Preoperative Anemia and Iron Deficiency in Elective Gastrointestinal Cancer Surgery Patients.

Background and objectives: Preoperative anemia can impact postoperative outcomes, but its importance in gastrointestinal cancer patients, and significance of anemia etiology remains unclear. We aimed to characterize the frequency and impact of preoperative anemia, and iron-deficiency anemia (IDA), on perioperative outcomes.

Methods: We performed a retrospective cohort study of adult patients undergoing elective gastrointestinal cancer surgery. The primary outcome was the incidence of perioperative RBC transfusion. Secondary outcomes included 90-day postoperative major morbidity, ICU admission, and 90-day hospital readmission. Multivariable analyses were performed to assess the association between preoperative anemia and IDA and outcomes.

Results: Preoperative anemia was present in 55.5% of patients (n = 15 414), and 58.3% of anemic patients were iron deficient. Preoperative anemia was independently associated with increased risk of RBC transfusion (RR 2.88, 95% CI 2.60-3.20), and secondary outcomes. For every preoperative hemoglobin decrease of 1 g/dL, the adjusted risk of perioperative RBC transfusion increased by 40% (RR 1.39, 95% CI 1.37-1.42).

Conclusion: Preoperative anemia is prevalent, and an independent risk factor for adverse postoperative outcomes. Decreases in preoperative hemoglobin levels elevate the risk of transfusion and adverse outcomes, supporting further study to optimize management of treatable causes of preoperative anemia including IDA.