(SS#VI) Assessing the Role of Socioeconomic Disadvantage in Outcomes from 4233 Consecutive Single-level Spinal Fusions

Introduction: Socioeconomic factors influence access to healthcare and medical outcomes. The Area Deprivation Index (ADI) and Median Household Income (MHI) are well-studied surrogates for social determinants of health (SDOH). Whether these metrics relate to common neurosurgical outcomes has not been well-assessed. If so, they may inform strategies to mitigate care disparities. We aim to determine if ADI or MHI predicts outcomes after single-level spinal fusion.

Methods: 4,223 consecutive patients undergoing single-level, posterior-only lumbar fusion at a single multihospital academic medical center were prospectively enrolled and retrospectively analyzed. Geo-localized patients were cross-referenced to MHI census data (n=4223) and ADI (n=1831). First, logistic regression was used to correlate outcomes with MHI and ADI. Subsequently, two separate Coarsened Exact Matching protocols were undertaken. High-risk MHI and high-risk ADI patients were exact-matched to low-risk MHI and ADI patients, respectively. Matching controlled for key patient characteristics known to affect neurosurgical outcomes. Primary outcomes included 30- and 90-day readmissions, emergency department (ED) visits, reoperations, and mortality, as well as discharge disposition (home vs. non-home).

Results: By univariate analysis, ADI and MHI were both significantly (p < 0.05) associated with 30- and 90-day readmission, ED visits, reoperation, and non-home discharge, but not mortality. After exact matching for ADI (n=212), high-risk patients were less likely to be discharged to home (OR=3.83) and, at both 30 and 90 days, more likely to be readmitted (OR=5.00, 4.50, respectively), visit the ED (OR=3.00, 2.88), and undergo reoperation (OR=4.50, 5.50). After exact matching for MHI (n=270), low-income patients were less likely to be discharged to home (OR=2.25).

Conclusion : Socioeconomic disadvantage was associated with worse short-term outcomes in 4233 consecutive spinal fusion patients. Furthermore, ADI predicted more differences in postoperative outcomes than MHI. ADI, an effective and easily applied surrogate for SDOH, can guide enrollment for prospective randomized trials to mitigate care disparities.