<h3>BACKGROUND CONTEXT</h3> Frailty is a dynamic measure of physiological age that is a strong predictor of a patient's surgical risk. The purpose of this study is to investigate the impact of frailty on the perioperative outcomes and costs associated with operating on frail ASD patients. <h3>PURPOSE</h3> To investigate impact of frailty on operative course, clinical outcomes, and cost utility. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study of prospective, multicenter ASD database. <h3>PATIENT SAMPLE</h3> A total of 245 ASD patients were included. <h3>OUTCOME MEASURES</h3> Complications; health-related quality of life (HRQL)<b>:</b> ODI. <h3>METHODS</h3> Operative ASD patients (scoliosis >20, SVA>5cm, PT>25, or TK>60) with available baseline (BL) and 2-year (2Y) radiographic and HRQL data were included. The ISSG frailty index was used to stratify patients into 2 categories<b>:</b> not frail (NF) (<3) and frail (F) (>3). Univariate and multivariate analysis assessed differences in radiographic, surgical, and clinical factors. IHS-adjusted ODI and SRS compared recovery periods between F/NF patients. Cost utility using published methods convert ODI to SF-6D obtained Quality Adjusted Life Years (QALY). QALYs utilized a 3% discount rate for residual decline to life expectancy (78.7 years). Direct costs calculated using the PearlDiver database incorporating complications, LOS and associated health care costs. <h3>RESULTS</h3> A total of 245 ASD patients met inclusion criteria (57yrs±15.0, 82%F, BMI<b>:</b> 26.3 kg/m2 ±6.0, ASD-FI<b>:</b> 2.9±1.6, CCI<b>:</b> 1.55 ±1.7). Surgical patients had a mean number of levels fused of 11.4±4, LOS of 7.7 days±4.4, EBL of 1686 mL, operative time of 374 min, with 70% undergoing an osteotomy. In terms of surgical approach, 76% were posterior-only, and 23.6% had a combined approach. Frailty breakdown was: 138 (55%) NF and 107 (45%) F patients. F patients had higher mean PT (25 vs 20), PILL (21 vs 10), TK T4-T12 (-33 vs -36), SVA C7-S1 (80 vs 35), and a higher BL ODI (52 vs 27, all p <0.05). F patients had a higher level of invasiveness (99 vs 88), greater EBL (2058 vs 1560) and a longer LOS (8.6 vs 7, all p<0.05), as well as more overall complications (86% vs 78%, p=.094), more major complications (41% vs 24%, p=.003) and more reoperations (24% vs 18%, p=.314). Improvement in ODI was greater for frail patients (-19 vs -12); however, at 2Y ODI remained significantly higher (32 vs 15, both p<0.05). F patients had a higher IHS-adjusted ODI (32 vs 15, p<0.05). In a cost analysis, 2Y cost of F patients was higher ($90,967 vs $81,479); however, due to a greater gain in QALY, cost per QALY at life expectancy was comparable to NF patients ($71,600 vs $75,191). <h3>CONCLUSIONS</h3> Frail patients experienced a longer LOS and higher EBL, possibly due to the increased invasiveness used to treat a more severe deformity with a worse preoperative physiological state. Although frail patients experienced more complications, the higher overall improvement in ODI contributed to a comparable cost utility despite a higher initial cost. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.