Preoperative anemia in older individuals undergoing major abdominal surgery is associated with early postoperative morbidity: a prospective observational study

Preoperative anemia is associated with poor postoperative outcomes. Older patients have limited physiologic reserves, which renders them vulnerable to the stress of major abdominal surgery. We aimed to determine if the severity of preoperative anemia is associated with early postoperative morbidity among older patients undergoing major abdominal surgery.

Ethics approval was obtained from SingHealth Centralized Institutional Review Board. This is a prospective observational study conducted in the preoperative anesthesia clinic of a tertiary Singapore hospital from 2017 to 2021. Patient demographic data, comorbidities, and intraoperative details were collected. Outcome measures included blood transfusions, complications according to the Postoperative Morbidity Survey, days alive and out of hospital (DaOH), length of hospital stay, and mortality.

A total of 469 patients were analyzed, 37.5% of whom had preoperative anemia (serum hemoglobin of < 13 g·dL⁻¹ in males and < 12 g·dL⁻¹ in females). Anemia was significantly associated with older age, a higher age-adjusted Comprehensive Complication Index score, a higher incidence of diabetes mellitus, and a higher proportion of patients with an American Society of Anesthesiologists Physical Status of III or IV. The severity of anemia was associated with the presence of early postoperative morbidity at day 5, increased blood transfusions, longer length of hospital stay, and fewer DaOH at 30 days and six months.

Anemia is significantly associated with poorer postoperative outcomes in the older population. The impact of anemia on postoperative outcomes could be further evaluated with quality of life indicators, patient-reported outcome measures, and health economic tools.