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. 2015 Feb;61(2):159.

Iron deficiency anemia in the elderly

Adrienne J Lindblad 1, Candra Cotton 2, G Michael Allan 3
PMCID: PMC4325864  PMID: 25676647

Clinical question

In elderly patients with iron deficiency anemia (IDA), what is the appropriate dose of iron?

Bottom line

In elderly patients with IDA, low doses of iron lead to similar increases in hemoglobin as are achieved with higher doses but cause considerably fewer adverse events in most patients. Options for dosing include half of a 300-mg ferrous gluconate tablet per day or 2.5 mL of ferrous sulfate syrup a day. Clinicians should work up the cause of anemia, as appropriate.

Evidence

One RCT addresses this question.1

  • In total, 90 patients with anemia (mean age 85 years, 59% women) were randomized to receive 15 mg, 50 mg, or 150 mg of elemental iron per day.
    • -At 2 months, there were no differences among the groups in hemoglobin or serum ferritin levels.
      • —Hemoglobin increased by 14 g/L in all 3 groups.
    • -Adverse events were significantly more common at higher doses (P < .05).

  • Number needed to harm (NNH) for 150 mg versus 15 mg: abdominal cramps, NNH = 2; nausea or vomiting, NNH = 2; constipation, NNH = 5; and dropout due to adverse events, NNH = 5.

Context

  • Iron deficiency anemia is common in the elderly.2
    • -More than 10% have IDA at age 65 and older, and more than 20% have IDA at age 85 and older.

  • In older patients, IDA requires workup for potential causes, including gastrointestinal malignancy.3

  • In the very elderly (age 85 and older), IDA carries an increased risk of mortality (hazard ratio 1.41 [95% CI 1.13 to 1.76]) in addition to the condition causing anemia.4

  • Iron is commercially available in 300-mg tablets. For dose conversion:
    • -300 mg of ferrous fumarate equals 100 mg of elemental iron5;
    • -300 mg of ferrous sulfate equals 60 mg of elemental iron5; and
    • -300 mg of ferrous gluconate equals 35 mg of elemental iron.5
  • For dosing to 15 mg of elemental iron per day, consider: -half of a 300-mg ferrous gluconate tablet (or 1 every other day); or
    • -doses of 2.5 mL of ferrous sulfate syrup per day or 1 dropper (1 mL) of ferrous sulfate drops per day.

Implementation

The price of different oral iron formulations varies; they range from about $3 to $30 per month, with polysaccharide-iron complexes and liquid formulations being the most expensive. Taking iron on an empty stomach improves absorption.6 Vitamin C might increase the absorption of dietary iron by about 10%.7 Conversely, calcium might decrease iron absorption; however, the effects on clinical outcomes are unknown.8 If both are required, it might help to take iron and calcium hours apart.

Tools for Practice

Tools for Practice articles in Canadian Family Physician (CFP) are adapted from articles published on the Alberta College of Family Physicians (ACFP) website, summarizing medical evidence with a focus on topical issues and practice-modifying information. The ACFP summaries and the series in CFP are coordinated by Dr G. Michael Allan, and the summaries are co-authored by at least 1 practising family physician and are peer reviewed. Feedback is welcome and can be sent to toolsforpractice@cfpc.ca. Archived articles are available on the ACFP website: www.acfp.ca.

Footnotes

The opinions expressed in Tools for Practice articles are those of the authors and do not necessarily mirror the perspective and policy of the Alberta College of Family Physicians.

References

  • 1.Rimon E, Kagansky N, Kagansky M, Mechnick L, Mashiah T, Namir M, et al. Are we giving too much iron? Low-dose iron therapy is effective in octogenarians. Am J Med. 2005;118(10):1142–7. doi: 10.1016/j.amjmed.2005.01.065. [DOI] [PubMed] [Google Scholar]
  • 2.Guralnik JM, Eisenstaedt RS, Ferrucci L, Klein HG, Woodman RC. Prevalence of anemia in persons 65 years and older in the United States: evidence for a high rate of unexplained anemia. Blood. 2004;104(8):2263–8. doi: 10.1182/blood-2004-05-1812. Epub 2004 Jul 6. [DOI] [PubMed] [Google Scholar]
  • 3.Ioannou GN, Rockey DC, Bryson CL, Weiss NS. Iron deficiency and gastrointestinal malignancy: a population-based cohort study. Am J Med. 2002;113(4):276–80. doi: 10.1016/s0002-9343(02)01214-7. [DOI] [PubMed] [Google Scholar]
  • 4.Den Elzen WP, Willems JM, Westendorp RG, de Craen AJ, Assendelft WJ, Gussekloo J. Effect of anemia and comorbidity on functional status and mortality in old age: results from the Leiden 85-plus study. CMAJ. 2009;181(3–4):151–7. doi: 10.1503/cmaj.090040. Epub 2009 Jul 27. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 5.Wiebe A, Ricci P, Geall B, Gross L, Dumont Z. Iron management. Chronic kidney disease. Iron deficiency anemia. In: Jensen B, Regier LD, editors. RxFiles drug comparison charts. 10th ed. Saskatoon, SK: Saskatoon Health Region; 2014. pp. 164–5. [Google Scholar]
  • 6.Milman N, Bergholt T, Eriksen L, Byg KE, Graudal N, Pedersen P, et al. Iron prophylaxis during pregnancy—how much iron is needed? A randomized dose-response study of 20–80 mg ferrous iron daily in pregnant women. Acta Obstet Gynecol Scand. 2005;84(3):238–47. doi: 10.1111/j.0001-6349.2005.00610.x. [DOI] [PubMed] [Google Scholar]
  • 7.Hunt JR, Mullen LM, Lykken GI, Gallagher SK, Nielsen FH. Ascorbic acid: effect on ongoing iron absorption and status in iron-depleted young women. Am J Clin Nutr. 1990;51(4):649–55. doi: 10.1093/ajcn/51.4.649. [DOI] [PubMed] [Google Scholar]
  • 8.Cook JD, Dassenko SA, Whittaker P. Calcium supplementation: effect on iron absorption. Am J Clin Nutr. 1991;53(1):106–11. doi: 10.1093/ajcn/53.1.106. [DOI] [PubMed] [Google Scholar]

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