated with Lyso-Gb3 in Fabry disease

Fabry disease results from a deficiency of alpha-galactosidase and results in accumulation of Globotriaosylceramide (Gb3). However, the production of its deacylated form globotriaosylsphingosine (lyso-Gb3) is also observed and its plasma levels have closer association with disease severity. Studies have shown lyso-Gb3 directly affects podocytes and causes sensitisation of peripheral nociceptive neurons. However, little is understood of the mechanisms of this cytotoxicity. To study the effect on neuronal cells, we incubated SH-Sy5y cells with lyso-Gb3 at low (20 ng/mL) and high (200 ng/mL) levels, to mimic mild and classical FD serum levels. We used glucosylsphingosine as a positive control to determine specific effects of lyso-Gb3. Proteomic analyses revealed that cellular systems affected by lyso-Gb3 included cell signalling particularly protein ubiquitination and protein translation. To confirm ER/proteasome perturbations we performed an immune-enrichment of ubiquitinated proteins and demonstrated specific increased protein ubiquitination at both doses. The most ubiquitinated proteins observed included the chaperone/heat shock proteins, cytoskeletal proteins and synthesis/translation proteins. To detect proteins that interact directly with lyso-Gb3, we immobilised lyso-lipids, then incubated them with neuronal cellular extracts and identified bound proteins using mass spectrometry. Proteins that specifically bound were chaperones and included HSP90, HSP60 and the TRiC complex. In conclusion, lyso-Gb3 exposure affects pathways involved in protein translation and folding. This response is observed as increased ubiquitination and changes in signalling proteins which may explain the multiple biological processes, particularly cellular remodelling, often associated with FD.

7th Update on Fabry Disease: Biomarkers, Progression and Treatment Opportunities in 2022

no abstract.

Comparison of Static and Dynamic Baseline Creatinine Surrogates for Defining Acute Kidney Injury

BACKGROUND

"Dynamic" baseline serum creatinine (sCr), based on a rolling 48-h window, and a static baseline sCr (previous outpatient sCr) were used to define acute kidney injury (AKI).

METHODS

Retrospective cohort study of adult admissions to the University of Alabama (UAB) Health System hospitals for years 2016-2018. Included admissions had >1- and <180-day length of stay, >2 inpatient sCr measurements, and an averaged estimated glomerular filtration rate >15 mL/min/1.73 m2. The final cohort of 62,380 patients included 100,570 admissions, 3,509 inpatient deaths, and 1,916 admissions with inpatient dialysis. AKI was defined by Kidney Disease Improving Global Outcomes (KDIGO) criteria and a static or dynamic baseline sCr. Discrimination was evaluated with area under receiver operator curves (AUC), logistic regression, and net reclassification improvement (NRI).

RESULTS

Preadmission outpatient "static" sCr values were available for 43,433 admissions. The lowest sCr value during a rolling 48-h window before each inpatient sCr defined a "dynamic" baseline sCr. Using point-wise comparisons, the dynamic baseline sCr performed better than static baseline sCr for inpatient mortality (AUC [0.819 vs. 0.741; p < 0.001] and NRI ≥0.306 [p < 0.001]) and inpatient dialysis (AUC [0.903 vs. 0.864; p < 0.001] and NRI ≥0.317 [p < 0.001]).

CONCLUSIONS

The dynamic baseline sCr is available without reference to preadmission sCr values and avoids confounding associated with missing outpatient sCr values. AKI defined with the dynamic baseline sCr significantly improved discrimination of risk for inpatient mortality and dialysis compared to static baseline sCr.

Lyso-Gb3 associates with adverse long-term outcome in patients with Fabry disease

Background

Fabry disease (FD) is a rare X-linked lysosomal storage disease caused by mutations in the α-galactosidase A gene (GLA) leading to deficiency of α-galactosidase A and ultimately in progressive glycosphingolipid accumulation, especially globotriaosylceramide (Gb3) and its deacylated derivative globotriaosylsphingosine (Lyso-Gb3). The aim of the study was to assess plasma Lyso-Gb3 levels as a possible factor associated with adverse outcomes in FD.

Methods

In a cohort of 66 patients with genetically confirmed FD (26 males and 40 females), we analysed serum Lyso-Gb3 as a factor associated with adverse clinical outcomes in a long-term study. The main outcome was a composite endpoint of incident kidney replacement therapy, atrial fibrillation, pacemaker and/or implantable cardioverter defibrillator, cerebrovascular events or death, whichever occurred first.

Results

During the median follow-up time of 68 (40–80) months, events occurred in 19 (29%) of the patients. In a Cox multivariate regression analysis, Lyso-Gb3 levels (HR 4.62 (1.55 to 13.81); p=0.006) and the pretreatment exposure to Lyso-Gb3 (HR 3.41 (1.11 to 10.49); p=0.03) (both per SD increase) were significantly associated with adverse outcomes. If pretreatment Lyso-Gb3 exposure was added to multivariable logistic regression models containing age, sex, phenotype and enzyme replacement therapy as other covariates with the composite outcome as dependent variable, the area under the curve for the composite outcome significantly improved from 0.72 to 0.86 (p comparison=0.04).

Conclusion

Lyso-Gb3 is a significant risk factor associated with important clinical events. Whether treatment-related amelioration of Lyso-Gb3 levels will be associated with improved long-term outcome needs to be established in prospective intervention trials.

Early indicators of disease progression in Fabry disease that may indicate the need for disease-specific treatment initiation: findings from the opinion-based PREDICT-FD modified Delphi consensus initiative

OBJECTIVES

The PRoposing Early Disease Indicators for Clinical Tracking in Fabry Disease (PREDICT-FD) initiative aimed to reach consensus among a panel of global experts on early indicators of disease progression that may justify FD-specific treatment initiation.

DESIGN AND SETTING

Anonymous feedback from panellists via online questionnaires was analysed using a modified Delphi consensus technique. Questionnaires and data were managed by an independent administrator directed by two non-voting cochairs. First, possible early indicators of renal, cardiac and central/peripheral nervous system (CNS/PNS) damage, and other disease and patient-reported indicators assessable in routine clinical practice were compiled by the cochairs and administrator from panellists' free-text responses. Second, the panel scored indicators for importance (5-point scale: 1=not important; 5=extremely important); indicators scoring ≥3 among >75% of panellists were then rated for agreement (5-point scale: 1=strongly disagree; 5=strongly agree). Indicators awarded an agreement score ≥4 by >67% of panellists achieved consensus. Finally, any panel-proposed refinements to consensus indicator definitions were adopted if >75% of panellists agreed.

RESULTS

A panel of 21 expert clinicians from 15 countries provided information from which 83 possible current indicators of damage (kidney, 15; cardiac, 15; CNS/PNS, 13; other, 16; patient reported, 24) were compiled. Of 45 indicators meeting the importance criteria, consensus was reached for 29 and consolidated as 27 indicators (kidney, 6; cardiac, 10; CNS/PNS, 2; other, 6; patient reported, 3) including: (kidney) elevated albumin:creatinine ratio, histological damage, microalbuminuria; (cardiac) markers of early systolic/diastolic dysfunction, elevated serum cardiac troponin; (CNS/PNS) neuropathic pain, gastrointestinal symptoms suggestive of gastrointestinal neuropathy; (other) pain in extremities/neuropathy, angiokeratoma; (patient-reported) febrile crises, progression of symptoms/signs. Panellists revised and approved proposed chronologies of when the consensus indicators manifest. The panel response rate was >95% at all stages.

CONCLUSIONS

PREDICT-FD captured global opinion regarding current clinical indicators that could prompt FD-specific treatment initiation earlier than is currently practised.

Cardiovascular outcome trials in patients with chronic kidney disease: challenges associated with selection of patients and endpoints

Although cardiovascular disease is a major health burden for patients with chronic kidney disease, most cardiovascular outcome trials have excluded patients with advanced chronic kidney disease. Moreover, the major cardiovascular outcome trials that have been conducted in patients with end-stage renal disease have not demonstrated a treatment benefit. Thus, clinicians have limited evidence to guide the management of cardiovascular disease in patients with chronic kidney disease, particularly those on dialysis. Several factors contribute to both the paucity of trials and the apparent lack of observed treatment effect in completed studies. Challenges associated with conducting trials in this population include patient heterogeneity, complexity of renal pathophysiology and its interaction with cardiovascular disease, and competing risks for death. The Investigator Network Initiative Cardiovascular and Renal Clinical Trialists (INI-CRCT), an international organization of academic cardiovascular and renal clinical trialists, held a meeting of regulators and experts in nephrology, cardiology, and clinical trial methodology. The group identified several research priorities, summarized in this paper, that should be pursued to advance the field towards achieving improved cardiovascular outcomes for these patients. Cardiovascular and renal clinical trialists must partner to address the uncertainties in the field through collaborative research and design clinical trials that reflect the specific needs of the chronic and end-stage kidney disease populations, with the shared goal of generating robust evidence to guide the management of cardiovascular disease in patients with kidney disease.

Use of a rare disease registry for establishing phenotypic classification of previously unassigned GLA variants: a consensus classification system by a multispecialty Fabry disease genotype-phenotype workgroup

BACKGROUND

Fabry disease (α-galactosidase deficiency) is an X-linked genetic disease caused by a variety of pathogenic GLA variants. The phenotypic heterogeneity is considerable, with two major forms, classic and later-onset disease, but adjudication of clinical phenotype is currently lacking for many variants. We aimed to determine consensus phenotypic classification for previously unclassified GLA variants from the GLA-specific fabry-database.org database.

METHODS

A Fabry disease genotype-phenotype workgroup developed a five-stage iterative system based on expert clinical assessment, published literature and clinical evidence of pathogenicity using a 2-point scoring system based on clinical hallmarks of classic disease. Kaplan-Meier (KM) analysis of severe clinical event-free survival was used as final validation. Results were compared with those from web-based disease databases and in silico pathogenicity prediction programmes.

RESULTS

Final consensus on classifications of 'pathogenic' was achieved for 32 of 33 GLA variants (26 'classic' phenotype, 171 males; 6 'later-onset' phenotype, 57 males). One variant remained of uncertain significance. KM curves were similar for the known fabry-database.org database phenotypes and when workgroup consensus classifications were added, and the curves retained the same separation between 'classic' and 'later-onset' phenotypes.

CONCLUSION

The iterative system implemented by a Fabry disease genotype-phenotype workgroup achieved phenotypic classifications for variants that were previously unclassified. Clinical pathogenicity associated with a particular GLA variant defined in affected males appears to have predictive value and also generally correlates with risk for affected females. The newly established classifications can be of benefit to the clinical care of Fabry patients harbouring these variants.

Current and Investigational Therapeutics for Fabry Disease

Fabry disease (FD) is an X-linked lysosomal storage disease caused by a deficiency in the lysosomal enzyme α-galactosidase (α-GAL). This in turn leads to the buildup of globotriaosylceramide, resulting classically in progressive kidney disease, peripheral neuropathy, early-onset cerebrovascular disease, gastrointestinal symptoms, hypertrophic cardiomyopathy, arrhythmias, corneal whorls, and angiokeratomas. The diagnosis of FD relies on identification of a low α-GAL enzyme activity, identification of a genetic mutation, or histologic evidence of disease. With more than 900 mutations identified, there is phenotypic variability deriving from both mutational effects as well as the effect of skewed X-inactivation in females. Treatment of this disease has relied on intravenous replacement of the deficient enzyme with agalsidase α or agalsidase β. However, treatment options for some patients with FD have recently expanded, with the approval of migalastat, an oral molecular chaperone. In addition to chaperone-based therapies, there are several additional therapies under development that could substantially reshape treatment options for patients with FD. Four approaches to gene therapy, through both ex vivo and in vivo methods, are under development. Another approach is through the administration of α-GAL mRNA to help stimulate production of α-GAL, which is another unique form of therapy. Finally, substrate reduction therapies act as inhibitors of glucosylceramide synthase, thus inhibiting the production of GB-3, promise another oral option to treat FD. This article will review the literature around current therapies as well as these newer therapeutics agents in the pipeline for FD.

Rapid, proteomic urine assay for monitoring progressive organ disease in Fabry disease

BACKGROUND

Fabry disease is a progressive multisystemic disease, which affects the kidney and cardiovascular systems. Various treatments exist but decisions on how and when to treat are contentious. The current marker for monitoring treatment is plasma globotriaosylsphingosine (lyso-Gb3), but it is not informative about the underlying and developing disease pathology.

METHODS

We have created a urine proteomic assay containing a panel of biomarkers designed to measure disease-related pathology which include the inflammatory system, lysosome, heart, kidney, endothelium and cardiovascular system. Using a targeted proteomic-based approach, a series of 40 proteins for organ systems affected in Fabry disease were multiplexed into a single 10 min multiple reaction monitoring Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) assay and using only 1 mL of urine.

RESULTS

Six urinary proteins were elevated in the early-stage/asymptomatic Fabry group compared with controls including albumin, uromodulin, α1-antitrypsin, glycogen phosphorylase brain form, endothelial protein receptor C and intracellular adhesion molecule 1. Albumin demonstrated an increase in urine and could indicate presymptomatic disease. The only protein elevated in the early-stage/asymptomatic patients that continued to increase with progressive multiorgan involvement was glycogen phosphorylase brain form. Podocalyxin, fibroblast growth factor 23, cubulin and Alpha-1-Microglobulin/Bikunin Precursor (AMBP) were elevated only in disease groups involving kidney disease. Nephrin, a podocyte-specific protein, was elevated in all symptomatic groups. Prosaposin was increased in all symptomatic groups and showed greater specificity (p<0.025-0.0002) according to disease severity.

CONCLUSION

This work indicates that protein biomarkers could be helpful and used in conjunction with plasma lyso-Gb3 for monitoring of therapy or disease progression in patients with Fabry disease.

Effects of Bardoxolone Methyl on Magnesium in Patients with Type 2 Diabetes Mellitus and Chronic Kidney Disease

BACKGROUND

Treatment with bardoxolone methyl (Bard) in a multinational phase 3 trial, Bardoxolone Methyl Evaluation in Patients with Chronic Kidney Disease and Type 2 Diabetes (BEACON), resulted in increases in estimated glomerular filtration rate with concurrent reductions in serum magnesium. We analyzed data from several trials to characterize reductions in magnesium with Bard.

METHODS

BEACON randomized patients (n = 2,185) with type 2 diabetes (T2DM) and stage 4 chronic kidney disease (CKD) 1:1 to receive Bard (20 mg) or placebo once daily. In a separate open-label study, magnesium levels from 24-hour urine and sublingual epithelial cell samples were analyzed in patients with stage 3b-4 CKD and T2DM administered 20 mg Bard for 56 consecutive days.

RESULTS

BEACON patients randomized to Bard experienced significant reductions in serum magnesium from baseline relative to patients randomized to placebo (-0.17 mEq/L, 95% CI -0.18 to -0.60 mEq/L; p < 0.001). A separate study showed intracellular and urinary magnesium levels were unchanged with Bard treatment.

CONCLUSIONS

Bard treatment results in significant decreases in serum magnesium that are not associated with changes in intracellular and urinary magnesium levels, indicating that magnesium decreases are not due to renal magnesium wasting or total body magnesium depletion. Importantly, the decreases in serum magnesium with Bard are not associated with adverse effects on QT interval.

Serum albumin concentration and risk of end-stage renal disease: the REGARDS study

Background

Serum albumin concentration is a commonly available biomarker with prognostic value in many disease states. It is uncertain whether serum albumin concentrations are associated with incident end-stage renal disease (ESRD) independently of urine albumin-to-creatinine ratio (ACR).

Methods

A longitudinal evaluation was performed of a population-based community-living cohort from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study. Participants were ≥45 years of age at study entry and had serum albumin, creatinine, cystatin C and spot urine ACR measured at the baseline visit (n = 19 633). Estimated glomerular filtration rate (eGFR) was from the Chronic Kidney Disease Epidemiology Collaboration combined creatinine-cystatin C equation. Baseline serum albumin concentration was the predictor variable, and hazard ratios (HRs) for incident ESRD (from US Renal Data System linkage) were calculated in sequentially adjusted models.

Results

Age at study entry was 63.9 ± 9.7 years, 62% of the participants were female and 40% were black. Mean eGFR at baseline was 83.3 ± 20.8 mL/min/1.73 m2. Over a median 8-year follow-up, 1.2% (n = 236) developed ESRD. In models adjusted for baseline eGFR, ACR and other ESRD risk factors, the HR for incident ESRD was 1.16 [95% confidence interval (CI) 1.01-1.33] for each standard deviation (0.33 g/dL) lower serum albumin concentration. The HR comparing the lowest (<4 g/dL) and highest quartiles (≥4.4 g/dL) of serum albumin was 1.61 (95% CI 0.98-2.63). Results were qualitatively similar among participants with eGFR <60 and ≥60 mL/min/1.73 m2, and those with and without diabetes.

Conclusions

In community-dwelling US adults, lower serum albumin concentration is associated with higher risk of incident ESRD independently of baseline urine ACR, eGFR and other ESRD risk factors.

Urinary Tubular Injury Biomarkers Are Associated With ESRD and Death in the REGARDS Study

Introduction

Urinary neutrophil gelatinase-associated lipocalin (uNGAL) and urinary kidney injury molecule-1 (uKIM-1) are established markers of subclinical acute kidney injury. In persons with reduced estimated glomerular filtration rate (eGFR) and albuminuria who are at high risk for end-stage renal disease (ESRD) and death, the associations of these urinary markers with incident ESRD or death is an area of active investigation.

Methods

Among 1472 black and white participants from the REasons for Geographic and Racial Differences in Stroke (REGARDS) study with eGFR ≤60 ml/min per 1.73 m² (Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI] cystatin, 2012) and albumin-to-creatinine ratio (ACR) ≥30 mg/g, we evaluated the associations of baseline uNGAL and uKIM-1 with progression to ESRD and all-cause death. Cox models were sequentially adjusted for urinary creatinine, traditional risk factors, C-reactive protein, ACR, and eGFR.

Results

There were 257 ESRD events and 819 deaths over a median follow-up of 5.7 and 6.5 years, respectively. In demographic adjusted models, higher levels of uNGAL were associated with increased risk of ESRD and death, but these associations were attenuated in fully adjusted models including baseline eGFR for both ESRD (hazard ratio [HR] = 1.06 per doubling, 95% confidence interval [CI] 0.98-1.14) and death (HR = 1.04, 95% CI = 1.00-1.08). Higher levels of uKIM-1 were associated with increased risk of ESRD and death in demographic-adjusted models, and although attenuated in fully adjusted models, remained statistically significant for both ESRD (HR = 1.24 per doubling, 95% CI = 1.08-1.42) and death (HR = 1.10, 95% CI =1.03-1.19).

Conclusion

In this cohort of high-risk patients with baseline eGFR ≤60 ml/min per 1.73 m² and albuminuria, renal tubular injury is associated with higher mortality and progression to ESRD. Further studies are necessary to investigate the mechanism underlying this increased risk.

Dietary Oxidative Balance Scores and Biomarkers of Inflammation among Individuals with and without Chronic Kidney Disease

BACKGROUND

Oxidative stress and inflammation are proposed mechanisms of nonspecific kidney injury and progressive kidney failure. Higher dietary oxidative balance scores (OBS) are associated with lower prevalence of chronic kidney disease (CKD).

METHODS

We investigated the association between OBS and biomarkers of inflammation using data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study. Nutrient estimates from the Block Food Frequency Questionnaires were used to define tertiles of 11 pro- and antioxidant factors. Points for each OBS component were summed, with a higher score indicating predominance of antioxidant exposures. Multivariable linear regression models were used to estimate the association between OBS and biomarkers of inflammation (interleukin-6 [IL-6], interleukin-8 [IL-8], interleukin-10 [IL-10], fibrinogen, C-reactive protein [CRP], white blood cell count, and cystatin C). An interaction term was included to determine if associations between OBS and inflammatory markers differed between individuals with and without CKD.

RESULTS

Of 682 participants, 22.4% had CKD. In adjusted models, OBS was associated with CRP and IL-6. For every 5-unit increase in OBS, the CRP concentration was -15.3% lower (95% CI: -25.6, -3.6). The association of OBS with IL-6 differed by CKD status; for every 5-unit increase in OBS, IL-6 was -10.7% lower (95% CI: -16.3, -4.7) among those without CKD, but there was no association among those with CKD (p = 0.03).

CONCLUSION

This study suggests that a higher OBS is associated with more favorable levels of IL-6 and CRP, and that the association of OBS and IL-6 may be modified by CKD status.

Blood Pressure and Metabolic Effects of Acetyl-l-Carnitine in Type 2 Diabetes: DIABASI Randomized Controlled Trial

Context

Acetyl-l-carnitine (ALC), a mitochondrial carrier involved in lipid oxidation and glucose metabolism, decreased systolic blood pressure (SBP), and ameliorated insulin sensitivity in hypertensive nondiabetic subjects at high cardiovascular risk.

Objective

To assess the effects of ALC on SBP and glycemic and lipid control in patients with hypertension, type 2 diabetes mellitus (T2D), and dyslipidemia on background statin therapy.

Design

After 4-week run-in period and stratification according to previous statin therapy, patients were randomized to 6-month, double-blind treatment with ALC or placebo added-on simvastatin.

Setting

Five diabetology units and one clinical research center in Italy.

Patients

Two hundred twenty-nine patients with hypertension and dyslipidemic T2D >40 years with stable background antihypertensive, hypoglycemic, and statin therapy and serum creatinine <1.5 mg/dL.

Interventions

Oral ALC 1000 mg or placebo twice daily on top of stable simvastatin therapy.

Outcome and Measures

Primary outcome was SBP. Secondary outcomes included lipid and glycemic profiles. Total-body glucose disposal rate and glomerular filtration rate were measured in subgroups by hyperinsulinemic–euglycemic clamp and iohexol plasma clearance, respectively.

Results

SBP did not significantly change after 6-month treatment with ALC compared with placebo (−2.09 mm Hg vs −3.57 mm Hg, P = 0.9539). Serum cholesterol, triglycerides, and lipoprotein(a), as well as blood glucose, glycated hemoglobin, fasting insulin levels, homeostatic model assessment of insulin resistance index, glucose disposal rate, and glomerular filtration rate did not significantly differ between treatments. Adverse events were comparable between groups.

Conclusions

Six-month oral ALC supplementation did not affect blood pressure, lipid and glycemic control, insulin sensitivity and kidney function in hypertensive normoalbuminuric and microalbuminuric T2D patients on background statin therapy.

Bardoxolone Methyl Improves Kidney Function in Patients with Chronic Kidney Disease Stage 4 and Type 2 Diabetes: Post-Hoc Analyses from Bardoxolone Methyl Evaluation in Patients with Chronic Kidney Disease and Type 2 Diabetes Study

BACKGROUND

Increases in measured inulin clearance, measured creatinine clearance, and estimated glomerular filtration rate (eGFR) have been observed with bardoxolone methyl in 7 studies enrolling approximately 2,600 patients with type 2 diabetes (T2D) and chronic kidney disease (CKD). The largest of these studies was Bardoxolone Methyl Evaluation in Patients with Chronic Kidney Disease and Type 2 Diabetes (BEACON), a multinational, randomized, double-blind, placebo-controlled phase 3 trial which enrolled patients with T2D and CKD stage 4. The BEACON trial was terminated after preliminary analyses showed that patients randomized to bardoxolone methyl experienced significantly higher rates of heart failure events. We performed post-hoc analyses to characterize changes in kidney function induced by bardoxolone methyl.

METHODS

Patients in -BEACON (n = 2,185) were randomized 1: 1 to receive once-daily bardoxolone methyl (20 mg) or placebo. We compared the effects of bardoxolone methyl and placebo on a post-hoc composite renal endpoint consisting of ≥30% decline from baseline in eGFR, eGFR <15 mL/min/1.73 m2, and end-stage renal disease (ESRD) events (provision of dialysis or kidney transplantation).

RESULTS

Consistent with prior studies, patients randomized to bardoxolone methyl experienced mean increases in eGFR that were sustained through study week 48. Moreover, increases in eGFR from baseline were sustained 4 weeks after cessation of treatment. Patients randomized to bardoxolone methyl were significantly less likely to experience the composite renal endpoint (hazards ratio 0.48 [95% CI 0.36-0.64]; p < 0.0001).

CONCLUSIONS

Bardoxolone methyl preserves kidney function and may delay the onset of ESRD in patients with T2D and stage 4 CKD.

Improving Outcomes from Acute Kidney Injury (AKI): Report on an Initiative

Acute Kidney Injury (AKI) is a complex disorder for which currently there is no accepted definition. We describe an initiative to develop uniform standards for defining and classifying AKI and establish a forum for multidisciplinary interaction to improve care for patients with, or at risk for AKI. Members representing key societies in critical care and nephrology along with additional experts in adult and pediatric AKI participated in a 2-day conference in Amsterdam in September 2005 to draft consensus recommendations for diagnosing and staging AKI. This report describes the proposed diagnostic and staging criteria for AKI and the formation of a multidisciplinary collaborative network (Acute Kidney Injury Network (AKIN) focused on improving outcomes from AKI.

The pressing need for real-time risk assessment of hospital-acquired acute kidney injury

Acute Kidney Injury (AKI) is associated with short- and long-term outcomes that reflect the severity of the injury. Recent studies have suggested that 'early' initiation of renal replacement therapy may alter the course of AKI and improve short-term outcomes like inpatient mortality. The current Kidney Disease Improving Global Outcomes (KDIGO) consensus definition of AKI has been criticized for misclassification bias, lack of sensitivity and the static manner in which AKI stages are defined. This editorial reviews various approaches to improving the specificity and sensitivity of the KDIGO AKI criteria, and also concludes that a staging system based on creatinine trajectories would be better suited for developing a prognostic index for real-time, dynamic risk assessment that the current KDIGO staging criteria.

Allogeneic Mesenchymal Stem Cells for Treatment of AKI after Cardiac Surgery

AKI after cardiac surgery remains strongly associated with mortality and lacks effective treatment or prevention. Preclinical studies suggest that cell-based interventions may influence functional recovery. We conducted a phase 2, randomized, double-blind, placebo-controlled trial in 27 centers across North America to determine the safety and efficacy of allogeneic human mesenchymal stem cells (MSCs) in reducing the time to recovery from AKI after cardiac surgery. We randomized 156 adult subjects undergoing cardiac surgery with evidence of early AKI to receive intra-aortic MSCs (AC607; n=67) or placebo (n=68). The primary outcome was the time to recovery of kidney function defined as return of postintervention creatinine level to baseline. The median time to recovery of kidney function was 15 days with AC607 and 12 days with placebo (25th, 75th percentile range, 10-29 versus 6-21, respectively; hazard ratio, 0.81; 95% confidence interval, 0.53 to 1.24; P=0.32). We did not detect a significant difference between groups in 30-day all-cause mortality (16.7% with AC607; 11.8% with placebo) or dialysis (10.6% with AC607; 7.4% with placebo). At follow-up, 12 patients who received AC607 and six patients who received placebo had died. Rates of other adverse events did not differ between groups. In these patients with AKI after cardiac surgery, administration of allogeneic MSCs did not decrease the time to recovery of kidney function. Our results contrast with those in preclinical studies and provide important information regarding the potential effects of MSCs in this setting.

Conjunctival lymphangiectasia associated with classic Fabry disease

Background

Fabry disease (FD) is a treatable multisystem disease caused by a defect in the alpha-galactosidase gene. Ocular signs of FD, including corneal verticillata, are among the earliest diagnostic findings. Conjunctival lymphangiectasia (CL) has not previously been associated with FD.

Methods

We examined the eyes of a cohort of 13 adult patients, eight men and five women, with documented classic FD, all treated with enzyme replacement therapy (ERT) at the University of Alabama at Birmingham between February 2014 and April 2015. The average age was 48 years with a range of 35–55 years for men and 21–71 years for women. The mean duration of ERT was 8.4 years (men 8.9 years, women 7.6 years) with a range of 4–14 years. Classical Fabry mutations included Q283X, R227X, W236X and W277X. A high resolution Haag-Streit BQ-900 slit lamp with EyeCap imaging system was used to record conjunctival images.

Results

CL was observed in 11 of the 13 patients (85%) despite long-term ERT. Clinical presentations included single cysts, beaded dilatations and areas of conjunctival oedema. Lesions were located within 6 mm of the corneal limbus. Ten of the 13 subjects (77%) had Fabry-related cataracts and all 13 demonstrated bilateral corneal verticillata. Twelve of the 13 patients had evidence of dry eye, 9 of whom were symptomatic, and 10 had peripheral lymphoedema.

Conclusion

CL represents a common but under-recognised ocular manifestation of FD, which persists despite ERT, and is often accompanied by peripheral lymphoedema and dry eye syndrome.

Global Cardiovascular and Renal Outcomes of Reduced GFR

The burden of premature death and health loss from ESRD is well described. Less is known regarding the burden of cardiovascular disease attributable to reduced GFR. We estimated the prevalence of reduced GFR categories 3, 4, and 5 (not on RRT) for 188 countries at six time points from 1990 to 2013. Relative risks of cardiovascular outcomes by three categories of reduced GFR were calculated by pooled random effects meta-analysis. Results are presented as deaths for outcomes of cardiovascular disease and ESRD and as disability-adjusted life years for outcomes of cardiovascular disease, GFR categories 3, 4, and 5, and ESRD. In 2013, reduced GFR was associated with 4% of deaths worldwide, or 2.2 million deaths (95% uncertainty interval [95% UI], 2.0 to 2.4 million). More than half of these attributable deaths were cardiovascular deaths (1.2 million; 95% UI, 1.1 to 1.4 million), whereas 0.96 million (95% UI, 0.81 to 1.0 million) were ESRD-related deaths. Compared with metabolic risk factors, reduced GFR ranked below high systolic BP, high body mass index, and high fasting plasma glucose, and similarly with high total cholesterol as a risk factor for disability-adjusted life years in both developed and developing world regions. In conclusion, by 2013, cardiovascular deaths attributed to reduced GFR outnumbered ESRD deaths throughout the world. Studies are needed to evaluate the benefit of early detection of CKD and treatment to decrease these deaths.

Screening, diagnosis, and management of patients with Fabry disease: conclusions from a "Kidney Disease: Improving Global Outcomes" (KDIGO) Controversies Conference

Patients with Fabry disease (FD) are at a high risk for developing chronic kidney disease and cardiovascular disease. The availability of specific but costly therapy has elevated the profile of this rare condition. This KDIGO conference addressed controversial areas in the diagnosis, screening, and management of FD, and included enzyme replacement therapy and nonspecific standard-of-care therapy for the various manifestations of FD. Despite marked advances in patient care and improved overall outlook, there is a need to better understand the pathogenesis of this glycosphingolipidosis and to determine the appropriate age to initiate therapy in all types of patients. The need to develop more effective specific therapies was also emphasized.

Risk factors for severe clinical events in male and female patients with Fabry disease treated with agalsidase beta enzyme replacement therapy: Data from the Fabry Registry

BACKGROUND

Fabry disease, an X-linked lysosomal storage disorder, causes intracellular accumulation of glycosphingolipids leading to progressive renal, cardiovascular, and cerebrovascular disease, and premature death.

METHODS

This longitudinal Fabry Registry study analyzed data from patients with Fabry disease to determine the incidence and type of severe clinical events following initiation of enzyme replacement therapy (ERT) with agalsidase beta, as well as risk factors associated with occurrence of these events. Severe events assessed included chronic dialysis, renal transplantation, cardiac events, stroke, and death.

RESULTS

The analyses included 969 male and 442 female Fabry patients. The mean age at first agalsidase beta infusion was 35 and 44, and median treatment follow-up 4.3years and 3.2years, respectively. Among males, cardiac events were the most common on-ERT events, followed by renal, stroke, and non-cardiac death. Among females, cardiac events were also most common followed by stroke and renal events. Patients with on-ERT events had significantly more advanced cardiac and renal disease at baseline as compared with patients without on-ERT events. Severe events were also associated with older age at ERT initiation (males and females), a history of pre-ERT events (females; approaching statistical significance in males), and a higher urinary protein/creatinine ratio (females). Approximately 65% of patients with pre-ERT events did not experience subsequent on-ERT events. Of patients without pre-ERT events, most (84% of males, 92% of females) remained event-free.

CONCLUSIONS

Patients with on-ERT severe events had more advanced Fabry organ involvement at baseline than those without such events and patients who initiated ERT at a younger age had less residual risk of on-ERT events. The observed patterns of residual risk may aid clinicians in multidisciplinary monitoring of male and female patients with Fabry disease receiving ERT, and in determining the need for administration of adjunctive therapies.

Significant improvement in Fabry disease podocytopathy after 3 years of treatment with agalsidase beta

BACKGROUND

Fabry disease is an X-linked lysosomal disorder caused by decreased activity of α-galactosidase A (GLA). Consequent accumulation of globotriaosylceramide (GL-3) in lysosomes results in damage to a variety of organs, including the kidneys. Enzyme replacement therapy (ERT) is an effective treatment, but whether it should be started before organ damage is evident is a matter of debate.

CASE DIAGNOSIS/TREATMENT

A 10-year-old boy who complained of severe sole pain for 3 years had been misdiagnosed with juvenile idiopathic arthritis. Further investigations revealed decreased GLA activity and a M1T mutation in the GLA gene causing protein truncation, suggestive of Fabry disease. Despite normal renal function and urinalysis, renal biopsy showed abnormal structure, with marked accumulation of GL-3 in podocytes, partial effacement of foot processes and irregularly reduced expression of nephrin in the slit diaphragm. After 1 year of ERT with 1 mg/kg agalsidase beta once every 2 weeks, his pain had resolved with ERT combined with carbamazepine and pregabalin. After 3 years of the ERT, repeat biopsy showed little renal GL-3 deposition, resolution of foot process effacement, and a dramatic improvement in nephrin expression.

CONCLUSIONS

There may be a window of opportunity in which pain and renal injury can be addressed in the early stages of Fabry disease. Early initiation of ERT should therefore be considered for children with Fabry disease.

Past Decline Versus Current eGFR and Subsequent Mortality Risk

A single determination of eGFR associates with subsequent mortality risk. Prior decline in eGFR indicates loss of kidney function, but the relationship to mortality risk is uncertain. We conducted an individual-level meta-analysis of the risk of mortality associated with antecedent eGFR slope, adjusting for established risk factors, including last eGFR, among 1.2 million subjects from 12 CKD and 22 other cohorts within the CKD Prognosis Consortium. Over a 3-year antecedent period, 12% of participants in the CKD cohorts and 11% in the other cohorts had an eGFR slope <-5 ml/min per 1.73 m(2) per year, whereas 7% and 4% had a slope >5 ml/min per 1.73 m(2) per year, respectively. Compared with a slope of 0 ml/min per 1.73 m(2) per year, a slope of -6 ml/min per 1.73 m(2) per year associated with adjusted hazard ratios for all-cause mortality of 1.25 (95% confidence interval [95% CI], 1.09 to 1.44) among CKD cohorts and 1.15 (95% CI, 1.01 to 1.31) among other cohorts during a follow-up of 3.2 years. A slope of +6 ml/min per 1.73 m(2) per year also associated with higher all-cause mortality risk, with adjusted hazard ratios of 1.58 (95% CI, 1.29 to 1.95) among CKD cohorts and 1.43 (95% CI, 1.11 to 1.84) among other cohorts. Results were similar for cardiovascular and noncardiovascular causes of death and stronger for longer antecedent periods (3 versus <3 years). We conclude that prior decline or rise in eGFR associates with an increased risk of mortality, independent of current eGFR.

Serum Creatinine Trajectories for Community- versus Hospital-Acquired Acute Kidney Injury

BACKGROUND

Patterns of acute kidney injury (AKI) can be distinguished by the rate of changes in the serum creation concentrations during hospitalizations. We hypothesized that the timing and values of minimum and maximum serum creatinine (sCr) could be used to distinguish between transient hospital-associated AKI (THA-AKI) and hospital-acquired AKI (HA-AKI).

MATERIALS AND METHODS

We evaluated adults admitted to 2 regionally distinct academic medical centers. Peak sCr during the hospitalization was used to define AKI, using absolute changes and timing from the minimum sCr. sCr trajectories were derived based on the rate of change between the minimum and peak creatinine concentrations.

RESULTS

Peak creatinine followed the minimum creatinine for HA-AKI, while the peak creatinine preceded the minimum creatinine for THA-AKI. There were 82,403 patients included in the analyses, and 53,882 (65%) did not have AKI during the index hospitalization. There were 2,611 inpatient deaths; HA-AKI had a 4.8-fold increased risk relative to those without AKI (p < 0.01), and transient AKI had a 1.6-fold increased risk for inpatient mortality relative to inpatients without AKI (p < 0.01).

CONCLUSIONS

Patients with hospital-associated AKI are at an increased risk for inpatient mortality. Creatinine trajectories can be used to describe the rate of development as well as recovery from inpatient AKI. The 24- and 48-hour interval slopes may be early indicators of developing AKI. © 2016 S. Karger AG, Basel.

Association of Reduced eGFR and Albuminuria with Serious Fall Injuries among Older Adults

BACKGROUND AND OBJECTIVES

Falls are common and associated with adverse outcomes in patients on dialysis. Limited data are available in earlier stages of CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We analyzed data from 8744 Reasons for Geographic and Racial Differences in Stroke Study participants ≥65 years old with Medicare fee for service coverage. Serious fall injuries were defined as a fall-related fracture, brain injury, or joint dislocation using Medicare claims. Hazard ratios (HRs) for serious fall injuries were calculated by eGFR and albumin-to-creatinine ratio (ACR). Among 2590 participants with CKD (eGFR<60 ml/min per 1.73 m(2) or ACR≥30 mg/g), cumulative mortality after a serious fall injury compared with age-matched controls without a fall injury was calculated.

RESULTS

Overall, 1103 (12.6%) participants had a serious fall injury over 9.9 years of follow-up. The incidence rates per 1000 person-years of serious fall injuries were 21.7 (95% confidence interval [95% CI], 20.3 to 23.2), 26.6 (95% CI, 22.6 to 31.3), and 38.3 (95% CI, 31.2 to 47.0) at eGFR levels ≥60, 45-59, and <45 ml/min per 1.73 m(2), respectively, and 21.3 (95% CI, 20.0 to 22.8), 31.7 (95% CI, 27.5 to 36.5), and 42.2 (95% CI, 31.3 to 56.9) at ACR levels <30, 30-299, and ≥300 mg/g, respectively. Multivariable adjusted HRs for serious fall injuries were 0.91 (95% CI, 0.76 to 1.09) and 1.09 (95% CI, 0.86 to 1.37) for eGFR=45-59 and <45 ml/min per 1.73 m(2), respectively, versus eGFR≥60 ml/min per 1.73 m(2) and 1.31 (95% CI, 1.11 to 1.54) and 1.81 (95% CI, 1.30 to 2.50) for ACR=30-299 and ≥300 mg/g, respectively, versus ACR<30 mg/g. Among participants with CKD, cumulative 1-year mortality rates among patients with a serious fall and age-matched controls were 21.0% and 5.5%, respectively.

CONCLUSIONS

Elevated ACR but not lower eGFR was associated with serious fall injuries. Evaluation for fall risk factors and fall prevention strategies should be considered for older adults with elevated ACR.

Hemoglobin Concentration and Risk of Incident Stroke in Community-Living Adults

BACKGROUND AND PURPOSE

In previous observational studies, hemoglobin concentrations have been associated with an increased risk of stroke. However, these studies were limited by a relatively low number of stroke events, making it difficult to determine whether the association of hemoglobin and stroke differed by demographic or clinical factors.

METHODS

Using Cox proportional hazards analysis and Kaplan-Meier plots, we examined the association of baseline hemoglobin concentrations with incident stroke in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a cohort of black and white adults aged ≥45 years.

RESULTS

A total of 518 participants developed stroke over a mean 7±2 years of follow-up. There was a statistically significant interaction between hemoglobin and sex (P=0.05) on the risk of incident stroke. In Cox regression models adjusted for demographic and clinical variables, there was no association of baseline hemoglobin concentration with incident stroke in men, whereas in women, the lowest (<12.4 g/dL) and highest (>14.0 g/dL) quartiles of hemoglobin were associated with higher risk of stroke when compared with the second quartile (12.4-13.2 g/dL; quartile 1: hazard ratio, 1.59; 95% confidence interval, 1.09-2.31; quartile 2: referent; quartile 3: hazard ratio, 0.91; 95% confidence interval, 0.59-1.38; quartile 4: hazard ratio, 1.59; 95% confidence interval, 1.08-2.35). Similar results were observed in models stratified by hemoglobin and sex and when hemoglobin was modeled as a continuous variable using restricted quadratic spline regression.

CONCLUSIONS

Lower and higher hemoglobin concentrations were associated with a higher risk of incident stroke in women. No such associations were found in men.

Time to treatment benefit for adult patients with Fabry disease receiving agalsidase β: data from the Fabry Registry

Background

Agalsidase β is a form of enzyme replacement therapy for Fabry disease, a genetic disorder characterised by low α-galactosidase A activity, accumulation of glycosphingolipids and life-threatening cardiovascular, renal and cerebrovascular events. In clinical trials, agalsidase β cleared glycolipid deposits from endothelial cells within 6 months; clearance from other cell types required sustained treatment. We hypothesised that there might be a ‘lag time’ to clinical benefit after initiating agalsidase β treatment, and analysed the incidence of severe clinical events over time in patients receiving agalsidase β.

Methods

The incidence of severe clinical events (renal failure, cardiac events, stroke, death) was studied in 1044 adult patients (641 men, 403 women) enrolled in the Fabry Registry who received agalsidase β (average dose 1 mg/kg every 2 weeks) for up to 5 years.

Results

The incidence of all severe clinical events was 111 per 1000 person-years (95% CI 84 to 145) during the first 6 months. After 6 months, the incidence decreased and remained stable within the range of 40–58 events per 1000 patient-years. The largest decrease in incidence rates was among male patients and those aged ≥40 years when agalsidase β was initiated.

Conclusions

Contrary to the expected increased incidence of severe clinical events with time, adult patients with Fabry disease had decreased incidence of severe clinical events after 6 months treatment with agalsidase β 1 mg/kg every 2 weeks.

Trial registration number

NCT00196742.

Estimated Glomerular Filtration Rate: Fit for What Purpose?

There is important nosologic utility in staging chronic kidney disease (CKD) based on estimates of glomerular filtration rate (GFR). These equations have been optimized for estimating GFR at a single point in time. Risk assessment models used for prognosis of specified outcome events have commonly incorporated estimated GFR (eGFR), but the validity of this approach has not been evaluated. The current objective is to evaluate the risk of all-cause mortality over a 10-year follow-up period with multivariable-adjusted Cox regression analysis, comparing CKD stages based on eGFR to Cockcroft-Gault estimated creatinine clearance (eCrCl). There were significant differences between Stage 3A and Stage 3B-5 hazard ratios for all-cause mortality (p = 0.003) using eCrCl categories, but not for the same eGFR categories (p = 0.241). Discrimination analysis showed that a clinically significant difference (relative integrated discrimination improvement 778.6%; p = 0.001) was observed between the 2 models for the age strata ≤64. While eGFR is more precise and accurate than the Cockcroft Gault equation for estimating measured GFR at a single point in time, eGFR does not perform as well as eCrCl for assessing risk of all-cause mortality over 10-year follow-up intervals.

The role of cystatin-C in the confirmation of reduced glomerular filtration rate among the oldest old

INTRODUCTION

Current guidelines suggest using cystatin-C to confirm a reduced creatinine-based estimated glomerular filtration rate (eGFRcr) when the latter is thought to be inaccurate. Older adults have reduced muscle mass, which may affect the accuracy of eGFRcr. We evaluated the use of cystatin-C-based eGFR (eGFRcys) to confirm reduced eGFRcr among adults ≥ 80 years of age and, for comparison, younger adults.

MATERIAL AND METHODS

We analyzed data from 3,059 REasons for Geographic And Racial Differences in Stroke (REGARDS) study participants with reduced eGFRcr (< 60 ml/min/1.73 m(2)) enrolled in 2003-2007 who were not on dialysis. eGFRcr and eGFRcys were calculated using age, sex and race-adjusted equations. Confirmed reduced eGFRcr was defined as eGFRcys < 60 ml/min/1.73 m(2). Prevalence of chronic kidney disease complications at baseline and all-cause mortality up to March 2012 were calculated. Analyses were stratified by age: < 65, 65-79 and ≥ 80 years.

RESULTS

Among participants < 65, 65-79 and ≥ 80 years of age, 76.5%, 85.7% and 92.5%, respectively, had reduced eGFRcr confirmed with eGFRcys (p < 0.001). Among participants ≥ 80 years of age, those with reduced eGFRcr confirmed with eGFRcys had higher prevalence of hypertension (79.1% vs. 65.1%, p = 0.03) and albuminuria (38.3% vs. 22.7%, p = 0.04) and higher risk for all-cause mortality (hazard ratio: 2.43; 95% confidence interval: 1.19-5.01) as compared with those in whom reduced eGFRcr was not confirmed by eGFRcys.

CONCLUSIONS

Reduced eGFRcr was confirmed using eGFRcys for the vast majority of adults ≥ 80 years. These results suggest that using cystatin-C to confirm a reduced eGFRcr may not be necessary among the oldest old.

Waist Circumference, Body Mass Index, and ESRD in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study

BACKGROUND

The association between waist circumference and end-stage renal disease (ESRD) remains poorly explored.

STUDY DESIGN

Longitudinal population-based cohort.

SETTING & PARTICIPANTS

Participants in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study (n=30,239) with information for body mass index (BMI), waist circumference, spot urine albumin-creatinine ratio (ACR), and estimated glomerular filtration rate (eGFR; n=26,960).

PREDICTOR

Elevated waist circumference or BMI.

OUTCOMES & MEASUREMENTS

Incident cases of ESRD were identified through linkage of REGARDS participants with the US Renal Data System.

RESULTS

Mean baseline age was 64.8 years, 45.8% were men, and 40.3% were black. Overall, 297 (1.1%) individuals developed ESRD during a median of 6.3 years. After adjustment for all covariates including waist circumference, no significant association was noted between BMI categories and ESRD incidence compared to BMI of 18.5 to 24.9 kg/m2 (referent). Higher waist circumference categories showed significantly increased hazard rates of ESRD, with waist circumference ≥ 108 cm in women and ≥122 cm in men (highest category) showing a 3.97-fold higher hazard rate (95% CI, 2.10-6.86) for ESRD compared to waist circumference < 80 cm in women and <94 cm in men (referent) after adjusting for demographic factors and BMI. However, no significant association was noted between any waist circumference category and ESRD incidence after adjustment for obesity-associated comorbid conditions and baseline ACR and eGFR.

LIMITATIONS

Short follow-up period (6.3 years) to assess ESRD risk among adults with eGFRs>60 mL/min/1.73 m2.

CONCLUSIONS

In this cohort of older adults, obesity as measured by waist circumference is associated with higher ESRD risk even with adjustment for BMI, whereas obesity as measured by BMI is not associated with higher ESRD risk after adjustment for waist circumference. However, no significant association is noted between increased waist circumference and ESRD risk after adjustment for obesity-related comorbid conditions, eGFR, and ACR.

Categories of Hospital-Associated Acute Kidney Injury: Time Course of Changes in Serum Creatinine Values

Hospital-associated acute kidney injury (HA-AKI) is associated with increased inpatient mortality. Our objective was to categorize HA-AKI based on the timing of minimum and peak inpatient serum creatinine (sCr) and describe the association with inpatient mortality.

MATERIALS AND METHODS

This study is a retrospective analysis of an administrative data set for adults admitted to a single medical center for over 4 years. Changes and timing of the minimum and peak sCr were used to define HA-AKI categories.

RESULTS

Peak creatinine followed minimum creatinine for HA-AKI, and preceded the minimum value for transient HA-AKI (THA-AKI). A subset of patients developed HA-AKI after recovering from THA-AKI. Multivariable Cox regression analyses examined the association between these categories and 28-day inpatient mortality, adjusting for age, sex, race, Charlson comorbidity index, baseline kidney function, AKI recovery and renal replacement therapy. There were 50,601 patients included in the analyses, and 29,996 (59%) did not have AKI. There were 2,440 deaths; HA-AKI had a 2.24-fold (95% CI 1.99-2.51) increased risk, while THA-AKI group (12,101) had a 1.23-fold (95% CI 1.09-1.40) increased risk for inpatient mortality. THA-AKI patients who recovered and then developed HA-AKI had the same mortality risk as THA-AKI (1.27-fold [95% CI 1.07-1.51]) but longer hospitalization and less recovery from AKI.

CONCLUSIONS

Risk of short-term inpatient mortality is associated with AKI, and this risk is attenuated with recovery of kidney function in the hospital. Systematic surveillance with repeated inpatient sCr values is needed to assess the short- and long-term consequences of HA-AKI.

Validation of an Albuminuria Self-assessment Tool in the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

We previously developed an 8-item self-assessment tool to identify individuals with a high probability of having albuminuria. This tool was developed and externally validated among non-Hispanic Whites and non-Hispanic Blacks. We sought to validate it in a multi-ethnic cohort that also included Hispanics and Chinese Americans.

DESIGN

This is a cross-sectional study.

SETTING

Data were collected using standardized questionnaires and spot urine samples at a baseline examination in 2000-2002. The 8 items in the self-assessment tool include age, race, gender, current cigarette smoking, history of diabetes, hypertension, or stroke, and self-rated health.

PARTICIPANTS

Of 6,814 community-dwelling adults aged 45-84 years participating in the Multi-Ethnic Study of Atherosclerosis (MESA), 6,542 were included in the primary analysis.

MAIN OUTCOME MEASURES

Albuminuria was defined as urine albumin-to-creatinine ratio ≥ 30 mg/g at baseline.

RESULTS

Among non-Hispanic Whites, non-Hispanic Blacks, Hispanics, and Chinese Americans, the prevalence of albuminuria was 6.0%, 11.3%, 11.6%, and 10.8%, respectively. The c-statistic for discriminating participants with and without albuminuria was .731 (95% CI: .692, .771), .728 (95% CI: .687, .761), .747 (95% CI: .709, .784), and .761 (95% CI: .699, .814) for non-Hispanic Whites, non-Hispanic Blacks, Hispanics, and Chinese Americans, respectively. The self-assessment tool over-estimated the probability of albuminuria for non-Hispanic Whites and Blacks, but was well-calibrated for Hispanics and Chinese Americans.

CONCLUSIONS

The albuminuria self-assessment tool maintained good test characteristics in this large multi-ethnic cohort, suggesting it may be helpful for increasing awareness of albuminuria in an ethnically diverse population.

Antiproteinuric therapy and Fabry nephropathy: factors associated with preserved kidney function during agalsidase-beta therapy

Background

Nephropathy is an important feature of classical Fabry disease, which results in alpha-galactosidase A deficiency and cellular globotriaosylceramide accumulation. We report the safety and efficacy of antiproteinuric therapy with ACE inhibitors or angiotensin II receptor blockers (ARBs) in a study of classical Fabry patients receiving recombinant agalsidase-beta therapy.

Methods and design

The goal was maintenance of urine protein to creatinine ratio (UPCR) <0.5 g/g or a 50% reduction in baseline UPCR for 24 patients at eight study sites. The change in estimated glomerular filtration rate (eGFR) was assessed over 21 months of treatment.

Results

18 out of 24 patients achieved the UPCR goal with eGFR slopes that were significantly better than six patients who did not achieve the UPCR goal (−3.6 (−4.8 to −1.1) versus −7.0 (−9.0 to −5.6) mL/min/1.73 m²/year, respectively, p=0.018). Despite achieving the UPCR goal, 67% (12/18 patients) still progressed with an eGFR slope <−2 mL/min/1.73 m²/year. Regression analysis showed that increased age at initiation of agalsidase-beta therapy was significantly associated with worsened kidney outcome. Hypotension and hyperkalaemia occurred in seven and eight patients, respectively, which required modification of antiproteinuric therapy but was not associated with serious adverse events.

Conclusions

This study documents the effectiveness of agalsidase-beta (1 mg/kg/2 weeks) and antiproteinuric therapy with ACE inhibitors and/or ARB in patients with severe Fabry nephropathy. Patients had preservation of kidney function if agalsidase-beta treatment was initiated at a younger age, and UPCR maintained at or below 0.5 g/g with antiproteinuric therapy.

Trial registration number

NCT00446862.

Sulfenic Acid Modification of Endothelin B Receptor is Responsible for the Benefit of a Nonsteroidal Mineralocorticoid Receptor Antagonist in Renal Ischemia

AKI is associated with high mortality rates and the development of CKD. Ischemia/reperfusion (IR) is an important cause of AKI. Unfortunately, there is no available pharmacologic approach to prevent or limit renal IR injury in common clinical practice. Renal IR is characterized by diminished nitric oxide bioavailability and reduced renal blood flow; however, the mechanisms leading to these alterations are poorly understood. In a rat model of renal IR, we investigated whether the administration of the novel nonsteroidal mineralocorticoid receptor (MR) antagonist BR-4628 can prevent or treat the renal dysfunction and tubular injury induced by IR. Renal injury induced by ischemia was associated with increased oxidant damage, which led to a cysteine sulfenic acid modification in endothelin B receptor and consequently decreased endothelial nitric oxide synthase activation. These modifications were efficiently prevented by nonsteroidal MR antagonism. Furthermore, we demonstrated that the protective effect of BR-4628 against IR was lost when a selective endothelin B receptor antagonist was coadministered. These data describe a new mechanism for reduced endothelial nitric oxide synthase activation during renal IR that can be blocked by MR antagonism with BR-4628.

Estimated glomerular filtration rate and albuminuria for prediction of cardiovascular outcomes: a collaborative meta-analysis of individual participant data

BACKGROUND

The usefulness of estimated glomerular filtration rate (eGFR) and albuminuria for prediction of cardiovascular outcomes is controversial. We aimed to assess the addition of creatinine-based eGFR and albuminuria to traditional risk factors for prediction of cardiovascular risk with a meta-analytic approach.

METHODS

We meta-analysed individual-level data for 637 315 individuals without a history of cardiovascular disease from 24 cohorts (median follow-up 4·2-19·0 years) included in the Chronic Kidney Disease Prognosis Consortium. We assessed C statistic difference and reclassification improvement for cardiovascular mortality and fatal and non-fatal cases of coronary heart disease, stroke, and heart failure in a 5 year timeframe, contrasting prediction models for traditional risk factors with and without creatinine-based eGFR, albuminuria (either albumin-to-creatinine ratio [ACR] or semi-quantitative dipstick proteinuria), or both.

FINDINGS

The addition of eGFR and ACR significantly improved the discrimination of cardiovascular outcomes beyond traditional risk factors in general populations, but the improvement was greater with ACR than with eGFR, and more evident for cardiovascular mortality (C statistic difference 0·0139 [95% CI 0·0105-0·0174] for ACR and 0·0065 [0·0042-0·0088] for eGFR) and heart failure (0·0196 [0·0108-0·0284] and 0·0109 [0·0059-0·0159]) than for coronary disease (0·0048 [0·0029-0·0067] and 0·0036 [0·0019-0·0054]) and stroke (0·0105 [0·0058-0·0151] and 0·0036 [0·0004-0·0069]). Dipstick proteinuria showed smaller improvement than ACR. The discrimination improvement with eGFR or ACR was especially evident in individuals with diabetes or hypertension, but remained significant with ACR for cardiovascular mortality and heart failure in those without either of these disorders. In individuals with chronic kidney disease, the combination of eGFR and ACR for risk discrimination outperformed most single traditional predictors; the C statistic for cardiovascular mortality fell by 0·0227 (0·0158-0·0296) after omission of eGFR and ACR compared with less than 0·007 for any single modifiable traditional predictor.

INTERPRETATION

Creatinine-based eGFR and albuminuria should be taken into account for cardiovascular prediction, especially when these measures are already assessed for clinical purpose or if cardiovascular mortality and heart failure are outcomes of interest. ACR could have particularly broad implications for cardiovascular prediction. In populations with chronic kidney disease, the simultaneous assessment of eGFR and ACR could facilitate improved classification of cardiovascular risk, supporting current guidelines for chronic kidney disease. Our results lend some support to also incorporating eGFR and ACR into assessments of cardiovascular risk in the general population.

FUNDING

US National Kidney Foundation, National Institute of Diabetes and Digestive and Kidney Diseases.

Rapid Immunochromatographic Detection of Serum Anti-α-Galactosidase A Antibodies in Fabry Patients after Enzyme Replacement Therapy

We developed an immunochromatography-based assay for detecting antibodies against recombinant α-galactosidase A proteins in serum. The evaluation of 29 serum samples from Fabry patients, who had received enzyme replacement therapy with agalsidase alpha and/or agalsidase beta, was performed by means of this assay method, and the results clearly revealed that the patients exhibited the same level of antibodies against both agalsidase alpha and agalsidase beta, regardless of the species of recombinant α-galactosidase A used for enzyme replacement therapy. A conventional enzyme-linked immunosorbent assay supported the results. Considering these, enzyme replacement therapy with agalsidase alpha or agalsidase beta would generate antibodies against the common epitopes in both agalsidase alpha and agalsidase beta. Most of the patients who showed immunopositive reaction exhibited classic Fabry phenotype and harbored gene mutations affecting biosynthesis of α-galactosidase A. As immunochromatography is a handy and simple assay system which can be available at bedside, this assay method would be extremely useful for quick evaluation or first screening of serum antibodies against agalsidase alpha or agalsidase beta in Fabry disease with enzyme replacement therapy.

Similar names for similar biologics

Approval of the first biosimilar in the USA may occur by the end of 2014, yet a naming approach for biosimilars has not been determined. Biosimilars are highly similar to their biologic reference product but are not identical to it, because of their structural complexity and variations in manufacturing processes among companies. There is a need for a naming approach that can distinguish a biosimilar from its reference product and other biosimilars and ensure accurate tracing of adverse events (AEs) to the administered product. In contrast, generic small-molecule drugs are identical to their reference product and, therefore, share the same nonproprietary name. Clinical trials required to demonstrate biosimilarity for approval may not detect rare AEs or those occurring after prolonged use, and the incidence of such events may differ between a biosimilar and its reference product. The need for precise biologic identification is further underscored by the possibility of biosimilar interchangeability, a US designation that will allow substitution without prescriber intervention. For several biologics, the US Food and Drug Administration (FDA) has used a naming approach that adds a prefix to a common root nonproprietary name, enabling healthcare providers to distinguish between products, avoid medication errors, and facilitate pharmacovigilance. We recommend that the FDA implement a biosimilars naming policy that likewise would add a distinguishable prefix or suffix to the root nonproprietary name of the reference product. This approach would ensure that a biosimilar could be distinguished from its reference product and other biosimilars in patient records and pharmacovigilance databases/reports, facilitating accurate attribution of AEs.

A Meta-analysis of the Association of Estimated GFR, Albuminuria, Diabetes Mellitus, and Hypertension With Acute Kidney Injury

BACKGROUND

Diabetes mellitus and hypertension are risk factors for acute kidney injury (AKI). Whether estimated glomerular filtration rate (eGFR) and urine albumin-creatinine ratio (ACR) remain risk factors for AKI in the presence and absence of these conditions is uncertain.

STUDY DESIGN

Meta-analysis of cohort studies.

SETTING & POPULATION

8 general-population (1,285,045 participants) and 5 chronic kidney disease (CKD; 79,519 participants) cohorts.

SELECTION CRITERIA FOR STUDIES

Cohorts participating in the CKD Prognosis Consortium.

PREDICTORS

Diabetes and hypertension status, eGFR by the 2009 CKD Epidemiology Collaboration creatinine equation, urine ACR, and interactions.

OUTCOME

Hospitalization with AKI, using Cox proportional hazards models to estimate HRs of AKI and random-effects meta-analysis to pool results.

RESULTS

During a mean follow-up of 4 years, there were 16,480 episodes of AKI in the general-population and 2,087 episodes in the CKD cohorts. Low eGFRs and high ACRs were associated with higher risks of AKI in individuals with or without diabetes and with or without hypertension. When compared to a common reference of eGFR of 80mL/min/1.73m(2) in nondiabetic patients, HRs for AKI were generally higher in diabetic patients at any level of eGFR. The same was true for diabetic patients at all levels of ACR compared with nondiabetic patients. The risk gradient for AKI with lower eGFRs was greater in those without diabetes than with diabetes, but similar with higher ACRs in those without versus with diabetes. Those with hypertension had a higher risk of AKI at eGFRs>60mL/min/1.73m(2) than those without hypertension. However, risk gradients for AKI with both lower eGFRs and higher ACRs were greater for those without than with hypertension.

LIMITATIONS

AKI identified by diagnostic code.

CONCLUSIONS

Lower eGFRs and higher ACRs are associated with higher risks of AKI among individuals with or without either diabetes or hypertension.