Functional erythropoietin deficiency in patients with Type 2 diabetes and anaemia

Targeting PKC alleviates iron overload in diabetes and hemochromatosis

Diabetes is one of the most prevalent chronic diseases worldwide. Iron overload increases the incidence of diabetes and aggravates diabetic complications that cause mortality. Reciprocally, diabetes potentially promotes body iron loading, but the mechanism remains not well understood. In this study, we demonstrated systemic iron excess and the upregulation of iron exporter ferroportin (Fpn) in the enterocytes and macrophages of multiple diabetic mouse models. Increased Fpn expression and iron efflux was also seen in the enterocytes of type 2 diabetic human patients. We further showed that protein kinase C (PKC), which is activated in hyperglycemia, was responsible for the sustained membrane expression of Fpn in physiological and in diabetic settings. For the first time, we identified that PKCs were novel binding proteins and positive regulators of Fpn. Mechanistically, hyperactive PKC promoted exocytotic membrane insertion while inhibited the endocytic trafficking of Fpn in the resting state. PKC also protected Fpn from internalization and degradation by its ligand hepcidin dependent on decreased ubiquitination and increased phosphorylation of Fpn. Importantly, the loss-of-function and pharmacological inhibition of PKC alleviated systemic iron overload in diabetes and hemochromatosis. Our study thus highlights PKC as a novel target in the control of systemic iron homeostasis.

Pathophysiology of Red Blood Cell Dysfunction in Diabetes and Its Complications

Diabetes Mellitus (DM) is a complex metabolic disorder associated with multiple microvascular complications leading to nephropathy, retinopathy, and neuropathy. Mounting evidence suggests that red blood cell (RBC) alterations are both a cause and consequence of disturbances related to DM-associated complications. Importantly, a significant proportion of DM patients develop varying degrees of anemia of confounding etiology, leading to increased morbidity. In chronic hyperglycemia, RBCs display morphological, enzymatic, and biophysical changes, which in turn prime them for swift phagocytic clearance from circulation. A multitude of endogenous factors, such as oxidative and dicarbonyl stress, uremic toxins, extracellular hypertonicity, sorbitol accumulation, and deranged nitric oxide metabolism, have been implicated in pathological RBC changes in DM. This review collates clinical laboratory findings of changes in hematology indices in DM patients and discusses recent reports on the putative mechanisms underpinning shortened RBC survival and disturbed cell membrane architecture within the diabetic milieu. Specifically, RBC cell death signaling, RBC metabolism, procoagulant RBC phenotype, RBC-triggered endothelial cell dysfunction, and changes in RBC deformability and aggregation in the context of DM are discussed. Understanding the mechanisms of RBC alterations in DM provides valuable insights into the clinical significance of the crosstalk between RBCs and microangiopathy in DM.

New Approaches to Diabetic Nephropathy from Bed to Bench

Diabetic nephropathy (DN) is the main cause of end-stage kidney disease (ESKD). DN-related ESKD has the worst prognosis for survival compared with other causes. Due to the complex mechanisms of DN and the heterogeneous presentations, unmet needs exist for the renal outcome of diabetes mellitus. Clinical evidence for treating DN is rather solid. For example, the first Kidney Disease: Improving Global Outcomes (KDIGO) guideline was published in October 2020: KDIGO Clinical Practice Guideline for Diabetes Management in Chronic Kidney Disease. In December of 2020, the International Society of Nephrology published 60 (+1) breakthrough discoveries in nephrology. Among these breakthroughs, four important ones after 1980 were recognized, including glomerular hyperfiltration theory, renal protection by renin-angiotensin system inhibition, hypoxia-inducible factor, and sodium-glucose cotransporter 2 inhibitors. Here, we present a review on the pivotal and new mechanisms of DN from the implications of clinical studies and medications.

Anemia in Diabetes and Pre-Diabetes with Normal Kidney Function: Prevalence and Clinical Outcomes

OBJECTIVE

Anemia is a known complication of diabetes mellitus (DM); however, its prevalence and prognostic relevance in patients with DM and pre-DM with normal kidney function is not well-defined. This study assessed the prevalence of anemia in DM and pre-DM patients and evaluated its association with clinical outcomes during 4-years' follow-up.

METHODS

This retrospective analysis included patients with DM and pre-DM referred to the Meir Medical Center Endocrine Institute during 2015. Patients with estimated glomerular filtration rate (eGFR) <60 ml/min or other recognized cause of anemia were excluded. The risk of developing microvascular or macrovascular complications, or death during four years follow-up was determined.

RESULTS

A total of 622 patients (408 with DM and 214 with pre-DM) were included. Mean age was 64±10.6 years, and 70% were women. Baseline HbA1c was 7.1±1.7% and eGFR was 86.1±15.3 ml/min. At inclusion 77 (19%) patients with DM and 23 (11%) with pre-DM, had anemia (hemoglobin 11.9±0.8 and 11.8±0.8 g/dl, respectively) vs. normal hemoglobin levels of 13.8±0.9 and 13.7±0.9 g/dl, respectively in the others. Multivariable analysis demonstrated an inverse correlation between baseline hemoglobin (as a continuous variable) and mortality (P=0.035), microvascular complications (P=0.003) and eGFR decline (P<0.001), but not with macrovascular complications (P=0.567).

CONCLUSION

This study found a significant prevalence of anemia unrelated to renal failure, both in DM and pre-DM. Anemia in these patients is associated with development of microvascular complications, eGFR decline and mortality. These results underscore the need for intensive lifestyle and pharmacological interventions among these patients.

Magnitude and factors associated with anemia among diabetic patients in Ethiopia: A systematic review and meta-analysis

Background:

In Ethiopia, diabetes is estimated to affect about half a million people. About 35% of individuals with diabetes are complicated by microvascular diseases like retinopathy, nephropathy, cardiovascular, and anemia. Even though there are some studies conducted on prevalence and associated factors of anemia in diabetic patients, their findings were variable. Therefore, this meta-analysis is aimed to determine the pooled prevalence and factors associated with anemia among diabetic patients.

Methods:

PubMed, CINAHL, POPLINE, ScienceDirect, African Journals Online, and Google Scholar were systematically searched to identify related studies. The heterogeneity of studies was assessed using Cochran’s Q test and I² tests. A random-effects model was used to estimate the pooled prevalence of anemia among diabetic patients in Ethiopia. Publication bias was evaluated by employing Egger’s tests.

Results:

After reviewing 503 articles, 6 articles fulfilled inclusion criteria and remained for the final meta-analysis. The pooled prevalence of anemia among diabetic patients was 24.81% (95% confidence interval: 19.38–30.25). Age greater than 60 years old (pooled odds ratio, 95% confidence interval: 3.73 (2.23–6.77)), glomerular filtration rate less than 60 mL/min/1.73 m² (pooled odds ratio, 95% confidence interval: 12.65 (8.71–18.37)), and being diabetic for more than 10 years (pooled odds ratio, 95% confidence interval: 10.21 (7.00–15.04)) were found to be determinants of anemia among diabetic patients in Ethiopia.

Conclusion:

Overall, one in four diabetic patients develops anemia in Ethiopia. Age, glomerular filtration rate, and duration of being diabetic are factors significantly associated with the occurrence of anemia in diabetic patients.

Anaemia and its associated factors among diabetes mellitus patients in Ethiopia: A systematic review and meta-analysis

Introduction

Anaemia is common but often overlooked in diabetes mellitus (DM) patients. There is also no official nationwide survey registry that estimated the prevalence of anaemia in DM patients in Ethiopia. Therefore, the main aim of this study is to determine the countrywide pooled prevalence and associated factors of anaemia in DM patients.

Methods

This systematic review and meta‐analysis were conducted as per the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. STATA 11 software was used for all statistical analysis. Random effects model was used to estimate the pooled prevalence of anaemia and associated factors at a 95% confidence interval (CI) with its respective odds ratio (OR). Subgroup analysis and egger test were used to determine heterogeneity and publication bias, respectively.

Results

Nine articles were included in this systematic review and meta‐analysis with a total of 2889 DM patients. The pooled prevalence of anaemia among DM patients in Ethiopia was 22.11% (95% CI: 15.83–28.39) I² = 94.8%. The prevalence of anaemia in type I and type II DM patients was (16.78% [95% CI: 11.53–22.04]) and (31.12% [95% CI; 9.66–52.58]), respectively. The prevalence of anaemia was higher among male (36.72% [95% CI: 22.58–50.87] I² = 97.6%) than female (27.51% [95% CI: 16.12–38.90] I² = 96.3%). Moreover, the odds of anaemia were higher among patients with age ˃ 60 (OR = 2.98; 95% CI: 1.83, 4.87), low estimated glomerular filtration rate (eGFR) (OR = 8.59; 95% CI: 4.76, 15.57), and duration of illness ≥5 years (OR = 2.66; 95%: 1.38, 5.13).

Conclusions

The result of this review implies that anaemia is a moderate public health problem among DM patients in Ethiopia. Older age, poor glycemic control, low eGFR and longer duration of illness were found to be the contributing factors for the development of anaemia in DM patients. Therefore, by considering the negative impact of anaemia, it is important to include anaemia screening into routine assessment of DM‐related complications targeting patients with older age, poor glycemic control, low eGFR, and longer duration of illness to reduce the magnitude of the problem.

The magnitude of anemia and associated factors among adult diabetic patients in Tertiary Teaching Hospital, Northern Ethiopia, 2019, cross-sectional study

Background

Patients with Diabetic Mellitus are at higher risk of different complications. Many previous studies show that anemia among diabetic patients is poorly diagnosed.

Objective

This study aimed to assess the magnitude and associated factors of anemia among adult diabetes patients having regular follow up at the diabetic clinic of Ayder Comprehensive Specialized Hospital, Tigray, 2018/19.

Methods

This study was conducted the Diabetic clinic of Ayder comprehensive specialized hospital, Tigray regional state, Northern Ethiopia from January to March 2019. A systematic random sampling technique was used to select study participants. About 5 ml of venous blood was collected by experienced laboratory technologists under a complete aseptic technique. Two ml of the venous blood was used for hemoglobin determination. And three ml of the venous blood was used without any anticoagulant for creatinine determination. The association of variables was assessed using bivariate and multivariable analysis in the logistic regression model with p-value, odds ratio, and 95% CI in the SPSS version 24 software.

Results

From a total of 262 diabetes patients, forty-seven (17.9%) were found to be anemic (6.7% males and 11.5% females). Among the related factors, residency (Adjusted Odds Ratio, 7.69, 95% CI, 2.060, 28.69, p = 0.002,), age of the patients (Adjusted Odds Ratio, 4.007, 95%CI, 1.53–10.51, p = 0.005,) and sex (Adjusted Odds Ratio, 3.434, 95% CI, 1.582, 7.458, p = 0.042,) were significantly associated with anemia.

Conclusion

According to this study, the magnitude of anemia is high among diabetic patients. Occupation of the participants, residency, HIV status, being female, and age was significantly associated with anemia.

Sitagliptin on Carotid Intima-Media Thickness in Type 2 Diabetes Mellitus Patients and Anemia: A Subgroup Analysis of the PROLOGUE Study

Introduction

Randomized clinical trials have not shown an additional clinical benefit of sitagliptin treatment over conventional treatment alone. However, studies of sitagliptin treatment have not examined the relationship between anemia and treatment group outcomes.

Methods

The PROLOGUE study is a prospective clinical trial of 442 participants with type 2 diabetes mellitus (T2DM) randomized to sitagliptin treatment or conventional treatment which showed no treatment differences [Estimated mean (± standard error) common carotid intima-media thickness (CIMT) was 0.827 ± 0.007 mm and 0.837 ± 0.007 mm, respectively, with a mean difference of -0.009 mm (97.2% CI −0.028 to 0.011, p = 0.309) at 24 mo of follow-up]. This is a post hoc subanalysis using data obtained from the PROLOGUE study; the study population was divided into anemic groups (n = 94) and nonanemic group (n = 343) based on hemoglobin level. And we analyzed for the changes in each CIMT parameter from baseline to 24 months in subgroups.

Results

The treatment group difference in baseline-adjusted mean common carotid artery- (CCA-) IMT at 24 months was −0.003 mm (95% CI −0.022 to 0.015, p = 0.718) in the nonanemic subgroup and −0.007 mm (95% CI −0.043 to 0.030, p = 0.724) in the anemic subgroup. Although there were no significant differences in the other CIMT parameters between the treatment groups in the anemic subgroup, the changes in mean and max ICA-IMT at 24 months in the nonanemic subgroup were significantly lower in the sitagliptin group than the conventional group [−0.104 mm (95% CI −0.182 to −0.026), p = 0.009 and −0.142 mm (−0.252 to −0.033), p = 0.011, respectively].

Conclusion

These data suggest that nonanemia may indicate a potentially large subgroup of those with T2DM patients that sitagliptin therapy has a better antiatherosclerotic effect than conventional therapy. Further research is needed to confirm these preliminary observations.

Red Blood Cells Aggregation in the Patients with Type 2 Diabetes and T2D Associated Anemia, a Case Control Study in Bangladesh

Background and Aims: Type 2 Diabetes (T2D) is a chronic metabolic disorder. Nowadays the number of people with diabetes mellitus is quadrupling in the world as well as in Bangladesh. It is related to different types of disease morbidity and sociodemographic parameters. The present study aimed to investigate the association of RBC aggregation (measured by ESR level) with T2D and T2D associated anemia.

Material and method: A total of 234 subjects were included in the study. Sociodemographic and anthropometric information about study subjects were collected using a standard questionnaire. Blood samples were tested for random blood glucose levels, Hb percentage, and ESR. Association of these data with metabolic disorders was analyzed by statistical analysis software, SPSS.

Results: This study provides a piece of evidence that anemia is highly prevalent in T2D patients than the healthy control subjects in Bangladesh (59.1% vs 22.5%; P value <0.001). The ESR values were significantly elevated in T2D patients as well as anemic and aged subjects (P value <0.001).

Conclusion: The study thus suggests that anemia was prevalent in T2D patients in Bangladesh. The RBC aggregation was significantly elevated in patients with T2D as well as anemia, indicating increased inflammatory response in these diseases.

Potential Biomarkers in Diabetic Retinopathy

BACKGROUND

Diabetic retinopathy is one of the important complications of diabetes. In major cases, diabetic retinopathy is unnoticed until the irreversible damage to eye occurs and leads to blurred vision and, eventually, blindness.

OBJECTIVE

The pathogenesis and diagnosis of diabetic retinopathy are very complex and not fully understood. Currently, well-established laser techniques and medications are available, but these treatment options have their own shortcomings on biological systems. Biomarkers can help to overcome this problem due to easy, fast and economical options for diagnosis of diabetic retinopathy.

METHODS

The search terms used were "Diabetic retinopathy", "Biomarkers in diabetic retinopathy", "Novel biomarkers in diabetic retinopathy" and "Potential biomarkers of diabetic retinopathy" by using different scientific resources and databases like EBSCO, ProQuest, PubMed and Scopus. Eligibility criteria included biomarkers involved in diabetic retinopathy in the detectable range. Exclusion criteria included the repetition and duplication of the biomarker in diabetic retinopathy.

RESULTS

Current review and literature study revealed that biomarkers of diabetic retinopathy can be categorized as inflammatory: tumor necrosis factor-α, monocyte chemoattractant protein-1, transforming growth factor- β; antioxidant: nicotinamide adenine dinucleotide phosphate oxidase; nucleic acid: poly ADP ribose polymerase- α, Apelin, Oncofetal; enzyme: ceruloplasmin, protein kinase C; and miscellaneous: erythropoietin. These biomarkers have a great potential in the progression of diabetic retinopathy hence can be used in the diagnosis and management of this debilitating disease.

CONCLUSION

Above mentioned biomarkers play a key role in the pathogenesis of diabetic retinopathy; hence they can also be considered as potential targets for new drug development.

Anemia in patients of diabetic kidney disease

Anemia is the major complication resulting from chronic kidney disease (CKD) and also a risk factor for cardiovascular events and a poor quality of life (QoL). Diabetic kidney disease (DKD) is the major cause of CKD. Initially, insulin resistance has been reported to increase erythropoiesis, but it might be a minor issue. DKD-related anemia developed earlier and was more severe than non-DKD-related anemia based on more complicated mechanisms, including greater bleeding tendency associated with antiplatelet effect, less O2 sensing due to autonomic neuropathy or renin-angiotensin-aldosterone system inhibitor use, inhibitory effect of inflammatory cytokines, urinary loss of erythropoietin (EPO), and poor response to EPO. In DKD patients, prompt correction of anemia allows for a better cardiovascular outcome and QoL, which are similar to the promising effect of anemia correction in CKD patients. However, current evidence recommended that the avoidance of a high or normalized hemoglobin (Hb) level has been suggested in the treatment of anemia in DKD patients. Despite that EPO has a pleotropic effect on renal protection from animal studies, the renal benefit was less evident in CKD and DKD patients. Recently, the antidiabetic agent, sodium glucose cotransporter-2 inhibitors (SGLT2i), has been reported to exhibit the renal benefits due to the tubulo-glomerular feedback in addition to sugar control. It may also be due to less renal ischemic through higher EPO levels, followed by higher Hb levels. More studies are needed to clarify the link between the renal benefit of SGLT2i and EPO production.

Prevalence of anemia in diabetic adult outpatients in Northeast Ethiopia

Background

Anemia is a common finding in patients with diabetes, even in the absence of kidney disease and is a risk factor for adverse outcomes, including all-cause and cardiovascular mortality. Despite this, relatively little is known about the burden of anemia among adults with diabetes in sub-Saharan Africa. The aim of this study was to determine the prevalence of anemia and its association with renal disease among diabetic adult outpatients attending a hospital in Northeast Ethiopia.

Methods

A cross-sectional study was conducted among 412 diabetic adults at the diabetes clinic of Dessie Referral hospital in Northeast Ethiopia, from January to April 2018. Each patient provided a blood sample for hemoglobin and serum creatinine levels and urine for albuminuria. Anemia was defined by World Health Organization criteria (<13 g/dl for men and <12 g/dl for women). Glomerular filtration rate (GFR) was estimated using the 4-variable Modification of Diet in Renal Disease (MDRD) equation. Chronic kidney disease (CKD) was classified into 5 stages based on the eGFR and albuminuria.

Results

Anemia was present in 26.7% of the participants, and CKD in 43.0%. Anemia was more prevalent in patients with CKD (39.5%) than those without CKD (17.0%; P < 0.001). The prevalence of anemia increased with stage of CKD, from 22.6% at stage 1 to 100% at stage 4. Fifteen percent of the patients had anemia below the treatment threshold of 11 g ⁄dl. In multivariate analysis, older age (AOR = 2.41, 95% CI 1.11–5.21); type 2 diabetes (AOR = 2.40, 95% CI 1.14–5.08); presence of hypertension (AOR = 3.78, 95% CI 1.35–10.57); high systolic BP (AOR = 1.05, 95% CI 1.02–1.08); serum creatinine (AOR = 12.80, 95% CI 3.90–87.98) and low GFR (AOR = 9.50, 95% CI 4.05–22.28) were independently associated with greater odds for the presence of anemia

Conclusions

Anemia is commonly present among diabetic adults attending our diabetes outpatient clinic in Northeast Ethiopia, including those without kidney disease. Our findings highlight the need for incorporating anemia screening into routine diabetes care to enable early detection and treatment of anemia and hence improve the overall care of patients with diabetes.

Glycation of hemoglobin leads to the immunogenicity as a result of neo-epitope generation

Non-enzymatic glycation occurs rapidly which ultimately leads to the formation of advanced glycation endproducts (AGEs). These AGEs have shown to associated with the development of many diseases such as diabetes-mellitus. This study is focused on immunological characterization of glycated-Hb induced by d-ribose. Here, we analysed the immunogenicity of glycated-Hb by direct binding and competitive inhibition ELISA. Direct binding ELISA confirmed that glycated-Hb was highly immunogenic and induced high titre antibodies as compared to native-Hb. The antigen binding specificity and cross reactivity of these antibodies were also screened by competitive inhibition ELISA. The IgG from rabbit sera showed enhanced binding of glycated-Hb than native-Hb. Thus, it is possible that alterations in Hb induced by d-ribose could have generated highly immunogenic neoepitopes. Moreover, induced antibodies were also found to cross-react with other modified/native proteins. On the basis of the results of this study, we presume that this type of structural perturbations in Hb in vivo by d-ribose might take place in untreated diabetic condition that could induce such type of immunogenic auto-antibodies. Furthermore, increased level of these auto-antibodies could serve as a biomarker in diabetes and its progression.

Diabetes and Anemia: International Diabetes Federation (IDF) - Southeast Asian Region (SEAR) position statement

Anemia is often associated with diabetes mellitus and is known to intensify the risk of developing diabetes-related microvascular and macrovascular complications. There is paucity in understanding of co-existence of these conditions, especially in Southeast Asian countries. Iron and/or erythropoietin deficiencies are the major causes of anemia in diabetes, and diabetic kidney disease plays a key role. Patients with diabetes need to be screened for anemia along with other risk factors and anemia should be corrected appropriately to improve overall clinical outcomes. This position statement aims to provide a comprehensive overview and an algorithm for appropriate management of anemia in patients with diabetes.

Erythropoietin concentration in acute kidney injury is associated with insulin-like growth factor-binding protein-1

AIM

Erythropoietin (EPO) production is stimulated by hypoxia in the kidney. Ischaemic injury plays a crucial role in the pathogenesis of acute kidney injury (AKI). However, EPO concentrations in critically ill patients complicated with AKI have not been evaluated sufficiently. This study was conducted to clarify the factors associated with plasma EPO concentrations in AKI.

METHODS

This study prospectively enrolled 98 critically ill adult patients treated at the adult mixed ICU. Plasma EPO, insulin-like growth factor-binding protein-1 (IGFBP-1), neutrophil gelatinase-associated lipocalin (NGAL), interleukin-6 (IL-6) and urinary N-acetyl-β-D-glucosaminidase (NAG) were measured on ICU admission.

RESULTS

Acute kidney injury occurred in 42 (42.9%) patients. Significantly higher plasma EPO in the AKI group was detected than in the non-AKI group (16.13 (9.87-28.47) mIU/mL versus 27.81 (10.16-106.02) mIU/mL, P < 0.05). Plasma IGFBP-1 in the AKI group was also significantly higher than in the non-AKI group (19 208 (8820-50 780) pg/mL versus 63 199 (25 289-147 489) pg/mL, P < 0.05). Plasma EPO concentration was negatively correlated with haemoglobin in the non-AKI group with statistical significance, but not in the AKI group. Multiple logistic regression analysis revealed that plasma EPO in the AKI group was associated significantly with plasma IGFBP-1 and complication of diabetes mellitus, but not the haemoglobin concentration, partial pressure of arterial oxygen (PaO2 ), and IL-6.

CONCLUSIONS

Not low arterial oxygen tension, haemoglobin concentration, and inflammation evaluated by IL-6 but plasma IGFBP-1 was significantly associated with plasma EPO concentration in AKI, suggesting an unknown mechanism related to systemic stress conditions for EPO regulation in AKI.

Less known pathophysiological mechanisms of anemia in patients with diabetic nephropathy

Diabetes mellitus (DM) is currently considered a modern global epidemic, and diabetic nephropathy (DN) is the most common cause of chronic kidney disease (CKD). Anemia is one of the most significant complications of CKD, and it is mainly attributed to insufficient erythropoietin (EPO) production. However, anemia develops earlier in the course of CKD among patients with DM, and the severity of anemia tends to be more marked in these patients compared to nondiabetic subjects, regardless of the stage of CKD. In this review, we focus on the "less known" complex interacting mechanisms which are involved in the pathophysiology of anemia associated with DN. Although the major cause of anemia in DN is considered to be an inappropriate response of the plasma EPO concentration to anemia, several other possible mechanisms have been suggested. Glomerular hyperfiltration, proteinuria, renal tubular dysfunction and interstitial fibrosis are among the main culprits. On the other hand, systemic effects such as chronic inflammation, autonomic neuropathy and the renin-angiotensin system are also involved. Finally, several medications are considered to aggravate anemia associated with DN. Since anemia is an important predictor of quality of life and is implicated in the increased burden of cardiovascular morbidity and mortality, further research is required to elucidate its pathogenesis in diabetic patients.

Hepcidin-25 in diabetic chronic kidney disease is predictive for mortality and progression to end stage renal disease

Background

Anemia is common and is associated with impaired clinical outcomes in diabetic chronic kidney disease (CKD). It may be explained by reduced erythropoietin (EPO) synthesis, but recent data suggest that EPO-resistance and diminished iron availability due to inflammation contribute significantly. In this cohort study, we evaluated the impact of hepcidin-25—the key hormone of iron-metabolism—on clinical outcomes in diabetic patients with CKD along with endogenous EPO levels.

Methods

249 diabetic patients with CKD of any stage, excluding end-stage renal disease (ESRD), were enrolled (2003–2005), if they were not on EPO-stimulating agent and iron therapy. Hepcidin-25 levels were measured by radioimmunoassay. The association of hepcidin-25 at baseline with clinical variables was investigated using linear regression models. All-cause mortality and a composite endpoint of CKD progression (ESRD or doubling of serum creatinine) were analyzed by Cox proportional hazards models.

Results

Patients (age 67 yrs, 53% male, GFR 51 ml/min, hemoglobin 131 g/L, EPO 13.5 U/L, hepcidin-25 62.0 ng/ml) were followed for a median time of 4.2 yrs. Forty-nine patients died (19.7%) and forty (16.1%) patients reached the composite endpoint. Elevated hepcidin levels were independently associated with higher ferritin-levels, lower EPO-levels and impaired kidney function (all p<0.05). Hepcidin was related to mortality, along with its interaction with EPO, older age, greater proteinuria and elevated CRP (all p<0.05). Hepcidin was also predictive for progression of CKD, aside from baseline GFR, proteinuria, low albumin- and hemoglobin-levels and a history of CVD (all p<0.05).

Conclusions

We found hepcidin-25 to be associated with EPO and impaired kidney function in diabetic CKD. Elevated hepcidin-25 and EPO-levels were independent predictors of mortality, while hepcidin-25 was also predictive for progression of CKD. Both hepcidin-25 and EPO may represent important prognostic factors of clinical outcome and have the potential to further define “high risk” populations in CKD.

Genetic disposition and modifiable factors independently associated with anemia in patients with type 2 diabetes mellitus

AIMS

Anemia is prevalent but under-recognized in patients with diabetes mellitus (DM). Genetic variants in angiotensin-converting enzyme (ACE), tumor necrosis factor-alpha (TNF-α) and erythropoietin (EPO) have been associated with diabetic nephropathy. In the present study, we investigated the associations between anemia and polymorphisms in EPO promoter (rs1617640), TNF-α G-308A and ACE Insertion/Deletion in Chinese patients with type 2 diabetes.

METHODS

Polymorphisms in ACE, TNF-α and EPO were genotyped in 1142 patients. Anemia was defined as hemoglobin (Hb) levels below 12 g/dL for women and 13 g/dL for men.

RESULTS

286 (25%) patients had anemia. Patients with anemia were older, had longer duration of diabetes, worse renal function and more albuminuria. ACE Insertion/Deletion and TNF-a G-308A were not associated with anemia. The frequencies of EPO polymorphism (rs1617640) were significantly different between anemic and nonanemic patients. Patients with TT genotype had higher prevalence of anemia than those with TG and GG. Regression analysis identified EPO SNP, duration of DM, serum albumin, albuminuria and renal function independently associated with anemia. After adjusting for multiple variables, TT and TG genotypes were associated with 3-5-fold increased risk for anemia compared to GG.

CONCLUSIONS

The EPO genotype in Chinese patients with type 2 diabetes is associated with anemia and may help to identify those at risk. Further evaluation of its effect on clinical outcomes in prospective studies may be useful to predict the outcomes of erythropoiesis stimulating therapy, and to individualize anemia management.

Diabetes mellitus with normal renal function is associated with anaemia

BACKGROUND

Anaemia is a common complication of diabetes mellitus (DM), usually related to renal failure. There is scarce information as to the levels of haemoglobin (Hb) and the rate of anaemia in diabetic patients with normal renal function. We, therefore, evaluated haemoglobin levels and the rate of anaemia in diabetic subjects with normal renal functions [estimated glomerular filtration rate (eGFR) > 60 mL/min].

METHODS

The charts of 9250 subjects who attended the Institute of Periodic Medical Examinations at the Chaim Sheba Medical Center for a routine yearly check-up were reviewed. Four hundred and forty-five subjects with type 2 DM and normal renal function were indentified and compared with those without DM who were routinely examined at the same time. Subjects' electronic records were used to build a biochemical and clinical database.

RESULTS

Mean haemoglobin levels were lower in subjects with DM than in those without (14.2 vs. 14.7 g/dL, respectively; p < 0.001). Anaemia was observed in 48 (10.8%) subjects in the diabetic group and in only 12 (2.7%) in the nondiabetic group (p < 0.001). Multivariate analysis revealed that age, gender, history of gastrointestinal disease, use of beta blockers, renal function and DM were independent determinants of haemoglobin levels. After adjustment for age, gender, history of gastrointestinal tract diseases and renal function, DM remained a significant determinant of anaemia with an odds ratio of 2.15 (confidence interval: 1.07-4.31).

CONCLUSIONS

Anaemia is more common in diabetic patients even when eGFR > 60 mL/min.

Early colonoscopy confers survival benefits on colon cancer patients with pre-existing iron deficiency anemia: a nationwide population-based study

This study aimed to examine the prognostic significance of pre-existing iron deficiency anemia (IDA) and the benefits of early colonoscopy in patients with colon cancer, since these have not been clearly established to date. Using the Taiwanese National Health Insurance Research Database, we retrieved and retrospectively reviewed the records of patients aged ≥55 years who were diagnosed with colon cancer between 2000 and 2005. The patient cohort was divided into two groups: patients with (n = 1,260) or without (n = 15,912) an IDA diagnosis during ≤18 months preceding the date of colon cancer diagnosis. We found that diabetes (27.9% vs. 20.3%, p<0.0001), cardiovascular disease (61.6% vs. 54.7%, p<0.001), and chronic kidney disease (4.6% vs. 2.2%, p<0.0001) were more common among patients with IDA than among those without IDA. The median overall survival times for patients with IDA and those without IDA were 4.6 and 5.7 years, respectively (p = 0.002). Patients who underwent colonoscopy ≤30 days, 31–90, and ≥91 days after IDA diagnosis showed median overall survival times of 5.79, 4.43, and 4.04 years, respectively (p = 0.003). Delayed colonoscopy was an independent factor associated with poor overall survival (adjusted hazard ratio, 1.28; 95% confidence interval, 1.07–1.53; p = 0.01). In conclusion, colon cancer patients with IDA were more likely to experience comorbidities than were those without IDA. Pre-existing IDA was a poor prognostic factor in adult men and postmenopausal women who had colon cancer. Early colonoscopy could improve overall survival possibly by facilitating early diagnosis and treatment.

Deferiprone: structural and functional modulating agent of hemoglobin fructation

Diabetic complication arises from the presence of advanced glycation end products in different sites of the body. Great attention should be paid to recognizing anti-glycation compounds. Here, deferiprone as an oral iron chelator drug administrated in treatment of β-thalassemic patients was selected to find its effect on the fructation of hemoglobin (Hb). Our results indicated that deferiprone could prevent the AGE and carbonyl formation via inhibition of structural changes in the structure of Hb during the fructation process. Moreover, deferiprone can preserve peroxidase and esterase activities of fructated Hb similar to native Hb. Therefore, deferiprone can be introduced as an anti-glycation drug to prevent the AGE formation.

Impact of thyroid dysfunction on erythropoietin dosage in hemodialysis patients

BACKGROUND

Although thyroid diseases exist in patients with renal failure, thyroid function tests are not routine tests in patients on chronic hemodialysis (HD). Therefore, the impact of thyroid diseases on erythropoietin (EPO) dosage in HD patients is not well defined. This study evaluated the relationship between the dose of EPO and the presence or absence of thyroid dysfunction in HD patients.

METHODS

This study included 1013 adult patients on HD who did not have a malignancy, liver cirrhosis, thalassemia, iron deficiency, gastrointestinal bleeding, or a major operation within 6 months. Patients were characterized as being euthyroid, or having the sick euthyroid syndrome, primary hypothyroidism, subclinical hypothyroidism, hyperthyroidism, or subclinical hyperthyroidism based on thyroid function tests. Routine biochemistry profiles including an index of the efficiency of HD, along with clinical data over the previous 6-month period, were collected and analyzed. Multiple regression models were employed to assess the relationship between the dose of EPO and the presence or absence of thyroid status.

RESULTS

The mean monthly EPO dosages were 77.7±37.0, 70.2±40.6, 90.8±68.4, 78.5±46.7, and 82.3±41.2 μg, respectively, in the sick euthyroid syndrome, euthyroid patients, hypothyroidism, subclinical hypothyroidism, and subclinical hyperthyroidism groups (p<0.05). After adjustment of all other variables in multiple regression, the mean monthly EPO dosage was 19.00±8.59 μg more in hypothyroid patients compared with euthyroid patients (p=0.027). Further, considering an interaction with the presence of diabetes, the mean monthly EPO dosage in patients with either hypothyroidism or subclinical hypothyroidism and diabetes was 54.66±17.12 μg (p=0.001) and 31.51±10.38 μg more than that of euthyroid patients, respectively (p=0.002).

CONCLUSIONS

In HD patients, the EPO dosage required to maintain the target hemoglobin level is significantly higher in patients having both hypothyroidism or subclinical hypothyroidism and diabetes than in euthyroid patients.

Anaemia, diabetes and chronic kidney disease: where are we now?

Anaemia is a common finding in people with diabetes and chronic kidney disease and failure of the kidney to produce erythro-poietin in response to a falling haemoglobin concentration is a key component, correlating with the degree of albuminuria, renal dysfunction and iron deficiency. Anaemia in diabetes is associated with a number of adverse outcomes, including increased risk of all cause and cardiovascular mortality. Whether or not anaemia is a marker or mediator of adverse outcome still remains to be completely resolved. Treatment of anaemia in diabetes has quality of life benefits and reduces transfusion requirements. Correction of anaemia to normal haemoglobin concentrations is associated with significant adverse cardiovascular outcomes and is not recommended, escalating doses of erythropoiesis-stimulating agents should be avoided. The treatment of anaemia in people with diabetes and chronic kidney disease should begin with optimisation of iron stores. An aspirational haemoglobin concentration range of 10-12 g/dl with anaemia management, balances proven benefits of anaemia treatment with potential cardiovascular risk.

Increased caspase-3 immunoreactivity of erythrocytes in STZ diabetic rats

Eryptosis is a term to define apoptosis of erythrocytes. Oxidative stress and hyperglycemia, both of which exist in the diabetic intravascular environment, can trigger eryptosis of erythrocytes. In this experimental study, it is presented that the majority of erythrocytes shows caspase-3 immunoreactivity in streptozocin- (STZ)-induced diabetic rats. Besides that, caspase-3 positive erythrocytes are aggregated and attached to vascular endothelium. In conclusion, these results may start a debate that eryptosis could have a role in the diabetic complications.

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.

Prevalence of kidney disease in anaemia differs by GFR-estimating method: the Third National Health and Nutrition Examination Survey (1988-94)

BACKGROUND

Anaemia worsens as kidney function declines. Both conditions are associated with increased mortality. Serum cystatin C is purportedly a more sensitive marker of kidney disease and a better predictor of mortality than serum creatinine. However, studies suggest that extrarenal factors also influence cystatin C levels.

METHODS

We determined whether estimates of glomerular filtration rate [estimated glomerular filtration rate (eGFR)] based on serum cystatin C alone or in combination with serum creatinine were superior to those based on serum creatinine in recognizing impaired kidney function in the setting of anaemia in a sub-sample of the Third National Health and Nutrition Examination Survey of the USA consisting of 6734 participants, 20 years or older.

RESULTS

The prevalence of moderate to severe kidney disease (eGFR 15-59 mL/min/1.73 m(2)) among anaemic persons was 15-16% when based on serum creatinine alone (eGFR(SCR)) or combined with cystatin C (eGFR(SCR) (+) (CYSC)); this estimate increased to nearly 25% when kidney function was estimated by cystatin C (eGFR(CYSC)). The adjusted odds ratios of kidney disease in anaemic versus non-anaemic persons were slightly higher with eGFR(CYSC) than eGFR(SCR) and eGFR(SCR) (+) (CYSC) in younger adults [odds ratio (OR) = 5.22, 95% confidence interval (CI): 2.23, 12.17], women (OR = 5.34, 95% CI: 2.36, 12.06) and those with elevated C-reactive protein (CRP) (OR = 7.36, 95% CI: 1.98-27.36).

CONCLUSIONS

Impaired kidney function was common in individuals with anaemia. Among anaemic individuals, the prevalence estimate for kidney disease was notably higher when kidney function was estimated by cystatin C alone compared with the estimations by serum creatinine alone or in combination with serum cystatin C. eGFR(CYSC) may be particularly helpful in identifying kidney disease in the setting of anaemia among younger persons, women and those with elevated CRP. Regardless of which renal biomarker is used, our study suggests that an evaluation for underlying kidney disease should be considered in the standard workup of anaemia.

Hemoglobin concentration in men with type 2 diabetes mellitus

Anemia is a common but often overlooked complication of diabetes. We investigated the relationship between hemoglobin concentration and various factors as well as markers of subclinical atherosclerosis in men with type 2 diabetes mellitus. Hemoglobin concentration was measured in 319 men with type 2 diabetes mellitus. We evaluated the relationship between hemoglobin concentration and various factors including age, body mass index, and glycemic control, as well as between hemoglobin concentration and pulse wave velocity or ankle-brachial index (n = 209) and between hemoglobin concentration and carotid intima-media thickness or plaque score (n = 125). Mean hemoglobin concentration was 14.2 +/- 0.80 g/dL. Body mass index (r = 0.340, P < .0001) and estimated glomerular filtration rate (r = 0.219, P = .0011) were positively associated with hemoglobin concentration, whereas age (r = -0.388, P < .0001), glycated albumin (r = -0.148, P = .0121), serum creatinine concentration (r = -0.206, P = .0019), and log (urinary albumin excretion) (r = -0.188, P = .0010) were negatively associated with hemoglobin concentration. Multiple regression analysis identified age (beta = -0.222, P = .0019), body mass index (beta = 0.145, P = .0432), systolic blood pressure (beta = 0.214, P = .0015), total cholesterol concentration (beta = 0.170, P = .0077), and serum creatinine concentration (beta = -0.181, P = .0045) as independent determinants of hemoglobin concentration. No significant association was observed between hemoglobin concentration and serum erythropoietin concentration (r = -0.079, P = .2980). Negative correlations were found between hemoglobin concentration and pulse wave velocity (r = -0.289, P < .0001) and between hemoglobin concentration and plaque score (r = -0.275, P = .0024). In conclusion, hemoglobin concentration was associated with various factors; and decreased hemoglobin concentration was associated with subclinical markers of atherosclerosis in men with type 2 diabetes mellitus.

Anemia in diabetic patients at an internal medicine ward: clinical correlates and prognostic significance

BACKGROUND

Characteristics and prognostic significance of anemia in hospitalized diabetic patients are unknown.

METHODS

We studied 3145 unselected patients admitted to two Internal Medicine Departments, 872 (27.7%) of whom were diabetic. Forty diabetic patients died during the first hospitalization period. Out of the remaining 832 patients, 334 (40.2%) were anemic and evaluated for survival. In 87 diabetic patients, the cause of anemia was evident on admission, whereas the other 247 had to be further investigated for etiology of anemia.

RESULTS

Compared to non-anemic diabetic patients, the diabetic anemic patients were older (mean age 71.4 vs. 64.4 years, P<.001) and predominantly females (52.4% vs. 44.4%, P<.02). Of the 247 evaluated patients, 38% were deficient in iron, 12% in vitamin B(12) and/or folate, 54% had anemia of chronic disease, 47% suffered from heart failure, 39% had renal dysfunction and 22% were complex nursing care patients and/or had diabetic foot. On median follow-up of 19.2 months, mortality rate was higher in anemic compared to non-anemic diabetic patients (17.3% vs. 4%, P<.001), the main cause of death being infection. Male sex (P=.03), albuminuria (P=.01) and heart failure (P=.06) were associated with shorter survival, male sex being the most significant (OR 2.02, 95% CI 1.04-4.00).

CONCLUSION

Frequency of anemia was increased in diabetic patients admitted to the Internal Medicine Departments, compared to the studies performed on ambulatory patient populations. Anemia was multifactorial and associated with higher mortality, predominantly from infections. Males with albuminuria and heart failure were at higher risk of death.

Erythropoietic stress and anemia in diabetes mellitus

Anemia is one of the world's most common preventable conditions, yet it is often overlooked, especially in people with diabetes mellitus. Diabetes-related chronic hyperglycemia can lead to a hypoxic environment in the renal interstitium, which results in impaired production of erythropoietin by the peritubular fibroblasts and subsequent anemia. Anemia in patients with diabetes mellitus might contribute to the pathogenesis and progression of cardiovascular disease and aggravate diabetic nephropathy and retinopathy. Anemia occurs earlier in patients with diabetic renal disease than in nondiabetic individuals with chronic kidney disease. Although erythropoietin has been used to treat renal anemia for nearly two decades, debate persists over the optimal target hemoglobin level. Most guidelines recommend that hemoglobin levels be maintained between 105g/l and 125g/l. The suggested role of anemia correction--to prevent the progression of left ventricular hypertrophy in patients with diabetes mellitus--is yet to be established. However, an emphasis on regular screening for anemia, alongside that for other diabetes-related complications, might help to delay the progression of vascular complications in these patients.

Low testosterone and anaemia in men with type 2 diabetes

OBJECTIVE

Anaemia is frequently found in patients with diabetes, in whom it is associated with increased morbidity and mortality. Low testosterone levels are also common in men with type 2 diabetes. We hypothesized that low testosterone levels are also associated with anaemia in men with type 2 diabetes, over the effects of chronic kidney disease.

DESIGN

Cross-sectional cohort study, performed in 2005 in a tertiary diabetes clinic. Patients 464 men with type 2 diabetes.

MAIN OUTCOME MEASURE

Anaemia (haemoglobin (Hb) < 13.7 g/dl in men aged < 60, or < 13.2 g/dl in men aged 60 and older).

RESULTS

About 24% of study participants had anaemia, which was associated with the presence and severity of chronic kidney disease, systemic inflammation, increased age, and reduced iron availability. In addition, testosterone levels were independently associated with reduced Hb levels, determining between 6 and 8% of the total variability in raw Hb levels in this population after adjusting for these other factors. Individuals with total testosterone level < 10 nmol/l (43% of the cohort) were more likely to have anaemia (adjusted odds ratio 1.7; 95% CI 1.1-2.8). Similarly, anaemia was twice as common in individuals with a calculated free testosterone of < 0.23 nmol/l (adjusted odds ratio 2.0, 95% CI 1.2-3.1).

CONCLUSIONS

These findings suggest that testosterone deficiency may contribute to the increased frequency of anaemia in men with type 2 diabetes. However, the appropriate clinical response to testosterone deficiency in anaemic patients remains to be established by prospective clinical trials.

Body iron stores in relation to the metabolic syndrome, glycemic control and complications in female patients with type 2 diabetes

BACKGROUND AND AIM

Studies suggest that iron plays a significant role in the development of diabetes and its complications. This study evaluates the associations of iron metabolism parameters with the metabolic syndrome (MS), control and complications in female patients with type 2 diabetes mellitus (T2DM).

METHODS AND RESULTS

Ferritin, soluble Transferrin Receptor (sTfR), sTfR/Log ferritin ratio (sTfR-F index), iron, full blood count and high-sensitivity C-reactive protein (hs-CRP) were determined in 110 female patients with T2DM. Steady state beta cell function (%B), insulin sensitivity (%S) and insulin resistance were assessed with homeostasis model. Patients were divided into tertiles of ferritin and sTfR-F index and according to the presence or absence of the MS and diabetic complications. Patients within the lowest tertile of the sTfR-F index had significantly higher fasting insulin, percent B, low-density lipoprotein cholesterol and Apolipoprotein B than those in the highest tertile. Ferritin showed significant correlations with insulin, percent B and inverse correlations with adiponectin and percent S. The sTfR-F index was significantly correlated with insulin, percent B and lipid parameters. Correcting for hs-CRP abolished the correlations with ferritin but not the sTfR-F index. Higher indices of body iron were significantly associated with diabetes complications but no associations were found with MS, glucose or glycemic control. Multiple regression analysis with confounding variables showed ferritin and the sTfR-F index were not independently associated with diabetes complications.

CONCLUSIONS

Association of ferritin with metabolic derangements and complications in diabetes is partly dependent on association with inflammation. Iron status, estimated with the sTfR-F index, is associated with metabolic derangements and complications but the associations are dependent on other risk factors. Prospective studies that use the sTfR-F index as a marker of iron status are required to confirm the role of iron in the etiopathogenesis of T2DM and its complications.

Mechanisms of disease: the hypoxic tubular hypothesis of diabetic nephropathy

Diabetic nephropathy is traditionally considered to be a primarily glomerular disease, although this contention has recently been challenged. Early tubular injury has been reported in patients with diabetes mellitus whose glomerular function is intact. Chronic hypoxia of the tubulointerstitium has been recognized as a mechanism of progression that is common to many renal diseases. The hypoxic milieu in early-stage diabetic nephropathy is aggravated by manifestations of chronic hyperglycemia-abnormalities of red blood cells, oxidative stress, sympathetic denervation of the kidney due to autonomic neuropathy, and diabetes-mellitus-induced tubular apoptosis; as such, tubulointerstitial hypoxia in diabetes mellitus might be an important early event. Chronic hypoxia could have a dominant pathogenic role in diabetic nephropathy, not only in promoting progression but also during initiation of the condition. Early loss of tubular and peritubular cells reduces production of 1,25-dihydroxyvitamin D3 and erythropoietin, which, together with dysfunction of their receptors caused by the diabetic state, diminishes the local trophic effects of the hormones. This diminution could further compromise the functional and structural integrity of the parenchyma and contribute to the gradual decline of renal function.

Prognostic usefulness of anemia and N-terminal pro-brain natriuretic peptide in outpatients with systolic heart failure

N-terminal pro-brain natriuretic peptide (NT-pro-BNP) and anemia are predictors of outcome in systolic heart failure. It is currently unclear how these 2 markers interact in particular with regard to the prognostic information carried by each risk marker. We therefore tested the hypothesis that anemia (World Health Organization criteria, hemoglobin levels <7.5 mmol/L for women and <8.0 mmol/L for men) and NT-pro-BNP are associated and evaluated how a possible association affects the prognostic value of each risk marker. Clinical data from 345 patients with systolic heart failure were obtained prospectively at the baseline visit to our heart failure clinic (inclusion criterion left ventricular ejection fraction <0.45, no exclusion criteria). Follow-up was 30 months (median), and 70 events (mortality) occurred. Prevalence of anemia was 27%. In a multivariate logistic regression model, anemia (p = 0.041) was closely associated with NT-pro-BNP levels above the median (1,381 pg/ml) after adjustment for traditional confounders (left ventricular ejection fraction, age, body mass index, atrial fibrillation, chronic kidney disease). In an adjusted Cox proportional hazard model, the 2 parameters were associated with mortality after adjustment for traditional confounders (hazard ratio for anemia 1.73, 95% confidence interval 1.06 to 2.83, p = 0.029; hazard ratio for NT-pro-BNP >1,381 pg/ml 2.68, 95% confidence interval 1.58 to 4.66, p <0.001). Patients with anemia and high NT-pro-BNP levels had a fivefold increased risk for mortality (hazard ratio 4.77, 95% confidence interval 2.47 to 9.18, p <0.001). In conclusion, anemia is closely associated with NT-pro-BNP in patients with systolic heart failure, and anemia and NT-pro-BNP carry independent prognostic information. Patients with anemia and high levels of NT-pro-BNP have a markedly increased mortality risk.

Pathogenesis of renal anemia

Anemia is a common complication of chronic kidney disease. Although mechanisms involved in the pathogenesis of renal anemia include chronic inflammation, iron deficiency, and shortened half-life of erythrocytes, the primary cause is deficiency of erythropoietin (EPO). Serum EPO levels in patients with chronic kidney disease are usually within the normal range and thus fail to show an appropriate increase with decreasing hemoglobin levels, as found in nonrenal anemias. Studies elucidating the regulation of EPO expression led to the identification of the hypoxia inducible factor-hypoxia responsive element system. However, despite much progress in understanding the molecular mechanisms through which cells can sense oxygen availability and translate this information into altered gene expression, the reason why EPO production is inappropriately low in diseased kidneys remains incompletely understood. Both alterations in the function of EPO-producing cells and perturbations of the oxygen-sensing mechanism in the kidney may contribute. As with other anemias, the consequences of renal anemia are a moderate decrease in tissue oxygen tensions and counterregulatory mechanisms that maintain total oxygen consumption, including a persistent increase in cardiac output.

Anemia in patients with diabetes mellitus

Introduction: Anemia is more common and pronounced in patients with diabetic, than in patients with non-diabetic renal disease. While several factors contribute to its pathogenesis, the failure of the kidney to increase erythropoietin in response to falling hemoglobin appears to be the dominant factor. The most frequent complications of anemia in diabetic patients include decreased quality of life and work capacity and increased cardiovascular morbidity and mortality. Material and Methods: This cross-sectional multicenter study included a total of 539 patients with type I (~20%) and type II diabetes (~80%) classified into five stages according to the glomerular filtration rate. Results Diabetic nephropathy appears in stage I, and progresses in all patients to the stage V (p=0.045). The presence of anemia progressively increased from stage I to stage V (from 60% to 100%, p=0.008). Only 62% of patients with anemia were treated (mainly with iron) and only 3.4% received erythropoietin treatment. Hypertension was present in 90% of patients in stage I and in 100% of patients in stage V nephropathy. The presence of heart failure increased from 0% (stage I) to 51% (stage IV, p=0.03). Around 62% of patients were referred to a nephrologist, and according to the logistic regression model, renal failure and presence of anemia were significant predictors of patients' referral to nephrologist. Conclusion: In a primary care setting, anemia is a frequent finding, even in the very beginning of diabetic renal disease. Currently available guidelines for management of anemia are not followed; this may explain high percentage of patients with heart failure in pre-dialysis stage. Early referral to a nephrologist and regular follow-up by an endocrinologist and cardiologist are the best way for the prevention of diabetic complications and comorbidity.

Compensatory secondary structure alterations in protein glycation

Glycation, a local covalent interaction, leads to alterations in secondary and tertiary structures of hemoglobin, the changes produced by fructose being more pronounced than those caused by glucose. The Stokes diameter of hemoglobin increases upon glycation from 7 to 14 nm and a concurrent inter-chain cross-linking and heme loss are also observed, particularly in the later stage of glycation. An initial increase of tryptophan (trp) fluorescence was observed in both glucation and fructation. In case of frucation however there was a decrease in tryptophan fluorescence that was accompanied by an increase in fluorescence of the advanced glycosylation end products (AGEs). This fluorescence behavior is indicative of energy transfer between tryptophan and the AGEs formed during the late stage of glycation. Emergence of an isosbestic point in the fluorescence spectra (taken at different time intervals) implies existence of two distinct glycation stages. The late glycation stage is also marked by an increase of beta structure and random coil at the expense of alpha helix. It is further observed that this compensatory loss of alpha helix (reported for the first time) and increase in beta sheet and random coil elements depend on the number of solvent-accessible glycation sites (rather than total number of such sites) and the subunit assembly of the protein.

Prevalence and severity of anaemia in patients with type 2 diabetic nephropathy and different degrees of chronic renal insufficiency

BACKGROUND/AIM

Type 2 diabetes mellitus is the single most common cause of chronic kidney disease (CKD); however its real impact on renal anaemia has not been established. The aim of this study was to evaluate whether onset, severity, and prevalence of anaemia during the course of CKD is different between type 2 diabetic and non-diabetic patients.

METHODS

We enrolled 281 patients with: (1) type 2 diabetes and no CKD (n = 75); (2) type 2 diabetes plus CKD (n = 106), and (3) CKD without type 2 diabetes (n = 100). According to K/DOQI guidelines, the patients with renal insufficiency (i.e., those with a glomerular filtration rate <60 ml/min) were subgrouped into three tertiles of CKD: (1) stage 3 (creatinine clearance 60-30 ml/min); (2) stage 4 (creatinine clearance 29-15 ml/min), and (3) stage 5 (creatinine clearance <15 ml/min).

RESULTS

Anaemia was observed in 16% of the diabetic patients without CKD; it was more frequent in the diabetic patients with CKD than in the non-diabetic patients with CKD (61.7 vs. 52%, p < 0.05). The comparison among the tertiles showed that the prevalence of anaemia was significantly higher only in diabetic CKD patients of stages 4 and 5. The prevalence was higher in females independently of type 2 diabetes mellitus. In diabetics with a normal renal function, the haemoglobin levels were higher than in diabetics and non-diabetics with CKD, but the diabetics showed lower levels of haemoglobin than non-diabetics at stage 3 and stage 4 of CKD.

CONCLUSIONS

Diabetic patients with CKD of stages 4 and 5 have a higher prevalence of anaemia than non-diabetic patients with comparable glomerular filtration rate. A higher awareness of this risk will allow earlier diagnosis and treatment.