Effect of fluvastatin on serum prohepcidin levels in patients with end-stage renal disease

Statin Therapy and Lipid Indices in Chronic Kidney Disease: A Systematic Review and Meta-analysis of Randomized Control Trials

BACKGROUND

Several studies have demonstrated the improvement in serum lipoproteins by statins in patients with Chronic Kidney Diseases (CKDs), including End-Stage Renal Disease (ESRD). However, the results of these studies are inconclusive.

AIM

We aimed to systematically investigate the effect of statins on lipid profiles of patients with CKD by performing a meta-analysis of Randomized Controlled Trials (RCTs).

METHODS

Major electronic databases (Scopus, MEDLINE/PubMed, and ISI Web of Science) were searched from inception to August, 2023, to find randomized controlled trials (RCTs) evaluating the effect of different statins on serum lipoproteins in CKD patients. Weighted Mean Difference (WMD) with 95% Confidence Intervals (CI) was used to estimate the effect size. Trial Sequential Analysis (TSA) was performed to confirm the robustness of the evidence.

RESULTS

A total of 18 publications were identified. It was found that statins reduced serum levels of Low-Density Lipoprotein (LDL)-C (WMD = -27.81 mg/dl, 95% CI = -34.47 to -21.15, P < 0.001) and total cholesterol (WMD = -25.44 mg/dl, 95% CI = -34.71 to -16.18, P < 0.001) in patients with CKD compared to the control group. Nonetheless, the effect of statins on High-Density Lipoprotein (HDL)-C (WMD = 0.57 mg/dl, 95% CI = -0.71 to 1.85, P = 0.38) and Triglyceride (TG) (WMD = -9.08 mg/dl, 95% CI = -22.22 to 2.06, P = 0.11) was not statistically significant. The results of TSA confirmed the robustness of the evidence and were consistent with the pooled effect size. The findings of subgroup analysis and time response analysis were also significant.

CONCLUSION

It was found that statin therapy reduced the levels of LDL-C and total cholesterol in patients with CKD.

The Link between Iron Turnover and Pharmacotherapy in Transplant Patients

Iron is a transition metal that plays a crucial role in several physiological processes. It can also exhibit toxic effects on cells, due to its role in the formation of free radicals. Iron deficiency and anemia, as well as iron overload, are the result of impaired iron metabolism, in which a number of proteins, such as hepcidin, hemojuvelin and transferrin, take part. Iron deficiency is common in individuals with renal and cardiac transplants, while iron overload is more common in patients with hepatic transplantation. The current knowledge about iron metabolism in lung graft recipients and donors is limited. The problem is even more complex when we consider the fact that iron metabolism may be also driven by certain drugs used by graft recipients and donors. In this work, we overview the available literature reports on iron turnover in the human body, with particular emphasis on transplant patients, and we also attempt to assess the drugs’ impact on iron metabolism, which may be useful in perioperative treatment in transplantology.

Improvement of clinical outcomes in patients undergoing peritoneal dialysis using hydroxymethylglutaryl-CoA reductase inhibitors: A systematic review and meta-analysis

BACKGROUND

It is unclear whether hydroxymethylglutaryl-CoA reductase inhibitor (statin) therapy decreases the risk of mortality and cardiovascular disease (CVD) in patients undergoing peritoneal dialysis (PD).

METHODS

We performed a literature search of PubMed, Cochrane Library, Embase, and other databases for research publications up to June 2022. The outcomes of interest were fatal and nonfatal CVDs, all-cause mortality, and changes in the biochemical profiles. Hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled and synthesized using a random-effects model. The certainty of the evidence was determined using Grading of Recommendations, Assessment, Development, and Evaluation.

RESULTS

Nine studies, including 2,933 patients undergoing PD, were included. Among them, three studies, including 2,099 patients, reported all-cause mortality, and three, including 1,571 patients, reported CVDs. In these patients, pooling results of two observational studies (very low-certainty evidence) showed that statin therapy significantly reduced CVDs (HR = 0.67; 95% CI = 0.54-0.84; p = 0.0004). Moreover, statin therapy was associated with significantly reduced low-density lipoprotein cholesterol, total cholesterol, and C-reactive protein levels (very low certainty of evidence). However, the effects of statin therapy on triglyceride, high-density lipoprotein, and albumin levels were not statistically significant.

CONCLUSION

Although statin therapy was associated with significantly reduced low-density lipoprotein cholesterol, total cholesterol, and C-reactive protein levels, the probable beneficial effect of statins on CVD risk in patients undergoing PD could not be concluded firmly. Additional high-quality studies are required to assess the potential beneficial effects of statin therapy in PD patients.

Statins Have an Anti-Inflammation in CKD Patients: A Meta-Analysis of Randomized Trials

Background

Persistent inflammation has been recognized as an important comorbid condition in patients with chronic kidney disease (CKD) and is associated with many complications, mortality, and progression of CKD. Previous studies have not drawn a clear conclusion about the anti-inflammatory effects of statins in CKD. This meta-analysis is aimed at assessing the anti-inflammatory effects of statins therapy in patients with CKD.

Methods

A comprehensive literature search was conducted in these databases (Medline, Embase, Cochrane library, and clinical trials) to identify the randomized controlled trials that assess the anti-inflammatory effects of statins. Subgroup, sensitivity, and trim-and-fill analysis were conducted to determine the robustness of pooled results of the primary outcome.

Results

25 eligible studies with 7921 participants were included in this meta-analysis. The present study showed that statins therapy was associated with a decreased C-reactive protein (CRP) (-2.06 mg/L; 95% CI: -2.85 to -1.27, p < 0.01). Subgroup, sensitivity, and trim-and-fill analysis showed that the pooled results of CPR were stable.

Conclusion

This meta-analysis demonstrates that statins supplementation has anti-inflammatory effects in patients with CKD. Statins exert an anti-inflammatory effect that is clinically important in improving complications, reducing mortality, and slowing progression in CKD. We believe that the benefits of statins to CKD are partly due to their anti-inflammatory effects. However, stains usually are prescribed in the CKD patients with dyslipidemia, whether statins can reduce inflammation in CKD patients with normal serum lipid needed to explore in the future. Therefore, we suggest that randomized clinical trials need to assess the effect of statins in CKD patients with normal serum lipid. Whether statins can be prescribed for aiming to inhibit inflammation in CKD also needed further study. Trial Registration. The study protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO); registration number: CRD42022310334.

Associations between Genetically Proxied Inhibition of Lipid-Lowering Drug Targets and Serum Micronutrients among Individuals of European Descent: A Mendelian Randomization Study

BACKGROUND

Limited and inconclusive data exist concerning the associations between lipid-lowering drugs and serum micronutrient concentrations.

METHODS

We conducted Mendelian randomization (MR) analyses to explore the associations between lipid-lowering drug targets and serum micronutrients. Single-nucleotide polymorphisms in genes encoding molecular targets of LDL cholesterol-lowering therapies were selected as instrumental variables for 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR; target of statins), proprotein convertase subtilisin/kexin type 9 (PCSK9; target of PCSK9 inhibitors), and Niemann-Pick C1-Like 1 (NPC1L1; target of ezetimibe). Exposure data were extracted from a published genome-wide association study (GWAS) of lipids in 188,577 European individuals, with outcome data obtained from the Integrative Epidemiology Unit (IEU) GWAS database (https://gwas.mrcieu.ac.uk). Overall, age and sex information were not calculable from the summary-level GWAS data. MR analyses were performed using the inverse-variance weighted method and MR sensitivity analysis methods.

RESULTS

We found genetically proxied inhibition of HMGCR to lower iron (effect, -0.16; 95% CI: -0.27, -0.06; P value = 0.003), zinc (effect, -0.83; 95% CI: -1.36, -0.31; P value = 0.002), magnesium (effect, -0.17; 95% CI: -0.27, -0.06; P value = 0.003), potassium (effect, -0.17; 95% CI: -0.27, -0.06; P value = 0.002), genetically proxied inhibition of NPC1L1 to increase calcium (effect, 0.28; 95% CI: 0.10, 0.46; P value = 0.003), retinol (effect, 0.25; 95% CI: 0.07, 0.44; P value = 0.01), and genetically proxied inhibition of PCSK9 to increase vitamin D (effect, 0.10; 95% CI: 0.07, 0.12; P value = 1.8 × 10-19). These associations were robust in MR sensitivity analyses. However, the associations between genetically proxied inhibition of HMGCR and NPC1L1 and the micronutrients were not consistent in multiple comparisons.

CONCLUSIONS

Our results provide evidence that statin use may lower serum concentrations of iron, zinc, magnesium, and potassium, PCSK9 inhibitors may increase serum vitamin D, and ezetimibe may increase serum calcium and retinol concentrations.

Non-Transferrin-Bound Iron in the Spotlight: Novel Mechanistic Insights into the Vasculotoxic and Atherosclerotic Effect of Iron

Significance: While atherosclerosis is an almost inevitable consequence of aging, food preferences, lack of exercise, and other aspects of the lifestyle in many countries, the identification of new risk factors is of increasing importance to tackle a disease, which has become a major health burden for billions of people. Iron has long been suspected to promote the development of atherosclerosis, but data have been conflicting, and the contribution of iron is still debated controversially. Recent Advances: Several experimental and clinical studies have been recently published about this longstanding controversial problem, highlighting the critical need to unravel the complexity behind this topic. Critical Issues: The aim of the current review is to provide an overview of the current knowledge about the proatherosclerotic impact of iron, and discuss the emerging role of non-transferrin-bound iron (NTBI) as driver of vasculotoxicity and atherosclerosis. Finally, I will provide detailed mechanistic insights on the cellular processes and molecular pathways underlying iron-exacerbated atherosclerosis. Overall, this review highlights a complex framework where NTBI acts at multiple levels in atherosclerosis by altering the serum and vascular microenvironment in a proatherogenic and proinflammatory manner, affecting the functionality and survival of vascular cells, promoting foam cell formation and inducing angiogenesis, calcification, and plaque destabilization. Future Directions: The use of additional iron markers (e.g., NTBI) may help adequately predict predisposition to cardiovascular disease. Clinical studies are needed in the aging population to address the atherogenic role of iron fluctuations within physiological limits and the therapeutic value of iron restriction approaches. Antioxid. Redox Signal. 35, 387-414.

Effect of atorvastatin on iron metabolism regulation in patients with chronic kidney disease - a randomized double blind crossover study

INTRODUCTION

To determine the effect of 6-month administration of atorvastatin on hepcidin and hemojuvelin levels, inflammatory parameters and iron metabolism in patients with chronic kidney disease (CKD) stages 3 and 4.

METHODS

Thirty six statin- and erythropoiesis-stimulating agent-naive patients with CKD stages 3 and 4 and LDL cholesterol ≥100 mg/dl received atorvastatin or placebo for two 6-month periods in a double blind, randomized crossover study. Hepcidin, hemojuvelin, hsCRP, IL-6, hemoglobin, red blood cell distribution width, iron, total iron binding capacity (TIBC), and unsaturated iron binding capacity (UIBC) were measured before and after each treatment period.

RESULTS

Hepcidin decreased (from 102 [307] to 63 [170] pg/ml (p > .001)) in the course of statin therapy but remained unchanged after placebo administration (173 [256] to 153 [204] pg/ml, respectively). Hemojuvelin did not change after either part of the study. Both IL-6 and hsCRP decreased following statin therapy (from 8.7 [12.0] to 8.1 [13.9] pg/ml; p = .04 and from 4.7 [4.0] to 4.0 [3.6] mg/l; p = .4, respectively), but did not change after placebo administration. Blood hemoglobin increased slightly but significantly after 6-month statin therapy (from 11.6 ± 1.6 to 11.9 ± 1.5 g/dl, p = .002), and was unchanged after placebo treatment. TIBC and UIBC increased significantly after 6-month statin therapy, and serum iron also tended to increase. The change of eGFR during the study did not differ between the two treatment periods.

CONCLUSIONS

Statin may have a small but potentially beneficial effect on serum hepcidin, which may lead to improvement of anemia control in CKD patients.

Serum hepcidin levels are associated with serum triglycerides and interleukin-6 concentrations in patients with end-stage renal disease

Hepcidin has emerged as a peptide with a key role in the regulation of iron homeostasis in patients with chronic kidney disease (CKD), having a strong dependence on inflammation. Recent studies reveal that hepcidin may be also associated with the progression of atherosclerosis. This study was performed to analyze the relation of hepcidin to markers of atherosclerosis and inflammation in patients on dialysis. A total of 90 individuals were enrolled. Sixty patients with end-stage renal disease, who were on hemodialysis (HD) (N = 30) and peritoneal dialysis (N = 30) were compared with 30 normal controls (NC). Age, body mass index, time on dialysis, serum lipids, C-reactive protein (CRP) and interleukin-6 (IL-6) were measured and analyzed in correlation with hepcidin concentration. It was found that patients on HD and peritoneal dialysis have significantly higher (P < 0.0001) levels of hepcidin, CRP and IL-6 than NC. Hepcidin in dialysis patients is significantly related to age (r = 0.373, P = 0.012), serum triglycerides (r = 0.401, P = 0.005), HDL-C (r = -0.268, P = 0.048), CRP (r = 0.436, P = 0.0007) and IL-6 (r = 0.569, P < 0.0001). In multiple regression analysis, hepcidin correlated independently with triglycerides (β = 0.402, P = 0.041) and IL-6 (β = 0.559, P = 0.006). Moreover, patients with high triglycerides in combination with high IL-6 levels have significantly increased concentrations of hepcidin than those with low triglycerides and low IL-6 levels (P < 0.0001). Elevated levels of hepcidin in patients with CKD on dialysis may be related to the occurrence of high triglycerides and high IL-6 serum concentrations. This probably suggests that hepcidin may play a role to the progression of atherosclerosis and inflammation, but this hypothesis should be further evaluated.

HMG CoA reductase inhibitors (statins) for dialysis patients

BACKGROUND

People with advanced kidney disease treated with dialysis experience mortality rates from cardiovascular disease that are substantially higher than for the general population. Studies that have assessed the benefits of statins (HMG CoA reductase inhibitors) report conflicting conclusions for people on dialysis and existing meta-analyses have not had sufficient power to determine whether the effects of statins vary with severity of kidney disease. Recently, additional data for the effects of statins in dialysis patients have become available. This is an update of a review first published in 2004 and last updated in 2009.

OBJECTIVES

To assess the benefits and harms of statin use in adults who require dialysis (haemodialysis or peritoneal dialysis).

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 29 February 2012 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs that compared the effects of statins with placebo, no treatment, standard care or other statins on mortality, cardiovascular events and treatment-related toxicity in adults treated with dialysis were sought for inclusion.

DATA COLLECTION AND ANALYSIS

Two or more authors independently extracted data and assessed study risk of bias. Treatment effects were summarised using a random-effects model and subgroup analyses were conducted to explore sources of heterogeneity. Treatment effects were expressed as mean difference (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes together with 95% confidence intervals (CI).

MAIN RESULTS

The risk of bias was high in many of the included studies. Random sequence generation and allocation concealment was reported in three (12%) and four studies (16%), respectively. Participants and personnel were blinded in 13 studies (52%), and outcome assessors were blinded in five studies (20%). Complete outcome reporting occurred in nine studies (36%). Adverse events were only reported in nine studies (36%); 11 studies (44%) reported industry funding.We included 25 studies (8289 participants) in this latest update; 23 studies (24 comparisons, 8166 participants) compared statins with placebo or no treatment, and two studies (123 participants) compared statins directly with one or more other statins. Statins had little or no effect on major cardiovascular events (4 studies, 7084 participants: RR 0.95, 95% CI 0.88 to 1.03), all-cause mortality (13 studies, 4705 participants: RR 0.96, 95% CI 0.90 to 1.02), cardiovascular mortality (13 studies, 4627 participants: RR 0.94, 95% CI 0.84 to 1.06) and myocardial infarction (3 studies, 4047 participants: RR 0.87, 95% CI 0.71 to 1.07); and uncertain effects on stroke (2 studies, 4018 participants: RR 1.29, 95% CI 0.96 to 1.72).Risks of adverse events from statin therapy were uncertain; these included effects on elevated creatine kinase (5 studies, 3067 participants: RR 1.25, 95% CI 0.55 to 2.83) or liver function enzymes (4 studies, 3044 participants; RR 1.09, 95% CI 0.41 to 1.25), withdrawal due to adverse events (9 studies, 1832 participants: RR 1.04, 95% CI 0.87 to 1.25) or cancer (2 studies, 4012 participants: RR 0.90, 95% CI 0.72 to 1.11). Statins reduced total serum cholesterol (14 studies, 1803 participants; MD -44.86 mg/dL, 95% CI -55.19 to -34.53) and low-density lipoprotein cholesterol (12 studies, 1747 participants: MD -39.99 mg/dL, 95% CI -52.46 to -27.52) levels. Data comparing statin therapy directly with another statin were sparse.

AUTHORS' CONCLUSIONS

Statins have little or no beneficial effects on mortality or cardiovascular events and uncertain adverse effects in adults treated with dialysis despite clinically relevant reductions in serum cholesterol levels.

A meta-analysis of the role of statins on renal outcomes in patients with chronic kidney disease. Is the duration of therapy important?

INTRODUCTION

The efficacy of statin treatment in chronic kidney disease (CKD) patients remains controversial. Therefore, we performed a meta-analysis to investigate whether statins modulate renal function in patients with CKD.

METHODS

Data from Scopus, PubMed, Web of Science, and the Cochrane Central Register of randomized controlled trials for years 1966-December 2012 were searched for appropriate studies.

RESULTS

Twenty trials with 6452 CKD subjects randomized to receive either statin or placebo were included. Statin therapy significantly influenced high sensitivity C-reactive protein levels in patients on or off dialysis [-0.28 mg/dl, 95%CI: -0.93 to -0.37; p<0.05 and -0.46 mg/dl, 95%CI: -0.87 to -0.05; p=0.03], respectively], urinary protein (-0.77 g/24 h, 95%CI: -1.24 to -0.29, p<0.02; this effect persisted for treatment ≤12 months), and serum creatinine but only for long-term therapy (3 years) (-0.65 mg/dl, 95%CI: -1.00 to -0.30; p=0.0003). The summary for standardized effect size of mean differences of glomerular filtration rate was 0.29 ml/min/1.73 m(2) (95%CI: 0.01 to 0.58; p=0.04), and depended on treatment duration - a significant increase was observed for between 1 and 3 years of statin therapy (0.50 ml/min/1.73 m(2), 95%CI: 0.40 to 0.60; p<0.0001), with no significant increase for both ≤1 and >3 years of the therapy.

CONCLUSION

Statins might exert significant renoprotective effects in CKD patients; however, benefit may depend on the duration of treatment. This is an issue that warrants more definitive investigation. More studies are necessary in dialysis patients to credibly evaluate the renal effects of statin therapy.

Renal anaemia and EPO hyporesponsiveness associated with vitamin D deficiency: the potential role of inflammation

Resistance to erythropoiesis-stimulating agents (ESAs) has been observed in a considerable proportion of patients with chronic kidney disease (CKD) and it is reportedly associated with adverse outcomes, such as increased cardiovascular morbidity, faster progression to end-stage renal disease (ESRD) and all-cause mortality. The major causes of ESA resistance include chronic inflammation producing suppressive cytokines of early erythroid progenitor proliferation. In addition, pro-inflammatory cytokines stimulate hepcidin synthesis thus reducing iron availability for late erythropoiesis. Recent studies showing an association in deficiencies of the vitamin D axis with low haemoglobin (Hb) levels and ESA resistance suggest a new pathophysiological co-factor of renal anaemia. The administration of either native or active vitamin D has been associated with an improvement of anaemia and reduction in ESA requirements. Notably, these effects are not related to parathyroid hormone (PTH) values and seem to be independent on PTH suppression. Another possible explanation may be that calcitriol directly stimulates erythroid progenitors; however, this proliferative effect by extra-renal activation of 1α-hydroxylase enzyme is only a hypothesis. The majority of studies concerning vitamin D deficiency or supplementation, and degree of renal anaemia, point out the prevalent role of inflammation in the mechanism underlying these associations. Immune cells express the vitamin D receptor (VDR) which in turn is involved in the modulation of innate and adaptive immunity. VDR activation inhibits the expression of inflammatory cytokines in stromal and accessory cells and up-regulates the lymphocytic release of interleukin-10 (IL-10) exerting both anti-inflammatory activity and proliferative effects on erythroid progenitors. In CKD patients, vitamin D deficiency may stimulate immune cells within the bone marrow micro-environment to produce cytokines, inducing impaired erythropoiesis. Immune activation involves the reticuloendothelial system, increasing hepcidin synthesis and functional iron deficiency. Consequences of this inflammatory cascade are erythropoietin (EPO) resistance and anaemia. Given the key role of inflammation in the response to EPO, the therapeutic use of agents with anti-cytokines properties, such as vitamin D and paricalcitol, may provide benefit in the prevention/treatment of ESA hyporesponsiveness.

The statin-iron nexus: anti-inflammatory intervention for arterial disease prevention

OBJECTIVES

We postulated the existence of a statin-iron nexus by which statins improve cardiovascular disease outcomes at least partially by countering proinflammatory effects of excess iron stores.

METHODS

Using data from a clinical trial of iron (ferritin) reduction in advanced peripheral arterial disease, the Iron and Atherosclerosis Study, we compared effects of ferritin levels versus high-density lipoprotein to low-density lipoprotein ratios (both were randomization variables) on clinical outcomes in participants receiving and not receiving statins.

RESULTS

Statins increased high-density lipoprotein to low-density lipoprotein ratios and reduced ferritin levels by noninteracting mechanisms. Improved clinical outcomes were associated with lower ferritin levels but not with improved lipid status.

CONCLUSIONS

There are commonalities between the clinical benefits of statins and the maintenance of physiologic iron levels. Iron reduction may be a safe and low-cost alternative to statins.

Effect of statins on chronic inflammation and nutrition status in renal dialysis patients: a systematic review and meta-analysis

AIM

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) may have an adjunctive effect on chronic inflammation and nutrition status in renal dialysis patients. Therefore, we performed a systematic review of randomized controlled trials to assess the effect of statins on chronic inflammation and nutrition status in dialysis patients.

METHODS

The randomized controlled trials (RCTs) of statins versus placebo or no treatment for renal dialysis patients were searched from PubMed, EMbase and Cochran Central Register of Controlled Trials. We screened relevant studies according to predefined inclusion and exclusion criteria, evaluated the quality of the included studies, and performed meta-analyses by using the Cochrane Collaboration's Revman 5.1 software.

RESULTS

We identified nine trials including 3098 patients. Meta-analysis showed statins can significantly decrease the serum C-reactive protein (CRP) (SMD, -0.54; 95% confidence interval (CI), -1.04 to -0.05; P = 0.03) and high sensitivity CRP (hs-CRP) level (SMD, -0.72; 95% CI, -1.14 to -0.31; P = 0.0007) of dialysis patients compared with that of the control group. However, statins did not differ significantly from the control group in increasing the serum Alb level (SMD, -0.13; 95% CI, -0.42 to 0.15; P = 0.37).

CONCLUSIONS

Statins can improve the chronic inflammation status reflected by the decreasing of serum CRP and hs-CRP levels, whereas there is no conclusive evidence that it can improve the nutrition status. However, this result needs to be further confirmed in more high-quality randomized clinical trials.

Might the beneficial effects of statin drugs be related to their action on iron metabolism?

Although the cholesterol-heart hypothesis is often regarded as a dogmatic belief, controversy continues to surround the aetiology and pathogenesis of atherosclerosis. In fact, lowering cholesterol with statin drugs has been shown to reduce cardiovascular risk. However, statins have pleiotropic effects independent of their capacity to lower cholesterol. We highlight that statin drugs exert an important action on iron metabolism, which in turn may prevent progression and destabilization of atherosclerotic plaque. If it is found that the effect of statins on iron metabolism is a mechanism of their beneficial action, this consequence of statin use can be clinically replicated by other methods, such as controlled reduction of body iron stores. This might allow the use of lower doses or even obviate the use of statins in primary cardiovascular prevention, and therefore avoid the side effects and expense of these drugs.

Endogenous erythropoietin and the association with inflammation and mortality in diabetic chronic kidney disease

BACKGROUND AND OBJECTIVES

Anemia and inflammation are prevalent in diabetic patients with chronic kidney disease (CKD). The role of endogenous erythropoietin (EPO) in the pathophysiology of anemia in chronic diseases and its relationship to clinical outcomes remain uncertain. In this cohort study, we aimed to identify factors associated with endogenous EPO levels and investigate their relation to all-cause mortality.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Between 2004 and 2005, 215 patients with type 2 diabetes were enrolled. Exclusion criteria included stage renal disease ESRD and any form of anemia therapy. The association of EPO levels with clinical and laboratory variables was investigated by linear regression modeling. Predictors of all-cause mortality were evaluated by Cox proportional hazards analyses.

RESULTS

Patients (median age, 67 years; 52% men; median duration of diabetes, 10 years; median estimated GFR, 49 ml/min per 1.73 m²) were followed for up to 7.0 years. Forty-one patients died. Elevated EPO levels were independently associated with elevated C-reactive protein, low ferritin, and hypertension, in a multivariate model that also included age, cardiovascular disease, kidney function, albumin, cholesterol, and hemoglobin. Higher EPO levels were independently predictive for mortality, as were age, low levels of albumin, and cardiovascular disease.

CONCLUSIONS

In diabetic patients with CKD, elevated endogenous EPO levels were predictive for mortality and were related mainly to markers of inflammation, independent of kidney function, and despite low hemoglobin levels. Understanding the phenomenon of EPO resistance and iron dysregulation caused by inflammation is crucial for effective and safe treatment of anemia in patients with CKD.

Renal anemia of inflammation: the name is self-explanatory

BACKGROUND

Anemia is inevitable as chronic kidney disease (CKD) advances. With the advent of erythropoietin-stimulating agents (ESAs), considerable improvement has been achieved in the management of anemia. However, some patients show a reduced response to ESAs.

METHODS

Many factors affect the response to ESA treatment. CKD is now considered as an inflammatory disorder and this understanding led to the recognition of the central role of inflammation in ESA resistance. Inflammation is related to untoward outcomes, including atherosclerosis and anemia, in the CKD population. Furthermore, recognition of deleterious effects of proinflammatory markers at different levels of erythropoiesis led to a change in the name of 'anemia of chronic disease' to anemia of inflammation.

RESULTS

The discovery of hepcidin as the major controller of iron metabolism in anemia of inflammation answered many questions regarding the interaction of erythropoietin, iron and bone marrow. Hepcidin production in the liver is driven by three major factors: inflammation, iron overload and anemia/hypoxia. Hepcidin levels are increased in patients with CKD due to the interaction of many factors; a comprehensive understanding of these pathways is thus critical in the effort to alleviate anemia of inflammation and ESA resistance.

CONCLUSION

In this review, we discussed the epidemiology, determinants and consequences of anemia of inflammation in CKD patients with special emphasis on the central role of hepcidin along with molecular pathways driving its production.