Effect of Preoperative Anemia on the Outcomes of Anterior Cervical Discectomy and Fusion

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Preoperative anemia has been associated with an increased need for blood transfusions and postoperative complications. The effects of anemia on the outcomes of anterior cervical discectomy and fusion (ACDF) have not been explored. The present study aimed to evaluate the association between preoperative anemia and 30-day complications following ACDF surgery. METHODS: Data from the American College of Surgeons National Surgical Quality Improvement Program (2005-2012) was used. Preoperative anemia was defined as hematocrit <39% for males and <36% for females. A bivariate analysis was performed on demographic and perioperative variables. Multivariable logistic regression models were employed, adjusting for patient variables, to identify independent risk factors for complications. RESULTS: A total of 3500 patients were included of which 444 (12.7%) were anemic patients. Multivariate analysis was used to quantify the predictive power of anemia on key postoperative outcomes, while controlling for the other statistically significant. Preoperative anemia was found to be a statistically significant predictor of any complication (odds ratio [OR] = 1.853; 95% confidence interval [CI] = 1.17-2.934; P = .0086), pulmonary complications (OR = 3.269; 95% CI = 1.745-6.126; P = .0002), intraoperative blood transfusion (OR = 4.364; 95% CI = 1.48-12.866; P = 0.0076), return to operating theatre (OR = 2.655; 95% CI = 1.539-4.582; P = .0005), and length of hospital stay more than 5 days (OR = 2.151; 95% CI = 1.499-3.085; P < .0001). CONCLUSION: Preoperative anemia appears to be a significant predictor of perioperative complications, reoperation, and extended length of hospital stay in patients undergoing elective ACDF. Future studies should explore outcomes of treatment of preoperative anemia prior to surgery to determine the optimal management strategy.