More than one-third of patients without anemia upon admission to Royal Perth Hospital in Australia developed anemia during hospital stay. In addition, patients with anemia had worse outcomes, according to a report published in Transfusion.

This retrospective cohort study included all patients admitted to Royal Perth Hospital between July 2010 and June 2015 with stays longer than 48 hours. Nadir hemoglobin value (Hb) was chosen as the measure for anemia, and the outcomes assessed were in-hospital mortality and hospital length of stay. Confounding factors, such as red blood cell (RBC) transfusion, were also taken into consideration.

In total, 80,765 admissions from 58,765 patients were assessed. The average age at time of admission was 58.3 ± 20.9 years, and 42.5% of patients were female. Of the 45,675 patients who had anemia during their hospital stay, 30,389 (66.5%) experienced mild anemia and 15,286 (33.5%) experienced moderate to severe anemia. Furthermore, 24,827 (54.4%) had anemia on admission and 17,208 (36.67%) did not have anemia on admission.

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During the study period, 1763 in-hospital deaths occurred. The adjusted odds of in-hospital mortality were 1.6 times higher (95% CI: 1.4-1.9, P =.001) in patients with mild anemia and 2.8 times higher (95% CI: 2.3-3.3, P <.001) in those with moderate to severe anemia than in patients without anemia on admission. Furthermore, patients who received RBC transfusion had 2.2 times higher adjusted odds of in-hospital mortality (95% CI: 1.9-2.6, P <.001).

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The average length of stay was 5.7 ± 2.1 days. Patients with mild anemia had 1.7 times longer stays (95% CI: 1.6-1.7, P <.001) and those with moderate to severe anemia had 3.0 times longer stays (95% CI 2.9-3.1, P <.001). Patients who received RBC transfusion had 2.8 times longer stays (95% CI 2.6-2.9, P<.001).

“Anemia identification, evaluation, and management for all hospitalized patients may need to become a new standard of care,” the researchers concluded.


1. Krishnasivam D, Trentino KM, Burrows S, et al. Anemia in hospitalized patients: an overlooked risk in medical care [published online October 1, 2019]. Transfusion. doi: 10.1111/trf.14877