Predictors of adverse discharge disposition in adult spinal deformity and associated costs

Abstract

Background context: With advances in the understanding of adult spinal deformity (ASD), more complex osteotomy and fusion techniques are being implemented with increasing frequency. Patients undergoing ASD corrections infrequently require extended acute care, longer inpatient stays, and are discharged to supervised care. Given the necessity of value-based health care, identification of clinical indicators of adverse discharge disposition in ASD surgeries is paramount.

Purpose: Using the nationwide and surgeon-created databases, the present study aimed to identify predictors of adverse discharge disposition after ASD surgeries and view the corresponding differences in charges.

Study design/setting: This is a retrospective analysis of patients on the National Surgical Quality Improvement Program (NSQIP) database and of cost data from Medicare PearlDiver Database.

Patient sample: Patients undergoing thoracolumbar surgery for correction of ASD were included in the study.

Outcome measures: Primary analysis was performed to compare patients discharged to home with patients who either expired or were discharged to locations other than home. Secondary analysis was performed to determine the cost differences across discharge groups.

Methods: Patients on NSQIP undergoing thoracolumbar ASD-corrective surgery with a primary diagnosis of scoliosis (ICD-9 code 737.x) and over the age of 18 were isolated. Predictors (demographic, clinical, and complications) of not-home (NH; rehab or skilled nursing facility) discharge were analyzed using binary logistic regression controlling for levels fused, decompressions, osteotomies, and revisions. Average 30- and 90-day costs of care were reported in home, rehab, and skilled nursing facility discharge groups in patients undergoing 8+ level thoracolumbar fusion.

Results: A total of 1,978 patients undergoing lumbar ASD-corrective surgery were included for analysis (average age: 59.3 years, sex: 64% female). Average length of stay was 6.58 days. On multivariate regression analysis, age over 60 years (odds ratio [OR]: 0.28, confidence interval [CI]: 0.22-0.34) and female sex (p=.003) were independent predictors of adverse discharge status. Partially dependent preoperational functional status, defined as reliance on another person to complete some activities of daily living, increased likelihood of adverse discharge disposition (OR: 0.57, CI: 0.35-0.90). Despite controlling for all clinical variables except for the ones specific to each analysis, Smith-Petersen osteotomy (OR: 0.51, CI: 0.40-0.64), interbody device placement (OR: 0.80, CI: 0.64-0.98), and fixation to the iliac (OR: 0.54, CI: 0.41-0.70) increased the likelihood of adverse discharge. Complications most associated with adverse discharge were urinary tract infections (OR: 0.34, CI: 0.21-0.57) and blood transfusions (OR: 0.42, CI: 0.34-0.52). Relative to home discharge, 30-day costs of care were +$21,061 more expensive in rehab discharges, but not different in skilled nursing facility discharges (+$5,791, p=.177). The 90-day costs of care were $23,815 in rehab discharges (p<.001), but again not different from skilled nursing facility discharges (+$6,091, p=.212).

Conclusions: Discharge destination to rehabilitation has a significant impact on the cost of thoracolumbar ASD surgeries. Patient selection can predict patients at higher risk of discharges to rehab or skilled nursing facility.

Keywords: Adult spinal deformity; Cost; Discharge; NSQIP; Predictor; Rehabilitation; Surgery.