93. Cost utility analysis of a combined approach for surgical correction of adult spinal deformity

Abstract

BACKGROUND CONTEXT With the increasing emphasis on value-based outcomes in health care, there has been an increased focus on the cost of surgical intervention in patients with adult spinal deformity (ASD). However, there is a paucity of literature on the economic impact of a surgeon's surgical approach for corrective ASD surgery. PURPOSE To investigate the cost-utility associated with surgical approach. STUDY DESIGN/SETTING Retrospective cohort study of a prospective multicenter ASD database. PATIENT SAMPLE This study included 208 ASD patients. OUTCOME MEASURES Oswestry Disability Index (ODI), SF-6D, cost per quality adjusted life years (QALY). METHODS ASD patients with no previous history of fusions, complete radiographic, and HRQL data at baseline and 2 years were included. Patients were propensity score matched for age, CCI, levels fused, frailty, SVA, PI-LL and osteotomies. Means comparison tests and ANOVA chi-squared analyses assessed differences in baseline demographic and clinical data between cohorts. Utility data were calculated using ODI converted to SF-6D using published conversion methods. QALYs utilized a 3% discount rate to account for residual decline to life expectancy (78.7 years). Costs were calculated using the PearlDiver database incorporating complications, comorbidities (CC), major complications, and comorbidities (MCC) were assessed according to CMS.gov manual definitions. Two-year reimbursement consisted of a standardized estimate using regression analysis of Medicare pay-scales for all services rendered within a 30-day window, including estimates regarding costs of postoperative complications, outpatient health care encounters, revisions and medical related readmissions. After accounting for CC, MCC, length of stay (LOS), revisions, and death, cost per QALY at 2 years and life expectancy were calculated for surgical approach. RESULTS A total of 208 PSM ASD patients were included (62.2yrs, 84% F, 26.9 kg/m2). Patients undergoing a combined approach had a longer LOS (6.55 vs 8.15), greater operative time, and experienced significantly greater blood loss (all p 0.05). Despite initial higher costs of a combined approach, the average cost of ASD surgery at 2 years follow-up for posterior-only approach was greater compared to a combined approach ($72,749 vs $65,073). Furthermore, the cost per QALY was higher for posterior-only patients at 2 years compared to patients undergoing a combined approach ($363,910 vs $333,981). If utility gained is sustained to life expectancy, the cost per QALY was $54,027 for posterior-only and $49,584 for combined. CONCLUSIONS In a matched cohort of adult spinal deformity patients, a combined approach trended toward a lower average cost of surgery at 2 years, lower cost per QALY, significantly lower rates of operative complications and revisions. Although improvement after surgical intervention was similar between the two approaches, cost per QALY of posterior-only approach was slightly greater primarily driven by increased operative complications and rates of revisions. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.