Does Intravenous Iron Therapy Decrease Serum Phosphorous Levels?

Does Intravenous Iron Therapy Decrease Serum Phosphorous and Vitamin D Levels in Patients With and Without Chronic Renal Failure?

Intravenous iron therapy is common and effective, with few side effects. Two formulations are used, venofer or iron sucrose and ferrlecit, or ferric gluconate.

The association between intravenous iron use and decrease in serum phosphorus and vitamin D levels, with increased fractional excretion of phosphorus, has been observed with older iron preparations, such as saccharated ferric oxide. However, hypophosphatemia and osteomalacia have been reported with iron carboxymaltose, a newer iron formulation. There is no information in the literature about phosphorus and vitamin D levels after treatment with venofer or ferrlecit. We intend to check phosphorus and vitamin D serum levels in our patients prior to and after treatment with these iron formulations.

Study Overview

• Status: Completed
• Conditions: Chronic Renal Failure
• Intervention / Treatment: Other: non interventional

Detailed Description

Intravenous iron replacement has become quite common in cases where oral iron therapy is insufficient or poorly tolerated. Various intravenous iron preparations have been used in patients on dialysis and with chronic kidney disease for many years, however, these patients have severely reduced glomerular filtration rate and are generally hyperphosphatemic.

Although generally safe, certain iron preparations have been associated with severe phosphorus and calcitriol deficiency, caused by elevation in serum levels of fgf23, a phosphaturic humoral factor derived from osteocytes. Fractional excretion of phosphorus is indeed raised in these patients. In some cases phosphorus deficiency, or high fgf23 levels, are so severe that osteomalacia can result . This phenomenon has been observed with saccharated ferric oxide , a preparation commonly used in Japan, and in iron polymaltose . It has also been observed with iron carboxymaltose , a newer iron preparation, now available in Israel. These reports propose that iron causes elevated fgf23 levels, which in turn decreases phosphorus absorption and inhibits 1α-hydroxylase activity. Patients with deficient vitamin D have greater tendency to develop hypophosphatemia.

This phenomenon of phosphorus deficiency has not been documented in the commonly used preparations of iron sucrose (venofer) and ferric gluconate (ferrlecit). These non-dextran iron preparations have a very low rate of allergic reactions and adverse events. They are used in various cases of iron deficiency anemia with normal renal function, such as patients with Inflammatory bowel disease , diabetics or in people who cannot tolerate oral iron therapy. Moreover, certain oral iron preparations are under investigation at present for their role as phosphorus binders.

The purpose of this study is to measure phosphorus, parathyroid hormone and vitamin D levels in patients prior to and after intravenous iron therapy in patients with iron deficiency anemia with normal and reduced Glomerular Filtration Rate . We hypothesize that iron therapy with ferric gluconate and iron sucrose will induce hypophosphatemia and low levels of 1,25 hydroxide Vit D. We will try to ascertain whether the hypophosphatemia is clinically significant or merely a low laboratory value, and whether patients with vitamin 25 hydroxide -D deficiency have a greater propensity to develop it.

• Study Type: Observational
• Enrollment (Actual): 53

Contacts and Locations

Study Locations

• Israel
  • Afula, Israel
    • Haemek Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

in a period of one year we will try to recruit approximately 100 men and women over the age of 18, who have iron deficiency anemia and have been prescribed intravenous iron treatment at the ambulatory treatment unit.

Description

Inclusion Criteria:

• Age 18 and over
• Have an indication for intravenous iron treatment
• Estimated Creatinine clearance at least 30ml/min (patients with lower Estimated Creatinine clearance may not be able to excrete phosphorus)
• Have signed informed consent.

Exclusion Criteria:

• Pregnancy
• Estimated creatinine clearance below 30 ml/min.

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Decrease in Serum Levels of Phosphorus in Patients After Treatment With Intravenous Iron.	serum phosphorus levels were measure at baseline, and after intravenous iron administration	3 month

Collaborators and Investigators

• Sponsor: Frieda Wolf

Study record dates

Study Major Dates

• Study Start: January 1, 2015
• Primary Completion (ACTUAL): January 1, 2016
• Study Completion (ACTUAL): January 1, 2016

Study Registration Dates

• First Submitted: April 14, 2015
• First Submitted That Met QC Criteria: April 16, 2015
• First Posted (ESTIMATE): April 17, 2015

Study Record Updates

• Last Update Posted (ACTUAL): August 9, 2022
• Last Update Submitted That Met QC Criteria: August 8, 2022
• Last Verified: August 1, 2022

More Information

Terms related to this study

• Keywords: vitamin D; Iron Therapy; serum phosphates
• Additional Relevant MeSH Terms: Kidney Diseases; Urologic Diseases; Renal Insufficiency, Chronic; Kidney Failure, Chronic; Renal Insufficiency
• Other Study ID Numbers: EMC 59-14

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO