Risk factors for the incidence of delirium in geriatric spinal surgery patients: a multicenter retrospective observational study

Objective: Delirium is a frequent and serious postoperative complication in older adults after spinal surgery, linked to prolonged hospitalization, cognitive decline, and increased mortality. Despite its clinical significance, multicenter data in Korea remain limited.Methods: This retrospective multicenter study analyzed 1,284 patients aged ≥75 years who underwent spinal fusion for degenerative lumbar disease across seven institutions between January 2022 and September 2023. Delirium was diagnosed using Diagnostic and Statistical Manual of Mental Disorders-5 criteria documented in electronic medical records. Demographic, clinical, and perioperative variables were compared between patients with and without delirium. Logistic regression was used to identify independent predictors.Results: Delirium occurred in 154 patients (12.0%), with marked inter-center variability in incidence (3.8%–33.3%). Among delirium cases, antipsychotics were prescribed in 165 instances (107.1%; range, 96.2%–283.3%), while psychiatric consultations were obtained in 112 cases (72.7%; range, 1.9%–316.7%), reflecting inconsistent management practices. In univariate analysis, older age, male sex, taller height, smoking, and opioid use history were associated with delirium. Multivariate analysis identified older age (adjusted odds ratio [OR], 1.08; 95% confidence interval [CI], 1.01–1.16), male sex (adjusted OR, 1.42; 95% CI, 1.03–1.96), and opioid history (adjusted OR, 2.18; 95% CI, 1.45–3.25) as independent predictors.Conclusion: Postoperative delirium in geriatric spinal surgery patients demonstrates substantial inter-institutional variability in diagnosis and management across Korea. Independent predictors included older age, male sex, and opioid history. These findings highlight the importance of standardized diagnostic criteria, consistent psychiatric involvement, and opioid-sparing strategies to optimize delirium prevention and management in this vulnerable population.