Dataset Information

Choice of High-Dose Intravenous Iron Preparation Determines Hypophosphatemia Risk.

ABSTRACT:

Background

Ferric carboxymaltose (FCM) and iron isomaltoside 1000 (IIM) are increasingly used because they allow correction of severe iron deficiency in a single infusion. A transient decrease in serum phosphate concentrations is a frequent side effect of FCM.

Aim

To characterize this adverse event and search for its predictors in a gastroenterology clinic patient cohort.

Methods

Electronic medical records of patients attending the University Hospital of Innsbruck were searched for the keywords ferric carboxymaltose or iron isomaltoside. Eighty-one patients with documented administration of FCM or IIM with plasma phosphate concentrations before and after treatment were included.

Results

The prevalence of hypophosphatemia (<0.8 mmol/L) increased from 11% to 32.1% after treatment with i.v. iron. The hypophosphatemia risk was greater after FCM (45.5%) compared with IIM (4%). Severe hypophosphatemia (<0.6 mmol/L) occurred exclusively after FCM (32.7%). The odds for hypophosphatemia after i.v. iron treatment were independently determined by baseline phosphate and the choice of i.v. iron preparation (FCM vs. IIM-OR = 20.8; 95% CI, 2.6-166; p = 0.004). The median time with hypophosphatemia was 41 days, but prolonged hypophosphatemia of ≥ 2 months was documented in 13 of 17 patients in whom follow-up was available. A significant increase in the phosphaturic hormone intact FGF-23 in hypophosphatemic patients shows that this adverse event is caused by FCM-induced hormone dysregulation.

Conclusion

Treatment with FCM is associated with a high risk of developing severe and prolonged hypophosphatemia and should therefore be monitored. Hypophosphatemia risk appears to be substantially lower with IIM.

SUBMITTER: Schaefer B

PROVIDER: S-EPMC5131956 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundHigh-dose intravenous iron is an effective treatment option for iron deficiency (ID) or ID anaemia (IDA) in inflammatory bowel disease (IBD). However, treatment with ferric carboxymaltose (FCM) has been associated with the development of hypophosphatemia.AimTo investigate mechanisms behind the development of hypophosphatemia after intravenous iron treatment, and disclose symptoms and clinical manifestations related to hypophosphatemia short-term.MethodsA prospective observational study of adult IBD patients with ID or IDA was conducted between February 1, 2017 and July 1, 2018 at two separate university hospitals in the southeast region of Norway. Patients received one dose of 1000 mg of either FCM or ferric derisomaltose (FDI) and were followed for an observation period of at least 7 wk. Blood and urine samples were collected for relevant analyses at baseline, week 2 and at week 6. Clinical symptoms were assessed at the same timepoints using a respiratory function test, a visual analogue scale, and a health-related quality of life questionnaire.ResultsA total of 106 patients was available for analysis in this study. The FCM treatment group consisted of 52 patients and hypophosphatemia was present in 72.5% of the patients at week 2, and in 21.6% at week 6. In comparison, the FDI treatment group consisted of 54 patients and 11.3% of the patients had hypophosphatemia at week 2, and 3.7% at week 6. The difference in incidence was highly significant at both week 2 and 6 (P < 0.001 and P < 0.013, respectively). We observed a significantly higher mean concentration of intact fibroblast growth factor 23 (P < 0.001), a significant rise in mean urine fractional excretion of phosphate (P = 0.004), a significant decrease of 1,25-dihydroxyvitamin D (P < 0.001) and of ionised calcium levels (P < 0.012) in the FCM-treated patients compared with patients who received FDI. No clinical symptoms could with certainty be related to hypophosphatemia, since neither the respiratory function test, SF-36 (36-item short form health survey) or the visual analogue scale scores resulted in significant differences between patients who developed hypophosphatemia or not.ConclusionFibroblast growth factor 23 has a key role in FCM induced hypophosphatemia, probably by inducing loss of phosphate in the urine. Short-term clinical impact of hypophosphatemia was not demonstrated.

Project description:Hypophosphatemia can complicate intravenous iron therapy, but no head-to-head trials compared the effects of newer intravenous iron formulations on risks and mediators of hypophosphatemia. In a randomized, double-blinded, controlled trial of adults with iron deficiency anemia from February 2016 to January 2017, we compared rates of hypophosphatemia in response to a single FDA-approved course of ferric carboxymaltose (n = 1,000) or ferumoxytol (n = 997). To investigate pathophysiological mediators of intravenous iron-induced hypophosphatemia, we nested within the parent trial a physiological substudy (ferric carboxymaltose, n = 98; ferumoxytol, n = 87) in which we measured fibroblast growth factor 23 (FGF23), calcitriol, and parathyroid hormone (PTH) at baseline and 1, 2, and 5 weeks later. The incidence of hypophosphatemia was significantly higher in the ferric carboxymaltose versus the ferumoxytol group (<2.0 mg/dl, 50.8% vs. 0.9%; <1.3 mg/dl, 10.0% vs. 0.0%; P < 0.001), and hypophosphatemia persisted through the end of the 5-week study period in 29.1% of ferric carboxymaltose-treated patients versus none of the ferumoxytol-treated patients (P < 0.001). Ferric carboxymaltose, but not ferumoxytol, increased circulating concentrations of biologically active FGF23 (mean within-patient percentage change from baseline to week 2 peak: +302.8 ± 326.2% vs. +10.1 ± 61.0%; P < 0.001), which was significantly associated with contemporaneous hypophosphatemia, renal phosphate wasting, and decreased serum calcitriol and calcium, and increased PTH concentrations. Ferric carboxymaltose rapidly increases biologically active FGF23 in patients with iron deficiency anemia. Paralleling hereditary and other acquired syndromes of hypophosphatemic rickets/osteomalacia, ferric carboxymaltose-induced FGF23 elevation triggers a pathophysiological cascade of renal phosphate wasting, calcitriol deficiency, and secondary hyperparathyroidism that frequently culminates in hypophosphatemia. ClinicalTrials.gov, NCT02694978FUNDING. AMAG Pharmaceuticals, Inc.Role of the funding source: This study was supported by AMAG Pharmaceuticals, Inc. The academic investigators designed the clinical trial, performed the analyses, and authored the manuscript with input from the coauthors from AMAG Pharmaceuticals, Inc.

Project description:BackgroundIn patients with iron deficiency anemia, ferric carboxymaltose (FCM) and ferric derisomaltose (FDI) allow high-dose iron repletion. While FCM is reported to induce hypophosphatemia, the frequency of hypophosphatemia after an equivalent dosage of FDI had not been assessed prospectively.MethodsIn the prospective, single-center, double-blind HOMe aFers study, 26 women with iron deficiency anemia (hemoglobin < 12 g/dL plus either plasma ferritin ≤ 100 ng/mL or a plasma ferritin ≤ 300 ng/mL and transferrin saturation (TSAT) ≤ 30%) were randomized to a single intravenous infusion of 20 mg/kg body weight (up to a maximum of 1000 mg) FCM or FDI. The primary endpoint was the incidence of hypophosphatemia (plasma phosphorus levels < 2.0 mg/dL at day 1, day 7 ± 2, and/or day 35 ± 2 after the infusion). In order to investigate potential skeletal and cardiovascular implications, we assessed changes in other components of mineral and bone metabolism, left ventricular function, and arrhythmias.ResultsHypophosphatemia occurred more frequently in women treated with FCM (9 out of 12 [75%]) than in those treated with FDI (1 out of 13 [8%]; p = 0.001). Within 24 h after iron supplementation, women in the FCM group had significant higher plasma intact FGF23 (p < 0.001) and lower plasma 1.25-dihydroxyvitamin D (p < 0.001). As an indicator of urinary phosphorus losses, urinary fractional phosphorus excretion was higher in the FCM group (p = 0.021 at day 7 ± 2 after iron supplementation). We did not observe differences in skeletal and cardiovascular markers, potentially because of the limited number of participants.ConclusionsWhile both FCM and FDI provide efficient iron repletion in participants with iron deficiency anemia, FCM induced hypophosphatemia more often than FDI.Trial registrationClinical Trials.gov NCT02905539. Registered on 8 September 2016. 2015-004808-36 (EudraCT Number) U1111-1176-4563 (WHO Universal Trial Number) DRKS00010766 (Deutsches Register Klinischer Studien).

Project description:BACKGROUND:Intravenous (IV) iron supplementation is a standard maintenance treatment for hemodialysis (HD) patients, but the optimum dosing regimen is unknown. METHODS:PIVOTAL (Proactive IV irOn Therapy in hemodiALysis patients) is a multicenter, open-label, blinded endpoint, randomized controlled (PROBE) trial. Incident HD adults with a serum ferritin < 400 µg/L and transferrin saturation (TSAT) levels < 30% receiving erythropoiesis-stimulating agents (ESA) were eligible. Enrolled patients were randomized to a proactive, high-dose IV iron arm (iron sucrose 400 mg/month unless ferritin > 700 µg/L and/or TSAT ?40%) or a reactive, low-dose IV iron arm (iron sucrose administered if ferritin <200 µg/L or TSAT < 20%). We hypothesized that proactive, high-dose IV iron would be noninferior to reactive, low-dose IV iron for the primary outcome of first occurrence of nonfatal myocardial infarction (MI), nonfatal stroke, hospitalization for heart failure or death from any cause. If noninferiority is confirmed with a noninferiority limit of 1.25 for the hazard ratio of the proactive strategy relative to the reactive strategy, a test for superiority will be carried out. Secondary outcomes include infection-related endpoints, ESA dose requirements, and quality-of-life measures. As an event-driven trial, the study will continue until at least 631 primary outcome events have accrued, but the expected duration of follow-up is 2-4 years. RESULTS:Of the 2,589 patients screened across 50 UK sites, 2,141 (83%) were randomized. At baseline, 65.3% were male, the median age was 65 years, and 79% were white. According to eligibility criteria, all patients were on ESA at screening. Prior stroke and MI were present in 8 and 9% of the cohort, respectively, and 44% of patients had diabetes at baseline. Baseline data for the randomized cohort were generally concordant with recent data from the UK Renal Registry. CONCLUSIONS:PIVOTAL will provide important information about the optimum dosing of IV iron in HD patients representative of usual clinical practice. TRIAL REGISTRATION:EudraCT number: 2013-002267-25.

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