Association of frailty with healthcare resource utilization after open thoracic/thoracolumbar posterior spinal fusion for adult spinal deformity

Purpose The Hospital Frailty Risk Score (HFRS) is a frailty-identifying metric developed using ICD-10-CM codes. While other studies have examined frailty in adult spinal deformity (ASD), the HFRS has not been assessed in this population. The aim of this study was to utilize the HFRS to investigate the impact of frailty on outcomes in ASD patients undergoing posterior spinal fusion (PSF). Methods A retrospective study was performed using the 2016–2019 National Inpatient Sample database. Adults with ASD undergoing elective PSF were identified using ICD-10-CM codes. Patients were categorized into HFRS-based frailty cohorts: Low (HFRS < 5) and Intermediate-High (HFRS ≥ 5). Patient demographics, comorbidities, intraoperative variables, and outcomes were assessed. Multivariate regression analyses were used to determine whether HFRS independently predicted extended length of stay (LOS), non-routine discharge, and increased cost. Results Of the 7500 patients identified, 4000 (53.3%) were in the Low HFRS cohort and 3500 (46.7%) were in the Intermediate-High HFRS cohort. On average, age increased progressively with increasing HFRS scores ( p < 0.001 ). The frail cohort experienced more postoperative adverse events ( p < 0.001 ), greater LOS ( p < 0.001 ), accrued greater admission costs ( p < 0.001 ), and had a higher rate of non-routine discharge ( p < 0.001 ). On multivariate analysis, Intermediate-High HFRS was independently associated with extended LOS ( OR: 2.58, p < 0.001 ) and non-routine discharge ( OR: 1.63, p < 0.001 ), though not increased admission cost ( OR: 1.01, p = 0.929). Conclusion Our study identified HFRS to be significantly associated with prolonged hospitalizations and non-routine discharge. Other factors that were found to be associated with increased healthcare resource utilization include age, Hispanic race, West hospital region, large hospital size, and increasing number of AEs.