Association of anemia with outcomes in men with moderate and severe chronic kidney disease

Iron therapy in chronic kidney disease: current controversies

Anaemia in chronic kidney disease (CKD) is a complex disease that requires an integrated approach to incorporate both diagnostic and therapeutic interventions and to address the different facets of its aetiology and pathophysiology. The advent of erythropoiesis stimulating agents (ESA) has revolutionised the therapy of anaemia of CKD, and has resulted in a significant decline in the need for blood transfusions in CKD patients. The routine application of ESA has also led to the need for concomitant iron supplementation. ESA and iron therapy now form the cornerstone of anaemia management in CKD. Intravenous iron administration is effective with acceptable safety, and may improve ESA responsiveness. However, less is known about the long-term safety of iron supplementation in CKD patients. Whereas maintenance (weekly to monthly) intravenous iron has been routinely used in maintenance dialysis patients, iron replacement in patients with non-dialysis-dependent CKD is less well studied, in spite of the much larger number of patients affected. This review discusses iron supplementation in CKD with an emphasis toward controversial issues that continue to pose dilemmas in clinical practice. Concerns related to both the optimal amount of iron supplementation and to the safety of various agents available in clinical practice are presented.

Iron supplementation in the non-dialysis chronic kidney disease (ND-CKD) patient: oral or intravenous?

BACKGROUND

The management of iron-deficiency anaemia in patients with non-dialysis chronic kidney disease (ND-CKD) remains controversial, particularly regarding the use of oral versus intravenous iron supplementation.

METHODS

A PubMed search from 1970 to February 2009 was conducted to identify relevant research articles.

FINDINGS

Iron supplementation is advisable for all iron-deficient CKD patients receiving erythropoiesis stimulating agents (ESAs), and intravenous iron may be preferable to oral iron. However, there is also a growing body of data indicating that iron supplementation may avoid or delay the need for ESA therapy in some ND-CKD patients. In each of four randomised trials that included ND-CKD patients without ESA, the haemoglobin response was greater with i.v. versus oral iron. Moreover, some ND-CKD patients who remain anaemic on oral iron may subsequently respond to i.v. iron. Newer preparations (ferric carboxymaltose and ferumoxytol) permit rapid, high-dose administration. In a randomised study, a single 15-minute injection of ferric carboxymaltose, with up to two additional doses as required, resulted in 53.2% of ND-CKD patients achieving > or =1 g/dL increase in haemoglobin by day 56 without ESA, compared to 29.9% of patients given oral iron supplements. Two large, randomised, ongoing trials will address the important question of whether i.v. or oral iron supplementation affects the progression of renal dysfunction. While i.v. iron is more costly than oral iron, the cost differential over time may be lower than widely believed, and i.v. therapy avoids the poor absorption, gastrointestinal intolerance and non-compliance associated with oral preparations. In terms of safety, true anaphylaxis does not occur with modern preparations such as iron sucrose and iron gluconate. The novel preparations ferric carboxymaltose and ferumoxytol do not require a test dose and appear to offer a good safety profile, but long-term safety monitoring is mandatory.

CONCLUSIONS

Intravenous iron offers an effective, feasible route towards reducing the heavy burden of iron-deficiency anaemia in the non-dialysis CKD patient, even in the absence of ESA therapy.

Clinical presentation of renal failure in the aged: chronic renal failure

Chronic kidney disease is increasingly being recognized in elderly individuals across the world. An understanding of the methods used to estimate or to measure kidney function, the likelihood and factors associated with progressive decline in renal function, and the clinical syndromes associated with poor renal function are key topics for individuals working across many medical disciplines. This review addresses some of the important aspects of chronic kidney disease, and summarizes some of the clinical and laboratory features associated with progressive disease.

Outcomes associated with serum calcium level in men with non-dialysis-dependent chronic kidney disease

BACKGROUND AND OBJECTIVES

Elevated serum calcium has been associated with increased mortality in dialysis patients, but it is unclear whether the same is true in non-dialysis-dependent (NDD) chronic kidney disease (CKD). Outcomes associated with low serum calcium are also not well-characterized.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined associations of baseline, time-varying, and time-averaged serum calcium with all-cause mortality in a historic prospective cohort of 1243 men with moderate and advanced NDD CKD by using Cox models.

RESULTS

The association of serum calcium with mortality varied according to the applied statistical models. Higher baseline calcium and time-averaged calcium were associated with higher mortality (multivariable adjusted hazard ratio (95% confidence interval): 1.31 (1.13, 1.53); P < 0.001 for a baseline calcium 1 mg/dl higher). However, in time-varying analyses, lower calcium levels were associated with increased mortality.

CONCLUSIONS

Higher serum calcium is associated with increased long-term mortality (as reflected by the baseline and time-averaged models), and lower serum calcium is associated with increased short-term mortality (as reflected by the time-varying models) in patients with NDD CKD. Clinical trials are warranted to determine whether maintaining normal serum calcium can improve outcomes in these patients.

[Anemia in chronic kidney disease and its cardiovascular implications]

Cardiovascular disease is the leading cause of death in patients with chronic kidney disease (CKD). Anemia is a common complication of CKD and it is an important independent risk factor for the development and progression of left ventricular hypertrophy (LVH) and heart failure. Anemia is also independently and synergistically associated with an enhanced risk of cardiovascular morbidity and mortality in CKD patients. The availability of erythropoiesis stimulating agents (ESA), such as recombinant human erythropoietin, has greatly improved the management of anemia in CKD patients. By increasing hemoglobin levels, ESA therapy has demonstrated to significantly improve quality of life and decrease morbidity and mortality among these patients. Earlier studies suggested that partial correction of anemia in CKD patients with LVH induced a partial regression of LV mass, while mainly uncontrolled and small-sized studies have suggested that anemia treatment with ESA in CKD patients with congestive heart failure improved NYHA class, cardiac function and reduced hospitalization rates. On the other hand, recent randomized controlled trials have reported no benefit of full anemia correction on LVH and no benefit, or even worse outcomes, in CKD patients versus partial anemia correction. Thus, recent anemia guidelines recommend target haemoglobin levels between 11-12 g/dl in CKD patients receiving ESA.

CMV seropositivity determines epoetin dose and hemoglobin levels in patients with CKD

Cytomegalovirus (CMV)-seropositive patients with ESRD may have more CD4(+) T cells lacking the co-stimulatory molecule CD28 (CD4(+)CD28null) than CMV-seronegative patients. Increased numbers of CD28null T cells associates with epoetin nonresponsiveness in patients with ESRD, but whether expansion of CD4+CD28null T cells in CMV-seropositive patients associates with demand for epoetin is unknown. In a cohort of 129 stable patients with ESRD, CMV seropositivity significantly associated with a lower hemoglobin level in predialysis patients (12.5 versus 11.5 g/dl; P < 0.02). CMV seropositivity did not associate with average hemoglobin level in hemodialysis patients, but CMV-seropositive patients required significantly more epoetin (median 12,000 versus 6300 U/wk; P = 0.02). Multivariate linear regression analysis identified CMV seropositivity as the only variable significantly associated with hemoglobin levels in predialysis patients and epoetin dosages in hemodialysis patients. In CMV-seropositive hemodialysis patients, the number of circulating CD4(+)CD28null T cells positively correlated with epoetin dosage. These CD4(+)CD28null T cells were proinflammatory; they were capable of producing large amounts of IFN-gamma and TNF-alpha. In conclusion, expansion of CD4(+)CD28null T cells in CMV-seropositive patients with ESRD associates with increased demand for epoetin.

Similar renal decline in diabetic and non-diabetic patients with comparable levels of albuminuria

BACKGROUND

Diabetes is the main cause of ESRD, and albuminuria is a major determinant of adverse renal outcome. Likewise, albuminuria is an intermediate risk factor of chronic kidney disease (CKD) progression in diabetic patients. Our aim was to compare the rate of renal decline in diabetic and non-diabetic CKD patients (GFR < 50 ml/min) with comparable levels of albuminuria.

METHODS

In this observational study, 333 patients (age 67 +/- 15 years, 46% diabetics) were included during a 7.5-year period. The mean follow-up was 30 +/- 18 months (range 4-79). The influence of study variables was evaluated applying a time-dependent Cox model and slope-based outcome using a linear regression model.

RESULTS

The diabetes condition was associated with adverse outcome in univariate analysis, and after adjusting for age, sex and systolic blood pressure. However, when controlling for albuminuria (a time-dependent covariate), diabetes did not show any association with outcome. In addition, the mean slope of renal decline was similar in diabetic and non-diabetic patients when controlling for albuminuria. The urinary albumin-creatinine ratio was a robust predictor of poor outcome in uni- and multivariate models. In the diabetic group, time-varying glycosilated haemoglobin did not influence renal outcome in the Cox model, and time-varying albuminuria remained a strong predictor of outcome.

CONCLUSIONS

Diabetic patients have a poorer renal outcome, but at comparable levels of albuminuria renal decline is similar in diabetic and non-diabetic patients. Albuminuria is a risk factor for renal decline, and the main target to delay progression in patients, diabetics or non-diabetics, with moderate to advanced CKD.

Exploration of anaemia as a progression factor in African Americans with cardiovascular disease

BACKGROUND

Despite the higher incidence of end-stage renal disease (ESRD) among African Americans, whites in the USA have a higher prevalence of chronic kidney disease. This may be due, in part, to faster progression to ESRD among African Americans. Anaemia is associated with a risk of kidney disease progression and is more prevalent among African Americans. The purpose of this study is to determine if anaemia is associated with progression to ESRD differently according to race.

METHODS

A retrospective cohort study of Cooperative Cardiovascular Project data for 87 693 Medicare beneficiaries >or=65 years old and ESRD free admitted to 4047 hospitals with acute myocardial infarction between February 1994 and June 1995 was conducted. Follow-up was collected through June 2004 for ESRD and mortality.

RESULTS

Among 87 693 patients, 7.0% were African Americans and 50.1% females. African Americans had a higher prevalence of anaemia than whites (40.2% versus 26.7%, respectively; P < 0.001). Lower haematocrit was associated with higher ESRD rates after adjustment, and the association of haematocrit with ESRD did not vary according to race (P = 0.19). This association was strongest at the lowest baseline kidney function (GFR <15) with hazard ratios increasing 7-fold as haematocrit decreased from >or= 42% to <28%.

CONCLUSIONS

In a nationally representative sample of patients with cardiovascular disease, anaemia was associated equally among African Americans and whites with an increased risk of ESRD.

Treatment of anemia among women with chronic kidney disease in United States outpatient settings

AIMS

Women with chronic kidney disease (CKD) are often at risk for anemia. This study examined variations in anemia care and management among women with CKD in outpatient settings in the United States.

METHODS

The study utilized National Ambulatory Medical Care Survey (NAMCS) data from 1996 to 2003. Women aged 18 years or older with CKD were included based on ICD-9-CM codes for CKD, anemia, and reason for visit. Anemia-related medications were retrieved using NAMCS drug codes.

RESULTS

Approximately 58 million weighted outpatient visits for women with CKD were made. Nearly 14% of these visits were by Hispanic women and 50% visits were by patients aged 65 years or older. Nephrologists accounted for only 15% of CKD patient visits and 51% of these patients had anemia diagnosis. Additionally, 32% of patients were using 5 or more medications. Women with Medicare coverage were 2.6 times more likely (p < .05) to be diagnosed with anemia by a nephrologist and were 2.4 times more likely (p < .05) to receive a prescription to treat anemia than patients seen by non-nephrologists. Hispanic women were 56% less likely (p < or = .05) to use 5 or more medications than non-Hispanic patients. CKD patients with anemia diagnosis were 50% less likely to receive 5 or more medications (p < or = .05).

CONCLUSION

This study found many risk factors associated with the diagnosis and treatment of anemia in women with CKD being treated in U.S. outpatient settings. Increased awareness of early treatments for anemia and assessments of patients receiving multiple medications is needed in women with CKD.

Posttransplant anemia: the role of sirolimus

Posttransplant anemia is a common problem that may hinder patients' quality of life. It occurs in 12 to 76% of patients, and is most common in the immediate posttransplant period. A variety of factors have been identified that increase the risk of posttransplant anemia, of which the level of renal function is most important. Sirolimus, a mammalian target of rapamycin inhibitor, has been implicated as playing a special role in posttransplant anemia. This review considers anemia associated with sirolimus, including its presentation, mechanisms, and management.

Review article: Biomarkers of clinical outcomes in advanced chronic kidney disease

Chronic kidney disease (CKD) is a complex condition, where the decrease in kidney function is accompanied by numerous metabolic changes affecting virtually all the organ systems of the human body. Many of the biomarkers characteristic of the individually affected organ systems have been associated with adverse outcomes including higher mortality in advanced CKD, whereas in persons without CKD these biomarkers may have no bearing on survival. It is believed that the high mortality seen in CKD is a result of several abnormalities conspiring to induce or aggravate a heightened degree of cardiovascular morbidity and predisposition to wasting syndrome. Not all the biomarkers may, however, be causally responsible for the adverse outcomes associated with them. We review various biomarkers of protein-energy wasting, inflammation, oxidative stress, potassium disarrays, acid-base disorders, bone and mineral disorders, glycemic status, and anemia. Although all of these biomarkers have shown associations with worsened outcomes in CKD, markers of protein-energy wasting, especially serum albumin, remain the strongest predictor of survival in CKD patients, especially those undergoing maintenance dialysis treatment. We also review the putative pathophysiologic mechanisms behind these associations, and present potential therapeutic interventions that could result in remedies to improve poor clinical outcomes in CKD, pending the results of current and future controlled trials.

Epoetin therapy and hemoglobin level variability in nondialysis patients with chronic kidney disease

BACKGROUND AND OBJECTIVES

Intrapatient variability of hemoglobin (Hb) is a newly proposed determinant of adverse outcome in chronic kidney disease (CKD). We evaluated whether intensity of epoetin therapy affects Hb variability and renal survival in nondialysis CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We calculated the individual therapeutic index (TI) for epoetin (EPO; difference between rates of visits that required EPO dosage change and those with effective EPO change) from 1198 visits during the first year of EPO in 137 patients. Renal death was registered in the subsequent 18.1 mo. Analysis was made by TI tertile (lower, middle, and higher; i.e., from more to less intensive therapy).

RESULTS

Main features and visit number were similar in tertiles. Lower Hb response to first EPO dosage was an independent predictor of higher TI (P = 0.002). The area under the curve for Hb (11.56 +/- 0.87, 11.46 +/- 1.20, and 10.95 +/- 1.48 g/dl per yr; P = 0.040) decreased from lower to higher tertile. Hb variability increased in parallel, as shown by the reduction of time with Hb at target (time in target, from 9.2 +/- 2.0 to 3.0 +/- 2.2 mo; P < 0.0001) and the wider values of within-patient Hb standard deviation (from 0.70 to 0.96; P = 0.005) and Hb fluctuations across target (P < 0.0001). In Cox analyses (hazard ratio [95% confidence interval]), risk for renal death was increased in the middle and higher tertiles (2.79 [1.36 to 5.73] and 2.94 [1.40 to 6.20]) and reduced by longer time in target (0.90 [0.83 to 0.98]).

CONCLUSIONS

Lack of adjustment of EPO worsens Hb variability in CKD. Hb variability may be associated with renal survival, but further studies are needed to explore the association versus causal relationship.

Hemoglobin variability in anemia of chronic kidney disease

Hemoglobin levels in individuals with chronic kidney disease fluctuate frequently above or below the recommended target levels within short periods of time even though the calculated mean hemoglobin remains within the target range of 11 to 12 g/dl. Both pharmacologic features and dosing of erythropoiesis-stimulating agents may lead to cyclic pattern of hemoglobin levels within the recommended range. Several longitudinal studies highlight the complexity of maintaining stable hemoglobin levels over time. As a consequence, patients may risk increased hospitalization and mortality, because both low and high hemoglobin levels are associated with increased cardiovascular events and death. The duration of time that hemoglobin remains higher or lower than the target thresholds may be important to adverse outcomes. It is not clear whether adverse effects of hemoglobin variability are because of the therapy with erythropoiesis-stimulating agents and/or iron or despite such a therapy. Several factors affect hemoglobin variability, including those that are drug related, such as pharmacokinetic parameters, patient-related differences in demographic characteristics, and factors affecting clinical status, as well as clinical practice guidelines, treatment protocols, and reimbursement policies. Strategies that consider each of these factors and reduce hemoglobin variability may be associated with improved clinical outcomes.

Anemia and cardiovascular risk in the patient with kidney disease

Patients with chronic kidney disease (CKD) often experience anemia, which causes fatigue and diminished quality of life. In addition, anemia in CKD has been associated with increased risk for cardiovascular events and left ventricular hypertrophy. To the extent that anemia plays a causal role in these relationships, treatment with erythropoiesis-stimulating agents (ESAs) could potentially help improve outcomes. To date, however, results from interventional studies have been disappointing in this regard. This article reviews the relationship between anemia in CKD and cardiovascular risk and explores current knowledge on ESA treatment.

Associates of mortality and hospitalization in hemodialysis: potentially actionable laboratory variables and vascular access

BACKGROUND

To determine the most significant potentially actionable clinical variables associated with mortality and hospitalization risk in hemodialysis (HD) patients.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

Adult maintenance HD patients in the Fresenius Medical Care, North America database as of January 1, 2004, with baseline information from October 1, 2003, to December 31, 2003, comprising approximately 26% of the US HD population.

PREDICTORS

Case-mix (age, sex, race, diabetes, vintage, and body surface area), vascular access, and laboratory (albumin, equilibrated Kt/V, hemoglobin, calcium, phosphorus, creatinine, bicarbonate, biointact parathyroid hormone, transferrin saturation, and white blood cell count) variables.

OUTCOMES

1-year mortality and hospitalization risk from January 1 to December 31, 2004.

MEASUREMENTS

Cox proportional hazards models for death and hospitalization.

RESULTS

The cohort (N = 78,420) had a mean age of 61.4 +/- 15.0 years, 47% were women, 49% were white, 41% were black race (10% defined as "other"), and 52% had diabetes. The top 5 actionable variables were the same for mortality and hospitalization. Final case-mix plus laboratory-adjusted hazard ratios for these top 5 actionable variables indicate 177% increased risk of death and 67% increased risk of hospitalization per 1-g/dL decrease in albumin level, 39% and 45% greater risk with catheters compared with fistulas, 18% and 9% greater risk per 1-mg/dL greater phosphorus level, 11% and 9% lower risk per 1-g/dL greater hemoglobin level, and 5% and 2% greater risk per 0.1-unit decrease in equilibrated Kt/V, respectively (all P < 0.0001).

LIMITATIONS

Observational cross-sectional study with limited comorbidity adjustment (for diabetes).

CONCLUSION

The same variables are associated with both mortality and hospitalization in HD patients. The top 5 potentially actionable variables are readily identifiable, with albumin level and catheter use the most prominent, and all 5 are appropriate targets for improvement.

Erythropoietin, iron depletion, and relative thrombocytosis: a possible explanation for hemoglobin-survival paradox in hemodialysis

BACKGROUND

High doses of human recombinant erythropoietin (rHuEPO) to achieve hemoglobin levels greater than 13 g/dL in patients with chronic kidney disease appear to be associated with increased mortality.

STUDY DESIGN

We conducted logistic regression and survival analyses in a retrospective cohort of long-term hemodialysis patients to examine the hypothesis that the induced iron depletion with resultant relative thrombocytosis may be a possible contributor to the link between the high rHuEPO dose-associated hemoglobin level of 13 g/dL or greater and mortality.

SETTING & PARTICIPANTS

The national database of a large dialysis organization (DaVita) with 40,787 long-term hemodialysis patients during July to December 2001 and their survival up to July 2004 were examined.

PREDICTORS

Hemoglobin level, platelet count, and administered rHuEPO dose during each calendar quarter.

OUTCOMES & OTHER MEASUREMENTS

Case-mix-adjusted 3-year all-cause mortality and measures of iron stores, including serum ferritin and iron saturation ratio.

RESULTS

Higher platelet count was associated with lower iron stores and greater prescribed rHuEPO dose. Compared with a hemoglobin level of 12 to 13 g/dL, a hemoglobin level of 13 g/dL or greater was associated with increased mortality in the presence of relative thrombocytosis, ie, platelet count of 300,000/microL or greater (case-mix-adjusted death-rate ratio, 1.21; 95% confidence limits, 1.02 to 1.44; P = 0.03) as opposed to the absence of relative thrombocytosis (death-rate ratio, 1.04; 95% confidence limits, 0.98 to 1.08; P = 0.1). A prescribed rHuEPO dose greater than 20,000 U/wk was associated with a greater likelihood of iron depletion (iron saturation ratio < 20%) and relative thrombocytosis (case-mix-adjusted odds ratio, 2.53; 95% confidence limits, 2.37 to 2.69; and 1.36; 95% confidence limits, 1.30 to 1.42, respectively; P < 0.001) and increased mortality during 3 years (death-rate ratio, 1.59; 95% confidence limits, 1.54 to 1.65; P < 0.001).

LIMITATIONS

Our results may incorporate uncontrolled confounding. Achieved hemoglobin level may have different mortality predictability than targeted hemoglobin level.

CONCLUSIONS

Iron depletion and associated relative thrombocytosis might contribute to increased mortality when administering high rHuEPO doses to achieve hemoglobin levels of 13 g/dL or greater in long-term hemodialysis patients. Randomized trials are needed to test these observational associations.

Anaemia in diabetic renal failure: is there a role for early erythropoietin treatment in preventing cardiovascular mortality?

The mortality rate in diabetics with chronic kidney disease (CKD) is seven times higher than end-stage renal disease mainly because of cardiac causes. Anaemia may have a relevant role in the pathogenesis of cardiovascular (CV) disease in CKD. Anaemia occurs at an earlier stage of CKD in diabetic individuals than in those with other causes of CKD. Observational findings support the unfavourable influence of anaemia on mortality in CKD patients, and the combination of anaemia and CKD in diabetics identifies a group with a particularly high mortality risk. While the effect of erythropoietin on these patients' quality of life is known, its impact on mortality and CV risk is uncertain. The recent Anaemia Correction in Diabetes (ACORD) trial in diabetic CKD patients, which targeted haemoglobin levels of 13-15 mg/dl, disclosed no statistically significant favourable or adverse effects on mortality or morbidity over the 2-year follow-up, while other studies endeavouring to nearly normalize haemoglobin have reportedly proved risky. Even if anaemia is causally involved, the pathogenesis of CV disease in diabetics with CKD is so complex that addressing just one factor (anaemia) may not suffice to prevent CV risk, and normalizing haemoglobin levels may even be harmful.

The role of anemia management in improving outcomes for African-Americans with chronic kidney disease

Chronic kidney disease (CKD) is a serious threat to African-American public health. In this population CKD progresses to end-stage renal disease (ESRD) at quadruple the rate in Caucasians. Factors fueling progression to ESRD include diabetes and hypertension, which show high prevalences and accelerated renal damage in African- Americans, as well as possible nutritional, socioeconomic, and genetic factors. Anemia, a common and deleterious complication of CKD, is more prevalent and severe in African-American than Caucasian patients at each stage of the disease. Proactive management of diabetes, hypertension, anemia, and other complications throughout the course of CKD can prevent or delay disease progression and alleviate the burden of ESRD for the African-American community. Currently, African-Americans with CKD are less likely than Caucasian patients to receive anemia treatment before and after the onset of dialysis. Although African-Americans often require higher doses of erythropoiesis-stimulating agents, this may result from late treatment initiation, lower hemoglobin levels, or the presence of comorbidities such as diabetes and inflammation, although racial differences in response cannot be excluded. This review explores racial-specific challenges and potential solutions in renal anemia management to improve outcomes in African-American patients.

Predicting renal replacement therapy and mortality in CKD

BACKGROUND

Prognostic risk scores can help clinicians intervene on higher risk patients and counsel them. Our objective is to identify characteristics that predict the rate of progression to renal replacement therapy (RRT) and evaluate how those characteristics predict mortality and a composite end point (RRT and mortality).

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

We conducted the study at Kaiser Permanente Northwest, a health maintenance organization. We followed up members with an estimated glomerular filtration rate (eGFR) that indicated chronic kidney disease (2 eGFRs < 60 mL/min/1.73 m(2) [<1.0 mL/s/1.73 m(2)] at least 90 days apart).

PREDICTORS

We measured baseline clinical characteristics between January 1997 and June 2000 by using electronic medical records and patients' histories of hospitalization.

OUTCOMES & MEASUREMENTS

We calculated adjusted hazard ratios and concordance statistics for progression to RRT, mortality, and the composite by using Cox regression.

RESULTS

Patients (n = 6,541) were followed up for up to 5 years. We observed 1.6 progressions to RRT/100 person-years and 11.4 deaths/100 person-years. The 6 characteristics of age, sex, eGFR, diabetes, hypertension, and anemia predicted RRT effectively (c statistic, 0.91). However, hypertension and age predicted in the opposite direction for mortality and its composite end point. The c statistic decreased: mortality (0.70), mortality and RRT (0.71).

LIMITATIONS

Characteristics were measured without a protocol; extensive missing data prevented the evaluation of known risk factors (eg, proteinuria).

CONCLUSIONS

Predicting RRT effectively requires a separate risk score. Predicting the composite end point would favor characteristics that predict mortality because it is 7 times as common as RRT.

Treating anemia of chronic kidney disease in the primary care setting: cardiovascular outcomes and management recommendations

Anemia is an underrecognized but characteristic feature of chronic kidney disease (CKD), associated with significant cardiovascular morbidity, hospitalization, and mortality. Since their inception nearly two decades ago, erythropoiesis-stimulating agents (ESAs) have revolutionized the care of patients with renal anemia, and their use has been associated with improved quality of life and reduced hospitalizations, inpatient costs, and mortality. Hemoglobin targets >/=13 g/dL have been linked with adverse events in recent randomized trials, raising concerns over the proper hemoglobin range for ESA treatment. This review appraises observational and randomized studies of the outcomes of erythropoietic treatment and offers recommendations for managing renal anemia in the primary care setting.

The fascinating but deceptive ferritin: to measure it or not to measure it in chronic kidney disease?

Although the emergence of erythropoiesis-stimulating agents has revolutionized the anemia management of chronic kidney disease (CKD) in the past two decades, strategies to assess iron (Fe) status and to provide Fe supplementation have remained indistinct. The reported cases of hemochromatosis in dialysis patients from the pre-erythropoiesis-stimulating agent era along with the possible associations of Fe with infection and oxidative stress have fueled the "iron apprehension." To date, no reliable marker of Fe stores in CKD has been agreed on. Serum ferritin continues to be the focus of attention. Almost half of all maintenance hemodialysis patients have a serum ferritin >500 ng/ml. In this ferritin range, Fe supplementation currently is not encouraged, although most reported hemochromatosis cases had a serum ferritin >2000 ng/ml. The moderate-range hyperferritinemia (500 to 2000 ng/ml) seems to be due mostly to non-Fe-related conditions, including inflammation, malnutrition, liver disease, infection, and malignancy. Recent epidemiologic studies have shown that a low, rather than a high, serum Fe is associated with a poor survival in maintenance hemodialysis patients. In multivariate adjusted models that mitigate the confounding effect of malnutrition-inflammation, serum ferritin <1200 ng/ml and Fe saturation ratio in 30 to 50% range are associated with the greatest survival in maintenance hemodialysis patients. Although ferritin is a fascinating molecule, moderate hyperferritinemia is a misleading marker of Fe stores in patients with CKD. It may be time to revisit the utility of serum ferritin in CKD and ask ourselves whether its measurement has helped us or has caused more confusion and controversy.

Stability of target hemoglobin levels during the first year of epoetin treatment in patients with chronic kidney disease

BACKGROUND AND OBJECTIVES

Instability of hemoglobin levels during epoetin therapy is a new problem in hemodialysis. We evaluated extent and correlates of time in target, that is, the time spent with hemoglobin > or = 11 g/dl during the first year of epoetin and its association with renal survival.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data were collected in 917 visits for 12.0 mo in 119 patients with chronic kidney disease; thereafter, patients started renal survival analysis for 10.1 mo. At baseline, hemoglobin was 10.0 +/- 0.8 g/dl and GFR was 22.1 +/- 14.2 ml/min per 1.73 m2.

RESULTS

Hemoglobin target, reached in 1.5 mo, was steadily maintained in only 24% of patients. Time in target was not merely due to differences in time to target; after first achievement of target, in fact, a reduction of hemoglobin < 11 g/dl occurred in 51% of patients. At multivariate analysis, male gender, basal GFR and hemoglobin levels, first epoetin dose, and iron supplementation were directly associated with length of time in target. A lower risk for renal death (dialysis n = 53; death n = 8) was detected in the higher tertile of time in target (11.3 mo) versus lower tertile (3.2 mo). This difference persisted at Cox analysis after adjustment for age, gender, GFR, BP, and proteinuria.

CONCLUSIONS

In chronic kidney disease, time in target during the first year of epoetin therapy is frequently short depending not only on time to target but also on post-target hemoglobin reductions, correlates with male gender, timing, and intensity of initial therapy and is coupled with better renal survival.

Anemia is associated with mortality in kidney-transplanted patients--a prospective cohort study

Although anemia is a known risk factor of mortality in several patient populations, no prospective study to date has demonstrated association between anemia and mortality in kidney-transplanted patients. In our prospective cohort study (TransQol-HU Study), we tested the hypothesis that anemia is associated with mortality and graft failure (return to dialysis) in transplanted patients. Data from 938 transplanted patients, followed at a single outpatient transplant center, were analyzed. Sociodemographic parameters, laboratory data, medical history and information on comorbidity were collected at baseline. Data on 4-year outcome (graft failure, mortality or combination of both) were collected prospectively from the patients' charts. Both mortality and graft failure rate during the 4-year follow-up was significantly higher in patients who were anemic at baseline (for anemic vs nonanemic patients, respectively: mortality 18% vs. 10%; p < 0.001; graft failure 17% vs 6%; p < 0.001). In multivariate Cox proportional hazard models the presence of anemia significantly predicted mortality (HR = 1.690; 95% CI: 1.115-2.560) and also graft failure (HR = 2.465; 95% CI: 1.485-4.090) after adjustment for several covariables. Anemia, which is a treatable complication, is significantly and independently associated with mortality and graft failure in kidney-transplanted patients.

Impact of kidney bone disease and its management on survival of patients on dialysis

Despite the enormous cardiovascular disease epidemic and poor survival among individuals with chronic kidney disease (CKD), traditional risk factors such as hypercholesterolemia, hypertension, and obesity appear not as relevant as was previously thought, nor would their management improve survival in patients with CKD who are undergoing dialysis. On the contrary, kidney disease wasting (KDW) (also known as the malnutrition-inflammation complex), renal anemia, and kidney bone disease (KBD) appear to be the 3 most important nontraditional risk factors associated with cardiovascular disease in CKD. KBD-associated hyperparathyroidism may contribute to worsening refractory anemia and KDW/inflammation. The main cause of secondary hyperparathyroidism is active vitamin D deficiency. Hence, treatment of patients with KBD with vitamin D analogs, especially those with lesser effects on calcium and phosphorus such as paricalcitol, may be the most promising option for improving CKD outcomes. By conducting survival analyses in a 2-year (7/2001 to 6/2003) cohort of 58,058 patients on hemodialysis, we recently found that associations between high serum parathyroid hormone and increased death risk were masked by the demographic and clinical characteristics of patients, and that alkaline phosphatase had an incremental association with mortality. Administration of paricalcitol was associated with improved survival in time-varying models. We now present additional subgroup analyses that show that administration of any dose of paricalcitol, when compared with no paricalcitol, is associated with better likelihood of survival in virtually all subgroups of patients on hemodialysis. Because these associations may be secondary to bias by indication, randomized clinical trials are necessary to verify the findings of this and similar observational studies.

Predicting initiation and progression of chronic kidney disease: Developing renal risk scores

Epidemiological studies have raised awareness of the problem of undiagnosed chronic kidney disease (CKD) and suggest that early identification and treatment will reduce the global burden of patients requiring dialysis. This has highlighted the twin problems of how to identify subjects for screening and target intervention to those with CKD most likely to progress to end-stage renal disease. Prospective studies have identified risk factors for CKD in the general population as well as risk factors for progression in patients with established CKD. Risk factors may thus be divided into initiating factors and perpetuating factors, with some overlap between the groups. In this paper, we review current data regarding CKD risk factors and illustrate how each may impact upon the mechanisms underlying CKD progression to accelerate loss of renal function. We propose that these risk factors should be used as a basis for developing a renal risk score, analogous to the Framingham risk score for ischemic heart disease, which will allow accurate determination of renal risk in the general population and among CKD patients.