Disparities Attributable to Sex Differences in 4680 Lumbar Fusion Outcomes

Ritesh Karsalia; Ryan S Gallagher; Austin J Borja; Emily Xu; Jianbo Na; Scott D McClintock; Neil R Malhotra

doi:10.1016/j.wneu.2024.123586

Disparities Attributable to Sex Differences in 4680 Lumbar Fusion Outcomes

World Neurosurg. 2024 Dec 20:123586. doi: 10.1016/j.wneu.2024.123586. Online ahead of print.

Authors

Ritesh Karsalia¹, Ryan S Gallagher¹, Austin J Borja¹, Emily Xu¹, Jianbo Na², Scott D McClintock³, Neil R Malhotra⁴

Affiliations

¹ Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
² Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; McKenna EpiLog Fellowship in Population Health, at the University of Pennsylvania, Philadelphia, PA, USA.
³ West Chester University, The West Chester Statistical Institute and Department of Mathematics, 25 University Ave, West Chester, PA, USA.
⁴ Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; McKenna EpiLog Fellowship in Population Health, at the University of Pennsylvania, Philadelphia, PA, USA. Electronic address: neil.malhotra@pennmedicine.upenn.edu.

PMID: 39710198
DOI: 10.1016/j.wneu.2024.123586

Abstract

Background: While studies have examined the relationship between sex and outcomes after lumbar fusion surgery, few have strictly controlled for other patient-level variables. In this study, we use coarsened exact matching to determine the effect of patient-reported sex on spinal fusion outcomes.

Methods: Outcomes across 4680 consecutive adult single-level, posterior-only lumbar fusions at a multihospital academic medical center were retrospectively assessed. First, univariate analyses were performed to broadly examine the effect of sex on surgical outcomes, uncontrolled for other patient factors. Next, the population was split by sex (male vs. female) and matched 1:1 on demographic and medical factors known to influence outcomes (including age, race, smoking status, and past surgical history) using coarsened exact matching (CEM). CEM effectively controls for confounding variable bias by creating pairs of matched samples and preserving the fidelity of each covariate through binning. Primary outcomes included 30- and 90-day readmissions, Emergency Department visits, reoperations, and mortality. Secondary outcomes included discharge disposition and length of hospital stay.

Results: Between otherwise exactly matched male-female pairs, females were less likely to be discharged home (OR 1.70, p<0.001) and had a longer length of stay (mean: 95.7 vs 87 hr, p<0.001). No differences in readmissions or reoperations were observed between matched cohorts.

Conclusion: Female patients encountered longer hospital stays and higher odds of non-home discharge after single-level lumbar fusion compared to otherwise exactly matched male patients.

Keywords: Hospital readmissions; Lumbar fusion; Outcomes; Sex; Spine surgery.