Decrease in hemoglobin following colorectal surgery: A cohort study with focus on iron deficiency

Background: Occurrence of anemia following colorectal cancer surgery is common and has been associated with decreased overall survival. We examine the perioperative hemoglobin change following minimally invasive colorectal cancer surgery. The aim is to assess if an association between decreasing hemoglobin and the existence of preoperative iron deficiency exists. Methods: Registry based single center cohort study. Surgical colorectal cancer patients (2013–2019) being non-anemic prior to surgery and who underwent intended laparoscopic and curatively planned surgery were included. Hemoglobin change from pre-surgery to discharge was compared between patients with and without preoperative iron deficiency. Analysis was done using multivariate linear regression analysis. Changes in hydration status and inflammation were also accessed and compared to the change in hemoglobin. Results: Out of a consecutive cohort of 1228 patients, 353 fulfilled the eligibility criteria and were available for analysis. The mean change in hemoglobin-concentration for all patients was -2.02 g/dl (SD +- 1.28) and an intraindividual decrease occurred in 95 % of the patients. Preoperative iron deficiency was not associated with the decrease in hemoglobin (correlation =-0.13, 95 % CI -0.43 – 0.18, p = 0.41). There was a statistically significant association between decreasing albumin levels and decreasing hemoglobin levels. Conclusions: Following minimally invasive laparoscopic surgery, 95 % of non-anemic surgical colorectal cancer patients experienced a decreasing hemoglobin level. The median hemoglobin decrease was 2 g/dl during hospitalization. Preoperative iron deficiency was not associated with the decrease in hemoglobin levels.