Glomerular and tubular effects of dapagliflozin, eplerenone and their combination in patients with chronic kidney disease: A post-hoc analysis of the ROTATE-3 study.

AIM: Sodium-glucose co-transporter 2 inhibitors and mineralocorticoid receptor antagonists reduce albuminuria and the risk of kidney failure. The aim of this study was to investigate the effects of both agents alone and in combination on markers of the glomerular endothelial glycocalyx and tubular function. METHODS: This post-hoc analysis utilized data of the ROTATE-3 study, a randomized cross-over study in 46 adults with chronic kidney disease and urinary albumin excretion ≥100 mg/24 h, who were treated for 4 weeks with dapagliflozin, eplerenone or its combination. The effects of dapagliflozin, eplerenone and the combination on outcome measures such as heparan sulphate, neuro-hormonal markers and tubular sodium handling were assessed with mixed repeated measures models. RESULTS: The mean percentage change from baseline in heparan sulphate after 4 weeks treatment with dapagliflozin, eplerenone or dapagliflozin-eplerenone was -34.8% (95% CI -52.2, -10.9), -5.9% (95% CI -32.5, 31.3) and -28.1% (95% CI -48.4, 0.1) respectively. The mean percentage change from baseline in plasma aldosterone was larger with eplerenone [38.9% (95% CI 2.8, 87.7)] and dapagliflozin-eplerenone [32.2% (95% CI -1.5, 77.4)], compared with dapagliflozin [-12.5% (95% CI -35.0, 17.8)], respectively. Mean percentage change from baseline in copeptin with dapagliflozin, eplerenone or dapagliflozin-eplerenone was 28.4% (95% CI 10.7, 49.0), 4.2% (95% CI -10.6, 21.4) and 23.8% (95% CI 6.6, 43.9) respectively. Dapagliflozin decreased proximal absolute sodium reabsorption rate by 455.9 mmol/min (95% CI -879.2, -32.6), while eplerenone decreased distal absolute sodium reabsorption rate by 523.1 mmol/min (95% CI -926.1, -120.0). Dapagliflozin-eplerenone decreased proximal absolute sodium reabsorption [-971.0 mmol/min (95% CI -1411.0, -531.0)], but did not affect distal absolute sodium reabsorption [-9.2 mmol/min (95% CI -402.0, 383.6)]. CONCLUSIONS: Dapagliflozin and eplerenone exert different effects on markers of glomerular and tubular function supporting the hypothesis that different mechanistic pathways may account for their kidney protective effects.

Sevelamer Use and Mortality in People with Chronic Kidney Disease Stages 4 and 5 Not on Dialysis.

Rationale and objective: Data suggest that non-calcium-based binders, and specifically sevelamer, may lead to lower rates of death when compared with calcium-based binders in end-stage renal disease (ESRD) patients. However, the association between sevelamer use and mortality for those with non-dialysis-dependent chronic kidney disease (NDD-CKD) patients has been uncertain. Study design: Our research is presented in a prospective cohort study. Setting and participants: A total of 966 participants with NDD-CKD stages 4-5 were enrolled in the PECERA study from 12 centers in Spain. Exposure: The participants were treated with sevelamer. Outcome: This study yielded all-cause and cardiovascular mortality outcomes. Analytical approach: We conducted an association analysis between mortality and sevelamer use with time-dependent Cox proportional hazards models. Results: After a median follow-up of 29 months (IQR: 13-36 months), death occurred in 181 participants (19%), with cardiovascular (n = 95, 53%) being the leading cause of death. In a multivariable model, the adjusted hazard ratios (HRs) for patients under sevelamer treatment were 0.44 (95% CI, 0.22 to 0.88) and 0.37 (95% CI, 0.18 to 0.75) for all-cause and cardiovascular mortality, respectively, compared with those of untreated patients. Limitations: Some limitations include potential confusion via indication bias; causal statements about these associations cannot be made due to the observational nature of this study. Conclusions: In this prospective NDD-CKD cohort study, the administration of sevelamer was independently associated with lower all-cause and cardiovascular mortality, suggesting that non-calcium-based phosphate binders might be the first-line therapy for phosphate lowering in this population. Further interventional studies clarifying the risks and benefits of phosphate binders in NDD-CKD are warranted.

Vitamin D and Chronic Kidney Disease Association with Mineral and Bone Disorder: An Appraisal of Tangled Guidelines.

Chronic kidney disease (CKD) is a highly prevalent condition worldwide in which the kidneys lose many abilities, such as the regulation of vitamin D (VD) metabolism. Moreover, people with CKD are at a higher risk of multifactorial VD deficiency, which has been extensively associated with poor outcomes, including bone disease, cardiovascular disease, and higher mortality. Evidence is abundant in terms of the association of negative outcomes with low levels of VD, but recent studies have lowered previous high expectations regarding the beneficial effects of VD supplementation in the general population. Although controversies still exist, the diagnosis and treatment of VD have not been excluded from nephrology guidelines, and much data still supports VD supplementation in CKD patients. In this narrative review, we briefly summarize evolving controversies and useful clinical approaches, underscoring that the adverse effects of VD derivatives must be balanced against the need for effective prevention of progressive and severe secondary hyperparathyroidism. Guidelines vary, but there seems to be general agreement that VD deficiency should be avoided in CKD patients, and it is likely that one should not wait until severe SHPT is present before cautiously starting VD derivatives. Furthermore, it is emphasized that the goal should not be the complete normalization of parathyroid hormone (PTH) levels. New developments may help us to better define optimal VD and PTH at different CKD stages, but large trials are still needed to confirm that VD and precise control of these and other CKD-MBD biomarkers are unequivocally related to improved hard outcomes in this population.

Glucagon-Like Peptide-1 Receptor Agonist Use in People Living with Type 2 Diabetes Mellitus and Chronic Kidney Disease: A Narrative Review of the Key Evidence with Practical Considerations.

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are incretin-mimetic agents that are effective adjuncts in the treatment of diabetes. This class of medications is also associated with promoting weight loss and a low risk of hypoglycemia, and some have been shown to be associated with a significant reduction of major cardiovascular events. Mounting evidence suggests that GLP-1 RAs have benefits beyond reducing blood glucose that include improving kidney function in people living with type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD), a common microvascular complication of T2DM. Several large clinical studies, the majority of which are cardiovascular outcome trials, indicate that GLP-1 RA therapy is safe and tolerable for people living with T2DM and compromised renal function, and also suggest that GLP-1 RAs may have renoprotective properties. Although evidence from clinical trials has shown GLP-1 RAs to be safe and efficacious in people living with T2DM and renal impairment, their use is uncommon in this patient population. With continuing developments in the field of GLP-1 RA therapy, it is important for physicians to understand the benefits and practical use of GLP-1 RAs, as well as the clinical evidence, in order to achieve positive patient outcomes. Here, we review evidence on GLP-1 RA use in people living with T2DM and CKD and summarize renal outcomes from clinical studies. We provide practical considerations for GLP-1 RA use to provide an added benefit to guide treatment in this high-risk patient population.

Type 2 diabetes mellitus (T2DM) is a common disorder characterized by insulin resistance and dysfunction of insulin-producing beta cells of the pancreas. People living with T2DM have an increased risk of developing complications, including chronic kidney disease (CKD), which itself is associated with increased mortality. Both the American Diabetes Association and Kidney Disease Improving Global Outcomes organization provide updated pharmacological recommendations for treating T2DM in people with CKD that include the use of sodium-glucose co-transporter-2 inhibitors (SGLT2i) or glucagon-like peptide-1 receptor agonists (GLP-1 RAs). GLP-1 RAs are effective and safe treatments for controlling blood sugar levels and reducing body weight, and evidence from large clinical trials also suggests that GLP-1 RAs may be renoprotective. Despite the benefits of GLP-1 RAs, they are not commonly prescribed in people living with T2DM and CKD. Healthcare practitioners need to be aware of the most recent information so that they can make informed decisions when selecting treatment options. The objective of this review is to summarize the main renal outcomes from clinical studies while providing practical guidance on the use of GLP-1 RAs.

Silver jubilee: 25 years of the first demonstration of the direct effect of phosphate on the parathyroid cell.

Although phosphorus is an essential element for life, it is not found in nature in its native state but rather combined in the form of inorganic phosphates (PO43-), with tightly regulated plasma levels that are associated with deleterious effects and mortality when these are out of bounds. The growing interest in the accumulation of PO43- in human pathophysiology originated in its attributed role in the pathogenesis of secondary hyperparathyroidism (SHPT) in chronic kidney disease. In this article, we review the mechanisms by which this effect was justified and we commemorate the important contribution of a Spanish group led by Dr. M. Rodríguez, just 25 years ago, when they first demonstrated the direct effect of PO43- on the regulation of the synthesis and secretion of parathyroid hormone by maintaining the structural integrity of the parathyroid glands in their original experimental model. In addition to demonstrating the importance of arachidonic acid (AA) and the phospholipase A2-AA pathway as a mediator of parathyroid gland response, these findings were predecessors of the recent description of the important role of PO43- on the activity of the calcium sensor-receptor, and also fueled various lines of research on the importance of PO43- overload not only for the pathophysiology of SHPT but also in its systemic pathogenic role.

Survival with low- and high-flux dialysis.

BACKGROUND: Besides advances in haemodialysis (HD), mortality rates are still high. The effect of the different types of HD membranes on survival is still a controversial issue. The aim of this COSMOS (Current management Of Secondary hyperparathyroidism: a Multicentre Observational Study) analysis was to survey, in HD patients, the relationship between the use of conventional low- or high-flux membranes and all-cause and cardiovascular mortality. METHODS: COSMOS is a multicentre, open-cohort, 3-year prospective study, designed to evaluate mineral and bone disorders in the European HD population. The present analysis included 5138 HD patients from 20 European countries, 3502 randomly selected at baseline (68.2%), plus 1636 new patients with <1 year on HD (31.8%) recruited to replace patients who died, were transplanted, switched to peritoneal dialysis or lost to follow-up by other reasons. Cox-regression analysis with time-dependent variables, propensity score matching and the use of an instrumental variable (facility-level analysis) were used. RESULTS: After adjustments using three different multivariate models, patients treated with high-flux membranes showed a lower all-cause and cardiovascular mortality risks {hazard ratio (HR) = 0.76 [95% confidence interval (CI) 0.61-0.96] and HR = 0.61 (95% CI 0.42-0.87), respectively}, that remained significant after matching by propensity score for all-cause mortality (HR = 0.69, 95% CI 0.52-0.93). However, a facility-level analysis showed no association between the case-mix-adjusted facility percentage of patients dialysed with high-flux membranes and all-cause and cardiovascular mortality. CONCLUSIONS: High-flux dialysis was associated with a lower relative risk of all-cause and cardiovascular mortality. However, dialysis facilities using these dialysis membranes to a greater extent did not show better survival.

Effects of canagliflozin on serum potassium in people with diabetes and chronic kidney disease: the CREDENCE trial.

AIMS: Hyperkalaemia is a common complication of type 2 diabetes mellitus (T2DM) and limits the optimal use of agents that block the renin-angiotensin-aldosterone system, particularly in patients with chronic kidney disease (CKD). In patients with CKD, sodium‒glucose cotransporter 2 (SGLT2) inhibitors provide cardiorenal protection, but whether they affect the risk of hyperkalaemia remains uncertain. METHODS AND RESULTS: The CREDENCE trial randomized 4401 participants with T2DM and CKD to the SGLT2 inhibitor canagliflozin or matching placebo. In this post hoc analysis using an intention-to-treat approach, we assessed the effect of canagliflozin on a composite outcome of time to either investigator-reported hyperkalaemia or the initiation of potassium binders. We also analysed effects on central laboratory-determined hyper- and hypokalaemia (serum potassium ≥6.0 and <3.5 mmol/L, respectively) and change in serum potassium. At baseline, the mean serum potassium in canagliflozin and placebo arms was 4.5 mmol/L; 4395 (99.9%) participants were receiving renin-angiotensin system blockade. The incidence of investigator-reported hyperkalaemia or initiation of potassium binders was lower with canagliflozin than with placebo [occurring in 32.7 vs. 41.9 participants per 1000 patient-years; hazard ratio (HR) 0.78, 95% confidence interval (CI) 0.64-0.95, P = 0.014]. Canagliflozin similarly reduced the incidence of laboratory-determined hyperkalaemia (HR 0.77, 95% CI 0.61-0.98, P = 0.031), with no effect on the risk of hypokalaemia (HR 0.92, 95% CI 0.71-1.20, P = 0.53). The mean serum potassium over time with canagliflozin was similar to that of placebo. CONCLUSION: Among patients treated with renin-angiotensin-aldosterone system inhibitors, SGLT2 inhibition with canagliflozin may reduce the risk of hyperkalaemia in people with T2DM and CKD without increasing the risk of hypokalaemia.

Clinical Approach to Vascular Calcification in Patients With Non-dialysis Dependent Chronic Kidney Disease: Mineral-Bone Disorder-Related Aspects.

Chronic kidney disease (CKD) is associated with a very high morbimortality, mainly from cardiovascular origin, and CKD is currently considered in the high- or very high risk- cardiovascular risk category. CKD-mineral and bone disorders (CKD-MBDs), including vascular and/or valvular calcifications, are also associated with these poor outcomes. Vascular calcification (VC) is very prevalent (both intimal and medial), even in non-dialysis dependent patients, with a greater severity and more rapid progression. Simple X-ray based-scores such as Adragão's (AS) are useful prognostic tools and AS (even AS based on hand-X-ray only) may be superior to the classic Kauppila's score when evaluating non-dialysis CKD patients. Thus, in this mini-review, we briefly review CKD-MBD-related aspects of VC and its complex pathophysiology including the vast array of contributors and inhibitors. Furthermore, although VC is a surrogate marker and is not yet considered a treatment target, we consider that the presence of VC may be relevant in guiding therapeutic interventions, unless all patients are treated with the mindset of reducing the incidence or progression of VC with the currently available armamentarium. Avoiding phosphate loading, restricting calcium-based phosphate binders and high doses of vitamin D, and avoiding normalizing (within the normal limits for the assay) parathyroid hormone levels seem logical approaches. The availability of new drugs and future studies, including patients in early stages of CKD, may lead to significant improvements not only in patient risk stratification but also in attenuating the accelerated progression of VC in CKD.

Blood Pressure Effects of Canagliflozin and Clinical Outcomes in Type 2 Diabetes and Chronic Kidney Disease: Insights From the CREDENCE Trial.

BACKGROUND: People with type 2 diabetes and chronic kidney disease experience a high burden of hypertension, but the magnitude and consistency of blood pressure (BP) lowering with canagliflozin in this population are uncertain. Whether the effects of canagliflozin on kidney and cardiovascular outcomes vary by baseline BP or BP-lowering therapy is also unknown. METHODS: The CREDENCE trial (Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation) randomized people with type 2 diabetes and chronic kidney disease to canagliflozin or placebo. In a post hoc analysis, we investigated the effect of canagliflozin on systolic BP across subgroups defined by baseline systolic BP, number of BP-lowering drug classes, and history of apparent treatment-resistant hypertension (BP ≥130/80 mm Hg while receiving ≥3 classes of BP-lowering drugs, including a diuretic). We also assessed whether effects on clinical outcomes differed across these subgroups. RESULTS: The trial included 4401 participants, of whom 3361 (76.4%) had baseline systolic BP ≥130 mm Hg, and 1371 (31.2%) had resistant hypertension. By week 3, canagliflozin reduced systolic BP by 3.50 mm Hg (95% CI, -4.27 to -2.72), an effect maintained over the duration of the trial, with similar reductions across BP and BP-lowering therapy subgroups (all P interaction ≥0.05). Canagliflozin also reduced the need for initiation of additional BP-lowering agents during the trial (hazard ratio, 0.68 [95% CI, 0.61-0.75]). The effect of canagliflozin on kidney failure, doubling of serum creatinine, or death caused by kidney or cardiovascular disease (hazard ratio, 0.70 [95% CI, 0.59-0.82]) was consistent across BP and BP-lowering therapy subgroups (all P interaction ≥0.35), as were effects on other key kidney, cardiovascular, and safety outcomes. CONCLUSIONS: In people with type 2 diabetes and chronic kidney disease, canagliflozin lowers systolic BP across all BP-defined subgroups and reduces the need for additional BP-lowering agents. These findings support use of canagliflozin for end-organ protection and as an adjunct BP-lowering therapy in people with chronic kidney disease. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02065791.

Disorders in bone-mineral parameters and the risk of death in persons with chronic kidney disease stages 4 and 5: the PECERA study.

BACKGROUND: Abnormalities of bone mineral parameters are associated with increased mortality in patients on dialysis, but their effects and the optimal range of these biomarkers are less well characterized in non-dialysis chronic kidney disease (CKD). METHODS: PECERA (Collaborative Study Project in Patients with Advanced CKD) is a 3-year, prospective multicenter, open-cohort study of 966 adult patients with non-dialyzed CKD stages 4-5 enrolled from 12 centers in Spain. Associations between levels of serum calcium (Ca) (corrected for albumin), phosphate (P), and intact parathyroid hormone (iPTH) with all-cause mortality (primary outcome) and cardiovascular mortality (secondary outcome) were examined using time-dependent Cox proportional hazards models and penalized splines analysis adjusted by demographics and comorbidities, treatments and biochemical values collected every 6 months for 3 years. RESULTS: After a median follow-up of 29 months (IQR: 13-36 months) there were 181 deaths (19%). The association of calcium with all-cause mortality was J-shaped, with an increased risk for all-cause mortality at levels > 10.5 mg/dL. For phosphate and iPTH levels, the association was U-shaped. The serum values associated with the minimum risk of mortality were 3.8 mg/dL for phosphate and 70 pg/mL for iPTH, being the lowest risk ranges between 2.8 and 5.0 mg/dL, and between 38 and 112 pg/mL for phosphate and iPTH, respectively. CONCLUSIONS: Our study provides evidence on the non-linear association of serum calcium, phosphate and iPTH levels with mortality in stage 4 and 5 CKD patients, and suggests potential survival benefits for controlling bone mineral parameters in this population, as previously reported for dialysis patients.

Early urinary sodium trajectory and risk of adverse outcomes in acute heart failure and renal dysfunction.

INTRODUCTION AND OBJECTIVES: Urinary sodium (UNa+) has emerged as a useful biomarker of poor clinical outcomes in acute heart failure (AHF). Here, we sought to evaluate: a) the usefulness of a single early determination of UNa+ for predicting adverse outcomes in patients with AHF and renal dysfunction, and b) whether the change in UNa+ at 24hours (ΔUNa24h) adds any additional prognostic information over baseline values. METHODS: This is a post-hoc analysis of a multicenter, open-label, randomized clinical trial (IMPROVE-HF) (ClinicalTrials.gov NCT02643147) that randomized 160 patients with AHF and renal dysfunction on admission to a) the standard diuretic strategy, or b) a carbohydrate antigen 125-guided diuretic strategy. The primary end point was all-cause mortality and total all-cause readmissions. RESULTS: The mean age was 78±8 years, and the mean glomerular filtration rate was 34.0±8.5mL/min/1.73 m2. The median UNa+ was 90 (65-111) mmol/L. At a median follow-up of 1.73 years [interquartile range, 0.48-2.35], 83 deaths (51.9%) were registered, as well as 263 all-cause readmissions in 110 patients. UNa+ was independently associated with mortality (HR, 0.75; 95%CI, 0.65-0.87; P <.001) and all-cause readmissions (HR, 0.92; 95%CI, 0.88-0.96; P <.001). The prognostic usefulness of the ΔUNa24h varied according to UNa+ at admission (P for interaction <.05). The ΔUNa24h was inversely associated with both end points only in the group with UNa+ ≤ 50 mmol/L. Conversely, no effect was found in the group with UNa+> 50 mmol/L. CONCLUSIONS: In patients with AHF and renal dysfunction, a single early determination of UNa+ ≤ 50 mmol/L identifies patients with a higher risk of all-cause mortality and readmission. The ΔUNa24h adds prognostic information over baseline values only when UNa+ at admission is ≤ 50 mmol/L.

CA125-Guided Diuretic Treatment Versus Usual Care in Patients With Acute Heart Failure and Renal Dysfunction.

BACKGROUND: The optimal diuretic treatment strategy for patients with acute heart failure and renal dysfunction remains unclear. Plasma carbohydrate antigen 125 (CA125) is a surrogate of fluid overload and a potentially valuable tool for guiding decongestion therapy. The aim of this study was to determine if a CA125-guided diuretic strategy is superior to usual care in terms of short-term renal function in patients with acute heart failure and renal dysfunction at presentation. METHODS: This multicenter, open-label study randomized 160 patients with acute heart failure and renal dysfunction into 2 groups (1:1). Loop diuretics doses were established according to CA125 levels in the CA125-guided group (n = 79) and in clinical evaluation in the usual-care group (n = 81). Changes in estimated glomerular filtration rate (eGFR) at 72 and 24 hours were the co-primary endpoints, respectively. RESULTS: The mean age was 78 ± 8 years, the median amino-terminal pro-brain natriuretic peptide was 7765 pg/mL, and the mean eGFR was 33.7 ± 11.3 mL/min/1.73m2. Over 72 hours, the CA125-guided group received higher furosemide equivalent dose compared to usual care (P = 0.011), which translated into higher urine volume (P = 0.042). Moreover, patients in the active arm with CA125 >35 U/mL received the highest furosemide equivalent dose (P <0.001) and had higher diuresis (P = 0.013). At 72 hours, eGFR (mL/min/1.73m2) significantly improved in the CA125-guided group (37.5 vs 34.8, P = 0.036), with no significant changes at 24 hours (35.8 vs 39.5, P = 0.391). CONCLUSION: A CA125-guided diuretic strategy significantly improved eGFR and other renal function parameters at 72 hours in patients with acute heart failure and renal dysfunction.

Serum phosphate optimal timing and range associated with patients survival in haemodialysis: the COSMOS study.

BACKGROUND: Serum phosphate is a key parameter in the management of chronic kidney disease-mineral and bone disorder (CKD-MBD). The timing of phosphate measurement is not standardized in the current guidelines. Since the optimal range of these biomarkers may vary depending on the duration of the interdialytic interval, in this analysis of the Current management of secondary hyperparathyroidism: a multicentre observational study (COSMOS), we assessed the influence of a 2- (midweek) or 3-day (post-weekend) dialysis interval for blood withdrawal on serum levels of CKD-MBD biomarkers and their association with mortality risk. METHODS: The COSMOS cohort (6797 patients, CKD Stage 5D) was divided into two groups depending upon midweek or post-weekend blood collection. Univariate and multivariate Cox's models adjusted hazard ratios (HRs) by demographics and comorbidities, treatments and biochemical parameters from a patient/centre database collected at baseline and every 6 months for 3 years. RESULTS: There were no differences in serum calcium or parathyroid hormone levels between midweek and post-weekend patients. However, in post-weekend patients, the mean serum phosphate levels were higher compared with midweek patients (5.5 ± 1.4 versus 5.2 ± 1.4 mg/dL, P < 0.001). Also, the range of serum phosphate with the lowest mortality risk [HR ≤ 1.1; midweek: 3.5-4.9 mg/dL (95% confidence interval, CI: 2.9-5.2 mg/dL); post-weekend: 3.8-5.7 mg/dL (95% CI: 3.0-6.4 mg/dL)] showed significant differences in the upper limit (P = 0.021). CONCLUSION: Midweek and post-weekend serum phosphate levels and their target ranges associated with the lowest mortality risk differ. Thus, clinical guidelines should consider the timing of blood withdrawal when recommending optimal target ranges for serum phosphate and therapeutic strategies for phosphate control.

The effect of high-volume online haemodiafiltration on nutritional status and body composition: the ProtEin Stores prEservaTion (PESET) study.

Background: Compared with conventional haemodialysis (HD), online haemodiafiltration (OL-HDF) achieves a more efficient removal of uraemic toxins and reduces inflammation, which could favourably affect nutritional status. We evaluate the effect of OL-HDF on body composition and nutritional status in prevalent high-flux HD (HF-HD) patients. Methods: In all, 33 adults with chronic kidney disease (CKD) Stage 5 undergoing maintenance HF-HD were assigned to post-dilution OL-HDF (n = 17) or to remain on HF-HD (n = 16, control group) for 12 months. The primary outcome was the change in lean tissue mass (LTM), intracellular water (ICW) and body cell mass (BCM) assessed by multifrequency bioimpedance spectroscopy (BIS) at baseline and 4, 8 and 12 months. The rate of change in these parameters was estimated with linear mixed-effects models. Results: Compared with OL-HDF, patients assigned to HF-HD experienced a gradual reduction in LTM, ICW and BCM. These differences reached statistical significance at Month 12, with a relative difference of 7.31 kg [95% confidence interval (CI) 2.50-12.11; P = 0.003], 2.32 L (95% CI 0.63-4.01; P = 0.008) and 5.20 kg (95% CI 1.74-8.66; P = 0.004) for LTM, ICW and BCM, respectively. The normalized protein appearance increased in the OL-HDF group compared with the HF-HD group [0.26 g/kg/day (95% CI 0.05-0.47); P = 0.002], with a relative reduction in high-sensitive C-reactive protein [-13.31 mg/dL (95% CI -24.63 to -1.98); P = 0.02] at Month 12. Conclusions: OL-HDF for 1 year compared with HF-HD preserved muscle mass, increased protein intake and reduced the inflammatory state related to uraemia and dialysis, supporting the hypothesis that high convection volume can benefit nutritional status and prevent protein-energy wasting in HD patients.

Tenofovir-induced toxicity in renal proximal tubular epithelial cells: involvement of mitochondria.

OBJECTIVE: In-vivo studies suggest that mitochondria is involved in tenofovir (TFV)-induced renal toxicity, but the underlying mechanisms are still unclear. The aim of the present study was to assess the effects of TFV and its prodrug, TFV disoproxil fumarate, on mitochondrial function and cell survival/viability in a renal proximal tubular cell line. DESIGN AND METHODS: We evaluated parameters of cellular proliferation/survival (cell count, cell cycle, viability) and mitochondrial function (oxygen consumption, mitochondrial membrane potential, reactive oxygen species production) in NRK-52E cells. Intracellular TFV was measured by HPLC and expression of antioxidant genes was analysed by real-time PCR. RESULTS: Similar intracellular levels of TFV were reached with lower concentrations of the prodrug than of the drug, and correlated directly with a decrease in cell number. Both compounds inhibited proliferation and compromised mitochondrial function by decreasing mitochondrial membrane potential and increasing oxygen consumption and mitochondrial superoxide production. Altered oxidative status was confirmed by the overexpression of antioxidant genes. CONCLUSIONS: Intracellular accumulation of TFV induces mitochondrial toxicity in an in-vitro renal model and alters cell proliferation and viability. Our findings call for caution regarding the use of this nucleotide analogue reverse transcriptase inhibitor in patients with other risk factors that compromise mitochondrial function in the kidney.

Factors influencing pathological ankle-brachial index values along the chronic kidney disease spectrum: the NEFRONA study.

Background: The ankle-brachial index (ABI) is widely used to diagnose subclinical peripheral artery disease (PAD) in the general population, but data assessing its prevalence and related factors in different chronic kidney disease (CKD) stages are scarce. The aim of this study is to evaluate the prevalence and associated factors of pathological ABI values in CKD patients. Methods: NEFRONA is a multicentre prospective project that included 2445 CKD patients from 81 centres and 559 non-CKD subjects from 9 primary care centres across Spain. A trained team collected clinical and laboratory data, performed vascular ultrasounds and measured the ABI. Results: PAD prevalence was higher in CKD than in controls (28.0 versus 12.3%, P < 0.001). Prevalence increased in more advanced CKD stages, due to more patients with an ABI ≥1.4, rather than ≤0.9. Diabetes was the only factor predicting both pathological values in all CKD stages. Age, female sex, carotid plaques, higher carotid intima-media thickness, higher high-sensitivity C-reactive protein (hsCRP) and triglycerides, and lower 25-hydroxi-vitamin D were independently associated with an ABI ≤0.9. Higher phosphate and hsCRP, lower low-density lipoprotein (LDL)-cholesterol and dialysis were associated with an ABI ≥1.4. A stratified analysis showed different associated factors in each CKD stage, with phosphate being especially important in earlier CKD, and LDL-cholesterol being an independent predictor only in Sage 5D CKD. Conclusions: Asymptomatic PAD is very prevalent in all CKD stages, but factors related to a low or high pathological ABI differ, revealing different pathogenic pathways. Diabetes, dyslipidaemia, inflammation and mineral-bone disorders play a role in the appearance of PAD in CKD.

Regression of vascular calcification in a parathyroidectomized patient on dialysis with untreated hypocalcemia over 12-year follow-up
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Although some experimental targets involved in calcium deposition are emerging, no intervention has been described to reliably reverse vascular calcification (VC). We report a case of severe VC regression in a parathyroidectomized patient on hemodialysis over 12-year follow-up, highlighting the use of calcium-free phosphate binders and a 2.5 mEq/L calcium dialysate for reducing calcium loading, despite persistent asymptomatic hypocalcemia occurrences. This case suggests that phosphate-binder choice and calcium dialysate concentration could be influenced by other components of CKD-MBD besides biochemical parameters, such as the presence of VC, so concluding that asymptomatic hypocalcemia may not be as harmful as once supposed, and conferring greater prognostic weight to the presence of VC than to calcium levels.
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What is the optimal level of vitamin D in non-dialysis chronic kidney disease population?

AIM: To evaluate thresholds for serum 25(OH)D concentrations in relation to death, kidney progression and hospitalization in non-dialysis chronic kidney disease (CKD) population. METHODS: Four hundred and seventy non-dialysis 3-5 stage CKD patients participating in OSERCE-2 study, a prospective, multicenter, cohort study, were prospectively evaluated and categorized into 3 groups according to 25(OH)D levels at enrollment (less than 20 ng/mL, between 20 and 29 ng/mL, and at or above 30 ng/mL), considering 25(OH)D between 20 and 29 ng/mL as reference group. Association between 25(OH)D levels and death (primary outcome), and time to first hospitalization and renal progression (secondary outcomes) over a 3-year follow-up, were assessed by Kaplan-Meier survival curves and Cox-proportional hazard models. To identify 25(OH)D levels at highest risk for outcomes, receiver operating characteristic (ROC) curves were performed. RESULTS: Over 29 ± 12 mo of follow-up, 46 (10%) patients dead, 156 (33%) showed kidney progression, and 126 (27%) were hospitalized. After multivariate adjustment, 25(OH)D < 20 ng/mL was an independent predictor of all-cause mortality (HR = 2.33; 95%CI: 1.10-4.91; P = 0.027) and kidney progression (HR = 2.46; 95%CI: 1.63-3.71; P < 0.001), whereas the group with 25(OH)D at or above 30 ng/mL did not have a different hazard for outcomes from the reference group. Hospitalization outcomes were predicted by 25(OH) levels (HR = 0.98; 95%CI: 0.96-1.00; P = 0.027) in the unadjusted Cox proportional hazards model, but not after multivariate adjusting. ROC curves identified 25(OH)D levels at highest risk for death, kidney progression, and hospitalization, at 17.4 ng/mL [area under the curve (AUC) = 0.60; 95%CI: 0.52-0.69; P = 0.027], 18.6 ng/mL (AUC = 0.65; 95%CI: 0.60-0.71; P < 0.001), and 19.0 ng/mL (AUC = 0.56; 95%CI: 0.50-0.62; P = 0.048), respectively. CONCLUSION: 25(OH)D < 20 ng/mL was an independent predictor of death and progression in patients with stage 3-5 CKD, with no additional benefits when patients reached the levels at or above 30 ng/mL suggested as optimal by CKD guidelines.

Vascular calcification in patients with nondialysis CKD over 3 years.

BACKGROUND AND OBJECTIVES: Vascular calcification (VC) is common in CKD, but little is known about its prognostic effect on patients with nondialysis CKD. The prevalence of VC and its ability to predict death, time to hospitalization, and renal progression were assessed. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The Study of Mineral and Bone Disorders in CKD in Spain is a prospective, observational, 3-year follow-up study of 742 patients with nondialysis CKD stages 3-5 from 39 centers in Spain from April to May 2009. VC was assessed using Adragao (AS; x-ray pelvis and hands) and Kauppila (KS; x-ray lateral lumbar spine) scores from 572 and 568 patients, respectively. The primary end point was death. Secondary outcomes were hospital admissions and appearance of a combined renal end point (beginning of dialysis or drop >30% in eGFR). Factors related to VC were assessed by logistic regression analysis. Survival analysis was assessed by Cox proportional models. RESULTS: VC was present in 79% of patients and prominent in 47% (AS≥3 or KS>6). Age (odds ratio [OR], 1.05; 95% confidence interval [95% CI], 1.02 to 1.07; P<0.001), phosphorous (OR, 1.68; 95% CI, 1.28 to 2.20; P<0.001), and diabetes (OR, 2.11; 95% CI, 1.32 to 3.35; P=0.002) were independently related to AS≥3. After a median follow-up of 35 months (interquartile range=17-36), there were 70 deaths (10%). After multivariate adjustment for age, smoking, diabetes, comorbidity, renal function, and level of phosphorous, AS≥3 but not KS>6 was independently associated with all-cause (hazard ratio [HR], 2.07; 95% CI, 1.07 to 4.01; P=0.03) and cardiovascular (HR, 3.46; 95% CI, 1.27 to 9.45; P=0.02) mortality as well as a shorter hospitalization event-free period (HR, 1.14; 95% CI, 1.06 to 1.22; P<0.001). VC did not predict renal progression. CONCLUSIONS: VC is highly prevalent in patients with CKD. VC assessment using AS independently predicts death and time to hospitalization. Therefore, it could be a useful index to identify patients with CKD at high risk of death and morbidity as previously reported in patients on dialysis.