Anemia management of adult hemodialysis patients in the US results: from the 1997 ESRD Core Indicators Project

Prediction of Pharmacokinetics of Antibiotics in Patients with End-Stage Renal Disease

A novel and convenient method to predict the pharmacokinetics of several kinds of antibiotic agents in patients with end-stage renal disease (ESRD) was examined based on the in vitro extraction ratios and pharmacokinetic parameters in healthy volunteers. The dializability of 17 antibiotic agents in 4% human serum albumin solution were determined using a high-performance hemodialytic membrane for clinical use. We assumed that the off-hemodialysis clearance approximated the non-renal clearance, while the on-hemodialysis clearance was considered to be sum of the off-hemodialysis clearance and the hemodialytic clearance. The estimated on- and off-hemodialysis clearances were compared with the ones observed in ESRD patients. In order to confirm the method prospectively, an in vivo pharmacokinetic study was performed in dogs with mercury chloride-induced experimental renal failure. The in vitro extraction ratios of 9 beta-lactams were broadly ranged from 10.9 to 75.6% depending on their physicochemical properties. In contrast, those of the other antibiotics were consistent with their chemical classes: 60.5-63.2% for fluoroquinolone, 48.8-51.1% for aminoglycoside and 18.7-25.6% for glycopeptide. Both the estimated on- and off-hemodialysis clearances of the 17 antibiotics coincided well with the observed values in the literature, regardless of their physicochemical and pharmacokinetic properties. The validity and applicability of this method to three cefems, cefmetazole, cefotaxime and cefoperazone, was prospectively confirmed in the animal study. In conclusion, this new method enables the prediction of the on- and off-hemodialysis clearances of several kinds of antibiotics in ESRD patients from minimal information of their pharmacokinetics in healthy subjects and their in vitro dializability.

Efficacy and immunogenicity of novel erythropoietic agents and conventional rhEPO in rats with renal insufficiency

Recombinant human erythropoietin (rhEPO) is used to treat anemia in chronic renal insufficiency. Erythropoietin (EPO) immunogenicity can lead to EPO-resistant anemia. Conjugating proteins with polyethylene glycol (PEG) can prolong elimination half-life and diminish protein immunogenicity. We investigated the efficacy of new erythropoietic agents, synthesized by single (Ro 50-3821) and multiple (MIX) integrations of PEG and succinimidyl butanoic acid with rhEPO, in rats with chronic renal insufficiency. Sprague-Dawley rats with surgically induced renal insufficiency received Ro 50-3821 or MIX subcutaneously (s.c.) over 4-12 weeks compared to rhEPO and NaCl. Hemoglobin and antibody levels served as primary efficacy and safety variables. Dosing intervals and dose-response characteristics were investigated. Ro 50-3821 (2.5 microg/kg once weekly) increased hemoglobin levels by 7 g/dl after 4 weeks compared to 1 g/dl in NaCl controls (P<0.05). MIX (2.5 microg/kg once weekly) and rhEPO (0.25 microg/kg three times weekly) increased hemoglobin levels by 3 g/dl. Ro 50-3821 administered for 12 weeks (0.75 microg/kg once weekly) increased hemoglobin levels (from 13 to 19 g/dl) more effectively than rhEPO (0.75 microg/kg once weekly, decline from 13 to 11 g/dl, P<0.05). No antibodies against Ro 50-3821 were detected after 12 weeks of treatment. Antibodies against rhEPO were seen in 69% of animals (P<0.00001). Ro 50-3821 increased hemoglobin levels with once weekly s.c. dosing. Multiple pegylated EPO is less effective. In rats, rhEPO failed to increase hemoglobin levels with once weekly long-term dosing. Antibody formation following rhEPO may explain this finding. Therefore, Ro 50-3821 may provide important clinical advantages compared to unpegylated EPO. It can be administered in longer dosing intervals and has a lower risk of unfavorable immunological responses.

Trends in Intravenous Iron Use Among Dialysis Patients in the United States (1994-2002)

BACKGROUND

Two new intravenous (IV) iron products, ferric gluconate and iron sucrose, recently were approved for use in the United States. We report trends in IV iron use in both incident (1994 to 2001) and prevalent (1994 to 2002) Medicare US dialysis patients.

METHODS

Included patients had Medicare as a primary payer. Recombinant human erythropoietin doses, IV iron use, and hemoglobin data were obtained from Medicare outpatient files. The most recent cohorts included 241,770 prevalent hemodialysis (HD) patients in 2002 and 11,744 incident HD patients in 2001.

RESULTS

For incident HD patients in the first 9 months of dialysis therapy, the percentage of patients administered IV iron increased sharply between 1994 and 1997 and then increased gradually between 1997 and 2001. In 2002, a total of 84.4% of HD and 19.3% of peritoneal dialysis (PD) patients were administered IV iron. Ferric gluconate use increased slowly in 2000, increased from 5.7% to 18.6% from December 2000 to January 2001, increased to 29.8% in April 2002, and was 23.3% in December 2002. Iron sucrose use increased to 26% by December 2002. The absolute monthly percentage of HD patients administered IV iron dextran decreased from 49.6% in January 2000 to 3.6% in December 2002.

CONCLUSION

In US patients with end-stage renal disease, IV iron use has increased, although slowly, from 1997 to 2002. Ferric gluconate and iron sucrose have become the predominant form of therapy. IV iron therapy was used in a much smaller percentage of PD compared with HD patients, and racial and geographic variability was observed.

The effect of a change in epoetin alfa reimbursement policy on anemia outcomes in hemodialysis patients

In 1997, the Health Care Financing Administration Hematocrit Measurement Audit (HMA) program initiated use of a 3-month rolling average hematocrit (Hct) level for reimbursement of epoetin claims in hemodialysis patients, with denial of payment when this value exceeded 36.5%. This study evaluated the impact of the HMA program on anemia-related outcomes in hemodialysis patients. An observational, retrospective study of 987 hemodialysis patients from 11 dialysis centers in the United States was performed, collecting data between October 1996 and December 1997. Centers were selected from a pool of nearly all facilities in the United States, which during May 1997 satisfied one of two criteria: greater than 75% of patients at the facility had mean Hct level of > or =33% (Group A) or fewer than 50% of patients at the facility had mean Hct level of > or =33% (Group B). Each facility maintained its own anemia management practices without specific anemia management interventions as part of this study. Hct level, hemoglobin (Hb) level, and epoetin dose were analyzed to compare the pre-HMA period (October 1996 to May 1997) to the HMA period (June to December 1997) and/or for each of the five quarters of the study period. The primary study endpoint was the percentage of patients with Hct levels of > or =33% during each study quarter. The mean Hct level at baseline was 34% in Group A and 33.4% in Group B (p = 0.01). Hct levels, which were increasing before implementation of the HMA program, decreased during the HMA period (p < 0.001 and p = 0.013 in Groups A and B, respectively). The percentage of patients in Groups A and B with mean quarterly Hct levels of > or =33% decreased during the last quarter of the HMA implementation period compared to the quarter immediately preceding the start of the HMA program (p < 0.001 for both comparisons). Changes in Hb levels were similar to those seen in Hct levels. The mean epoetin dose administered decreased from 13,090 U/week at the start of the study to 11,884 U/week immediately before the HMA program took effect (p < 0.05). The HMA program adversely affected anemia treatment outcomes, regardless of whether dialysis units before HMA implementation had <50% of patients with a Hct level of > or =33% or had >75% of patients with a Hct level of > or =33%. The decline in mean weekly dose of epoetin was likely a result of withholding doses out of concern among providers about risk of reimbursement denial.

National profile of practice patterns for hemodialysis vascular access in the United States

The Centers for Medicare & Medicaid Service's (CMS), national End-Stage Renal Disease (ESRD) Clinical Performance Measures (CPM) Project is a data collection initiative to identify opportunities for improvement of care to adult, Medicare maintenance dialysis beneficiaries. This analysis of 1999 CPM data characterizes the profile of hemodialysis vascular access in the United States and identifies determinants of vascular access type 2 yr after the translation of vascular access clinical practice guideline statements into national CPMs. CPM data were collected during October to December 1999 and stratified by the 18 regional ESRD networks. Univariate and multivariable analyses were conducted to examine associations of access type with demographic, laboratory, and geographic variables. Multivariable logistic regression analyses were performed to identify independent variables associated with access type. A total of 8154 hemodialysis patients were sampled; 17% (n = 1399) were incident. Twenty-eight percent were dialyzed through an autologous arteriovenous fistula (AVF), 49% through a prosthetic graft (AVG), and 23% through a percutaneous catheter. Independent predictors of having a catheter for hemodialysis were female gender, white race, incident to hemodialysis status, and lower hemoglobin and serum albumin. For patients with a fistula or AVG, female gender (odds ration [OR], 2.46 [2.18 to 2.78]) and black race (OR, 1.70 [1.50 to 1.93]) were the strongest predictors of dialysis through an AVG. Other predictors of dialysis through an AVG were older age, increased body mass index (BMI), diabetes mellitus as the cause of ESRD, and lower serum albumin. Even in adjusted analyses, there was significant geographic variability with respect to hemodialysis access type. Despite translation of practice guidelines for hemodialysis vascular access into national CPMs, there is substantial geographic variability and gender and racial disparity in angioaccess allocation in the United States. Quality improvement strategies to improve the prevalence of fistulae should focus on selected regions and include physician education about their practice patterns and potential biases.

Trends in anemia management among US hemodialysis patients

This study was undertaken to describe the relationship between hematocrit (Hct) and changes in the prescribed dose of erythropoietin (EPO) as well as selected patient and process care measures across annual national samples of hemodialysis patients from 1994 to 1998. This study uses the cohorts identified in the ESRD Core Indicators Project, random samples of 6181, 6241, 6364, 6634, and 7660 patients, stratified by ESRD Networks drawn for each year from 1994 to 1998. Patient demographic and clinical information was collected from October to December for each year. Surrogates of iron stores and patterns of iron and EPO administration were profiled from 1996 to 1998. Multivariable stepwise linear regression analyses were performed to adjust for potential confounding variables and to identify independent variables associated with Hct and EPO dose. Mean Hct and EPO dose increased each year from 31.1 +/- 5.2% to 34.1 +/- 3.7% and from 58.2 +/- 41.8 U/kg to 68.2 +/- 55.0 U/kg, respectively (P = 0.0001). Increasing Hct was positively associated with male gender, more years on dialysis, older age, higher urea reduction ratio and transferrin saturation, prescription of intravenous iron, and lower ferritin and EPO dose in multivariable models (all P = 0.0001). Male gender, older age, diabetes, higher Hct, and increasing weight, urea reduction ration, and transferrin saturation were associated with lower EPO doses (all P < 0.01). Conversely, intravenous EPO and iron were associated with higher prescribed EPO doses (all P = 0.0001). Although increasing Hct is associated with decreasing EPO dose at the patient level, the increase in Hct seen across years among the cohorts of hemodialysis patients in the United States has been associated with increasing doses of EPO at the population level.

Delivery of erythropoietin with a needleless injection system during hemodialysis maintains plasma levels

Recent Occupational Safety and Health Administration guidelines require the implementation of needleless systems in dialysis units in the state of California. It is not known whether needleless systems deliver medication as well as traditional low dead-space needle/syringes. The purpose of this study was to compare the delivery of recombinant human erythropoietin (rHuEpo) by a needleless system (Medic Plastic Anti-Stick Needle/Connector, Medisystems, Seattle, WA) with delivery using a traditional low dead-space needle/syringe. We also studied the Medisystems High Flow venous chamber with integral injection site that is designed to prevent the formation of a separate serum layer within which rHuEpo may become trapped. There was no significant difference in the mean serum rHuEpo concentration achieved by either the needleless system, or traditional low dead-space needle/syringe, whether using the venous chamber's integral injection site or the postvenous chamber in-line injection site. This study demonstrates for the first time that a needleless system of delivery can reliably achieve serum rHuEpo comparable to traditional low dead-space needle/syringes.

Increase in plasma esterified F2-isoprostanes following intravenous iron infusion in patients on hemodialysis

BACKGROUND

In epoetin-treated dialysis patients, currently iron is administered by the intravenous route to maintain optimum erythropoiesis. However, rapid infusion of iron in excess of transferrin binding capacity can lead to the availability of unbound iron that can theoretically catalyze peroxidation of lipids, such as low-density lipoprotein (LDL), which when oxidatively modified is proinflammatory and promotes atherogenesis.

METHODS

To address this issue, our study used one of the most specific measures of lipid peroxidation available, namely gas chromatography/mass spectometry (GC/MS) analysis of F2-isoprostanes. Using a prospective design, blood samples were collected 15 minutes before (pre) and 30 minutes after (post) a one-hour infusion of 700 mg bolus of intravenous iron in 22 adult home-hemodialysis patients on a non-hemodialysis day.

RESULTS

With iron-dextran infusion, serum iron markedly increased (mean +/- SE, 42 +/- 4 vs. 311 +/- 92 microg/dL, P < 0.0001) and exceeded the transferrin saturation of 100% in 22 out of 22 patients (pre 23 +/- 3 vs. post 165 +/- 8%, P < 0.0001). Plasma concentrations of free F2-isoprostanes did not change significantly following infusion of iron (pre 40 +/- 5 vs. post 39 +/- 6 pg/mL). However, levels of F2-isoprostanes esterified in plasma lipoproteins increased significantly in the postinfusion samples (pre 199 +/- 19 vs. post 233 +/- 25 pg/mL, P < 0.004). Pre-infusion levels of serum iron correlated directly with pre-infusion levels of esterified F2-isoprostanes (r = 0.56, P = 0.008), which persisted in the postinfusion period (r = 0.43, P = 0.04). However, there was no correlation between esterified F2-isoprostanes and serum ferritin levels. In the last four patients in whom blood samples were collected five hours after the intravenous iron infusion, there were further increases in esterified F2-isoprostanes that very closely correlated with postinfusion serum iron levels (r = 0.99, P = 0.013). In a control study, the in vitro addition of iron dextran to blood samples did not increase free or esterified F2-isoprostanes, suggesting that the increase in esterified F2-isoprostanes seen in vivo after iron infusion in patients is not due to a procedural artifact.

CONCLUSION

Collectively our data suggest that high levels of serum iron appearing soon after a large bolus of iron infusion is associated with significant, albeit modest, increases in levels of F2-isoprostanes esterified in plasma lipoproteins that tended to increase with time. Although it is uncertain whether this degree of lipid peroxidation may have deleterious effects, it may be sagacious to explore whether this can be prevented by slow infusion of frequent smaller doses of iron and, if necessary, along with administration of antioxidants.

Anemia and iron target realization in 1998: clinical management of anemia in 1,639 patients on hemodialysis

Anemia management in hemodialysis patients continues to evolve, and recently, greater emphasis has been placed on the wider use of intravenous iron to maintain adequate iron levels. This survey provides scarcely available yet potentially useful information on the clinical treatment of anemia in a large cohort of hemodialysis patients. The erythropoietin and iron administration details and pertinent laboratory measurements from 1,639 patients were analyzed for the month of December, 1998. A standardized protocol had been used in that erythropoietin was begun at a total weekly dose of 150 U/kg IV or 100 U/kg subcutaneously and was then adjusted to maintain a hematocrit (Hct) of 33-36%. Iron supplements, oral, IV, or both, were administered to maintain percent transferrin saturation (TSAT) at 20-30% and/or a serum ferritin of 100-500 ng/ml. No intravenous iron was administered if the ferritin was more than 500 ng/ml. Although 82% of patients were on iron supplementation and, among them, 58% were on IV iron, the percentage of patients with TSAT >20, i.e., bioavailable iron, was only 51%. The serum ferritin was high at 498 +/- 10 ng/ml (mean +/- SEM) and 88% and 10% of patients had serum ferritin >100 and >1,000 ng/ml, respectively, suggestive of sequestration of part of the infused iron. Erythropoietin was administered to 96% of patients, 99.5% by IV route. The latter was consistent with the US dialysis population at large but in variance with DOQI preference for the subcutaneous route. The target Hct range of 33-36 was found in 33%, with a mean Hct of 34.0 +/- 0.12. When the data were reanalyzed by excluding patients who had not been receiving erythropoietin and had not been on dialysis for at least 3 months, the percentage of patients achieving the target Hct increased to 37%. Paired analysis of 875 patients present in 1996 and 1998 showed that, although there was a marked increase in the use of IV iron, the improvement in anemia was modest, and there was evidence for increased iron accumulation. In summary, this 1998 survey on the clinical practice of anemia management in a large hemodialysis population indicates that there is a marked increase in need-based IV iron usage that was associated with modest improvement in anemia and evidence for increased iron storage. A maintenance iron dosing protocol with smaller doses of iron, such as 25 mg of iron dextran per hemodialysis, may make bioavailable iron continuously present for erythropoiesis, yet may reduce the chance for iron catalyzed lipid peroxidation and tissue iron deposition.

Coordination of care in disease management: opportunities and financial issues

Patients with end-stage renal disease (ESRD) and pre-ESRD require higher utilization of health care resources. Current reimbursement modalities contribute to the fragmentation of care, and inadequate financial information obscures the fiscal impact disease management's coordination of care can have for this population. Ignoring the extreme costs of the first 3 months of hemodialysis underestimates costs by as much as 16%. Potential areas of coordination and the financial benefits are discussed. In each venue of the care settings of a patient with chronic renal failure (CRF) they may receive excellent service. Too often there is not optimal coordination of care between these venues, and in fact the fragmentation of care can cause unnecessary wear and tear on the patient, and increases the overall expense to a health care system. Understanding sources of fragmentation, reimbursement effects, and potential corrections will enhance the patient's voyage through the system. This article provides some examples of the discoordination that presently exists and financial implications especially during the transition onto dialysis. In patients with end-stage renal disease (ESRD), each arena of care has criteria established to quantitate quality. None of the settings, whether it is the dialysis unit, the hospital, the skilled nursing facility, or the physician's office, exists in the absence of regulations. These may be state or federal, National Council on Quality Assurance (NCQA), Health Plan Employer Data and Information Set (HEDIS), water standards, Occupational Safety and Health Administration (OSHA), fire codes, physician peer review, Medicare billing, Health Care Finance Administration (HCFA), the ESRD networks, credentialing, health maintenance organization (HMO) insurance requirements, pharmacy benefits and formularies, safe harbors, "antikickback," or National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF-DOQI) guidelines. For all the providers of care, the other critical component is the ability to have adequate income to stay in business, and make a profit. Each becomes very astute at working within the confines of the regulatory restrictions to provide good care. However, the continuity of care cannot be the overwhelming issue for many of the providers. The only person that is involved in every arena is the patient. The only provider that currently crosses over most arenas is the nephrologist. But the other element that exists in each arena is a payer.

Diagnosis and management of iron deficiency in chronic dialysis patients

Tests have become available that not only give an index of iron stores and availability but also provide an integrated assessment of the efficacy of its utilization. This has allowed the revision of previously accepted criteria of iron deficiency as well as the most appropriate strategies for iron administration. By optimizing the response to erythropoietin, target haemoglobin levels may be reached with smaller doses, resulting in substantial savings.