Joint effect of pre-operative anemia and perioperative blood transfusion on outcomes of colon-cancer patients undergoing colectomy

Background Both pre-operative anemia and perioperative (intra- and/or post-operative) blood transfusion have been reported to increase post-operative complications in patients with colon cancer undergoing colectomy. However, their joint effect has not been investigated. The purpose of this study was to evaluate the joint effect of pre-operative anemia and perioperative blood transfusion on the post-operative outcome of colon-cancer patients after colectomy. Methods We identified patients from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database 2006–2016 who underwent colectomy for colon cancer. Multivariate logistic regression analysis was employed to assess the independent and joint effects of anemia and blood transfusion on patient outcomes. Results A total of 35,863 patients—18,936 (52.8%) with left-side colon cancer (LCC) and 16,927 (47.2%) with right-side colon cancer (RCC)—were identified. RCC patients were more likely to have mild anemia (62.7%) and severe anemia (2.9%) than LCC patients (40.2% mild anemia and 1.4% severe anemia). A total of 2,661 (7.4%) of all patients (1,079 [5.7%] with LCC and 1,582 [9.3%] with RCC) received a perioperative blood transfusion. Overall, the occurrence rates of complications were comparable between LCC and RCC patients (odds ratio [OR] = 1.01; 95% confidence interval [CI] = 0.95–1.07; P = 0.750). There were significant joint effects of anemia and transfusion on complications and the 30-day death rate (P for interaction: 0.010). Patients without anemia who received a transfusion had a higher risk of any complications (LCC, OR = 3.51; 95% CI = 2.55–4.85; P < 0.001; RCC, OR = 3.74; 95% CI = 2.50–5.59; P < 0.001), minor complications (LCC, OR = 2.54; 95% CI = 1.63–3.97; P < 0.001; RCC, OR = 2.27; 95% CI = 1.24–4.15; P = 0.008), and major complications (LCC, OR = 5.31; 95% CI = 3.68–7.64; P < 0.001; RCC, OR = 5.64; 95% CI = 3.61–8.79; P < 0.001), and had an increased 30-day death rate (LCC, OR = 6.97; 95% CI = 3.07–15.80; P < 0.001; RCC, OR = 4.91; 95% CI = 1.88–12.85; P = 0.001) than patients without anemia who did not receive a transfusion. Conclusions Pre-operative anemia and perioperative transfusion are associated with an increased risk of post-operative complications and increased death rate in colon-cancer patients undergoing colectomy.