Quantifying the integrated physiological effects of endothelin-1 on cardiovascular and renal function in healthy subjects: a mathematical modeling analysis.

Endothelin-1 (ET-1) is a potent vasoconstrictor with strong anti-natriuretic and anti-diuretic effects. While many experimental studies have elucidated the mechanisms of ET-1 through its two receptors, ETA and ETB, the complexity of responses and sometimes conflicting data make it challenging to understand the effects of ET-1, as well as potential therapeutic antagonism of ET-1 receptors, on human physiology. In this study, we aimed to develop an integrated and quantitative description of ET-1 effects on cardiovascular and renal function in healthy humans by coupling existing experimental data with a mathematical model of ET-1 kinetics and an existing mathematical model of cardiorenal function. Using a novel agnostic and iterative approach to incorporating and testing potential mechanisms, we identified a minimal set of physiological actions of endothelin-1 through ETA and ETB receptors by fitting the physiological responses (changes in blood pressure, renal blood flow, glomerular filtration rate (GFR), and sodium/water excretion) to ET-1 infusion, with and without ETA/ETB antagonism. The identified mechanisms align with previous experimental studies on ET-1 and offer novel insights into the relative magnitude and significance of endothelin's effects. This model serves as a foundation for further investigating the mechanisms of ET-1 and its antagonists.

Insulin resistance, kidney outcomes and effects of the endothelin receptor antagonist atrasentan in patients with type 2 diabetes and chronic kidney disease.

BACKGROUND: Insulin resistance (IR) is a pathophysiologic hallmark of type 2 diabetes and associated with the presence of chronic kidney disease (CKD). Experimental studies suggest that endothelin-1 increases IR. We assessed the association between IR and cardio-renal outcomes and the effect of the selective endothelin receptor antagonist atrasentan on IR in patients with type 2 diabetes and CKD. METHODS: We used data from the RADAR and SONAR trials that recruited participants with type 2 diabetes and CKD [eGFR 25-75 mL/min/1.73 m², urine albumin-to-creatinine ratio of 300-5000 mg/g]. IR was calculated using the homeostatic model assessment (HOMA-IR). The association between HOMA-IR and the pre-specified cardio-renal outcomes was assessed using multivariable Cox proportional hazards regression, and effects of atrasentan on HOMA-IR by a linear mixed effect model. RESULTS: In the SONAR trial, each log-unit increase in HOMA-IR was associated with an increased risk of the composite cardio-renal outcome [hazard ratio 1.32 (95%CI 1.09,1.60; p = 0.004)], kidney outcome [hazard ratio 1.30 (95%CI 1.00,1.68; p-value = 0.048)], and the kidney or all-cause mortality outcome [hazard ratio 1.25 (95%CI 1.01,1.55; p-value = 0.037)]. After 12 weeks treatment in the RADAR trial (N = 123), atrasentan 0.75 mg/day and 1.25 mg/day compared to placebo reduced HOMA-IR by 19.1 (95%CI -17.4, 44.3) and 26.7% (95%CI -6.4, 49.5), respectively. In the SONAR trial (N = 1914), atrasentan 0.75 mg/day compared to placebo reduced HOMA-IR by 9.6% (95%CI 0.6, 17.9). CONCLUSIONS: More severe IR is associated with increased risk of cardio-renal outcomes. The endothelin receptor antagonist atrasentan reduced IR. TRIAL REGISTRATION: RADAR trial (Reducing Residual Albuminuria in Subjects With Diabetes and Nephropathy With AtRasentan): NCT01356849. SONAR trial (The Study Of Diabetic Nephropathy With AtRasentan) NCT01858532.

Cardiorenal protective effects of canagliflozin in CREDENCE according to glucose lowering.

INTRODUCTION: Relationships between glycemic-lowering effects of sodium glucose co-transporter 2 inhibitors and impact on kidney and cardiovascular outcomes are uncertain. RESEARCH DESIGN AND METHODS: We analyzed 4395 individuals with prebaseline and postbaseline hemoglobin A1c (HbA1c) randomized to canagliflozin (n=2193) or placebo (n=2202) in The Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation trial. Effects on HbA1c were assessed using mixed models. Mediation of treatment effects by achieved glycemic control was analyzed using proportional hazards regression with and without adjustment for achieved HbA1c. End points included combined kidney or cardiovascular death, end-stage kidney disease or doubling of serum creatinine (primary trial outcome), and individual end point components. RESULTS: HbA1c lowering was modified by baseline estimated glomerular filtration rate (eGFR). For baseline eGFR 60-90, 45-59, and 30-44 mL/min/1.73 m2, overall HbA1c (canagliflozin vs placebo) decreased by -0.24%, -0.14%, and -0.08% respectively and likelihood of >0.5% decrease in HbA1c decreased with ORs of 1.47 (95% CI 1.27 to 1.67), 1.12 (0.94 to 1.33) and 0.99 (0.83 to 1.18), respectively. Adjustment for postbaseline HbA1c marginally attenuated canagliflozin effects on primary and kidney composite outcomes: unadjusted HR 0.67 (95% CI 0.57 to 0.80) and 0.66 (95% CI 0.53 to 0.81); adjusted for week 13 HbA1c, HR 0.71 (95% CI 0.060 to 0.84) and 0.68 (95% CI 0.55 to 0.83). Results adjusted for time-varying HbA1c or HbA1c as a cubic spline were similar and consistent with preserved clinical benefits across a range of excellent and poor glycemic control. CONCLUSIONS: The glycemic effects of canagliflozin are attenuated at lower eGFR but effects on kidney and cardiac end points are preserved. Non-glycemic effects may be primarily responsible for the kidney and cardioprotective benefits of canagliflozin.22.

Epidemiology of the diabetes-cardio-renal spectrum: a cross-sectional report of 1.4 million adults.

BACKGROUND: Type-2 diabetes (T2D), chronic kidney disease, and heart failure (HF) share epidemiological and pathophysiological features. Although their prevalence was described, there is limited contemporary, high-resolution, epidemiological data regarding the overlap among them. We aimed to describe the epidemiological intersections between T2D, HF, and kidney dysfunction in an entire database, overall and by age and sex. METHODS: This is a cross-sectional analysis of adults ≥ 25 years, registered in 2019 at Maccabi Healthcare Services, a large healthcare maintenance organization in Israel. Collected data included sex, age, presence of T2D or HF, and last estimated glomerular filtration rate (eGFR) in the past two years. Subjects with T2D, HF, or eGFR < 60 mL/min/1.73 m2 were defined as within the diabetes-cardio-renal (DCR) spectrum. RESULTS: Overall, 1,389,604 subjects (52.2% females) were included; 445,477 (32.1%) were 25- < 40 years, 468,273 (33.7%) were 40- < 55 years, and 475,854 (34.2%) were ≥ 55 years old. eGFR measurements were available in 74.7% of the participants and in over 97% of those with T2D or HF. eGFR availability increased in older age groups. There were 140,636 (10.1%) patients with T2D, 54,187 (3.9%) with eGFR < 60 mL/min/1.73m2, and 11,605 (0.84%) with HF. Overall, 12.6% had at least one condition within the DCR spectrum, 2.0% had at least two, and 0.23% had all three. Cardiorenal syndrome (both HF and eGFR < 60 mL/min/1.73m2) was prevalent in 0.40% of the entire population and in 2.3% of those with T2D. In patients with both HF and T2D, 55.2% had eGFR < 60 mL/min/1.73m2 and 15.8% had eGFR < 30 mL/min/1.73m2. Amongst those within the DCR spectrum, T2D was prominent in younger participants, but was gradually replaced by HF and eGFR < 60 mL/min/1.73m2 with increasing age. The congruence between all three conditions increased with age. CONCLUSIONS: This large, broad-based study provides a contemporary, high-resolution prevalence of the DCR spectrum and its components. The results highlight differences in dominance and degree of congruence between T2D, HF, and kidney dysfunction across ages.

Biochemical Urine Testing of Medication Adherence and Its Association With Clinical Markers in an Outpatient Population of Type 2 Diabetes Patients: Analysis in the DIAbetes and LifEstyle Cohort Twente (DIALECT).

OBJECTIVE: To assess adherence to the three main drug classes in real-world patients with type 2 diabetes using biochemical urine testing, and to determine the association of nonadherence with baseline demographics, treatment targets, and complications. RESEARCH DESIGN AND METHODS: Analyses were performed of baseline data on 457 patients in the DIAbetes and LifEstyle Cohort Twente (DIALECT) study. Adherence to oral antidiabetics (OADs), antihypertensives, and statins was determined by analyzing baseline urine samples using liquid chromatography-tandem mass spectrometry. Primary outcomes were microvascular and macrovascular complications and treatment targets of LDL cholesterol, HbA1c, and blood pressure. These were assessed cross-sectionally at baseline. RESULTS: Overall, 89.3% of patients were identified as adherent. Adherence rates to OADs, antihypertensives, and statins were 95.7%, 92.0%, and 95.5%, respectively. The prevalence of microvascular (81.6% vs. 66.2%; P = 0.029) and macrovascular complications (55.1% vs. 37.0%; P = 0.014) was significantly higher in nonadherent patients. The percentage of patients who reached an LDL cholesterol target of ≤2.5 mmol/L was lower (67.4% vs. 81.1%; P = 0.029) in nonadherent patients. Binary logistic regression indicated that higher BMI, current smoking, elevated serum LDL cholesterol, high HbA1c, presence of diabetic kidney disease, and presence of macrovascular disease were associated with nonadherence. CONCLUSIONS: Although medication adherence of real-world type 2 diabetes patients managed in specialist care was relatively high, the prevalence of microvascular and macrovascular complications was significantly higher in nonadherent patients, and treatment targets were reached less frequently. This emphasizes the importance of objective detection and tailored interventions to improve adherence.

Kidney, Cardiovascular, and Safety Outcomes of Canagliflozin according to Baseline Albuminuria: A CREDENCE Secondary Analysis.

BACKGROUND AND OBJECTIVES: The kidney protective effects of renin-angiotensin system inhibitors are greater in people with higher levels of albuminuria at treatment initiation. Whether this applies to sodium-glucose cotransporter 2 (SGLT2) inhibitors is uncertain, particularly in patients with a very high urine albumin-to-creatinine ratio (UACR; ≥3000 mg/g). We examined the association between baseline UACR and the effects of the SGLT2 inhibitor, canagliflozin, on efficacy and safety outcomes in the Canagliflozin and Renal Endpoints in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) randomized controlled trial. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The study enrolled 4401 participants with type 2 diabetes, an eGFR of 30 to <90 ml/min per 1.73 m2, and UACR of >300 to 5000 mg/g. Using Cox proportional hazards regression, we examined the relative and absolute effects of canagliflozin on kidney, cardiovascular, and safety outcomes according to a baseline UACR of ≤1000 mg/g (n=2348), >1000 to <3000 mg/g (n=1547), and ≥3000 mg/g (n=506). In addition, we examined the effects of canagliflozin on UACR itself, eGFR slope, and the intermediate outcomes of glycated hemoglobin, body weight, and systolic BP. RESULTS: Overall, higher UACR was associated with higher rates of kidney and cardiovascular events. Canagliflozin reduced efficacy outcomes for all UACR levels, with no evidence that relative benefits varied between levels. For example, canagliflozin reduced the primary composite outcome by 24% (hazard ratio [HR], 0.76; 95% confidence interval [95% CI], 0.56 to 1.04) in the lowest UACR subgroup, 28% (HR, 0.72; 95% CI, 0.56 to 0.93) in the UACR subgroup >1000 to <3000 mg/g, and 37% (HR, 0.63; 95% CI, 0.47 to 0.84) in the highest subgroup (Pheterogeneity=0.55). Absolute risk reductions for kidney outcomes were greater in participants with higher baseline albuminuria; the number of primary composite events prevented across ascending UACR categories were 17 (95% CI, 3 to 38), 45 (95% CI, 9 to 81), and 119 (95% CI, 35 to 202) per 1000 treated participants over 2.6 years (Pheterogeneity=0.02). Rates of kidney-related adverse events were lower with canagliflozin, with a greater relative reduction in higher UACR categories. CONCLUSIONS: Canagliflozin safely reduces kidney and cardiovascular events in people with type 2 diabetes and severely increased albuminuria. In this population, the relative kidney benefits were consistent over a range of albuminuria levels, with greatest absolute kidney benefit in those with an UACR ≥3000 mg/g. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: ClinicalTrials.gov: CREDENCE, NCT02065791. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2021_02_22_CJN15260920_final.mp3.

Visceral adipose tissue volume is associated with premature atherosclerosis in early type 2 diabetes mellitus independent of traditional risk factors.

BACKGROUND AND AIMS: Type 2 diabetes mellitus (T2DM) is commonly associated with abdominal obesity, predominantly with high visceral adipose tissue (VAT), and is accompanied by premature atherosclerosis. However, the association between VAT and subcutaneous adipose tissue (SAT) with premature atherosclerosis and (i.e. arterial) inflammation is not completely understood. To provide more insight into this association, we investigated the association between arterial 18F-fluordeoxyglucose (FDG) positron emission tomography (PET) uptake, as a measure of arterial inflammation, and metabolic syndrome (MetS) markers in early T2DM patients. METHODS: Forty-four patients with early T2DM, without glucose lowering medication, were studied (median age 63 [IQR 54-66] years, median BMI 30.4 [IQR 27.5-35.8]). Arterial inflammation was quantified using glucose corrected maximum standardized uptake value (SUVmax) FDG of the aorta, carotid, iliac, and femoral arteries, and corrected for background activity (blood pool) as target-to-background ratio (meanTBR). VAT and SAT volumes (cm3) were automatically segmented using computed tomography (CT) between levels L1-L5. Non-alcoholic fatty liver disease (NAFLD) was assessed by liver function test and CT. RESULTS: VAT volume, but not SAT volume, correlated with meanTBR (r = 0.325, p = 0.031). Linear regression models showed a significant association, even after sequential adjustment for potentially influencing MetS components. Interaction term VAT volume * sex and additional components including HbA1c, insulin resistance, NAFLD, adiponectin, leptin, and C- reactive protein (CRP) did not change the independent association between VAT volume and meanTBR. CONCLUSIONS: CT-assessed VAT volume is positively associated with FDG-PET assessed arterial inflammation, independently of factors thought to potentially mediate these effects. These findings suggest that VAT in contrast to SAT is linked to early atherosclerotic changes in T2DM patients.

Predicting kidney failure from longitudinal kidney function trajectory: A comparison of models.

RATIONALE & OBJECTIVE: Early prediction of chronic kidney disease (CKD) progression to end-stage kidney disease (ESKD) currently use Cox models including baseline estimated glomerular filtration rate (eGFR) only. Alternative approaches include a Cox model that includes eGFR slope determined over a baseline period of time, a Cox model with time varying GFR, or a joint modeling approach. We studied if these more complex approaches may further improve ESKD prediction. STUDY DESIGN: Prospective cohort. SETTING & PARTICIPANTS: We re-used data from two CKD cohorts including patients with baseline eGFR >30ml/min per 1.73m2. MASTERPLAN (N = 505; 55 ESKD events) was used as development dataset, and NephroTest (N = 1385; 72 events) for validation. PREDICTORS: All models included age, sex, eGFR, and albuminuria, known prognostic markers for ESKD. ANALYTICAL APPROACH: We trained the models on the MASTERPLAN data and determined discrimination and calibration for each model at 2 years follow-up for a prediction horizon of 2 years in the NephroTest cohort. We benchmarked the predictive performance against the Kidney Failure Risk Equation (KFRE). RESULTS: The C-statistics for the KFRE was 0.94 (95%CI 0.86 to 1.01). Performance was similar for the Cox model with time-varying eGFR (0.92 [0.84 to 0.97]), eGFR (0.95 [0.90 to 1.00]), and the joint model 0.91 [0.87 to 0.96]). The Cox model with eGFR slope showed the best calibration. CONCLUSION: In the present studies, where the outcome was rare and follow-up data was highly complete, the joint models did not offer improvement in predictive performance over more traditional approaches such as a survival model with time-varying eGFR, or a model with eGFR slope.

Urinary proteomics predict onset of microalbuminuria in normoalbuminuric type 2 diabetic patients, a sub-study of the DIRECT-Protect 2 study.

BACKGROUND: Early prevention of diabetic nephropathy is not successful as early interventions have shown conflicting results, partly because of a lack of early and precise indicators of disease development. Urinary proteomics has shown promise in this regard and could identify those at high risk who might benefit from treatment. In this study we investigate its utility in a large type 2 diabetic cohort with normoalbuminuria. METHODS: We performed a post hoc analysis in the Diabetic Retinopathy Candesartan Trials (DIRECT-Protect 2 study), a multi centric randomized clinical controlled trial. Patients were allocated to candesartan or placebo, with the aim of slowing the progression of retinopathy. The secondary endpoint was development of persistent microalbuminuria (three of four samples). We used a previously defined chronic kidney disease risk score based on proteomic measurement of 273 urinary peptides (CKD273-classifier). A Cox regression model for the progression of albuminuria was developed and evaluated with integrated discrimination improvement (IDI), continuous net reclassification index (cNRI) and receiver operating characteristic curve statistics. RESULTS: Seven hundred and thirty-seven patients were analysed and 89 developed persistent microalbuminuria (12%) with a mean follow-up of 4.1 years. At baseline the CKD273-classifier predicted development of microalbuminuria during follow-up, independent of treatment (candesartan/placebo), age, gender, systolic blood pressure, urine albumin excretion rate, estimated glomerular filtration rate, HbA1c and diabetes duration, with hazard ratio 2.5 [95% confidence interval (CI) 1.4-4.3; P = 0.002] and area under the curve 0.79 (95% CI 0.75-0.84; P < 0.0001). The CKD273-classifier improved the risk prediction (relative IDI 14%, P = 0.002; cNRI 0.10, P = 0.043). CONCLUSIONS: In this cohort of patients with type 2 diabetes and normoalbuminuria from a large intervention study, the CKD273-classifier was an independent predictor of microalbuminuria. This may help identify high-risk normoalbuminuric patients for preventive strategies for diabetic nephropathy.

Effects of Vitamin D Receptor Activation and Dietary Sodium Restriction on Residual Albuminuria in CKD: The ViRTUE-CKD Trial.

Reduction of residual albuminuria during single-agent renin-angiotensin-aldosterone blockade is accompanied by improved cardiorenal outcomes in CKD. We studied the individual and combined effects of the vitamin D receptor activator paricalcitol (PARI) and dietary sodium restriction on residual albuminuria in CKD. In a multicenter, randomized, placebo (PLAC)-controlled, crossover trial, 45 patients with nondiabetic CKD stages 1-3 and albuminuria >300 mg/24 h despite ramipril at 10 mg/d and BP<140/90 mmHg were treated for four 8-week periods with PARI (2 µg/d) or PLAC, each combined with a low-sodium (LS) or regular sodium (RS) diet. We analyzed the treatment effect by linear mixed effect models for repeated measurements. In the intention-to-treat analysis, albuminuria (geometric mean) was 1060 (95% confidence interval, 778 to 1443) mg/24 h during RS + PLAC and 990 (95% confidence interval, 755 to 1299) mg/24 h during RS + PARI (P=0.20 versus RS + PLAC). LS + PLAC reduced albuminuria to 717 (95% confidence interval, 512 to 1005) mg/24 h (P<0.001 versus RS + PLAC), and LS + PARI reduced albuminuria to 683 (95% confidence interval, 502 to 929) mg/24 h (P<0.001 versus RS + PLAC). The reduction by PARI beyond the effect of LS was nonsignificant (P=0.60). In the per-protocol analysis restricted to participants with ≥95% compliance with study medication, PARI did provide further albuminuria reduction (P=0.04 LS + PARI versus LS + PLAC). Dietary adherence was good as reflected by urinary excretion of 174±64 mmol Na+ per day in the combined RS groups and 108±61 mmol Na+ per day in the LS groups (P<0.001). In conclusion, moderate dietary sodium restriction substantially reduced residual albuminuria during fixed dose angiotensin-converting enzyme inhibition. The additional effect of PARI was small and nonsignificant.

Plasma calcidiol, calcitriol, and parathyroid hormone and risk of new onset heart failure in a population-based cohort study.

BACKGROUND: Heart failure (HF) is a major problem in the Western world, with increasing prevalence and incidence. Because HF cannot be cured, prevention of HF is of utter importance. Calcidiol, calcitriol, and parathyroid hormone (PTH) have been identified as risk factors for cardiovascular disease. However, their association with new onset HF remains to be established. We investigated whether calcidiol, calcitriol, and PTH could be used to identify those subjects at risk for new onset HF, and if they had additive predictive value over established risk predictors like N-terminal-pro Brain-type natriuretic peptide and highly sensitive Troponin-T. METHODS AND RESULTS: We examined 7470 HF-free participants in Prevention of Renal and Vascular End-stage Disease, a community-based cohort study in Groningen, the Netherlands (latitude 53°N, mean age: 49 years, 48% male). During follow-up time of 12.6 years (interquartile range: 12.3-12.9), 281 participants (4%) developed HF: 181 (66%) HF with reduced and 94 (34%) HF with preserved ejection fraction (HFrEF [left ventricular ejection fraction ≤ 40%], and HFpEF [left ventricular ejection fraction ≥ 50%], respectively). Mean (±SD) of calcidiol was 58 (±24) nmol/L, mean calcitriol 145 (±48) pmol/L, and median (interquartile range) PTH was 3.7 (3.0-4.6) pmol/L. Calcidiol levels were univariately associated with new onset HF [hazard ratio (HR) 0.82 (95% CI 0.69-0.96)], but calcitriol levels were not [HR 0.85 (95% CI 0.71-1.03)]. PTH levels kept their predictive value after adjustment for age, sex, and day of blood withdrawal (HR 1.26 [95% CI 1.04-1.53]). However, in our full model this association was lost [HR 1.10 (95% CI 0.92-1.32)]. Calcidiol, calcitriol, and PTH could not differentiate between new onset HFrEF or HFpEF. CONCLUSIONS: After adjustment for confounding factors, a single measurement of plasma calcidiol, calcitriol, or PTH was not associated with risk of developing HF. Screening for these markers to identify subjects at risk for new onset HF cannot be advocated.

Predictors of HbA1c levels in patients initiating metformin.

OBJECTIVE: The aim was to assess demographic and clinical factors as predictors of short (6 months) and long term (18 months) HbA1c levels in diabetes patients initiating metformin treatment. RESEARCH DESIGN AND METHODS: We conducted a cohort study including type 2 diabetes patients who received their first metformin prescription between 2007 and 2013 in the Groningen Initiative to Analyze Type 2 Diabetes Treatment (GIANTT) database. The primary outcome was HbA1c level at follow-up adjusted for baseline HbA1c; the secondary outcome was failing to achieve the target HbA1c level of 53 mmol/mol. Associations were analyzed by linear and logistic regression. Multiple imputation was used for missing data. Additional analyses stratified by dose and adherence level were conducted. RESULTS: The cohort included 6050 patients initiating metformin. Baseline HbA1c at target consistently predicted better HbA1c outcomes. Longer diabetes duration and lower total cholesterol level at baseline were predictors for higher HbA1c levels at 6 months. At 18 months, cholesterol level was not a predictor. Longer diabetes duration was also associated with not achieving the target HbA1c at follow-up. The association for longer diabetes duration was especially seen in patients starting on low dose treatment. No consistent associations were found for comorbidity and comedication. CONCLUSIONS: Diabetes duration was a relevant predictor of HbA1c levels after 6 and 18 months of follow-up in patients initiating metformin treatment. Given the study design, no causal inference can be made. Our study suggests that prompt treatment intensification may be needed in patients who have a longer diabetes duration at treatment initiation.

Association of Skin Autofluorescence Levels With Kidney Function Decline in Patients With Peripheral Artery Disease.

OBJECTIVE: Skin autofluorescence (SAF), a measure of advanced glycation end product accumulation, is associated with kidney function. We investigated the association of SAF with rate of kidney function decline in a cohort of patients with peripheral artery disease. APPROACH AND RESULTS: We performed a post hoc analysis of an observational longitudinal cohort study. We included 471 patients with peripheral artery disease, and SAF was measured at baseline. Primary end point was rate of estimated glomerular filtration rate (eGFR) decline. Secondary end points were incidence of eGFR <60 and <45 mL/min/1.73 m(2) and rapid eGFR decline, defined as a decrease in eGFR of >5 mL/min/1.73 m(2)/y. During a median follow-up of 3 years, the mean change in eGFR per year was -1.8±4.4 mL/min/1.73 m(2)/y. No significant difference in rate of eGFR decline was observed per 1 arbitrary unit increase in SAF (-0.1 mL/min/1.73 m(2)/y; 95% confidence interval, -0.7 to 0.5; P=0.8). Analyses of the secondary end points showed that there was an association of SAF with incidence of eGFR <60 and <45 mL/min/1.73 m(2) (hazard ratio, 1.54; 95% confidence interval, 1.13-2.10; P=0.006 and hazard ratio, 1.76; 95% confidence interval, 1.20-2.59; P=0.004, respectively), but after adjustment for age and sex, significance was lost. There was no association of SAF with rapid eGFR decline. CONCLUSIONS: In conclusion, in this cohort of patients with peripheral artery disease, elevated SAF was associated with lower baseline eGFR. Although SAF has previously been established as a predictor for cardiovascular disease and mortality, it did not predict the rate of kidney function decline during follow-up in this study.

High urinary sulfate concentration is associated with reduced risk of renal disease progression in type 2 diabetes.

Diabetes is associated with a high incidence of microvascular disease, including nephropathy. Diabetic nephropathy is the most common cause of chronic kidney disease in the Western world. Sulfate in the urine is the metabolic end product of hydrogen sulfide (H2S), a recent discovered gaseous signaling molecule. Urinary sulfate has earlier shown beneficial predictive properties in renal transplant recipients. Based on the protective role of exogenous H2S in experimental models of diabetic nephropathy, we aimed to cross-sectionally investigate the association of sulfate with renal risk markers, and to prospectively investigate its predictive value for renal events in patients with diabetic nephropathy. Post-hoc analysis on data of the sulodexide macroalbuminuria (Sun-MACRO) trial and the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study was performed. A total of 1004 patients with type 2 diabetes were included. Urinary sulfate concentration was measured and cross-sectionally associated to renal risk markers by linear regression. Multivariable Cox regression analysis was performed to assess the prospective association of sulfate with renal events, which was defined as end stage renal disease or a doubling of baseline serum creatinine. Mean age was 63 ± 9 years, median sulfate concentration was 8.0 (IQR 5.8-11.4) mmol/L. Urinary sulfate positively associated with male gender, hemoglobin, and negatively associated with albuminuria at baseline. During follow-up for 12 (IQR 6-18) months, 38 renal events occurred. Each doubling of urinary sulfate was associated with a 19% (95%CI 1%-34%) lower risk of renal events, independent of adjustment for potential confounders, including age, estimated glomerular filtration rate (eGFR), and albuminuria. To conclude, higher urinary sulfate concentration is associated with a more beneficial profile of renal risk markers, and is independently associated with a reduced risk for renal events in type 2 diabetes patients with nephropathy.

Utility of the CKD273 peptide classifier in predicting chronic kidney disease progression.

BACKGROUND: Chronic kidney disease (CKD) is a growing public health concern, afflicting approximately one-tenth of adults in developed countries. However, the clinical need for an accurate test, such as a biomarker and/or peptide classifier, for predicting CKD progression and related adverse outcomes remains unaddressed. Recently, a proteomics approach based on capillary electrophoresis-mass spectrometry was employed to develop a urinary peptide-based high-dimensional classifier, namely CKD273, for predicting CKD progression. OBJECTIVES: The study aims to critically appraise the evidence level of the CKD273 classifier's utility in predicting CKD progression, according to the Oxford Evidence-Based Medicine (EBM) and Strength of Recommendation Taxonomy (SORT) guidelines. METHODS: Eligible studies were identified by a literature search of MEDLINE and Web of Science Expanded Core Collection databases. Limitations were set to prospective cohort studies evaluating the classifier's accuracy in predicting CKD progression. Data extraction was undertaken according to a predefined protocol by two independent reviewers. The EBM and SORT guidelines were applied to appraise the CKD273 classifier's utility for predicting CKD progression. RESULTS: The query search results rendered four prospective cohort studies. The classifier performed independently of age, gender and the type of urine storage containers used. The classifier predicted the development of micro- or macroalbuminuria and rapid decline (i.e. >-5% annual decrease) in the estimated glomerular filtration rate. One study assessed the association of the classifier with end-stage renal disease and death but did not take confounding factors into account. The CKD273 classifier attained high evidence levels according to the EBM (score range 1b), supporting its utility for predicting CKD progression. However, lower scores were attained when the studies were scored according the SORT guidelines (score ranges 1-4). CONCLUSIONS: Initial promising evidence supports the CKD273 classifier's utility in predicting CKD progression. The classifier's applicability should be corroborated with additional evidence arising from inception cohort studies assessing patient-oriented outcomes, which demonstrate its added value beyond currently available clinical risk predictors, as well as its cost-effectiveness in clinical practice.

Prediction of the effect of atrasentan on renal and heart failure outcomes based on short-term changes in multiple risk markers.

BACKGROUND: A recent phase II clinical trial (Reducing Residual Albuminuria in Subjects with Diabetes and Nephropathy with AtRasentan trial and an identical trial in Japan (RADAR/JAPAN)) showed that the endothelin A receptor antagonist atrasentan lowers albuminuria, blood pressure, cholesterol, hemoglobin, and increases body weight in patients with type 2 diabetes and nephropathy. We previously developed an algorithm, the Parameter Response Efficacy (PRE) score, which translates short-term drug effects into predictions of long-term effects on clinical outcomes. DESIGN: We used the PRE score on data from the RADAR/JAPAN study to predict the effect of atrasentan on renal and heart failure outcomes. METHODS: We performed a post-hoc analysis of the RADAR/JAPAN randomized clinical trials in which 211 patients with type-2 diabetes and nephropathy were randomly assigned to atrasentan 0.75 mg/day, 1.25 mg/day, or placebo. A PRE score was developed in a background set of completed clinical trials using multivariate Cox models. The score was applied to baseline and week-12 risk marker levels of RADAR/JAPAN participants, to predict atrasentan effects on clinical outcomes. Outcomes were defined as doubling serum creatinine or end-stage renal disease and hospitalization for heart failure. RESULTS: The PRE score predicted renal risk changes of -23% and -30% for atrasentan 0.75 and 1.25 mg/day, respectively. PRE scores also predicted a small non-significant increase in heart failure risk for atrasentan 0.75 and 1.25 mg/day (+2% vs. +7%). Selecting patients with >30% albuminuria reduction from baseline (responders) improved renal outcome to almost 50% risk reduction, whereas non-responders showed no renal benefit. CONCLUSIONS: Based on the RADAR/JAPAN study, with short-term changes in risk markers, atrasentan is expected to decrease renal risk without increased risk of heart failure. Within this population albuminuria responders appear to contribute to the predicted improvements, whereas non-responders showed no benefit. The ongoing hard outcome trial (SONAR) in type 2 diabetic patients with >30% albuminuria reduction to atrasentan will allow us to assess the validity of these predictions.

Urine Albumin-Creatinine Ratio Versus Albumin Excretion for Albuminuria Staging: A Prospective Longitudinal Cohort Study.

BACKGROUND: New guidelines advocate the use of albumin-creatinine ratio (ACR) in a urine sample instead of 24-hour urinary albumin excretion (UAE) for staging albuminuria. Concern has been expressed that this may result in misclassification for reasons including interindividual differences in urinary creatinine excretion. STUDY DESIGN: Prospective longitudinal cohort study. SETTING & PARTICIPANTS: We examined 7,623 participants of the PREVEND and RENAAL studies for reclassified when using ACR instead of 24-hour UAE, the characteristics of reclassified participants, and their outcomes. Albuminuria was categorized into 3 ACR and UAE categories: <30, 30 to 300, and >300mg/g or mg/24 h, respectively. PREDICTORS: Baseline ACR and 24-hour UAE. OUTCOMES: Cardiovascular (CV) morbidity and mortality and all-cause mortality. RESULTS: When using ACR in the early morning void instead of 24-hour UAE, 88% of participants were classified in corresponding albuminuria categories. 307 (4.0%) participants were reclassified to a higher, and 603 (7.9%), to a lower category. Participants who were reclassified to a higher ACR category in general had a worse CV risk profile compared with nonreclassified participants, whereas the reverse was true for participants reclassified to a lower ACR category. Similarly, Cox proportional hazards regression analyses showed that reclassification to a higher ACR category was associated with a tendency for increased risk for CV morbidity and mortality and all-cause mortality, whereas reclassification to a lower ACR category was associated with a tendency for lower risk. Net reclassification improvement, adjusted for age, sex, and duration of follow-up, was 0.107 (P=0.002) for CV events and 0.089 (P<0.001) for all-cause mortality. LIMITATIONS: Early morning void urine collection instead of spot urine collection. CONCLUSIONS: Our results indicate that there is high agreement between early morning void ACR and 24-hour UAE categories. Reclassification is therefore limited, but when present, is generally indicative of the presence of CV risk factors and prognosis.

Vitamin D receptor activator and dietary sodium restriction to reduce residual urinary albumin excretion in chronic kidney disease (ViRTUE study): rationale and study protocol.

UNLABELLED: Optimal albuminuria reduction is considered essential to halting chronic kidney disease (CKD) progression. Both vitamin D receptor activator (VDRA) treatment and dietary sodium restriction potentiate the efficacy of renin-angiotensin-aldosterone-system (RAAS) blockade to reduce albuminuria. The ViRTUE study addresses whether a VDRA in combination with dietary sodium restriction provides further albuminuria reduction in non-diabetic CKD patients on top of RAAS blockade. The ViRTUE study is an investigator-initiated, prospective, multi-centre, randomized, double-blind (paricalcitol versus placebo), placebo-controlled trial targeting stage 1-3 CKD patients with residual albuminuria of >300 mg/day due to non-diabetic glomerular disease, despite angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use. During run-in, all subjects switched to standardized RAAS blockade (ramipril 10 mg/day) and blood pressure titrated to <140/90 mmHg according to a standardized protocol. Eligible patients are subsequently enrolled and undergo four consecutive study periods in random order of 8 weeks each: (i) paricalcitol (2 µg/day) combined with a liberal sodium diet (∼200 mmol Na(+)/day, i.e. mean sodium intake in the general population), (ii) paricalcitol (2 µg/day) combined with dietary sodium restriction (target: 50 mmol Na(+)/day), (iii) placebo combined with a liberal sodium diet and (iv) placebo combined with dietary sodium restriction. Data are collected at the end of each study period. The primary outcome is 24-h urinary albumin excretion. Secondary study outcomes are blood pressure, renal function (estimated glomerular filtration rate), plasma renin activity and, in a sub-population (N = 9), renal haemodynamics (measured glomerular filtration rate and effective renal plasma flow). A sample size of 50 patients provides 90% power to detect a 23% reduction in albuminuria, assuming a 25% dropout rate. Further reduction of residual albuminuria by combination of VDRA treatment and sodium restriction during single-agent RAAS-blockade will justify long-term studies on cardiorenal outcomes and safety. CLINICAL TRIAL REGISTRATION: NTR2898 (Dutch trial register).

The association of albuminuria and high-sensitivity C-reactive protein with the efficacy of HMG-coenzyme A reductase inhibitors for cardiovascular event prevention.

BACKGROUND: It is not clear which hypercholesterolemic patients benefit most from ß-hydroxy-ß-methylglutaryl coenzyme A reductase inhibitors with respect to the prevention of cardiovascular events. Early signs of atherosclerotic vascular damage may identify high-risk patients. DESIGN: We studied whether subjects with hypercholesterolemia will benefit more from starting statin treatment in the case of high albuminuria and/or high-sensitivity C-reactive protein (hsCRP). METHODS: Included were subjects who had hypercholesterolemia at baseline, a negative cardiovascular disease history and who were not treated with statins. In total, 2011 subjects were analysed, of whom 695 started with a statin during a follow-up of 7.0 ± 1.7 years. Adjusted hazard ratios (HRs) for cardiovascular events were calculated in subjects who started versus those who did not start a statin stratified for albuminuria less than or ≥ 15 mg/day and/or hsCRP less than or ≥ 3 mg/L. RESULTS: The start of a statin was associated with a beneficial effect on cardiovascular risk in subjects with high albuminuria (HR 0.38 (0.23-0.60)), while the effect of starting a statin was non-significant in subjects with low albuminuria (HR 0.74 (0.44-1.24), P for interaction < 0.05). The effect of starting a statin was similar in subgroups with high and low hsCRP (P for interaction 0.34). When combining albuminuria and hsCRP subgroups, the start of statin treatment was associated with a lower risk of cardiovascular events dependent on albuminuria and not on the hsCRP level. CONCLUSIONS: The start of statin treatment is associated with a significantly lower absolute as well as relative risk of cardiovascular events in subjects with hypercholesterolemia and elevated albuminuria, whereas these drugs had less effect in subjects with normal albuminuria.