Costs
Ferritin determination may be cost-effective depending on its cost, the cost of iron therapy, the prevalence of iron-deficiency anemia (which is dependent on the criteria for defining anemia), and the nonfinancial burden of unnecessary iron therapy. The costs of sparing women unnecessary iron therapy on the basis of these variables are detailed in the [Table]. Serum ferritin level determination cost $30 at the laboratory we used for our study. Other methods of determining iron deficiency (such as iron and total iron-binding capacity levels, which cost $35) were not evaluated, since the evidence did not suggest that these values were accurate or well known in pregnant women. Using numbers derived from our study, checking the ferritin levels of 100 pregnant women with anemia would cost $3000 and spare 37 to 46 women from taking iron, at a cost of $37.24 to $73.56 to prevent 1 woman from taking an unnecessary course of iron therapy.
Caretakers prescribing iron therapy are familiar with its adverse effects and relatively low tolerability. In a dose-finding study12 of 110 pregnant women randomized to 1 of 3 doses of ferrous sulfate daily, 32.4% of those taking 60 mg of elemental iron (equivalent to 325 mg of ferrous sulfate) and 40.5% of those taking 120 mg of elemental iron (equivalent to common twice a day dosing) had side effects. Dropout rates matched the side effect rates (32.4% and 38.8%, respectively). Thus, for every 5 women treated with iron, 2 will develop side effects and stop taking it.
The cost-effectiveness of ferritin determination is highly dependent on and inversely related to the prevalence of iron-deficiency anemia in the patient population. As seen in the Table, if the prevalence of iron-deficiency anemia is sufficiently low, ferritin determination may be very cost-effective.
Clinicians should consider the local costs of ferrous sulfate, ferritin determination, and the prevalence of iron-deficiency anemia in their patient population in the evaluation of the use of ferritin determination instead of empiric iron therapy. Alternately, clinicians may present some of the issues and uncertainties to their patients for combined decision making.
Conclusions
In our population of prenatal patients with anemia, only 54% had an iron deficiency. Diagnostic and therapeutic approaches to screening for anemia in pregnancy should be reconsidered and further evaluated to avoid unnecessary iron therapy.
Acknowledgments
We would like to acknowledge Siobhan Ulrich, Jan Balmer, Sue Gibson, and Tracy Chappel for their efforts in implementing the practice protocol and keeping track of patient records.