Influence of chronic kidney disease on cardiac structure and function

Advanced glycation end-products, cardiac function and heart failure in the general population: The Rotterdam Study

AIMS/HYPOTHESIS

The aim of this work was to assess the association of advanced glycation end-products (AGEs), measured by skin autofluorescence (SAF), with prevalent heart failure, and with systolic and diastolic cardiac function, in a large population-based cohort study.

METHODS

We assessed the cross-sectional association between SAF and prevalent heart failure among 2426 participants from the population-based Rotterdam Study, using logistic regression. Next, among individuals free of heart failure (N=2362), we examined the link between SAF (on a continuous scale) and echocardiographic parameters of left ventricular (LV) systolic and diastolic function using linear regressions. Analyses were adjusted for traditional cardiovascular risk factors.

RESULTS

Higher levels of SAF were associated with higher odds of prevalent heart failure (multivariable adjusted OR 2.90 [95% CI 1.80, 4.62] for one unit higher SAF value). Among individuals without heart failure, one unit increase in SAF was associated with 0.98% lower LV ejection fraction (mean difference [β] -0.98% [95% CI -1.45%, -0.50%]). The association was stronger among participants with diabetes (β -1.84% [95% CI -3.10%, -0.58%] and β -0.78% [95% CI -1.29%, -0.27%] among participants with and without diabetes, respectively). Associations of SAF with diastolic function parameters were not apparent, except in men with diabetes.

CONCLUSIONS/INTERPRETATION

AGE accumulation was independently associated with prevalent heart failure. Among individuals free of heart failure, AGEs were associated with cardiac function, in particular systolic function. This association was present in participants with and without diabetes and was more prominent in those with diabetes.

Associations between Albuminuria, Estimated GFR and Cardiac Phenotype in a Cohort with Chronic Kidney Disease - The CPH-CKD ECHO Study

OBJECTIVE

Echocardiographic findings in chronic kidney disease (CKD) vary. We sought to estimate the prevalence of abnormal cardiac structure and function in patients with CKD and their association to estimated glomerular filtration rate (eGFR) and urine albumin/creatinine ratio (UACR).

METHODS

We prospectively enrolled 825 outpatients with non-dialysis-dependent CKD, mean age 58± 13 yrs, and 175 matched healthy controls, mean age 60±12 yrs. Echocardiography included assessment of left ventricular (LV) hypertrophy, LV ejection fraction (LVEF), global longitudinal strain (GLS) and diastolic dysfunction according to ASE/EACVI guidelines.

RESULTS

LV hypertrophy was found in 9% of patients vs. 1.7% of controls (p=0.005) was independently associated with UACR (p=0.002). Median LVEF was 59.4% (IQR 55.2, 62.8) in patients vs. 60.8% (57.7, 64.1) in controls (p=0.002). GLS was decreased in patients with eGFR <60ml/min/1.73m² (-17.6%±3.1%) vs. patients with higher eGFR (19.0%±2.2%, p<0.001), who were similar to controls. . Diastolic dysfunction was detected in 55% of patients and in 34% of controls.

LIMITATIONS

Non-random sampling, cross-sectional analysis.

CONCLUSIONS

We report lower prevalence of hypertrophy than previous studies, but similar measurements of systolic and diastolic function. Cardiac remodeling in CKD may be influenced by treatment modalities, demographics, comorbidities and renal pathology.

Epidemiology of cardiovascular death in kidney failure: An Australian and New Zealand cohort study using data linkage

Aim

Cardiovascular mortality risk evolves over the lifespan of kidney failure (KF), as patients develop comorbid disease and transition between treatment modalities. Absolute cardiovascular death rates would help inform clinical practice and health‐care provision, but are not well understood across a continuum of dialysis and transplant states. We aimed to characterize cardiovascular death across the natural history of KF using a lifespan approach.

Methods

We performed a population‐based cohort study of incident patients commencing kidney replacement therapy in Australia and New Zealand. Cardiovascular deaths were identified using data linkage to national death registers. We estimated the probability of death and kidney transplant using multi‐state models, and calculated rates of graft failure and cardiovascular death across demographic factors and comorbidities.

Results

Among 60 823 incident patients followed over 381 874 person‐years, 25% (8492) of deaths were from cardiovascular disease. At 15 years from treatment initiation, patients had a 15.2% probability of cardiovascular death without being transplanted, but only 2.3% probability of cardiovascular death post‐transplant. Females had a 3% lower probability of cardiovascular death at 15 years (15.3% vs. 18.6%) but 4% higher probability of non‐cardiovascular death (54.5% vs. 50.8%). Within the first year of dialysis, cardiovascular mortality peaked in the second month and showed little improvement across treatment era.

Conclusion

Despite improvements over time, cardiovascular death remains common in KF, particularly among the dialysis population and in the first few months of treatment. Multi‐state models can provide absolute measures of cardiovascular mortality across both dialysis and transplant states.

In this population‐based cohort study using multi‐state models (alive without kidney transplant [KT], CV death without KT, non‐CV death without KT, alive after first KT, CV death after first KT and non‐CV death after first KT), the probability of CV death was higher in non‐KT than KT patients at 15 years from treatment. In patients on dialysis, CV mortality was highest from the second month after commencing dialysis and remained high thereafter. Thus, the use of multi‐state models provides helpful information on impacts of different treatments with respect to serious outcomes.

Fibrosis, the Bad Actor in Cardiorenal Syndromes: Mechanisms Involved

Cardiorenal syndrome is a term that defines the complex bidirectional nature of the interaction between cardiac and renal disease. It is well established that patients with kidney disease have higher incidence of cardiovascular comorbidities and that renal dysfunction is a significant threat to the prognosis of patients with cardiac disease. Fibrosis is a common characteristic of organ injury progression that has been proposed not only as a marker but also as an important driver of the pathophysiology of cardiorenal syndromes. Due to the relevance of fibrosis, its study might give insight into the mechanisms and targets that could potentially be modulated to prevent fibrosis development. The aim of this review was to summarize some of the pathophysiological pathways involved in the fibrotic damage seen in cardiorenal syndromes, such as inflammation, oxidative stress and endoplasmic reticulum stress, which are known to be triggers and mediators of fibrosis.

Glomerular Filtration Dysfunction is Associated with Cardiac Adverse Remodeling in Menopausal Diabetic Chinese Women

Background

Previous studies have showed that nephropathy was associated with cardiac structural changes and dysfunction among diabetic adults. However, information on the association of glomerular filtration dysfunction with the cardiac adverse remodeling is still limited in menopausal diabetic women. Therefore, we investigated whether impaired glomerular filtration function is associated with the cardiac adverse remodeling in menopausal Chinese women with type 2 diabetes mellitus (DM).

Methods

A total of 1231 hospitalized menopausal Chinese women with type 2 DM were collected retrospectively. The cross-sectional data of echocardiography were compared among estimated glomerular filtration rate (eGFR) categorized groups.

Results

In menopausal diabetic women, moderate to severe glomerular filtration dysfunction (eGFR <60 mL/min per 1.73m²) was found to be associated with enlarged left-side atrioventricular chambers, increased ventricular wall thickness, decreased cardiac function and dilated right ventricle (All P < 0.05).

Conclusion

Glomerular filtration dysfunction is associated with cardiac adverse structural remodeling and dysfunction in menopausal Chinese women with type 2 DM.

Cardiac Imaging for Coronary Heart Disease Risk Stratification in Chronic Kidney Disease

Chronic kidney disease (CKD), defined as dysfunction of the glomerular filtration apparatus, is an independent risk factor for the development of coronary artery disease (CAD). Patients with CKD are at a substantially higher risk of cardiovascular mortality compared with the age- and sex-adjusted general population with normal kidney function. The risk of CAD and mortality in patients with CKD is correlated with the degree of renal dysfunction including presence of microalbuminuria. A greater cardiovascular risk, albeit lower than for patients receiving dialysis, persists even after kidney transplantation. Congestive heart failure, commonly caused by CAD, also accounts for a significant portion of the cardiovascular-related events observed in CKD. The optimal strategy for the evaluation of CAD in patients with CKD, particularly before renal transplantation, remains a topic of contention spanning over several decades. Although the evaluation of coexisting cardiac disease in patients with CKD is desirable, severe renal dysfunction limits the use of radiographic and magnetic resonance contrast agents due to concerns regarding contrast-induced nephropathy and nephrogenic systemic sclerosis, respectively. In addition, many patients with CKD have extensive and premature (often medial) calcification disproportionate to the severity of obstructive CAD, thereby limiting the diagnostic value of computed tomography angiography. As such, echocardiography, non-contrast-enhanced magnetic resonance, nuclear myocardial perfusion, and metabolic imaging offer a variety of approaches to assess obstructive CAD and cardiomyopathy of advanced CKD without the need for nephrotoxic contrast agents.

Association Between High-Sensitivity Cardiac Troponin T and Echocardiographic Parameters in Chronic Kidney Disease: Results From the KNOW-CKD Cohort Study

Background

It is unclear whether high‐sensitivity troponin T (hs‐TnT) is associated with subclinical cardiac changes in chronic kidney disease (CKD). We evaluated the relationship between hs‐TnT and left ventricular structure and function in a CKD population, according to estimated glomerular filtration rate.

Methods and Results

We analyzed 2017 patients with CKD stages 1 to 5 (predialysis) in the KNOW‐CKD (Korean Cohort Study for Outcome in Patients With Chronic Kidney Disease) cohort. The predictor was hs‐TnT level measured at baseline, and the outcomes were left ventricular hypertrophy (LVH) and systolic and diastolic dysfunction shown by echocardiography at baseline and after 4 years. Participants were categorized into quartiles according to hs‐TnT levels. The associations between quartiles of hs‐TnT and outcomes were assessed using multivariable logistic regression analysis with confounders including demographics, medical history, and laboratory findings. A receiver operating characteristic curve was used to assess the diagnostic power of hs‐TnT for the outcomes as a continuous variable. For subgroup analysis, patients were stratified based on an estimated glomerular filtration rate of 60 mL/min per 1.73 m². Elevated hs‐TnT was associated with LVH and diastolic dysfunction at baseline in an adjusted model but was not associated with systolic dysfunction. These associations remained significant for both estimated glomerular filtration rate subgroups. Receiver operating characteristic curve analysis showed that hs‐TnT as a continuous variable exhibited fair significance for detection of LVH (area under the curve: 0.689) and diastolic dysfunction (area under the curve: 0.744). Multivariable analysis showed that higher hs‐TnT levels at baseline were related to development of LVH but not diastolic dysfunction (n=864).

Conclusions

In CKD patients, hs‐TnT is strongly associated with alterations of left ventricular structure and diastolic dysfunction for both estimated glomerular filtration rate strata. Baseline hs‐TnT levels are predictive of new LVH on follow‐up.

Trends in Hospitalizations and Survival of Acute Decompensated Heart Failure in Four US Communities (2005-2014): ARIC Study Community Surveillance

BACKGROUND

Community trends of acute decompensated heart failure (ADHF) in diverse populations may differ by race and sex.

METHODS

The ARIC study (Atherosclerosis Risk in Communities) sampled heart failure-related hospitalizations (≥55 years of age) in 4 US communities from 2005 to 2014 using International Classification of Diseases, Ninth Revision, Clinical Modification codes. ADHF hospitalizations were validated by standardized physician review and computer algorithm, yielding 40 173 events after accounting for sampling design (unweighted n=8746).

RESULTS

Of the ADHF hospitalizations, 50% had reduced ejection fraction, and 39% had preserved EF (HFpEF). HF with reduced ejection fraction was more common in black men and white men, whereas HFpEF was most common in white women. Average age-adjusted rates of ADHF were highest in blacks (38.1 per 1000 black men, 30.5 per 1000 black women), with rates differing by HF type and sex. ADHF rates increased over the 10 years (average annual percentage change: black women +4.3%, black men +3.7%, white women +1.9%, white men +2.6%), mostly reflecting more acute HFpEF. Age-adjusted 28-day and 1-year case fatality proportions were ≈10% and 30%, respectively, similar across race-sex groups and HF types. Only blacks showed decreased 1-year mortality over time (average annual percentage change: black women -5.4%, black men -4.6%), with rates differing by HF type (average annual percentage change: black women HFpEF -7.1%, black men HF with reduced ejection fraction -4.7%).

CONCLUSIONS

Between 2005 and 2014, trends in ADHF hospitalizations increased in 4 US communities, primarily driven by acute HFpEF. Survival at 1 year was poor regardless of EF but improved over time for black women and black men.

Nutrition education in the care of patients with chronic kidney disease and end-stage renal disease

Diet counseling and nutrition education are recommended in the prevention and management of chronic kidney disease (CKD) and end-stage renal disease (ESRD). The importance of effectively addressing nutrition with patients has grown given the increasing prevalence of obesity, hypertension, and diabetes; conditions which influence CKD/ESRD. Dietary advice for individuals with CKD/ESRD can be seen as complex; and successful dietary management requires careful planning, periodic assessment of nutritional status, as well as monitoring of dietary compliance. In spite of recommendations and pressing need, formal training in nutrition and adequate preparation for providers is limited; and for physicians the lack of nutrition education has been acknowledged, repeatedly, as an area for improvement in medical training curricula. It has also been suggested that dietitians have an essential role in management of CKD in the primary care setting; however, dietitians who do not practice renal education daily may need training on the specific challenges in CKD/ESRD. The objectives of this chapter were to: characterize select nutrition education resources for providers who care for patients with CKD/ESRD; summarize key dietary components emphasized in the care of patients with CKD/ESRD; and address practical considerations in educational efforts focused on nutrition and CKD/ESRD.

Kidney Disease Measures and Left Ventricular Structure and Function: The Atherosclerosis Risk in Communities Study

Background

Heart failure is one of the most important complications of chronic kidney disease (CKD). However, few studies comprehensively investigated left ventricular (LV) structure and function in relation to 2 key CKD measures, estimated glomerular filtration rate (eGFR) and urine albumin/creatinine ratio (ACR).

Methods and Results

Among 4175 ARIC (Atherosclerosis Risk in Communities) participants (aged 66–90 years during 2011–2013), we quantified the association of eGFR and ACR with echocardiogram parameters of LV mass, size, systolic function, and diastolic function. Adjusting for demographic variables, both CKD measures were significantly associated with most echocardiogram parameters. Additionally accounting for other potential confounders, we observed significantly higher LV mass index according to reduced eGFR (82.3 [95% confidence interval (CI), 77.6–87.0] g/m² for eGFR <30 mL/min per 1.73 m², 80.9 [95% CI, 77.3–84.6] g/m² for eGFR 30–44 mL/min per 1.73 m², and 80.1 [95% CI, 76.7–83.5] g/m² for eGFR 45–59 mL/min per 1.73 m² compared with 78.7 [95% CI, 75.3–82.1] g/m² for eGFR 75–89 mL/min per 1.73 m²; trend P<0.001). Regarding LV size and function, significant differences were observed for some parameters, particularly at eGFR <30 mL/min per 1.73 m². For ACR, the associations remained significant for most parameters (eg, LV mass index, 91.5 [95% CI, 86.6–96.5] g/m² for ACR ≥300 mg/g and 82.9 [95% CI, 79.4–86.3] g/m² for ACR 30–299 mg/g compared with 77.7 [95% CI, 74.4–81.1] g/m² for ACR <10 mg/g [trend P<0.001]; left arterial volume index, 24.9 [95% CI, 22.9–26.8] and 24.7 [95% CI, 23.4–26.1] mL/m² compared with 23.4 [95% CI, 22.1–24.7] mL/m², respectively [trend P=0.010]). Dichotomizing echo parameters with clinical thresholds, the stronger relationships of ACR over eGFR were further evident.

Conclusions

LV mass was related to both CKD measures, whereas LV size and function were robustly associated with albuminuria. These results have implications for pathophysiological processes behind cardiorenal syndrome and targeted cardiac assessment in patients with CKD.

Association of Albuminuria With Cardiac Dysfunction in US Hispanics/Latinos

Higher urine albumin-to-creatinine ratio (UACR) has been associated with cardiac dysfunction in the general population. We assessed the association of UACR with cardiac structure and function in the Echocardiographic Study of Latinos (Echo-SOL), an ancillary study of the Hispanic Community Health Study/Study of Latinos across 4 US sites. Echo-SOL participants underwent standard 2-dimensional echocardiography, including speckle-tracking strain analysis. UACR was categorized as normal and high-normal (based on the midpoint of values below microalbuminuria), microalbuminuria (≥17 mg/g for men; ≥25 mg/g for women), and macroalbuminuria (≥250 mg/g; ≥355 mg/g). Simultaneous assessments were made of left ventricular (LV) mass index and hypertrophy and measures of LV systolic and diastolic dysfunction. We assessed the association of UACR with subclinical cardiac measures, adjusting for sociodemographic and cardiometabolic factors. Among 1,815 participants (median age 54, women 65%), 42% had normal UACR, 43% high-normal UACR, 13% microalbuminuria, and 2% macroalbuminuria. Prevalence of LV hypertrophy was 13%, LV systolic dysfunction (ejection fraction <50%) 3%, and diastolic dysfunction 53%. After covariate adjustment, both micro- and macroalbuminuria were significantly associated with a twofold increase in LV hypertrophy. Microalbuminuria but not macroalbuminuria was associated with worse global longitudinal strain. Elevated UACR, even at high-normal levels, was significantly associated with greater diastolic dysfunction. In conclusion, elevated UACR was associated with LV hypertrophy and diastolic dysfunction in the largest known population sample of US Hispanic/Latinos. Screening and detection of even high-normal UACR could be of value to guide cardiovascular disease prevention efforts among Hispanic/Latino Americans.

The association of chronic kidney disease and microalbuminuria with heart failure with preserved vs. reduced ejection fraction

AIMS

Chronic kidney disease (CKD) and microalbuminuria are associated with incident heart failure (HF), but their relative contributions to HF with preserved vs. reduced EF (HFpEF and HFrEF) are unknown. We sought to evaluate the associations of CKD and microalbuminuria with incident HF subtypes in the community-based Framingham Heart Study (FHS).

METHODS AND RESULTS

We defined CKD as glomerular filtration rate <60 mL/min/1.73 m² , and microalbuminuria as a urine albumin to creatinine ratio (UACR) ≥17 mg/g in men and ≥25 mg/g in women. We observed 754 HF events (324 HFpEF/326 HFrEF/104 unclassified) among 9889 FHS participants with serum creatinine measured (follow-up 13 ± 4 years). In Cox models adjusted for clinical risk factors, CKD (prevalence = 9%) was associated with overall HF [hazard ratio (HR) 1.24, 95% confidence interval (CI) 1.01-1.51], but was not significantly associated with individual HF subtypes. Among 2912 individuals with available UACR (follow-up 15 ± 4 years), 192 HF events (91 HFpEF/93 HFrEF/8 unclassified) occurred. Microalbuminuria (prevalence = 17%) was associated with a higher risk of overall HF (HR 1.71, 95% CI 1.25-2.34) and HFrEF (HR 2.10, 95% CI 1.35-3.26), but not HFpEF (HR 1.26, 95% CI 0.78-2.03). In cross-sectional analyses, microalbuminuria was associated with LV systolic dysfunction (odds ratio 3.19, 95% CI 1.67-6.09).

CONCLUSIONS

Microalbuminuria was associated with incident HFrEF prospectively, and with LV systolic dysfunction cross-sectionally in a community-based sample. In contrast, CKD was modestly associated with overall HF but not differentially associated with HFpEF vs. HFrEF. The mechanisms responsible for the relationship of microalbuminuria to future development of HFrEF warrant further investigation.

Metabolomics Identifies Multiple Candidate Biomarkers to Diagnose and Stage Human African Trypanosomiasis

Treatment for human African trypanosomiasis is dependent on the species of trypanosome causing the disease and the stage of the disease (stage 1 defined by parasites being present in blood and lymphatics whilst for stage 2, parasites are found beyond the blood-brain barrier in the cerebrospinal fluid (CSF)). Currently, staging relies upon detecting the very low number of parasites or elevated white blood cell numbers in CSF. Improved staging is desirable, as is the elimination of the need for lumbar puncture. Here we use metabolomics to probe samples of CSF, plasma and urine from 40 Angolan patients infected with Trypanosoma brucei gambiense, at different disease stages. Urine samples provided no robust markers indicative of infection or stage of infection due to inherent variability in urine concentrations. Biomarkers in CSF were able to distinguish patients at stage 1 or advanced stage 2 with absolute specificity. Eleven metabolites clearly distinguished the stage in most patients and two of these (neopterin and 5-hydroxytryptophan) showed 100% specificity and sensitivity between our stage 1 and advanced stage 2 samples. Neopterin is an inflammatory biomarker previously shown in CSF of stage 2 but not stage 1 patients. 5-hydroxytryptophan is an important metabolite in the serotonin synthetic pathway, the key pathway in determining somnolence, thus offering a possible link to the eponymous symptoms of “sleeping sickness”. Plasma also yielded several biomarkers clearly indicative of the presence (87% sensitivity and 95% specificity) and stage of disease (92% sensitivity and 81% specificity). A logistic regression model including these metabolites showed clear separation of patients being either at stage 1 or advanced stage 2 or indeed diseased (both stages) versus control.

Human African trypanosomiasis, also known as sleeping sickness, is a parasitic disease that affects people in sub-Saharan Africa. There are two stages of the infection. The first stage involves parasites proliferating in the bloodstream following introduction via the bite of an infected tsetse fly. The second, more serious stage, involves parasite invasion and proliferation within the central nervous system causing characteristic disturbances to the patients’ sleep wake patterns and progressive appearance of other neurological signs, including walking disabilities behaviour changes, abnormal movements, incontinence, then ultimately coma and death. Drugs are available to treat both stages of the disease, but the drugs for stage 2 disease have serious side effects and must be administered in hospital settings. Stage determination is thus a key element for disease management. Currently staging involves microscopic evaluation of CSF following a lumbar puncture. Here, we have analysed the metabolome of CSF, blood and urine of patients to seek biomarkers to stage the disease based on these biofluids. CSF and blood fluids were found to have distinctive metabolic biomarkers and when several of these metabolites are combined, a sensitive and robust discriminatory staging test can be developed. Some CSF metabolic markers relate to brain inflammation, whilst others may be related to somnolence associated with the disease in stage 2 patients, which may also help in understanding disease progression. Interestingly, distinctive biomarkers were also found in plasma, potentially abrogating the need for diagnostic lumbar punctures in the future.

Effects of mineralocorticoid receptor antagonists on left ventricular mass in chronic kidney disease patients: a systematic review and meta-analysis

BACKGROUND

Mineralocorticoid receptor antagonists (MRAs) are used widely in treatment of heart failure, but their effects on cardiovascular complications and mortality of chronic kidney disease (CKD) are not well known. Thus, we aim to assess such therapeutic effects of MRAs on CKD.

METHODS

Electronic literature published in any language until Dec 31, 2015, was systematically searched on PubMed, Embase, and Cochrane Central Register of Controlled Trials. Primary outcome was left ventricular mass (LVM) or LVM index (LVMI), and secondary outcome was all-cause mortality and major adverse cardiovascular events (MACEs). Results of continuous outcomes were pooled using mean difference (MD) and standard mean difference (SMD). Risk ratios (RRs) with 95 % confidence intervals (CIs) were pooled using a random- or fixed-effects model.

RESULTS

Totally 12 studies (6 randomized controlled trials with 1003 participants) involving 4935 patients were included. MRA treatment versus non-MRA treatment resulted in a significant change of 0.93 SMD (standard mean difference) in LVM (LVMI), a significant reduction of 22 % in all-cause mortality, a significant reduction of incidence of MACEs (RR 0.65, P = 0.001), significantly higher prevalence rates of hyperkalemia (>5.5 mmol/L), but no significant change in prevalence rates of severe hyperkalemia (>6.0 mmol/L).

CONCLUSION

MRA benefits CKD patients in terms of LVMI, all-cause mortality, and MACEs with no incidence of severe hyperkalemia. Nevertheless, the real effects of MRAs on cardiovascular events and mortality as well as their safety in CKD patients should be identified by further studies with prospective and large-sample clinical trials.

Chronic Kidney Disease and the Risk of New-Onset Atrial Fibrillation: A Meta-Analysis of Prospective Cohort Studies

Objective

Recent epidemiological evidence indicates an association between chronic kidney disease (CKD) and the risk of new-onset atrial fibrillation (AF), but the results are inconclusive. This meta-analysis examined the association between CKD and new-onset AF.

Methods

PubMed, EMBASE, the Cochrane Collaboration and the reference lists of relevant articles were searched to identify eligible studies. The random effect model was used to calculate the overall multivariable-adjusted hazard ratio (HR) with its corresponding 95% confidence interval (CI). Associations were tested in subgroups of study characteristics and study quality criteria. We also performed sensitivity analyses and assessments of publishing bias.

Results

Seven prospective cohort studies (n = 400,189 participants) were included in this meta-analysis. Pooled results suggested that CKD was associated with an increased adjusted risk estimate for new-onset AF (HR, 1.47; 95% CI, 1.21–1.78), with significant heterogeneity between these studies (I² = 79.7%, P<0.001). Results were not different in any subgroup except sample size. Stratified analyses found that the diagnostic method of CKD and eGFR (estimated glomerular filtration rate), the number of confounders adjusted for, and study quality explained little of the variation between studies. Sensitivity analysis further demonstrated the results to be robust.

Conclusions

CKD is associated with an increased risk of incident AF. Further research is needed to investigate the biological association between CKD and AF and identify a preventive strategy to decrease the incidence of AF in CKD patients.

Extracellular purines' action on glomerular albumin permeability in isolated rat glomeruli: insights into the pathogenesis of albuminuria

Purinoceptors (adrengeric receptors and P2 receptors) are expressed on the cellular components of the glomerular filtration barrier, and their activation may affect glomerular permeability to albumin, which may ultimately lead to albuminuria, a well-established risk factor for the progression of chronic kidney disease and development of cardiovascular diseases. We investigated the mechanisms underlying the in vitro and in vivo purinergic actions on glomerular filter permeability to albumin by measuring convectional albumin permeability (Palb) in a single isolated rat glomerulus based on the video microscopy method. Primary cultured rat podocytes were used for the analysis of Palb, cGMP accumulation, PKG-Iα dimerization, and immunofluorescence. In vitro, natural nucleotides (ATP, ADP, UTP, and UDP) and nonmetabolized ATP analogs (2-meSATP and ATP-γ-S) increased Palb in a time- and concentration-dependent manner. The effects were dependent on P2 receptor activation, nitric oxide synthase, and cytoplasmic guanylate cyclase. ATP analogs significantly increased Palb, cGMP accumulation, and subcortical actin reorganization in a PKG-dependent but nondimer-mediated route in cultured podocytes. In vivo, 2-meSATP and ATP-γ-S increased Palb but did not significantly affect urinary albumin excretion. Both agonists enhanced the clathrin-mediated endocytosis of albumin in podocytes. A product of adenine nucleotides hydrolysis, adenosine, increased the permeability of the glomerular barrier via adrenergic receptors in a dependent and independent manner. Our results suggest that the extracellular nucleotides that stimulate an increase of glomerular Palb involve nitric oxide synthase and cytoplasmic guanylate cyclase with actin reorganization in podocytes.

Phosphate binders for the treatment of chronic kidney disease: role of iron oxyhydroxide

Chronic kidney disease-mineral bone disorder is frequent in patients with renal failure. It is characterized by abnormalities in mineral and bone metabolism with resulting hyperphosphatemia, low serum vitamin D, secondary hyperparathyroidism, altered bone morphology and strength, higher risk of bone fractures, and development of vascular or other soft tissue calcifications. Besides the recommendation to reduce phosphorus dietary intake, many drugs are currently available for the treatment of calcium/phosphate imbalance. Among them, phosphate binders represent a milestone. Calcium-based binders (calcium carbonate, calcium acetate) are effective in lowering serum phosphate, but their use has been associated with an increased risk of hypercalcemia and calcifications. Calcium-free binders (sevelamer hydrochloride, sevelamer carbonate, and lanthanum carbonate) are equally or slightly less effective than calcium-containing compounds. They would not induce an increase in calcium levels but may have relevant side effects, including gastrointestinal symptoms for sevelamer and risk of tissue accumulation for lanthanum. Accordingly, new phosphate binders are under investigation and some of them have already been approved. A promising option is sucroferric oxyhydroxide (Velphoro(®), PA21), an iron-based phosphate binder consisting of a mixture of polynuclear iron(III)-oxyhydroxide, sucrose, and starches. The present review is focused on pharmacology, mode of action, and pharmacokinetics of sucroferric oxyhydroxide, with a discussion on comparative efficacy, safety, and tolerability studies of this drug in chronic kidney disease and patient perspectives such as quality of life, satisfaction, and acceptability. Sucroferric oxyhydroxide has proven to be as effective as sevelamer in reducing phosphatemia with a similar safety profile and lower pill burden. Experimental and clinical studies have documented a minimal percentage of iron absorption without inducing toxicity. In conclusion, the overall benefit-risk balance of sucroferric oxyhydroxide is deemed to be positive, and this new drug may therefore represent a good alternative to traditional phosphate binders for the treatment of hyperphosphatemia in dialysis patients.