Practice guidelines for Iron deficiency anemia (IDA) suggest taking ferrous iron in divided doses. Recent studies suggest that split daily dosing may increase serum hepcidin which reduces iron bioavailability. Adherence to oral iron supplementation (OIS) can also be a barrier to treatment. In practice iron dosing varies significantly with unclear evidence of benefit from a particular dosing regimen.


This is a retrospective study evaluating outcomes of different schedules of OIS in 146 patients with IDA (Hb <12.2 and/or ferritin of < 30 ng/mL) treated between June 2017-June 2018. Patients with multifactorial anemia were excluded. Descriptive statistics and Chi-square were used for analysis.


The mean age was 66.8 ± 1.3; women constituted 70% of the cohort (M/F 44/102). Mean Hb was 11.59 ± 0.12; Median ferritin was 22 ng/ml (IQR 10-63). Four different schedules of OIS evaluated were every other day (QOD) 60% (88/146), daily (QD)15% (22/146), twice daily (BID) 12%(18/146) and three times a day (TID) 12% (18/146). After one month of OIS a mean increase in Hb was (0.44 mg/dl + 0.04). GI toxicity occurred in 10.2% (15/146), therapy discontinuation in 4.8% (7/146) and IV iron was required in 9.6 % (14/146) of all cases. Among patients without GI toxicity 65% (85/131) were on QOD vs other schedules (X² 11.7 p=0.008), 63% (87/139) were compliant on QOD (X² 9.05 p=0.029). Salvage IV iron was not required in 64% (84/132) of QOD patients (X² 22.7 p=<0.001). One month post therapy, patients on QOD schedule had ≥1 g/dl improvement in 38% (10/26) (X² 9.18 p= 0.027) and increase of >0.5g/dl in 68% (69/102) of cases (X² 9.63 p= 0.022).


Alternate day iron dosing may optimize iron absorption and is possibly a better tolerated regimen. Larger prospective studies need to confirm these findings


No relevant conflicts of interest to declare.

Author notes


Asterisk with author names denotes non-ASH members.