Benefits and harms of statin therapy for persons with chronic kidney disease: a systematic review and meta-analysis

Mechanisms and consequences of carbamoylation

Protein carbamoylation is a non-enzymatic post-translational modification that binds isocyanic acid, which can be derived from the dissociation of urea or from the myeloperoxidase-mediated catabolism of thiocyanate, to the free amino groups of a multitude of proteins. Although the term 'carbamoylation' is usually replaced by the term "carbamylation" in the literature, carbamylation refers to a different chemical reaction (the reversible interaction of CO₂ with α and ε-amino groups of proteins). Depending on the altered molecule (for example, collagen, erythropoietin, haemoglobin, low-density lipoprotein or high-density lipoprotein), carbamoylation can have different pathophysiological effects. Carbamoylated proteins have been linked to atherosclerosis, lipid metabolism, immune system dysfunction (such as inhibition of the classical complement pathway, inhibition of complement-dependent rituximab cytotoxicity, reduced oxidative neutrophil burst, and the formation of anti-carbamoylated protein antibodies) and renal fibrosis. In this Review, we discuss the carbamoylation process and evaluate the available biomarkers of carbamoylation (for example, homocitrulline, the percentage of carbamoylated albumin, carbamoylated haemoglobin, and carbamoylated low-density lipoprotein). We also discuss the relationship between carbamoylation and the occurrence of cardiovascular events and mortality in patients with chronic kidney disease and assess the effects of strategies to lower the carbamoylation load.

Vitamin D status and all-cause mortality in patients with chronic kidney disease: A systematic review and dose-response meta-analysis

CONTEXT

Prevalence of vitamin D deficiency is high in patients with chronic kidney disease. Less attention has been paid to measurement and correction of serum level of 25(OH)D in these patients.

OBJECTIVE

We examined the association between different levels of serum 25(OH)D and risk of all-cause mortality in patients with chronic kidney disease.

DATA SOURCES

Systematic search were done using MedLine and EMBASE from inception up to November 2016. Reference lists of all relevant articles and reviews also were searched.

STUDY SELECTION

Prospective or retrospective cohort studies that reported risk estimates of all-cause mortality for three or more categories of serum 25(OH)D in patients with chronic kidney disease were selected. Studies that reported results as continuously also were included. Two independent investigators screened and selected the articles. Of 1281 identified studies, 13 prospective cohorts, two retrospective cohorts and one nested case-control study with 17053 patients and 7517 incident death were included.

DATA EXTRACTION

Two independent authors extracted data from included studies. Any discrepancies were resolved through consensus.

DATA SYNTHESIS

Reported risk estimates were combined using a random-effects model. Summary risk estimates of all-cause mortality were1.63 (95%CI: 1.32, 1.94) for severe deficiency (<10 ng/ml), 1.22 (95%CI: 1.09, 1.35) for mild deficiency (10-20 ng/ml) and 1.12 (95%CI: 1.06, 1.18) for insufficiency (20-30 ng/ml). Results were more evident in dialysis dependent patients. 10 ng/ml increment in serum 25(OH)D was associated with 21% reduction in the risk of overall mortality (RR: 0.79, 95%CI: 0.70, 0.87).Lower risk of all-cause mortality was observed at serum 25(OH)D about 25 to 30 ng/ml. Dialysis treatment was one of the sources of variation between studies.

CONCLUSIONS

Higher levels of serum 25(OH) D were associated with lower risk of all-cause mortality in patients with chronic kidney disease, but concerning serum levels more than 35 ng/mL we have no conclusive evidence.

Erythropoietin Hyporesponsiveness in Dialysis Patients: Possible Role of Statins

BACKGROUND

Hypothesizing that statins may be useful as adjuvant treatment for renal anemia, we examined the association between statin prescription (Rx) and erythropoiesis-stimulating agent (ESA) hyporesponsiveness in Japanese hemodialysis (HD) patients prescribed ESAs.

METHODS

We examined 3,602 patients in 60 HD facilities dialyzed 3 times/week for ≥4 months from the Japan Dialysis Outcomes and Practice Patterns Study phases 3-5 (2005-2015). Statin Rx was reported at the end of a 4-month interval (baseline) for each patient. ESA hyporesponsiveness in the subsequent 4 months was then defined as a binary indicator (mean hemoglobin [Hgb] level <10 g/dL and mean ESA dose >6,000 units/week) and separately as the ESA resistance index (ERI; mean ESA dose/[dry weight × mean Hgb]). We used adjusted logistic and linear regressions to evaluate the associations between statin Rx and ESA hyporesponsiveness.

RESULTS

At baseline, 16.2% of patients reported statin Rx; 12.8% were classified as having ESA hyporesponsiveness during 4 months of follow-up. Compared to patients without statin Rx, patients with statin Rx had lower odds of ESA hyporesponsiveness (OR 0.87; 95% CI 0.66-1.15). Similarly, the ERI was lower for those with statin Rx than without (ratio of means, 0.94; 95% CI 0.89-0.99) after adjustment for possible confounders.

CONCLUSIONS

Our results suggest that statins may slightly reduce ESA hyporesponsiveness in HD patients. However, any causal inference is limited by the observational study design and unmeasured compliance with statin Rx.

Periodontitis and early mortality among adults treated with hemodialysis: a multinational propensity-matched cohort study

BACKGROUND

Periodontitis is associated with cardiovascular mortality in the general population and adults with chronic diseases. However, it is unclear whether periodontitis predicts survival in the setting of kidney failure.

METHODS

ORAL-D was a propensity matched analysis in 3338 dentate adults with end-stage kidney disease treated in a hemodialysis network in Europe and South America designed to examine the association between periodontitis and all-cause and cardiovascular-related mortality in people on long-term hemodialysis. Participants were matched 1:1 on their propensity score for moderate to severe periodontitis assessed using the World Health Organization Community Periodontal Index. A random-effects Cox proportional hazards model was fitted with shared frailty to account for clustering of mortality risk within countries.

RESULTS

Among the 3338 dentate participants, 1355 (40.6%) had moderate to severe periodontitis at baseline. After using propensity score methods to generate a matched cohort of participants with periodontitis similar to those with none or mild periodontal disease, moderate to severe periodontitis was associated with a lower risk of all-cause (9.1 versus 13.0 per 100 person years, hazard ratio 0.74, 95% confidence interval 0.61 to 0.90) and cardiovascular (4.3 versus 6.9 per 100 person years, hazard ratio 0.67, 0.51 to 0.88) mortality. These associations were not changed substantially when participants were limited to those with 12 or more natural teeth and when accounting for competing causes of cardiovascular death.

CONCLUSION

In contrast to the general population, periodontitis does not appear to be associated with an increased risk of early death in adults treated with hemodialysis.

The importance of accurate measurement of aortic stiffness in patients with chronic kidney disease and end-stage renal disease

Cardiovascular (CV) disease is the leading cause of death in chronic kidney disease (CKD) and end-stage renal disease (ESRD). A key driver in this pathology is increased aortic stiffness, which is a strong, independent predictor of CV mortality in this population. Aortic stiffening is a potentially modifiable biomarker of CV dysfunction and in risk stratification for patients with CKD and ESRD. Previous work has suggested that therapeutic modification of aortic stiffness may ameliorate CV mortality. Nevertheless, future clinical implementation relies on the ability to accurately and reliably quantify stiffness in renal disease. Pulse wave velocity (PWV) is an indirect measure of stiffness and is the accepted standard for non-invasive assessment of aortic stiffness. It has typically been measured using techniques such as applanation tonometry, which is easy to use but hindered by issues such as the inability to visualize the aorta. Advances in cardiac magnetic resonance imaging now allow direct measurement of stiffness, using aortic distensibility, in addition to PWV. These techniques allow measurement of aortic stiffness locally and are obtainable as part of a comprehensive, multiparametric CV assessment. The evidence cannot yet provide a definitive answer regarding which technique or parameter can be considered superior. This review discusses the advantages and limitations of non-invasive methods that have been used to assess aortic stiffness, the key studies that have assessed aortic stiffness in patients with renal disease and why these tools should be standardized for use in clinical trial work.

Rationale for the use of statins in liver disease

The evolution of chronic liver injuries from benign and manageable dysfunction to life threatening end-stage liver disease with severe complications renders chronic liver disease a global health burden. Because of the lack of effective medication, transplantation remains the only and final curative option for end-stage liver disease. Since the demand for organ transplants by far exceeds the supply, other treatment options are urgently required to prevent progression and improve end-stage liver disease. Statins are primarily cholesterol-lowering drugs used for primary or secondary prevention of cardiovascular diseases. In addition to the primary effect, statins act beneficially through different pleiotropic mechanisms on inflammation, fibrosis, endothelial function, thrombosis, and coagulation to improve chronic liver diseases. However, concerns remain about the efficacy and safety of statin treatment because of their potential hepatotoxic risks, and as of now, these risks impede broader use of statins in the treatment of chronic liver diseases. The aim of this review is to comprehensively describe the mechanisms by which statins improve prospects for different chronic liver diseases with special focus on the pathophysiological rationale and the clinical experience of statin use in the treatment of liver diseases.

Chronic Kidney Disease

The definition and classification of chronic kidney disease (CKD) have evolved over time, but current international guidelines define this condition as decreased kidney function shown by glomerular filtration rate (GFR) of less than 60 mL/min per 1·73 m², or markers of kidney damage, or both, of at least 3 months duration, regardless of the underlying cause. Diabetes and hypertension are the main causes of CKD in all high-income and middle-income countries, and also in many low-income countries. Incidence, prevalence, and progression of CKD also vary within countries by ethnicity and social determinants of health, possibly through epigenetic influence. Many people are asymptomatic or have non-specific symptoms such as lethargy, itch, or loss of appetite. Diagnosis is commonly made after chance findings from screening tests (urinary dipstick or blood tests), or when symptoms become severe. The best available indicator of overall kidney function is GFR, which is measured either via exogenous markers (eg, DTPA, iohexol), or estimated using equations. Presence of proteinuria is associated with increased risk of progression of CKD and death. Kidney biopsy samples can show definitive evidence of CKD, through common changes such as glomerular sclerosis, tubular atrophy, and interstitial fibrosis. Complications include anaemia due to reduced production of erythropoietin by the kidney; reduced red blood cell survival and iron deficiency; and mineral bone disease caused by disturbed vitamin D, calcium, and phosphate metabolism. People with CKD are five to ten times more likely to die prematurely than they are to progress to end stage kidney disease. This increased risk of death rises exponentially as kidney function worsens and is largely attributable to death from cardiovascular disease, although cancer incidence and mortality are also increased. Health-related quality of life is substantially lower for people with CKD than for the general population, and falls as GFR declines. Interventions targeting specific symptoms, or aimed at supporting educational or lifestyle considerations, make a positive difference to people living with CKD. Inequity in access to services for this disease disproportionally affects disadvantaged populations, and health service provision to incentivise early intervention over provision of care only for advanced CKD is still evolving in many countries.

New therapeutic agents in diabetic nephropathy

Studies investigating diabetic nephropathy (DN) have mostly focused on interpreting the pathologic molecular mechanisms of DN, which may provide valuable tools for early diagnosis and prevention of disease onset and progression. Currently, there are few therapeutic drugs for DN, which mainly consist of antihypertensive and antiproteinuric measures that arise from strict renin-angiotensin-aldosterone system inactivation. However, these traditional therapies are suboptimal and there is a clear, unmet need for treatments that offer effective schemes beyond glucose control. The complexity and heterogeneity of the DN entity, along with ambiguous renal endpoints that may deter accurate appraisal of new drug potency, contribute to a worsening of the situation. To address these issues, current research into original therapies to treat DN is focusing on the intrinsic renal pathways that intervene with intracellular signaling of anti-inflammatory, antifibrotic, and metabolic pathways. Mounting evidence in support of the favorable metabolic effects of these novel agents with respect to the renal aspects of DN supports the likelihood of systemic beneficial effects as well. Thus, when translated into clinical use, these novel agents would also address the comorbid factors associated with diabetes, such as obesity and risk of cardiovascular disease. This review will provide a discussion of the promising and effective therapeutic agents for the management of DN.

A High Content Screening Assay to Identify Compounds with Anti-Epithelial-Mesenchymal Transition Effects from the Chinese Herbal Medicine Tong-Mai-Yang-Xin-Wan

Chronic kidney disease (CKD) is a worldwide health problem with growing prevalence in developing countries. Renal tubular epithelial-mesenchymal transition (EMT) is a critical step and key factor in the development of this condition. Renal tubulointerstitial fibrosis is a basic pathological change at the later stages of the disease. Therefore, blocking the development of EMT could be a critical factor in curing CKD. We have established a cell-based high-content screening (HCS) method to identify inhibitors of EMT in human proximal tubular epithelial (HK-2) cells by automatic acquisition and processing of dual-fluorescent labeled images. With the aid of chromatographic separation and mass spectrometry, we achieved the rapid and reliable screening of active compounds from the Chinese herbal medicine Tong-Mai-Yang-Xin-Wan (TMYX) for treating EMT. Five fractions were found to exert anti-EMT activity and were further identified by liquid chromatography coupled with tandem mass spectrometry. Glycyrrhizic acid, glyasperin A, and licorisoflavan A were found to inhibit EMT. The proposed approach was successfully applied to screen active compounds from TMYX on TGF-β1-stimulated HK-2 cells and may offer a new means for identifying lead compounds for treating EMT from registered Chinese herbal medicines.

Impact of renal function on the effects of LDL cholesterol lowering with statin-based regimens: a meta-analysis of individual participant data from 28 randomised trials

BACKGROUND

Statin therapy is effective for the prevention of coronary heart disease and stroke in patients with mild-to-moderate chronic kidney disease, but its effects in individuals with more advanced disease, particularly those undergoing dialysis, are uncertain.

METHODS

We did a meta-analysis of individual participant data from 28 trials (n=183 419), examining effects of statin-based therapy on major vascular events (major coronary event [non-fatal myocardial infarction or coronary death], stroke, or coronary revascularisation) and cause-specific mortality. Participants were subdivided into categories of estimated glomerular filtration rate (eGFR) at baseline. Treatment effects were estimated with rate ratio (RR) per mmol/L reduction in LDL cholesterol.

FINDINGS

Overall, statin-based therapy reduced the risk of a first major vascular event by 21% (RR 0·79, 95% CI 0·77-0·81; p<0·0001) per mmol/L reduction in LDL cholesterol. Smaller relative effects on major vascular events were observed as eGFR declined (p=0·008 for trend; RR 0·78, 99% CI 0·75-0·82 for eGFR ≥60 mL/min per 1·73 m(2); 0·76, 0·70-0·81 for eGFR 45 to <60 mL/min per 1·73 m(2); 0·85, 0·75-0·96 for eGFR 30 to <45 mL/min per 1·73 m(2); 0·85, 0·71-1·02 for eGFR <30 mL/min per 1·73 m(2) and not on dialysis; and 0·94, 0·79-1·11 for patients on dialysis). Analogous trends by baseline renal function were seen for major coronary events (p=0·01 for trend) and vascular mortality (p=0·03 for trend), but there was no significant trend for coronary revascularisation (p=0·90). Reducing LDL cholesterol with statin-based therapy had no effect on non-vascular mortality, irrespective of eGFR.

INTERPRETATION

Even after allowing for the smaller reductions in LDL cholesterol achieved by patients with more advanced chronic kidney disease, and for differences in outcome definitions between dialysis trials, the relative reductions in major vascular events observed with statin-based treatment became smaller as eGFR declined, with little evidence of benefit in patients on dialysis. In patients with chronic kidney disease, statin-based regimens should be chosen to maximise the absolute reduction in LDL cholesterol to achieve the largest treatment benefits.

FUNDING

UK Medical Research Council, British Heart Foundation, Cancer Research UK, European Community Biomed Programme, Australian National Health and Medical Research Council, Australian National Heart Foundation.

Influence of Late Vascular Inflammation on Long-Term Outcomes Among Patients Undergoing Implantation of Drug Eluting Stents: Role of C-Reactive Protein

Background

Elevation of C‐reactive protein (CRP) as a marker of vascular inflammation at a late phase of drug‐eluting stent (DES) implantation may predict subsequent major adverse cardiac events (MACE).

Methods and Results

In 1234 consecutive patients undergoing DES implantation, CRP was measured both before (baseline) and 8 to 12 months after (late phase) stenting, and the relationship between elevation of CRP (>2.0 mg/L) and subsequent MACE (all cause death, nonfatal myocardial infarction, target lesion revascularization, and other additional revascularization) was assessed. As results, CRP was elevated in 38.0% of patients at baseline and in 23.6% during late phase (P<0.0001), and hazard ratio (HR) for MACE was 1.52 (95% confidence interval [95% CI] 1.21–1.93, P=0.0004) at baseline versus 4.00 (95% CI 3.16–5.05, P<0.0001) in late phase. By multivariable analysis, late‐phase CRP elevation (HR 3.60, 95% CI: 2.78–4.68, P<0.0001), chronic kidney disease (CKD) (HR 1.41, 95% CI: 1.10–1.84, P=0.01), and number of diseased segments (HR 1.19, 95% CI: 1.08–1.30, P=0.0002) were positive predictors of MACE, whereas statin use (HR 0.66, 95% CI 0.50–0.87, P=0.003) was a negative predictor. Propensity score–matched analysis also confirmed the effect of late‐phase CRP on MACE (HR 3.39, 95% CI 2.52–4.56, P<0.0001). In prediction of the late‐phase CRP elevation, CKD (odds ratio [OR] 1.71, 95% CI 1.24–2.36, P=0.001) and baseline CRP elevation (OR 3.48, 95% CI 2.55–4.74, P<0.0001) were positive predictors, whereas newer generation DES (OR 0.59, 95% CI 0.41–0.84, P=0.003) and statin therapy (OR 0.68, 95% CI 0.47–0.97, P=0.03) were negative predictors.

Conclusions

Monitoring the late‐phase CRP may be helpful to identify a high‐risk subset for MACE among patients undergoing DES implantation.

Clinical action measures improve the reliability of feedback on quality of care in diabetes centres: a retrospective cohort study

Background

Assessment of quality of care using classical threshold measures (TM) is open to debate. Measures that take into account the clinician’s actions and the longitudinal nature of chronic care are more reliable, although their major limitation is that they require more sophisticated electronic health records. We created a clinical action measure (CAM) for the control of LDL and non-HDL cholesterol from low-complexity data, and investigated how quality of care in individual diabetes centres based on the CAM is related to that based on the classical TM.

Methods

Data was used from 3421 diabetes patients treated in 95 centres, collected in two consecutive retrospective data collections. Patients met the TM when their index value was below target. Patients met the CAM when their index value was below target or above target but for whom treatment initiation or intensification, or possible contraindication, was indicated.

Results

Based on the TM, 60–70 % of the patients received good care. This percentage increased significantly using the CAM (+5 %, p < 0.001). At the centre level, the CAM was associated with a higher median score, and a change in position among centres (‘poor’, ‘good’ or ‘excellent’ performer) for 5–10 % of the centres.

Conclusions

Judging quality of diabetes care of a centre based on a TM may be misleading. Low-complexity data available from a quality improvement initiative can be used to construct a more fair and feasible measure of quality of care.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-016-1670-5) contains supplementary material, which is available to authorized users.

Improvement in Renal Function and Reduction in Serum Uric Acid with Intensive Statin Therapy in Older Patients: A Post Hoc Analysis of the SAGE Trial

Background

Improvement in renal function and decreases in serum uric acid (SUA) have been reported following prolonged high-intensity statin (HMG-CoA reductase inhibitor) therapy. This post hoc analysis of the SAGE trial examined the effect of intensive versus less intensive statin therapy on renal function, safety, and laboratory parameters, including SUA, in elderly coronary artery disease (CAD) patients (65–85 years) with or without chronic kidney disease (CKD).

Methods

Patients were randomized to atorvastatin 80 mg/day or pravastatin 40 mg/day and treated for 12 months. Patients were stratified using Modification of Diet in Renal Disease (MDRD) estimated glomerular filtration rates (eGFRs) in CKD (eGFR <60 mL/min/1.73 m²) and non-CKD populations.

Results

Of the 893 patients randomized, 858 had complete renal data and 418 of 858 (49 %) had CKD (99 % Stage 3). Over 12 months, eGFR increased with atorvastatin and remained stable with pravastatin (+2.38 vs. +0.18 mL/min/1.73 m², respectively; p < 0.0001). MDRD eGFR improved significantly in both CKD treatment arms; however, the increased eGFR in patients without CKD was significantly greater with atorvastatin (+2.08 mL/min/1.73 m²) than with pravastatin (−1.04 mL/min/1.73 m²). Modest reductions in SUA were observed in both treatment arms, but a greater fall occurred with atorvastatin than with pravastatin (−0.52 vs. −0.09 mg/dL, p < 0.0001). Change in SUA correlated negatively with changes in eGFR and positively with changes in low-density lipoprotein cholesterol. Reports of myalgia were rare (3.6 % CKD; 5.7 % non-CKD), and there were no episodes of rhabdomyolysis. Elevated serum alanine and aspartate transaminase to >3 times the upper limit of normal occurred in 4.4 % of atorvastatin- and 0.2 % of pravastatin-treated patients.

Conclusion

Intensive management of dyslipidemia in older patients with stable coronary heart disease may have beneficial effects on renal function and SUA.

Association of statin use and the risk of end-stage renal disease: A nationwide Asian population-based case-control study

BACKGROUND

Although experimental models have shown that statins could alleviate glomerular damage and decrease urinary protein excretion, the renal effects of statins remain unclear. A case-control study was conducted using data from Taiwan's National Health Insurance system.

METHODS

An end-stage renal disease (ESRD) group comprising 11,486 patients was established. Each patient was frequency-matched by age, sex, and comorbidities with one person without ESRD from the general population. Logistic regression analysis was performed to estimate the influence of statin use on ESRD risk.

RESULTS

The overall adjusted odds ratios (ORs) of ESRD among patients who received statins was 1.59 (95% confidence interval=1.50-1.68). The raised ESRD risk of statin remained consolidated regardless of statin type (P<.001), except lovastatin. Further, while stratified by cumulative define daily dose, the risk of ESRD increased with accumulative dosage of statins (P for trend<.001).

CONCLUSION

This population-based case-control study showed that statin use might be associated with increased ESRD risks. Large-scale randomized clinical trial encompassing statins of different kinds and populations of different comorbidities would be helpful to clarify the potential ESRD risks of statin users.

Prescription Rates of Cardiovascular Medications in a Large UK Primary Care Chronic Kidney Disease Cohort

BACKGROUND AND AIMS

Chronic kidney disease (CKD) is associated with increased cardiovascular (CV) risk. Guidelines have suggested the universal use of statins in CKD but aspirin's role is less well defined. The aim of this study was to determine prescription rates for statins and aspirin in a UK-based CKD cohort and to establish factors that influenced prescription rates.

METHODS

We used data from a UK primary care CKD cohort to study rates of prescription of statins and aspirin. Simple rates were initially calculated. Binary logistic regression was utilized with either statin or aspirin prescription as the outcome variable and covariates including demographic details and comorbidities.

RESULTS

There were 31,056 individuals in the cohort with at least one estimated glomerular filtration rate (eGFR) of <60 ml/min/1.73 m2, and 65.1% individuals had 2 eGFR results <60 ml/min/1.73 m2 more than 3 months apart. Mean eGFR at baseline was 51.1 ml/min/1.73 m2 (SD 9.1), and 64.9% had a diagnosis of hypertension (HTN), 18.8% had diabetes mellitus (DM) and 29.8% a history of CV disease. Statins were prescribed to 14,972 (48.2%) and aspirin to 11,023 (35.5%). The regression model suggested that CV disease, HTN and DM influenced the prescriptions of statins and aspirin but overall CKD stage, calculated by either eGFR or proteinuria, did not.

CONCLUSIONS

Prescriptions of statins and aspirin in CKD is based more on the presence of comorbidities than the CKD severity. Further physician and patient education of the increased CV risk associated with CKD and its suitability for CV medication intervention is required.

Effects of Atorvastatin Dose and Concomitant Use of Angiotensin-Converting Enzyme Inhibitors on Renal Function Changes over Time in Patients with Stable Coronary Artery Disease: A Prospective Observational Study

Angiotensin-converting enzyme inhibitors (ACEI) and statins are widely used in patients with coronary artery disease (CAD). Our aim was to compare changes in glomerular filtration rate (GFR) over time in subjects with stable CAD according to atorvastatin dose and concomitant use of ACEI. We studied 78 men with stable CAD referred for an elective coronary angiography who attained the then-current guideline-recommended target level of low-density lipoproteins (LDL) cholesterol below 2.5 mmol/L in a routine fasting lipid panel on admission and were receiving atorvastatin at a daily dose of 10-40 mg for ≥3 months preceding the index hospitalization. Due to an observational study design, atorvastatin dosage was not intentionally modified for other reasons. GFR was estimated during index hospitalization and at about one year after discharge from our center. Irrespective of ACEI use, a prevention of kidney function loss was observed only in those treated with the highest atorvastatin dose. In 38 subjects on ACEI, both of the higher atorvastatin doses were associated with increasing beneficial effects on GFR changes (mean ± SEM: -4.2 ± 2.4, 1.1 ± 1.6, 5.2 ± 2.4 mL/min per 1.73 m² for the 10-mg, 20-mg and 40-mg atorvastatin group, respectively, p = 0.02 by ANOVA; Spearman's rho = 0.50, p = 0.001 for trend). In sharp contrast, in 40 patients without ACEI, no significant trend effect was observed across increasing atorvastatin dosage (respective GFR changes: -1.3 ± 1.0, -4.7 ± 2.1, 4.8 ± 3.6 mL/min per 1.73 m², p = 0.02 by ANOVA; rho = 0.08, p = 0.6 for trend). The results were substantially unchanged after adjustment for baseline GFR or time-dependent variations of LDL cholesterol. Thus, concomitant ACEI use appears to facilitate the ability of increasing atorvastatin doses to beneficially modulate time-dependent changes in GFR in men with stable CAD.

[An updated overview of the high intensity lipid lowering therapy in high cardiovascular risk patients]

Statins are highly effective drugs to decrease the plasma concentrations of atherogenic lipoproteins and prevent cardiovascular disease. The clinical practice guidelines recommend the use of high-intensity statins to lower LDL-cholesterol by at least 50% in patients with CVD and those at high cardiovascular risk. The recommendations for the treatment of hypercholesterolaemia by the ACC/AHA have led to a paradigm shift in cardiovascular prevention. These recommendations have abandoned the therapeutic goals of LDL-cholesterol, and recommend the treatment with statins of high or moderate intensity in four high cardiovascular risk groups. These recommendations are different from the European guidelines on cardiovascular disease prevention, in which their objectives are still towards LDL-cholesterol. This paper reviews this controversy from different angles and from the perspective of the Spanish Interdisciplinary Committee for Cardiovascular Disease Prevention. Intervention studies with high intensity statins in primary prevention, in patients with acute coronary syndrome, and with stable ischaemic heart disease are also described. Likewise, treatment with statins of high intensity is addressed in terms of their effectiveness in cardiovascular prevention and in terms of their safety, with particular attention to muscle effects, as well as taking into account the pharmacological characteristics of the different statins and the increased safety of those with less potential for interactions. Finally, new agents are described for the treatment of hypercholesterolaemia, with special emphasis on anti-PCSK9 monoclonal antibodies, a new therapeutic group for the treatment of hypercholesterolaemia that will offer a huge progress in the prevention of cardiovascular diseases.

Statin Adverse Events in Primary Prevention: Between Randomized Trials and Observational Studies

Considerable debate exists regarding who might benefit from statins for primary prevention. Statins have wide pleotropic effects, which contribute to their efficacy in lowering cardiovascular disease but may also result in adverse events (AEs). Caveats in identifying AEs in randomized controlled trials (RCTs) include the lack of a standardized definition of statin-associated AEs, the differences in properties of different statins, the selectivity of RCTs in choosing their participants, the presence of high rate of nonadherence/withdrawal from trials and other concerns related to study design and conflict of interest. Caveats in identifying or overestimating AEs in observational studies include failure to identify baseline confounders, ascertainment bias, confounding by indication and healthy user bias. Statin use in observational studies may be a surrogate marker for higher socioeconomic standards, access to health care or use of other preventive services. Integrating evidence from both RCTs and observational studies is of paramount importance for appropriate patient-centered decision.

Vascular calcification, bone and mineral metabolism after kidney transplantation

The development of end stage renal failure can be seen as a catastrophic health event and patients with this condition are considered at the highest risk of cardiovascular disease among any other patient groups and risk categories. Although kidney transplantation was hailed as an optimal solution to such devastating disease, many issues related to immune-suppressive drugs soon emerged and it became evident that cardiovascular disease would remain a vexing problem. Progression of chronic kidney disease is accompanied by profound alterations of mineral and bone metabolism that are believed to have an impact on the cardiovascular health of patients with advanced degrees of renal failure. Cardiovascular risk factors remain highly prevalent after kidney transplantation, some immune-suppression drugs worsen the risk profile of graft recipients and the alterations of mineral and bone metabolism seen in end stage renal failure are not completely resolved. Whether this complex situation promotes progression of vascular calcification, a hall-mark of advanced chronic kidney disease, and whether vascular calcifications contribute to the poor cardiovascular outcome of post-transplant patients is reviewed in this article.

Modulation of stroke risk in chronic kidney disease

Stroke is the second most common cause of death and the leading cause of neurological disability worldwide, with huge economic costs and tragic human consequences. Both chronic kidney disease (CKD) and end-stage kidney disease are associated with a significantly increased risk of stroke. However, to date this has generated far less interest compared with the better-recognized links between cardiac and renal disease. Common risk factors for stroke, such as hypertension, hypercholesterolaemia, smoking and atrial fibrillation, are shared with the general population but are more prevalent in renal patients. In addition, factors unique to these patients, such as disorders of mineral and bone metabolism, anaemia and its treatments as well as the process of dialysis itself, are all also postulated to further increase the risk of stroke. In the general population, advances in medical therapies mean that effective primary and secondary prevention therapies are available for many patients. The development of specialist stroke clinics and acute stroke units has also improved outcomes after a stroke. Emerging therapies such as thrombolysis and thrombectomy are showing increasingly beneficial results. However, patients with CKD and on dialysis have different risk profiles that must be taken into account when considering the potential benefits and risks of these treatments. Unfortunately, these patients are either not recruited or formally excluded from major clinical trials. There is still much work to be done to harness effective stroke treatments with an acceptable safety profile for patients with CKD and those on dialysis.

Characterisation of cardiomyopathy by cardiac and aortic magnetic resonance in patients new to hemodialysis

Objectives

Cardiomyopathy is a key factor in accelerated cardiovascular mortality in haemodialysis (HD) patients. We aimed to phenotype cardiac and vascular dysfunction by tagged cardiovascular magnetic resonance (CMR) imaging in patients recently commencing HD.

Methods

Fifty-four HD patients and 29 age and sex-matched controls without kidney disease were studied. Left ventricular (LV) mass, volumes, ejection fraction (EF), concentric remodelling, peak-systolic circumferential strain (PSS), peak diastolic strain rate (PDSR), LV dyssynchrony, aortic distensibility and aortic pulse wave velocity were determined.

Results

Global systolic function was reduced (EF 51 ± 10%, HD versus 59 ± 5%, controls, p < 0.001; PSS 15.9 ± 3.7% versus 19.5 ± 3.3%, p < 0.001). Diastolic function was decreased (PDSR 1.07 ± 0.33s^-1 versus 1.31 ± 0.38s^-1, p = 0.003). LV mass index was increased (63[54,79]g/m² versus 46[42,53]g/m², p < 0.001). Anteroseptal reductions in PSS were apparent. These abnormalities remained prevalent in the subset of HD patients with preserved EF >50% (n = 35) and the subset of HD patients without diabetes (n = 40). LV dyssynchrony was inversely correlated to diastolic function, EF and aortic distensibility. Diastolic function was inversely correlated to LV dyssynchrony, concentric remodelling, age and aortic pulse wave velocity.

Conclusion

Patients new to HD have multiple cardiac and aortic abnormalities as characterised by tagged CMR. Cardio-protective interventions are required from initiation of therapy.

Key Points

• First characterisation of cardiomyopathy by tagged CMR in haemodialysis patients.

• Diastolic function was correlated to LV dyssynchrony, concentric remodelling and aortic PWV.

• Reductions in strain localised to the septal and anterior wall.

• Bioimpedance measures were unrelated to LV strain, suggesting volume-independent pathogenetic mechanisms.

• Multiple abnormalities persisted in the HD patient subset with preserved EF or without diabetes.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-015-4096-2) contains supplementary material, which is available to authorized users.

Cost-effectiveness of Simvastatin plus Ezetimibe for Cardiovascular Prevention in CKD: Results of the Study of Heart and Renal Protection (SHARP)

Background

Simvastatin, 20 mg, plus ezetimibe, 10 mg, daily (simvastatin plus ezetimibe) reduced major atherosclerotic events in patients with moderate to severe chronic kidney disease (CKD) in the Study of Heart and Renal Protection (SHARP), but its cost-effectiveness is unknown.

Study Design

Cost-effectiveness of simvastatin plus ezetimibe in SHARP, a randomized controlled trial.

Setting & Population

9,270 patients with CKD randomly assigned to simvastatin plus ezetimibe versus placebo; participants in categories by 5-year cardiovascular risk (low, <10%; medium, 10%-<20%; or high, ≥20%) and CKD stage (3, 4, 5 not on dialysis, or on dialysis therapy).

Model, Perspective, & Timeline

Assessment during SHARP follow-up from the UK perspective; long-term projections.

Intervention

Simvastatin plus ezetimibe (2015 UK £1.19 per day) during 4.9 years’ median follow-up in SHARP; scenario analyses with high-intensity statin regimens (2015 UK £0.05-£1.06 per day).

Outcomes

Additional health care costs per major atherosclerotic event avoided and per quality-adjusted life-year (QALY) gained.

Results

In SHARP, the proportional reductions per 1 mmol/L of low-density lipoprotein (LDL) cholesterol reduction with simvastatin plus ezetimibe in all major atherosclerotic events of 20% (95% CI, 6%-32%) and in the costs of vascular hospital episodes of 17% (95% CI, 4%-28%) were similar across participant categories by cardiovascular risk and CKD stage. The 5-year reduction in major atherosclerotic events per 1,000 participants ranged from 10 in low-risk to 58 in high-risk patients and from 28 in CKD stage 3 to 36 in patients on dialysis therapy. The net cost per major atherosclerotic event avoided with simvastatin plus ezetimibe compared to no LDL-lowering regimen ranged from £157,060 in patients at low risk to £15,230 in those at high risk (£30,500-£39,600 per QALY); and from £47,280 in CKD stage 3 to £28,180 in patients on dialysis therapy (£13,000-£43,300 per QALY). In scenario analyses, generic high-intensity statin regimens were estimated to yield similar benefits at substantially lower cost.

Limitations

High-intensity statin-alone regimens were not studied in SHARP.

Conclusions

Simvastatin plus ezetimibe prevented atherosclerotic events in SHARP, but other less costly statin regimens are likely to be more cost-effective for reducing cardiovascular risk in CKD.

Plasma Nitration of High-Density and Low-Density Lipoproteins in Chronic Kidney Disease Patients Receiving Kidney Transplants

BACKGROUND

Functional abnormalities of high-density lipoprotein (HDL) could contribute to cardiovascular disease in chronic kidney disease patients. We measured a validated marker of HDL dysfunction, nitrated apolipoprotein A-I, in kidney transplant recipients to test the hypothesis that a functioning kidney transplant reduces serum nitrated apoA-I concentrations.

METHODS

Concentrations of nitrated apoA-I and apoB were measured using indirect sandwich ELISA assays on sera collected from each transplant subject before transplantation and at 1, 3, and 12 months after transplantation. Patients were excluded if they have history of diabetes, treatment with lipid-lowering medications or HIV protease inhibitors, prednisone dose > 15 mg/day, nephrotic range proteinuria, serum creatinine > 1.5 mg/dL, or active inflammatory disease. Sera from 18 transplanted patients were analyzed. Four subjects were excluded due to insufficient data. Twelve and eight patients had creatinine < 1.5 mg/dL at 3 and 12 months after transplantation, respectively. RESULTS. Nitrated apoA-I was significantly reduced at 12 months after transplantation (p = 0.039). The decrease in apoA-I nitration was associated with significant reduction in myeloperoxidase (MPO) activity (p = 0.047). In contrast to apoA-I, nitrated apoB was not affected after kidney transplantation.

CONCLUSIONS

Patients with well-functioning grafts had significant reduction in nitrated apoA-I 12 months after kidney transplantation. Further studies are needed in a large cohort to determine if nitrated apoA-I can be used as a valuable marker for cardiovascular risk stratification in chronic kidney disease.

Comparative Effectiveness of Statin Therapy in Chronic Kidney Disease and Acute Myocardial Infarction: A Retrospective Cohort Study

BACKGROUND

Whether there is a kidney function threshold to statin effectiveness in patients with acute myocardial infarction is poorly understood. Our study sought to help fill this gap in clinical knowledge.

METHODS

We undertook a new-user cohort study of the effectiveness of statin therapy by level of estimated glomerular filtration rate (eGFR) in adults who were hospitalized for myocardial infarction between 2000 and 2008. Data came from the Cardiovascular Research Network. The primary clinical outcomes were 1-year all-cause mortality and cardiovascular hospitalizations, with adverse outcomes of myopathy and development of diabetes mellitus. We calculated incidence rates, the number needed to treat, and used Cox proportional hazards regression with propensity score matching and adjustment to control for confounding, with testing for variation of effect by level of kidney function.

RESULTS

Compared with statin non-initiators (n = 5583), statin initiators (n = 5597) had a lower propensity score-adjusted risk for death (hazard ratio 0.79; 95% confidence interval [CI], 0.71-0.88) and cardiovascular hospitalizations (hazard ratio 0.90; 95% CI, 0.82-1.00). We found little evidence of variation in effect by level of eGFR (P = .86 for death; P = .77 for cardiovascular hospitalization). Adverse outcomes were similar for statin initiators and statin non-initiators. The number needed to treat to prevent 1 additional death over 1 year of follow-up ranged from 15 (95% CI, 11-28) for eGFR <30 mL/min/1.73 m(2) requiring statin treatment over 2 years to prevent 1 additional death, to 67 (95% CI, 49-118) for patients with eGFR >90 mL/min/1.73 m(2).

CONCLUSIONS

Our findings suggest that there is potential for important public health gains by increasing the routine use of statin therapy for patients with lower levels of kidney function.

Association between higher rates of cardioprotective drug use and survival in patients on dialysis

BACKGROUND

While cardiovascular (CV) disease is a leading cause of morbidity and mortality in patients on chronic dialysis, utilization rates of cardioprotective drugs for dialysis patients remain low. This study sought to determine whether higher rates of cardioprotective drug use among dialysis patients might increase survival.

METHODS

A retrospective cohort of incident dialysis patients (n = 50,468) with dual eligibility for U.S. Medicare and Medicaid was constructed using USRDS data linked with billing claims. Medication exposures included angiotensin converting enzyme inhibitors/angiotensin receptor blockers (ACEIs/ARBs), β-blockers, calcium channel blockers (CCBs), and HMG-CoA reductase inhibitors (statins) prescribed within 90 days of dialysis initiation. The outcomes were one- and two-year survival and CV event-free survival. Variation in treatment rates based on local area practice styles were used as instruments in instrumental variable (IV) estimation, yielding average treatment effect estimates for patients whose treatment choices were affected by local area practice styles.

RESULTS

Patients aged 65 years and older comprised 47.4% of the sample, while 59.5% were female and 35.0% were white. The utilization rate was 40.7% for ACEIs/ARBs, 43.0% for β-blockers, 50.7% for CCBs and 26.4% for statins. The local area practice style instruments were highly significantly related to cardioprotective drug use in dialysis patients (Chow-F values > 10). IV estimates showed only that higher rates of β-blockers increased one-year survival (β = 0.161, P-value = 0.020) and CV event-free survival (β = 0.189, P-value = 0.033), but that higher rates of CCBs decreased two-year CV event-free survival (β = -0.520, P-value = 0.009).

CONCLUSIONS

This study suggests that higher utilization rates of β-blockers might yield higher survival rates for dialysis patients. However, higher rates of the other drugs studied had no correlations with survival, and higher CCB rates might actually reduce CV-event free survival. Since the benefits of cardioprotective drugs may vary across dialysis patients, the study findings should be interpreted only with respect to changes of utilization rates around the rates observed in this study.

Cardiovascular secondary prevention in high-risk patients: a randomized controlled trial sub-study

Background

Enhanced cardiovascular secondary preventive follow-up is needed to improve adherence to recommended low-density lipoprotein cholesterol (LDL-C) and blood pressure (BP) levels. Patients with diabetes mellitus (DM) or chronic kidney disease (CKD) have a high risk of recurrent events. Secondary prevention is therefore essential in these patients.

Methods

Patients with acute coronary syndrome, stroke, or transient ischemic attack were randomized to nurse-based telephone follow-up (intervention) or usual care (control). LDL-C and BP were measured at 1 month (baseline) and 12 months post-discharge. Intervention patients with above-target values at baseline received medication titration to achieve treatment goals. Values measured for control patients were given to the patient’s general practitioner for assessment.

Results

The final analyses included 225 intervention and 215 control patients with DM or CKD. Among patients with above-target baseline values, the following 12-month values were recorded for intervention and control patients, respectively: LDL-C, 2.2 versus 3.0 mmol/L (p < 0.001); and median systolic BP (SBP), 140 versus 145 mmHg (p = 0.26). Among patients with above-target values at baseline, 52.3 % of intervention patients reached target LDL-C values at 12 months versus 21.3 % of control patients (absolute difference of 30.9 %, 95 % CI 16.1 to 43.8 %), and there was a non-significant trend of more intervention patients reaching target SBP (49.4 % versus 36.8 %; absolute difference of 12.6 %, 95 % CI −1.7 to 26.2 %).

Conclusions

Cardiovascular secondary prevention with nurse-based telephone follow-up was more effective than usual care in improving LDL-C levels 12 months after discharge for patients with DM or CKD.

Trial registration

ISRCTN registry; ISRCTN96595458 (date of registration 10 July 2011) and ISRCTN23868518 (date of registration 13 May 2012).

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-015-0115-0) contains supplementary material, which is available to authorized users.

Effects of Long-Term Statin Therapy in Coronary Artery Disease Patients with or without Chronic Kidney Disease

INTRODUCTION

The effect of long-term statin therapy is essential for secondary prevention of adverse clinical outcomes of coronary artery disease (CAD) patients. No study has compared the effects of long-term statin treatment in CAD patients with or without chronic kidney disease (CKD) and CKD only patients.

METHODS

We compared the effects of long-term statin therapy (average follow-up time 5.79 years) in terms of major adverse cardiovascular events (MACE), all-cause death, and cardiac death among 570 CAD patients with or without CKD and 147 CKD only patients.

RESULTS

The all-cause death and cardiac death of the patients with CAD and CKD (24.4% and 20.4%) doubled those of CAD only patients (10.7% and 9.1%) (P < 0.001). Long-term statin therapy dramatically reduced the rates of both MACE and all-cause death/cardiac death (by 20.5% and 28.6%/27.7%, resp.) in CAD and CKD patients. CKD only patients had no significant adverse clinical outcomes and were not responsive to long-term statin therapy.

CONCLUSION

Chinese CAD patients with CKD had dramatically high rates of adverse clinical outcomes; for them, long-term statin therapies were exceptionally effective in improving morbidity and mortality. CKD patients who had no cardiovascular disease initially can prognose good clinical outcomes and do not require statin treatment.

Effects of lipid-lowering treatment on circulating microparticles in patients with diabetes mellitus and chronic kidney disease

BACKGROUND

Elevated levels of circulating microparticles (MPs) may contribute to the high cardiovascular risk in diabetes mellitus (DM) and chronic kidney disease (CKD). Therefore, we investigated the effects of lipid-lowering treatment (LLT) with simvastatin alone (S) or with ezetimibe (S+E) on MPs in DM patients with or without CKD.

METHODS

After a placebo run-in period, 18 DM patients with an estimated glomerular filtration rate (eGFR) of 15-59 mL/min (CKD stages 3-4) (DM-CKD) and 21 DM patients with eGFR >75 mL/min (DM-only) were treated with S and S+E in a randomized, double-blind, crossover study. MPs from platelets, monocytes and endothelial cells (PMPs, MMPs and EMPs), and their expression of phosphatidylserine (PS), P-selectin, CD40 ligand (CD40L) and tissue factor (TF) were measured by flow cytometry.

RESULTS

At baseline, all types of MPs, except TF-positive MMPs, were elevated in DM-CKD compared with DM-only patients. All MPs, regardless of origin and phenotype, were inversely correlated with eGFR. S reduced the expression of P-selectin, TF and CD40L on PMPs and of TF on MMPs in both patient groups. S+E had no further effect. S also reduced total PS-positive procoagulant MPs, PMPs and MMPs in DM-CKD but not in DM-only patients.

CONCLUSIONS

DM patients with CKD stages 3-4 had elevated PMPs, EMPs and MMPs compared with DM patients with normal GFR. Simvastatin reduced procoagulant MPs, MMPs and PMPs in DM-CKD patients, suggesting a beneficial reduction of hypercoagulability in this high-risk patient group. Differences between DM-CKD and DM-only patients were counteracted by LLT.

Phosphate Binders and Clinical Outcomes in Patients with Stage 5D Chronic Kidney Disease

Knowledge informing the prescription and the choice of phosphate binders in end stage kidney disease (ESKD) patients has a weak evidentiary base. To date, no placebo-controlled trial based on meaningful clinical endpoints (death, cardiovascular events, bone fractures) has been performed to test the efficacy of these drugs. By the same token, we still lack solid proof that noncalcium binders afford better clinical outcomes as compared with calcium-based binders. Without proper trials, clinical decisions about the treatment of hyperphosphatemia rest on experience and contingent clinical judgment. The use of huge doses of calcium-based binders typically prescribed in the nineties now appears unwarranted. The relationship between phosphate and the risk of death is U shaped and moderate hyperphosphatemia carries just a mild-to-moderate risk excess and may not be seen as a compelling indication for the prescription of phosphate binders. Placebo-controlled randomized clinical trials assessing whether non-calcium and calcium-based binders reduce the risk of death and cardiovascular disease events in ESKD patients remain a public health priority.

Comprehensive Care for People With Diabetic Kidney Disease

IN BRIEF Diabetic kidney disease carries a heavy burden, both economically and in terms of quality of life, largely because of its very high risk for vascular disease. Coordinated, multidisciplinary care with attention to appropriate, timely screening and preventive management is crucial to reducing the morbidity and mortality of this devastating disease.

The Envy of Scholars: Applying the Lessons of the Framingham Heart Study to the Prevention of Chronic Kidney Disease

During the past 50 years, a dramatic reduction in the mortality rate associated with cardiovascular disease has occurred in the US and other countries. Statistical modeling has revealed that approximately half of this reduction is the result of risk factor mitigation. The successful identification of such risk factors was pioneered and has continued with the Framingham Heart Study, which began in 1949 as a project of the US National Heart Institute (now part of the National Heart, Lung, and Blood Institute). Decreases in total cholesterol, blood pressure, smoking, and physical inactivity account for 24%, 20%, 12%, and 5% reductions in the mortality rate, respectively. Nephrology was designated as a recognized medical professional specialty a few years later. Hemodialysis was first performed in 1943. The US Medicare End-Stage Renal Disease (ESRD) Program was established in 1972. The number of patients in the program increased from 5,000 in the first year to more than 500,000 in recent years. Only recently have efforts for risk factor identification, early diagnosis, and prevention of chronic kidney disease (CKD) been undertaken. By applying the approach of the Framingham Heart Study to address CKD risk factors, we hope to mirror the success of cardiology; we aim to prevent progression to ESRD and to avoid the cardiovascular complications associated with CKD. In this paper, we present conceptual examples of risk factor modification for CKD, in the setting of this historical framework.

Diabetic kidney disease

The kidney is arguably the most important target of microvascular damage in diabetes. A substantial proportion of individuals with diabetes will develop kidney disease owing to their disease and/or other co-morbidity, including hypertension and ageing-related nephron loss. The presence and severity of chronic kidney disease (CKD) identify individuals who are at increased risk of adverse health outcomes and premature mortality. Consequently, preventing and managing CKD in patients with diabetes is now a key aim of their overall management. Intensive management of patients with diabetes includes controlling blood glucose levels and blood pressure as well as blockade of the renin-angiotensin-aldosterone system; these approaches will reduce the incidence of diabetic kidney disease and slow its progression. Indeed, the major decline in the incidence of diabetic kidney disease (DKD) over the past 30 years and improved patient prognosis are largely attributable to improved diabetes care. However, there remains an unmet need for innovative treatment strategies to prevent, arrest, treat and reverse DKD. In this Primer, we summarize what is now known about the molecular pathogenesis of CKD in patients with diabetes and the key pathways and targets implicated in its progression. In addition, we discuss the current evidence for the prevention and management of DKD as well as the many controversies. Finally, we explore the opportunities to develop new interventions through urgently needed investment in dedicated and focused research. For an illustrated summary of this Primer, visit: http://go.nature.com/NKHDzg.

Glomerular filtration rate decline as a surrogate end point in kidney disease progression trials

Chronic kidney disease (CKD) is strongly associated with increased risks of progression to end-stage kidney disease (ESKD) and mortality. Clinical trials evaluating CKD progression commonly use a composite end point of death, ESKD or serum creatinine doubling. However, due to low event rates, such trials require large sample sizes and long-term follow-up for adequate statistical power. As a result, very few interventions targeting CKD progression have been tested in randomized controlled trials. To overcome this problem, the National Kidney Foundation and Food and Drug Administration conducted a series of analyses to determine whether an end point of 30 or 40% decline in estimated glomerular filtration rate (eGFR) over 2-3 years can substitute for serum creatinine doubling in the composite end point. These analyses demonstrated that these alternate kidney end points were significantly associated with subsequent risks of ESKD and death. However, the association between, and consistency of treatment effects on eGFR decline and clinical end points were influenced by baseline eGFR, follow-up duration and acute hemodynamic effects. The investigators concluded that a 40% eGFR decline is broadly acceptable as a kidney end point across a wide baseline eGFR range and that a 30% eGFR decline may be acceptable in some situations. Although these alternate kidney end points could potentially allow investigators to conduct shorter duration clinical trials with smaller sample sizes thereby generating evidence to guide clinical decision-making in a timely manner, it is uncertain whether these end points will improve trial efficiency and feasibility. This review critically appraises the evidence, strengths and limitations pertaining to eGFR end points.

Participation in a Structured Weight Loss Program and All-Cause Mortality and Cardiovascular Morbidity in Obese Patients With Chronic Kidney Disease

OBJECTIVE

To determine if participation in a weight loss program impacted upon a composite end point of all-cause mortality and cardiovascular morbidity in obese patients with chronic kidney disease (CKD).

DESIGN

Retrospective cohort study.

SUBJECTS

All patients with a body mass index (BMI) >30 kg/m(2) or >28 kg/m(2) with at least 1 comorbidity (hypertension, diabetes, or dyslipidemia) referred to an established weight management program (WMP) from 2005 to 2009 at a metropolitan tertiary teaching hospital were eligible for inclusion in the study cohort.

INTERVENTION

Twelve-month structured weight loss program.

MAIN OUTCOME MEASURES

Combined outcome of all-cause mortality, myocardial infarction, stroke, and hospitalization for congestive heart failure; kidney transplantation waitlisting.

RESULTS

A total of 169 obese patients with CKD commenced the WMP and 169 did not-becoming the observational control group (CON). There were no significant differences between groups for age, BMI, sex, ethnicity, smoking, hypertension, or kidney function at baseline, although CON included more patients with diabetes than WMP (49% vs. 38%, P = .03). Kaplan-Meier survival analysis with log-rank test differed between groups for the combined outcome (P = .03). Cox regression analysis with adjustment for age, sex, ethnicity, hypertension, diabetes, kidney function, baseline BMI, and smoking status, indicated that patients in WMP had a significantly longer event-free period for the combined outcome, than those in CON (adjusted hazard ratio 0.53; 95% confidence interval [CI] 0.29-0.97; P = .04). Participation in the WMP did not increase the likelihood of kidney transplantation waitlisting (odds ratio [OR] 1.06; 95% CI 0.39-2.87; P = .9). Lower baseline BMI and greater weight loss over 12 months were the only factors related to kidney transplantation waitlisting (adjusted R(2) = 0.426).

CONCLUSIONS

Participation in a structured weight loss program may be associated with improved outcomes in obese patients with CKD.

Inactive Matrix Gla-Protein Is Associated With Arterial Stiffness in an Adult Population-Based Study

Increased pulse wave velocity (PWV) is a marker of aortic stiffness and an independent predictor of mortality. Matrix Gla-protein (MGP) is a vascular calcification inhibitor that needs vitamin K to be activated. Inactive MGP, known as desphospho-uncarboxylated MGP (dp-ucMGP), can be measured in plasma and has been associated with various cardiovascular markers, cardiovascular outcomes, and mortality. In this study, we hypothesized that high levels of dp-ucMGP are associated with increased PWV. We recruited participants via a multicenter family-based cross-sectional study in Switzerland. Dp-ucMGP was quantified in plasma by sandwich ELISA. Aortic PWV was determined by applanation tonometry using carotid and femoral pulse waveforms. Multiple regression analysis was performed to estimate associations between PWV and dp-ucMGP adjusting for age, renal function, and other cardiovascular risk factors. We included 1001 participants in our analyses (475 men and 526 women). Mean values were 7.87±2.10 m/s for PWV and 0.43±0.20 nmol/L for dp-ucMGP. PWV was positively associated with dp-ucMGP both before and after adjustment for sex, age, body mass index, height, systolic and diastolic blood pressure (BP), heart rate, renal function, low- and high-density lipoprotein, glucose, smoking status, diabetes mellitus, BP and cholesterol lowering drugs, and history of cardiovascular disease (P≤0.01). In conclusion, high levels of dp-ucMGP are independently and positively associated with arterial stiffness after adjustment for common cardiovascular risk factors, renal function, and age. Experimental studies are needed to determine whether vitamin K supplementation slows arterial stiffening by increasing MGP carboxylation.

Defining, Treating, and Understanding Chronic Kidney Disease--A Complex Disorder

Chronic kidney disease (CKD) is prevalent in more than 20 million people in the United States. The majority of care provided to patients with this disease comes from primary care physicians, although it is often poorly understood. After an extensive literature review, it is clear that it can be difficult to classify and there are many barriers to care. Risk factors for both incident CKD and disease progression include hypertension, poor glycemic control, sociodemographic factors, acute kidney injury, metabolic acidosis, and possibly hyperuricemia and dietary factors. Treatment of patients with CKD should focus on mitigating risk factors, as well as common comorbidities such as cardiovascular disease, anemia, and bone mineral disease. Novel therapies such as pirfenidone, pentoxifylline, and endothelin-1 antagonists are being investigated with promising results.

A nephrology guide to reading and using systematic reviews of observational studies

Systematic reviews are an ideal way of summarizing evidence from primary studies. While systematic reviews of randomized trials are broadly used to summarize benefits and harms of interventions, systematic reviews of observational studies are useful to summarize data on prevalence of risk factors in a population, distribution of outcomes or associations of different risk factors with outcomes. Also, systematic reviews can be useful to clarify potential reasons for conflicting data found in primary studies and explore sources of heterogeneity (variation in primary study data) to better understand epidemiological data and generate hypotheses for candidate interventions to improve outcomes. Summarizing data from observational studies in systematic reviews is a powerful tool to distil existing prognostic evidence in specific settings and inform patients and healthcare providers. In this article, we describe how to critically appraise the methods, interpret the results and apply the findings of a systematic review of observational (prognostic) studies.

Survival Benefit of Statins in Hemodialysis Patients Awaiting Renal Transplantation

End-stage renal disease (ESRD) patients have extraordinarily high cardiovascular risk and mortality, yet the benefit of statins in this population remains unclear based on the randomized trials. We investigated the prognostic value of statins in a large, pure cohort of prospectively recruited patients with ESRD awaiting renal transplantation, and being followed up in a dedicated cardiac clinic. We prospectively collected demographic, clinical, laboratory, and pharmacological data on 423 consecutive ESRD patients on hemodialysis awaiting renal transplantation. Survival analysis was performed as a function of statin therapy. The baseline characteristics were as follows: age 57 ± 11 years, males 64%, diabetes mellitus in 68%, known coronary artery disease in 30%, left ventricular (LV) ejection fraction 61 ± 11%. Over a mean follow-up of 2 years, there were 43 deaths. Adjusted for age, gender, hypertension, body mass index, diabetes mellitus, coronary artery disease, smoking, and treatment with angiotensin converting enzyme inhibitor, β blocker, and antiplatelet medications, statin use was a predictor of lower mortality (hazard ratio 0.30, 95% confidence interval 0.11-0.79, p = 0.01). This beneficial effect of statin was supported by propensity score analysis (p = 0.02) and was consistent across all clinical subgroups. The benefit of statins seemed to be greater in those with LV hypertrophy and smoking. Statin therapy in hemodialysis patients awaiting renal transplant is independently associated with better survival supporting its use in this high-risk population.

Runx2 Expression in Smooth Muscle Cells Is Required for Arterial Medial Calcification in Mice

Arterial medial calcification (AMC) is a hallmark of aging, diabetes, and chronic kidney disease. Smooth muscle cell (SMC) transition to an osteogenic phenotype is a common feature of AMC, and is preceded by expression of runt-related transcription factor 2 (Runx2), a master regulator of bone development. Whether SMC-specific Runx2 expression is required for osteogenic phenotype change and AMC remains unknown. We therefore created an improved targeting construct to generate mice with floxed Runx2 alleles (Runx2(f/f)) that do not produce truncated Runx2 proteins after Cre recombination, thereby preventing potential off-target effects. SMC-specific deletion using SM22-recombinase transgenic allele mice (Runx2(ΔSM)) led to viable mice with normal bone and arterial morphology. After vitamin D overload, arterial SMCs in Runx2(f/f) mice expressed Runx2, underwent osteogenic phenotype change, and developed severe AMC. In contrast, vitamin D-treated Runx2(ΔSM) mice had no Runx2 in blood vessels, maintained SMC phenotype, and did not develop AMC. Runx2 deletion did not affect serum calcium, phosphate, fibroblast growth factor-23, or alkaline phosphatase levels. In vitro, Runx2(f/f) SMCs calcified to a much greater extent than those derived from Runx2(ΔSM) mice. These data indicate a critical role of Runx2 in SMC osteogenic phenotype change and mineral deposition in a mouse model of AMC, suggesting that Runx2 and downstream osteogenic pathways in SMCs may be useful therapeutic targets for treating or preventing AMC in high-risk patients.

High-intensity statin therapy in patients with chronic kidney disease: a systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy and safety of high-intensity statin therapy in patients with chronic kidney disease (CKD).

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

Randomised controlled trials (RCTs) comparing high-intensity statin therapy (atorvastatin 80 mg or rosuvastatin 20/40 mg) with moderate/mild statin treatment or placebo were derived from the databases (PubMed, Embase, Ovid, the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, and ISI Web of Knowledge).

OUTCOME MEASURE

Primary end points: clinical events (all-cause mortality, stroke, myocardial infarction and heart failure); secondary end points: serum lipid, renal function changes and adverse events.

RESULTS

A total of six RCTs with 10,993 adult patients with CKD were included. A significant decrease in stroke was observed in the high-intensity statin therapy group (RR 0.69, 95% CI 0.56 to 0.85). However, the roles of high-intensity statin in decreasing all-cause mortality (RR 0.85, 95% CI 0.67 to 1.09), myocardial infarction (RR 0.69, 95% CI 0.40 to 1.18) and heart failure (RR 0.73, 95% CI 0.48 to 1.13) remain unclear with low evidence. High-intensity statin also had obvious effects on lowering the LDL-C level but no clear effects on renal protection. Although pooled results showed no significant difference between the intervention and control groups in adverse event occurrences, it was still insufficient to put off the doubts that high-intensity statin might increase adverse events because of limited data sources and low quality evidences.

CONCLUSIONS

High-intensity statin therapy could effectively reduce the risk of stroke in patients with CKD. However, its effects on all-cause mortality, myocardial infarction, heart failure and renal protection remain unclear. Moreover, it is hard to draw conclusions on the safety assessment of intensive statin treatment in this particular population. More studies are needed to credibly evaluate the effects of high-intensity statin therapy in patients with CKD.

Statins and Cardiovascular Primary Prevention in CKD: A Meta-Analysis

BACKGROUND AND OBJECTIVES

Multiple meta-analyses of lipid-lowering therapies for cardiovascular primary prevention in the general population have been performed. Other meta-analyses of lipid-lowering therapies in CKD have also been performed, but not for primary prevention. This meta-analysis assesses lipid-lowering therapies for cardiovascular primary prevention in CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A systematic review and meta-analysis using a random-effects model was performed. MEDLINE was searched between January 2012 and September 2013 for new studies using predefined search criteria without language restrictions. A number of other sources including previously published meta-analyses were also reviewed. Inclusion criteria were randomized control trials of primary prevention with lipid-lowering therapy in non-end stage CKD.

RESULTS

Six trials were identified, five including patients with stage 3 CKD only. These studies included 8834 participants and 32,846 person-years of follow-up. All trials were post hoc subgroup analyses of statins in the general population. Statins reduced the risk of cardiovascular disease (the prespecified primary outcome) by 41% in stages 1-3 CKD compared with placebo (pooled risk ratio, 0.59; 95% confidence interval [95% CI], 0.48 to 0.72). For the secondary outcomes, the risk ratios were 0.66 (95% CI, 0.49 to 0.88) for total mortality, 0.55 (95% CI, 0.42 to 0.72) for coronary heart disease events, and 0.56 (95% CI, 0.28 to 1.13) for stroke. In study participants with stage 3 CKD specifically, the results were similar.

CONCLUSIONS

This meta-analysis suggests that the use of statins in CKD for primary prevention of cardiovascular disease is effective. These findings are consistent with recent guidance for the use of statins in all patients with CKD.

Simvastatin ameliorates low-dose streptozotocin-induced type 2 diabetic nephropathy in an experimental rat model

The present study aims to study the possible renal protective effect of simvastatin in the development and progression of type 2 diabetic nephropathy. A rat model of T2DN was induced by high-fat diet together with single low-dose of streptozotocin. The diabetic rats were either given treatment or vehicle control for 13 weeks to develop nephropathy. At the end of treatment, parameters of renal function were determined. Kidney samples were collected for histological studies and generated homogenates for biochemical analysis. In T2DN rats, severe hyperglycemia was developed, FBG were markedly elevated. Diabetes induced significant alterations in renal structure, such as severe reduction of glomerular tufts, increase in Bowman's spaces, thickening of GBM. In addition, and SCr, UAER and BUN are elevated, accompanied with reduction in UCr and CCr, indicating obvious renal failure. On the other hand, endogenous antioxidants SOD, GSH-Px were reduced, whereas MDA was increased. However, treatment of T2DN rats with simvastatin restored renal changes in different aspects. Our results showed that STZ-induced T2DN could be attenuated by simvastatin. The renoprotective effects of simvastatin was indicated by improvements in kidney function parameters, and was attributed by its lipid-lowering effect as well as its anti-oxidative stress, anti-inflammatory properties without having noticeable influence on glycemic control. Simvastatin ameliorates low-dose Streptozotocin-induced type 2 diabetic nephropathy in an experimental rat model.