Iron deficiency in Women of Childbearing Age with Self-reported Oral Iron Gastrointestinal Intolerance and Management with an oral Iron-Whey-Protein Formulation

Background Intolerance to oral iron is thought to result in poor adherence and persistence of nutritional deficit amongst women of childbearing age, however few studies have evaluated oral iron intolerance, iron deficiency and anaemia in this setting. Iron-whey protein microspheres (IWP) could help. Methods We documented self-reported oral iron gastrointestinal intolerance, ferritin and haemoglobin levels in a screening study of women of childbearing age. Following a washout period of 16 days, we randomised 59 of these women with iron deficiency, stratified according to the presence of anaemia, to three doses of IWP: (14mg daily, 25mg daily and 50mg daily). We excluded those with established gastrointestinal disease, potential allergy to whey protein and severe anaemia. The primary endpoint was persistence and adherence (>80% based on pill-counts). Secondary endpoints included changes in self-reported oral iron gastrointestinal intolerance, gastro-intestinal symptom rating scale (GSRS), serum iron, serum ferritin, transferrin saturation and haemoglobin levels. Results A total of 128 (62.7%) of the participants had low iron stores (ferritin < 30 µg/L), 65 (31.9%) had moderate to severe iron deficiency (ferritin <12 µg/L) and 33 (16.2%) had iron deficiency anaemia. Amongst 59 women who participated in the prospective study, 48 (81.4%) were classified as adherent/persistent with therapy using IWP compared to 12 (20.3%) taking the prior oral iron p<0.0001. These patients also showed significantly fewer reports of gastrointestinal intolerance with IWP (0.59 ± 0.91) and lower GSRS scores (6.2 ± 7.5) compared to the previous oral iron product (3.98 ± 2.22, and 15.6 ± 9.7 respectively, both P<0.0001). There were no differences in adherence, self-reported adverse GI effects and GSRS between the dose groups during the study. Serum iron levels increased across the whole cohort from 11.3 ± 7.4 μmol/L to 20.5± 11.0 μmol/L (P<0.0001), transferrin saturation levels increased from 18.4 ± 13.3 % to 33.6 ± 17.6 % (P<0.0001) and median ferritin levels overall increased from 8.00 [IQR 6.00;13.0] to 15.5 [IQR 9.00;24.2] µg/L at 12 weeks (P=0.0002). Haemoglobin levels increased from 11.36 g/dL (95%CI 10.95 to 11.77) to 12.40 g/dL (95%CI 12.03 to 12.76, P=0.0007) in patients with anaemia and were normalised in most patients taking 50mg IWP daily. Conclusions Low iron, iron deficiency and anaemia are common in women of childbearing age with a history of intolerance to oral iron. Patients with low iron (ferritin < 30 µg/L) and moderate to severe iron deficiency (ferritin <12 µg/L) have similar impairment of energy. IWP can improve self-reported oral iron adherence and tolerability as well as iron stores, haemoglobin and tiredness in these women.