Preoperative and postoperative anemia in major elective surgery: insights from a retrospective cohort in a Brazilian University Hospital

Background Anemia is a common and critical condition in the perioperative management of patients undergoing major elective surgeries, posing significant risks to postoperative recovery. This study aimed to evaluate the prevalence of preoperative and postoperative anemia in surgical patients from a university hospital in northeastern Brazil. Methods This retrospective study included 508 patients aged 18-years or older who underwent major elective surgeries between October 2021 and October 2022. Anemia was defined according to World Health Organization criteria (hemoglobin < 13 g.dL -1 for men and < 12 g.dL -1 for women). Data were extracted from medical records and included preoperative and postoperative hemoglobin levels, surgical types, and transfusion requirements. Results Preoperative anemia was observed in 59.6% of 508 patients analyzed, with a mean Hb level of 11.66 (±/2.75) g.dL -1 and 11.13 (±2.08) g.dL -1 for women and men, respectively. In the postoperative period, the anemia rate increased to 94.6%, with a mean Hb level of 9.36 (±1.55) g.dL -1 and 9.49 (±1.36) g.dL -1 for women and men, respectively. The transfusion rate was 27% in the total sample. Patients with preoperative anemia were 4.6-times more likely to require intraoperative transfusion compared to non-anemic patients (OR = 4.58; 95% CI: 2.78–7.52; p < 0.001). Higher preoperative hemoglobin levels were identified as protective against transfusion (OR = 0.65; 95% CI: 0.59–0.72; p < 0.001). Conclusions Preoperative anemia is a highly prevalent and modifiable risk factor associated with increased transfusion requirements and adverse perioperative outcomes. The study highlights the importance of implementing patient blood management protocols in surgical practice.