The Effects of Blood Transfusion on Delirium Incidence.

Background: Both anemia and blood transfusion could be precipitating factors for delirium; hence in postoperative patients with anemia at high risk for delirium, it is controversial whether transfusion is the best option. The aim of this study is to investigate the association of anemia and delirium and the role of blood transfusion within the multicomponent prevention strategy of delirium.

Methods: We conducted a substudy of a multicenter randomized controlled trial. Four hundred fifteen patients aged 65 to 102 years old admitted for hip fracture surgery were enrolled. Delirium was assessed daily using criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition. Data on hemoglobin values and transfusion were collected from the electronic medical records.

Results: One hundred fifteen (32.5%) patients experienced delirium during hospitalization, 238 (57.5%) had a hemoglobin level ≤ 6.0 mmol/L (9.7 g/dL) at any time during hospitalization, and 140 (33.7%) received a blood transfusion. Anemia (a hemoglobin level ≤ 6.0 mmol/L [9.7 g/dL]) was associated with delirium (odds ratio, 1.81; 95% confidence interval, 1.15-2.86). Blood transfusion was a protective factor for delirium in patients with the lowest measured hemoglobin level ≤ 6.0 mmol/L (9.7 g/dL) (odds ratio, 0.26; 95% confidence interval, 0.10-0.70).

Conclusion: Low hemoglobin level is associated with delirium, and receiving a blood transfusion is associated with a lower delirium incidence. It would be interesting to investigate the effect of blood transfusion as part of the multicomponent treatment of delirium in patients with anemia.