Preoperative Anemia and Perioperative Outcomes in Children: Prevalence, Risk Factors, and Associations in an Australian Cohort

AIMS: Preoperative anemia is a potentially modifiable risk factor in children undergoing surgery, but contemporary data describing its prevalence and associated outcomes in high-income settings are limited. We aimed to determine the prevalence of anemia in a pediatric major-surgery surgical cohort, identify associated demographic and clinical factors, and examine relationships with perioperative outcomes. METHODS: We conducted a retrospective observational study of children undergoing major surgery at an Australian tertiary children's hospital. Patients with a hemoglobin measurement within 3 months prior to surgery were included. Anemia was defined according to the World Health Organization 2024 thresholds. Demographic variables, comorbidities, surgical characteristics, transfusion, and postoperative outcomes were extracted. Logistic regression was used to evaluate independent associations between preoperative anemia, red cell transfusion, and postoperative infection. RESULTS: Of 786 eligible patients, 582 (74%) were included. Anemia was present in 123 children (21.1%, 95% CI 18.0-24.6). Anemia was more common in females, higher ASA classification, emergency surgery, and those with chronic comorbidities. In multivariable analyses, anemia was independently associated with red cell transfusion (aOR 2.77, 95% CI 1.74-4.41), and with postoperative infection (aOR 1.89, 95% CI 1.15-3.09). Other postoperative outcomes were not significantly associated with preoperative anemia. Anemia remained common in elective surgical patients, a group in whom preoperative screening and optimization are feasible. CONCLUSION: Preoperative anemia affects one in five children undergoing major surgery in this Australian cohort and is independently associated with red cell transfusion and postoperative infection. These findings support further evaluation of strategies to identify and manage preoperative anemia in pediatric surgical patients. The observed prevalence and outcome associations in this cohort should be interpreted in the context of missing preoperative hemoglobin data, which may bias estimates toward higher risk patients.