Hypophosphatemia Associated with Intravenous Iron Therapies for Iron Deficiency Anemia: A Systematic Literature Review

Background

Iron deficiency anemia (IDA) is a prevalent yet underdiagnosed condition with a significant impact on quality of life. Oral iron supplementation is often poorly tolerated or yields inadequate response, requiring the use of intravenous iron (IVI) in some patients. Administration of certain IVI preparations has been associated with decreases in serum phosphate levels and clinically significant hypophosphatemia, which has been reported to lead to adverse events including serious fatigue and osteomalacia.

Objective

The purpose of this study was to systematically assess the prevalence, clinical consequences, and reporting of treatment-emergent hypophosphatemia within literature investigating IVI therapies marketed in the United States (US).

Methods

A systematic literature review (SLR) was conducted using the PubMed database to identify publications reporting serum phosphate levels or rates of hypophosphatemia within adult IDA patient populations receiving current US-marketed IVIs.

Results

The SLR yielded 511 unique publications, with 40 records meeting the final inclusion criteria. Most studies did not report phosphate monitoring methodology or an explicit definition of hypophosphatemia. Hypophosphatemia rates ranged from 0.0% to 92.1% for ferric carboxymaltose (FCM), 0.0% to 40.0% for iron sucrose, 0.4% for ferumoxytol, and 0.0% for low-molecular-weight (LMW) iron dextran. Randomized controlled studies described hypophosphatemia as “asymptomatic” or did not report on other associated sequelae. Eleven case reports detailed treatment-emergent hypophosphatemia in patients treated with FCM. Patients with acute hypophosphatemia primarily developed severe fatigue; those with repeated FCM dosing developed chronic hypophosphatemia associated with osteomalacia and bone deformities.

Conclusion

Studies analyzed in this SLR reported a range of hypophosphatemia rates, with the highest consistently seen in patients treated with FCM. Across the clinical literature, there appeared to be minimal standardization of phosphate monitoring and definitions of hypophosphatemia. Although multiple cases have documented serious clinical consequences of hypophosphatemia associated with certain IVIs, current trials neither consistently nor adequately assess the frequency and severity of treatment-emergent hypophosphatemia and may underestimate its prevalence.

Correction to: The Ferumoxytol for Anemia of CKD Trial (FACT)-a randomized controlled trial of repeated doses of ferumoxytol or iron sucrose in patients on hemodialysis: background and rationale

Following publication of the original article [1], the authors reported that one of the authors' name is spelled incorrectly. In this Erratum the incorrect and correct author name are shown. The original publication of this article has been corrected.

Efficacy and safety of IV ferumoxytol for iron deficiency anemia in patients with cancer

Purpose

Iron deficiency anemia (IDA) is common in cancer patients due to blood loss and inflammation. Many do not tolerate oral iron or adequately respond. Intravenous (IV) iron is commonly used as an adjunct to erythropoiesis-stimulating agents; data on the use of IV iron monotherapy in these patients are limited. This study aimed to evaluate IV ferumoxytol for the treatment of cancer patients with IDA with a history of unsatisfactory oral iron therapy or in whom oral iron could not be used.

Patients and methods

This post hoc analysis of pooled data from two multicenter, randomized, controlled, Phase III trials evaluating IV ferumoxytol (510 mg ×2) vs placebo or iron sucrose (200 mg ×5) included a subgroup of 98 patients with cancer that the investigator identified as the primary cause of their IDA, or with cancer whose IDA was attributed to another comorbid condition (ferumoxytol, n=75; iron sucrose, n=13; placebo, n=10). Gastrointestinal cancers were most common (42), followed by breast (14), cervix (ten), and lung (nine). The primary endpoint was the mean change in hemoglobin (Hgb) from baseline to week 5.

Results

At week 5, both ferumoxytol and iron sucrose produced significant increases in Hgb from baseline (1.8 g/dL [P<0.0001] and 1.9 g/dL [P=0.002], respectively). During the studies, 45 patients received chemotherapy, 19 with platinum-based regimens. Erythropoiesis-stimulating agent doses were neither increased >20% nor initiated in any treatment group. Overall rates of adverse events and serious adverse events in the cancer subgroup mirrored those in the overall study population.

Conclusion

Monotherapy with IV iron appears to be an effective option for cancer patients with IDA who do not respond to or cannot tolerate oral iron therapy.

Cost-effectiveness analysis of intravenous ferumoxytol for the treatment of iron deficiency anemia in adult patients with non-dialysis-dependent chronic kidney disease in the USA

Objective

Ferumoxytol has demonstrated superior efficacy compared with oral iron in treating iron deficiency anemia in chronic kidney disease (CKD) patients. However, an economic evaluation of ferumoxytol has not been conducted. The aim of this study was to analyze the cost-effectiveness of treating iron deficiency anemia in adult non-dialysis-dependent CKD patients with ferumoxytol as compared with oral iron, alone or in combination with erythropoietin-stimulating agents (ESAs).

Methods

A decision analytic model compared health outcomes and costs associated with 5-week outpatient treatment of adult non-dialysis-dependent CKD patients with ferumoxytol or oral iron, each as monotherapy or in combination with ESAs in the USA. Direct costs include the following: drug acquisition and administration, adverse events, and medical management. Efficacy was determined as mean increase in hemoglobin (g/dL) from baseline over the 5-week period. Clinical inputs were derived from patient-level data from two Phase III randomized controlled trials of ferumoxytol vs. oral iron in non-dialysis-dependent CKD patients, and cost inputs from RED BOOK™ and Centers for Medicare and Medicaid Services data. Sensitivity analyses were performed to identify cost drivers and assess the stability of results.

Results

The 5-week treatment cost was $2,489, $5,216, $1,298, and $4,263 per patient for ferumoxytol, ferumoxytol with ESAs, oral iron, and oral iron with ESAs, respectively. The corresponding incremental costs per g/dL increase in hemoglobin, relative to ferumoxytol alone, were $398, $3,558, and $4,768 per patient. Efficacy was the main driver of cost-effectiveness for all treatments. Adverse event and medical management costs were the principal drivers of oral iron monotherapy costs, while drug acquisition substantially contributed to the overall cost for the remaining treatments.

Conclusion

These results suggest that ferumoxytol is a cost-effective treatment for iron deficiency anemia in non-dialysis-dependent CKD patients over a 5-week period compared with oral iron with or without ESAs. Ferumoxytol is more cost-effective as monotherapy.

Ferumoxytol versus iron sucrose treatment: a post-hoc analysis of randomized controlled trials in patients with varying renal function and iron deficiency anemia

Background

Iron deficiency anemia is highly prevalent in patients with chronic kidney disease and is often treated with intravenous iron. There are few trials directly comparing the safety and efficacy of different intravenous iron products.

Methods

This post-hoc analysis pooled data from 767 patients enrolled in two randomized, controlled, open-label trials of similar design comparing the treatment of iron deficiency anemia with ferumoxytol and iron sucrose across patients with all stages of renal function. One trial was conducted in adults with CKD either on or not on dialysis and the second in adults with IDA of any underlying cause and a history of unsatisfactory oral iron therapy or in whom oral iron could not be used who had normal to no worse than moderately impaired renal function. Patients were categorized by chronic kidney disease stage (i.e., estimated glomerular filtration rate), and the primary efficacy endpoint was the mean change in hemoglobin from Baseline to Week 5.

Results

The overall incidence of adverse events was numerically lower in ferumoxytol-treated patients compared to those treated with iron sucrose (42.4 vs. 50.2 %, respectively); the incidence of treatment-related adverse events was generally similar between the two treatment groups (13.6 vs. 16.0 %, respectively). Adverse events of Special Interest (i.e., hypotension, hypersensitivity) occurred at lower rates in those treated with ferumoxytol compared to those treated with iron sucrose (2.5 vs. 5.3 %, respectively). Overall, mean hemoglobin increased in both treatment groups, regardless of degree of renal insufficiency, although greater increases were seen among those with less severe kidney damage. Mean increases in hemoglobin from Baseline to Week 5 were significantly greater with ferumoxytol than with iron sucrose treatment in the subgroup with an estimated glomerular filtration rate ≥90 mL/min (Least Squares mean difference = 0.53 g/dL; p < 0.001). There were no other consistent, significant differences in hemoglobin levels between treatment groups for the other chronic kidney disease categories except for isolated instances favoring ferumoxytol.

Conclusions

The efficacy and safety of ferumoxytol is at least comparable to iron sucrose in patients with varying degrees of renal function.

Trial registration

(CKD-201; ClinicalTrials.gov identifier: NCT01052779; registered 15 January, 2010), (IDA-302; ClinicalTrials.gov identifier: NCT01114204; registered 29 April, 2010).

Electronic supplementary material

The online version of this article (doi:10.1186/s12878-016-0060-x) contains supplementary material, which is available to authorized users.

Ferumoxytol versus placebo in iron deficiency anemia: efficacy, safety, and quality of life in patients with gastrointestinal disorders

Introduction

Iron deficiency anemia (IDA) is common in patients with gastrointestinal (GI) disorders and can adversely affect quality of life. Oral iron is poorly tolerated in many patients with GI disorders. Ferumoxytol is approved for the intravenous treatment of IDA in patients with chronic kidney disease. This study aimed to evaluate the efficacy and safety of ferumoxytol in patients with IDA and concomitant GI disorders.

Patients and methods

This analysis included 231 patients with IDA and GI disorders from a Phase III, randomized, double-blind, placebo-controlled trial evaluating ferumoxytol (510 mg ×2) versus placebo in patients who had failed or were intolerant of oral iron therapy. The primary study end point was the proportion of patients achieving a ≥20 g/L increase in hemoglobin (Hgb) from baseline to Week 5. Other end points included mean change in Hgb, proportion of patients achieving Hgb ≥120 g/L, mean change in transferrin saturation, and patient-reported outcomes (PROs).

Results

Significantly more patients with IDA receiving ferumoxytol achieved a ≥20 g/L increase in Hgb versus placebo (82.1% vs 1.7%, respectively; P<0.001). Mean increase in Hgb (28.0 g/L vs −1.0 g/L, respectively; P<0.001) significantly favored ferumoxytol treatment. Ferumoxytol-treated patients demonstrated significantly greater improvements than placebo-treated patients relative to their very poor baseline PRO scores posttreatment, including improvements in the Functional Assessment of Chronic Illness Therapy–Fatigue questionnaire and various domains of the 36-Item Short-Form Health Survey. Ferumoxytol-treated patients had a low rate of adverse events.

Conclusion

In this study, ferumoxytol was shown to be an efficacious and generally well-tolerated treatment option for patients with IDA and underlying GI disorders who were unable to use or had a history of unsatisfactory oral iron therapy.

Cognitive effects of oxybutynin chloride topical gel in older healthy subjects: a 1-week, randomized, double-blind, placebo- and active-controlled study

BACKGROUND AND OBJECTIVE

Oxybutynin is a common antimuscarinic therapy for overactive bladder. Transdermally administered oxybutynin chloride topical gel 10% (OTG) has a low propensity for anticholinergic adverse effects and possibly also a low risk of cognitive impairment. A randomized, double-blind, placebo- and active-controlled study evaluated the effects of OTG on cognitive and psychomotor functions in older healthy adults.

METHODS

Healthy adults aged 60-79 years were assigned randomly (1:1:1) to 1-week's treatment with OTG (1 g [100 mg oxybutynin] applied once daily on rotating sites of upper arms/shoulders, abdomen or thighs) plus oral placebo, immediate-release oxybutynin (OXB-IR; 5 mg capsule three times/day) plus placebo gel, or double placebo. Delayed recall Name-Face Association Test (NFAT) score was the primary end point. Treatments were compared by analysis of covariance.

RESULTS

Of 152 participants (mean age, 68 years), 49 received OTG, 52 OXB-IR and 51 placebo. NFAT Delayed Recall tests revealed no significant treatment differences (overall, p = 0.2733; OTG vs placebo, p = 0.1551; OXB-IR vs placebo, p = 0.1767). However, a significant effect (p = 0.0294) was noted for the Misplaced Objects Test, with scores declining only for OXB-IR. Approximately twice as many participants receiving OXB-IR (n = 10) as those receiving OTG (n = 5) or placebo (n = 6) showed a significant decline (≥6 points) in Total Recall score for the Hopkins Verbal Learning Test-Revised. No significant effects on psychomotor reaction time were observed. The most common adverse event, dry mouth, occurred in 6.1%, 73.1% and 7.8% of participants receiving OTG, OXB-IR and placebo, respectively.

CONCLUSIONS

OTG applied for 1 week had no clinically meaningful effect on recent memory or other cognitive functions in healthy, older adults.

CLINICAL TRIAL REGISTRATION

Registered as NCT00752141 at www.clinicaltrials.gov.

Application drying time for oxybutynin chloride topical gel

This study determined the median drying time for oxybutynin chloride topical gel (OTG) approved for treatment of overactive bladder was 3.1 minutes, Most participants reported positive perceptions of OTG attributes.

Thrombocytosis and venous thromboembolism in cancer patients with chemotherapy induced anemia may be related to ESA induced iron restricted erythropoiesis and reversed by administration of IV iron

ESA therapy can increase hemoglobin, decrease blood transfusions, and improve quality of life in patients with chemotherapy induced anemia (CIA). Despite its benefits, ESA therapy increases the risk of venous thromboembolism (VTE) in cancer patients by 50% and can also cause iron restricted erythropoiesis in CIA patients, which may augment the tendency to develop VTE. We postulated that thrombocytosis, a risk factor for VTE in cancer patients, in CIA patients on ESA therapy might be a result of ESA induced iron restricted erythropoiesis. We performed a retrospective analysis of 187 CIA patients who were randomized to receive weekly Epoetin and IV ferric gluconate, oral ferrous sulfate, or no iron for 8 weeks. Nineteen patients experienced 29 VTEs, and patients, whose platelets increased to ≥350,000 cells/uL were three times more likely to experience a VTE (OR 2.9, P = 0.036, logistic regression) with a four times greater incidence of VTE (IRR 4.4, P = 0.001, Poisson regression). Patients treated with IV iron were significantly less likely to develop platelets of ≥350,000 cells/uL (IRR 0.7, P = 0.013, Poisson regression) and had a decreased incidence of VTE. Our study suggests that ESA associated VTE in CIA patients may be, in part, related to the thrombocytosis of ESA induced iron restricted erythropoiesis and may be countered by IV iron.

Proteinuria induced by parenteral iron in chronic kidney disease--a comparative randomized controlled trial

BACKGROUND AND OBJECTIVES

Among patients with chronic kidney disease (CKD), differences in proteinuria are seen between intravenous iron preparations after a single dose exposure. This study examined differences in proteinuria between two intravenous iron preparations after multiple doses.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with iron-deficiency anemia and CKD, stratified by angiotensin converting enzyme inhibitor (ACEI)/angiotensin receptor-blocker (ARB) use, were randomized to iron sucrose or ferric gluconate. Each patient at 12 centers received 100 mg of study drug weekly for 5 weeks. Urine protein/urine creatinine ratio was measured before each dose and frequently thereafter for 3 hours.

RESULTS

Postbaseline data were available from 33 patients receiving iron sucrose and 29 patients receiving ferric gluconate. Although neither preparation of intravenous iron increased the predose level of proteinuria, the proteinuric response to intravenous iron was dependent on the type of iron and ACEI/ARB use. Without ACEIs/ARBs, ferric gluconate tended to cause less proteinuria with repeated iron administration; iron sucrose did not mitigate or aggravate proteinuria. Among patients receiving ACEIs/ARBs, in contrast to ferric gluconate, which produced only mild transient proteinuria, iron sucrose produced a consistent and persistent proteinuric response that was on average 78% greater.

CONCLUSIONS

Although multiple doses of either intravenous iron did not increase basal levels of proteinuria, postdose proteinuria was greater with iron sucrose than with ferric gluconate. These data suggest that nephrotoxicity of iron may depend on type of intravenous iron and on ACEI/ARB use. The long-term effects on kidney function need to be further evaluated.

Impact of transdermal oxybutynin on work productivity in patients with overactive bladder: results from the MATRIX study

BACKGROUND

Overactive bladder syndrome (OAB) is a common condition affecting a significant number of working adults, resulting in increased healthcare utilization, reduced quality of life and decreased work productivity. The MATRIX study was a large, prospective, community-based, observational US study aimed at evaluating the impact of oxybutynin transdermal system (OXY-TDS). In this paper, we report on productivity findings among working adults in MATRIX.

METHODS

This study enrolled 2878 adults (aged > or =18 years) with symptoms of OAB from 327 practice sites throughout the US. All subjects received OXY-TDS (3.9 mg/day up to 6 months). Baseline versus end-of-study productivity was measured using the Work Productivity Questionnaire (WPQ). The WPQ includes a subset of questions from the Work Limitations Questionnaire (WLQ) and consists of four scales: (i) physical; (ii) time management; (iii) mental; and (iv) output demands. Overall productivity was measured by the work productivity index score (WPQ Index; a summary score based on scales) and work productivity loss score (WPLS; a measure of reduced output compared with healthy workers). Psychometric performance of the WPQ instrument is also reported, since this study represents the first use of the tool.

RESULTS

Of the participants, 52% were of working age (18-65 years) and 38.6% were employed. A total of 1112 working adults participated in MATRIX and were included in this analysis. They had a mean age of 52.4 years; 92.2% were female and 80.9% were Caucasian. Subjects who reported that they were most affected by OAB were also most impaired at work. After OXY-TDS treatment, participants experienced significant improvements in mean scores for all four WPQ scales (p < or = 0.0002) and the mean WPQ Index decreased from 8.2 to 5.5 (p < 0.0001). In addition, the WPLS decreased from 7.7% to 5.2% (p < 0.0001), indicating improvement in work function with OXY-TDS treatment.

CONCLUSION

OAB contributes to decreased work productivity due to job interruptions as well as fatigue. OXY-TDS may result in productivity improvement when patients receive 3.9 mg/day via twice weekly patch application for up to 6 months.

Thrombosis with erythropoietic stimulating agents-does iron-deficient erythropoiesis play a role?

Thrombocytosis is common in iron deficiency and resolves following iron repletion. Increased platelet number, whether from iron deficiency or from other causes, may increase the risk of thrombovascular events. One mechanism thought to mediate iron deficiency-induced thrombocytosis is increased erythropoietin production. Similarly, erythropoietic stimulating agents (ESA) have long been known to increase platelet number and frequently lead to functional or absolute iron deficiency. This state of relative or absolute iron deficiency may be the mechanism whereby ESA increase the platelet count. If correct, co-administration of iron should prevent or diminish ESA-driven thrombocytosis. Data from the DRIVE trial in hemodialysis patients do, in fact, suggest that this is the case. Platelet counts in patients receiving IV iron decreased, while they remained unchanged in patients not given iron (mean change -29,000/microl vs. -0/microl; p = 0.017). Other supporting data have been observed in IV iron trials in oncology patients. The harm from higher hemoglobin targets and higher ESA doses may be mediated in part through induction of iron deficiency and thrombocytosis. The major anemia trials of ESAs have not reported platelet data, but should examine the relationship of platelet count, iron deficiency, IV iron administration, and cardiovascular events in greater detail.

Ferric gluconate reduces epoetin requirements in hemodialysis patients with elevated ferritin

The Dialysis Patients Response to IV Iron with Elevated Ferritin (DRIVE) study demonstrated the efficacy of intravenous ferric gluconate to improve hemoglobin levels in anemic hemodialysis patients who were receiving adequate epoetin doses and who had ferritin levels between 500 and 1200 ng/ml and transferrin saturation (TSAT) < or = 25%. The DRIVE-II study reported here was a 6-wk observational extension designed to investigate how ferric gluconate impacted epoetin dosage after DRIVE. During DRIVE-II, treating nephrologists and anemia managers adjusted doses of epoetin and intravenous iron as clinically indicated. By the end of observation, patients in the ferric gluconate group required significantly less epoetin than their DRIVE dose (mean change of -7527 +/- 18,021 IU/wk, P = 0.003), whereas the epoetin dose essentially did not change for patients in the control group (mean change of 649 +/- 19,987 IU/wk, P = 0.809). Mean hemoglobin, TSAT, and serum ferritin levels remained higher in the ferric gluconate group than in the control group (P = 0.062, P < 0.001, and P = 0.014, respectively). Over the entire 12-wk study period (DRIVE plus DRIVE-II), the control group experienced significantly more serious adverse events than the ferric gluconate group (incidence rate ratio = 1.73, P = 0.041). In conclusion, ferric gluconate maintains hemoglobin and allows lower epoetin doses in anemic hemodialysis patients with low TSAT and ferritin levels up to 1200 ng/ml.

Effects of oxybutynin transdermal system on health-related quality of life and safety in men with overactive bladder and prostate conditions

AIMS

Overactive bladder (OAB) is common in men and may exist concomitantly with benign prostatic hyperplasia (BPH) and obstruction. We present a subanalysis of results from men with OAB in a 6-month, open-label study of treatment with the oxybutynin transdermal system (OXY-TDS). Broad entry criteria were incorporated to yield a clinically representative population.

METHODS

All participants received OXY-TDS 3.9 mg/day. Effectiveness was assessed by changes in scores on validated questionnaires, which included the single-item Patient Perception of Bladder Condition (PPBC), the King's Health Questionnaire (KHQ) and the Beck Depression Inventory-II (BDI-II).

RESULTS

The proportion of men (n=369; mean age=69.6 years) who reported that their bladder condition caused moderate, severe or many severe problems (PPBC>or=4) improved from 77.3% at baseline to 38.1-53.6% in subsequent months. Mean KHQ scores decreased significantly (p<or=0.0196) from baseline to study end in eight of 10 domains, indicating improved health-related quality of life. The proportion of men with BDI-II score>12 (associated with a diagnosis of depression) decreased from 23.9% to 17.9% (p=0.0055). Men with a history of 'prostate problems' or use of 'BPH medication' (32.2%) had KHQ domain changes that were similar (p>or=0.1016) to those of other men. Most men (76.2%) reported no treatment-related adverse events; two men (0.5%) experienced symptoms of mild urinary retention, but neither required catheterisation.

CONCLUSIONS

Oxybutynin transdermal system treatment of men with OAB was effective and well tolerated, regardless of history of prostate condition.

Single-dosage pharmacokinetics of sodium ferric gluconate complex in iron-deficient pediatric hemodialysis patients

BACKGROUND AND OBJECTIVES

The clinical use of sodium ferric gluconate complex in iron-deficient pediatric patients receiving hemodialysis was recently approved. This study was designed to describe the pharmacokinetic parameters of the medication.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Iron-deficient pediatric (< or = 15 yr) hemodialysis patients were randomly assigned to two doses (1.5 and 3.0 mg/kg) of sodium ferric gluconate complex. Blood samples taken during a 1-h infusion and at multiple intervals during 48 h were analyzed for total iron, transferrin-bound iron, and sodium ferric gluconate complex-bound iron.

RESULTS

Forty-nine patients (mean age 12.3 +/- 2.5 yr) participated in the study. Mean serum iron concentrations rapidly increased in a dosage-dependent manner. A rapid rise in total serum iron was followed by a slower, less prominent rise in transferrin-bound iron. This was qualitatively confirmed by visualization of the transferrin bands from polyacrylamide gel electrophoresis. Single-dose pharmacokinetics of sodium ferric gluconate complex-bound iron was described using noncompartmental analytical methods. Mean values for the 1.5 mg/Kg dose were as follows: t(1/2) 2.0 +/- 0.7 h, Cmax 1287 mcg/dl, Tmax 1.1 +/- 0.23 h, Cl 0.69 +/- 0.50 L/h, Vd 1.6 +/- 0.6 L, AUC(0-infinity). 9499 +/- 4089 mcg x hr/dl.

CONCLUSIONS

The infusion of sodium ferric gluconate complex to pediatric patients who receive hemodialysis appears to result in a delayed transfer of iron to transferrin, likely after an initial movement through the reticuloendothelial system. Differences noted between the pediatric and adult pharmacokinetic data may result from the unique aspects of the study populations and the respective study designs.

Oxybutynin transdermal system improves the quality of life in adults with overactive bladder: a multicentre, community-based, randomized study

OBJECTIVE

To assess health-related quality-of-life (HRQoL) and safety with the oxybutynin transdermal system (OXY-TDS) (Oxytrol), Watson Pharma, Corona, CA, USA) in the Multicentre Assessment of Transdermal Therapy in Overactive Bladder With Oxybutynin (MATRIX) study, as HRQoL measurements are increasingly important in evaluating pharmacotherapy for overactive bladder (OAB).

PATIENTS AND METHODS

This randomized, open-label, community-based study enrolled 2878 participants aged >/=18 years who had been given a diagnosis of OAB. The 327 study sites were representative of various practice types. All participants were treated with OXY-TDS 3.9 mg/day for </=6 months. HRQoL was assessed using the King's Health Questionnaire (KHQ); the primary endpoint was the change in KHQ scores from baseline to study end.

RESULTS

Most enrolees (2052/2625; 78.2%) had moderate to severe OAB at baseline (Patient Perception of Bladder Condition score >/= 4 on a scale of 1-6), and most (1632/2859; 57.1%) had been given previous drug treatment for OAB. Of 2592 with evaluable baseline KHQ scores, 92.2% reported urgency and 88.2% reported urge urinary incontinence. The most impaired domains at baseline were Incontinence Impact (69.3), Symptom Severity (55.9), and Sleep/Energy (54.2). There were clinically meaningful and statistically significant improvements in nine of 10 domains at the study end; the greatest improvements were in Incontinence Impact (-13.5), Symptom Severity (-12.4), and Role Limitations (-13.3). The treatment was well tolerated, with low incidences of drug-related anticholinergic adverse effects such as dry mouth (75; 2.6%), constipation (44; 1.5%), and dizziness (21; 0.7%). There were drug-related application-site reactions, including pruritus, erythema, dermatitis and irritation, in 14.0% of participants.

CONCLUSIONS

OXY-TDS treatment was well tolerated in this diverse, community-based population, and resulted in clinically significant improvements in HRQoL, regardless of baseline characteristics.

Intravenous ferric gluconate significantly improves response to epoetin alfa versus oral iron or no iron in anemic patients with cancer receiving chemotherapy

PURPOSE

To evaluate the safety and efficacy of intravenous (IV) sodium ferric gluconate complex (FG), oral ferrous sulfate, or no iron to increase hemoglobin (Hb) in anemic cancer patients receiving chemotherapy and epoetin alfa.

PATIENTS AND METHODS

In this open-label, multicenter trial, 187 patients with chemotherapy-related anemia (Hb <11 g/dl; serum ferritin > or =100 ng/ml or transferrin saturation > or =15%) scheduled to receive chemotherapy and epoetin alfa (40,000 U subcutaneously weekly) were randomized to 8 weeks of 125 mg of IV FG weekly, 325 mg of oral ferrous sulfate three times daily, or no iron. The primary outcome was a change in Hb from baseline to endpoint, first whole-blood or red blood cell transfusion, or study withdrawal.

RESULTS

One hundred twenty-nine patients were evaluable for efficacy (FG, n = 41; oral iron, n = 44; no iron, n = 44). Mean increase in Hb was 2.4 g/dl (95% confidence interval [CI], 2.1-2.7) for FG (p = .0092 vs. oral iron; p = .0044 vs. no iron), 1.6 g/dl (95% CI, 1.1-2.1) for oral iron (p =.7695 vs. no iron), and 1.5 g/dl (95% CI, 1.1-1.9) for no iron. Hb response (increase > or =2 g/dl) was 73% for FG (p = .0099 vs. oral iron; p = .0029 vs. no iron), 46% for oral iron (p = .6687 vs. no iron), and 41% for no iron. FG was well tolerated.

CONCLUSION

For cancer patients with chemotherapy-related anemia receiving epoetin alfa, FG produces a significantly greater increase in Hb and Hb response compared with oral iron or no iron, supporting more aggressive treatment with IV iron supplementation for these patients.

Ferric gluconate is highly efficacious in anemic hemodialysis patients with high serum ferritin and low transferrin saturation: results of the Dialysis Patients' Response to IV Iron with Elevated Ferritin (DRIVE) Study

Few data exist to guide treatment of anemic hemodialysis patients with high ferritin and low transferrin saturation (TSAT). The Dialysis Patients' Response to IV Iron with Elevated Ferritin (DRIVE) trial was designed to evaluate the efficacy of intravenous ferric gluconate in such patients. Inclusion criteria were hemoglobin <or=11 g/dl, ferritin 500 to 1200 ng/ml, TSAT <or=25%, and epoetin dosage >or=225 IU/kg per wk or >or=22,500 IU/wk. Patients with known infections or recent significant blood loss were excluded. Participants (n=134) were randomly assigned to no iron (control) or to ferric gluconate 125 mg intravenously with eight consecutive hemodialysis sessions (intravenous iron). At randomization, epoetin was increased 25% in both groups; further dosage changes were prohibited. At 6 wk, hemoglobin increased significantly more (P=0.028) in the intravenous iron group (1.6 +/- 1.3 g/dl) than in the control group (1.1 +/- 1.4 g/dl). Hemoglobin response occurred faster (P=0.035) and more patients responded after intravenous iron than in the control group (P=0.041). Ferritin <or=800 or >800 ng/ml had no relationship to the magnitude or likelihood of responsiveness to intravenous iron relative to the control group. Similarly, the superiority of intravenous iron compared with no iron was similar whether baseline TSAT was above or below the study median of 19%. Ferritin decreased in control subjects (-174 +/- 225 ng/ml) and increased after intravenous iron (173 +/- 272 ng/ml; P<0.001). Intravenous iron resulted in a greater increase in TSAT than in control subjects (7.5 +/- 7.4 versus 1.8 +/- 5.2%; P<0.001). Reticulocyte hemoglobin content fell only in control subjects, suggesting worsening iron deficiency. Administration of ferric gluconate (125 mg for eight treatments) is superior to no iron therapy in anemic dialysis patients receiving adequate epoetin dosages and have a ferritin 500 to 1200 ng/ml and TSAT <or=25%.

The impact of the overactive bladder syndrome on sexual function: a preliminary report from the Multicenter Assessment of Transdermal Therapy in Overactive Bladder with Oxybutynin trial

OBJECTIVE

The objective of the study was to determine the impact of overactive bladder on sexual function from a preliminary analysis of the Multicenter Assessment of Transdermal Therapy in Overactive Bladder with Oxybutynin study.

STUDY DESIGN

The Multicenter Assessment of Transdermal Therapy in Overactive Bladder with Oxybutynin study was an open-label, prospective trial of 2878 subjects with overactive bladder, treated with transdermal oxybutynin for 6 months or less. The impact of overactive bladder on sexual function before and after treatment was assessed via item responses from the King's Health Questionnaire and Beck Depression Inventory-II (kappa-test).

RESULTS

At baseline, 586 (23.1%) reported that overactive bladder had an impact on their sex life. Coital incontinence in 569 (22.8%) decreased after treatment to 438 (19.3%). Effects of overactive bladder on subjects' sex lives improved in 19.1% (worsened in 11.2%), and the effect on relationships with partners improved in 19.6% (worsened in 11.9%). Reduced interest in sex, reported by 52.1% at baseline, improved significantly. (all P < .0001).

CONCLUSION

Overactive bladder negatively affects sexual function. Treatment with transdermal oxybutynin improved sexual function and marital relationships.

The nephrologist as a primary care provider for the hemodialysis patient

The role of nephrologists as de facto primary care providers (PCP) for dialysis patients is of increasing interest. We sought to determine the proportion of patients who rely on nephrologists for primary care and to identify demographic variables associated with this primary care responsibility. We reviewed the charts of 158 patients receiving hemodialysis at a suburban, freestanding, teaching hospital affiliated outpatient unit from December 1999 through January 2001. In addition, each patient was interviewed and completed a survey. Non-nephrologists were considered to be a patient's PCP if there was chart, survey or interview evidence of such a relationship. Of the 158 patients, only 56 patients had a PCP. The nephrologist thus was the de facto PCP in 65% of hemodialysis patients, a responsibility that was 3.3-fold more likely for patients not enrolled in a health maintenance organization (HMO) or managed care organization (MCO). In the non-HMO/MCO group, patients with a PCP had been on dialysis for less time than those without a PCP [2.7 vs. 4.6 years (P=0.0006)]. Only 32% of patients on dialysis <1 year had nephrologists as de facto PCP vs. 71% of those on dialysis more than 1 year (P=0.0002). This association between time on dialysis and de facto use of nephrologists as PCP was not accounted for by the shorter time on dialysis of HMO/MCO enrollees. The extent to which the nephrologist fulfills the often unsought role as PCP needs further investigation.

Single-dose pharmacokinetics of sodium ferric gluconate complex in iron-deficient subjects

STUDY OBJECTIVES

To determine the single-dose pharmacokinetics of intravenous sodium ferric gluconate complex in sucrose injection (SFGC) in iron-deficient human volunteers, and to assess iron transport.

DESIGN

Open-label, randomized study.

SETTING

Clinical research facility.

SUBJECTS

Fourteen iron-deficient men and women.

INTERVENTIONS

Subjects were randomized to receive a single intravenous dose of either SFGC 62.5 mg administered over 30 minutes or SFGC 125 mg over 60 minutes. Five days later, the same subjects were rerandomized to receive a second intravenous dose of SFGC, either 62.5 mg administered over 4 minutes or 125 mg over 7 minutes.

MEASUREMENTS AND MAIN RESULTS

Blood samples were collected at predefined times before, during, and up to 72 hours after the infusion to determine the single-dose pharmacokinetics of SFGC. Assays were performed for both total iron and transferrin-bound iron, from which drug-bound iron could be calculated. Urine was collected over 24 hours before dosing and for 24 hours after the start of infusion to determine the renal elimination of iron. Clearance of SFGC from serum was rapid and far exceeded rates reported for iron dextran. Pharmacokinetic parameters were unaffected by dose or infusion rate. Serum iron derived from SFGC did not exceed the binding capacity of transferrin. Serum iron from SFGC became rapidly available (< 24 hrs) as transferrin-bound iron, but only after passage through another compartment, presumably the reticuloendothelial system (RES). At least 80% of the administered iron was transported to bone marrow within 24 hours after infusion.

CONCLUSIONS

Iron derived from SFGC appears to be rapidly transferred to a bioavailable iron compartment as transferrin-bound iron after digestion in the RES. At the doses administered in this study, liberation of potentially toxic, free iron was not detectable.

Iron therapy in the pediatric hemodialysis population

Iron therapy maintains iron stores and optimizes the response to recombinant human erythropoietin (r-HuEPO) in patients with end-stage renal failure. Information is limited, however, regarding the preferential route of iron administration in pediatric patients receiving hemodialysis. Therefore, we prospectively randomized 35 iron-replete patients (aged >1 to <20 years) to receive up to 16 weeks of maintenance i.v. ( n=17) or daily oral ( n=18) iron. Eligible patients had received hemodialysis for >2 months, had a baseline transferrin saturation [TSAT] >20%, and were receiving maintenance r-HuEPO. Treatment arms were evenly distributed with respect to baseline demographic and clinical characteristics, with no statistically significant differences in baseline hemoglobin (Hb), hematocrit (Hct), reticulocyte Hb content (CHr), serum ferritin (SF), TSAT, or r-HuEPO dose. In the 35 patients, i.v. iron dextran and not oral iron was associated with a significant increase (138.5 to 259.1 ng/ml, P=0.003) in SF. A comparison of the change in SF between the i.v. iron group and the oral iron group was also significant ( P=0.001). Whereas only i.v. iron was associated with a significant decrease in the dose of r-HuEPO (234.0 to 157.6 U/kg per week, P=0.046) and an increase of the CHr (29.2 to 30.1 pg, P=0.049), these changes were not significantly different from those experienced by patients in the oral iron group. In both groups, the Hct remained stable and in neither group was there a significant change in the TSAT. In summary, although both oral and i.v. iron maintained patients in an iron-replete state in this short-term study, only i.v. therapy allowed for a significant improvement in iron stores.

Sodium ferric gluconate complex in haemodialysis patients: a prospective evaluation of long-term safety

BACKGROUND

A previous single dose placebo-controlled double-blinded trial showed an extremely low (0.4%) intolerance rate of sodium ferric gluconate complex (SFGC) in SFGC-naive haemodialysis patients. No large prospective trials have assessed the safety of SFGC during repeated exposure in the outpatient haemodialysis setting.

METHODS

Chronic haemodialysis patients completing the single-dose trial of SFGC were eligible to participate in this prospective, multicentre, open-label, long-term evaluation of SFGC, designed to record adverse events occurring up to 72 h post-dose. Patients received as many as 20 ampules (1250 mg total) of SFGC at an investigator-determined dose and rate over a 9 month evaluation period.

RESULTS

Among 1412 enrolled patients at 54 centres, 1321 received 13,151 infusions of SFGC. Most doses (94.8%) were < or =125 mg and the majority were given over 10 min. Infusion rates ranged from <5 to 125 mg/min. There were no life-threatening events. Fifty-one patients (3.9%) experienced an adverse event, possibly related to SFGC. Of these, one experienced a serious event (hypotension). Five patients (0.4%) experienced an event that precluded SFGC readministration: pruritus (three), vasodilatation (one) and loss of taste (one). Among 372 patients (28.2%) receiving angiotensin-converting enzyme inhibitor (ACEI) therapy, adverse events were neither more common nor more severe than in the other patients.

CONCLUSIONS

Repeated doses of SFGC are very well tolerated in haemodialysis patients. No life-threatening events were observed in over 13,000 doses administered. Administration of SFGC to patients using ACEI is safe and does not increase the incidence or severity of adverse events to SFGC.

Herbs, menopause, and dialysis

Women with chronic kidney disease (CKD) are at increased risk for menstrual disorders, early menopause, and osteoporosis, and rarely discuss gynecologic and reproductive issues with their nephrologist. Various complementary and alternative medicine (CAM) products are of interest to women with end-stage renal disease (ESRD) who have these disorders. However, very little is known about the specifics of using herbal medicines in patients on chronic dialysis, resulting in numerous problems when patients and providers try to ascertain the safety and efficacy of these products. This article reviews evidence regarding the safety and efficacy of black cohosh, ginseng, chastetree, dong quai, evening primrose oil, soy products, and the so-called natural hormones. Pharmacologic parameters important to evaluating the quality of botanical products are discussed, along with recommendations and information resources.

Herbs and supplements in dialysis patients: panacea or poison?

The safety of herbal remedies and supplement use is of particular concern in patients with renal disease, and reliable information is not always easy to find. Predialysis patients may be drawn to complementary and alternative medicine (CAM) because they believe it can help prevent the progression of their renal disease. The purpose of this series of articles on alternative medicine for nephrologists is to address concerns and issues specific to CAM use in dialysis patients and to provide a guide to reliable sources of information. This introductory article emphasizes safety issues with a focus primarily on herbal medicine. Lack of regulation means that patients may not actually be taking what they think they are. Independent laboratory analyses have shown a lack of stated label ingredients and many instances of supplements and traditional remedies being contaminated with pesticides, poisonous plants, heavy metals, or conventional drugs. While certain supplements are always unsafe (carcinogenic, hepatotoxic, glandular extracts), others are specifically contraindicated in renal disease. Supplement use may be especially hazardous in renal disease because of unpredictable pharmacokinetics, drug interactions, negative effects on kidney function, nephrotoxicity, hemodynamic alterations, unpredictable effects on blood pressure or blood glucose, or potentiation of electrolyte abnormalities. There are no data on potential dialyzability of either active compounds, or their potentially active or toxic metabolites. Many supplements contain metal ions and other minerals. Transplant recipients are also at risk from potential unpredictable effects on immune function. Recommendations and information resources are listed.

Measuring total body water in peritoneal dialysis patients using an ethanol dilution technique

Measuring total body water in peritoneal dialysis patients using an ethanol dilution technique.

BACKGROUND

The accuracy with which total body water (TBW) is estimated is a direct determinant of the reliability of Kt/V urea measurements in peritoneal dialysis (PD) patients. Ethanol dilution has been previously shown to be a reliable measure of TBW. Advances in breath alcohol technology make this a feasible clinical tool.

METHODS

We gave 19 fasting chronic PD patients 0.3 g/kg of ethanol (EtOH) orally on two separate occasions. Breath alcohol concentrations (BrACs), determined by dual-beam infrared analysis, were recorded at baseline and periodically thereafter until BrACs were less than 0.01%. The TBW was then determined by standard pharmacokinetic techniques.

RESULTS

TBW measurements were reproducible, with a mean between-run difference of -0.004 liter/kg (95% limits of agreement -0.040 to 0. 032 by Bland-Altman). The Watson equations tended to underestimate TBW, with a mean difference (EtOH - Watson) of +3.0 liters (SD 4.0 liters, P = 0.004) and a mean absolute difference of 4.1 liters (SD 2.7 liters, range -4.4 to 9.5 liters). Kt/V was calculated from dialysate and urine collection, using V as determined from TBW estimates from EtOH and Watson. The mean Kt/V(EtOH) was 2.31 (SD 0. 50) compared with 2.46 (SD 0.52) using Watson. The mean absolute difference between the two Kt/V estimates was 0.26 (SD 0.20, range -0.87 to 0.57), with Kt/V overestimated by Watson in 14 patients. EtOH was well tolerated, and the procedure was completed in about four hours.

CONCLUSIONS

Measuring V by the BrAC technique does not require blood sampling, is reliable, and is reproducible. It is a potentially useful method for a periodic determination of volume that may allow for more accurate Kt/V measurement in PD patients.

Pharmacokinetics of intraperitoneal fluconazole during continuous cycling peritoneal dialysis

OBJECTIVE

To investigate the pharmacokinetic characteristics of intraperitoneal fluconazole in patients undergoing continuous cycling peritoneal dialysis (CCPD).

DESIGN

Prospective, nonrandomized, single-dose, open-label study.

PARTICIPANTS

Five noninfected volunteer CCPD patients.

INTERVENTIONS

Patients received a single dose of intraperitoneal fluconazole 200 mg during their long daytime dwell. Blood samples were collected before and 1, 3, 6, 12 (end of first dwell), 24 (after overnight cycling), 48, 72, 96, and 120 hours after dosing. Used dialysate was collected throughout the study. Unless the patient was anuric, urine was collected for the first 48 hours.

MAIN OUTCOME MEASURE

Fluconazole concentrations were assayed by gas-liquid chromatography. Pharmacokinetic parameters were calculated using standard noncompartmental techniques.

RESULTS

The bioavailability of intraperitoneal fluconazole was 96% +/- 2% over a 12-hour dwell, absorption half-life was 2.5 +/- 1.2 hours, serum elimination half-life was 71.65 +/- 12.76 hours, and volume of distribution was 0.66 +/- 0.13 L/kg. Peritoneal clearance was 5.96 +/- 0.93 mL/min and proportional to total dialysate volume. Renal clearance was proportional to renal creatinine clearance.

CONCLUSIONS

Current treatment guidelines for fungal peritonitis suggest fluconazole 200 mg intraperitoneally every 24 hours. Our data suggest that this dose, administered every 48 hours, is more than sufficient to maintain serum and peritoneal concentrations above the minimum inhibitory concentration for most Candida spp. Other factors, such as residual renal function and dialysis prescription, may also need to be considered.

Pulse dose oral calcitriol therapy for renal osteodystrophy: literature review and practice recommendations

Oral pulse dosing of calcitriol has been proposed as an alternative to intravenous administration in the treatment of renal osteodystrophy. A review of the literature suggests it can provide a safe and effective method that is especially convenient for peritoneal dialysis patients with mild to moderate bone disease. However, its use should be accompanied by careful monitoring and control of serum calcium, phosphorus, and parathyroid hormone levels. Some practical suggestions are provided.