Risk Factors for Perioperative Blood Transfusions in Adult Spinal Deformity Surgery

Objective: Adult spinal deformity (ASD) surgery is associated with a high rate of perioperative blood transfusions, and it is important to understand the risk factors for perioperative blood transfusions to implement strategies to reduce transfusions. The aim of this study was to identify independent risk factors of perioperative blood transfusions in patients undergoing surgery for ASD. Methods: A retrospective cohort study was performed using the American College of Surgeons National Surgical Quality Improvement Program database from 2010 to 2014. Adult patients undergoing surgery for ASD were separated into 2 cohorts based on whether they received a perioperative blood transfusion. Univariate and multivariate regression models were used to identify risk factors for blood transfusion. Results: In our cohort of 5805 patients, 27.1% received a blood transfusion. Multivariate regression analysis showed that patient-specific risk factors were age 65 years or older (odds ratio [OR], 1.74; 95% confidence interval [CI], 1.49–2.03; P < 0.001), American Society of Anesthesiologists classification of 3 or greater (OR, 1.18; 95% CI, 1.01–1.37; P = 0.033), cardiac comorbidity (OR, 1.21; 95% CI, 1.03–1.41; P = 0.018) and bleeding disorder (OR, 2.01; 95% CI, 1.10–3.66; P = 0.023). Surgery-specific risk factors were a posterior approach (OR, 4.25; 95% CI, 3.46–5.22; P < 0.001), pelvic fixation (OR, 1.73; 95% CI, 1.36–2.20; P < 0.001), and osteotomy (OR, 2.08; 95% CI, 1.71–2.51; P < 0.001). Longer operative time was also a risk factor with a duration-dependent effect on the odds of blood transfusion. Conclusions: Recognition of patient- and surgery-specific risk factors for perioperative blood transfusion is important to identify patients who are at high risk and to implement strategies to minimize intraoperative blood loss and decrease healthcare costs.