Preoperative anemia increases risk of postoperative delirium in elderly, suggests research

A new study published in the Korean Journal of Anesthesiology showed that preoperative anemia may be associated with a higher risk of postoperative delirium (POD) in elderly patients undergoing non-cardiac surgery. The study reported a 7.2% incidence of POD in anemic patients, compared to just 2.6% in non-anemic patients.

Although a direct causal relationship was not established, the findings highlight a potential association that warrants further investigation. POD is a serious complication affecting up to 5% of general surgery patients, with incidence varying based on surgery type and patient demographics. It is also linked to longer hospital and ICU stays, increased morbidity, and higher mortality risk.

Surgical patients frequently suffer from anemia, which has been linked to negative consequences like decreased executive function, longer hospital stays, and higher death rates. Postoperative delirium and preoperative anemia may or may not be related. Thus, this retrospective study looked into the connection between POD and preoperative anemia in older patients having non-cardiac surgery. Ah Ran Oh and colleagues postulated that a higher incidence of delirium following non-cardiac surgery would be linked to preoperative anemia.

A total of 62,600 individuals over 60 who had non-cardiac surgery between January 2011 and June 2019 were examined retrospectively by researchers. Based on the existence of preoperative anemia, which is defined as hemoglobin < 13 g/L for males and < 12 g/dl for women, the patients were split into two groups. A threshold of 11 g/dl was used to further classify anemia into mild or moderate-to-severe anemia. POD within seven days following surgery was the main result. One- and three-year mortality following surgery were among the secondary outcomes.

Within 7 days following surgery, the total incidence of POD was 3.9% (2,447 / 62,600). Preoperative anemia was substantially linked to a higher incidence of POD following IPTW. Additionally, the more severe the anemia, the higher the chance of POD. For both one- and three-year mortality, this correlation was comparable.

Overall, after non-cardiac surgery, preoperative anemia was linked to an increased incidence of POD in older patients. The more severe the anemia, the stronger this relationship became. To show if reducing preoperative anemia may successfully lower POD, further prospective research should be done.

Reference:

Oh, A. R., Park, J., Kim, C. S., Lee, S. M., & Yoo, S. Y. (2025). Association between preoperative anemia and postoperative delirium in elderly patients undergoing non-cardiac surgery: a retrospective observational study. Korean Journal of Anesthesiology. https://doi.org/10.4097/kja.24701