Increasing Body Mass Index is Associated With Worse Perioperative Outcomes and Higher Costs in Adult Spinal Deformity Surgery

STUDY DESIGN: Retrospective review. OBJECTIVE: To investigate associations of obesity with outcomes and costs of adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA: Increasing body mass index (BMI) is a risk factor for complications after nondeformity spine surgery, but its effect on ASD surgery is unknown. METHODS: We reviewed records of 244 ASD patients who underwent spinal arthrodesis of ≥5 levels from 2010 to 2014 and categorized them by World Health Organization BMI groups: BMI 2 days), prolonged total length of hospital stay (LOS) (>1 week), and high episode-of-care costs (>80, 000). RESULTS: Preoperative characteristics were similar among groups, except sex, preoperative hemoglobin concentration, and performance/type of osteotomy (all, P = 0. 01). On univariate analysis, the groups differed in rates of prolonged ICU stay (P < 0. 001), prolonged total LOS (P = 0. 016), and high episode-of-care costs (P = 0. 013). Inpatient complication rates were similar among groups (P = 0. 218). On multivariate analysis, compared with nonobese patients, class I obese patients had greater odds of prolonged ICU stay (odds ratio OR = 2. 24, 95% confidence interval CI: 1. 06, 4. 71). Class II/III obese patients also had greater odds of prolonged total LOS (OR = 2. 21, 95% CI: 1. 03, 4. 71), and high episode-of-care costs (OR = 2. 91, 95% CI: 1. 31, 6. 50). CONCLUSION: In ASD surgery, BMI ≥35 is associated with significantly worse perioperative outcomes and higher costs compared with those of nonobese patients. LEVEL OF EVIDENCE: 3.