Anemia Correction Before Colorectal Surgery Yields No Postoperative Gains

A recent prospective subanalysis of an international open-labeled trial indicated that early detection and prevention of preoperative anemia is possible before colorectal surgery. However, preoperative iron administration cannot completely prevent postoperative complications, including colorectal anastomotic leakage (CAL).

“Despite evidence indicating that preoperative anemia is a significant predictor of CAL and an important target for optimization, it is not consistently detected and corrected during the preoperative phase,” wrote Anne de Wit, MD, department of surgery, Amsterdam University Medical Centers, and colleagues. “The aim of this study was to obtain detailed information on the impact of early detection and correction of preoperative anemia on perioperative and postoperative outcomes in patients undergoing colorectal surgery.”1

The study was designed as a subanalysis of the DoubleCheck study, which was conducted between September 2021 and December 2023. The primary outcome of the DoubleCheck study was the occurrence of intraoperative risk factors before anastomosis creation, with secondary outcomes including CAL and mortality. Results ultimately indicated that optimizing modifiable risk factors – such as anemia, glucose levels, and administration of antibiotics – can reduce CAL in colorectal surgery.2

This subanalysis of the DoubleCheck study was conducted simultaneously and comprised the same 899 patients. de Wit and colleagues included participants regardless of whether the indication for resection was benign or malignant; the only exclusion criteria were an age <18 years and emergency surgery.1

The study's primary outcome was the incidence of preoperative anemia following implementation of active screening. Anemia was defined as blood hemoglobin level <7.5 mmol/L for female patients and <8.0 mmol/L for male patients, combined with a ferritin <30.0 μg/L or the specified hemoglobin levels with ferritin between 30.0 μg/L and 100.0 μg/L, transferrin saturation <15.0-20.0%, and C-reactive protein >5.0 mg/L. Anemia was classified as severe (<6.0 mmol/L), mild (6.0-7.0 mol/L), and minor (>7.0 mmol/L).1

Secondary outcomes included the effects of preoperative screening and anemia correction on CAL, as well as postoperative outcomes and mortality; both outcomes were collected 30 and 90 days postoperatively.1

After diagnosis of anemia, 77.4% of patients were treated; 87.9% received intravenous iron, while 12.1% received oral supplements in the weeks before surgery. Hemoglobin in this group decreased in 4.2% of patients, remained unchanged in 45.8%, and increased in 50.0%. Perioperative anemia was observed in 32.3% of patients; severe preoperative anemia was exhibited in 6.2%, mild in 37.6%, and minor in 56.2%.1

de Wit and colleagues only observed CAL in 6.1% of the patients, which was also not significantly associated with correction of preoperative anemia (P =.0607) or changes in hemoglobin levels after iron treatment (P =.736). There was no significant relationship between CAL severity and preoperative correction or hemoglobin level changes (P =.318, P =.192). Additionally, incidence and severity of postoperative complications did not differ or vary between the treated and untreated groups (P =.494; P =.235).1

The team noted these results demonstrated a reduction in incidence and severity of perioperative anemia following the introduction of preoperative treatment. This is consistent with knowledge concerning iron treatment and its effect on postoperative anemia. Importantly, however, this did not lead to a significant alteration in postoperative outcomes.1

“Preoperative anemia may be more indicative of overall poor physiological fitness rather than an isolated factor,” wrote de Wit and colleagues. “Implementation of early and consistent preoperative anemia detection and correction will enhance the quality of care for patients undergoing colorectal surgery.”1

References

1. de Wit A, Bootsma BT, Huisman DE, Kazemier G, Daams F; Taskforce Anastomotic Leakage. Early detection and correction of preoperative anemia in patients undergoing colorectal surgery-a prospective study. Tech Coloproctol. 2025;29(1):92. Published 2025 Apr 5. doi:10.1007/s10151-025-03131-5

2. de Wit A, Bootsma BT, Huisman DE, et al. Risk Factor Targeted Perioperative Care Reduces Anastomotic Leakage after Colorectal Surgery: The DoubleCheck study. Ann Surg. Published online July 11, 2024. doi:10.1097/SLA.0000000000006442