131. Reaching minimal clinically important difference (MCID) is not predictive of improved cost-per-QALY at two years in surgically treated adult spinal deformity patients (ASD)

Abstract

BACKGROUND CONTEXT Surgical management of ASD patients is complex and costly. Optimizing patient treatment requires an understanding of which patients clinically benefit most from intervention and the economic resources required to care for this patient population. PURPOSE To determine whether surgically treated adult spinal deformity patients who reach MCID threshold will have lower cost-per-QALY (Quality Adjusted Life Year) than patients not reaching MCID. STUDY DESIGN/SETTING Prospective, multicenter study. PATIENT SAMPLE ASD patients from a multicenter, prospective surgical database, with >4 level fusion and 2-year follow-up were included. OUTCOME MEASURES Cost-per-QALY and MCID. METHODS ASD patients from a multicenter, prospective surgical database, with >4 level fusion and 2-year follow-up were included. Index and total EOC cost were calculated using Medicare's inpatient prospective payment system (IPPS) for DRGs 453-460. All costs were adjusted for inflation to 2019 US dollar values. QALYs gained were calculated using baseline, 1-year, and 2-year SF-6D scores. A discount rate of 3% was assumed. Cost-per-QALY was determined by calculating total EOC per cumulative QALY at two years. Clinical effectiveness was determined by threshold improvement in MCID values: ODI (-15), SF-36 physical component (5.2), SRS-activity (0.375), SRS-pain (0.587), SRS-appearance (0.8), and SRS-mental (0.42). RESULTS DRG data for index and revision surgery was available for 250/402 patients meeting inclusion criteria. Mean age was 62.0+12.5 years, 77% were women, and 91% were Caucasian. Overall, the mean cost/QALY was $59,514.01 at two years. The mean+SD QALY gain at two years was 0.06+0.12 (p CONCLUSIONS The majority of surgically treated ASD patients reached MCID thresholds for all evaluated subgroups except for SRS-Mental Health. Using Medicare based DRG reimbursements the mean cost/QALY of $59,514 fell within the (WTP) threshold of 100K, but reaching MCID was not predictive of lower cost-per-QALY within any of the patient-reported outcome domains analyzed. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.