National Readmission Trends in Patients with Adult Spinal Deformity Undergoing Posterior Spinal Fusion

Introduction: Adult spinal deformity (ASD) affects many people in the U.S., often causing significant back pain, requiring requires surgical intervention. The aim of this study was to assess the patient-level drivers of readmission after treatment of ASD.

Methods: A retrospective cohort study was performed using the 2016–2019 Nationwide Readmissions Database (NRD). All adult patients undergoing thoracic posterior spinal fusion (PSF) for ASD were identified using ICD-10 coding. Patients were stratified into 7-day, 30-day, 90-day, and no readmission cohorts. Demographic information and clinical outcomes were assessed. Multivariate analyses were performed to identify independent predictors of readmission.

Results: Of the 3697 patients included, 136 were readmitted within 7 days, 252 within 30, 168 within 90, and 3141 who were not readmitted. A significantly greater proportion of patients in the 7-day cohort were insured by Medicaid, while a significantly higher percentage of non-readmitted patients were privately insured (p < 0.001). The 30-day cohort had the highest frailty score, followed by the 90-day, 7-day, and non-readmitted cohorts (p < 0.001). The 7-day and 30-day cohorts had the highest percentages of those with 2 or more adverse events (p < 0.001). The 7-day cohort had the longest mean length of stay (LOS) (p=0.001), while the 30-day cohort had the greatest rate of non-routine discharge (p < 0.001). The most common reasons for readmission were infection, kidney failure, and pulmonary embolism. On multivariate analysis, LOS was independently associated with increased odds of 7-day readmission, while 2 or more adverse events and non-routine discharge were associated with increased odds of 30-day readmission. Only patient age was associated with increased odds of 90-day readmission.

Conclusion : Our study suggests that the initial hospital course, including adverse events experienced, LOS, and discharge disposition were independent factors in readmission after PSF for ASD. Future directions of study include investigating ways to minimize unwanted inpatient hospital outcomes for ASD patients.