Introduction Iron deficiency anaemia (IDA) is the most common micronutrient deficiency worldwide, and is a major cause of referral to secondary care. Orally administered iron may inadequately control symptoms of IDA, particularly in those with underlying gastrointestinal (GI) conditions that impair iron absorption or cause bleeding. Inadequate treatment of IDA may increase the risk of hospital treatment and associated costs. In this study, the potential relationship of oral and intravenously administered iron with hospitalisation is examined in a retrospective cohort.

Method Patients in England aged over 18 years with a GI condition and IDA between 1^stJan 2010–31^stOct 2013 were drawn from the HTI-CPRD dataset. Patients who attended hospital and received a prescription for IV or oral iron were included, and followed for hospitalisation within 30 days after the initial visit. The population is described in terms of demographic characteristics, comorbid conditions and common concomitant medications. Logistic regression was used to examine the association between hospitalisation within 30 days and the form of iron treatment. The duration of hospital stays was also examined.

Results There were 4024 qualifying hospitalisations. Of 3143 patients receiving oral iron, 81% were hospitalised within 30 days. Of 881 patients receiving IV iron, 34% were hospitalised within 30 days. Hospital stays were longer in the oral iron group (min 0, max 120.2, median 5.4 days) compared with the IV group (0; 43.1; 1.2). The unadjusted odds ratio for a hospitalisation within 30 days for those prescribed IV compared to oral was 0.12, indicating substantially higher odds of hospitalisation in the oral group. The final model adjusted for confounders included age, gender, history of anaemia, elective and non-elective visit, menorrhagia, pregnancy, comcomitant treatment and history of reduced kidney function. The adjusted odds ratio (OR) was 0.49 (95% CI 0.41–0.59) demonstrating an attenuated but statistically significant reduced odds of hospitalisation in the IV iron group.

Conclusion This study shows substantially reduced odds of hospitalisation amongst IDA patients when prescribed IV rather than oral iron. It is striking that the chance of hospitalisation after entry into the cohort was greater than even for those treated with oral iron, and less than even for those treated with IV iron. The magnitude of the apparent effect on morbidity suggests it is potentially clinically important and warrants further research.

Disclosure of interest None Declared.