Patient Outcomes in Safety-Net Hospitals After Surgery for Ankylosing Spondylitis

Introduction: Safety-Net Hospitals (SNHs) provide invaluable care for many patients with Medicaid or without insurance. However, few prior studies have assessed the association between SNH status and hospital outcomes following posterior spinal fusion (PSF) for ankylosing spondylitis (AS). The aim of this study was to assess the relationship between SNH status and outcomes after PSF for AS.

Methods: Using the National Inpatient Sample (NIS) database, a retrospective study was conducted on adult patients with AS who underwent posterior spinal fusion for fracture between 2016-2019. Patients were stratified by SNH status, defined as hospitals in the top quartile of Medicaid/uninsured patient admissions. All other hospitals were defined as non-SNHs (N-SNHs). Logistic multivariate regression analyses were performed to identify associations between SNH status and extended length of stay (LOS), non-routine discharge (NRD), and exorbitant admission costs.

Results: Of the 1980 patients included, 1495 received treatment at N-SNHs and 485 at SNHs. Patients treated at SNHs were more likely to be non-White compared to those at N-SNHs (p=0.017). Patients in the SNH cohort were more likely to receive treatment at large, urban teaching hospitals in the South compared to those treated at N-SNHs. Comorbidity burden and rate of adverse events were similar between both cohorts. Median LOS (p=0.021) and cost were higher at SNHs (p=0.026). On multivariate analysis, experiencing 2 or more adverse events was independently associated with an increased odds of an extended LOS, NRD, and exorbitant costs. Being treated at an SNH was not independently associated with extended LOS, NRD, or exorbitant cost.

Conclusion : Our study suggests that patient demographics differed between SNH and N-SNHs and that SNH status may influence outcomes after PSF for AS. Further research is required to understand the disparities among hospitals that may lead to poorer outcomes in some populations.